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Henkel, Timothy P. "Ecology of the obligate sponge-dwelling brittlestar Ophiothrix lineata." View electronic thesis, 2008. http://dl.uncw.edu/etd/2008-3/r1/henkelt/timothyhenkel.pdf.
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Beaulieu, Stace. "The ecology of glass sponge communities in the abyssal NE Pacific /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1998. http://wwwlib.umi.com/cr/ucsd/fullcit?p9907821.
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Trautman, Donelle Ann. "Aspects of the ecology and physiology of a tropical sponge and its macroalgal symbiont." Thesis, Trautman, Donelle Ann (1996) Aspects of the ecology and physiology of a tropical sponge and its macroalgal symbiont. PhD thesis, Murdoch University, 1996. https://researchrepository.murdoch.edu.au/id/eprint/51822/.
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This study examined ecological and physiological aspects of the symbiotic relationship between the tropical sponge Haliclom cymiformis and the red macroalga Ceratodictyon spongiosum at One Tree Reef, Great Barrier Reef. Although Haliclona/Ceratodictyon occurs commonly in the shallow waters of coral reefs, the biology of this association, nor any other sponge-macroalgal association, has ever been studied in detail.
At One Tree Reef, I found that populations of the Haliclona/Ceratodictyon association were generally restricted to the rubble banks just inside the north eastern rim of the reef crest which surrounds One Tree Lagoon. Only one population of the association was found in the centre of the lagoon. At the rubble bank sites, large populations of the Haliclona/Ceratodictyon association appear to be maintained by asexual reproduction Strong wave turbulence often fragments larger sponges and the size-frequency distribution was strongly skewed toward smaller individuals. In the centre of the lagoon, individuals of the association grew to much larger sizes than those found at the rubble banks, even though this site has a sandy, rather than rubble, floor and was shown to have higher rates of sedimentation, lower irradiance and less turbulence than the rubble bank sites. It appears that the lack of suitable rocky substrata in the centre of the lagoon limits the recruitment of the association into new areas. Fusion experiments between intact individuals of Haliclona/Ceratodictyon collected from different sites. both on the edge and in the centre of One Tree Lagoon, showed sufficient histocompatibility to suggest that existing populations of Haliclona/Ceratodictyon may have originated from the same parent population.
Measurements of photosynthesis rates across a range of irradiances in the intact association were modelled using the hyperbolic tangent function, and me results showed that this association makes a significant contribution to the primary productivity of One Tree Lagoon. Haliclom/Ceratodictyon was shown to have a high rate of photosynthesis; during summer, maximum rates of photosynthesis produced approximately 434 µmol 02 mg chl a-1.h-1, at a saturating light intensity of 749 µmol photons.m-2.s-1 (i.e. the minimum irradiance required to reach the maximum rate of photosynthesis). Compensation irradiance (where the rate of photosynthesis is equal to the rate of respiration) was approximately 316 µmol photons.m-2.s-1, and the slope of the plot of photosynthesis versus irradiance at sub-saturating irradiances (a) was 0.77. The rate of respiration was also high, consuming 218 µmol O2 mg chl a-1.h-1. During winter the rate of maximum photosynthesis and the rate of respiration generally decreased as did the saturating irradiance, and the irradiances required to bring about maximum photosynthesis and compensation photosynthesis. The rates of photosynthesis at irradiances lower than the saturating light intensity generally increased at this time of year.
Photosynthesis and respiration in intact Haliclona/Ceratodictyon occurred at the same rate in the growing tips of the association and near the base. These rates were not affected by concentrations of oxygen up to 287.5 µmol O2.l-1, or by short-term nutrient enrichment with nitrogen, phosphorus, or a combination of the two, to ten times the ambient lagoon concentration. Differences were found in the rates of photosynthesis and respiration between day and night, when pieces of the association were exposed to the same levels of irradiance at different times over a 24 h period. Changes in temperature also affected the rates of photosynthesis and respiration in the intact association; the mean Q10 values for respiration and photosynthesis between 15°C and 30°C were 2.14 and 2.46 respectively. Photosynthetic rate and photosynthetic pigment concentrations were also increased when clumps of Haliclona/Ceratodictyon were subjected to prolonged reductions in irradiance. Similar results were obtained from pieces of the association which were collected from the site in the centre of One Tree Lagoon where the water held large volumes of suspended sediments.
Isolation of both the sponge and algal tissue was achieved in this study, but isolated sponge cells never survived for longer than 48 h. Isolated algal filaments could be maintained in culture for long periods but the photosynthetic rate was reduced following isolation and growth in culture, and they grew very slowly.
Active filter feeding by the sponge occurred at a constant rate during both day and night. The sponge could rapidly clear both particulate and dissolved organic matter from the water column. Despite high rates of photosynthesis and the presence of some ‘host release factor’ activity, relatively small quantities of photosynthetically fixed carbon appeared to be translocated from the isolated alga, when algal filaments were incubated in homogenized sponge tissue.
This association is therefore a significant primary producer, inhabiting areas in which not many large primary producers (algae or corals) can live. The success of Huliclona/Ceratodictyon in these environments is at least partly due to its ability to survive fragmentation, which is an important factor in the reproduction and dispersal of the association. The results presented here also suggest that the symbiosis is based on a structural rather than nutritional relationship between the partners. Thus the association is of unique physiological interest.
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Chak, Tin Chi Solomon. "Reproductive Altruism, Social Diversity and Host Association in Sponge-Dwelling Snapping Shrimps, Synalpheus." W&M ScholarWorks, 2016. https://scholarworks.wm.edu/etd/1477068130.
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The diversity of animal social strategies has interested evolutionary biologists since the time of Darwin. Eusociality—the apex of animal sociality—traditionally characterized by cooperative offspring care, overlapping generations and reproductive division of labor, was until recently known only in insects and a few vertebrate species. The independent evolution of eusociality in shrimps in the genus Synalpheus offers a unique opportunity to test the generality of social evolution theories that are based mainly on insects and social vertebrates. The genus Synalpheus is particularly ideal for comparative analysis because their social organizations are highly diverse, yet they share very similar ecology of being sponge dwellers. Further, their close associations with sponges, in which many are considered microbial fermenters, allow one to test the ecological drivers of species diversity in Synalpheus. In this dissertation, I first explored the nature and consequences of reproductive altruism in eusocial species. Chapter 1 showed that workers in eusocial Synalpheus retain reproductive capability, but reproduction of female workers is suppressed by the queen. Chapter 2 showed further that such reproductive inequity among females within a colony leads to potentially strong competition among females for reproductive opportunities, and is associated with reduced sexual dimorphism in eusocial Synalpheus species. Second, I examined the evolutionary trajectories between and ecological advantages associated with different social organizations in Synalpheus. Chapter 3 shows that the two demographically distinct social organizations found in Synalpheus—communality and eusociality—have evolved via separate evolutionary trajectories and represent alternative social strategies. Chapter 4 further shows that these social strategies are associated with different aspects of ecological advantages conferred on Synalpheus living together. Finally, the intimate association with host sponges constrains the lifestyle of Synalpheus and may be one factor that has predisposed their evolution of eusociality. In Chapter 5, I examined the association pattern of Synalpheus with their host sponges and found that the symbiotic microorganisms in sponges, rather than the phylogenetic histories of the host sponges, are a better predictor and potential driver of the host association pattern. This dissertation has sought to test, and ended up challenging, several paradigms in ecology and evolution. My results suggest that 1) polymorphic reproductive soldiers may represent a natural transition towards eusociality, 2) reproductive monopolization can modulate the pattern of sexual dimorphism in social species, 3) communality and eusociality evolved from distinct trajectories and have different ecological advantages, and 4) symbiotic microorganisms may mediate biological interactions between their hosts and other organisms.
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Witowski, Chris G. "Investigation of Bioactive Metabolites from the Antarctic Sponge Dendrilla membranosa and Marine Microorganisms." Scholar Commons, 2015. https://scholarcommons.usf.edu/etd/5602.
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Natural products continue to be a valuable source of compounds in research involving chemical ecology and drug discovery. Secondary metabolites are biosynthesized to benefit the host organism in its environment (feeding deterrence from predators, antibiotic properties to avoid infection, etc.) but these compounds also serve as useful scaffolds in drug discovery applications. The research herein describes both aspects of these two branches of natural products chemistry. The Antarctic sponge Dendrilla membranosa produces diterpenes, of which membranolide A, deters feeding of the predatory amphipod Gondogenia antarctica. A metabolomic study of several sponges was undertaken to determine environmental factors that govern the metabolism of D. membranosa. Habitat specificity, above or below the algal canopy, was a significant factor for the chemical clustering of sponges as well as the abundance of potential amphipod predators that are prevalent within the canopy. Another D. membranosa diterpene, aplysulphurin, undergoes degradation upon methanolic treatment to form the methoxy membranolides B-H. An investigation of these artifacts reveals potent activity against the leishmaniasis-causing parasite Leishmania donovani. Microorganisms also generate a significant number of bioactive natural products. Biotic and abiotic culture stressors such as co-culturing and epigenetic modification, respectively, will be explored to turn on cryptic biosynthetic pathways. These techniques are shown to produce unique secondary metabolites from cultures and further reinforce the one strain many compounds approach to the versatile and formidable microbial domain.
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Abdo, David A. "Maintenance and structuring of two temperate Haliclonid sponge populations." University of Western Australia. School of Plant Biology, 2007. http://theses.library.uwa.edu.au/adt-WU2008.0197.
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[Truncated abstract] Sponges have an invaluable ecological importance through the provision of shelter and habitat, consolidation of reefs, bio-erosion, and in benthic-pelagic coupling processes. In addition, sponges are known to be an incredible source of compounds with bio-medicinal and commercial applications. Despite their ecological and economic importance, our understanding of the processes which maintain and structure sponge populations is severely lacking compared to other sessile invertebrates (e.g. Cnidarians). This study examines the processes which help maintain and the factors which structure the populations of two sympatric Haliclona species (Demospongiae; Haplosclerida; Chalinidae) at Hamelin Bay on the south west coast of Australia. In addition, the importance of both species to the broader marine community is examined. The reproductive biology of both species was determined from histological sections taken from each species over two years at Hamelin Bay. No evidence of asexual reproduction was observed in either species. Sexual reproduction occurred from November to April in Haliclona sp. 1 (hereafter green Haliclona) and November to May in Haliclona sp. 2 (hereafter brown Haliclona). The green Haliclona is viviparous with both gonochoric and hermaphroditic individuals observed in the population. The brown Haliclona is also viviparous with separate sexes. The onset and progression of reproduction in both species corresponded to increases in water temperature and photoperiod, but only decreasing wave height showed a significant correlation to gametogenesis. ... A significant (P < 0.05) difference in concentration between seasons was also observed, suggesting environmental and physiological factors affect the production of salicylihalamide A in the green Haliclona. The importance of each species to the marine environment was assessed by investigating the endofauna inhabiting each species across their known range ( [approx. ]1000 km's). A total of 948 and 287 endofaunal individuals were found associated with the green and brown Haliclona, respectively. Twenty four endofaunal taxa were found (from mysid shrimps to teleost fish), and the endofaunal assemblages of each species were significantly different. However, only the endofaunal assemblage associated with the green Haliclona varied among locations. Overall, this study demonstrates that the populations of both species are maintained by limited sexual reproductive output and larval dispersal. Abiotic factors (e.g. water temperature, wave exposure) influence the growth and physiology of both species, which is intimately connected to their abilities to reproduce. This has important consequences for the species populations with regard to their resilience to environmental change, and potential for harvesting of biomass for supply of bioactive compounds. Additionally, both species provide important habitats for many other organisms. The findings highlight the need for a detailed understanding of the ecology of potentially exploitable sponge species, to ensure their conservation and limit the impact on the organisms which rely on the sponges.
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Andringa, Stephanie Lynn. "Ecology, Population Dynamics, and Sexual Characteristics of Commensal Leucothoid Amphipods with the Sponge Cliona varians in the Florida Keys (Crustacea: Amphipoda)." NSUWorks, 2015. http://nsuworks.nova.edu/occ_stuetd/28.
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Recent observations have identified a new species of leucothoid amphipod, Leucothoe “sp. F,” associated with the sponge Cliona varians. This project examined the relationship between this amphipod and its sponge host at three sites in the Florida Keys with differing hydrodynamic regimes. Ninety-eight sponge samples with a total of 2,030 amphipods were collected between December 2011 and September 2012. Leucothoe “sp. F” is currently a common species in the Florida Keys strongly associated with C. varians; its distribution strongly coincides with open tidal currents from the Gulf of Mexico. Seasonality, depth, and tidal regimes not only influence population dynamics and sexual characteristics of Leucothoe “sp. F,” but also the abundance and volume of its host.
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Davis, Katie S. "Use of a Towed Camera System along the west Florida shelf: A Case Study of the Florida Middle Grounds Benthic Marine Communities." Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7494.
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As technologies advance the study of ocean dynamics, new approaches to vexing problems of scale and process are becoming more widely available. Originally conceived as a tool primarily for indexing the abundance of near-bottom fishes, the Camera-based Assessment and Survey System (C-BASS) may also be an effective tool for monitoring benthic invertebrate resources vulnerable to natural and anthropogenic perturbations, and for characterizing the composition of benthic communities to inform spatial management. Using still images derived from the C-BASS video of benthic transects within the Florida Middle Grounds, I documented the abundance of benthic habitat-forming functional groups—sponges, algae, and corals—and noted taxa that were present in a SCUBA and ROV study conducted a decade earlier. Images were pre-processed using MATLAB computer programming language to correct for light attenuation and scattering in seawater at depth, and examined using ImageJ software and Coral Point Count software or rapid visual assessment methodology to assess image quality and percent cover, respectively. Exploratory data analysis (dissimilarity profile) delineated five habitat types in the northern Florida Middle Grounds, and discriminating benthic cover was identified using similarity percentage analysis: soft corals, fleshy macroalgae, low-relief algae, encrusted rubble, and sand. Hard corals and sponges represented relatively low area cover. A canonical analysis of principle components of in situ environmental measurements, chlorophyll a, turbidity, salinity, slope, and depth highlighted the association of the sand habitat type with greater depths and least amount of slope. Fleshy macroalgae were associated with greater slope, which reflected its presence in transitional areas between sand and reef. Soft coral habitat type was correlated with shallower depths, but also to lower temperature and lower salinity, highlighting the limitations of one-time environmental measurements to the condition of that time and space. A distance-based redundancy analysis of fish species abundance revealed that sponges, soft corals, and hard corals explained some of the variation of Holocentridae spp., angelfishes, and porgy, and that gray snapper appeared to associate with higher measurements of chlorophyll a. A comparison of C-BASS measurements with a coincidental stationary camera survey revealed that a slight shift in view, either from the seafloor to the water column, or from two slightly different positions in the water column, can obscure or reveal benthic cover to varying degrees, suggesting that more imaging could provide more complete representations of the benthic cover. Continued surveys of the benthic composition of the west Florida shelf could elucidate the range of environmental conditions and facilitate further investigations into the fish species associations with biotic cover in these benthic communities.
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Davidson, Fiona. "Predicting Glass Sponge (Porifera, Hexactinellida) Distributions in the North Pacific Ocean and Spatially Quantifying Model Uncertainty." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40028.
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Predictions of species’ ranges from distribution modeling are often used to inform marine management and conservation efforts, but few studies justify the model selected or quantify the uncertainty of the model predictions in a spatial manner. This thesis employs a multi-model, multi-area SDM analysis to develop a higher certainty in the predictions where similarities exist across models and areas. Partial dependence plots and variable importance rankings were shown to be useful in producing further certainty in the results. The modeling indicated that glass sponges (Hexactinellida) are most likely to exist within the North Pacific Ocean where alkalinity is greater than 2.2 μmol l-1 and dissolved oxygen is lower than 2 ml l-1. Silicate was also found to be an important environmental predictor. All areas, except Hecate Strait, indicated that high glass sponge probability of presence coincided with silicate values of 150 μmol l-1 and over, although lower values in Hecate Strait confirmed that sponges can exist in areas with silicate values of as low as 40 μmol l-1. Three methods of showing spatial uncertainty of model predictions were presented: the standard error (SE) of a binomial GLM, the standard deviation of predictions made from 200 bootstrapped GLM models, and the standard deviation of eight commonly used SDM algorithms. Certain areas with few input data points or extreme ranges of predictor variables were highlighted by these methods as having high uncertainty. Such areas should be treated cautiously regardless of the overall accuracy of the model as indicated by accuracy metrics (AUC, TSS), and such areas could be targeted for future data collection. The uncertainty metrics produced by the multi-model SE varied from the GLM SE and the bootstrapped GLM. The uncertainty was lowest where models predicted low probability of presence and highest where the models predicted high probability of presence and these predictions differed slightly, indicating high confidence in where the models predicted the sponges would not exist.
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McQuillan, Lea. "Species richness, density and cover of sponge assemblages on temperate reefs off Perth, Western Australia." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2006. https://ro.ecu.edu.au/theses/359.
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Sponges were the dominant faunal benthic group, occupying 30 -50% of the limestone reef surface and displaying high diversity (>240 sponge species) on subtidal temperate reefs off Perth, Western Australia. Despite this high diversity there was little variation in composition among the six different sites sampled. However, there was within-site heterogeneity of sponge assemblages which has been ascribed to small-scale variation in light and sedimentation/abrasion rates. Differences in sponge assemblages were also detected between sampling times, species richness and sponge density were higher in winter compared to summer, whereas, sponge cover was higher in summer compared to winter. The results suggest that the growth and development of juveniles or annuals may have been adversely affected by the harsh conditions of winter. The higher temperatures in summer appeared to promote growth and reproduction of sponges.
Rapid assessment techniques have been proposed to look for patterns in biodiversity in conservation biology studies, when detailed routine surveys are not feasible. Two rapid assessment techniques were assessed, firstly examining the dominant sponge species; and secondly aggregating the sponge species to order level. The results of two rapid assessment techniques were promising if comparing sponge assemblages across habitats. If the aim was to assess sponge assemblages across sites, neither rapid assessment technique showed the same results compared to species level data. The general conclusion for subtidal temperate reef sponge assemblages within Marmion Lagoon is that there is substantial loss of information for spatial comparisons when aggregating species to order level or using only the dominant sponges. What was found was that the two levels failed to detect differences among sites which were found in the species level data analyses, but all three analyses gave the same results for habitat data.
In Western Australia only a few studies on sponges have been undertaken along the extensive coastline (12,500 km long). Previous sponge research in Western Australia occurred predominately as a result of taxonomic collections from expeditions undertaken in the 19th and early 201 h centuries. This study has described the 43 dominant sponge species that were found at six different sites on subtidal temperate reefs in Marmion Lagoon, Western Australia. Sponges were the dominant fauna found at most of the research sites off this coastal Perth location and included many species from a range of orders and families. Most of the species found occurred in sciaphilic (shade-loving) habitats. Only a few species occurred in full light conditions on the reef flats.
This study documented 243 sponge species from subtidal limestone reefs between 8-12 metres in depth within the Lagoon. These 243 species comprised 197 siliceous sponges (Class Demospongiae) and 46 calcareous sponges (Class Calcarea) and were identified to at least order. Eighteen were identified to order, 88 to family, 35 to genus and 56 to species level. Approximately 30% of the species recorded here are possibly new to science.
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Potens, Renee Michelle. "Characterization of the Marine Sponge Amphimedon compressa Microbiome Across a Spatial Gradient." NSUWorks, 2016. http://nsuworks.nova.edu/occ_stuetd/413.
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Diverse and ecologically important microbial communities (microbiomes) are symbiotic within marine sponges. In this study, the microbiome of Amphimedon compressa from three sample locations (Broward and Dade Counties, Southeast Florida, USA and the Southern Caribbean, Bocas del Toro, Panama) is characterized using 16S rRNA Illumina sequencing. The predominant taxa are Proteobacteria and Cyanobacteria, as expected for Low Microbial Abundance sponges, accounting for over 53% of the total microbiome community. The numbers of Operational Taxonomic Units (OTUs) decrease from Broward County (2,900) to Dade County (2,300) and then Bocas del Toro (1,200). The correlates to a decreasing north-south gradient of sponge microbiome richness and diversity. Sponge microbiome richness and Alpha diversity are nearly identical from the two closest locations (37 km), both in Southeast Florida (Tukey HSD/ANOVA; p=0.999). However Panama sponge microbiome richness and Alpha diversity are distinctly lower, with the primary driver being distance, ~1,850 km from Southeast Florida. Abiotic factors driving this trend of decreased richness and diversity include increased temperature, and deceased salinity in relation to precipitation-based seasons. Sponge microbiome Beta diversity as determined by Bray-Curtis Dissimilarity and Non-Metric Multidimensional Scaling documents the clustering of Panama samples as distinct from the Broward and Dade County samples. In a seasonal comparison, Broward County sponge microbiome richness (p=0.026, r2=0.92) and Alpha diversity (p=0.007, r2=0.98) are significantly different, documenting robust effects of temperature. This comparison confirms lowest microbiome OTU diversity in the season with highest precipitation and highest temperatures of 29.8 °C. These results are consistent with prior studies that report decreasing microbiome OTU richness and diversity under conditions of environmental stress such as decreased salinity and increased temperatures.
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Yasman. "Structure elucidation, biological activity, and ecology of terpene isocyanides from Phyllidiid species (Nudibranchia) and their sponge preys from The Thousand Islands National Park, Indonesia." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=979729696.
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Vargas, Ramirez Sergio. "Evolution and ecology of antarctic sponges." Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-141266.
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Peters, Kevin J. "The chemical ecology of Antarctic sponges." Birmingham, Ala. : University of Alabama at Birmingham, 2009. https://www.mhsl.uab.edu/dt/2009p/peters.pdf.
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Thesis (Ph. D.)--University of Alabama at Birmingham, 2009.Additional advisors: Bill J. Baker, James B. McClintock, Donald D. Muccio, Robert W. Thacker. Description based on contents viewed June 3, 2009; title from PDF t.p. Includes bibliographical references.
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López, Acosta María. "Silicon consumption by marine sponges: an empirical approach and its ecological implications." Doctoral thesis, Universitat de Barcelona, 2018. http://hdl.handle.net/10803/663476.
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Silicon (Si), in its dissolved form of silicic acid (DSi), is a key nutrient in the ocean. The availability of such nutrient in marine ecosystems is regulated through its use by silica-secreting organisms, a variety of groups including protists, algae, and animals that consume DSi to build their silica (BSi) skeletons. The interest in determining how Si cycles in the ocean is high, since it interacts with the cycling of other major nutrients and ocean primary productivity. Because diatoms are the most abundant Si users, the scientific attempts to quantify the Si utilization in the ocean have been only focused on these organisms, considering negligible the role of other Si users. Over the last decades, some studies have suggested that at least another group, the siliceous sponges, are also playing a non-negligible role in the consumption of Si in marine ecosystems.
Marine sponges are conspicuous animals in benthic ecosystems. They are common across the world ocean, irrespective of the latitude and depth, being able to form enormous aggregations that may extend over large areas. Both their ubiquity and their abundance make sponges good candidates to develop relevant functional roles in marine ecosystems. Regarding the use of Si, it is surprising that, despite about 80% of the sponge species require from DSi to elaborate their skeleton, almost no information is available about how sponges consume such nutrient. In fact, before the beginning of this PhD, only few studies had investigated DSi consumption in marine sponges, with kinetic models available for only four species in two genera of demosponges. This lack of knowledge sparked this PhD, which has been developed in the frame of three research grants: 1) “A research action to quantify fluxes and sinks of silicon through sponges: a neglected circuit within the marine cycle” (MEC–CTM2012-37787); 2) “Exploring the biological production of silica and its applications in science and technology” (MINECO-CTM2015-67221- R); and 3) WP4 —Ecosystem functions, services, and goods— in the EU’s project SponGES (H2020-No. 679849). The main objective of the work was to improve the general understanding on how sponges utilize DSi, to facilitate further assessment of the quantitative role of the sponges as Si users.
Here we investigated the kinetics of DSi consumption in five sponge species: four temperate, shallow-water demosponges and, for the first time, a cold, deep-water hexactinellid sponge. We also examined the sources of between-species and between-individual variability in DSi consumption responses. Interestingly, we detected that DSi consumption kinetics can change seasonally in some species, what may have important implications when quantifying the role of sponges as Si users. Additionally, we determined for the first time the rate of DSi utilization by a sponge species in situ. The results significantly matched those estimated from the kinetic models obtained in the laboratory, supporting the use of long (>24h) incubations in laboratory to investigate DSi consumption kinetics in sponges, in contrast to the very short periods traditionally recommended for diatoms (< 3h). Finally, we used the empirically information gained on DSi consumption over the development of this PhD to estimate the utilization of DSi by a sponge assemblage at the ecosystem level, using as case study the bay of Brest (France).
In summary, this research showed that sponges have a noticeable role as Si users, even in a shallow-water ecosystem (the bay of Brest) where diatoms largely contribute to the phytoplankton biomass. Our results also indicated that sponges increase their role in marine ecosystems with increasing availability of DSi in seawater. Thus, sponges are predicted to play a relevant role as Si users in high-latitude and deep-water habitats, characterized by high DSi availability. All together, the siliceous sponges should be considered as Si users if we aim to accurately quantify the cycling of Si in marine ecosystems.El silicio (Si), en su forma disuelta de ácido silícico (DSi), es un nutriente clave en el océano. Su disponibilidad en los ecosistemas marinos la regulan varios grupos de organismos, los cuales consumen DSi para construir sus esqueletos de sílice (BSi). Debido a que las diatomeas son el consumidor de Si más abundante, los intentos por cuantificar el uso del Si en el océano se han centrado principalmente en estos organismos, considerando el papel de los otros usuarios de Si como irrelevante. Durante las últimas décadas, algunos estudios han sugerido que al menos otro grupo, las esponjas silíceas, también están jugando un papel no-despreciable en el consumo de Si en los ecosistemas marinos. Las esponjas marinas son animales abundantes en los ecosistemas bentónicos. Es sorprendente que, pese a que el 80% de las especies necesitan DSi para formar sus esqueletos, casi no existe información disponible sobre cómo las esponjas consume dicho nutriente. De hecho, antes del comienzo de esta tesis (inicios del 2014), solo unos pocos estudios habían investigado el consumo de DSi en esponjas marinas, con modelos cinéticos sólo disponibles para dos géneros de demosponjas. Así, el principal objetivo de este trabajo fue mejorar el conocimiento general de cómo las esponjas utilizan DSi, facilitando futuras cuantificaciones del papel de las esponjas como usuarias de Si. Primero, investigamos las cinéticas de consumo de DSi en cinco especies de esponjas, incluida, por primera vez, una especie de la Clase Hexactinellida. También examinamos las fuentes de variabilidad entre especies y entre individuos, detectando que en algunas especies pueden ocurrir cambios estacionales en las cinéticas de consumo. Además, determinamos por primera vez la tasa de uso de DSi en esponjas en su hábitat natural (in situ). Los resultados, significativamente concordantes con los estimados por modelos cinéticos obtenidos en el laboratorio, respaldan el uso de incubaciones largas (>24h) en el laboratorio para investigar las cinéticas de consumo de DSi en esponjas. Finalmente, usamos toda la información empíricamente obtenida durante esta tesis para estimar el uso de DSi por parte de una comunidad de esponjas al nivel de ecosistema: la bahía de Brest (Francia). En resumen, este trabajo muestra que las esponjas tienen un papel relevante como usuarios de Si, incluso en un ecosistema somero en donde las diatomeas contribuyen ampliamente a la biomasa fitoplanctónica. Nuestros resultados también indican que el papel de las esponjas en los ecosistemas marinos aumenta junto con la disponibilidad de DSi. Por tanto, se predice que las esponjas jueguen un papel importante como usuarios de Si en hábitats profundos y de latitudes altas, caracterizados por alta disponibilidad de DSi. Todo ello indica que las esponjas silíceas deben ser consideradas como usuarios de DSi si queremos cuantificar de forma precisa el ciclo del Si a través de los ecosistemas marinos.
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Gonzalez, Rivero Manuel Alejandro. "The ecology of bioeroding sponges on Caribbean coral reefs." Thesis, University of Exeter, 2011. http://hdl.handle.net/10036/3574.
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Sponges contribute to large number of functions in coral reef ecosystems. Among these, bioerosion is perhaps one of the most widely studied, largely due to the important contribution of excavating sponges to the carbonate budget on coral reefs (up to 95 % of the total internal bioerosion). Despite our current knowledge, much of the literature is centred on individual-based observations, and little is known about their ecological role and interactions with other reef taxa in complex coral reef systems. The aim of this thesis was to quantify the ecological interactions of bioeroding sponges with major reef taxa by scaling up individual observations to population and ecosystem-based approaches. A cosmopolitan, abundant and highly competitive bioeroding sponge from Glover’s Atoll, Belize (Cliona tenuis) was used as model species. Monitoring of C. tenuis populations throughout 2009 indicated a trade-off between reproduction and growth, with the highest growth rates (31.4 ± 5.6 mm.y–1) occurring in summer, and a peak in reproductive output during winter. Populations typically show strong left-skewed size frequency distributions, mostly represented by juvenile-size individuals (46%), suggesting that regulating mechanisms (e.g. competition and predation) may be acting in constraining the transition of juveniles to adult sizes. Long-term in situ manipulations showed no effect of predation, yet competition with macroalgae significantly reduced the size of the sponge by 38% ± 11% (SE). While C. tenuis exhibit high growth and recruitment rates that could theoretically result in rapid population growth, the likelihood of sponges forming an alternative stable state as reefs sustain greater levels of disturbance is unclear. An analytical modelling approach of the interplay between macroalgae, coral and sponge was used to explore the likelihood of alternate stable states. The results show that irrespective of successful sponge invasion, inclusion of this third antagonist (in the interplay between coral and macroalgae) can qualitatively affect the likelihood of alternative stable state. The model exhibits emergent properties suggestive of intransitivity between the three competing taxa. Despite the potential of C. tenuis to benefit from disturbance, there are few cases in the literature reporting increases in bioeroding sponge abundance followed disturbance. Therefore, regulating mechanisms such as competition with other taxa, recruitment limitation or mortality are expected to exert demographic control on the populations of bioeroding sponges when space limitation is relaxed due to coral mortality. To determine processes regulating sponge populations, an individual-based spatial modelling approach was used to simulate the population dynamics of C. tenuis in a dynamic ecosystem environment. Using an orthogonal hypothesis testing approach, it was found that competition, and to a lesser extend partial mortality of the sponge tissue, largely regulate the population structure of C. tenuis. While reductions in coral cover may temporarily favour the rapid colonization by sponges, the competitive superiority of macroalgae may steal the opportunity from the opportunists.
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Puyana, Monica. "Chemical ecology of Caribbean sponges of the genus Aplysina /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2001. http://wwwlib.umi.com/cr/ucsd/fullcit?p3035429.
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Griffiths, Sarah Miriam. "Molecular approaches in conservation and ecology research in marine sponges." Thesis, Manchester Metropolitan University, 2018. http://e-space.mmu.ac.uk/620378/.
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Marine ecosystems face a challenging future as a result of human activity, and as such, it is vital to understand the ecology of marine organisms in order to effectively conserve them. Increasingly, molecular ecology tools are used for this purpose. In this thesis, I developed molecular resources for the study of sponges, an ecologically important and diverse marine group. Firstly, I developed a bioinformatics pipeline for the de novo isolation of microsatellites - genetic markers used to study intraspecific genetic diversity. Using this method, I characterised microsatellites for two Tropical Western Atlantic sponge species, Ircinia campana and Spheciospongia vesparium. These species have suffered mass mortalities in Florida Bay (Florida Keys, USA), with devastating effects on the ecosystem, and are currently among the subjects of an ecological restoration program. With these microsatellites, I investigated the spatial genetic structure of populations of both species across the Greater Caribbean and within the Florida Keys. I found genetic isolation by distance patterns over the region, indicating distance-limited dispersal, and also identified oceanographic barriers to population connectivity. On smaller spatial scales, genetic structure was also present, but patterns of genetic patchiness suggested that stochastic processes were more influential in determining structure at this scale. Finally, I investigated the effect of the Ircinia campana genotype on the composition of its associated microbial community. I found that more genetically similar sponges hosted more similar microbiomes, supporting the theory of a close coevolutionary relationship, and highlighting the importance of genetic diversity within species. With these insights on the distribution and effects of genetic diversity, I discuss the implications for sponge restoration in Florida Bay, and make recommendations for conservation practitioners to ensure resilience in sponge populations.
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Vargas, Ramirez Sergio [Verfasser], and Gert [Akademischer Betreuer] Wörheide. "Evolution and ecology of antarctic sponges / Sergio Vargas Ramirez. Betreuer: Gert Wörheide." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2012. http://d-nb.info/1020790687/34.
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Gomes, Hélder Alexandre Campos. "Ecological and biotechnological potential of sponge microbiome." Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/15450.
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Mestrado em Biologia Molecular e CelularMarine sponges harbor microbial communities of immense ecological and biotechnological importance. Recently, they have been focus of heightened attention due to the wide range of biologically active compounds with potential application, particularly, in chemical, cosmetic and pharmaceutical industries. However, we still lack fundamental knowledge of their microbial ecology and biotechnological potential. The development of high-throughput sequencing technologies has given rise to a new range of tools that can help us explore the biotechnological potential of sponges with incredible detail. Metagenomics, in particular, has the power to revolutionize the production of bioactive compounds produced by unculturable microorganisms. It can offer the identification of biosynthetic genes or gene clusters that can be heterologously expressed on a cultivable and suitable host. This review focus on the exploration of the biotechnological potential of sponge-associated microorganisms, and integration of molecular approaches, whose increasing efficiency can play an essential role on achieving a sustainable source of natural products.
As esponjas marinhas abrigam comunidades microbianas de grande importância ecológica e biotecnológica. Recentemente, estas têm recebido maior atenção devido ao grande número de compostos com actividade biológica, com potencial aplicação, particularmente, nas indústrias química, cosmética e farmacêutica. No entanto, a ecologia e o potencial biotecnológico dos seus microrganismos ainda permanecem largamente desconhecidos. O desenvolvimento de tecnologias de sequenciação de alta resolução deu origem a novo grupo de abordagens que nos podem ajudar a explorar o potencial biotecnológico das esponjas com um detalhe sem precedentes. As abordagens metagenómicas, em particular, tem poder para revolucionar a produção de compostos com actividade biológica produzidos por microrganismos não cultiváveis, ao permitir a identificação de genes ou clusters de genes biosintéticos com capacidade para serem expressos heterologamente num organismo hospedeiro adequado e cultivável. Esta revisão foca particularmente a exploração do potencial biotecnológico dos microrganismos associados a esponjas, e a integração de abordagens moleculares, cuja eficiência crescente pode desempenhar um papel essencial no desenvolvimento de uma fonte sustentável de produtos naturais.
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Evans, K. L. "Biodiversity of freshwater sponges (Porifera: Spongillidae) in the UK : taxonomy, distribution, and ecology." Thesis, University of Liverpool, 2016. http://livrepository.liverpool.ac.uk/3001399/.
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Ricciardi, Anthony. "Taxonomy, distribution and ecology of the freshwater sponges (Porifera:Spongillidae) and bryozoans (Ectoprocta) of eastern Canada." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61081.
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Specimens of freshwater bryozoans (Ectoprocta) and sponges (Porifera: Spongillidae), two of the most poorly known faunal groups in Canada, were obtained from various locations in Ontario, Quebec, New Brunswick, Nova Scotia, Prince Edward Island, and Newfoundland. A total of 14 species of bryozoans and 15 species of sponges were identified. In 31 cases, these species were recorded from a province for the first time. Species new to Canada include the bryozoans Lophopodella carteri, Plumatella orbisperma, and Pottsiella erecta, and the sponges Radiospongilla crateriformis, Spongilla aspinosa, and Trochospongilla horrida. The morphology, taxonomy, distribution, and ecology of each species are examined. Several taxonomic revisions are made. Eunapius mackayi and Plumatella orbisperma are redescribed. Spongilla heterosclerifera, considered an endangered species, is shown to be a species mixture. Taxonomic keys to Eastern Canadian species of freshwater bryozoans and sponges are presented. New limits of tolerance to pH, calcium and magnesium levels, and water temperature are established for several species.
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Sacristán, Soriano Oriol. "Chemical and microbial ecology of thc demosponge Aplysina aerophoba = Ecología química y microbiana de la demosponja Aplysina aerophoba." Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/128858.
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Phylum Porifera (Grant, 1836) are sessile metazoans with a differentiated inhalant and exhalant aquiferous system with external pores. Lacking a tissue grade of construction, sponges can reach two well-differentiated regions, the ectosome (external layer free of choanocytes) and the choanosome (internal region with choanocytes). As the most likely primitive metazoans, their challenging structural organization, physiology for biocalcification and trophic requirements allowed sponges to rapidly colonize distinct environments and built important sponge reefs during the Paleozoic and Mesozoic eras, making them an ecologically relevant group principally in marine benthic communities.
To date, sponges are still ecologically important among benthic fauna although the role as reef builders in modern coral reefs has changed in favor of scleractinian corals. Nonetheless, sponges have demonstrated a huge capacity to adapt and spread in many habitats contributing to organization and functioning at both community and ecosystem levels.
One of the keys of the evolutionary success of this group lies in the close association between sponges and microbes that dates back to the Precambrian era. The need to be defended may have arisen from the lack of motility of sponges and several mechanisms emerged to fulfill their demand including a chemical protection. Many sponges would have taken advantage of associated microbes to use their metabolites as a defense barrier against predators, competitors or foulers. This particular symbiosis has consequently become a key factor in biotic interactions within the sponge research. To date, chemical ecology and microbial ecology are two independent areas of the sponge research with ecological implications that occasionally converge at the same point. We want to analyze the evolution of the sponge chemical and microbial ecology from the very beginning, to quantify their impact on the scientific community, and to compare both research areas.
This PhD dissertation has been conceived to study the chemical and microbial ecology of sponges using the demosponge Aplysina aerophoba (Nardo, 1833) as a model species because its secondary chemistry and its associated microbial community are well studied and it is quite abundant in our study area (Northwestern Mediterranean and Canary Islands). Beyond the knowledge achieved about the major chemistry and bacterial assemblages in A. aerophoba, we have been able to explore the variation sources of the natural products and the sponge microbial consortium. Additionally, we have assessed the putative relationships between the host bacterial community and the production of secondary metabolites in this species.
We explored changes in the abundance of secondary metabolites and the relative composition of bacterial assemblages in A. aerophoba at multiple spatial (from few centimeters to thousand kilometers) and temporal (months and years) scales. The approach used allowed us to investigate which is the magnitude of the variance attributable to the distinct spatial and temporal scales and the most relevant scale at which the abundance of secondary metabolites and bacterial symbionts varied. We also investigated the relationship between natural products and microbial community structure by assessing whether both parameters covary at multiple scales. Finally, we experimentally addressed whether different light exposures can modify chemical and microbial profiles in the external and internal regions of A. aerophoba.
In summary, the production of natural products in sponges and the abundance and phylogenetic composition of the host-associated microbial community mainly depend to a large extent on the sponge-species and the ecological factors with spatial and temporal variations (e.g., light, predation, competition, fouling). The host state (i.e., stress) is also a key factor that may be the main driver of symbiotic shifts causing a breakdown in the sponge health and making the symbiont communities unstable and likely the sponge chemical defense. The combination between abiotic and biotic factors may finally determine the concentration of bioactive compounds and associated microbial diversity as the abiotic environmental context can control the outcomes of biotic interactions, and biotic interactions often moderate the effect of abiotic factors. For that reason, it is not an easy task to actually figure out the factors that limit or enhance chemical and microbial variability. Further experiments and time-series observations are needed to reveal the underlying processes hidden.El filo Porifera (Grant, 1836) está compuesto por metazoos sésiles con un sistema acuífero diferenciado del que forman parte los coanocitos que generan un flujo de agua unidireccional. A pesar de no presentar auténticos tejidos, las esponjas pueden llegar a desarrollar dos regiones bien definidas, el ectosoma (capa externa) y el coanosoma (región interna). Estos organismos representan un grupo ecológicamente importante del bentos marino con gran capacidad de adaptación y dispersión en muchos hábitats, contribuyendo así en la organización y funcionamiento a nivel de comunidad y ecosistema. Una de las claves del éxito evolutivo de las esponjas yace en la relación estrecha que presentan desde el Precámbrico con microorganismos a través de la cual desarrollaron una protección química. Muchas esponjas habrían utilizado los metabolitos secundarios de origen microbiano como defensa química. A día de hoy se han desarrollado dos áreas de investigación, la ecología química y la microbiana de esponjas, de las que realmente desconocemos su origen o su impacto. Dado el vacío existente de estudios que evalúen la comunidad bacteriana de esponjas como fuente de compuestos bioactivos, teníamos la oportunidad de integrar estos dos campos de la ecología de esponjas investigando la relación entre productos naturales y microorganismos simbiontes, con el fin de entender la funcionalidad de la comunidad bacteriana en el huésped. Esta tesis fue concebida para estudiar la ecología química y microbiana de la esponja Aplysina aerophoba (Nardo, 1833), cuya química y comunidad bacteriana asociada han sido objeto de muchos estudios previos. El principal objetivo fue explorar las fuentes de variación tanto de los productos naturales adscritos a Aplysina como de su estructura microbiana e inferir una posible relación entre comunidad de microorganismos y la producción de metabolitos secundarios. La aproximación que utilizamos consistía en explorar la variabilidad natural de los compuestos bioactivos y de la estructura microbiana de la esponja Aplysina aerophoba a distintas escalas espaciales (desde pocos centímetros hasta miles de kilómetros) y temporales (meses, años), y evaluar el efecto de factores ambientales, como la luz, en los perfiles químicos y microbianos. Posteriormente, correlacionar ambos patrones de variación e inferir alguna asociación potencial entre productos naturales y simbiontes microbianos. Resumiendo, la producción de metabolitos secundarios en esponjas y la composición filogenética de la microbiota asociada depende esencialmente de la especie de esponja, de los factores ecológicos con variación espacial y temporal, como también del estado del huésped (si presenta o no estrés). La combinación entre factores abióticos y bióticos determinará en última instancia la abundancia de defensas químicas y la diversidad microbiana debido a una autorregulación entre ambos tipos de factores.
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Kaye, Heather R. "Reproduction and bacterial symbiosis in Caribbean commercial sponges (Porifera: Demospongiae: Dictyoceratida)." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=75960.
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The genera Spongia and Hippospongia include all of the commercially important bath sponges of the Caribbean fishery. This study examined the uniform presence of immense symbiotic bacterial populations of four of these species: Hippospongia lachne, Spongia barbara, S. cheiris and S. graminea. The nutritional characteristics and antibiotic sensitivities of bacteria isolated from the four species were also examined. A combined light and transmission electron microscopic investigation outlined the reproductive processes and larval development, behaviour, settlement and metamorphosis in these four species.Symbiotic bacteria in these four sponge species are specific to the sponges and different from ambient seawater bacteria. Populations of intercellular bacteria within the tissues of these sponges are greater than those of ambient seawater. A variety of morphologically different types of sponge specific bacteria were observed. The symbionts are not fastidious organism but utilize a variety of amino acids, carbohydrates and tricarboxylic acid cycle intermediates as sole carbon and energy sources for growth. The bacteria showed sensitivities to a variety of antibiotics but were not susceptible to fluid from the sponges.
These sponges are viviparous and probably dioecious. Egg production and larval development are localized in patches or "nurseries" of endosomal tissue. Statistical analyses of specific morphological characteristics of female reproductive elements have identified four specific stages in the process of oogenesis. Umbilici connect young and maturing embryos to the maternal mesohyl and are the pathway for extracellular transfer of intercellular symbiotic bacteria and other mesohyl substances. These bacteria were observed in the embryos and larvae of all four species. Oocytes and embryos develop asynchronously within a given individual. Spermatogenesis occurs synchronously within cysts by transformation of entire choanocyte chambers. Cysts develop asynchronously within an individual. Male gametes exhibit a bright yellow-white autofluorescence when excited with blue light (460-485 nm). Spermatozoa do not possess intermediate segments or acrosomes.
The incubated parenchymella larvae of these four species are ovoid with dark grey pigmentation and enlarged posterior regions encircled by a black pigmented ring of cells bearing long cilia. Laboratory behavioural studies indicate that free-swimming larvae display directional swimming with constant rotation and negative phototaxis. Larval behaviour probably reflects the ecological situation of adult populations. Larval settlement occurs 26-56 hours after release and involves the rapid formation of a basal lamella between the larvae and substrate. There is no evidence of substrate selection or orientation by larvae. Precocious development of choanocytes does not occur in the larvae or post-larvae of these four species.
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Barnes, Peter Brendan. "Environmental impacts and the ecology of sponges and ascidians in south-eastern Australian coastal lakes and lagoons." Department of Biological Sciences - Faculty of Science, 2009. http://ro.uow.edu.au/theses/849.
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Estuaries worldwide are under threat from urbanisation and development and will need effective management for their successful conservation. Coastal lakes and lagoons have been identified as one of the estuary types most susceptible to human impacts largely because of their isolated nature and slow flushing times. Management of estuaries will be most effective when based on a sound scientific understanding of the patterns of distribution, biology and ecology over the full range of biodiversity of these systems, however, such an understanding is lacking for many systems and many taxa. Studies of sponges and ascidians in coastal lakes and lagoons are rare compared to other taxa, particularly in the southern hemisphere. This study represents the first detailed scientific investigation of the ecology of sponges and ascidian in coastal lakes and lagoons of southeastern Australia. Consequently, a large part of this thesis was devoted to quantifying basic patterns of distribution. I started with a pilot study to develop an effective sampling design, followed by large-scale comparisons among different types of lake, comparisons among habitats within lakes and an environmental impact study. I concluded with a manipulative experiment to examine processes responsible for smallscale patterns of distribution of sponges in seagrass meadows.In the pilot study, distributions of sponges and ascidians were quantified at a hierarchy of three spatial scales in each of two coastal lakes. Nested analyses of variance were then used to identify spatial scales at which variation was significant. Most sponges and ascidians were very patchily distributed at a range of spatial scales from 10s of metres up to 100s of kilometres. Unlike other published examples of cost– benefit analyses, very few taxa were widespread over the larger spatial scales. Cost– benefit analyses done to determine the optimal sampling design revealed inclusion of patchily distributed taxa in analyses improved the overall precision of sampling for comparisons of assemblages among lakes.Large-scale comparisons of assemblages of sponges and ascidians were made among lakes of different size (big versus small), opening regime (mostly open to the ocean versus mostly closed) and level of environmental modification (extensively modified versus more pristine). Similar to other taxa studied in coastal lakes, in general there were more species in lakes mostly open to the ocean compared to the mostly closed lakes, and importantly, no sponges and only one species of ascidian was found in the small closed lakes. There also appeared to be an effect of the level of modification of a lake with relatively smaller abundances of ascidians in extensively modified lakes, and a complete absence of sponges from one of the extensively modified lakes.Habitat-associated patterns were examined at smaller spatial scales by comparing the distributions of sponges and ascidians with the species composition and percentage cover of seagrass and macroalgae within two lakes; St Georges Basin and Wallis Lake. Several patterns of association were observed, but these varied among species of sponge and ascidian. In St Georges Basin, the most common sponge, Aplysinella cf. rhax and the native ascidian Pyura stolonifera were positively correlated with the seagrass, Posidonia australis. In contrast, the introduced ascidian, Styela plicata was more abundant in areas dominated by the seagrass, Zostera capricorni. In Wallis Lake, sponges were most diverse and some species most abundant in large beds of the macroalga, Lamprothamnion sp., while other sponges were found only on the holdfasts of brown macroalgae. In both lakes, sponges were generally less common in areas dominated by dense meadows of the seagrass, Zostera capricorni.Among the many anthropogenic impacts threatening the ecology of coastal lakes, the discharge of cooling water from coal-fired power stations represents an almost ideal case study from which to develop appropriate sampling regimes for detecting impacts on sponges and ascidians. Using reference locations both within and outside Lake Macquarie which has two cooling water outlets, I found assemblages of sponges and ascidians were often more diverse, more abundant and less temporally variable near to the outlets compared to reference locations.Based on the observation that the sponge, Suberites sp. which contains photosynthetic symbionts was absent from meadows of dense Zostera capricorni, I used in situ manipulative experiments in Smiths Lake to investigate processes which maybe affecting their distribution. Individual Suberites sp. were shaded, had water flow reduced and were transplanted into areas of dense Z. capricorni. There were no measurable short-term effects of shading or reduced water flow, but transplanted sponges were quickly eaten and I concluded predation by fish was likely to be a key process determining small-scale patterns of distribution of Suberites sp. in seagrass meadows. This result was in stark contrast to the majority of previous studies of the effects of seagrass habitat complexity on predation which have found predation to decrease with increasing density or complexity.In conclusion, I have sought to provide sound scientific information to aid in the management of these systems. A simple, but nevertheless key finding was that sponges and ascidians are indeed present and widespread in coastal lakes and lagoons of southeastern Australia and should not be continually overlooked in the management and conservation of these systems. Conservation will be complex and requires an understanding of environmental impacts and the consequences of management on the full range of biodiversity. The distributions of sponges and ascidians at large ‘lakewide’ scales appear to behave similarly to other taxa. Management strategies which change the characteristics of a lake at these large spatial scales such as artificial openings of entrances could therefore be predicted to have similar effects across a range of taxa including sponges and ascidians. In contrast, at smaller spatial scales such as the complexity of seagrass meadows, some species of sponges and ascidians may behave very differently from other taxa. At present, our understanding of these naturally variable and complex systems is incomplete and will require ongoing scientific investigation to identify natural patterns of distribution, environmental impacts, important natural processes and the ecological consequences of management strategies.
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André, Stéphane. "Caractérisation et écologie microbienne de lignes de production de conserves." Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS047/document.
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Si les flores contaminantes représentent la plupart du temps, dans les conserves, un risque industriel aujourd'hui maitrisé, la flore d'altération, de par sa résistance importante à la température, continue à constituer une cause de pertes économiques majeures. Pourtant cette dernière restait cependant peu caractérisée. En s'appuyant sur les travaux réalisés ces dernières années au sein de l'unité de microbiologie EMaiRIT'S du CTCPA (unité d'Expertise dans la Maitrise du Risque Industriel en Thermorésistants Sporulés du Centre Technique de la Conservation des Produits Agricoles), les principaux objectifs de cette thèse ont été (i) d'identifier et caractériser, en vue de sa maitrise ultérieure, la flore d'altération sporulante (ii) d'identifier l'origine de ces flores dans les conserveries et enfin (iii) de déterminer des moyens de maitrise.Pour cela, un état des lieux des bactéries sporulées d'altération des conserves a été effectué avec la collaboration de 122 conserveries sur plus de 10 ans en France. Cette caractérisation des espèces altérantes a permis l'élaboration d'un outil de biologie moléculaire (SporeTraQTM) afin d'identifier rapidement ces germes ou de pouvoir les détecter au sein d'une population complexe. En parallèle, l'amélioration de la connaissance de la thermorésistance de ces espèces, principale caractéristique de la flore sporulante, a été menée. A ce paramètre, il a été associé une relation avec la chimio résistance des spores. Identifiée, nous avons cherché à localiser cette flore d'altération au sein des usines à l'aide de plusieurs campagnes de prélèvements sur différents légumes. Au final, la flore spécifique du procédé de fabrication des conserves a été identifiée, caractérisée et localisée en vue d'améliorer la maitrise du risque microbien soit par une maitrise des contaminations et/ou un nettoyage plus performant (localisation au niveau d'étapes unitaires, efficacité de molécules sporicides) soir par un barème optimisé (en relation avec la thermorésistance). De plus, ce travail a été conduit au sein d'une approche bénéfice/risque représentant le futur de l'évolution des procédés agro-alimentaires associant amélioration de la qualité nutritionnelle et maintien de la maitrise sanitaire. Cette thèse s'appuie sur 5 publications de rang AMicrobial contaminants of safety concern represent most of time, in canned food, an industrial risk which is well mastered. However, the spoilage flora, due to its high heat resistance, is responsible for major economic losses. Nevertheless, these bacteria remained poorly characterized. Based on the works realized during last 10 years within the EMaiRIT'S unit of microbiology of the CTCPA (expertise unit of the French Technical Center of the Preservation of Food, focused on Management of Industrial Risk liked to Heat Resistant Spores), the main objective of this thesis were: i) to identify and to characterize, with the aim of its later control, the spoilage spore forming bacteria florae ii) to identify the origin of these florae in canning factories and finally iii) to determine ways of control.For that purpose, a current inventory of spore forming bacteria in spoiled canned food was made with the cooperation of 122 canning factories over more than 10 years in France. This characterization of the spoilage species allowed the elaboration of a molecular biology tool (SporeTraQTM) for quick identification of these germs or their detection within a complex population. In parallel, the improvement of the knowledge about the heat resistance of these species, main characteristic of the spores, was led. In addition, the chemical resistance of spores was investigated. When identified, we tried to localize these spores on canning factories lines, with several sampling plans, on various vegetables. At the end, the specific spore forming bacteria related to the industrial canning process was identified, characterized and localized, allowing to improve the microbial risk control either by a more efficient cleaning, and through optimized process schedules. Furthermore, this work was driven within a benefic / risk approach representing the future of the food-processing evolution with improvement of the nutritional quality and the preservation of the sanitary control.This thesis leans on 5 publications of rank A
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Holmes, Katherine E. (Katherine Elizabeth). "The effects of eutrophication on clionid (Porifera) communities in Barbados, West Indies." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23896.
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Samples of Porites porites rubble were collected from across three fringing reefs which lie along a eutrophication gradient in Barbados, West Indies. The coral skeleton fragments were examined for clionid sponges. Data collected from the reef crest and fore reef zones and from across the range of distances and depths were pooled for each reef to compare indices of sponge abundance along the eutrophication gradient. Significant differences between the reefs were found for the proportion of rubble invaded (ANCOVA, p = 0.004), number of invasions per sample (ANCOVA, p = 0.002), and number of species per sample (ANCOVA, p = 0.018) but not for total surface area of sponge invasions per sample (ANCOVA, p = 0.064). All the indices demonstrated an increase with increasing eutrophication level. Clionids were found in nearly twice as many of the pieces collected from the most eutrophic site (41%) as from the least eutrophic (24%). Since clionids may be the principal bioeroders of coral reefs, an increase in their abundance due to excessive pollution likely results in greater bioerosion of affected reefs. The mean abundance of Type 3 corals was found to be positively related to the frequency of boring sponge invasion, suggesting that increased bioeroision may be partly responsible for community shifts toward Type 3 corals in polluted waters. One new variety and three new species of boring sponges of the genus Cliona were found. A new variety of C. amplicavata Rutzler is described, Cliona species 2 of MacGeachy is redescribed and Cliona species 4 and Cliona species 5 are described for the first time. Cliona species 5 may become an important bioeroder in Barbados and other Caribbean islands since it flourishes under high eutrophic conditions which are beginning to plague West Indian reefs. (Abstract shortened by UMI.)
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Helber, Stephanie [Verfasser], Claudio [Akademischer Betreuer] [Gutachter] Richter, and Peter [Gutachter] Schupp. "Chemical ecology of Western Indian Ocean reef sponges / Stephanie Helber ; Gutachter: Claudio Richter, Peter Schupp ; Betreuer: Claudio Richter." Bremen : Staats- und Universitätsbibliothek Bremen, 2016. http://d-nb.info/111775684X/34.
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Sniegula, Szymon. "Correlation between photoperiod and development rate in the damselfly Lestes sponsa (Hansemann) : A compensating mechanism across latitudes?" Thesis, Umeå University, Department of Ecology and Environmental Sciences, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-30010.
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Although there is much theoretical and empirical data about the life history responses of time constrained organisms, little is known about the latitude compensating mechanism that enables northern populations’ developmental rates to compensate for latitude. To investigate the importance of photoperiod on development and growth, I collected adults and raised the offspring of the obligatory univoltine damselfly Lestes sponsa from two populations at different latitudes (53º N and 63º N). The offspring were raised in a common laboratory environment at 21º C and at the two photoperiods corresponding to the sites of collection. Field data showed that adult and egg sizes decreased towards the higher latitude. This adult size difference was a genetically fixed trait since the same size difference between populations was also found when larvae where reared in the laboratory. All studied individuals expressed shorter development time and faster growth rates under northern photoperiod regimes. Northern damselflies showed fixed body size and mass at emergence despite being reared at different photoperiod conditions. Similarly, southern individuals kept body size at emergence constant at both photoregimes, but overcompensated shorter development time in the northern photoregime by gaining higher body mass than in original,southern photoregime. There was no difference in hatching synchronisation between larvae from the south and the north. I found evidence of higher synchrony at adult emergence among northern individuals. The previous investigation of L. sponsa phenology in natural conditions together with these laboratory results indicate the presence of the latitude compensating mechanism that is triggered by a response to photoperiod. A positive correlation between photoperiod and developmental rate in this damselfly, and probably in many other temperate insect species, might be adaptive since it optimises the life history stage transitions and body size/mass at each latitude.
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Ginn, Brian Kendell. "Ecology, systematics, and feeding rate of sponges on subtidal hard substrates in Little Letite Passage, Deer Island, New Brunswick." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq23799.pdf.
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Santos, Marina Fernandes Barbosa dos. "Predação, eutrofização e respostas metabólicas em comunidades incrustantes de substratos artificiais na Baía da Ilha Grande, RJ." Universidade do Estado do Rio de Janeiro, 2013. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=5153.
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Fundação de Amparo à Pesquisa do Estado do Rio de JaneiroAs comunidades marinhas são afetadas por diversos fatores, que dentro do contexto de estrutura trófica, podem ser divididos em forças bottom-up (forças ascendentes), como por exemplo, a disponibilidade de nutrientes, e forças top-down (forças descendentes), como por exemplo, a predação. Além de modificações na estrutura das comunidades e populações de organismos, essas forças podem influenciar a produção de metabólitos secundários pelos organismos. O presente trabalho teve como objetivo avaliar o efeito das perturbações ambientais geradas pelas manipulações separadas e interativas de exclusão de macropredadores e enriquecimento com nutrientes sobre a estrutura e sobre as respostas metabólicas de comunidades marinhas incrustantes de substratos artificiais no costão rochoso de Biscaia, Baía da Ilha Grande, RJ. O desenho experimental utilizou blocos de concreto como substrato artificial, os quais foram espalhados aleatoriamente na região de infralitoral do costão rochoso. O experimento compreendeu o uso de blocos Controle (ausência de manipulação) e quatro tratamentos, todos com cinco réplicas cada. Os tratamentos foram: tratamento Exclusão de predação (gaiola contra a ação de macropredadores), tratamento Nutriente (sacos de fertilizante de liberação lenta), tratamento Nutriente + exclusão de predação (gaiola contra ação de macropredadores e sacos de fertilizante de liberação lenta) e o tratamento Controle de artefatos (gaiola semifechada para avaliar geração de artefatos). Uma área de 15 x 15 cm do bloco foi monitorada a cada 20 dias, totalizando dez medições. Foram utilizados métodos de monitoramento visual e digital de porcentagem de cobertura por espécie. O enriquecimento com nutrientes foi avaliado através de medições da concentração dos nutrientes Ortofosfato, Nitrato, Nitrito e Amônio na água do entorno do bloco. Para analisar os possíveis artefatos foi realizado experimento de fluxo de água (método Clod card) e a luminosidade dentro das gaiolas foi medida. Os dados demonstraram modificações na estrutura das comunidades bentônicas incrustantes dos substratos artificiais devido às manipulações realizadas, ou seja, pelo enriquecimento com nutrientes, pela exclusão de predação e pela interação entre os dois fatores (Nutriente + exclusão de predação). Além disso, diferenças metabólicas foram detectadas nas substâncias extraídas dos organismos dos diferentes tratamentos do experimento. Esses resultados indicam a existência de controle top-down e bottom-up sobre a comunidade bentônica do local.
Marine communities can be affected by many factors. Within the context of trophic structure, these factors can be divided into bottom-up forces, such as nutrient availability, and top-down forces, for example, predation. In addition to changes in the structure of communities and populations of organisms, these forces can influence the production of secondary metabolites. This study aimed to evaluate the effect of environmental perturbations generated by separate and interactive manipulations of macropredators exclusion and nutrient enrichment on the communitys structure and the metabolic responses of marine fouling communities of artificial substrates in Biscaia rocky shores, Ilha Grande Bay, RJ. The experimental design used concrete blocks as artificial substrate. The blocks were randomly scattered in the sub tidal region of the rocky shore. The experiment involved the use of Control blocks (no manipulation) and four treatments with five replicates each. The treatments were: Predator Exclusion treatment (cages excluding macropredators), Nutrient treatment (packs with slow-releasing fertilizer), Nutrient + predator exclusion treatment (cage excluding macropredators and packs with slow-releasing fertilizer), and Artifacts control treatment (semi-closed cage to assess artifacts effects). An area of 15 x 15 cm of each block was monitored every 20 days, totaling ten measurements. Visual and digital species percentage coverage methods were used. To assess nutrient water enrichment, we measured concentration of nutrients (orthophosphate, nitrate, nitrite and ammonium) in the water. To evaluate possible cages experimental artifacts, a water flow test (Clod card method) was performed, and luminosity inside the cages was measured. Data demonstrated changes in the structure of fouling communities on artificial substrates due to the manipulations performed, i.e., the nutrient enrichment, predation exclusion and the interaction between these two factors (Nutrient + predator exclusion). Moreover, differences were observed in substances extracted from organisms in different treatments of the experiment. These results indicate the existence of top-down and bottom-up controls on the benthic community of this site.
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Bigley, Christopher T. "Multi-Locus Evidence of a Late Pleistocene Divergence and Sex-Biased Dispersal in The North American Wood Duck (Aix Sponsa)." Wright State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=wright1323883896.
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Morganti, Teresa Maria. "In situ direct study of filtration and respiration rate of Mediterranean sponges = Estudio in situ de la filtración y la respiración de esponjas mediterráneas." Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/397747.
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Sponges play important roles in the functioning of marine ecosystem in which they are abundant. These roles range from stabilizers of substrate, to acting as major link between benthic and pelagic realms by filtering large quantities of water and retaining the particles with high efficiency. Despite sponges have been the focus of much interest in the past years our knowledge on sponge physiology is still poorly understood. This study focused on ecophysiology of five of the most prominent sponge species dwelling the coralligenous community in the NW Mediterranean Sea, and employed an energetic approach to understanding the complex interactions between physiological constrains and seasonal fluctuations of environmental factors experienced by the organism under natural conditions. In this thesis, we contributed to the still limited knowledge of energetic mechanisms that regulate seasonal dynamics and elucidated divergent metabolic profiles between high microbial (HMA) and low microbial (LMA) abundance species accordingly to their different adaptive life strategies. For this purpose we examined the in situ feeding, filtering and respiration activity over annual cycle. Firstly, we started by developing a system for quantifying the particulate and dissolved compounds processed by sponges under natural conditions. In terms of feeding, we observed that all species retained plankton at high efficiency and DOC was the main source of carbon. However, the nitrogen fluxes showed a marked different trophic niche between the two groups: HMA species mostly relied on dissolved compound as main source of N, while LMA solely relied on particulate fractions. Interestingly, natural variation of sponge pump did not follow natural temperature changes. During the period of maximum temperature the sponge pump did not reach its maximum values, suggesting that intrinsic mechanism as a decrease in choanocytes during reproductive cycle may regulate this metabolic process. On the other hand respiration clearly showed a seasonal pattern following natural temperature fluctuation. Combined, these results allowed us to estimate the overall energy budget, which appeared to be regulated by an increase of energy demand in summer as well as the availability of dissolved organic carbon fraction in the water column. Our result also showed different limited energetic profiles between HMA and LMA species accordingly to their different feeding strategies. LMA species appeared to procure sufficient energy to meet metabolic requirements for maintenance and growth by filtering suspended particulates, and dissolved fraction represented an additional input of carbon when available. On the contrary the heterotrophic nutrition in the natural environment may be insufficient to meet basal metabolic requirements in HMA species, suggesting other metabolic pathways as relevant for the energy budget of these species.Les esponges juguen un paper important en el funcionament del ecosistemes marins on hi son abundants. Les funcions atribuïdes a les esponges son molt diverses i inclouen entre altres actuar com estabilitzadores del substrat, així com fer de lligam entre la columna d'aigua i el bentos en l'anomenat acoblament bento-pelàgic; aquest procés te lloc mitjançant una captura eficient de partícules i el retorn de compostos modificats per l'activitat metabòlica de les esponges. Tot i que les esponges han estat punt de mira en l'interès científic durant els darrers anys, s'identifica encara una manca de coneixement de la seva fisiologia. Aquesta tesi es centra en l'ecofisiologia de cinc especies d'esponges emblemàtiques del coral·ligen Mediterrani. Utilitzant una aproximació energètica s'ha avaluat les interaccions entre possibles limitacions fisiològiques en les esponges i fluctuacions estacionals en els paràmetres ambientals a les que estan sotmeses en la natura. En aquesta tesi contribuïm al coneixement encara limitat dels mecanismes energètics que regulen la dinàmica estacional de les esponges així com en aportar informació sobre el perfils metabòlics divergents entre les esponges amb alta (HMA) i baixa (LMA) concentració de microbis associats segons les seves diferents estratègies adaptatives. Amb aquest objectiu examinem in situ l'alimentació, la filtració i la respiració al llarg d'un cicle anual. En primer lloc comencem desenvolupant un sistema que permeti la quantificació de compostos particulats i dissolts processats per les esponges en el seu habitat natural. En termes d'alimentació hem observat que totes les especies retenen molt eficientment el plàncton i que el carboni orgànic dissolt (DOC) es la seva principal font de carboni. Respecte als fluxos de nitrogen s'ha trobat diferents nínxols tròfics entre especies amb diferent concentració de microbis associats: especies HMA depenen bàsicament de compostos dissolts com a font de nitrogen mentre que les especies LMA depenen de la fracció particulada. Curiosament, la variació en la tassa de filtració al llarg de l'any no segueix el cicle de temperatura. El període de temperatura mes alta no va coincidir amb les tasses de filtració mes elevades suggerint que altres mecanismes intrínsecs a les esponges, com pot ser una disminució en la quantitat de coanòcits durant el cicle de reproducció, podrien regular el metabolisme de les esponges. Per altra banda la respiració ha mostrat un patró estacional seguint les fluctuacions naturals de la temperatura. La combinació d'aquests resultats ens ha permès estimar el balanç energètic global, aquest sembla estar regulat per un increment en la demanda energètica a l'estiu coincidint amb un increment en la disponibilitat de carboni orgànic dissolt en la columna d'aigua. Els nostres resultats també han mostrat diferencies en el perfil de limitació energètica entre especies HMA i LMA coincidint amb les seves diferents estratègies en la captura de nutrients. Les especies LMA sembla que obtenen suficient energia per cobrir el seu metabolisme a partir de la matèria particulada de l'aigua, essent la fracció dissolta un aportació addicional de carboni. Contràriament en especies HMA la nutrició heterotròfica sembla ser insuficient per cobrir els requeriments metabòlics basals suggerint altres vies metabòliques rellevants per cobrir el balanç energètic.
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Wedén, Christina. "Black Truffles of Sweden : Systematics, Population Studies, Ecology and Cultivation of Tuber aestivum syn. T. uncinatum." Doctoral thesis, Uppsala universitet, Systematisk botanik, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4675.
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Tuber aestivum is an ectomycorrhizal ascomycete with underground fruit bodies. It is an economically important species, but has been regarded as endangered in Sweden. My inventory has increased the number of reported localities from 3 to 31. It has long been debated whether T. aestivum and T. uncinatum are conspecific or not, so a clarification would help conservation biology and cultivation. My study included 117 fruit bodies of both taxa from 8 countries. The phylogenetic (ITS) and microscopic analyses showed that the two taxa were synonyms and that the spore reticulum height, used to separate the taxa, is not diagnostic. T. aestivum was clearly different from T. mesentericum, which I reported new to Sweden. The Gotland T. aestivum population was genetically distinct (RAPD) from other European specimens. The genetic variation suggested sexual reproduction. The habitat of 18 T. aestivum sites on Gotland were analysed and compared with data from France. No striking functional differences in soil chemistry were found, so a possible T. aestivum ecotype on Gotland would rather be an adaptation to the colder and drier climate. Selecting local T. aestivum inoculum for truffle orchards in Northern Europe could be important for successful truffle production. In 1999, 10 experimental truffle orchards with a total of 240 oak and hazel seedlings were established on Gotland, and as a result of this project 3000 commercial oak seedlings were planted in 2000-2001. In 2004, T. aestivum mycorrhiza was still present in all of the 22 orchards studied on Gotland, some in soils different from natural habitats. In addition, the project has also generated a truffle cultivation association, a truffle company, truffle dog breeding and export of T. aestivum to France.
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Nyberg, Kruys Åsa. "Phylogenetic relationships and species richness of coprophilous ascomycetes." Doctoral thesis, Umeå University, Ecology and Environmental Science, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-625.
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Coprophilous ascomycetes are a diverse group of saprobes, of which many belong to three families, Delitschiaceae, Phaeotrichaceae and Sporormiaceae, within the large order Pleosporales. The natural relationships and circumscription of these families are unclear, especially within the family Sporormiaceae, where the generic delimitation have been questioned. There is also a need to understand how different ecological processes affect species richness and occurrence of coprophilous ascomycetes in general. The aim of this thesis was therefore to test earlier classifications of coprophilous taxa within Pleosporales, using phylogenetic analyses of DNA sequences; and to study how the habitat, dung type and herbivores´ food choice may affect the species richness and species composition of coprophilous ascomycetes.
A phylogenetic study shows that coprophilous taxa have arisen several times within Pleosporales. Sporormiaceae and Delitschiaceae are separate monophyletic groups and should continue to be recognized as two distinct families within Pleosporales. Phaeotrichaceae forms a monophyletic group, and is, unexpectedly, a strongly supported sister-group to Venturiaceae, but if they belong to Pleosporales or not, remains unresolved. Testudinaceae and Zopfiaceae, which previously had an unclear position in Ascomycota, are shown to be members of Pleosporales and should be treated as two separate families. The genus Eremodothis is, however, not related to Testudinaceae, but is nested within Sporormiaceae and should be transferred to Westerdykella.
The natural relationships within Sporormiaceae are still not fully resolved and consequently, I suggest a rather conservative generic classification, accepting Preussia, Sporormia, Westerdykella, as well as Sporormiella, despite that the latter is not conclusively well supported as monophyletic. Characters previously used in the taxonomy and classification of Sporormiaceae, as choice of substrate, presence or absence of an ostiole, presence or absence of germ slits, and spore ornamentation, were all homoplastic and not very useful for circumscribing monophyletic groups.
Field-studies of moose (Alces alces), mountain hare (Lepus timidus) and roe deer (Capreolus capreolus) dung resulted in several new species records, which suggests that coprophilous ascomycetes in boreal Sweden are poorly known. Fungal species richness and occurrence on moose dung varied significantly between habitats. Species diversity was negatively associated with amount of insect attack, and insects feeding either on the dung and/or the fungi may be an important factor explaining the observed pattern. Species richness of coprophilous fungi varied also significantly between different dung types. A study of moose, mountain hare, and roe deer dung did not show any consistent patterns in respect to the animals´ digestive system. There was, however, a general strong positive relationship between the total number of ascomycete species and the number of plant species foraged by the three herbivores. Fungal species with large spores (≥ 50 µm) were over-represented on roe deer dung, and under-represented on moose dung, while the reverse was found for species with small spores (<10µm). This suggests that the foraging level of the herbivore, which in turn mirrors species-specific differences in spore dispersal of the fungi, may be an important factor in explaining species richness and diversity of the coprophilous community.
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Cohen, Staci Padove. "Functional identification and initial characterization of a fish co-receptor involved in aversive signaling." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29677.
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Thesis (Ph.D)--Biology, Georgia Institute of Technology, 2009.Committee Chair: McCarty, Nael A.; Committee Co-Chair: Kubanek, Julia; Committee Member: Derby, Charles; Committee Member: Goodisman, Michael; Committee Member: Pardue, Machelle; Committee Member: Weissburg, Marc. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Ivanisevic, Julijana. "Metabolisme secondaire des éponges Homoscleromorpha : diversité et fluctuation de son expression en fonction des facteurs biotiques et abiotiques." Thesis, Aix-Marseille 2, 2011. http://www.theses.fr/2011AIX22034.
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Le métabolisme secondaire joue un rôle écologique majeur dans les interactions des organismes avec leur environnement. Une étude intégrée de la biologie, de l’écologie des organismes et des variations de leur métabolisme est essentielle pour comprendre le rôle des métabolites secondaires au sein des écosystèmes. Or ce type d’approche est rare en milieu marin.Le petit clade d’éponges Homoscleromorpha constitue un vrai potentiel de découverte de nouvelles espèces et de molécules bioactives valorisables. Par ailleurs, leur position de dominance dans certaines communautés benthiques de Méditerranée en faisait un modèle de choix pour démarrer des recherches en écologie chimique marine.Ce travail a débuté avec la description d’une espèce du genre Oscarella, O. balibaloi ainsi que de nouvelles molécules produites par cet organisme. Cette nouvelle espèce avec deux autres espèces communes du même genre, O. tuberculata et O. lobularis constituent parfois de vrais faciès au sein des communautés du coralligène et des grottes semi-obscures. L’étude comparée du cycle de vie de ces Oscarella a montré dans tous les cas une reproduction saisonnière, avec des différences dans les périodes de gamétogénèse et d’émission des larves, et des sensibilités variables face aux changements des conditions de régime thermique. Deux composés majoritaires de type lysophospholipides ont été isolés et caractérisés pour la première fois dans O. tuberculata, et retrouvés dans O. lobularis. Leur rôle potentiel de médiateurs moléculaires impliqués dans le processus de reproduction (embryogenèse et développement) a été proposé, et devra être confirmé par des études expérimentales. Une nouvelle famille de sesterterpènes glycosylés (dénommés balibalosides) a été découverte dans O. balibaloi.Une étude pluriannuelle des variations du métabolisme de ces espèces a été réalisée à travers trois approches complémentaires permettant de tester les modalités d’allocation des ressources à la production de métabolites secondaires. Les patrons de variation des niveaux d’expression de métabolites ciblés, des signatures métaboliques et des bioactivités des extraits d’éponges ont montré une influence significative du cycle de reproduction sur le métabolisme secondaire. Les méthodes globales (métabolomique et bioactivité) ont permis de montrer que le cycle de variation du métabolisme secondaire était marqué par une modification importante de sa production accompagnée par une baisse de bioactivité pendant les périodes les plus coûteuses de la reproduction (reproduction asexuée, embryogenèse et développement larvaire). Ces résultats montrent un compromis d’allocation des ressources entre un métabolisme primaire (la reproduction) et la production des métabolites secondaires, et soutient ainsi la théorie de défense optimale.L’approche de métabolomique s’est avérée un bon indicateur de la chimio-diversité. Appliquée à l’étude des relations inter-spécifiques, cette méthode de chimio-systématique a permis de proposer une classification des espèces méditerranéennes d’Homoscleromorpha. Cette classification soutient les résultats les plus récents de phylogénie moléculaire et propose la restauration de deux anciens clades au sein des Homoscleromorpha: les Plakinidae, un groupe qui ne contient aujourd’hui que des espèces à squelette, et les Oscarellidae qui ne contient que des espèces sans squelette. Les approches développées au cours de cette thèse permettent de nombreuses perspectives en chimio-systématique et écologie chimique marine. L’utilisation des signatures métaboliques peut être transposée à d’autres questions de systématique, particulièrement pour démontrer l’existence d’espèces cryptiques, et pour soutenir des hypothèses phylogénétiques au sein d’autres clades problématiques [...]Secondary metabolism plays a major ecological role in the interactions between the organisms and their environment. An integral study of the organisms’ biology and ecology and the variations of their metabolism is essential for understanding the role of secondary metabolites in the ecosystems. This kind of approach is rare in the marine environment. Small sponge clade Homoscleromorpha constitutes a real potential for the discovery of new species and potentially bioactive molecules. In addition, its dominance in some Mediterranean benthic communities makes it a good model in marine chemical ecology research. This work has started with a description of new species of Oscarella genus, O. balibaloi. This new species forms sometimes, with two other commun Oscarella species, O. tuberculata and O. lobularis, special facies within the coralligenous and semi-dark cave communities. All three Oscarella species are caraterized by a seasonal reproductive cycle with differences in the period of gametogenesis and larval emission as well as the variation in sensitivity facing the changes in thermal regime. Two major lysophospholipid compounds were isolated and caracterized for the first time in O. tuberculata and confirmed in O. lobularis. Their potential role as signal molecules in the reproduction process (embryogenesis and development) was proposed and should be confirmed by experimental studies. One new familly of glycosilated seterterpens (named balibalosides) was found in O. balibaloi. A pluriannual study of species metabolism was performed using three complementary approaches and enabled to test the models of resource allocation to secondary metabolite production. Variation patterns in the expression level of target metabolites, in the metabolic fingerprints and the bioactivities of sponge extracts reflected the significant influence of the reproductive cycle to the secondary metabolite production. Holisitic approaches (métabolomics and bioactivity) pointed out the important modification in the secondary metabolism variation pattern followed by the decrease in bioactivity during the costly period of reproduction (asexual reproduction, embryogenesis and larval development). These results highlight the trade-off in resource allocation between the primary (reproduction) and secondary metabolism and therefore support the Optimal Defense Theory. Metabolomic approach applied to the study of interspecific relations turned out as a good indicator of chemical diversity which allowed the classification of Mediterranean Homoscleromorpha sepcies. The obtained classification was congruent with recent molecular phylogeny results proposing the restauration of two ancient clades within Homoscleromorpha, the Plakinidae, a group of species possesing skeleton and the Oscarellidae, a group of species lacking skeleton. Approaches developed during my thesis opened a numerous perspectives in chemosystematics and marine chemical ecology. The use of metabolic fingerprints can be transposed to other questions in systematics, particularly to demonstrate the existance of cryptic species and to support phylogenetic hypothesis within other problematic clades. [...]
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Fortunato, Humberto Freitas de Medeiros. "Biodiversidade e dinâmica estrutural de assembleias de esponjas marinhas (Filo Porifera) da Ilha Grande e cercanias, Rio de Janeiro, Brasil." Universidade do Estado do Rio de Janeiro, 2015. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=9043.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorEstudos de comunidades de esponjas marinhas são escassos no Brasil, sendo este trabalho pioneiro nessa abordagem para a Ilha Grande - RJ, um local de alta diversidade biológica. A estrutura das assembleias de esponjas marinhas e da comunidade bentônica marinha séssil foi avaliada, a partir de índices descritores de diversidade, em seis pontos da Ilha Grande e ilhas próximas, sendo três do lado continental e três do lado oceânico. As assembleias foram comparadas entre os diferentes lado e profundidade, através da contagem do número de indivíduos e área de cobertura por foto-quadrados. Paralelamente, as esponjas foram coletadas, fixadas e posteriormente identificadas através de metodologia e literatura especializada. Foi encontrado um total de 5.457 indivíduos, representando as Classes Demospongiae e Calcarea, distribuídos em 41 espécies e nove morfotipos, indicando maior diversidade para Lagoa Azul e menor para Parnaióca, sendo o local com maior riqueza a Ilha do Abraão. Dentre as espécies identificadas, quatro dominaram mais de 50% do total e 26 não alcançaram nem 5% da abundância absoluta. Análises de variância por GLM só evidenciaram diferença significativa para profundidade com substratos diferentes (F= 2,79; p<0,04), enquanto o fator lado (F= 2,23; p>0,16) e a interação entre os fatores (F= 1,17; p>0,38) não tiveram diferença estatística. As análises multivariadas de ordenação Cluster e MDS indicaram a formação de quatro assembleias de esponjas: 1) quatro locais com substrato não consolidado; 2) Lagoa Azul com substrato não consolidado; 3) locais oceânicos de substrato rochoso; e 4) locais continentais de substrato consolidado. Já para a comunidade geral, 49 espécies foram encontradas, sendo o Filo Porifera o de maior representatividade específica, apesar das macroalgas terem formado o grupo mais abundante. A comunidade bentônica foi dominada por quatro espécies, que juntas alcançaram média de 50% da cobertura bentônica: alga calcária incrustante, algas formadoras de tapete de turf, a esponja Iotrochota arenosa e o zoantídeo Palythoacaribaeorum. Estatisticamente, o lado continental se mostrou diferente do oceânico, o qual possui maior riqueza, diversidade e uniformidade de espécies, muito provavelmente pelo menor número de espécies dominantes e aliado a isso maior heterogeneidade de habitats, o que promove o aumento da diversidade. Quinze novas espécies estão sendo registradas para a Baía da Ilha Grande, sendo três novas espécies, as quais estão sendo descritas por especialistas, e 12 são novos registros de espécies ou gêneros para a região, evidenciando que a diversidade de esponjas marinhas na BIG é alta e ainda pouco conhecida e que a formação de assembleias pode ser devida a singularidade de cada local, implicando na necessidade de conservação dos costões rochosos da Ilha Grande e cercanias, a qual pode ser manejada através da realização de rápidos levantamentos sobre a riqueza e o número de indivíduos da espécie na região
Marine sponge community studies are scarce in Brazil and this is a pioneering study in this approach on Ilha Grande RJ, a high diversity region. The structure of marine sponges assemblages and sessile marine benthic organisms was evaluated from diversity descriptors index in six sites of Ilha Grande and nearby islands, three in continental side and three on oceanic side. Assemblages were compared between sides and depths counting number of individuals and its coverage area by photo-quadrats method. At the same time, the sponges were collected, fixed and, in lab, identified through specialized methodology and literature. There was a total of 5.457, representing Class Demospongiae and Calcarea, distributed in 41 species and nine morphotypes (50 possible species) with greater diversity to Lagoa Azul on the inside and lower for Parnaióca, outside, while Ilha do Abraão had the greatest richness. Among the identified species, four dominated more than 50% of the total and 26 did not reach even 5% of total abundance. General linear model (GLM) on ANOVA highlighted significant difference only between depths with different substrates (F=2.79; p<0.04), while side (F=2.23; p>0.16) and the interaction between factors did not have differences (F=117; p>0.38). Ordination multivariate analyses, Cluster and MDS, distinguished four sponge assemblages: 1) four sites with unconsolidated substrate; 2) Lagoa Azul with unconsolidated substrate; 3) oceanic sites with hard substratum; 4) continental sites with hard substrate. For the community, 49 species were found and Phylum Porifera was the highest specific representation, despite macroalgae have formed the most abundant group. Encrusting calcareous algae, turf algae, sponge Iotrochotaarenosa, exclusive of the continental side and zoanthid Palythoacaribaeorum added approximately 50% of the benthic cover in all sites. The sides were significantly different with highest richness, diversity and evenness for oceanic side while continental had more abundance of species, most probably due to fewer dominant species. Moreover, greater heterogeneity of habitats may promote increased diversity. The 15 new species now recorded which three are new for science and 12 represent new species or genus records for Ilha Grande Bay revealing this area as one of the highest diverse area in marine sponges from Brazil, despite the low knowlegment. Furthermore, this result implies the need to increase the preservation of the rocky shores of the region and shows that a quick survey of the number of species and their abundance is sufficient to manage a conservation area
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Skelton, James. "Evaluation of the trophic ecology of a freshwater sponge and two sponge predators." 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1470427.
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Rickborn, Alissa Jean. "The spatial ecology of a coral reef sponge, aplysina fistularis." Thesis, 2014. https://hdl.handle.net/2144/15273.
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Sessile communities provide an ideal opportunity to understand how population interactions are structured in space, and in turn, how this structure influences population dynamics. The yellow tube sponge, Aplysina fistularis is common on Caribbean coral reefs and is involved in four main types of ecological interactions: symbiosis, predation, disease, and competition. We used spatial and multivariate analysis to describe the population structure of A. fistularis on the Belizean barrier reef, and consequently, how the observed spatial structure influenced sponge morphology and the frequency of population interactions. We found that sponges were non-randomly distributed across the reef, with both local density and tendency towards a clustered spatial distribution increasing with depth. Sponge morphology also varied with depth; deeper sponges were larger and had fewer tubes then their shallower conspecifics. Local density and spatial autocorrelational patterns were not significant predictors of population interactions. The frequency of symbiosis, characterized by the presence of the fish Elacatinus lori, increased with depth, sponge size, and number of sponge tubes. The incidence of predation increased with depth, number of tubes, and the interaction between these two variables. The chance of disease decreased with increasing sponge size. Lastly, the frequency of spatial competition decreased with depth. These results highlight the unexpected finding that in this system, symbiosis, predation, disease, and competition, are density independent, specifically they are not predicted by local density or spatial autocorrelational patterns. Overall, this study provides an essential framework that will greatly enhance our knowledge of sponge ecology on coral reefs.
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Bannister, Raymond. "The ecology and feeding biology of the sponge Rhopaloeides odorabile." Thesis, 2008. https://researchonline.jcu.edu.au/5667/1/01_front.pdf.
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On large coral reef systems like the Great Barrier Reef, with a significant cross shelf component throughout most of its length, sponges inhabit a broad range of benthic habitats, from shallow water turbid coastal reefs to clear water oceanic reef systems. The structure of sponge assemblages differs taxonomically and morphologically across these varied benthic habitats, responding to environmental conditions and reflecting the prevailing biophysical character. Despite these differences sponges as a group constitute a critical component of the benthos across all these habitats, providing structural rigour, and contributing to benthic-pelagic nutrient fluxes. Sponges also provide a substrate for the settlement and refuge of other benthic organisms and are a host to a large diversity and biomass of symbiotic microorganisms. Despite the importance of sponges within these habitats our understanding of population distributions and the key environmental parameters that influence and maintain them is in its infancy. This knowledge is fundamental to conservation and management of marine benthic environments.
The abundance, size and depth distribution of the sponge Rhopaloeides odorabile was quantified within inner-, mid- and outer-shelf reef locations across the continental shelf of the central Great Barrier Reef (GBR), Australia using belt transects. There was a clear gradient in the abundance, size and depth distribution of R.odorabile across all reefs sampled, with mean abundances on mid- (20.3 ± 2.2 individuals.250 m-2) and outer-shelf reefs (22.6 ± 6.4 individuals.250 m-2) being more than three times greater than inner-shelf reefs (6.2 ± 2.4 individuals.250 m-2). In addition, although not statistically different, the mean size of R.odorabile on outer-shelf reef locations (4236.3 ± 941.9 cm3) were larger than R.odorabile on inner- (3096.3 ± 1394.2 cm3) and mid-shelf reef locations (2323.8 ± 548.3 cm3), with R.odorabile preferring to inhabit deeper habitats on mid- and outer-shelf reef locations (8 to 12 m) than inner-shelf reef locations (<8 m). These distinct differences between shelf locations may be driven by differences in environmental gradients across shelf locations, in particular light availability, sedimentation and food availability.
Variation in light, sediment and food are key factors structuring the distribution, abundance and physiology of many sessile marine invertebrates in benthic habitats, particularly those harbouring symbiotic (possibly phototrophic) microbial symbionts. Photophysiology results for R.odorabile individuals from inner-, mid-, and outer-shelf reef locations, demonstrate that light availability does not physiologically regulate the size and depth distributions of R.odorabile across shelf locations. Photophysiology experiments identified that regardless of their origin, R.odorabile individuals collected across inner-, mid-, and outer-shelf reef locations did not photosynthesise or possess any photopigments. Therefore, R.odorabile does not acquire energy requirements by way of photosynthesis, showing that in terms of energy acquisition light availability does not influence size and/or the depth distribution of R.odorabile across shelf locations.
To quantitatively determine the impact of sedimentation and the role of sediment grain size and mineralogy on the ecology and physiology of R.odorabile, suspended sediment was sampled monthly across winter (Austral tropical dry season) and summer (Austral tropical wet season) at different locations including Pelorus Island (inner-shelf reef), Rib Reef (mid-shelf reef), and Pith Reef (outer-shelf reef). Regardless of month sampled, up to 32% of the volume of sediment on inner-shelf reefs was dominated by fine clay sediments (mean grain size 24.4 ± 5.7 μm), in contrast to mid and outer shelf reefs where less than 3% of the volume of sediments were fine clay sediments and instead sediments are dominated by coarse biogenic materials (mean grain sizes of 126.6 ± 30.5 μm and 214.3 ± 33.4 μm, respectively) (carbonate sediments). Decreasing sediment grain size and increasing clay content of suspended sediments towards the coast corresponded with the decreasing abundance, size and reduced depth distribution of R.odorabile towards the coast.
Food availability and the retention efficiency of ultraplankton cell types <3 μm were quantified for R.odorabile across inner-, mid- and outer-shelf locations. Across these shelf locations, R.odorabile was exposed to a broad range of ultraplankton cell types, including heterotrophic bacteria, Prochlorococcus spp., Synechococcus – type cyanobacteria and picoeukaryotes <3 μm. Food availability was more abundant on inner-shelf locations than outer-shelf locations, including picoeukaryotes <3 μm, the main planktonic food source for R.odorabile. Picoeukaryotes were retained preferentially with high efficiencies and these efficiencies are consistent across shelf locations (inner-shelf, 95%; mid-shelf, 87%; outer-shelf, 92%). Given the higher abundance of picoeukaryotes <3 μm on inner-shelf reefs, R.odorabile at these reefs assimilated 1.5 times more carbon (8.38 ± 0.10 μg C.l-1) and nitrogen (1.34 ± 0.02 μg N.l-1) than on mid-shelf reefs (5.23 ± 0.84 μg C.l-1, 0.84 ± 0.13 μg N.l-1), and 3 times more carbon and nitrogen than outer-shelf reefs (2.71 ± 0.90 μg C.l-1, 0.44 ± 0.15 μg N.l-1). Paradoxically, R.odorabile retains significantly more carbon and nitrogen in the form of picoeukaryotes on inner-shelf reefs than mid- and outer-shelf reefs, however, R.odorabile are not larger or more abundant on inner-shelf reefs. This may be explained by a metabolic ‘trade-off’ from increased energetic costs for R.odorabile living in high sediment inshore environments exposed to fine clay sediments.
Experimental manipulation of sediment grain size and mineralogy on the respiration rate of R.odorabile demonstrated unequivocally that fine clay sediments (mean grain size 3.1 ± 0.1 μm) increase the respiration activity from baseline respiration rates by 35% during short-term exposure (7 hours) and up to 43% during long-term exposure (4 days). Visual observations also identified that exposure to fine clay sediments induce the production of mucus on the external surfaces of R.odorabile, whilst the shutdown of sponge oscula was also evident. Therefore, exposure of R.odorabile on inner-shelf reefs to fine clay suspended sediments that are absent on mid- and outer-shelf reefs increases their metabolic costs, which may be responsible for reduced abundance and sizes of R.odorabile on inner-shelf reefs. This suggests that inner-shelf reefs provide sub-optimal habitat conditions for R.odorabile. These higher energetic drains in inshore environments may result in energy normally utilised for growth and reproduction being diverted to maintenance and survival, resulting in lower reproductive output, smaller individuals and subsequently lower abundance. These findings highlight the importance of identifying the key environmental parameters linked with anthropogenic change on the dynamics and structure of an important component of the benthic community.
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Cook, Sarah Emily. "Ecology of the Hexactinellid sponge reefs on the western Canadian continental shelf." 2005. http://hdl.handle.net/1828/646.
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Wei, Kyo-Yen, and 魏國晏. "The Impact of a Coral-invading Sponge (Terpios hoshinota) on Coral Ecology: An Approach Using Scanning Electron Microscope." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/13966044673611867417.
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碩士大仁科技大學
生物科技研究所
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Terpios hoshinota is an encrusting sponge killing corals by growing over them. However, little is known about the interactions between two partners. Examining the Terpios-coral border with scanning electron microscopy (SEM) indicated at least three features displayed at the sponge front, including hairy tips, firm edge, and necrotic tissue. Almost all hairy tips were occupied with cyanobacteria, sponge tissue and spicules. Features of the Terpios-coral border exhibit no specificity to coral species, except for a hydrozoan coral Millepora exaesa displaying reversed growth over the sponge. Under SEM examination, several coral species defended themselves with nematocyst. But, in some cases such that on Isopora palifera, its nematocyst seemed not to retard the invasion of the Terpios. In summary, the exploitation for substratum by T. Hoshinota on coral does not always promise which is the winner. To grow, build clear border or retrogression by the Terpios may rely on the viable condition of both partners.
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Du, Preez Cherisse. "Resolving relationships between deep-sea benthic diversity and multi-scale topographic heterogeneity." Thesis, 2014. http://hdl.handle.net/1828/5828.
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Resolving diversity patterns and their underlying drivers has application for both ecological theory and ocean management. Because seafloor characteristics are often used to assess bottom habitat, I examined the relationship between deep-sea benthic (bottom-living) diversity and multi-scale topographic heterogeneity. Most work occurred on the Canadian Pacific continental shelf at Learmonth Bank with additional sites in Strait of Georgia (BC) and Gulf of Maine (Atlantic shelf). High-resolution species distribution and seafloor data were annotated from remotely operated vehicle benthic imagery surveys while large-scale seafloor data were derived from multibeam sonar.
New method development to address problems of current methods and to facilitate comparison among ecosystems is a major outcome. My new MiLS method (microtopographic laser scanning) can profile the deep seafloor at a resolution of ~1-2 cm with high accuracy and precision. I also developed a new ACR (arc-chord ratio) rugosity index as a measure of 3-D topographic heterogeneity that is simple, accurate and highly versatile.
Model systems and scales vary among my studies but results consistently yield a positive relationship between diversity and topographic heterogeneity and identify bottom hydrodynamics as an important underlying driver. Rockfish Sebastes spp. associate with higher seafloor rugosity non-randomly and select for deep-sea corals and sponges over inert substrata alone. Data indicate that degradation of biogenic structures is a long-term detriment to rockfish species. Gorgonian coral- and sponge-dominant biotopes strongly associate with a single substratum type. These relationships were used to map coral and sponge distributions. This work, which collectively adds new information on the ecological relevance and distribution of corals and sponges, is pertinent to the conservation and management of fish stocks and vulnerable marine ecosystems. Epibenthic community variables abundance, richness, and Shannon diversity positively correlated with both the local microtopographic heterogeneity on a scale of 10 m2 and with the surrounding regional large-scale topographic heterogeneity on scales of 25 to 250,000 m2. Relationships were strongest between epibenthic community variables and the largest scale rugosity and were used to generate and test predictive diversity models. Where management strategies rely on surrogate measures in data-poor areas, mapping benthic diversity using ACR rugosity will provide good indicators.
Although bottom hydrodynamics is consistently identified as an underlying driver of epibenthic patterns related to topographic heterogeneity, data suggest the nature of the relationship varies across spatial scales. At small scales, high topographic heterogeneity likely increases diversity by increasing the number of available niches (including hydrodynamic gradients; e.g., the abrupt vertical rugosity created by tall corals and sponges provides rockfish refuge from currents) while at large scales, high topographic heterogeneity increases local diversity less directly through distant hydraulic events that alter bottom flow hydrodynamics.Graduate
0329
0416
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cdupreez@uvic.ca
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Mercado, Molina Alex E. "Population ecology of the demosponge Amphimedon compressa /." 2007. http://grad.uprm.edu/tesis/mercadomolina.pdf.
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Kötter, Iris [Verfasser]. "Feeding ecology of coral reef sponges / vorgelegt von Iris Kötter." 2005. http://d-nb.info/975585738/34.
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[Verfasser], Yasman. "Structure elucidation, biological activity, and ecology of terpene isocyanides from Phyllidiid species (Nudibranchia) and their sponge preys from The Thousand Islands National Park, Indonesia = (Strukturelle Identifizierung, Biologische Aktivität, und Ökologie von Terpen-Isocyaniden aus Phyllidien (Nudibranchia) und ihren Beuteschwämmen aus Die Thousand Island [Islands] National Park, Indonesien) / vorgelegt von Yasman." 2006. http://d-nb.info/979729696/34.
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Battershill, Christopher. "Factors affecting the structure and dynamics of subtidal communities characterised by sponges." 1987. http://hdl.handle.net/2292/1740.
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Two subtidal reef communities characterised by sponges were examined to assess two distinct aspects of marine benthic community ecology which have not previously received much attention. The first study focused on the role of settlement events in the origin and maintenance of community structure and involved investigation of factors affecting dispersion, settlement and recruitment of sponge propagules. The second examined how natural gradients in ambient physical conditions, in the absence of disturbance, affected size structure and species interactions within the community. Settlement events were examined on a reef flat which was covered by a shallow sediment overlayer. The distribution and abundance of established sponges was found to be highly correlated with sediment regimes. The sponge community was shown to be stable over time and able to resist disturbance by storms because of the presence of turfing algae. Sponge settlement was inhibited by the sediment overlayer. Established sponges were found clumped into oblong groups orientated east-west and there were many instances where sponges were found closely associated. Adjacent areas were characterised by deeper unstable sediments and fewer sponges. Storms contoured sediments into ripples and scoured oblong east-west orientated patches of basal rock. Sediments were also sorted during storms such that particles of large grain size were left around the edges of ripples and over the scoured rock patches. The basal reef of both the stable and unstable areas was covered in a mosaic of encrusting algal and sponge species which tolerated the sediment overlayer. This assemblage was also exposed during storms. Sponges reproduced in a number of ways, but asexual propagules were the most successful. Sponges from several orders produced buds which developed in a complex manner. Buds adhered to rock and shell fragments of large size which acted as anchors, or attached to other buds irrespective of genotype. The change in weight and shape increased the likelihood that buds would gravitate into the scoured patches of basal rock. Bud loss off the reef was minimal. Buds were able to settle onto the basal rock patches and did so almost exclusively onto bare rock. A high degree of 'selectivity' of settlement site by buds was imparted by altering developmental rate during the settlement process in response to the substrate type. Polymastia granulosa buds exhibited an additional developmental sequence not previously reported for any colonial organism. Buds either settled directly in suitable conditions, or developed further along a different pathway. Buds which did not come into contact with basal rock elongated and appeared to be capable of digging into sediments. The elongated bud then broke up along its length into smaller particles, termed 'beads', which were capable of movement and invariably settled onto gravel fragments. Sponges were shown to settle onto scoured rock patches during storms and were eventually covered by sediments. Subsequent survivorship and recruitment depended species specifically on sediment depth and quality. Settlement patterns matched the observed dispersion patterns of established sponges and suggested a mechanism whereby the community had originated and how structure was maintained. These hypotheses were tested experimentally in situ and in the laboratory. The importance of asexual modes of reproduction, and settlement mediated by physical disturbance appears to be a common formula for recruitment by colonial marine organisms. Recruitment events were found to explain the distributional patterns of the established population. The structure of populations of thin encrusting species on vertical reef walls was examined in a novel manner whereby the mean size and density of individuals was quantified and related to gradients in the ambient physical environment. This was achieved by examining the benthic communities on a range of subtidal reef walls of uniform slope and aspect, but which were subject to natural gradients in physical conditions. The species composition of each of the six reefs studied was similar but the size structure of communties changed within each reef system in response to gradients in light intensity and water movement. Fish and urchin disturbance was shown to be unimportant and there was no indication that storms disrupted communities. The implications of changes in size structure of populations on interactions between component species in different ambient conditions were examined. The eastern wall of two cave, archway and open reef systems was surveyed according to a stratified sampling design where each reef was divided by depth and distance along the wall. Different taxonomic/morphological groups were found at particular positions on reef walls. Thin encrusting algal species were found to be one of the most abundant groups. It was assumed that the individual size of encrusting species at each wall position reflected long term ambient environmental conditions as well as the ability of each species to maintain itself against overgrowth by neighbours. By relating the population size structure of different taxa with indices for light intensity and water movement recorded at each wall position within each reef, it was shown that community structure varied markedly on the same reef wall as a function of ambient physical conditions. Changes in proportional species composition, notably from thin encrusting algal dominated assemblages to sponge characterised assemblages, with decreasing light intensity were accompanied by changes in the individual size structure of populations. At each wall position all species exhibited similar individual size. Individual size decreased and density of individuals of all species increased with decreasing light intensity. In conditions where light levels were not sufficient to support algae, individual size of encrusting fauna increased with increasing water movement. The implications of these observations on competitive interactions between encrusting species was examined. The outcome of competitive interactions between the same species was found to vary depending on wall position.
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Adeleye, Matthew A. "A multi-proxy paleoecological study of Anderson Fen, Central Vancouver Island, British Columbia, Canada." Thesis, 2018. https://dspace.library.uvic.ca//handle/1828/10211.
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A paleoecological study was carried out on a 4.7 m peat core from Anderson Fen on central Vancouver Island, using a multi-proxy approach. Pollen, non-pollen palynomorphs, and physicochemical analyses were used to document past vegetation, peatland developmental history, and carbon and nitrogen accumulation rates over the last 14,000 years. Lake sediment and aquatic plant remains at the base of the core indicate a shallow pond was present at the site after deglaciation. By ~11,700 calendar years before present (cal yr BP), the shallow pond became a herb-dominated wetland (marsh) through terrestrialization. Bog formation started around 10,500 cal yr BP with decreasing water levels, as indicated by high C:N, Sphagnum and fungal remains, and testate amoebae such as Archerella flavum and Heleopera. A fen developed by ~9400 cal yr BP with fluctuating water levels through the rest of Holocene. Carbon accumulation rates were highest towards the surface and during the early Holocene warm period, with an overall mean rate of 12.9 g/m2/cal yr, which is low compared to continental and northern peatlands. Pollen analysis reveals that non-arboreal communities dominated by Salix prevailed soon after deglaciation before the expansion of Pinus forests 13,200 cal yr BP. Pseudotsuga menziesii dominated forests between ~10,700 and 8400 cal yr BP under warm and dry conditions. Tsuga heterophylla rainforest was established by ~7000 cal yr BP under increasingly cool and wet conditions. Overall, Anderson fen and the surrounding area experienced major and rapid changes in environmental conditions and vegetation in response to climate change during the late glacial and early Holocene, while mid- to late Holocene changes have been more subtle and relatively gradual.Graduate
2020-10-25
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Putz, Annika [Verfasser]. "Secondary metabolites from marine sponges, with focus on the chemical ecology and biochemical characterisation of the stress induced biotransformation of Aplysina alkaloids = Sekundärmetabolite mariner Schwämme, mit Schwerpunkt auf der chemischen Ökologie und biochemischen Charakterisierung der stressinduzierten Biotransformation von Aplysina-Alkaloiden / vorgelegt von Annika Putz." 2009. http://d-nb.info/994615175/34.
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