Dissertations / Theses: 'ALGAL BIODIVERSITY'

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Nissimov, Jozef I. "Ecological and functional biodiversity in a marine algal-virus system : genotypes, phenotypes and their ecological significance." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/13776/.

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Coccolithoviruses are large dsDNA viruses infecting the cosmopolitan calcifying marine phytoplankton Emiliania huxleyi. Therefore they are instrumental components of algal bloom demise and thus agents contributing significantly to biogeochemical cycling in the oceans. Several coccolithovirus strains exist in culture and have been used so far to study the co-evolutionary arms-race between them and their unicellular host in naturally occurring or induced blooms in the North Atlantic Ocean and the fjords of Norway. However, little is known of their distribution in non-bloom conditions, their natural diversity in times of reduced infectivity rates, and the role of functionally important genes found in natural coccolithovirus communities. Even less is known about their genetic differences and the phenotypic consequences of these differences on their infection dynamics. Hence here a three dimensional approach was undertaken, during which the genomes of several coccolithovirus strains were analysed, their diversity in the global ocean characterised, and their phenotypic properties as seen from their infection dynamics with their host established. It was revealed that although coccolithoviruses share a common subset of core genes, they differ in a large proportion of their genomic material, as seen from the presence and/or absence of large sub-clusters of functionally unknown genes. Moreover, a gene that encodes for a phosphate scavenging mechanism (phosphate permease) was truncated from the genome of the Norwegian isolate EhV-99B1 but not from any other strain, while a gene encoding for the virulence factor sialidase was truncated only in the genomes of the English Channel strains isolated in 2001. The discovery of an additional gene that is potentially involved in the regulation of sphingosine and ceramide intermediates during the de novo virus encoded sphingolipid biosynthesis pathway was also intriguing, and the extent of gene homology to host genes (i.e. almost 13% of the analyzed genomes) highlighted the importance of horizontal gene transfer events in the co-evolution between algal hosts and their viruses. Secondly, it was established that virus competition over its resource, the host-cell, is fierce and that during host coinfection, some viruses (i.e. EhV-207) were superior to others (i.e. EhV-86) in their quicker utilisation of the host metabolic machinery and possibly shorter latency period within the infected cells. The biogeochemical and evolutionary implications of these distinct phenotypic properties are far reaching as in the environment there would be hundreds of different virus strains fighting over a few dominant hosts, with “losers” and “winners” coming and going from a particular niche, affecting the recirculation of nutrients and carbon at different rates. Finally, by community fingerprinting cococlithoviruses in the global ocean with phylogenetic markers (major capsid protein) and functional markers (serine palmitoyltransferase) it was discovered that the diversity of these viruses increase with depth, and that the 3D structure of the SPT protein (involved in the propagation of host cell death) differs among strains, dictated by a variant amino acid linker region between the two domains of the protein, LCB1 and LCB2, potentially influencing the efficiency of the virus encoded sphingolipid biosynthesis pathway. This study is an important first step in understanding the role of coccolithoviruses, their evolution, their functional characteristics, and the possible implications of the latter to biogeochemical cycling and global climate and primary production predictions. Articles: Draft genome sequence of the coccolithovirus EhV-84 / Josef I. Nissimov ... [et al.]. Standards in Genomic Sciences, v. 5 (2011), p. 1-11 and Functional inferences of environmental coccolithovirus biodiversity / Josef I. Nissimov ... [et al.]. Virologica sinica (2013), doi: 10.1007/s12250-013-3362-1 have been removed from PDF for the copyright reasons.

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Garvey, Alyssa. "Next-generation sequencing, morphology, and culture-based methods reveal diverse algal assemblages throughout the Florida springs." UNF Digital Commons, 2019. https://digitalcommons.unf.edu/etd/899.

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Algae are a group of highly diverse photosynthetic organisms found in variety of habitats. As the primary energy base in ecosystems, knowledge of the diversity and presence of certain algal lineages is paramount to our understanding of the trophic state of aquatic habitats. In recent years, the state of Florida has seen an increase of both marine and freshwater algal blooms. Similarly, filamentous algae have begun outcompeting vascular macrophytes throughout many of Florida’s springs as nutrient enrichment from anthropogenic sources increases. Traditionally, the Florida algal spring communities have been assessed using classic morphological methods, which may underrepresent the true biodiversity present. Therefore, the goal of this study was to conduct a more complete diversity assessment implementing next-generation sequencing techniques (NGS) with morphological analyses and culturing methods. While morphological methods identified a wide variety of algal taxa, belonging to 4 phyla (Bacillariophyta, Charophyta, Chlorophyta, and Cyanobacteria), next-generation sequencing techniques provided greater detail of the diatom community. This is particularly important as many diatom taxa are used as indicators of water quality. We noted discrepancies between these two methods, highlighting how NGS techniques may complement the use of morphological analyses when analyzing algal diversity in this system. Culturing methods also revealed the presence of two taxa new to science (Nodosilinea fontisand Brasilonema variegatus), indicating these springs may represent a potential source of novel cyanobacteria. Taken together, this study showcases Florida springs are rich in algal diversity and a combination of methods is required for more complete biodiversity assessments. Future studies implementing such methods will aid in the preservation and conservation of these ecosystems.

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Hallmann, Christine Verfasser], Thomas [Akademischer Betreuer] [Friedl, and Michael [Akademischer Betreuer] Hoppert. "Biodiversity of terrestrial algal communities from soil and air-exposed substrates using a molecular approach / Christine Hallmann. Betreuer: Thomas Friedl. Gutachter: Thomas Friedl ; Michael Hoppert." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2016. http://d-nb.info/108912368X/34.

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Verhulst, Stephanie. "Response of the Epiphytic Algal Communities to Experimentally Elevated Nutrient Levels in Intertidal Salt Marsh Habitats." UNF Digital Commons, 2013. http://digitalcommons.unf.edu/etd/435.

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Epiphytes are organisms attached to plants and are responsible for the majority of primary productivity in many aquatic systems. While epiphytes serve as a valuable food resource to herbivores, they may prove deleterious to the host plant by competing for light and nutrients, as well as increasing sheer stress. This study evaluated the impacts of nutrient additions, nitrogen and phosphorus, on the epiphytic algal community on Spartina alterniflora over the course of two growing seasons. Three nutrient treatments (N, P, and N+P) and one control treatment were placed in a salt marsh in the Tolomato River during the growing seasons of 2011 and 2012. To assess community development, we examined biomass, ash-free dry mass (AFDM), chlorophyll-a levels, cell counts, and community diversity by algal division. The nutrient additions did not significantly alter any of the measured parameters in either sampling year. However, the sampling month did have a significant (pa, and community composition. A total of 155 infrageneric taxa were identified. Biomass tended to be dominated by diatoms and red algae, while cyanobacteria were most abundant. In both years, biomass was highest in the spring with a second smaller pulse in the fall. Conversely, chlorophyll-a levels varied between the years and did not show the same monthly patterns as AFDM. A laboratory study subjecting S. alterniflora to the same nutrient additions also found no significant effects of increased nutrients, but did observe temporal changes in biomass and chlorophyll-a levels. Overall, epiphytic growth was not influenced by nutrient additions in this study suggesting that this and other similar salt marsh systems may be resilient to anthropogenic eutrophication. Instead, other factors, such as light and herbivory, likely played a key role in determining epiphytic algal growth and community composition.

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Turunen, J. (Jarno). "Responses of biodiversity and ecosystem functions to land use disturbances and restoration in boreal stream ecosystems." Doctoral thesis, Oulun yliopisto, 2018. http://urn.fi/urn:isbn:9789526217826.

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Abstract Streams and rivers have been extensively altered by humans. Channelization and land use have changed stream habitats and water quality with adverse effects on biota and ecosystem functions. Impacted streams have been targets for restoration, but there is considerable lack of understanding how streams should be restored in an ecologically effective way. In this doctoral thesis, I studied the impacts of channelization (for timber floating) and agricultural diffuse pollution on stream biota. I also studied the effectiveness of restorations of forestry impacted streams stressed by excessive sand sedimentation from catchment drainage. Finally, I also studied the effects of mosses, fine sediment and enhanced dispersal on stream macroinvertebrate communities and ecosystem functions. I found that channelization did not have effect on diatom, macrophyte, macroinvertebrate and fish assemblages, whereas diffuse pollution had strong effects, with no interactions between the two stressors. I showed that excessive sedimentation from forest drainage was harmful for stream biota but had no effect on leaf decomposition and algal accrual rate. Restoration with boulders reduced sand cover and was more beneficial for in-stream biodiversity, whereas restoration with wood tended to increase hydrological retention of stream channels, thereby altering riparian plant assemblages toward more natural composition. In a mesocosm experiment, I found mosses to have a strong impact on macroinvertebrate communities and ecosystem functions. Mosses increased organic matter retention and reduced algal accrual rate and leaf decomposition. The effect of mosses on macroinvertebrates was stronger than that of sand sedimentation, and mosses mitigated some of the negative effects of sand. Extensive dispersal had a distinct imprint on invertebrate community composition but did not blur the effect of mosses and sand on communities, suggesting strong local-scale environmental control of composition. My thesis emphasizes that priority in stream restoration should be in the mitigation of diffuse pollution rather than restoration of channel morphology, especially in streams where channel alteration has been fairly modest, as in the case of timber floating. Addition of both boulders and large wood likely yields the best biodiversity response in the restoration of forestry impacted streams. Mosses are a key component of boreal lotic ecosystems; therefore, the recovery of mosses may be a prerequisite for the full recovery of biodiversity and ecosystem integrity of boreal streams
Tiivistelmä Ihmisen toiminta on laajasti muokannut virtavesiä. Uomien kanavointi ja maankäyttö ovat muuttaneet virtavesien elinympäristöjä ja veden laatua, millä on ollut haitallisia vaikutuksia virtavesien luonnon monimuotoisuuteen ja ekosysteemin toimintaan. Huonokuntoisia virtavesiä on kunnostettu paljon, mutta ymmärrys siitä, kuinka virtavesiä tulisi kunnostaa parhaan ekologisen lopputuloksen saavuttamiseksi, on edelleen vajaata. Tutkin tässä väitöskirjassa uittoperkausten ja maatalouden hajakuormituksen merkitystä ja yhteisvaikutusta virtavesien eliöyhteisöihin. Tutkin myös kunnostusten vaikutusta hiekasta kärsivissä metsätalouden muokkaamissa puroissa, sekä vesisammalten, hiekan ja eliöiden levittäytymisen merkitystä purojen pohjaeläinyhteisöjen ja ekosysteemin toimintojen muovautumisessa. Havaitsin, että uoman perkauksilla ei ollut vaikutusta virtavesien eliöyhteisöihin, mutta hajakuormituksen vaikutus oli voimakas. Perkauksella ja hajakuormituksella ei ollut yhteisvaikutuksia eliöyhteisöihin. Osoitin, että metsäojituksista aiheutuva ylimääräinen hiekan sedimentaatio on haitallista virtavesien eliöille, mutta sillä ei ollut vaikutusta lehtikarikkeen hajotukseen tai päällyslevien tuotantoon. Kunnostukset joissa käytettiin kiveä vähensivät hiekan peittävyyttä ja olivat hyödyllisempiä uoman eliöstölle kuin kunnostukset, joissa tehtiin puurakennelmia. Puukunnostukset kuitenkin lisäsivät uoman vedenpidätyskykyä ja siten muokkasivat rantavyöhykkeen kasvillisuutta luonnontilaisemmaksi. Havaitsin, että vesisammalilla on voimakas vaikutus pohjaeläinyhteisöjen koostumukseen. Sammalet vaikuttivat ekosysteemin toimintoihin lisäämällä eloperäisen aineksen pidättymistä ja vähentämällä lehtikarikkeen hajotusta ja päällyslevien tuotantoa. Sammalten vaikutus pohjaeläimiin oli voimakkaampi kuin hiekan, ja sammalet kykenivät jopa lieventämään joitakin hiekan negatiivisia vaikutuksia. Eliöiden levittäytymisellä oli selvä vaikutus yhteisöjen koostumukseen, mutta se ei hävittänyt hiekan ja sammalen vaikutusta, mikä viittaa korkeaan ympäristötekijöiden merkitykseen yhteisöjen rakentumisessa. Tutkielmani korostaa, että maatalousjokien tilan parantamisessa hajakuormituksen hallinta tulisi olla ensisijainen kunnostustavoite uoman rakenteen kunnostamisen sijaan. Metsätalouden vaikutuksista kärsivissä puroissa kivi- ja puumateriaalin käyttö samanaikaisesti tuottaa luultavimmin laajimman vaikutuksen purojen monimuotoisuuteen. Sammalilla on merkittävä vaikutus muiden eliöiden yhteisökoostumukseen ja ekosysteemin toimintoihin, joten sammalten palautuminen on tärkeä kunnostustavoite virtavesissä, joissa on luonnostaan paljon sammalkasvustoa

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Ferro, Yannis. "Évaluation de l'impact des rejets urbains de temps de pluie sur le compartiment algal des écosystèmes aquatiques : Mise au point d'outils pour la surveillance des milieux récepteurs." Phd thesis, INSA de Lyon, 2013. http://tel.archives-ouvertes.fr/tel-00994535.

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La gestion des eaux pluviales constitue un défi important à relever dans les villes du monde entier : aujourd'hui on ne compte plus les problèmes d'inondation et de pollution, problèmes chroniques qui tendent à s'amplifier à mesure que l'urbanisation grandit en parallèle du changement climatique. Une gestion durable de ces eaux est au cœur des enjeux du XXIe siècle et afin de faire face à ces problèmes le Ministère de l'Écologie et du Développement Durable a engagé une opération de recherche sur cette thématique. Parmi les problèmes posés par les eaux pluviales, notre étude se focalise sur les rejets urbains de temps de pluie (RUTP). Ces rejets constituent un apport important et imprévisible de nombreux polluants pour les masses d'eaux réceptrices. La pollution des RUTP est étudiée depuis de nombreuses années et, alors que les connaissances en la matière s'affinent, il n'existe à l'heure actuelle aucune étude de grande ampleur permettant d'identifier l'impact des RUTP sur les écosystèmes récepteurs. Notre travail a consisté à étudier l'impact environnemental de différents échantillons de RUTP collectés sur 3 sites d'assainissement pluvial de l'agglomération lyonnaise. Pour cela nous avons sélectionné des bioindicateurs pertinents, les microalgues d'eau douce, organismes unicellulaires à la base des chaînes trophiques et très sensibles aux polluants présents dans les RUTP. Nous avons réalisé des bioessais écotoxicologiques connus de la littérature et contribué au développement de nouveaux indicateurs de toxicité complémentaires. De plus nous avons cherché à adapter ces bioessais pour permettre leur utilisation sur le terrain. En parallèle nous avons travaillé à l'amélioration d'un biocapteur enzymatique à cellules algales. Ses performances ont été évaluées sur des échantillons de RUTP avant d'œuvrer à la construction d'une station automatisée qui nous a permis de réaliser des mesures directement sur les sites d'assainissement (on line monitoring). Ce travail contribue à mettre en évidence l'impact important des RUTP sur le milieu récepteur tout en confirmant le caractère hétérogène de ce type d'effluent et l'intérêt des dispositifs de surveillance in situ.

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Alestra, Tommaso. "Impacts of altered physical and biotic conditions in rocky intertidal systems: implications for the structure and functioning of complex macroalgal assemblages." Thesis, University of Canterbury. School of Biological Sciences, 2014. http://hdl.handle.net/10092/10025.

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Complex biogenic habitats created by large canopy-forming macroalgae on intertidal and shallow subtidal rocky reefs worldwide are increasingly affected by degraded environmental conditions at local scales and global climate-driven changes. A better understanding of the mechanisms underlying the impacts of complex suites of anthropogenic stressors on algal forests is essential for the conservation and restoration of these habitats and of their ecological, economic and social values. This thesis tests physical and biological mechanisms underlying the impacts of different forms of natural and human-related disturbance on macroalgal assemblages dominated by fucoid canopies along the east coast of the South Island of New Zealand. A field removal experiment was initially set up to test assemblage responses to mechanical perturbations of increasing severity, simulating the impacts of disturbance agents affecting intertidal habitats such as storms and human trampling. Different combinations of assemblage components (i.e., canopy, mid-canopy and basal layer) were selectively removed, from the thinning of the canopy to the destruction of the entire assemblage. The recovery of the canopy-forming fucoids Hormosira banksii and Cystophora torulosa was affected by the intensity of the disturbance. For both species, even a 50% thinning had impacts lasting at least eighteen months, and recovery trajectories were longer following more intense perturbations. Independently of assemblage diversity and composition at different sites and shore heights, the recovery of the canopy relied entirely on the increase in abundance of these dominant fucoids in response to disturbance, indicating that functional redundancy is limited in this system. Minor understory fucoids, which could have provided functional replacement for the dominant habitat formers, had reduced rates of growth or recruitment when the overlying canopy was disturbed. I then used a combination of field and laboratory experiments to test the impacts of physical and biotic stress sources on the dominant fucoids H. banksii and C. torulosa. The large fucoid Durvillaea antarctica was also included in one of the laboratory investigations. I assessed how altered physical and biotic conditions affect these important habitat formers, both separately and in combination. Physical stressors included increased sedimentation, nutrient enrichment and warmer water temperatures. Biotic stress originated from interspecific competition with turfs of articulated coralline algae and ephemeral, fast-growing green and brown algae. Sediment deposition severely reduced the survival and growth of recently settled H. banksii, C. torulosa and D. antarctica germlings in laboratory experiments. In the field, the recruitment of H. banksii on unoccupied substrates was significantly higher than in treatments in which sediments or mats of turf-forming coralline algae covered the substrate. This shows that sediment deposition and space pre-emption by algal turfs can synergistically affect the development of fucoid beds. Further impacts of sediment accumulation in the benthic environment were investigated using in situ and laboratory photorespirometry techniques to assess the contribution of coralline algae to assemblage net primary productivity (NPP), both in the presence and absence of sediment. The NPP of articulated corallines was reduced by sediment. Sediment accumulation among the thalli limited the access of the corallines to the light and induced photoinhibitive mechanisms. In the absence of sediment, however, coralline algae enhanced the NPP of assemblages with a fucoid canopy, showing the importance of synergistic interactions among the components of multi-layered assemblages in optimizing light use. Nutrient enrichment had a less pervasive influence on the dominant fucoids H. banksii and C. torulosa than sedimentation. In laboratory experiments, nutrients stimulated the growth of H. banksii and C. torulosa germlings. However, negative impacts of high nutrient levels were observed for the early life stages of D. antarctica. The abundance of opportunistic, fast-growing algae rapidly increased in response to nutrient enrichment both in the laboratory and in the field. Impacts of ephemeral species on fucoid early life stages were only evident in laboratory contexts, where green algae of the genus Ulva impaired both the settlement of H. banksii zygotes and the growth of its germlings. Fucoid recruitment in the field was not affected by increased covers of ephemeral algae caused by enhanced nutrient regimes, indicating that H. banksii and C. torulosa may be resistant to short-term (one year) nutrient pollution. In the laboratory, increased temperatures within the range predicted for the end of the 21st century caused increased mortality in the H. banksii, C. torulosa and D. antarctica germlings. In a separate experiment, a combination of warmer water temperatures and nutrient enrichment enhanced the growth of ephemeral green algae. These results suggest that opposite responses to altered climate conditions may contribute to shifts from complex biogenic habitats dominated by macroalgal canopies to simplified systems monopolized by a limited number of stress-tolerant species. This research contributes to a clearer mechanistic understanding of biotic and physical mechanisms shaping the structure of coastal marine hard bottom communities under increasingly stressful conditions worldwide. These findings may provide insights for other studies investigating the complex mosaic of challenges facing marine coastal ecosystems.

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Ramos, Geraldo Jos? Peixoto. "Algas verdes coc?ides (Chlorophyta) de duas ?reas do Pantanal dos Marimbus (Baiano e Remanso), APA Marimbus-Iraquara, Chapada Diamantina, Bahia, Brasil." Universidade Estadual de Feira de Santana, 2013. http://localhost:8080/tede/handle/tede/260.

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Submitted by Natalie Mendes (nataliermendes@gmail.com) on 2015-11-12T23:29:45Z No. of bitstreams: 1 Ramos 2013 - Algas verdes cocoides (Chlorophyta) de duas ?reas do pantanal dos Marimbus (Baiano e.pdf: 8915844 bytes, checksum: 4608fb4b95cdad6269d11095980552c4 (MD5)
Made available in DSpace on 2015-11-12T23:29:45Z (GMT). No. of bitstreams: 1 Ramos 2013 - Algas verdes cocoides (Chlorophyta) de duas ?reas do pantanal dos Marimbus (Baiano e.pdf: 8915844 bytes, checksum: 4608fb4b95cdad6269d11095980552c4 (MD5) Previous issue date: 2013-03-14
Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES
This study aimed at surveying the coccoid green algae flora of two areas of the Pantanal dos Marimbus (Baiano and Remanso), EPA Marimbus Iraquara, located in the Chapada Diamantina, Bahia, Brazil. Material was obtained from 120 samples collected during the dry (April, June and August 2011) and in the rainy season (October and December 2011, and February 2012). During this study 121 taxa of coccoid green algae were identified, described, illustrated and commented, which are distributed in two classes, four orders and 46 genera, 109 species, three varieties typical and seven other does not typical of their respective species, and two taxonomic formae. 17 (14%) of the total of taxa identified are pioneer citations for Brazil, 51 taxa (42%) for the Northeast Region of Brazil, and 19 taxa (15,7%) for the Bahia State. Most taxa recorded were classified in the Sphaeropleales (76%), followed by Chlorellales (17%), Trebouxiales (3%) and Chlorococcales ?sensu stricto? (2%), while the taxa considered ?incertaesedis? were represented by 3% of the total taxa identified. Among the taxa studied in both areas, 14 were exclusive of the rainy period and only seven of the dry one, while 100 taxa were common to both climatic periods. The species richness was clearly higher in the Marimbus do Baiano with 115 taxa (95%), while the Marimbus do Remanso showed 99 taxa (82.5%). Of the 121 taxa studied, 22 were unique to the Marimbus do Baiano and six to the Marimbus do Remanso. According to the S?rensen similarity index (86.9%), the similarity between the Marimbus do Baiano and do Remanso was considered high. Most taxa inventoried (48%) was classified as rare on Pantanal Marimbus, followed by infrequent (42%), frequent (7%) and very frequent (3%). Considering that about 90% of the taxa found are listed first for the Bahia State, we strongly suggest continuing studies of biodiversity of inland water algae to increase knowledge of phycoflora in Bahia State and Brazil.
O presente estudo ? o levantamento flor?stico das algas verdes coc?ides ocorrentes em duas ?reas do Pantanal dos Marimbus (Baiano e Remanso), APA Marimbus Iraquara, localizada na Chapada Diamantina, Bahia, Brasil. Os materiais estudados provieram de 120 amostras coletadas no per?odo seco (abril, junho e agosto de 2011) e no chuvoso (outubro e dezembro de 2011 e fevereiro de 2012). Foram identificados, descritos, ilustrados e comentados 121 t?xons de algas verdes coc?ides, distribu?dos em duas classes, quatro ordens e 46 g?neros, 109 esp?cies, tr?s variedades t?picas e sete n?o t?picas de suas respectivas esp?cies e duas formas taxon?micas. Do total de t?xons inventariados, 17 t?xons (14%) s?o cita??es pioneiras para o Brasil, 51 t?xons (42%) para a Regi?o Nordeste do Brasil e 19 t?xons (15,7%) para o Estado da Bahia. A maior riqueza de t?xons foi registrada para a ordem Sphaeropleales (76%), seguida de Chlorellales (17%), Trebouxiales (3%) e Chlorococcales ?sensu strictu? (2%), enquanto que os t?xons considerados ?incertae sedis? foram representados por 3% do total. Dentre os t?xons estudados nas duas ?reas, 14 foram exclusivos do per?odo de chuva e apenas sete do per?odo de seca, enquanto que 100 t?xons foram comuns a ambos os per?odos clim?ticos. A riqueza espec?fica foi claramente maior no Marimbus do Baiano, com 115 t?xons (95%), enquanto que o Marimbus do Remanso apresentou 99 t?xons (82,5%). Dos 121 t?xons inventariados, 22 t?xons foram exclusivos do Marimbus do Baiano e seis do Marimbus do Remanso. De acordo com o ?ndice de Similaridade de S?rensen (86,9%), a similaridade entre os Marimbus do Baiano e do Remanso foi elevada. A maior parte dos t?xons inventariados (48%) foi classificada como de ocorr?ncia rara no Pantanal dos Marimbus, seguido de pouco frequente (42%), frequente (7%) e muito frequente (3%). Considerando que cerca de 90% dos t?xons encontrados s?o referidos pela primeira vez para o Estado da Bahia, sugere-se a continuidade dos estudos de biodiversidade de algas de ?guas continentais para ampliar o conhecimento da ficofl?rula na Bahia e no Brasil.

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Moulin, Solène. "Synthesis of hydrocarbons in algae : from biodiversity to biotechnology." Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0429.

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Les hydrocarbures (HCs) sont prédominants dans notre économie actuelle (carburants, cosmétiques, chimie, etc.) mais sont quasi-exclusivement issus des ressources fossiles. Les problématiques de changement climatique et d’épuisement des ressources poussent les recherches vers l’étude et la domestication des voies de synthèse naturelles d’HCs. Lorsque j’ai commencé ma thèse, une enzyme de biosynthèse d’HC, l’acide gras photodécarboxylase (FAP) venait d’être découverte chez la microalgue Chlorella. J’ai d’abord caractérisé son homologue chez la microalgue modèle Chlamydomonas. Une étude phylogénétique de la famille des GMC oxidoréductases à laquelle appartient la FAP a permis d’identifier un large réservoir de de 200 FAPs putatives. La caractérisation biochimique de plusieurs d’entre elles a permis de montrer qu’une FAP fonctionnelle a été conservée lors des endosymbioses secondaires. Cela suggère que la FAP joue un rôle important chez les algues. Ce rôle a été étudié par une approche de génétique inverse chez Chlamydomonas. La caractérisation physiologique de mutants knockout a permis de démontrer le rôle de la FAP dans la synthèse d’HCs dans le chloroplaste et de mettre en évidence des modifications physiologiques transitoires. Des mécanismes de compensation à l’absence d’HCs restent donc à découvrir. Dans une dernière partie, j’ai développé une souche d’E. coli exprimant la FAP et une thioestérase. Cette souche produit en continu des HCs dans la phase gaz des cultures, ce qui permet une récolte facilitée du produit d’intérêt sous forme pure. Cette étude constitue une preuve de concept que la FAP pourrait être utilisée pour la production biosourcée d’HCs
Hydrocarbons (HCs) are predominant in our current economy (fuels, cosmetics, chemicals, etc.) but are almost exclusively derived from fossil resources. Climate change and resource depletion concerns are pushing research towards the study and domestication of natural HC synthesis pathways. When I started my thesis, a HC forming enzyme, the fatty acid photodecarboxylase (FAP) had just been discovered in the microalgae Chlorella. I first characterised its homolog in the model microalgae Chlamydomonas. A phylogenetic study of the GMC oxidoreductase family to which the FAP belongs has allowed identification of a large reservoir of 200 putative FAPs. Biochemical characterisation of several of them showed that a functional FAP was maintained during secondary endosymbiosis. This suggests that FAP plays an important role in algae. This role has been studied by a reverse genetic approach in Chlamydomonas. The physiological characterisation of knockout mutants demonstrated the role of FAP in the synthesis of HCs in chloroplasts as well as transient physiological changes. Mechanisms to compensate for the absence of HCs therefore remain to be discovered. In a last part, I developed a strain of E. coli expressing the FAP and a thioesterase. This strain continuously produces HCs in the gas phase of the cultures, which allows an easier harvesting of the product of interest in a pure form. This study is a proof of concept that FAP could be used for the biobased production of HCs

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Mystikou, Alexandra. "Seaweed biodiversity around the Antarctic Convergence in the South Atlantic." Thesis, University of Aberdeen, 2015. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=227597.

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This study focuses on the seaweed biodiversity around the Antarctic Convergence in the South Atlantic. It integrates field work in the Falkland Islands and surrounding regions with algal culturing, molecular techniques, microscopy and morphological identification. Chapter 2 explores the diversity of seaweeds of the south-western Antarctic Peninsula which is poorly studied, contrasting with the substantial knowledge available for the northern parts of the Peninsula. A baseline seaweed species checklist for the southern Adelaide Island and northern Marguerite Bay region is presented here, combining data obtained during a small number of surveys in 1973-5 and a six week intensive diving-based field campaign in 2010-2011. Subantarctic and Antarctic regions remain little studied in their seaweed diversity. Chapter 3 is based upon field collections in the early 1970s and 2007-2013. It is supported by sequencing COI and reports new records of several macroalgal species and an oomycete. Chapter 4 revisits the enigmatic Subantarctic brown alga Cladochroa chnoosporiformis, which had been collected only on one occasion by Carl Skottsberg in 1907 from Port Philomel, West Falkland, resulting in its formal taxonomic description. Within the framework of this study, Cladochroa was rediscovered after 106 years at its type locality, confirming its existence and morphological features as described by Skottsberg. The recollection enabled molecular studies of its phylogenetic placement by DNA sequencing, suggesting that C. chnoosporiformis is conspecific with Utriculidium durvillei. In Chapter 5, DNA barcoding was applied to both seaweed tissue samples taken while preparing herbarium specimens during 2 expeditions to the Falkland Islands, and to live macroalgal isolates obtained from substratum samples using the Germling Emergence Method. In several cases, this enabled detection of previously unsequenced or undescribed taxa, respectively. The potential and challenges of applying DNA barcoding for cataloguing the biodiversity of remote bioregions such as the Falklands are discussed.

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Martín, Martín Rafael Pablo. "Benthic marine algae from South Shetland Islands (Antarctica): biodiversity and evolutionary patterns." Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/673828.

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The present work focuses on different aspects related to the Antarctic seaweed. As the main primary producers of the coastal areas of Antarctica, this group of organisms play a key role in shaping the biological communities and the ecological dynamics of Antarctic shores. However, compared to other groups of Antarctic organisms or the seaweed communities of other regions of the world, Antarctic macroalgae remain less studied. This is especially true in several areas of knowledge as their actual biodiversity, their evolutionary history and patterns, some aspects of their ecology or the total extent of their relations with other Antarctic organisms and their environment. Aiming to address the lack of knowledge of these areas, we aimed to extend it by focusing our work in several key aspects of Antarctic seaweed biology. As so, we tried to respond several specific questions regarding the topics above mentioned. In this context, we studied biodiversity of seaweed communities that are present in the South Shetland Islands. For that, we tried to identify the composition and influencing factors of the seaweed assemblages present in Deception Island. We also studied how seaweed biodiversity affects Antarctic epiphytic diatoms richness, studying the composition of them, both from Deception and Livingston islands. Moreover, we tried to expand the data with evolutionary relevance by analysing the nuclear DNA content and ploidy levels (C values), as well as the nuclear developmental patterning of some common Antarctic seaweed species with no previous data for those characters. This was achieved by using a fluorimetry technique that sets a reference for comparison for future studies on those parameters. Additionally, we condensed the latest knowledge on the chemical ecology of seaweeds and other organisms from Antarctica, and tried to expand it by investigating the potential antimicrobial activity of these seaweeds. For this, we tested their natural extracts against several Antarctic microorganisms and identified several species that were active chemically. Also, we tested the same extracts for antimicrobial action against several microorganisms that are common human pathogenic surrogates and identified potential human interest in these seaweeds on the search for new sources of antibiotics. Finally, we reported our findings on the role seaweed have in the context of climate change in the Antarctic region. Those findings include the identification of non-native kelp rafts that arrived to the maritime Antarctica, and presented several passenger species that have potential invasiveness in the Antarctic. Regarding that, we classified and explored the possible roles that the rafts themselves and the species travelling with them may play in futures scenarios of climate change in Antarctica.

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Raccagni, Monica. "Organic nitrogen uptake by marine algae : consequences for marine ecosystem functioning and biodiversity." Thesis, University of Plymouth, 2018. http://hdl.handle.net/10026.1/12816.

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Dissolved organic nitrogen (DON) represents a major pool of fixed, reactive nitrogen in marine systems. It is now recognized that this pool can support primary production and the ability of some algal species to exploit DON compounds as sources of Nitrogen (N) may indicate that specific DON components can exert selective pressure on the composition of the phytoplankton community. In this study the ability of monocultures of ecologically-relevant algal species from the English Channel (Emiliania huxleyi, Micromonas pusilla, Alexandrium minutum and Chaetoceros peruvianus) to grow with DON as the only N source was examined using different artificial media. Among the two tested artificial seawater recipes, Aquil* was preferred as it contained lower micronutrient concentrations, and gave better growth results for all used species. In order to constrain the DON uptake to algae alone, a method for bacterial removal was tested using antibiotic additions. Both Slocombe antibiotic mixture (Cefotaxime-Carbenicillin-Kanamycin-AugmentinTM) and Penicillin-Streptomycin-Neomycin used were effective and not toxic to the algae. Incubation with the antibiotic up to 48 hours and a transfer period into antibiotic-free medium after 72 hours proved to be effective. However, the treatment removed bacteria in A. minutum cultures only; further treatment would be required for the other species to be cultured axenically. The ability to use DON was tested for the above mentioned species using the amino acid L-Arginine (ARG) as the sole N source, and growth was compared with nitrate-containing cultures of the same species. All the selected species grew in both NOᴈ‾ and in ARG, reaching lower final densities when incubated with ARG, although these were not significant. This study has shown that E. huxleyi, A. minutum, M. pusilla and C. peruvianus can grow on organic N, either by direct or indirect uptake, and develop comparable biomasses to species using inorganic N. Both C. peruvianus and M. pusilla cultures contained dissolved ammonium at the end of the experimental period, indicating potential indirect use by the algae of organic N converted to inorganic N by bacteria. A. minutum grew in the presence of ARG along with the cosmopolitan E. huxleyi; N-demand estimates, based on the molar concentration of N-ARG consumed, correlated with the final cell density, indicating that the species did not develop on inorganic N produced from ARG mineralisation, but directly on the ON substrate. Since A. minimum has been linked to harmful algal blooms, and E. huxleyi contributes significantly to oceanic CaCOᴈ deposition, their ability to utilise DON has environmental consequences in addition to the oceanic N-budget. Climate change scenarios predict both episodic conditions of elevated rainfall and extended periods of dry conditions leading to variable riverine inputs to coastal areas, altered nitrogen to phosphorus (N:P) ratios, and changes in the inorganic to organic balance of the nutrient pools. Organic N can constitute up to 69 % of the total N pools, respectively, making it crucial, to understand the cycling of this fraction in coastal waters, and how changes in the composition of nutrient pools could impact on marine ecosystem function and health.

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Daniels, Fahiema. "The effects of catchment management and salinity on the dominant macro-algae in the Bot River estuary." Thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/26647.

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Marazzi, L. "Biodiversity and biomass of algae in the Okavango Delta (Botswana), a subtropical flood-pulsed wetland." Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1459199/.

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In freshwater bodies algae provide key ecosystem services such as food and water purification. This is the first systematic assessment of biodiversity, biomass and distribution patterns of these aquatic primary producers in the Okavango Delta (Botswana), a subtropical flood-pulsed wetland in semiarid Southern Africa. This study delivers the first estimate of algal species and genera richness at the Delta scale; 496 species and 173 genera were observed in 132 samples. A new variety of desmid (Chlorophyta) was discovered, Cosmarium pseudosulcatum var. okavangicum, and species richness estimators suggest that a further few hundred unidentified species likely live in this wetland. Rare species represent 81% of species richness and 30% of total algal biovolume. Species composition is most similar within habitat types, thus varying more significantly at the Delta scale. In seasonally inundated floodplains, algal species / genera richness and diversity are significantly higher than in permanently flooded open water habitats. The annual flood pulse has historically allowed more diverse algal communities to develop and persist in these shallower and warmer environments with higher mean nutrient levels and more substrata and more heterogenous habitats for benthic taxa. These results support the Intermediate Disturbance Hypothesis, Species-Energy Theory and Habitat Heterogeneity Diversity hypotheses. Higher algal biodiversity supports higher algal biomass in the floodplains, where species form three-dimensional communities of attached and periphytic algae requiring more nutrients than phytoplankton assemblages. Multivariate analyses demonstrate that habitat type, flooding frequency and conductivity most importantly influence the relative abundance of algal species, genera and phyla in the Okavango Delta. This study’s findings highlight how the preservation of water level fluctuations and habitat heterogeneity is crucial to maintaining biodiverse and thus resilient food webs in this unique ecosystem which faces increasing anthropogenic threats, such as global warming and upstream water abstraction plans.

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Bussell, James Alexander. "Biodiversity of the invertebrate community associated with the turf-forming red alga Corallina officinalis in tide pools." Thesis, Bangor University, 2003. https://research.bangor.ac.uk/portal/en/theses/biodiversity-of-the-invertebrate-community-associated-with-the-turfforming-red-alga-corallina-officinalis-in-tide-pools(1d7050da-ef40-41c5-9587-c7151a1e12f5).html.

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The invertebrate communities associated with the turf-forming red alga Corallina officinalis were investigated in tide pools on rocky shores of the coasts of England, Ireland and Wales. A total of 212 different taxa, including representatives from 14 phyla, were identified. There was significant small scale (between pools and within pools) variability and large scale variability (regional, between shores) in the diversity and community patterns of invertebrates associated with Corallina turf. These patterns were often not consistent between different shores and at different times. For example, greater numbers of species were found amongst Corallina turf from shallow depth in tide pools in winter than in summer. At regional scales, differences in the community pattern are correlated with temperature, though overall differences appear to be driven by a complex and interacting arrangement of biotic and abiotic factors such as habitat complexity and the hydrodynamic regime of the area. These patterns are also found when working at taxonomic levels other than species. Distinct temporal variation in the community was observed that followed a seasonal cyclic template. The observed temporal pattern is produced primarily by the behavioural adaptations and life history characteristics of the associated invertebrates. Assemblages associated with the tide pools frequently contained invertebrates that are small in size, produce few juveniles and have a tendency to brood their offspring or reproduce without a pelagic larval stage. These characteristics result in a clearly distinct community associated within Corallina turf on the coasts of the UK and Ireland. Patterns of the invertebrates associated with Corallina turf make an important contribution to our understanding of marine biodiversity. By examining such patterns in similar habitats at similar scales it is possible to make decisions concerning the conservation of the inshore marine environment.

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Wolf, Daniel I. Wolf. "Multi-marker Metabarcoding Assessment of Biodiversity within Stream Biofilm Communities along an Acid Mine Drainage Recovery Gradient." Ohio University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou152594729270327.

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Loron, Corentin. "Biodiversity of Organic-Walled Eukaryotic Microfossils from the Tonian Visingsö Group, Sweden." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-297158.

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The diversification of unicellular, auto- and heterotrophic protists and the appearance of multicellular microorganisms is recorded in numerous Tonian age successions worldwide, including the Visingsö Group in southern Sweden. The Tonian Period (1000-720 Ma) was a time of changes in the marine environments with increasing oxygenation and a high input of mineral nutrients from the weathering continental margins to shallow shelves, where marine life thrived. This is well documented by the elevated level of biodiversity seen in global microfossil record. The Visingsö Group contains a taxonomically rich assemblage of cyanobacteria, stromatolites, algal phytoplankton, and vase-shaped microfossils. A new study of organic-walled, phytoplanktic microfossils, which are extracted by palynological method from the Visingsö 1 borehole samples, reveals the presence of morphologically disparate taxa. They are in gross cysts of microalgae (Pterospermopsimorpha, Pterospermella, Cerebrosphaera, Trachysphaeridium, Simia and certain Leiosphaeridia with pylome) and some are of uncertain affinities (acritarchs). Representative taxa of two lineages among green algae, Prasinophyceae and Chlorophyceae, are recognized. Cyanobacterial clusters and filaments are abundant and specimens of multicellular, yet systematically unrecognized taxa are recorded. Taxonomically, the assemblage is similar to some from other successions distributed along the margins of Baltica, Laurentia and Siberia in the Tonian Period. The ecological habitats of those organisms are inferred by comparing with their potential modern analogues and from the sedimentological setting of the upper formation of the Visingsö Group.
Denna studie handlar om biodiversiteten och den biologiska affiniteten av mikrofossil från den neoproterozoiska eran, tonianperioden (1000-720 Ma). De har extraherats från övre formationen av Visingsögruppen i södra Sverige.Mikrofossilen har organiska cellväggar, är encelliga och har förmodats representera algcystor (resistenta reproduktiva strukturer), cyanobakterier, och andra organismer av okänd tillhörighet. Neoproterozoikum har den högsta graden av biologisk diversitet under prekambrium. Det är därför viktigt att studera diversiteten för att förstå utvecklingen av biosfären under denna period i samband med utvecklingen av miljöer. Den studerade samlingen härrör från ett borrhål på Visingsö i Vättern, och visar på större diversitet än från tidigare studier.Denna nya studie syftar till att bestämma biodiversiteten i den övre formationen av Visingsögruppen och att känna igen affiniteten av mikrofossilen med organiska väggar och deras ekologi. Vissa av de undersökta mikrofossilen hör sannolikt till grönalgerna. Kluster och fiber av cyanobakterier är rikligt förekommande, och några prover är ej biologiskt igenkännbara. Med hjälp av moderna analoger och sedimentologiska data är ekologin hos dessa mikrofossil utläs

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Barros-Alves, Samara de Paiva [UNESP]. "Biodiversidade de caranguejos Branquiúros (Crustacea, Decapoda) associada a bancos da alga Sargassum cymosum (C. Agardh, 1820) na região da Ubatuba, Litoral Norte Paulista." Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/99471.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O objetivo desta investigação é descrever e comparar a comunidade de decápodos braquiúros associados a bancos da alga S. cymosum (C. Agardh, 1820), em duas praias do litoral norte paulista. Foram realizadas coletas mensais durante o período de janeiro a dezembro de 2001, na região do entre-marés no substrato rochoso em bancos de S. cymosum nas praias Grande (23º23’S–45º03’W) e Domingas Dias (23º29’S–45º08’W), em Ubatuba. Em laboratório, os caranguejos foram submetidos a identificação taxonômica, mensurados quanto a largura de carapaça (LC) e identificados quanto ao sexo e fase do desenvolvimento. Foram obtidos 1948 indivíduos, reunidos em 23 espécies. Na praia Grande foram coletados 1115 indivíduos, distribuídos em 20 espécies, pertencentes a 5 superfamílias. Para a praia Domingas Dias foram obtidos 833 indivíduos, entre os quais foram registradas 21 espécies, de 4 superfamílias. Para a praia Domingas Dias Epialtus bituberculatus foi a espécie dominante enquanto que para a praia Grande, a dominância foi compartilhada por E. bituberculatus, Menippe nodifrons. Houve diferença significativa acerca do índice de diversidade (Mann-Whitney; p=0,0130) entre as praias, sendo que a praia Grande apresentou o maior valor para o índice (1,86nats/ind.). Essa diferença observada para a diversidade entre as praias Grande e Domingas Dias, pode refletir o fato de que ambientes mais heterogêneos geralmente abrigam maiores diversidades, sendo a praia Grande considerada como um ambiente mais heterogêneo e sujeita a maior exposição aos distúrbios ambientais, como ação de ondas, apresentando dominância compartilhada entre duas espécies enquanto a praia Domingas Dias, mais estável, apresentou expressiva dominância de uma única espécie, o que promoveu um baixo valor para o índice de diversidade. Desse modo, a maior ou menor exposição às ondas...
The objective of this research was to describe and compare the communities of brachyuran decapods associated with banks of the seaweed Sargassum cymosum (C. Agardh, 1820), on two beaches of the northeastern coast of São Paulo State. Monthly collections were conducted from January to December 2001, in seaweed banks on the intertidal rocky bottoms of the Grande (23º23'S-45°03'W) and Domingas Dias beaches (23º29'S-45º08'W). In the laboratory, the crabs were identified to species level and measured for carapace width (CW), sexed, and their developmental stage identified. A total of 1948 individuals were obtained, representing 23 species. On Grande Beach, 1115 individuals were captured, of 20 species in 5 superfamilies. On Domingas Dias Beach, 833 individuals were obtained, of 21 species in 4 superfamilies. On Domingas Dias Beach, Epialtus bituberculatus was the dominant species, whereas on Grande Beach, dominance was shared between E. bituberculatus and Menippe nodifrons. The diversity index differed significantly (Mann-Whitney, p=0.0130) between the beaches, being higher at Grande (1.86 bits/ind.). This difference in diversity is due to the fact that more heterogeneous environments generally show a greater diversity. Two co-dominant species occurred at Grande Beach, which is a more heterogeneous environment, exposed to environmental disturbances such as wave motion. A significant dominance of only one species was recorded at the more stable Domingas Dias Beach, which showed a low diversity index. In this investigation, wave motion appeared to have a strong influence on the species selection process on the rocky shore... (Complete abstract click electronic access below)

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Rodrigues, Luciana Luna Ruiz. "Biodiversidade de cianobactérias e algas das represas Billings (Braço Taquacetuba) e Guarapiranga, SP, Brasil." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/41/41132/tde-02122008-112617/.

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A biodiversidade de cianobactérias e algas fitoplanctônicas foi estudada em duas das maiores represas da Região Metropolitana de São Paulo (RMSP): Billings e Guarapiranga, que fornecem água para o abastecimento de milhões de pessoas. As amostras foram coletadas bimensalmente, em pontos próximos à captação da Sabesp, durante o período de janeiro/2004 a dezembro/2004. As amostras foram filtradas com rede de plâncton de 20m de abertura de malha, preservadas em formol e depositadas no Herbário do Instituto de Botânica (SP). Foram identificados, descritos e ilustrados, 84 táxons para as represas Billings (Braço Taquacetuba) e Guarapiranga, sendo: 36 de Chlorophyceae (43%); 17 de Cyanobacteria (20%); 13 de Euglenophyceae (15,5%); 7 de Bacillariophyceae (8,5%); 5 de Zygnematophyceae (6%); 3 de Xantophyceae (3,5%); 2 de Dinophyceae (2,5%) e 1 de Chrysophyceae (1%). Vinte e três táxons foram considerados como primeiras referências para as represas estudadas. Nove espécies de cianobactérias potencialmente tóxicas foram identificadas para as duas represas. O resultado do índice de similaridade de Sörensen apontou alta similaridade entre as floras fitoplanctônicas de ambas as represas.
Biodiversity of planktonic cyanobacteria and algae in two of the greatest reservoirs from the Metropolitan Region of São Paulo (RMSP), Billings and Guarapiranga, which supply water for millions of people was studied. The samples were collected every two months, in a specific site (Sabesps water sourcing) in both reservoirs, from January to December 2004. The samples were filtered using a plankton net (20m) and were preserved with formaldehyde. The studied samples were kept in the Herbarium of the Institute of Botany (SP). Eighty-four taxa were identified, described and illustrated: thirty-six belong to Chlorophyceae (43%); seventeen to Cyanobacteria (20%); thirteen to Euglenophyceae (15.5%); seven to Bacillariophyceae (8.5%); five to Zygnematophyceae (6%); three to Xantophyceae (3.5%); two to Dinophyceae (2.5%) and one to Chrysophyceae (1%). Twenty three taxa were considered as new references to the studied reservoirs and nine potentially toxic species of cyanobacteria were identified. The Sorensen index showed high similarity between the phytoplanktonic floras of both reservoirs.

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Barros-Alves, Samara de Paiva. "Biodiversidade de caranguejos Branquiúros (Crustacea, Decapoda) associada a bancos da alga Sargassum cymosum (C. Agardh, 1820) na região da Ubatuba, Litoral Norte Paulista /." Botucatu : [s.n.], 2009. http://hdl.handle.net/11449/99471.

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Orientador: Valter José Cobo
Banca: Marcos Domingos Siqueira Tavares
Banca: Rogério Caetano da Costa
Resumo: O objetivo desta investigação é descrever e comparar a comunidade de decápodos braquiúros associados a bancos da alga S. cymosum (C. Agardh, 1820), em duas praias do litoral norte paulista. Foram realizadas coletas mensais durante o período de janeiro a dezembro de 2001, na região do entre-marés no substrato rochoso em bancos de S. cymosum nas praias Grande (23º23'S-45º03'W) e Domingas Dias (23º29'S-45º08'W), em Ubatuba. Em laboratório, os caranguejos foram submetidos a identificação taxonômica, mensurados quanto a largura de carapaça (LC) e identificados quanto ao sexo e fase do desenvolvimento. Foram obtidos 1948 indivíduos, reunidos em 23 espécies. Na praia Grande foram coletados 1115 indivíduos, distribuídos em 20 espécies, pertencentes a 5 superfamílias. Para a praia Domingas Dias foram obtidos 833 indivíduos, entre os quais foram registradas 21 espécies, de 4 superfamílias. Para a praia Domingas Dias Epialtus bituberculatus foi a espécie dominante enquanto que para a praia Grande, a dominância foi compartilhada por E. bituberculatus, Menippe nodifrons. Houve diferença significativa acerca do índice de diversidade (Mann-Whitney; p=0,0130) entre as praias, sendo que a praia Grande apresentou o maior valor para o índice (1,86nats/ind.). Essa diferença observada para a diversidade entre as praias Grande e Domingas Dias, pode refletir o fato de que ambientes mais heterogêneos geralmente abrigam maiores diversidades, sendo a praia Grande considerada como um ambiente mais heterogêneo e sujeita a maior exposição aos distúrbios ambientais, como ação de ondas, apresentando dominância compartilhada entre duas espécies enquanto a praia Domingas Dias, mais estável, apresentou expressiva dominância de uma única espécie, o que promoveu um baixo valor para o índice de diversidade. Desse modo, a maior ou menor exposição às ondas... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The objective of this research was to describe and compare the communities of brachyuran decapods associated with banks of the seaweed Sargassum cymosum (C. Agardh, 1820), on two beaches of the northeastern coast of São Paulo State. Monthly collections were conducted from January to December 2001, in seaweed banks on the intertidal rocky bottoms of the Grande (23º23'S-45°03'W) and Domingas Dias beaches (23º29'S-45º08'W). In the laboratory, the crabs were identified to species level and measured for carapace width (CW), sexed, and their developmental stage identified. A total of 1948 individuals were obtained, representing 23 species. On Grande Beach, 1115 individuals were captured, of 20 species in 5 superfamilies. On Domingas Dias Beach, 833 individuals were obtained, of 21 species in 4 superfamilies. On Domingas Dias Beach, Epialtus bituberculatus was the dominant species, whereas on Grande Beach, dominance was shared between E. bituberculatus and Menippe nodifrons. The diversity index differed significantly (Mann-Whitney, p=0.0130) between the beaches, being higher at Grande (1.86 bits/ind.). This difference in diversity is due to the fact that more heterogeneous environments generally show a greater diversity. Two co-dominant species occurred at Grande Beach, which is a more heterogeneous environment, exposed to environmental disturbances such as wave motion. A significant dominance of only one species was recorded at the more stable Domingas Dias Beach, which showed a low diversity index. In this investigation, wave motion appeared to have a strong influence on the species selection process on the rocky shore... (Complete abstract click electronic access below)
Mestre

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Branco, Magno Botelho Castelo. "Comunidade de aves aquáticas e suas interações em sistemas límnicos do sudeste brasileiro." Universidade Federal de São Carlos, 2008. https://repositorio.ufscar.br/handle/ufscar/1631.

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Financiadora de Estudos e Projetos
Aquatic birds do interact in many ways with freshwater ecosystems. Birds can be considered the most important dispersers of freshwater algae between water bodies. Moreover, birds also can contribute to nutrient loading in freshwater lakes and reservoirs. In this paper the ecto and endozoochoric dispersal potential of freshwater algae by waterbirds was acessed. The places of study were the Monjolinho reservoir, in São Carlos municipality (SP), and Tropeiros lake, in Piumhi municipality (MG). Also studied was the contribution to nutrient loading by two colonies of Bubulcus ibis, the cattle egret, in two freshwater bodies: Tropeiros lake and Iembó reservoir, locate at Parque Itaipu, São Carlos municipality. By means of culture inoculation with material obtained from washing the body of the birds, it was observed that these species of birds are potential dispersers of phytoplanktonic algae and can carry up to 22 species of algae attached to feathers per individual (ectozoochory). A minor number of species of algae was also observed in cultures inoculated with material derived from faeces of birds, featuring a potential case of endozoochoric transport potential. Regarding the nutrient loading by colony of cattle egrets, was detected a change both in the content of organic matter in the sediment located in areas where the birds sleep as well as greater eutrophication of water in these regions. It was also observed a trend to higher density of biomass in banks of aquatic macrophytes used for night rest, with a consequent increase in the density of organisms associated with aquatic macrophytes. However, no significant differences were observed in the benthic fauna, when comparing the samples of sediment obtained in both points located in the rest areas as in nonrest areas, but it was found that these colonies contribute significantly to the nutrient loading in these systems.
As aves aquáticas interagem de diversas maneiras com os ambientes de água doce. Por um lado, as aves podem ser consideradas como os mais importantes dispersores de algas fitoplancônicas entre os corpos de água doce e, por outro lado, podem contribuir de maneira significativa ao aporte de nutrientes nos ecossitemas aquáticoss. Nesse trabalho foi estudado o potencial de dispersão ecto e endozoocórico de algas fitoplanctônicas por aves aquáticas no reservatório do Monjolinho (município de São Carlos, SP) e na lagoa dos Tropeiros (município de Piumhi, MG), bem como a contribuição de colônias de garças-vaqueira Bubulcus ibis para o aporte alóctone de nutrientes em dois sistemas límnicos: a lagoa dos Tropeiros e o reservatório Iembó, localizado no condomínio Parque Itaipu, no município de São Carlos, SP. Através da inoculação de meios de cultura com material oriundo da lavagem do corpo das aves, foi observado que estas espécies de aves são potenciais dispersoras de algas fitoplanctônicas, podendo transportar até 22 espécies de algas aderidas às penas por indivíduo (ectozoocoria). Um número menor de espécies de algas também foi observado em culturas inoculadas com material oriundo das fezes das aves, caracterizando um potencial de transporte endozoocórico. Em relação ao aporte de nutrientes por colônia de garças-vaqueira, foi verificado uma alteração no teor de matéria orgãnica no sedimento localizado em áreas de poleiro como uma maior eutrofização da água nestas regiões. Foi observada também uma tendência a maior densidade de biomassa vegetal em bancos de macrófitas aquáticas utlizados como poleiro, com um conseqüente aumento na densidade de organismos associados às macrófitas aquáticas. Entretanto, não foram observadas diferenças significativas na fauna bentônica, ao se comparar as amostras de sedimento obtidas em pontos localizados na área de poleiro e área não-poleiro, mas foi constatado que essas colônias contribuem para o estoque de nutrientes nesses sistemas límnicos.

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22

Golléty, Claire. "Fonctionnement (métabolisme et réseau trophique) d'un système intertidal rocheux abrité, la zone à Ascophyllum nodosum, relation avec la biodiversité algale et animale." Paris 6, 2008. http://www.theses.fr/2008PA066451.

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L’objectif de ce travail de thèse était l’étude du fonctionnement de la zone à Ascophyllum nodosum, une ceinture algale caractéristique de la zone médiolittorale des estrans rocheux abrités des côtes de l’Atlantique Nord. Cette étude a permis d’établir (1) l’état des stocks d’A. Nodosum disponibles à la récolte le long des côtes de Bretagne et des communautés algales et animales associées ; (2) un bilan annuel de carbone de la zone à A. Nodosum hétérotrophe, dominé par le flux dus à la canopée ; (3) l’architecture générale du réseau trophique de la zone, basée sur l’utilisation de la plupart des sources de matière organique et pas seulement sur celle des principaux producteurs primaires ; (4) l’effet de la récolte partielle ou totale de la canopée sur la diversité spécifique, fonctionnelle et le métabolisme de la zone. Il a également été possible de comparer le métabolisme de la zone à celui d’autres ceintures algales voisines et à une zone dépourvue de canopée. Cette étude a permis de mieux préciser le rôle fonctionnel joué par la canopée sur la régulation de la biodiversité et sur le fonctionnement des estrans rocheux.

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23

Case, Rebecca Biotechnology &amp Biomolecular Sciences Faculty of Science UNSW. "Molecular- and culturebased approaches to unraveling the chemical cross-talk between Delisea pulchra and Ruegeria strain R11." Awarded by:University of New South Wales. School of Biotechnology and Biomolecular Sciences, 2006. http://handle.unsw.edu.au/1959.4/30394.

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Delisea pulchra is a red macroalga that produces furanones, a class of secondary metabolites that inhibit the growth and colonization of a range of micro- and macroorganisms. In bacteria, furanones specifically inhibit acyl homoserine lactone (AHL)- driven quorum sensing, which is known to regulate a variety of colonization and virulence traits. This thesis aims to unveil multiple aspects of the chemically mediated interactions between an alga and its bacterial flora. It was demonstrated that the quorum sensing genetic machinery of bacteria is laterally transferred, making traditional 16S rRNA gene based-diversity techniques poorly suited to identify quorum sensing species. Previous studies had shown that AHL-producing bacteria belonging to the roseobacter clade can be readily isolated from D. pulchra. Because of this, it was decided to use a roseobacter epiphytic isolate from this alga, Ruegeria strain R11, to conduct a series of colonization experiments on furanone free and furanone producing D. pulchra. Furanones were shown to inhibit Ruegeria strain R11's colonization and infection of D. pulchra. In addition, it was demonstrated that Ruegeria strain R11 has temperature-regulated virulence, similar to what is seen for the coral pathogen Vibrio shiloi. Rising ocean temperatures may explain bleached D. pulchra specimens recently observed at Bare Island, Australia. To assess whether quorum sensing is common within the roseobacter clade, cultured isolates from the Roseobacter, Ruegeria and Roseovarius genera were screened for AHL production. Half of the bacteria screened produced the quorum sensing signal molecules, AHLs. These AHLs were identified using an overlay of an AHL reporter strain in conjunction with thin layer chromatography (TLC). The prevalence of quorum sensing within the roseobacter clade, suggests that these species may occupy marine niches where cellular density is high (such as surface associated communities on substratum and marine eukaryotes). Diversity studies in marine microbial communities require appropriate molecular markers. The 16S rRNA gene is the most commonly used marker for molecular microbial ecology studies. However, it has several limitations and shortcomings, to which attention has been drawn here. The rpoB gene is an alternate ???housekeeping??? gene used in molecular microbial ecology. Therefore, the phylogenetic properties of these two genes were compared. At most taxonomic levels the 16S rRNA and rpoB genes offer similar phylogenetic resolution. However, the 16S rRNA gene is unable to resolve relationships between strains at the subspecies level. This lack of resolving power is shown here to be a consequence of intragenomic heterogeneity.

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24

Hodac, Ladislav Verfasser], Thomas [Akademischer Betreuer] Friedl, and Rolf [Akademischer Betreuer] [Daniel. "Green algae in soil: assessing their biodiversity and biogeography with molecular-phylogenetic methods based on cultures / Ladislav Hodac. Betreuer: Thomas, Friedl. Gutachter: Thomas, Friedl ; Rolf, Daniel." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2016. http://d-nb.info/1082128473/34.

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25

Timoner, Amer Xisca. "Stream biofilm responses to flow intermittency." Doctoral thesis, Universitat de Girona, 2014. http://hdl.handle.net/10803/283569.

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Streams experiencing a recurrent non-flow phase (i.e., flow intermittency) are characteristic of world regions with arid and semi-arid climates, where Mediterranean regions are part of. During non-flow streambed sediments, and consequently, microorganisms inhabiting these sediments are exposed to desiccation. These microorganisms, assembled in biofilms, lead a substantial part of the ecosystem processes. They recycle the carbon materials, intervene in the nutrient cycles and are on the base of the food web, fueling energy to the higher trophic levels. The aim of this tesis is to understand how biofilms respond to flow intermittency in order to unravel the consequences of the increasing spatial and temporal extent of flow intermittency, as a consequence of the global change, on the biogeochemical cycles and on the ecosystem functions in temporary streams. Structural and functional biofilm responses were analyzed at the cellular level (algae and bacteria), as well as at the whole biofilm responses (autotrophic vs heterotrophic processes) in two different field studies
Els rius que experimenten una fase sense cabal (intermitència fluvial) són característics de les regions del món amb climes àrids i semi-àrids, com ara les regions de la Mediterrànies. Durant la fase seca es produeix la dessecació de la llera del riu i conseqüentment els microorganismes que creixen sobre aquests sediments estan exposats a la dessecació. El conjunt d’aquests microorganismes es coneix com a biofilm, el qual juga un paper clau en el processament de la matèria orgànica i en els cicles del carboni i nutrients, A més són a la base de la xarxa tròfica aportant energia als nivells tròfics superiors. L'objectiu principal d'aquesta tesi és entendre el funcionament del biofilm quan es dona la fase seca, pas clau per entendre i predir les implicacions que tenen els períodes creixents sense cabal en els cicles biogeoquímics i en el funcionament de l’ecosistema. Les respostes estructurals i funcionals del biofilm des d’un punt de vista cel·lular (algues i bacteris), així com també en el conjunt del biofilm (processos autotròfics i heterotròfics) es van investigar mitjançant dos estudis de camp

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26

Mostert, Bruce Petrus. "Responses of intertidal macroalgae and associated fauna to interactive processes acting over multiple spatial scales." Thesis, Rhodes University, 2010. http://hdl.handle.net/10962/d1013370.

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The decrease of biological diversity from low latitudes near the equator towards high latitudes is one of the most fundamental patterns noted in ecology. These trends have been the subject of numerous terrestrial and marine studies and have caused the proposal of several explanatory hypotheses. No single hypothesis has adequately accounted for these observed trends. Furthermore, large-scale patterns are frequently modified by processes acting at meso- to small-scales. It is imperative to understand the interaction of these processes to elucidate the mechanisms controlling the structure of intertidal assemblages. The main aim of this thesis was to test the influence of multiple processes at a range of spatial scales on biogenic engineers. Biogenic engineers, such as macroalgae, have been reported to be strongly influenced by processes such as grazing, biogeography and upwelling and subsequent effects are expected to be linked to their associated assemblages. I used infaunal assemblages associated with macroalgae as a model system to understand the interactive effects of meso-scale upwelling in conjunction with large-scale factors (regional and biogeographic). Three species of macroalgae, Hypnea spicifera, Champia lumbricalis and Bifurcaria brassicaeformis, inhabiting different but overlapping home ranges were used in this study. Smaller scale, physical attributes and the associated fauna of these algal species were compared. The effects of meso- to large-scale physical gradients on marine organisms have been investigated in many instances and resultant gradients in physical variables observed. This study was undertaken to investigate morphological trends exhibited by Hypnea spicifera and Champia lumbricalis to compare possible similarities between coastlines and to determine if inferred meso- to large-scale processes influence physical trends in a similar manner despite the coastlines being affected by different hydrodynamic processes. The macroalgae were located in two distinctly different upwelling regimes, Hypnea spicifera on the east and south coasts and Champia lumbricalis on the west coast. Upwelling (delivery of nutrients and primary production) was not found to be an important factor in determining the physical characteristics of macroalgae but there were clear patterns linked to latitude. Mean percentage cover of Hypnea spicifera was positively correlated with distance along the east and south coasts. Mean mass and mean surface area of H. spicifera were, however, negatively correlated with distance from Port St Johns. Mean frond length showed a negative trend but this relationship was not statistically significant. On the west coast, there was a significant increase in mean frond length from north to south for Champia lumbricalis. Mean surface area and mean mass of C. lumbricalis exhibited non-significant negative trends from north to south while there was a non-significant positive trend for mean percentage cover. Following the “Productivity Hypothesis”, these patterns from north to south along the coastlines of South Africa could have important implications for biodiversity associated with these algae. Many previous studies have focussed on the effects of upwelling on species (i.e. effects of nutrients and temperature) but have failed to separate this effect from large scale effects such as biogeography and latitudinal gradients. I tested the influence meso-scale upwelling, large-scale biogeographic processes and latitudinal gradients with two different species of macroalgae one on the east and south coasts of South Africa and the other on the west coast. Hypnea spicifera inhabits the east and south coasts of South Africa spanning two biogeographic provinces and is generally affected by relatively weak upwelling, whereas Champia lumbricalis inhabits the west coast spanning one biogeographic province which is subjected to intense persistent upwelling year round. Within the east and west coast biogeographic provinces there are, however, regions with both upwelling and non-upwelling. On the east and south coasts, entire assemblages differed significantly among the three Regions (St Lucia, Port Alfred and Knysna, while assemblages between upwelling/non-upwelling areas were not different. Assemblages on the different shores differed significantly from each other. There were no significant effects of region or upwelling for the number of individuals of Crustacea or Polychaeta, while Mollusca showed a significant effect of region. The number of individuals of other taxa showed a significant interaction of region and upwelling. Region had a significant effect on number of species of molluscs and other taxa, while there was no effect for either region or upwelling for the Crustacea or Polychaeta. In general different factors were shown to be important (region and shore) while upwelling was rarely important. On the west coast assemblages associated with C. lumbricalis were not influenced by region or upwelling but there were significant differences between shores. Region, upwelling ad shore did not affect number of individuals. There was a significant interaction of region and upwelling for the number of species of crustaceans, while numbers of species of Mollusca, Polychaeta and other taxa showed no effects. In general, regional factors strongly influenced most organisms, while upwelling played a minor role. Hypotheses about differences between upwelling and non-upwelling regions in terms of species abundances and composition due to the input of cold nutrient rich water were not supported. A link between the effects of larger-scale biogeographic factors and their influence on habitat forming taxa and the resultant effects on associated infauna would be a likely explanation for the patterns observed in this study. Diversity of assemblages is known to be influenced by the structural complexity of a habitat, increasing complexity increases the amount of available niches therefore potentially increasing the number of species found within that habitat. Three species of macroalgae, Hypnea spicifera, Champia lumbricalis and Bifurcaria brassicaeformis were selected on the basis of being structurally similar and having their distributional ranges overlap in order to elucidate the effects of structure and macroalgal species on associated assemblages. Hypnea spicifera is different in terms of surface area and biomass from Champia lumbricalis and Bifurcaria brassicaeformis. Assemblages of species found on the three rhodophytes showed both shore and the species of alga had significant effects on composition. Only numbers of individuals of molluscs were affected by the species of alga. Crustacea and Polychaeta showed an interaction of the species of alga with shore. In the case of this study, it is likely that the three species of macroalgae mitigate biological stressors such as predation and physical stressors such as wave exposure and desiccation. In general, meso-scale upwelling is suggested to be marginalised when considering the structuring of assemblages associated with macroalgae, while large scale biogeography has more of an influence. Within shores, assemblages were also strongly influenced by smaller-scale factors such as differences in the structure and species of alga. This study indicates the importance of investigating patterns across a range of spatial scales to gain a comprehensive understanding of factors influencing intertidal organisms.

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Lydon, Anniken. "Identification of Saccharina groenlandica (Phaeophyceae) around the Svalbard Archipelago: DNA barcoding using cytochrome c oxidase subunit 1 (COI)." DigitalCommons@CalPoly, 2015. https://digitalcommons.calpoly.edu/theses/1368.

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In the Arctic, brown algae (kelps) and seaweeds are ecologically important: providing habitat, protection, and nutrients for invertebrate and vertebrate species living in nearshore environments. Migrations of biota between the North Pacific and North Atlantic Oceans have occurred periodically during Earth’s history leading to colonization of the Arctic Ocean. Around 3.5 Mya the “Great Trans-Arctic Biotic Interchange” occurred and the Laminariales order of kelp, thought to be of North Pacific origin, underwent a massive radiation and speciation event around the Arctic Ocean. Phylogenetic analysis performed on “Laminaria-like” specimens collected from six sampling locations around the Svalbard Archipelago identified both the presence of Saccharina groenlandica and Laminaria digitata. This research represents new records for the presence of S. groenlandica around the Svalbard Archipelago. S. groenlandica and L. digitata exhibit phenotypic similarities such that these two species can be difficult to tell apart in the field. In this study we have shown that the COI gene region can be used for DNA barcoding and can provide species level resolution between these two cryptic species. Prior to this study and Lund (2014), a number of biodiversity studies conducted around the Svalbard Archipelago identified the presence of L. digitata in a number of locations around the archipelago, however S. groenlandica was not identified in any of these prior studies. Phylogenetic analysis conducted here showed that all Svalbard specimens of S. groenlandica had identical COI sequences and up to 0.30% sequence diversity with S. groenlandica specimens from other parts of the Arctic Ocean. Further analysis is needed to understand the abundance of this newly recorded species around the archipelago and to investigate both the timing of arrival and mechanisms of colonization.

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28

Serebryakova, Alexandra. "Acclimation and adaptation of invasive seaweeds - a case study with the brown alga Sargassum muticum." Doctoral thesis, Paris 6, 2017. http://hdl.handle.net/10400.1/10824.

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Non-indigenous seaweeds impact natural communities worldwide, affecting biodiversity, ecosystem functioning, and ecosystem services, resulting in significant economic and social consequences. Among major impacts are the displacement of native species, a threat to endangered species, and effects on ecological and evolutionary processes within the invaded communities. While critical to predict the fate of introduced species, understanding the mechanisms of acclimation and adaptation following introduction represents a great challenge in seaweeds. In this thesis, we investigated some acclimation processes, with an emphasis on the role of associated microbiota, and examined their effects with Sargassum muticum as a model species. This brown seaweed native to Asia, is an emblematic invader among seaweeds, with a distribution now ranging from Mexico to Alaska in America and from Morocco to Norway in Europe. We first reviewed the competitive advantages and traits that may contribute to its invasiveness. In addition, we provided an overview of putative underlying mechanisms of acclimation and adaptation and highlighted their role in seaweed invasions. We then examined the effects of ocean acidification on the microbiome of S. muticum and revealed that it does not have significant effects on the seaweed-associated microbiota despite certain changes in the microbial community. We further investigated the seasonal changes in the seaweed-associated microbiota and revealed significant differences between seasons and geographic locations. Finally, we applied ecological niche modelling, but innovatively accounting for phenology, to project the distribution of S. muticum under two future climate change scenarios. According to our projections, by 2100 the distribution of S. muticum is expected to shift northwards along its European, North American and Asian distributions with a partial retreat from the currently occupied areas.
As algas não indígenas afetam comunidades naturais em todo o mundo, afetando a biodiversidade, o funcionamento dos ecossistemas e os seus serviços, com consequências económicas e sociais significativas. Entre os principais impactos estão deslocamento de espécies nativas e espécies ameaçadas e efeitos sobre processos ecológicos e evolutivos nas comunidades invadidas. A compreensão dos mecanismos de aclimatação e adaptação após a introdução representa um grande desafio nas algas marinhas. Nesta tese investigamos alguns processos de aclimatação, com ênfase no papel dos microorganismos associados e examinamos os seus efeitos usando Sargassum muticum como espécie modelo. Esta alga marinha nativa da Ásia é uma importante invasora, com uma distribuição atual do México ao Alasca na América e de Marrocos à Noruega na Europa. Primeiro analisamos as vantagens e características competitivas que podem contribuir para sua invasibilidade. Além disso, fornecemos uma visão geral dos mecanismos de aclimatação e adaptação subjacentes e destacamos seu papel nas invasões de algas marinhas. Em seguida, examinamos os efeitos da acidificação dos oceanos no microbioma de S. muticum e revelamos que não tem efeitos significativos sobre a comunidade microbiana das algas marinhas apesar de causar algumas mudanças na comunidade. No estudo das mudanças sazonais na microbiota associada às algas marinhas revelamos diferenças significativas entre as estações e os locais geográficos. Finalmente, realizamos modelação de nicho ecológico de forma inovadora para a fenologia, para projetar a distribuição de S. muticum em dois cenários futuros de mudança climática. De acordo com nossas projeções, até 2100, a distribuição de S. muticum deverá expandir-se para norte ao longo das suas distribuições européia, norte-americana e asiática, com retração parcial das áreas atualmente ocupadas.

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Alves, Luís Filipe Feio. "Os organismos marinhos como fonte de compostos bioativos." Master's thesis, [s.n.], 2014. http://hdl.handle.net/10284/4850.

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Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Ciências Farmacêuticas
A exploração dos organismos marinhos começou em meados do século XX pela Industria Farmacêutica e as Universidades, mas é no século XXI que atinge o seu expoente máximo na pesquisa de novos organismos como fonte de compostos bioativos, onde as Empresas de Biotecnologias dão um importante contributo. Se essas pesquisas inicialmente se basearam em organismos marinhos como fonte de compostos bioativos com potencial farmacológico, com o evoluir das pesquisas foi possível perceber que estes organismos possuíam também um potencial cosmético, cosmecêutico e nutracêutico. Neste trabalho, através da revisão bibliográfica, pode constatar-se que as algas marinhas, os moluscos, as esponjas e as ascídias apresentam o maior potencial de novas moléculas e metabolitos secundários, muito importantes no tratamento de várias patologias como o cancro, o herpes, a SIDA e no tratamento da dor. Os produtos cosmecêuticos e de cosmética têm como objetivo, a prevenção e o tratamento dermatológico através de compostos antioxidantes, hidratantes e anti idade. Já os produtos nutracêuticos e suplementos alimentares são importantes na dieta alimentar quotidiana dos seres humanos, na prevenção de doenças cardiovasculares através da ingestão de alimentos funcionais que não só previnem doenças como são uma fonte de saúde e bem-estar. The harvesting of marine organisms begains in mid-twentieth century with the Pharmaceutical Industry and Universities to lead, but it is in the twenty-first century that reaches its peak in search of new organisms as a source of bioactive compounds, where Biotechnology Companies make an important contribute. If these surveys are based initially on the research of marine organisms as a source of bioactive compounds with pharmacological potential for the evolution of the research it was revealed that these organisms also have cosmetic, cosmoceutical and nutraceutical potential. In this paper, through literature review, it can be seen that the seaweeds, clams, sponges and sea squirts have the greatest potential for new molecules and secondary metabolites, important in treating various diseases such, herpes and AIDS, and for the treatment of pain. Cosmeceuticals and cosmetic products aim, the prevention and dermatological treatment by antioxidants, moisturizers and anti-aging. Already nutraceuticals and dietary supplements are important in the daily diet of humans, in the prevention of cardiovascular disease through ingestion of functional foods that not only prevent disease as they are a source of health and well-being.

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Karasiewicz, Stéphane. "The phytoplankton community response(s) to global changes and their effect(s) on ecosystem functioning with a special focus on Phaeocystis spp, a harmful algae." Thesis, Lille 1, 2017. http://www.theses.fr/2017LIL10191/document.

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Les écosystèmes côtiers, interface entre terre et mer, sont soumis au changement climatique ainsi qu’à de fortes pressions anthropiques. Par conséquent, les eaux côtières sont sujettes à eutrophisation. Le phytoplancton demande une attention particulière dû à son rôle de producteur primaire des écosystèmes marins. Récemment, l’efflorescence des algues nuisibles est devenue mondialement, une inquiétude croissante. Le but de la thèse a été de décrire et de mesurer les réponses temporelles et les causalités de la structure de communauté phytoplanctonique sous impact des changements globaux, en présence d’une algue nuisible. Pour ce faire, le concept de niche écologique et une méthode statistique, ont été adaptés. Les "Within Outlying Mean Indexes" ont été proposés pour affiner l’analyse "Outlying Mean Index" en combinant ses propriétés avec la décomposition de la marginalité de l’analyse "K-select". Les dynamiques des sous-niches de la communauté d’espèce ont été étudiées dans des conditions environnementales d’ abondances basses (L) ou fortes (H) de Phaeocystis spp. Le sous-ensemble H était caractérisé par une large niche de Phaeocystis spp. ainsi qu’une forte diversité de diatomées. Dans le sous-ensemble L, Phaeocystis spp. a subit une forte contrainte biologique probablement induite par la compétition des diatomées pour les ressources. La relation diversité-productivité du phytoplancton s’est avérée plus forte à l’échelle saisonnière que sur le long-terme. Le déséquilibre des ressources n’a pas eu de lien direct avec la productivité à long terme. Le succès à long terme de l’espèce invasive et de son impact sur la productivité, est favorisé par une suite d’années froides avec des ressources élevées et déséquilibrées, augmentant le nombre de petites espèces de diatomées et donc son efflorescence. Enfin, je discute des améliorations méthodologiques, du potentiel d’utilisation de l’approche par traits, et d’éventuelles montages expérimentaux pour supporter les résultats de la thèse
Coastal ecosystems, the interfaces between land and sea, are subject to climate change and high anthropogenic pressure. Consequently, most coastal waters are prone to eutrophication. The phytoplankton require a special attention because of its role of primary producer in marine ecosystems. Recently, Harmful Algae Bloom outbreaks has raised concern worldwide. The thesis aim was to describe and to measure the temporal responses and causalities of the phytoplankton community structure, with the occurrence of a harmful algae, under global changes. To do so, the ecological niche concept and a statistical method were adapted. The Within Outlying Mean Indexes was proposed to refine the Outlying Mean Index analysis by combining its properties with the K-select analysis species marginality decomposition. The subniche dynamics of the species composing the community were studied under environmental conditions hosting low (L) and high (H) Phaeocystis spp. abundance. Subset H was characterized by a large Phaeocystis spp. niche and a high diatom diversity. In subset L, Phaeocystis spp. was subject to great biological constrain suspected to be caused by diatom competition for resources. The phytoplankton diversity productivity was stronger at a seasonal scale than on the long-term. The resource imbalance had no direct link with productivity in the long-term. The long-term invasive species success and its impact on productivity is favored by successive cold years with high resource imbalance which rise the number of small species and its bloom. I finally discussed on the methodological improvements, the potential use of the trait-based approach, and possible experimental set-ups to support the thesis results

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Ricart, Viladomat Marta. "Effects of priority and emerging pollutants on river biofilms." Doctoral thesis, Universitat de Girona, 2011. http://hdl.handle.net/10803/7881.

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L'activitat humana representa una de les majors causes d'entrada d'una gran varietat de substàncies en els ecosistemes fluvials. L'objectiu principal d'aquest treball es investigar els efectes que els tòxics orgànics poden exercir en els biofilms fluvials. El riu Llobregat ha estat sotmès a fortes pressions, fet que l'ha portat a uns nivells molt elevats de contaminació. En aquest estudi s'ha observat una influència dels plaguicides presents al riu en la distribució de la comunitat de diatomees, així com efectes en el biofilm a nivell funcional i estructural. Experiments amb canals experimentals han mostrat que l'herbicida diuron i el bactericida triclosan poden ocasionar una cadena d'efectes en els biofilms, incloent efectes directes i també efectes indirectes en les relacions entre els components del biofilm. Experiments amb cultius algals han mostrat que aquests tòxics, aplicats en barreja, poden tenir una major toxicitat de la prevista pels models, resultant en efectes sinèrgics.
Human activity is responsible for the entrance of many substances to the aquatic environment. The main objective of this study is to investigate the effects of organic toxicants on fluvial biofilms. The river Llobregat has been submitted to urban, industrial and agricultural pressures, and as such is a highly contaminated river. The diatom community was influenced by the presence of pesticides. Effects on both biofilm function and structure were attributed to the pesticides. Laboratory experiments with experimental channels have shown that the herbicide diuron and the bactericide triclosan may cause a chain of effects on biofilms, which include direct effects and indirect effects on the relationship between biofilm components. Experiments with algal cultures have shown that these toxicants, applied in mixtures, can have higher toxicity than the toxicity predicted by models, resulting in synergistic effects.

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Serebryakova, Alexandra. "Acclimation and adaptation of invasive seaweeds - a case study with the brown alga sargassum muticum." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066475.

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Les algues non-indigènes ont des impacts sur les communautés naturelles à une échelle mondiale: elles affectent la biodiversité et le fonctionnement des écosystèmes ainsi que les services écosystémiques, avec des conséquences économiques et sociales. Parmi les conséquences de ces introductions sont le déplacement d'espèces indigènes, des compétitions avec des espèces en danger et des effets sur les trajectoires éco-évolutives des espèces des communautés envahies. Bien que crucial pour anticiper le devenir des espèces non-indigènes, comprendre les mécanismes d'acclimatation et d'adaptation agissant post-introduction reste un challenge chez les algues. Au cours de cette thèse, nous avons étudié certains processus d'acclimatation, en particulier le rôle des bactéries associées, et leurs effets, en utilisant comme modèle d'étude Sargassum muticum. Cette algue brune originaire d'Asie, est une espèce emblématique parmi les algues introduites avec une présence du Mexique à l'Alaska en Amérique et du Maroc à la Norvège en Europe. Nous avons effectué une analyse bibliographique des traits et caractéristiques écologiques qui pourraient expliquer son succès. Nous avons ensuite montré que l'acidification n'a pas d'effets significatifs sur les bacteries associées, bien que des changements saisonniers du microbiome aient été observés. Enfin, nous avons utilisé un modèle de niche écologique, intégrant la phénologie, pour prédire la distribution de S. muticum sous deux scénarios de changement climatique. Selon nos résultats, d'ici 2100, la distribution de S. muticum devrait se déplacer vers le nord dans l'hémisphère nord avec des régressions dans certaines zones actuellement occupées
Non-indigenous seaweeds impact natural communities worldwide, affecting biodiversity, ecosystem functioning, and ecosystem services, resulting in significant economic and social consequences. Among major impacts are the displacement of native species, a threat to endangered species, and effects on ecological and evolutionary processes within the invaded communities. While critical to predict the fate of introduced species, understanding the mechanisms of acclimation and adaptation following introduction represents a great challenge in seaweeds. In this thesis, we investigated some acclimation processes, with an emphasis on the role of associated microbiota, and examined their effects with Sargassum muticum as a model species. This brown seaweed native to Asia, is an emblematic invader among seaweeds, with a distribution now ranging from Mexico to Alaska in America and from Morocco to Norway in Europe. We first reviewed the competitive advantages and traits that may contribute to its invasiveness. We then showed that acidification has no significant effects on associated bacteria, although seasonal changes in the microbiome have been observed. Finally, we applied ecological niche modelling, but innovatively accounting for phenology, to project the distribution of S. muticum under two future climate change scenarios. According to our projections, by 2100 the distribution of S. muticum is expected to shift northwards along its European, North American and Asian distributions with partial retreat from the currently occupied areas

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Rasher, Douglas B. "Chemically mediated competition, herbivory, and the structure of coral reefs." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/49019.

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Corals, the foundation species of tropical reefs, are in rapid global decline as a result of anthropogenic disturbance. On many reefs, losses of coral have coincided with the over-harvesting of reef herbivores, resulting in ecosystem phase-shifts from coral to macroalgal dominance. It is hypothesized that abundant macroalgae inhibit coral recovery and recruitment, thereby generating ecological feedback processes that reinforce phase-shifts to macroalgae and further diminish reef function. Notwithstanding, the extent to which macroalgae directly outcompete coral, the mechanisms involved, and the species-specificity of algal-coral competition remains debated. Moreover the capacity for herbivores to prevent vs. reverse ecosystem phase-shifts to macroalgae and the roles of herbivore diversity in such phenomena remain poorly understood. Here I demonstrate with a series of field experiments in the tropical Pacific and Caribbean Sea that multiple macroalgae common to degraded reefs directly outcompete coral using chemical warfare, that these interactions are mediated by hydrophobic secondary metabolites transferred from algal to coral surfaces by direct contact, and that the outcomes of these allelopathic interactions are highly species-specific. Using field observations and experiments in the tropical Pacific, I also demonstrate that the process of herbivory attenuates the competitive effects of allelopathic algae on corals by controlling succession of algal communities, and that the herbivore species responsible for macroalgal removal possess complementary tolerances to the diversity of chemical defenses deployed among algae, creating an essential role for herbivore diversity in reversing ecosystem phase-shifts to macroalgae. Lastly, I demonstrate with field experiments in the tropical Pacific that algal-coral competition simultaneously induces allelochemicals and suppresses anti-herbivore deterrents in some algae, likely due to trade-offs in the productions of defense metabolites with differing ecological functions. Together, these studies provide strong evidence that chemically mediated competitive and consumer-prey interactions play principal roles in coral reef degradation and recovery, and should provide resource managers with vital information needed for effective management of these ecologically and economically important but threatened ecosystems.

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Ololo, Gustave. "A limnological study of factors affecting algal biodiversity in the Hartbeespoort Dam." Thesis, 2014. http://hdl.handle.net/10210/11378.

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M.Sc. (Aquatic Health)
The relationships between water quality variables and phytoplankton diversity in the Hartbeespoort Dam were assessed spatially and temporally from February 2011 to March 2012 to evaluate the effects of the water quality variables on cyanobacterial bloom (Microcystis aeruginosa) hence aquatic macrophytes growth (Eichhornia crassipes) in the dam. Variables measured using standard methods included; temperature, pH, electrical conductivity, total suspended solids, dissolved oxygen, nitrate, nitrite, total phosphorous , ammonium, trace metals, chlorophyll-a and the phytoplankton community. The physical parameters ranged between: temperature (11.8-28 oC), electrical conductivity (282-796 ƒÊS/cm), dissolved oxygen (0.33-32.2 mg/L), pH (6.95-9.91) and total suspended solids (2-372 mg/L). Chemical variables ranged between; total phosphorous (0.02-3.5 mg/L), nitrate (0.03-21.2 mg/L), nitrite (0.02-0.48 mg/L) and ammonium (0.01-1.58 mg/L), chlorophyll-a (0.13-8693 ƒÊg/L), and exceed the TWQR values of the South African Water Quality Guidelines for aquatic ecosystem health health. Metal concentrations in water had the following decreasing order; macro elements: potassium > calcium >sodium > magnesium. Microelements: iron >zinc > aluminium > copper > nickel > manganese > chromium> selenium > lead > silver > arsenic > cadmium. Iron had the highest concentration among microelement of 631.62 ƒÊg/L and potassium the highest concentration amongst macro element of 34.49 mg/L. Six Different algal divisions were found in the dam with cyanophyta (cyanobacteria) been the most dominant group (95 %) and M.aeruginosa the most dominant species (69 %). The current study revealed an increase in physical parameters, chlorophyll-a and phytoplankton community and a decrease in chemical parameters in the summer months. An inverse relationship was observed in the winter months at all sites. One-way ANOVA showed a significant differences for physical variables (p <0.05) between months, with no significant differences noted (p > 0.05) between sites and between depths. Chemical variables however, showed a significant differences between months, sites and between depths (p <0.05). A 2-tailed Pearson correlation revealed negative correlations between temperatures and phosphorus, ammonia, nitrate, nitrite, electrical conductivity and iron (r=-0.298;-0.232;-0.099;-0.461;-0.441;-0.260) respectively and positive correlations between temperatures and chlorophyll-a and pH (r= 0.240; 0.609 ;) respectively (p <0.05; p <0.01). Canonical discriminant functions analysis revealed similarities and dissimilarities in water quality variables temporally and spatially with eigenvalues of 84.6 % and 59.1 % respectively. There was an adverse impact of the physico-chemical variables on the phytoplankton community, therefore aquatic macrophytes growth in the dam. The current study revealed that temperature, pH, phosphorous, nitrate and probably iron, copper, zinc and selenium may have contributed to the hypertrophic state of the dam, hence cyanobacterial bloom and growth of aquatic macrophytes.

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Chien, Yu-Ching, and 簡鈺晴. "Analyses of Algal Biodiversity and Modeling the Dynamics of Phytoplankton Succession in Feitsui Reservoir." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/69831135563135340146.

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碩士
國立臺灣大學
環境工程學研究所
93
Water quality in reservoirs is an important issue of concern in terms of water supply nowadays. Eutrophication is a prevailing problem threating the water quality of reservoirs in Taiwan. The ability to forecast the tendency of phytoplankton growth must be established, then the actions to prevent eutrophication can be taken. There is great number of phytoplankton species in nature water bodies, and many factors interactively affect their growth. How they affect the growth of phytoplankton was examined in this study. First, the relationships between phytoplankton growth and environmental factors must be identified. Feitsui Reservoir is a model water body uesd to study the relationships described above. Second, whether environment gradient is benefitial to biodiversity or not, sampling and modeling must be done in this study to determine. Sampling at different depth in Feitsui Reservoir was undertaken to know the spatial distribution characteristics of water quality, phytoplankton and zooplankton growth. A conceptual model including stratified system was established to mimic the reservoir water column, which showed gradients of environmental factors. According to the statistic analysis, it was found that seasonal growth and decline of algae were related to physical environmental factors which change seasonally. The mobility of phytoplankton and the water column mixing condition are both instrumental in creating the environment of phytoplankton growth. The biodiversity index, Shannon-Wiener Index, was related to temperature gradient according to the results of statistic analyses. From the simulating results of total amount of algae, phosphorus supply was found an important factor for growth. The model of coexistence of three types of algae is able to simulate algal succession. Periodically water mixing is the driving force of algal succession and beneficial to algae coexistence.

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Hallmann, Christine. "Biodiversity of terrestrial algal communities from soil and air-exposed substrates using a molecular approach." Doctoral thesis, 2015. http://hdl.handle.net/11858/00-1735-0000-0028-86EF-4.

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CHOPRA, VIVEK. "ALGAL BIODIVERSITY BASED RECONSTRUCTION OF THE PAST LOCAL AND REGIONAL ENVIRONMENTAL CONDITIONS OF RIVER YAMUNA IN DELHI REGION." Thesis, 2020. http://dspace.dtu.ac.in:8080/jspui/handle/repository/18099.

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River Yamuna is one of the most essential river of India originating from the Yamunotri glacier in Himalayas from a height of 6387 meters and travelling a total length of 1,376 kilometres before it merges in river Ganga. A majority of population depends on river Yamuna for their daily needs. Yamuna enters in Delhi at Palla village covering a stretch of 48 kilometres. This is where it receives huge amount of pollutants as sewage and industrial disposals. However, it is assumed that river Yamuna was clean and in good health during earlier times. Therefore, the present research is the first attempt to study the paleolimnological conditions of river Yamuna using river bed sediments for radioactive Carbon-14 dating and using diatom diversity as an indicator of paleolimnological conditions . Two sites were selected for the research work, SITE A Palla village of Delhi where Yamuna enters in Delhi and SITE B was near Okhla barrage which is present almost at the last stretch of Yamuna in Delhi. SITE A, Palla village is present far from urban population of Delhi and surrounded by agricultural fields while Okhla barrage is located in vicinity of a outsized human population where it receives a massive amount of pollution through sewage and industrial wastes. A total of 18 river sediment samples were taken at different depths from both the sites in which 9 samples were from SITE A and 9 samples from SITE B. Diatoms have been an essential component of paleolimnological assessments for a variety of reasons, which includes their well-preserved siliceous frustules, their ability to respond swiftly to variations in the environment and their distribution among a varied range of water quality gradients. Therefore, diatom assemblage of particular vi sediment from river bed was used to reveal ecological conditions of a particular time frame observed by radiocarbon 14C analysis. A total of 31 species of diatom was observed from the riverbed sediments. Each sample revealed almost different diversity of diatoms. The ecological indicators like pH, trophic state, Nitrogen uptake, oxygen and moisture requirements which are very unique for every diatom taxa were used to reveal environmental conditions of the river Yamuna in prehistoric times using the sediments collected from river bed. Other experiments like SEM-EDAX, CHNS analysis, XRD and XRF analysis were also performed to study the geochemical nature of sediments. Different elements like Si, O, Al, Nb were recorded from river sediments by EDAX analysis, while CHNS analysis helped in analyzing the concentrations of Carbon, Hydrogen, Nitrogen and Sulphur. The nature of mineral composition is studied with the help of XRD which revealed Quartz as the major mineral present at both the Sites. XRF revealed most of the oxides, trace elements and some heavy metals from the riverbed sediments. Various oxides and trace elements which are found in XRF analysis are Al2O3, CaO, Fe2O3, K2O, MgO, Na2O, P2O5, SiO2, TiO2, Th, MnO, Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Zr, Ba, Pb. The correlation of these oxides and trace metals is an efficient way to study chemical nature of river Yamuna sediments. Paleolimnological and geochemical data revealed from sediments could be of great significance for understanding complex nature of river sediments components, diatom diversity and ecology and hence in conservation of river.

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Dixon, Kyatt R. "Diversity and systematics of Peyssonneliaceae (Rhodophyta) from Vanuatu and southeastern Australia." 2010. http://repository.unimelb.edu.au/10187/8508.

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The thesis investigates members of the crustose and largely calcified red algal family Peyssonneliaceae through molecular analyses and anatomical and ultrastructural observations. Mitochondrial CO1 DNA barcoding was implemented, in combination with fine-scale anatomy, to recognise species boundaries and identify complexes of cryptic species. Nuclear and organellar DNA markers were employed to construct a multigene phylogeny for Vanuatu and southern Australian members of the family facilitating the recognition of two undescribed genera Annea and Incendia.

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Hodac, Ladislav. "Green algae in soil: assessing their biodiversity and biogeography with molecular-phylogenetic methods based on cultures." Doctoral thesis, 2016. http://hdl.handle.net/11858/00-1735-0000-0028-86B5-4.

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Lin, Ching-Su, and 林敬舒. "Biodiversity and physiological responses to water stress of soil algae in biological soil crusts in highly eroded badlands of central Taiwan." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/71872125940000133565.

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博士
國立臺灣大學
生態學與演化生物學研究所
102
This study was aimed to characterize the diversity, abundance, phylogeny, and stress physiology of indigenous soil algae at highly eroded badlands, including Dadu, Dakeng, and Hoyen Mountain situated in mid-Taiwan and to elucidate the feasibility of establishing biological soil crusts (BSCs). At Hoyen Mountain and Dadu, dominant soil algae were of chlorophytes including those genera of Bracteacoccus, Coccomyxa, Klebsormidium, and Koliella, while at Dakeng of cyanobacteria such as Leptolyngbya. The distribution of soil algae exhibited a strong dependency on environmental variables such as soil moisture, soil texture, and the vegetation type. For phylogenic analysis of soil algae, both the 16S rDNA and plastid 23S rRNA were used. The results showed that these algae belonged to an evolution complex. To study the physiology of water stress in soil algae, polyethylene glycol (PEG) was used as an inducer. As a response to PEG treatment, the intracellular proline levels were elevated, which was associated with increases in malondialdehye (MDA), pigment contents, and activities of antioxidant enzymes such as superoxide dismutase (SOD). As a result, the tolerance to water stress could be indicated by the intracellular levels of proline, SOD, and caroteniods. Moreover, to test the establishment of BSCs, L. boryana was used. The development of BSCs resulted from this organism would improve remarkably the biological and physiso-chemical properties of the soil environment. The establishment of BSCs could be differentiated into five stages, namely initial, mature, extended, contended, and declined. The time of establishment varied with environmental factors at the habitat. It was suggested that filamentous L. boryana may be a suitable pioneer organism for BSCs establishment and restoration of the disturbed environments.

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莊博雅. "Exploring the learning effect of the supplementary text “Buried Treasure Forest of Dragon King” integrated to the high school basic biology “the biodiversity- algae” unit." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/01245719704113316715.

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碩士
國立彰化師範大學
生物學系
100
Abstract The purpose of this research is to explore the achievement of “Buried Treasure Forest of Dragon King” supplementary text integrated to the high school basic biology “the Biodiversity- Algae” unit in different teaching strategies of the tenth grade students. The feeling of student's study also explored. A quasi-experimental design was conducted with junior high school students of 10th grade in the central Taiwan. The experimental group included two classes of 75 participants carried on the cooperation study and the control group also included two classes of 74 participants carried on the traditional teaching. Two groups all used the supplementary text of “Buried Treasure Forest of Dragon King”. After carried on three classes, all students received the achievement test and filled the feeling questionnaire. The research tools included Algae supplementary text- “Buried Treasure Forest of Dragon King”, ”Achievement Test”, “The Biodiversity Curricula Integrated with “Buried Treasure Forest of Dragon King” Supplementary Text's Feeling Questionnaire”. Student’s learning achievement was measured by pre-test, and post-test. The data were analyzed by using t test for dependent means, and t test for a single sample. The results revealed that the cooperation study strategy may promote student's achievement. There was no remarkable difference on the cooperation study strategy in genders. In this research, the achievement of the female student progressed much than male. The analysis of the questionnaire showed that two group participants both like “Buried Treasure Forest of Dragon King” supplementary text and they thought that the supplementary text can promote their algae's knowledge.

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Dissertations / Theses on the topic 'ALGAL BIODIVERSITY'

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