Academic literature on the topic 'Algal feeding'
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Journal articles on the topic "Algal feeding"
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McAuley, P. J. "The cell cycle of symbiotic Chlorella. I. The relationship between host feeding and algal cell growth and division." Journal of Cell Science 77, no. 1 (August 1, 1985): 225–39. http://dx.doi.org/10.1242/jcs.77.1.225.
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When green hydra were starved, cell division of the symbiotic algae within their digestive cells was inhibited, but algal cell growth, measured as increase in either mean volume or protein content per cell, was not. Therefore, control of algal division by the host digestive cells must be effected by direct inhibition of algal mitosis rather than by controlling algal cell growth. The number of algae per digestive cell increased slightly during starvation, eventually reaching a new stable level. A number of experiments demonstrated that although there was a relationship between host cell and algal mitosis, this was not causal: the apparent entrainment of algal mitosis to that of the host cells could be disrupted. Thus, there was a delay in algal but not host cell mitosis when hydra were fed after prolonged starvation, and algae repopulated starved hydra with lower than normal numbers of algae (reinfected aposymbionts or hydra transferred to light after growth in continuous darkness). Two experiments demonstrated a direct stimulation of algal cell division by host feeding. Relationships of algal and host cell mitosis to numbers of Artemia digested per hydra were different, and in hydra fed extracted Artemia algal, but not host cell, mitosis was reduced in comparison to that in control hydra fed live shrimp. It is proposed that algal division may be dependent on a division factor, derived from host digestion of prey, whose supply is controlled by the host cells. Numbers of algae per cell would be regulated by competition for division factor, except at host cell mitosis, when the algae may have temporarily uncontrolled access to host pools of division factor. The identity of the division factor is not known, but presumably is a metabolite needed by both host cells and algae.
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Figueiredo, Joana, Luís Narciso, Ralph Turingan, and Junda Lin. "Efficiency of using emerald crabs Mithraculus sculptus to control bubble alga Ventricaria ventricosa (syn. Valonia ventricosa) in aquaria habitats." Journal of the Marine Biological Association of the United Kingdom 88, no. 1 (February 2007): 95–101. http://dx.doi.org/10.1017/s0025315408000192.
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Ornamental crabs of the genus Mithraculus (Decapoda: Brachyura: Majidae) are utilized in reef aquaria to control nuisance algae, particularly bubble algae. Although Mithraculus have modified, spooned-shaped chelae to feed on both fleshy and filamentous algae, they may consume alternative foods offered in a reef aquarium. The objective of this study was to determine the efficiency of using Mithraculus sculptus to control the bubble alga Ventricaria ventricosa (Siphonocladales–Cladophorales complex, Chlorophyta) in the presence of alternative foods (commercial pellets and frozen mysids) commonly utilized in reef aquaria. Results indicated that medium and large sized crabs consumed more bubble algae than smaller conspecifics. Although, M. sculptus first chose alternative foods to bubble alga (77% and 69% of the time chose pellets and frozen mysids, respectively), algal consumption only decreased significantly if, besides algae, pellets were provided; when only algae were provided, algal consumption was similar to when they were provided with mysids. The prey choice model was used as a conceptual framework to study the mechanisms underlying active selection; food energy content and handling time were measured and food profitability was calculated. Handling time decreased with increasing crab size. Pellets presented a higher profitability than algae but mysids and algae presented similar profitability; this seems to be in agreement with the observed reduced algal consumption when pellets made part of the diet. Mithraculus sculptus feeding behaviour on V. ventricosa recorded with digital high-speed video (DHSV) suggests that as the crab tears the algal cell apart, the cell liquid that contains juvenile cytoplasmatic spheres is released into the water; this behaviour might contribute to algal dispersal and consequently algal infestation. These results seem to indicate that M. sculptus might not be such an efficient bio-controller of the pest V. ventricosa as previously thought, particularly when pellets are used as food; however, its bio-control efficiency might be improved if, mysids are used as food.
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Smith, Daniel Wilkins. "Biological Control of Excessive Phytoplankton Growth and the Enhancement of Aquacultural Production." Canadian Journal of Fisheries and Aquatic Sciences 42, no. 12 (December 1, 1985): 1940–45. http://dx.doi.org/10.1139/f85-240.
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A method is proposed to control phytoplankton biomass in aquacultural ponds, using both zooplankton and filter-feeding silver carp (Hypophthalmichthys molitrix). The technique maintains co-existence of zooplankton and filter-feeding fish by excluding the fish from part of the water column. Zooplankton, which feed on smaller algal species, and silver carp, which feed on large algae and zooplankton, together can consume all sizes of phytoplankton, thus controlling algal biomass. This technique was tested in 1000-L tanks, some containing channel catfish (Ictalurus punctatus) alone, some both catfish and silver carp, and others catfish and silver carp with a zooplankton refuge. The refuge permitted coexistence of high densities of large zooplankters with the filter-feeding fish. This combination of filter-feeders reduced algal biomass by as much as 99%, increased phytoplankton diversity, and showed a trend toward improved silver carp growth compared with treatments without a refuge. The proposed technique could be applied to both intensive and extensive aquacultural systems.
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DUNN, KENNETH. "Growth of endosymbiotic algae in the green hydra, Hydra viridissima." Journal of Cell Science 88, no. 5 (December 1, 1987): 571–78. http://dx.doi.org/10.1242/jcs.88.5.571.
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Stable endosymbiosis depends upon balanced growth of the symbionts. In green hydra, coincident patterns of host and algal mitotic index suggest that coordinated reproduction provides for balanced growth. However, when hydra shrink during food shortage, the population of endosymbiotic algae in a green hydra must likewise decline in size. Thus far, no mechanism of reducing the size of the endosymbiont population has been described. Algal mitosis was found here to be stimulated by host feeding and clumped in its distribution among host cells, supporting the notion of some degree of control of algal mitosis exercised at the level of the host cell. However, comparisons of the rates of algal mitosis with the realized rates of algal population growth show that substantial numbers of algae disappear from hydra, in numbers in excess even of those necessary to accommodate host shrinkage. Only a small proportion of these lost algae was found to be expelled by hydra. Microscopic observations of the cells of macerated hydra show evidence of algal disintegration in nearly 50 % of the digestive epithelial cells of regularly fed hydra. Coincidence of remnants of algal cells and food-derived materials within the same vacuoles suggests that algae are digested by host cells.
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Iken, K., E. R. Barrera-Oro, M. L. Quartino, R. J. Casaux, and T. Brey. "Grazing by the Antarctic fish Notothenia coriiceps: evidence for selective feeding on macroalgae." Antarctic Science 9, no. 4 (December 1997): 386–91. http://dx.doi.org/10.1017/s0954102097000497.
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In Potter Cove, King George Island, Antarctica, macroalgae provide a significant food resource for herbivores. The demersal fish Notothenia coriiceps feeds on macroalgae. Eighteen algal species were identified in stomach contents: two chlorophytes, ten rhodophytes and six phaeophytes. Among these the rhodophyte Palmaria decipiens, the phaeophyte Desmarestia menziesii and the chlorophyte Monostroma hariotii comprised the greatest proportions of algal biomass. A food selection study showed four algae to be preferred (P. decipiens, M. hariotii, D. menziesii, Iridaea cordata) and two species to be avoided (Desmarestia anceps and Himantothallus grandifolius) by N. coriiceps. The present investigation indicates that this fish feeds not only intentionally, but also selectively, on macroalgae. Preference for particular algal species is not related to associated epifaunal biomass or to associated amphipod biomass.
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Ngugi, David Kamanda, Sou Miyake, Matt Cahill, Manikandan Vinu, Timothy J. Hackmann, Jochen Blom, Matthew D. Tietbohl, Michael L. Berumen, and Ulrich Stingl. "Genomic diversification of giant enteric symbionts reflects host dietary lifestyles." Proceedings of the National Academy of Sciences 114, no. 36 (August 23, 2017): E7592—E7601. http://dx.doi.org/10.1073/pnas.1703070114.
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Herbivorous surgeonfishes are an ecologically successful group of reef fish that rely on marine algae as their principal food source. Here, we elucidated the significance of giant enteric symbionts colonizing these fishes regarding their roles in the digestive processes of hosts feeding predominantly on polysiphonous red algae and brown Turbinaria algae, which contain different polysaccharide constituents. Using metagenomics, single-cell genomics, and metatranscriptomic analyses, we provide evidence of metabolic diversification of enteric microbiota involved in the degradation of algal biomass in these fishes. The enteric microbiota is also phylogenetically and functionally simple relative to the complex lignocellulose-degrading microbiota of terrestrial herbivores. Over 90% of the enzymes for deconstructing algal polysaccharides emanate from members of a single bacterial lineage, “Candidatus Epulopiscium” and related giant bacteria. These symbionts lack cellulases but encode a distinctive and lineage-specific array of mostly intracellular carbohydrases concurrent with the unique and tractable dietary resources of their hosts. Importantly, enzymes initiating the breakdown of the abundant and complex algal polysaccharides also originate from these symbionts. These are also highly transcribed and peak according to the diel lifestyle of their host, further supporting their importance and host–symbiont cospeciation. Because of their distinctive genomic blueprint, we propose the classification of these giant bacteria into three candidate genera. Collectively, our findings show that the acquisition of metabolically distinct “Epulopiscium” symbionts in hosts feeding on compositionally varied algal diets is a key niche-partitioning driver in the nutritional ecology of herbivorous surgeonfishes.
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McAuley, P. J. "The cell cycle of symbiotic Chlorella241. II. The effect of continuous darkness." Journal of Cell Science 77, no. 1 (August 1, 1985): 241–53. http://dx.doi.org/10.1242/jcs.77.1.241.
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When green hydra were grown in continuous darkness the mean cell size of their symbiotic algae was smaller than when grown in light and numbers of algae per digestive cell were reduced. The former was due to a reduction in size at which the algae divided, and the latter to a loss of synchrony of algal mitosis with that of digestive cells after transfer to darkness. Eventually, algal mitosis regained synchrony with that of digestive cells. Division synchrony was not lost in reinfected hydra (with lower than normal numbers of algae per cell) transferred to darkness; this, and the observation that synchrony in normal animals transferred to darkness was regained when algal numbers per cell had fallen to a new, lower level, suggested that the initial inhibition of algal mitosis was due to competition for a limited supply of heterotrophically required metabolites. When dark-grown hydra were returned to light there was no delay in algal division and a steady increase in the size of dividing cells, suggesting that the smaller division size in darkness was not due simply to the critical size for division being set at a lower value. In light, algal division size varied with frequency of host feeding, but this had less effect on algal division size in darkness. It is suggested that the critical cell size that algae must attain before being able to complete the cell cycle is the same in light and darkness, but in light mitosis is restricted by some exogenous factor so that algae grow beyond the critical size without dividing. In darkness both algal cell growth and division are dependent on exogenously supplied metabolites, and cell growth rather than the division factor is limiting. The precise nature of the restriction on algal division remains unknown.
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Roach, Ty N. F., Mark Little, Milou G. I. Arts, Joel Huckeba, Andreas F. Haas, Emma E. George, Robert A. Quinn, et al. "A multiomic analysis of in situ coral–turf algal interactions." Proceedings of the National Academy of Sciences 117, no. 24 (June 1, 2020): 13588–95. http://dx.doi.org/10.1073/pnas.1915455117.
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Viruses, microbes, and host macroorganisms form ecological units called holobionts. Here, a combination of metagenomic sequencing, metabolomic profiling, and epifluorescence microscopy was used to investigate how the different components of the holobiont including bacteria, viruses, and their associated metabolites mediate ecological interactions between corals and turf algae. The data demonstrate that there was a microbial assemblage unique to the coral-turf algae interface displaying higher microbial abundances and larger microbial cells. This was consistent with previous studies showing that turf algae exudates feed interface and coral-associated microbial communities, often at the detriment of the coral. Further supporting this hypothesis, when the metabolites were assigned a nominal oxidation state of carbon (NOSC), we found that the turf algal metabolites were significantly more reduced (i.e., have higher potential energy) compared to the corals and interfaces. The algae feeding hypothesis was further supported when the ecological outcomes of interactions (e.g., whether coral was winning or losing) were considered. For example, coral holobionts losing the competition with turf algae had higher Bacteroidetes-to-Firmicutes ratios and an elevated abundance of genes involved in bacterial growth and division. These changes were similar to trends observed in the obese human gut microbiome, where overfeeding of the microbiome creates a dysbiosis detrimental to the long-term health of the metazoan host. Together these results show that there are specific biogeochemical changes at coral–turf algal interfaces that predict the competitive outcomes between holobionts and are consistent with algal exudates feeding coral-associated microbes.
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Wenderoth, Heinz. "Phycoerythrin: Release from Cryptophycean Algae and Bilin Storage by the Primitive Metazoon Trichoplax adhaerens (Placozoa)." Zeitschrift für Naturforschung C 49, no. 7-8 (August 1, 1994): 458–63. http://dx.doi.org/10.1515/znc-1994-7-811.
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Animal species that store bilins from external sources are very rare. A new example is described here. - Since the primitive marine metazoon Trichoplax adhaerens stains crimsonred when feeding on a phycoerythrin-containing alga. i.e. Pyrenomonas sp. (Cryptophyceae), the question arose whether an algal pigment can be identified as the staining matter. Thin layer chromatography and visible light absorption spectrography of aqueous Trichoplax extract disclosed several bilin components representing chromophores of phycoerythrin, a photosynthetic antenna protein that occurs only in certain algae and cyanobacteria. - Additional experiments showed that a cell-free Trichoplax extract kills and incompletely digests Pyrenomonas algae releasing phycoerythrin into the medium. These digestive faculties of Trichoplax tissue components, probably enzymes, contribute to the animal’s natural feeding mechanisms that proceed extra-as well as intracorporally. While the large apoprotein component of phycoerythrin is metabolized as a nutrient, the remaining chromophore bilins, strikingly coloured tetrapyrroles, are stored within Trichoplax’ distinct cellular inclusions, staining the animal crimson
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Hong, Jiarong, Siddharth Talapatra, Joseph Katz, Patricia A. Tester, Rebecca J. Waggett, and Allen R. Place. "Algal Toxins Alter Copepod Feeding Behavior." PLoS ONE 7, no. 5 (May 18, 2012): e36845. http://dx.doi.org/10.1371/journal.pone.0036845.
Full textDissertations / Theses on the topic "Algal feeding"
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Richardson-Coy, Robin. "Feeding Selectivity of an Algivore (Tropheus brichardi) in Lake Tanganyika." Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright1492509389713611.
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Gatenby, Catherine M. "A study of holding conditions, feed ration, and algal foods for the captive care of freshwater mussels." Diss., This resource online, 2000. http://scholar.lib.vt.edu/theses/available/etd-02132009-171006/.
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Radley, Reed Alan. "The effect of foliar applications of sprays made from kelp (macrocystis integrifolia) on growth of phaseolus vulgaris : b possible role of algal phytohormone-like substances." Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/29773.
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The effects of two applications of foliar sprays made from kelp (Macrocystis intearifolia Bory) on growth of beans (Phaseolus vulgaris L.) under three moisture regimes were investigated. Date of kelp harvest had little effect on plants grown in water excess or deficit conditions, although means for kelp collected in spring tended to be higher. On soils maintained near field capacity, spray made from kelp collected in July resulted in increases in some bean yield components beyond the effects of kelp collected in spring or fall. The effect of storage of liquefied kelp at room temperature was also investigated and found to be soil moisture dependent. Leaf and root weights of plants grown in field capacity and dry soil respectively were lower for plants treated with kelp aged for 118 days compared to plants treated with kelp stored for longer or shorter durations. In wet soil conditions, the effect of sprays on plant height was reduced by storage of the liquefied kelp. Kelp extracts were fractionated by solvent partition. The butanolic fraction was shown to increase significantly many yield variables under wet soil conditions. This fraction had cytokinin-like activity in two bioassay systems, and contained substances co-eluting with isopentenyl adenine and zeatin in column, thin layer, and gas-liquid chromatography systems. Non-significant increases for some plant yield components resulting from application of unfractionated kelp paralleled these increases. A kelp fraction with undefined constituents increased some yield variables of plants grown in field capacity soil, as did a fraction with auxin and gibberellin-like activities in bioassay. The presence of inhibitors in the kelp was indicated by significantly lower pod yields under dry soil conditions, and a reduction in cytokinin-like bioassay activity when increasing amounts of kelp were assayed. The possibility that phytohormone deficits resulting from root stress are ameliorated by some components of the kelp spray is discussed.Land and Food Systems, Faculty of
Graduate
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Wareham, M. T. "The feeding of Nais elinguis (Muller) on algae." Thesis, Cardiff University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354748.
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Somers, Rosemarie. "The Effects of Feeding Seaweed Extract in the Diet of Swine on Gut Health, Performance, Carcass Characteristics, and Pork Quality." Thesis, North Dakota State University, 2017. https://hdl.handle.net/10365/28386.
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Consumers are concerned about antibiotic and ractopamine usage; therefore, alternatives need to be found. Objectives of this study were to investigate the effects of using seaweed as an alternative feed supplement and comparing performance, carcass, pork quality, and immune traits in pigs fed seaweed, control, and ractopamine diets. Pigs were allocated to one of three treatments (CON, SWE, RAC) at weaning (n = 40/treatment). Pigs were weighed every two weeks. Carcass characteristics, pork quality, and immune data were collected post-mortem. No differences were found between treatments for feed intake, growth, or feed efficiency. Pigs on RAC treatment had greater hot carcass weight and dressing percentage (P < 0.05). Chops from RAC pigs were lighter (P = 0.05), less red (P < 0.05), and tougher (P = 0.08). There were no differences between treatments for FABP2 gene expression, cell proliferation percentages, or crypt depths. Therefore, no negative effects of feeding seaweed to pigs were found in this study.
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Maart, Brenton Ashley. "The biotechnology of effluent-grown Spirulina, and application in aquaculture nutrition." Thesis, Rhodes University, 1993. http://hdl.handle.net/10962/d1004111.
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The biotechnology of production and utilisation of the cyanobacterium Spirulina has been well documented. Research has centred mainly on application in human and animal nutrition, and has been motivated by the high protein, vitamin, fatty acid and growth factor contents. The main obstacle in realising the full potential of this feed source has been the high production costs associated with its mass culture in defined media. The observation of blooms of Spirulina in tannery effluent evaporation ponds in Wellington, South Africa, prompted this investigation into the harvesting, and nutritional and toxicological evaluation of this potentially low-cost production system, with the ultimate aim of using the product in aquaculture rations. An investigation of the chemical gradient along the evaporation cascade showed a positive correlation between the prevailing chemical conditions and the dominant species populations. A standing crop of 9.5 tonnes/ha of Spirulina was found to be present in the latter alkaline ponds, characterised by relatively lower organic and sulphur contents. Initial harvesting of the biomass was achieved by the design, construction and implementation of a small-scale screen harvest, which yielded a 25 kg (dry weight) crop. A scale-up model was then designed, and implemented in a technical scale harvest, yielding a crop of 250 kg (dry weight). Both these harvests utilised the bloom of surface-autoflocculated biomass. Concentrated cell slurries were sun-dried on muslin beds, and milled to a coarse powder. An evaluation of the harvest revealed a chemical content similar to other published reports of defined media cultures, with the exception of the protein and amino acid contents. The observed lower levels of the latter two are almost certainly due to the sun-drying method employed, known to reduce the protein content due to thermal denaturation. Legislation demands the strict toxicological evaluation of new protein sources, and because of the effluent-nature of the growth medium of this source of Spirulina, its viability lies only in the application as an animal feed or supplement. A range of toxicological tests were chosen that were targeted to elucidate the possible toxicological constraints of this effluentgrown source of protein in animal nutrition. The nucleic acid and pesticide contents of the harvested biomass were within the prescribed safety ranges. Atomic absorption showed minimal accumulation of minerals and heavy metals from the effluent. A bioassay with the brine shrimp Anemia salina showed that the biomass contained no toxicologically active water-soluble components. A short term feeding trial with new-born chicks showed that supplementation with Spirulina had no effect on the growth rates and feed conversion ratios of the different feeding groups. Pathological analyses showed that the liver was the only target organ to elicit a change in response to supplementation of the diets with Spirulina. A general decrease in liver weight was noted, with Cu, Ca, Fe and Zn being significantly accumulated. A histopathological examination however, showed no cellular and functional aberration from the control animals. The toxicological analyses gave the preliminary safe go-ahead for the evaluation of effluent-grown Spirulina in aquaculture nutrition. The South African abalone Haliotis midae, and the rainbow trout Oncorhynchus mykiss were chosen as representative species of edible cultured organisms. The technology for the culture of the perlemoen abalone is being established in South Africa, with the main area of research being the development of an artificial diet for high density culture. A 40 day growth trial demonstrated that lower concentrations of Spirulina supplemented to an agar-based fishmeal diet resulted in growth rates and feed conversion ratios similar to the control fishmeal and purified-casein diets, and thus has application potential in the nutrition of this high-cost marine delicacy. The aquaculture technology of freshwater rainbow trout is already well established. An eight week feeding trial with various concentrations of Spirulina showed that this effluent-grown protein source can partially replace fishmeal in semi-purified diets. Fish fed Spirulina did not exhibit decisive manifestations of toxicity, as determined in a histopathological study. In addition, Spirulina supplementation resulted in enhanced colouration of the skin and flesh, which may have implications in the aesthetic marketing of this sought-after table fish. The primary aim of this preliminary investigation thus concerned the determination of the biotechnological potential of this effluent-source of Spirulina. A technology transfer from the economically unfeasible defined-media culture was implemented. This project is ultimately aimed as a contribution towards the treatment of tannery wastewater, by the removal of contaminants from the effluent in the form of organic biomass.
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Tsanigab, Salomon M. "Evaluating Namibian macrophytic algae as dietary source for South African abalone (Haliotis midae)." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/1657.
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Thesis (Msc Food Sc (Food Science))--University of Stellenbosch, 2009.An 84-day study was conducted to find a suitable diet and feeding level for the culture of South African abalone (Haliotis midae) in Namibia. Two experimental diets, namely, a seaweed diet (SWD) Laminaria pallida (macrophytic algae) and a formulated diet (FD) (macro-algae), for use in abalone (Haliotis midae) feed development, were evaluated. The animals used in this study were juveniles (24.33 ± 3.14 mm shell length; 2.72 ± 0.83 g live weight, mean ± SE) and sub-adults (58.07 ± 10.33 mm shell length and 41.96 ± 20.61 g live weight, mean ± SE). The nutrient profile of the SWD and FD displayed no differences in the protein and carbohydrate levels. Crude protein levels ranged from 4.91 to 17.68% (dry matter (DM) basis). The lipid levels in the FD (0.25%) were almost 0.56% lower than that in the SWD (0.76%). The feed conversion ratio (FCR) and protein efficiency ratio (PER) for the sub-adult abalone ranged from 2.80 to 10.90 and 0.10 to 0.40, respectively. The juvenile abalone fed on the FD yielded significantly lower (P < 0.05) FCRs (0.8) and higher PERs (1.20) than their counterparts fed on the SWD. A similar trend was observed for the sub-adult abalone although the differences were not significant (P > 0.05). The relative growth rate (RGR) of juvenile fed on the FD was 25% lower compared to those fed on the SWD, while that of the sub-adult abalone fed on the FD was 29% lower compared to the abalone fed on the SWD. From the daily growth rate (DGR) in terms of daily body weight (DGRBW) calculated after the 84-day period, repeated-measures ANOVA (RANOVA) indicated no interaction between time period and diet. Although slightly lower, the DGRBW for the juvenile abalone fed on the SWD diet (0.033 g/day) did not differ significantly from the DGRBW of abalone fed on the FD (0.079 g/day). In contrast, sub-adult abalone fed on the SWD exhibited significantly higher DGRBW compared to those fed on the FD. Although the abalone fed on the FD was slightly higher in nutritional content, there was no significantly difference (P > 0.05) in the nutritional profile of the abalone soft body tissue fed on either the SWD or FD. There was no significant (P > 0.05) difference in preference when comparing the aroma of the abalone meat samples fed on either the SWD or FD. However, there was a significant difference (P < 0.05) in the consumers’ preference in terms of flavour for the abalone sample fed on the FD. The trained taste panel results indicated that there was no difference in the aroma and flavour of the abalone fed on the different diets (P > 0.05). This study showed that cultured juvenile H. midae, readily accepted a FD, producing high consumption and survival rates. The FD still warrants further refinement and testing for it to become a more effective mariculture feed with commercial potential.
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Potts, Warren Mason. "A nutritional evaluation of effluent grown algae and zooplakton as feed ingredients for Xiphohorous helleri, Poecilia reticulata and Poecilia velifera (Pisces : Poeciliidae)." Thesis, Rhodes University, 1998. http://hdl.handle.net/10962/d1005151.
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The aim of this study was to evaluate the nutritional value of algae and zooplankton grown in an algal integrated ponding system for poeciliids. The available information on the nutritional requirements of poeciliids was compared with a proximate analysis of the algae and zooplankton. The effluent grown algae and zooplankton had a crude protein value of 41.47 ± 0.2% and 36.84 ± 0.3%, a lipid content of 4.8 ±. 0.4% and 11.1 ± 0.8% and a carbohydrate content of 35.13 ± 0.8% and 31.06 ± 0.6% respectively. These values compared favourably with those of the known nutritional requirements of poeciliids. To test if the nutritional value of the algae and zooplankton in the AlPS was constant, the species composition of the algae and the crude protein content of the algae and zooplankton in the high rate oxidation ponds were measured monthly and bi-weekly for a year respectively. The species composition remained fairly stable for the duration of the experiment and the average protein composition of the algae and zooplankton was 43.4 ± 4.4% and 38.6 ±2.8% respectively. This indicated that the algae and zooplankton in the AlPS provided high protein biomass through the year. The quality of the effluent grown algal and zooplankton biomass was evaluated by analysing their amino acid composition and comparing it with the amino acid composition of the body tissue of X. helleri. With respect to the amino acid composition of the body tissue of X. helleri, the amino acid profile of the algae had a 69% and the zooplankton a 63% similarity. The quality of the pure algal and zooplankton protein was also tested biologically, by feeding them directly to poeciliids during a ten week growth trial. The algae and zooplankton diets did not result in adequate growth compared to poeciliids which were fed a formulated control diet. The initial growth trial also evaluated the effect of processing on the chemical composition of the algae and its biological effect on fish fed with it. There were no significant differences in the chemical composition of fresh and sun dried algae and this was reflected in the growth rates of the fish which did not differ significantly. Freeze dried algae had a lower crude protein content than fresh and sun dried algae and a poorer amino acid composition. Fish fed freeze dried algae exhibited poorer growth and survival in comparison to the other treatments. The gut transit times of X. helleri and the gastric evacuation times of poeciliids were determined using colour dyes incorporated in the diet and by sacrificing fish at predetermined intervals after feeding respectively. The gut transit time of X. helleri fed a sun dried algal diet and a formulated diet was 225 ± 8.55 minutes and 261.93 ± 10.86 minutes respectively. The gastric evacuation times of X. helleri, P. reticu/ata and P. velifera were 7, 9 and 8 hours respectively. Since the maximum amount of food in the hindgut after feeding was detemined to be 3, 5 and 3 hours in X. helleri, P. reticulata and P. velifera respectively, fish were sacrificed at these times in the digestibility study. The digestibility of sun dried algae was determined using 1 % chromic oxide as an internal marker in the algae. The apparent crude protein digestibility of sun dried effluent grown algae ranged from 65%-75% in the three poeciliid species. Based on the results of the chemical and biological analysis of the algae and zooplankton, conventional diets incorporating algae at 5% and 20% protein inclusion levels were formulated. These diets and a treatment in which zooplankton, reared in the AlPS were fed as a dietary supplement to a formulated diet were fed to poeciliids for twelve weeks. No significant differences in the growth of poeciliids fed any of the test diets were observed. It was concluded that the algae could be incorporated into poeciliid formulated diets up to level of 20% protein inclusion without any negative effect on the growth of the fish. The chemical and biological evaluation of the algae suggested that it had a similar nutritional quality to soyabean meal. Poeciliid growth was not enhanced with a zooplankton supplement, however a possible low feeding rate by poeciliids on the zooplankton as a result of their small size may have affected the result. The colour enhancement potential of effluent grown algae and zooplankton was evaluated biologically in ten and twelve week growth trials using visual observation (31 people) and by using a chromameter. While pure, sun dried algae significantly enhanced the colour of P. reticulata, no significant differences in the colour of poeciliids were observed or recorded when fish were fed diets incorporating sun dried algae up to levels of 20% protein inclusion. The effect of effluent grown algae and zooplankton on poeciliid health was also tested biologically in the ten and twelve week growth trials. The high mortalities (75%-84%) recorded for X. hel/eri when fed the pure algal and zooplankton diets were considered to be as a result of the nutritional inadequacy of the diets since there were significantly less mortalities in fish fed the formulated control diet and 63% of the fish that died during the course of the trial were emaciated. In addition, fewer mortalities (10%-40%) were recorded in X. hel/eri fed the nutritionally adequate formulated diets in the twelve week growth trial. No symptoms of disease were recorded in the twelve week growth trial and the algae was considered to have no toxicological or pathological effects on poeciliids. Centrifugation, sand filtration, sedimentation, microstraining and biological harvest were evaluated as methods of small scale algal harvest from the high rate oxidation ponds. Algae could be harvested most efficiently with little associated labour by sedimentation (without flocculating agents) and by microstraining with 60IJm mesh. Effluent grown algae can replace conventional feed ingredients up to a level of 20% protein inclusion without negatively effecting the growth, colour, health or survival of poeciliids.
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Piltz, Sofia Helena. "Models for adaptive feeding and population dynamics in plankton." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:811fd94d-d58e-48fa-8848-ad7dc37a099f.
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Traditionally, differential-equation models for population dynamics have considered organisms as "fixed" entities in terms of their behaviour and characteristics. However, there have been many observations of adaptivity in organisms, both at the level of behaviour and as an evolutionary change of traits, in response to the environmental conditions. Taking such adaptiveness into account alters the qualitative dynamics of traditional models and is an important factor to be included, for example, when developing reliable model predictions under changing environmental conditions. In this thesis, we consider piecewise-smooth and smooth dynamical systems to represent adaptive change in a 1 predator-2 prey system. First, we derive a novel piecewise-smooth dynamical system for a predator switching between its preferred and alternative prey type in response to prey abundance. We consider a linear ecological trade-off and discover a novel bifurcation as we change the slope of the trade-off. Second, we reformulate the piecewise-smooth system as two novel 1 predator-2 prey smooth dynamical systems. As opposed to the piecewise-smooth system that includes a discontinuity in the vector fields and assumes that a predator switches its feeding strategy instantaneously, we relax this assumption in these systems and consider continuous change in a predator trait. We use plankton as our reference organism because they serve as an important model system. We compare the model simulations with data from Lake Constance on the German-Swiss-Austrian border and suggest possible mechanistic explanations for cycles in plankton concentrations in spring.
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Whittington-Jones, Kevin John. "Ecological interactions on a rocky shore : the control of macroalgal distribution by intertidal grazers." Thesis, Rhodes University, 1998. http://hdl.handle.net/10962/d1005350.
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The aim of the present study was to determine the potential impact of intertidal grazers on the distribution of macro algae on the south coast of South Africa. Particular attention was paid to the large patellid limpet, Patella oculus, which is found thoughout the intertidal zone. Studies of gut contents revealed that Patella oculus was capable of ingesting not only the thallus of foliose (eg. Ulva spp.) and encrusting coralline macroalgae, but also spores and diatoms. The inclusion of these relatively small particles in the diet was surprising, as electron micrographs of the radula of P.oculus revealed that it is typically docoglossan in structure. Such radulae are thought to be poorly suited for collecting small food particles. Sand made up a significantly higher proportion of the gut contents than other particles at all shore heights, which suggests that P.oculus might be capable of excavating the rocky substratum, or of sweeping up sand, while searching for food. Analysis of the gut contents of other local herbivorous molluscs, was also carried out. These species included the winkles, Oxystele variegata and O.sinensis, and the small pulmonate limpets, Siphonaria concinna, S.capensis, and S.serrata. The guts of all species contained mainly spores and diatoms, although small fragments of Ulva sp. were found. The population structure of Patella oculus was investigated at two sites, Cannon Rocks and Old Woman's River. At Cannon Rocks, mean shell length of low-shore animals was significantly lower than that of both mid- and high-shore animals, while at Old Woman's River, no significant difference was found among shore heights. A regression equation for In (shell length) vs In (dry weight) was calculated, and based on length data, the biomass density (g dry mass.m⁻²) of P.oculus at Old Woman's River was estimated. Values ranged from 2.8 on the low- and midshore to 0.37 on the high-shore. A manipulative field experiment was used to determine the impact of mesograzers and macrograzers (such as Patella oculus) on the distribution of intertidal macro algae on the mid- and low-shore at Old Woman's River. Grazers were excluded using mesh cages (mesh size = 3mm), in two separate experiments, one in winter and the other in spring. Percentage cover of macroalgal species and sessile invertebrates was estimated at approximately 6 week intervals for up to 3 months. MANOV A showed that treatments did not significantly affect cover of macroalgae or barnacles during winter. However, towards the end of the spring experiment (midshore only) cover of barnacles and green foliose turfs did increase in those plots from which mesograzers and/or macro grazers were excluded. The failure of the statistical tests to detect significant differences at some time intervals may have been caused by high levels of variation among replicates. This suggests that factors other than grazing are of overriding importance in determining the distribution of local macroalgae. The existence of a possible symbiotic relationship between Patella oculus and the red foliose alga, Gelidium pristoides, was investigated. The availability of various substratum types, including rock, limpet shells, barnacles etc., and the proportion of the total cover of G.pristoides on each, was calculated. It was shown that a significantly higher proportion of the alga grew on limpet shells, although the availability of this substratum type was low. It is thought that the aggressive behaviour of P.oculus prevents all but juvenile Patella longicosta from grazing on its shell, thus providing a refuge from grazing for G.pristoides.
Books on the topic "Algal feeding"
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Alstyne, Kathryn Lyn Van. Feeding preferences for juvenile and adult algae depend on algal stage and herbivore species. [Harstead, Germany]: Inter-Research, 1999.
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Wilkenfeld, Joshua S. Survival, metamorphosis and growth of penaeid shrimp larvae reared on a variety of algal and animal foods. College Station, Tex: Sea Grant College Program, Texas A & M University, 1985.
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Fatherree, Jim. Soft corals: Selecting and maintaining soft corals, feeding and algal symbiosis, lighting and water clarity. Neptune City, NJ: T.F.H. Publications, 2000.
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Hard corals: Selecting and maintaining hard corals, feeding and algal symbiosis, lighting and water clarity. Neptune City, NJ: T.F.H. Publications, 2000.
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Goldstein, Barry. Microalgae production and shellfish feeding trials at the Roswell Test Facility. Las Cruces, N.M: New Mexico Water Resources Research Institute, New Mexico State University, 1990.
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Robinson, Anja M. The effects of dietary algal and lipid supplements on the gonadal and larval development of Crassostrea gigas kumamoto (Thunberg). 1991.
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Fatherree, Jim. Soft Corals: Selecting and Maintaining Soft Corals Feeding and Algal Symbiosis Lighting and Water Clarity (Creating the Reef Environment). TFH Publications, 1998.
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McAlister, Justin S., and Benjamin G. Miner, eds. Phenotypic Plasticity of Feeding Structures in Marine Invertebrate Larvae. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198786962.003.0008.
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Nearly three decades ago, biologists discovered that planktotrophic larvae of sea urchins can alter the size of their ciliated feeding structures in response to the concentration of food (i.e., unicellular algae). In the years since, this response has become one of the best-studied examples of phenotypic plasticity in marine organisms. Researchers have found that this form of plasticity occurs widely among different types of feeding larvae in several phyla, and involves energetic trade-offs with a suite of correlated life history characters. Furthermore, investigators have recently started to unravel the genetic and molecular mechanisms underlying this plasticity. We review the literature on feeding-structure plasticity in marine invertebrate larvae. We highlight the diversity of species and variety of experimental designs and statistical methodologies, summarize research findings to draw more general conclusions, and target promising directions for future research.
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Sheppard, Charles. 5. Microbial and planktonic engines of the reef. Oxford University Press, 2014. http://dx.doi.org/10.1093/actrade/9780199682775.003.0005.
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Symbiotic algae are a crucial source of fuel for the reef, via corals and others, but how is the food and energy from the corals transferred to other parts of the ecosystem to support the huge abundance and diversity seen there? ‘Microbial and planktonic engines of the reef’ describes the filter feeding—extracting particles from the water—of the large proportion of reef animals. These particles consist of plankton, microbes, bacteria, viruses, and zooplankton. Sponges also display microbial symbiotic connections with algae and cyanobacteria that is a key component of material and energy transfer. The productivity from seaweeds on which numerous species of herbivorous fish and sea urchins graze is also important.
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Trowbridge, Cynthia D. Marine herbivore-plant interactions: The feeding ecology of the sea slug Placida dendritica. 1989.
Find full textBook chapters on the topic "Algal feeding"
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Meyer, Achim, Julia Merkel, and Bernhard Lieb. "Collecting and Culturing Kamptozoans for Regenerative Studies." In Methods in Molecular Biology, 135–49. New York, NY: Springer US, 2022. http://dx.doi.org/10.1007/978-1-0716-2172-1_7.
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AbstractKamptozoa, also known as Entoprocta, are small aquatic filter-feeders that belong to the Lophotrochozoan superphylum, which also contains other acoelomate phyla including Annelida, Nemertea, and Mollusca. The study of Kamptozoa is thus of great interest to understand the early Lophotrochozoan evolution. Moreover, many kamptozoans have been shown to possess great regeneration capacities, including whole-body regeneration. In addition, and in particular for colonial cosmopolitan species such as Barentsia benedeni, kamptozoans are highly suitable as laboratory model organisms because of their simple culture, low space requirements, transparency and rapid life cycle. This chapter provides a brief introduction into field collection, culturing techniques for both the animals as well as the algae required for their feeding, fixation, staining, and sequencing.
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Ward, J. Evan, and Nancy M. Targett. "Are Metabolites from the Brown Tide Alga, Aureococcus anophagefferens, Deleterious to Mussel Feeding Behavior?" In Novel Phytoplankton Blooms, 543–56. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-75280-3_30.
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Ward, J. Evan, and Nancy M. Targett. "Are metabolites from the brown tide alga, Aureococcus anophagefferens, deleterious to mussel feeding behavior?" In Coastal and Estuarine Studies, 543–56. Washington, D. C.: American Geophysical Union, 1989. http://dx.doi.org/10.1029/ce035p0543.
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Gallager, Scott M., Diane K. Stoecker, and V. Monica Bricelj. "Effects of the Brown Tide Alga on Growth, Feeding Physiology and Locomotory Behavior of Scallop Larvae (Argopecten irradians)." In Novel Phytoplankton Blooms, 511–41. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-75280-3_29.
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Gallager, Scott M., Diane K. Stoecker, and V. Monica Bricelj. "Effects of the brown tide alga on growth, feeding physiology and locomotory behavior of scallop larvae (Argopecten irradians)." In Coastal and Estuarine Studies, 511–41. Washington, D. C.: American Geophysical Union, 1989. http://dx.doi.org/10.1029/ce035p0511.
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Bontés, Babette M., Antonie M. Verschoor, L. Miguel Dionisio Pires, Ellen van Donk, and Bas W. Ibelings. "Functional response of Anodonta anatina feeding on a green alga and four strains of cyanobacteria, differing in shape, size and toxicity." In Shallow Lakes in a Changing World, 191–204. Dordrecht: Springer Netherlands, 2007. http://dx.doi.org/10.1007/978-1-4020-6399-2_18.
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Sheppard, Charles. "6. Reef fish and other major predators." In Coral Reefs: A Very Short Introduction, 68–84. Oxford University Press, 2021. http://dx.doi.org/10.1093/actrade/9780198869825.003.0006.
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Fish, like corals, have geographical patterns across regions and across individual reefs, being structured in the latter case by wave energy and depth. The thousands of species show a variety of feeding patterns. Detritus feeders are very abundant, feeding on the detritus on the seabed, especially in the fine, filamentous algal turf on apparently bare rock. Plankton feeders are common also, and herbivorous fishes show a large abundance, perhaps a quarter of the total species present, cropping algae that otherwise would grow unchecked and smother coral. Since turf algae also contain many micro-species and detritus, most herbivores also ingest much food other than simple plant material. Carnivores range from extreme specialists, such as polyp-picking butterflyfish, to generalists. Sharks and barracuda only consume other fish and generally are at the top of their food chains. The complicated ecological structure of the food webs can be clarified by analysing nitrogen isotope ratios in their tissues. Other important coral carnivores include the crown of thorns starfish, which can remove almost all living coral on a reef when it develops into plagues. Overfishing by humans greatly disturbs the equilibrium of a reef, and this is increasingly causing reef degradation.
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"Early Life History of Fishes in the San Francisco Estuary and Watershed." In Early Life History of Fishes in the San Francisco Estuary and Watershed, edited by Bradd Baskerville-Bridges, Joan C. Lindberg, and Serge I. Doroshov. American Fisheries Society, 2004. http://dx.doi.org/10.47886/9781888569599.ch14.
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<em>Abstract.</em>—Understanding how environmental factors influence first feeding success is critical for the conservation-oriented larval culture of delta smelt <em>Hypomesus transpacificus</em>, a threatened osmerid endemic to the San Francisco Estuary. We investigated the effects of light intensity, alga concentration, and prey (rotifer) density on feeding of cultured delta smelt larvae. In one experiment, first feeding larvae were exposed to three light intensities (0.01, 0.3, and 1.9 μmoles <sup>. </sup>s<sup>–1. </sup>m<sup>–2</sup>) and three alga concentrations (0, 0.5, and 2 × 10<sup>6 </sup>cells/mL). Intestinal contents were examined to determine the incidence of feeding and gut fillness. Maximum feeding responses (92% feeding; 4.8 rotifers/feeding larva in 2 h) were observed at the highest light intensity and alga concentrations; feeding sharply declined with a reduction of either factor. A second experiment was performed to study the effect of alga concentration (0, 1.5, 3, and 6 × 10<sup>6 </sup>cells/mL) in more detail. Feeding responses were very low without algae (13% feeding; 2.1 rotifers/feeding larva in 2 h), but dramatically increased at high concentrations (83% feeding; 5.1 rotifers/feeding larvae in 2 h). In a third experiment, the effect of prey (rotifer) density (0.1, 1, 10, and 100 rotifers/mL) was tested, which significantly enhanced feeding up to the 10/mL treatment (84% feeding; 4.2 rotifers/feeding larvae in 1 h). All three environmental factors significantly affected feeding success of larval delta smelt. Optimization of these factors has improved survival and growth during the sensitive larval period and has improved laboratory culture of delta smelt.
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Kirchman, David L. "Giving the Land a Kick." In Dead Zones, 72–88. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780197520376.003.0006.
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When it became clear that nutrients cause the rise of dead zones, scientists next examined the possible sources of the nutrients. This chapter argues the biggest source today is agriculture. The expansion of the Gulf of Mexico dead zone directly follows the huge increase in agricultural productivity, especially for corn. Yields increased over six times since 1930 in part because farmers used more fertilizer, “to give the land a kick.” As the chapter explains, Nancy Rabalais and Gene Turner found a direct link between fertilizer use and nutrient levels in the Mississippi River. In spite of opposition from agribusinesses, their work led to the formation of a White House committee and passage of legislation to support work on the hypoxia problem. Agriculture is also the main source of nutrients feeding dead zones in other regions of the world. The chapter later points out that the biggest user of fertilizer is now China, where excessive nutrients have caused massive harmful algal blooms and other environmental problems.
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Johengen, Thomas, Henry Vanderploeg, and James Liebig. "Effects of Algal Composition, Seston Stoichiometry, and Feeding Rate on Zebra Mussel (Dreissena polymorpha) Nutrient Excretion in Two Laurentian Great Lakes." In Quagga and Zebra Mussels, 445–60. CRC Press, 2013. http://dx.doi.org/10.1201/b15437-34.
Full textConference papers on the topic "Algal feeding"
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Aleksandrov, Sergey, Sergey Aleksandrov, Julia Gorbunova, and Julia Gorbunova. "CLIMATE CHANGE: HOW DOES THIS INFLUENCE ON ECOSYSTEM HEALTH IN THE LAGOON OF THE BALTIC SEA?" In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.31519/conferencearticle_5b1b93942cc882.47943475.
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Lagoons are one of the most vulnerable ecosystems to impacts of natural environmental and anthropogenic factors. The Curonian and Vistula Lagoons are one of the largest lagoons of Europe. The Curonian Lagoon is choke mostly freshwater, while the Vistula Lagoon is restricted brackish water. Hydrological, chemical and biological researches were carried out monthly since 1991 to 2014. Reductions of nutrients loading in 1990s did not result in improvement of the ecological situation. Hydrological and chemical parameters are the main factors that influence on the algal blooms and ecosystem health in these lagoons. The Curonian Lagoon may be characterized as hypertrophic water body with "poor" water quality. Climate change in 1990s-2010s combined with other factors (freshwater, slow-flow exchange, high nutrients concentrations) creates conditions for Cyanobacteria “hyperblooms”. Harmful algal blooms result in deterioration of the water chemical parameters and death of fish. "Hyperblooms" is the most dangerous for coastal towns and tourist resorts (UNESCO National Park "Curonian Spit"). Climate change in 1990s-2000s have been also observed in Vistula Lagoons (mean annual temperature increased by 1.4°C for 40 years), but brackish water prevent harmful algal hyperblooms. After the invasion of the filter-feeding mollusk Rangia water quality was significantly improved in 2011-2014, but ecosystem productivity remained at a stable long-term level.
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Aleksandrov, Sergey, Sergey Aleksandrov, Julia Gorbunova, and Julia Gorbunova. "CLIMATE CHANGE: HOW DOES THIS INFLUENCE ON ECOSYSTEM HEALTH IN THE LAGOON OF THE BALTIC SEA?" In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.21610/conferencearticle_58b4316a72251.
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Lagoons are one of the most vulnerable ecosystems to impacts of natural environmental and anthropogenic factors. The Curonian and Vistula Lagoons are one of the largest lagoons of Europe. The Curonian Lagoon is choke mostly freshwater, while the Vistula Lagoon is restricted brackish water. Hydrological, chemical and biological researches were carried out monthly since 1991 to 2014. Reductions of nutrients loading in 1990s did not result in improvement of the ecological situation. Hydrological and chemical parameters are the main factors that influence on the algal blooms and ecosystem health in these lagoons. The Curonian Lagoon may be characterized as hypertrophic water body with "poor" water quality. Climate change in 1990s-2010s combined with other factors (freshwater, slow-flow exchange, high nutrients concentrations) creates conditions for Cyanobacteria “hyperblooms”. Harmful algal blooms result in deterioration of the water chemical parameters and death of fish. "Hyperblooms" is the most dangerous for coastal towns and tourist resorts (UNESCO National Park "Curonian Spit"). Climate change in 1990s-2000s have been also observed in Vistula Lagoons (mean annual temperature increased by 1.4°C for 40 years), but brackish water prevent harmful algal hyperblooms. After the invasion of the filter-feeding mollusk Rangia water quality was significantly improved in 2011-2014, but ecosystem productivity remained at a stable long-term level.
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Marshall, Lauren, Adam Schroeder, and Brian Trease. "Comparing Fish-Inspired Ram Filters for Collection of Harmful Algae." In ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-88797.
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In this work, several different bioinspired filter geometries are proposed, fabricated, and tested in a flow tank. A novel approach is explored that mimics how filter-feeding fish efficiently remove small food particles from water. These filters generally take the form of a cone with water entering the large end of the cone and exiting through mesh-covered slots in the side of the cone, which emulates the rib structure of these filter-feeding fish. The flow in and around the filters is characterized and their ability to collect algae-scale, neutrally-buoyant particles is evaluated. Filter performance is evaluated by using image processing to count the number of particles collected and studying how the particles are deposited on the filter. Results are presented in the form of particle collection efficiencies, which is a ratio of particles collected to the particles that would nominally enter the filter inlet, and images of the fluorescent particles deposited on the filter at different time intervals. The results show little sensitivity to the filters’ inlet geometries, which was the major difference between filters tested. Comparative results are also presented from a 2D CFD model of the filters generated in COMSOL. The different geometries may differentiate themselves more at larger Reynolds numbers, and it is believed that a fluid exit ratio, or ratio of inlet area to exit area, is the most critical filter parameter. Field testing has demonstrated collection of real algae (i) with this bioinspired filter, and (ii) from a robot platform, but using a more conventional plankton net. The larger vision is to develop these filters and mount them on a swarm of autonomous surface vehicles, i.e. a robot boat swarm, which is being developed in parallel.
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Bazinet, Richard. "New methods using natural abundance carbon isotope ratio analysis to measure the turnover of docosahexaenoic acid in preclinical models." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/aloq1878.
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Recently, our laboratory has explored an alternative and cost-effective technique called compound-specific isotope analysis by gas-chromatography isotope ratio mass spectrometry that takes advantage of natural differences in carbon-13 content (13C/12C ratio or d13C) of the food supply to better understand tissue DHA metabolism. However, a lack of variation in the d13C of some molecules limits the methods utility. Here I will present two novel approaches that can be used to circumvent this limitation. Alpha-linolenic acid (ALA), is a well know precursor to docosahexaenoic acid, but it is difficult to find ALA from sources with different d13C. In the first study we fed mice DHA sourced from algae (enriched in carbon 13) chronically and then switched the mice to less enriched fatty acid sources including ALA from flaxseed oil, ALA and stearidonic acid (SDA) from ahiflower oil or DHA derived from fish oil. We show that DHA tissue turnover can be measured from dietary ALA, ALA and SDA or DHA. In the second study upon chronically feeding mice DHA obtained from fish oil we switched mice to a diet either spiked with a small amount (~0.03%) of uniformly labeled DHA to increase the d13C of DHA or to DHA derived from algae. Not only could we differentiate the sources of DHA in the tissues, but the different sources of DHA produced similar tissue half lives. In conclusion, limitations in the natural variance of d13C can be circumvented by changing the d13C content of metabolic products or by adding small amounts of labelled molecules to increase the d13C content.
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Ma, Yiwei, and Chi Chen. "Metabolomic analysis revealed dose-dependent effects of algae feeding on redox balance, lipid, and microbial metabolism in mouse." In The 2nd International Electronic Conference on Metabolomics. Basel, Switzerland: MDPI, 2017. http://dx.doi.org/10.3390/iecm-2-04985.
Full textReports on the topic "Algal feeding"
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Mitchell, Brian G., Amir Neori, Charles Yarish, D. Allen Davis, Tzachi Samocha, and Lior Guttman. The use of aquaculture effluents in spray culture for the production of high protein macroalgae for shrimp aqua-feeds. United States Department of Agriculture, January 2013. http://dx.doi.org/10.32747/2013.7597934.bard.
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The FAO has projected a doubling in world demand for seafood during the 21 ed from aquaculture of marine fish and shrimps fed primarily on fishmeal-based aquafeeds. However, current practices of high intensity monoculture of shrimp in coastal ponds and fish in offshore pens have been strongly criticized as being ecologically and socially unsustainable. This view derives from un- checked eutrophication of coastal marine ecosystems from fish farm effluents, and the destruction of coastal estuarine ecosystems by shrimp farm constructions, plus aquaculture’s reliance on wild-caught small fish - which are excellent food for humans, but instead are rendered into fishmeal and fish oil for formulating aquafeeds. Fishmeal-sparing and waste- reduction aquafeeds can only delay the time when fed aquaculture product are priced out of affordability for most consumers. Additionally, replacement of fishmeal protein and fish oil by terrestrial plant sources such as soybean meal and oil directly raises food costs for human communities in developing nations. New formulations incorporating sustainably-produced marine algal proteins and oils are growing in acceptance as viable and practical alternatives. This BARD collaborative research project investigated a sustainable water-sparing spray/drip culture method for producing high-protein marine macrophyte meals for incorporation into marine shrimp and fish diets. The spray culture work was conducted at laboratory-scale in the USA (UCSD-SIO) using selected Gracilariaand Ulvastrains isolated and supplied by UCONN, and outdoors at pilot-scale in Israel (IOLR-NCM) using local strains of Ulvasp., and nitrogen/phosphorus-enriched fish farm effluent to fertilize the spray cultures and produce seaweed biomass and meals containing up to 27% raw protein (dry weight content). Auburn University (USA) in consultation with TAMUS (USA) used the IOLR meals to formulate diets and conduct marine shrimp feeding trials, which resulted in mixed outcomes, indicating further work was needed to chemically identify and remove anti-nutritional elements present in the IOLR-produced seaweed meals.