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Jose Luis Acuna - One of the best experts on this subject based on the ideXlab platform.
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Body size‐based Trophic Structure of a deep marine ecosystem
Ecology, 2016Co-Authors: Sonia Romero-romero, Juan Hofer, Axayacatl Molina-ramírez, Jose Luis AcunaAbstract:Nitrogen stable isotope ratios (δ15N) and body size were used to describe the size-based Trophic Structure of a deep-sea ecosystem, the Aviles submarine Canyon (Cantabrian Sea, Southern Bay of Biscay). We analyzed δ15N of specimens collected on a seasonal basis (March 2012, October 2012, and May 2013), from a variety of zones (benthic, pelagic), taxa (from zooplankton through invertebrates and fishes to giant squids and cetaceans), or depths (from surface to 4700 m) that spanned nine orders of magnitude in body mass. Our data reveal a strong linear dependence of Trophic level on body size when data were considered either individually, aggregated into taxonomical categories, or binned into size classes. The three approaches render similar results that were not significantly different and yielded predator:prey body mass ratios (PPMR) of 1156:1, 3792:1 and 2718:1, respectively. Thus, our data represent unequivocal evidence of interspecific, size-based Trophic Structure of a whole ecosystem based on taxonomic/functional categories. We studied the variability in δ15N not explained by body mass (W) using linear mixed modeling and found that the δ15N vs. log10 W relationship holds for both pelagic and benthic systems, with benthic organisms isotopically enriched relative to pelagic organisms of the same size. However there is a marked seasonal variation potentially related to the recycling state of the system.
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body size based Trophic Structure of a deep marine ecosystem
Ecology, 2016Co-Authors: Sonia Romeroromero, Axayacatl Molinaramirez, Juan Hofer, Jose Luis AcunaAbstract:Nitrogen stable isotope ratios (δ15N) and body size were used to describe the size-based Trophic Structure of a deep-sea ecosystem, the Aviles submarine Canyon (Cantabrian Sea, Southern Bay of Biscay). We analyzed δ15N of specimens collected on a seasonal basis (March 2012, October 2012, and May 2013), from a variety of zones (benthic, pelagic), taxa (from zooplankton through invertebrates and fishes to giant squids and cetaceans), or depths (from surface to 4700 m) that spanned nine orders of magnitude in body mass. Our data reveal a strong linear dependence of Trophic level on body size when data were considered either individually, aggregated into taxonomical categories, or binned into size classes. The three approaches render similar results that were not significantly different and yielded predator:prey body mass ratios (PPMR) of 1156:1, 3792:1 and 2718:1, respectively. Thus, our data represent unequivocal evidence of interspecific, size-based Trophic Structure of a whole ecosystem based on taxonomic/functional categories. We studied the variability in δ15N not explained by body mass (W) using linear mixed modeling and found that the δ15N vs. log10 W relationship holds for both pelagic and benthic systems, with benthic organisms isotopically enriched relative to pelagic organisms of the same size. However there is a marked seasonal variation potentially related to the recycling state of the system.
Erik Jeppesen - One of the best experts on this subject based on the ideXlab platform.
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responses of Trophic Structure and zooplankton community to salinity and temperature in tibetan lakes implication for the effect of climate warming
Water Research, 2017Co-Authors: Lei Xu, Erik JeppesenAbstract:Abstract Warming has pronounced effects on lake ecosystems, either directly by increased temperatures or indirectly by a change in salinity. We investigated the current status of zooplankton communities and Trophic Structure in 45 Tibetan lakes along a 2300 m altitude and a 76 g/l salinity gradient. Freshwater to hyposaline lakes mainly had three Trophic levels: phytoplankton, small zooplankton and fish/Gammarus, while mesosaline to hypersaline lakes only had two: phytoplankton and large zooplankton. Zooplankton species richness declined significantly with salinity, but did not relate with temperature. Furthermore, the decline in species richness with salinity in lakes with two Trophic levels was much less abrupt than in lakes with three Trophic levels. The structural variation of the zooplankton community depended on the length of the food chain, and was significantly explained by salinity as the critical environmental variable. The zooplankton community shifted from dominance of copepods and small cladoceran species in the lakes with low salinity and three Trophic levels to large saline filter-feeding phyllopod species in those lakes with high salinity and two Trophic levels. The zooplankton to phytoplankton biomass ratio was positively related with temperature in two-Trophic-level systems and vice versa in three-Trophic-level systems. As the Tibetan Plateau is warming about three times faster than the global average, our results imply that warming could have a considerable impact on the Structure and function of Tibetan lake ecosystems, either via indirect effects of salinization/desalinization on species richness, composition and Trophic Structure or through direct effects of water temperature on Trophic interactions.
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species richness of crustacean zooplankton and Trophic Structure of brackish lagoons in contrasting climate zones north temperate denmark and mediterranean catalonia spain
Ecography, 2009Co-Authors: Sandra Brucet, Dani Boix, Stephanie Gascon, Jordi Sala, Xavier D Quintana, Anna Badosa, Martin Sondergaard, Torben L Lauridsen, Erik JeppesenAbstract:We sought to identify environmental factors influencing crustacean zooplankton species richness in brackish lagoons and to elucidate whether crustacean zooplankton species richness and Trophic Structure of brackish lagoons differ among two regions with contrasting temperatures. We sampled 35 and 42 brackish lagoons (salinity ranging from 0.3 to 55‰) in Mediterranean Catalonia (NE Spain) and northern-temperate Denmark, respectively. No significant differences were found in total crustacean zooplankton species richness or cladoceran richness between the climatic regions. Calanoid richness was higher in Denmark than in Catalonia, while cyclopoid richness was higher in Catalonia. Salinity was the most important variable associated with zooplankton species richness in both regions, richness of total zooplankton species, cladocerans and cyclopoids being negatively related with salinity. In both regions, a shift occurred from dominance of large filter feeding cladoceran species at low salinities to copepods and small cladoceran species at higher salinities. Cladoceran richness increased with increasing total phosphorus, but was not influenced by total nitrogen or chlorophyll-a. Trophic Structure in Mediterranean brackish lagoons showed a more pronounced seasonal variation than in north temperate brackish lagoons. Our results imply that the indirect effects of climate warming, such as changes in salinity and hydrology, will have a larger impact on brackish lagoon ecosystems than the increase in temperature per se.
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Trophic Structure species richness and biodiversity in danish lakes changes along a phosphorus gradient
Freshwater Biology, 2000Co-Authors: Erik Jeppesen, Martin Sondergaard, Torben L Lauridsen, Jens Peder Jensen, Frank LandkildehusAbstract:1. Using data from 71, mainly shallow (an average mean depth of 3 m), Danish lakes with contrasting total phosphorus concentrations (summer mean 0.02–1.0 mg P L−l), we describe how species richness, biodiversity and Trophic Structure change along a total phosphorus (TP) gradient divided into five TP classes (class 1–5: 0.4 mg P L−1). 2. With increasing TP, a significant decline was observed in the species richness of zooplankton and submerged macrophytes, while for fish, phytoplankton and floating-leaved macrophytes, species richness was unimodally related to TP, all peaking at 0.1–0.4 mg P L−1. The Shannon–Wiener and the Hurlbert probability of inter-specific encounter (PIE) diversity indices showed significant unimodal relationships to TP for zooplankton, phytoplankton and fish. Mean depth also contributed positively to the relationship for rotifers, phytoplankton and fish. 3. At low nutrient concentrations, piscivorous fish (particularly perch, Perca fluviatilis) were abundant and the biomass ratio of piscivores to plankti-benthivorous cyprinids was high and the density of cyprinids low. Concurrently, the zooplankton was dominated by large-bodied forms and the biomass ratio of zooplankton to phytoplankton and the calculated grazing pressure on phytoplankton were high. Phytoplankton biomass was low and submerged macrophyte abundance high. 4. With increasing TP, a major shift occurred in Trophic Structure. Catches of cyprinids in multiple mesh size gill nets increased 10-fold from class 1 to class 5 and the weight ratio of piscivores to planktivores decreased from 0.6 in class 1 to 0.10–0.15 in classes 3–5. In addition, the mean body weight of dominant cyprinids (roach, Rutilus rutilus, and bream, Abramis brama) decreased two–threefold. Simultaneously, small cladocerans gradually became more important, and among copepods, a shift occurred from calanoid to cyclopoids. Mean body weight of cladocerans decreased from 5.1 μg in class 1 to 1.5 μg in class 5, and the biomass ratio of zooplankton to phytoplankton from 0.46 in class 1 to 0.08–0.15 in classes 3–5. Conversely, phytoplankton biomass and chlorophyll a increased 15-fold from class 1 to 5 and submerged macrophytes disappeared from most lakes. 5. The suggestion that fish have a significant structuring role in euTrophic lakes is supported by data from three lakes in which major changes in the abundance of planktivorous fish occurred following fish kill or fish manipulation. In these lakes, studied for 8 years, a reduction in planktivores resulted in a major increase in cladoceran mean size and in the biomass ratio of zooplankton to phytoplankton, while chlorophyll a declined substantially. In comparison, no significant changes were observed in 33 ‘control’ lakes studied during the same period.
Sonia Romeroromero - One of the best experts on this subject based on the ideXlab platform.
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body size based Trophic Structure of a deep marine ecosystem
Ecology, 2016Co-Authors: Sonia Romeroromero, Axayacatl Molinaramirez, Juan Hofer, Jose Luis AcunaAbstract:Nitrogen stable isotope ratios (δ15N) and body size were used to describe the size-based Trophic Structure of a deep-sea ecosystem, the Aviles submarine Canyon (Cantabrian Sea, Southern Bay of Biscay). We analyzed δ15N of specimens collected on a seasonal basis (March 2012, October 2012, and May 2013), from a variety of zones (benthic, pelagic), taxa (from zooplankton through invertebrates and fishes to giant squids and cetaceans), or depths (from surface to 4700 m) that spanned nine orders of magnitude in body mass. Our data reveal a strong linear dependence of Trophic level on body size when data were considered either individually, aggregated into taxonomical categories, or binned into size classes. The three approaches render similar results that were not significantly different and yielded predator:prey body mass ratios (PPMR) of 1156:1, 3792:1 and 2718:1, respectively. Thus, our data represent unequivocal evidence of interspecific, size-based Trophic Structure of a whole ecosystem based on taxonomic/functional categories. We studied the variability in δ15N not explained by body mass (W) using linear mixed modeling and found that the δ15N vs. log10 W relationship holds for both pelagic and benthic systems, with benthic organisms isotopically enriched relative to pelagic organisms of the same size. However there is a marked seasonal variation potentially related to the recycling state of the system.
Linda D Rhodes - One of the best experts on this subject based on the ideXlab platform.
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stable isotope based Trophic Structure of pelagic fish and jellyfish across natural and anthropogenic landscape gradients in a fjord estuary
Ecology and Evolution, 2016Co-Authors: Sean M Naman, Correigh M Greene, Casimir A Rice, Joshua Chamberlin, Letitia L Conwaycranos, Jeffery R Cordell, Jason E Hall, Linda D RhodesAbstract:: Identifying causes of structural ecosystem shifts often requires understanding Trophic Structure, an important determinant of energy flow in ecological communities. In coastal pelagic ecosystems worldwide, increasing jellyfish (Cnidaria and Ctenophora) at the expense of small fish has been linked to anthropogenic alteration of basal Trophic pathways. However, this hypothesis remains untested in part because baseline description of fish-jellyfish Trophic dynamics, and the environmental features that influence them are lacking. Using stable isotopes of carbon (δ13C) and nitrogen (δ15N), we examined spatiotemporal patterns of fish and jellyfish Trophic Structure in greater Puget Sound, an urbanizing fjord estuary in the NW United States. We quantified niche positions of constituent species, niche widths and Trophic overlap between fish and jellyfish assemblages, and several community-level Trophic diversity metrics (resource diversity, Trophic length, and niche widths) of fish and jellyfish combined. We then related assemblage- and community-level measures to landscape gradients of terrestrial-marine connectivity and anthropogenic influence in adjacent catchments. Relative niche positions among species varied considerably and displayed no clear pattern except that fish generally had higher δ15N and lower δ13C relative to jellyfish, which resulted in low assemblage-level Trophic overlap. Fish assemblages had larger niche widths than jellyfish in most cases and, along with whole community Trophic diversity, exhibited contrasting seasonal patterns across oceanographic basins, which was positively correlated to landscape variation in terrestrial connectivity. In contrast, jellyfish niche widths were unrelated to terrestrial connectivity, but weakly negatively correlated to urban land use in adjacent catchments. Our results indicate that fish-jellyfish Trophic Structure is highly heterogeneous and that disparate processes may underlie the Trophic ecology of these taxa; consequently, they may respond divergently to environmental change. In addition, spatiotemporal variation in ecosystem connectivity, in this case through freshwater influence, may influence Trophic Structure across heterogeneous landscapes.
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Stable isotope‐based Trophic Structure of pelagic fish and jellyfish across natural and anthropogenic landscape gradients in a fjord estuary
Ecology and Evolution, 2016Co-Authors: Sean M Naman, Correigh M Greene, Casimir A Rice, Joshua Chamberlin, Jeffery R Cordell, Jason E Hall, Letitia L. Conway-cranos, Linda D RhodesAbstract:Identifying causes of structural ecosystem shifts often requires understanding Trophic Structure, an important determinant of energy flow in ecological communities. In coastal pelagic ecosystems worldwide, increasing jellyfish (Cnidaria and Ctenophora) at the expense of small fish has been linked to anthropogenic alteration of basal Trophic pathways. However, this hypothesis remains untested in part because baseline description of fish–jellyfish Trophic dynamics, and the environmental features that influence them are lacking. Using stable isotopes of carbon (δ13C) and nitrogen (δ15N), we examined spatiotemporal patterns of fish and jellyfish Trophic Structure in greater Puget Sound, an urbanizing fjord estuary in the NW United States. We quantified niche positions of constituent species, niche widths and Trophic overlap between fish and jellyfish assemblages, and several community-level Trophic diversity metrics (resource diversity, Trophic length, and niche widths) of fish and jellyfish combined. We then related assemblage- and community-level measures to landscape gradients of terrestrial–marine connectivity and anthropogenic influence in adjacent catchments. Relative niche positions among species varied considerably and displayed no clear pattern except that fish generally had higher δ15N and lower δ13C relative to jellyfish, which resulted in low assemblage-level Trophic overlap. Fish assemblages had larger niche widths than jellyfish in most cases and, along with whole community Trophic diversity, exhibited contrasting seasonal patterns across oceanographic basins, which was positively correlated to landscape variation in terrestrial connectivity. In contrast, jellyfish niche widths were unrelated to terrestrial connectivity, but weakly negatively correlated to urban land use in adjacent catchments. Our results indicate that fish–jellyfish Trophic Structure is highly heterogeneous and that disparate processes may underlie the Trophic ecology of these taxa; consequently, they may respond divergently to environmental change. In addition, spatiotemporal variation in ecosystem connectivity, in this case through freshwater influence, may influence Trophic Structure across heterogeneous landscapes.
Juan Hofer - One of the best experts on this subject based on the ideXlab platform.
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Body size‐based Trophic Structure of a deep marine ecosystem
Ecology, 2016Co-Authors: Sonia Romero-romero, Juan Hofer, Axayacatl Molina-ramírez, Jose Luis AcunaAbstract:Nitrogen stable isotope ratios (δ15N) and body size were used to describe the size-based Trophic Structure of a deep-sea ecosystem, the Aviles submarine Canyon (Cantabrian Sea, Southern Bay of Biscay). We analyzed δ15N of specimens collected on a seasonal basis (March 2012, October 2012, and May 2013), from a variety of zones (benthic, pelagic), taxa (from zooplankton through invertebrates and fishes to giant squids and cetaceans), or depths (from surface to 4700 m) that spanned nine orders of magnitude in body mass. Our data reveal a strong linear dependence of Trophic level on body size when data were considered either individually, aggregated into taxonomical categories, or binned into size classes. The three approaches render similar results that were not significantly different and yielded predator:prey body mass ratios (PPMR) of 1156:1, 3792:1 and 2718:1, respectively. Thus, our data represent unequivocal evidence of interspecific, size-based Trophic Structure of a whole ecosystem based on taxonomic/functional categories. We studied the variability in δ15N not explained by body mass (W) using linear mixed modeling and found that the δ15N vs. log10 W relationship holds for both pelagic and benthic systems, with benthic organisms isotopically enriched relative to pelagic organisms of the same size. However there is a marked seasonal variation potentially related to the recycling state of the system.
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body size based Trophic Structure of a deep marine ecosystem
Ecology, 2016Co-Authors: Sonia Romeroromero, Axayacatl Molinaramirez, Juan Hofer, Jose Luis AcunaAbstract:Nitrogen stable isotope ratios (δ15N) and body size were used to describe the size-based Trophic Structure of a deep-sea ecosystem, the Aviles submarine Canyon (Cantabrian Sea, Southern Bay of Biscay). We analyzed δ15N of specimens collected on a seasonal basis (March 2012, October 2012, and May 2013), from a variety of zones (benthic, pelagic), taxa (from zooplankton through invertebrates and fishes to giant squids and cetaceans), or depths (from surface to 4700 m) that spanned nine orders of magnitude in body mass. Our data reveal a strong linear dependence of Trophic level on body size when data were considered either individually, aggregated into taxonomical categories, or binned into size classes. The three approaches render similar results that were not significantly different and yielded predator:prey body mass ratios (PPMR) of 1156:1, 3792:1 and 2718:1, respectively. Thus, our data represent unequivocal evidence of interspecific, size-based Trophic Structure of a whole ecosystem based on taxonomic/functional categories. We studied the variability in δ15N not explained by body mass (W) using linear mixed modeling and found that the δ15N vs. log10 W relationship holds for both pelagic and benthic systems, with benthic organisms isotopically enriched relative to pelagic organisms of the same size. However there is a marked seasonal variation potentially related to the recycling state of the system.
