Zoobenthos are minor dietary components of small omnivorous fishes in a shallow eutrophic lake

2016 ◽  
Vol 67 (10) ◽  
pp. 1562 ◽  
Author(s):  
Natsuru Yasuno ◽  
Yuki Chiba ◽  
Yasufumi Fujimoto ◽  
Kentaro Shindo ◽  
Tetsuo Shimada ◽  
...  
Keyword(s):  
Isotope Analysis ◽  
Fish Tissue ◽  
Eutrophic Lake ◽  
Food Sources ◽  
Epiphytic Algae ◽  
Δ13c And Δ15n ◽  
Chironomid Larvae ◽  
Dietary Components ◽  
Shallow Eutrophic Lake ◽  
Potential Food

We examined whether small omnivorous fishes (smaller than ~100mm long) integrate littoral, pelagic and benthic pathways in a shallow, eutrophic lake (Lake Izunuma, Japan). The surface of the lake was covered by a dense vegetation of floating-leaved macrophytes, and small species dominated the icthyofauna. We determined the δ13C and δ15N ratios of five dominant species of small omnivorous fishes. Using a stable isotope analysis in the R mixing model, we determined the possible contribution of three potential food sources (epiphytic algae, zooplankton and zoobenthos (larval chironomids)) to omnivorous fish tissue compositions. Four omnivorous fishes (Gnathopogon elongatus elongatus, Pseudorasbora parva, Biwia zezera and Tridentiger obscurus) subsisted largely on epiphytic algae and zooplankton, whereas zoobenthos contributed little to their diets. Acheilognathus rhombeus subsisted mostly on epiphytic algae. Thus, in this shallow, eutrophic lake, omnivorous fishes incorporated both littoral and pelagic production into the food web, but rarely benthic production. The dominant benthic chironomid larvae often burrow several centimetres into the sediment, and the low dietary contribution of zoobenthos to small fishes may be due to inefficiency at foraging on buried benthos associated with fish body size.

Stable isotope analysis reveals partitioning in prey use by Kajikia audax (Istiophoridae), Thunnus albacares, Katsuwonus pelamis, and Auxis spp. (Scombridae) in the Eastern Tropical Pacific of Ecuador

2021 ◽  
Vol 19 (4) ◽  
Author(s):  
Rigoberto Rosas-Luis ◽  
Nancy Cabanillas-Terán ◽  
Carmen A. Villegas-Sánchez
Keyword(s):  
Stable Isotope ◽  
Food Web ◽  
Stable Isotope Analysis ◽  
Trophic Ecology ◽  
Isotope Analysis ◽  
Middle Level ◽  
Food Sources ◽  
Thunnus Albacares ◽  
Katsuwonus Pelamis ◽  
Δ13c And Δ15n

Abstract Kajikia audax, Thunnus albacares, Katsuwonus pelamis, and Auxis spp. occupy high and middle-level trophic positions in the food web. They represent important sources for fisheries in Ecuador. Despite their ecological and economic importance, studies on pelagic species in Ecuador are scarce. This study uses stable isotope analysis to assess the trophic ecology of these species, and to determine the contribution of prey to the predator tissue. Isotope data was used to test the hypothesis that medium-sized pelagic fish species have higher δ15N values than those of the prey they consumed, and that there is no overlap between their δ13C and δ15N values. Results showed higher δ15N values for K. audax, followed by T. albacares, Auxis spp. and K. pelamis, which indicates that the highest position in this food web is occupied by K. audax. The stable isotope Bayesian ellipses demonstrated that on a long time-scale, these species do not compete for food sources. Moreover, δ15N values were different between species and they decreased with a decrease in predator size.

Food web structure of a shallow eutrophic lake (Lake Taihu, China) assessed by stable isotope analysis

Hydrobiologia ◽  
2011 ◽  
Vol 683 (1) ◽  
pp. 173-183 ◽  
Author(s):  
Zhigang Mao ◽  
Xiaohong Gu ◽  
Qingfei Zeng ◽  
Luhong Zhou ◽  
Mingbo Sun
Keyword(s):  
Stable Isotope ◽  
Food Web ◽  
Stable Isotope Analysis ◽  
Lake Taihu ◽  
Isotope Analysis ◽  
Eutrophic Lake ◽  
Food Web Structure ◽  
Web Structure ◽  
Shallow Eutrophic Lake

scholarly journals The effects of biomanipulation on the biogeochemistry, carbon isotopic composition and pelagic food web relations of a shallow lake

2006 ◽  
Vol 3 (1) ◽  
pp. 69-83 ◽  
Author(s):  
B. M. Bontes ◽  
R. Pel ◽  
B. W. Ibelings ◽  
H. T. S. Boschker ◽  
J. J. Middelburg ◽  
...  
Keyword(s):  
Food Web ◽  
Green Algae ◽  
Isotope Composition ◽  
Isotope Analysis ◽  
Carbon Isotopic Composition ◽  
Isotope Ratio Mass Spectrometry ◽  
Eutrophic Lake ◽  
Food Sources ◽  
Fish Removal ◽  
Planktonic Food

Abstract. In this study we investigated the effects of experimental biomanipulation on community structure, ecosystem metabolism, carbon biogeochemistry and stable isotope composition of a shallow eutrophic lake in the Netherlands. Three different biomanipulation treatments were applied. In two parts of the lake, isolated from the rest, fish was removed and one part was used as a reference treatment in which no biomanipulation was applied. Stable isotopes have proved useful to trace trophic interactions at higher food web levels but until now methodological limitations have restricted species specific isotope analysis in the plankton community. We applied a new approach based on the combination of fluorescence activated cell sorting (FACS) and isotope ratio mass spectrometry (IRMS) to trace carbon flow through the planktonic food web. With this method we aimed at obtaining group specific δ13C signatures of phytoplankton and to trace possible shifts in δ13C resulting from fish removal. Biomanipulation led to an increase in transparency and macrophyte biomass and decrease in phytoplankton abundance, but zooplankton numbers did not increase. Fish removal also resulted in high pH, high O2, low CO2 and more negative δ13CDIC values than expected, which is attributed to chemical enhanced diffusion with large negative fractionation. Despite high temporal variation we detected differences between the isotopic signatures of the primary producers and between the different treatments. The fractionation values of green algae (~21) and diatoms (~23) were similar and independent of treatment, while fractionation factors of filamentous cyanobacteria were variable between the treatments that differed in CO2 availability. 13C-labeling of the phytoplankton groups showed that biomanipulation led to increased growth rates of green algae and diatoms at the expense of cyanobacteria. Finally, consumers seemed generalists to the available food sources.

Dual stable isotope analysis (δ13C and δ15N) of soil invertebrates and their food sources

Pedobiologia ◽  
2004 ◽  
Vol 48 (2) ◽  
pp. 171-180 ◽  
Author(s):  
Olaf Schmidt ◽  
James P Curry ◽  
Jens Dyckmans ◽  
Emilia Rota ◽  
Charles M Scrimgeour
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Isotope Analysis ◽  
Soil Invertebrates ◽  
Food Sources ◽  
Δ13c And Δ15n

scholarly journals Diet assessments as a tool to control invasive species: comparison between Monk and Rose-ringed parakeets with stable isotopes

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
N A Borray-Escalante ◽  
D Mazzoni ◽  
A Ortega-Segalerva ◽  
L Arroyo ◽  
V Morera-Pujol ◽  
...  
Keyword(s):  
Invasive Species ◽  
Isotope Analysis ◽  
Control Measures ◽  
Food Sources ◽  
Effective Control ◽  
Limiting Factor ◽  
Δ13c And Δ15n ◽  
Isotopic Signatures ◽  
Monk Parakeet ◽  
Anthropogenic Food

Abstract Food is a main limiting factor for most populations. As a consequence, knowledge about the diet of invasive alien species determines the design of control measures. The Monk and Rose-ringed parakeets are two typical species of successful invasive parrots that are highly appreciated by people. Although some observations suggest that Monk parakeets rely on a higher percentage of anthropogenic food than Rose-ringed parakeets, no detailed quantitative data is available. The aim of this study was to compare the diet of the two parakeets using stable isotope analysis (SIA). We performed SIA of carbon and nitrogen in feathers collected in Barcelona, Spain. We also measured isotopic ratios for potential food sources. We reconstructed the diet of parakeets using Bayesian mixing models. The two species differed in the isotopic signatures of their feathers for both δ13C and δ15N. Diet reconstruction showed that Monk parakeets feed mainly on anthropogenic food (41.7%), herbaceous plants (26.9%) and leaves/seeds (22.2%), while Rose-ringed parakeets feed mainly on flowers/fruits (44.1%), anthropogenic food provided in the trap located at the museum (32.4%) and leaves/seeds (23.1%). The more detailed information we can obtain from the diet of these species is useful to develop more effective control measures for their populations. The Monk parakeet may be more susceptible to control through education local residents, given the greater use of anthropogenic food in this species compared to Rose-ringed parakeet. Our conclusions also indicate that SIA is a powerful tool in providing crucial information about the diet and informing measures to control invasive species.

scholarly journals Spatio–temporal variation in stable isotope signatures (δ13C and δ15N) of sponges on the Saba Bank

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5460 ◽  
Author(s):  
Fleur C. Van Duyl ◽  
Benjamin Mueller ◽  
Erik H. Meesters
Keyword(s):  
Organic Matter ◽  
Stable Isotope ◽  
Environmental Changes ◽  
Food Sources ◽  
Sponge Species ◽  
Isotopic Niche ◽  
Δ13c And Δ15n ◽  
Spatio Temporal ◽  
Species Specific ◽  
Potential Food

Sponges are ubiquitous on coral reefs, mostly long lived and therefore adaptive to changing environmental conditions. They feed on organic matter withdrawn from the passing water and they may harbor microorganisms (endosymbionts), which contribute to their nutrition. Their diets and stable isotope (SI) fractionation determine the SI signature of the sponge holobiont. Little is known of spatio–temporal variations in SI signatures of δ13C and δ15N in tropical sponges and whether they reflect variations in the environment. We investigated the SI signatures of seven common sponge species with different functional traits and their potential food sources between 15 and 32 m depth along the S-SE and E-NE side of the Saba Bank, Eastern Caribbean, in October 2011 and October 2013. SI signatures differed significantly between most sponge species, both in mean values and in variation, indicating different food preferences and/or fractionation, inferring sponge species-specific isotopic niche spaces. In 2011, all sponge species at the S-SE side were enriched in d13C compared to the E-NE side. In 2013, SI signatures of sponges did not differ between the two sides and were overall lighter in δ13C and δ15N than in 2011. Observed spatio–temporal changes in SI in sponges could not be attributed to changes in the SI signatures of their potential food sources, which remained stable with different SI signatures of pelagic (particulate organic matter (POM): δ13C −24.9‰, δ15N +4.3‰) and benthic-derived food (macroalgae: δ13C −15.4‰, δ15N +0.8‰). Enriched δ13C signatures in sponges at the S-SE side in 2011 are proposed to be attributed to predominantly feeding on benthic-derived C. This interpretation was supported by significant differences in water mass constituents between sides in October 2011. Elevated NO3 and dissolved organic matter concentrations point toward a stronger reef signal in reef overlying water at the S-SE than N-NE side of the Bank in 2011. The depletions of δ13C and δ15N in sponges in October 2013 compared to October 2011 concurred with significantly elevated POM concentrations. The contemporaneous decrease in δ15N suggests that sponges obtain their N mostly from benthic-derived food with a lower δ15N than pelagic food. Average proportional feeding on available sources varied between sponge species and ranged from 20% to 50% for benthic and 50% to 80% for pelagic-derived food, assuming trophic enrichment factors of 0.5‰ ± sd 0.5 for δ13C and 3‰ ± sd 0.5 for δ15N for sponges. We suggest that observed variation of SI in sponges between sides and years were the result of shifts in the proportion of ingested benthic- and pelagic-derived organic matter driven by environmental changes. We show that sponge SI signatures reflect environmental variability in space and time on the Saba Bank and that SI of sponges irrespective of their species-specific traits move in a similar direction in response to these environmental changes.

scholarly journals Variability in copepod trophic levels and feeding selectivity based on stable isotope analysis in Gwangyang Bay of the southern coast of the Korean Peninsula

2018 ◽  
Vol 15 (7) ◽  
pp. 2055-2073 ◽  
Author(s):  
Mianrun Chen ◽  
Dongyoung Kim ◽  
Hongbin Liu ◽  
Chang-Keun Kang
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Salinity Gradient ◽  
Isotope Analysis ◽  
Trophic Levels ◽  
Food Sources ◽  
Primary Producers ◽  
Model Calculations ◽  
Δ13c And Δ15n ◽  
Gwangyang Bay

Abstract. Trophic preference (i.e., food resources and trophic levels) of different copepod groups was assessed along a salinity gradient in the temperate estuarine Gwangyang Bay of Korea, based on seasonal investigation of taxonomic results in 2015 and stable isotope analysis incorporating multiple linear regression models. The δ13C and δ15N values of copepods in the bay displayed significant spatial heterogeneity as well as seasonal variations, which were indicated by their significant relationships with salinity and temperature, respectively. Both spatial and temporal variations reflected those in isotopic values of food sources. The major calanoid groups (marine calanoids and brackish water calanoids) had a mean trophic level of 2.2 relative to nanoplankton as the basal food source, similar to the bulk copepod assemblage; however, they had dissimilar food sources based on the different δ13C values. Calanoid isotopic values indicated a mixture of different genera including species with high δ15N values (e.g., Labidocera, Sinocalanus, and Tortanus), moderate values (Calanus sinicus, Centropages, Paracalanus, and Acartia), and relatively low δ15N values (Eurytemora pacifica and Pseudodiaptomus). Feeding preferences of different copepods probably explain these seasonal and spatial patterns of the community trophic niche. Bayesian mixing model calculations based on source materials of two size fractions of particulate organic matter (nanoplankton at < 20 µm vs. microplankton at 20–200 µm) indicated that Acartia and Centropages preferred large particles; Paracalanus, Calanus, Eurytemora, and Pseudodiaptomus apparently preferred small particles. Tortanus was typically carnivorous with low selectivity on different copepods. Labidocera preferred marine calanoids Acartia, Centropages, and harpacticoids; on the other hand, Sinocalanus and Corycaeus preferred brackish calanoids Paracalanus and Pseudodiaptomus. Overall, our results depict a simple energy flow of the planktonic food web of Gwangyang Bay: from primary producers (nanoplankton) and a mixture of primary producers and herbivores (microplankton) through omnivores (Acartia, Calanus, Centropages, and Paracalanus) and detritivores (Pseudodiaptomus, Eurytemora, and harpacticoids) to carnivores (Corycaeus, Tortanus, Labidocera, and Sinocalanus).

scholarly journals Variability in copepod trophic levels and in feeding selectivity based on stable isotope analysis in Gwangyang Bay off the southern coast of Korea

2017 ◽  
Author(s):  
Mianrun Chen ◽  
Dongyoung Kim ◽  
Hongbin Liu ◽  
Chang-Keun Kang
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Salinity Gradient ◽  
Isotope Analysis ◽  
Trophic Levels ◽  
Food Sources ◽  
Linear Regression Models ◽  
Model Calculations ◽  
Δ13c And Δ15n ◽  
Gwangyang Bay

Abstract. Trophism (i.e., food resources and trophic levels) of different copepod groups was assessed along a salinity gradient in the temperate estuarine Gwangyang Bay of Korea, based on seasonal investigation of taxonomic results in 2015 and stable isotope analysis incorporating multiple linear regression models. The δ13C and δ15N values of copepods in the bay displayed salinity-associated spatial heterogeneity as well as temperature-related seasonal variations. Both spatial and temporal variations reflected those in isotopic values of food sources. Three major groups (marine calanoids, brackish water calanoids and cyclopoids) had a mean trophic level of 2.2 relative to nanoplankton as the basal food source, similar to the bulk copepod assemblage; however, they had dissimilar food sources based on the different δ13C values. Calanoid isotopic values indicated a mixture of different genera including species with high δ15N values (e.g., Sinocalanus and Labidocera) and relatively low δ15N values (Paracalanus and Acartia). Feeding preferences of different copepods probably explain these seasonal and spatial patterns of the community trophic niche. Bayesian mixing model calculations based on source materials of two size fractions of particulate organic matter (nanoplankton at

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