Food-Web structure and the fractionation of Carbon isotopes in the bering sea

McConnaughey, Ted A.; McRoy, C. Peter

doi:10.1007/bf00952434

Cited by 663 publications

(601 citation statements)

References 5 publications

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“…The C:N ratio was used as an indicator of lipid content. Invertebrates, including crustacean zooplankton, tend to have a C:N ratio of 4 [25], but C:N varies seasonally [26] and was as high as 7, so we used a revised version of the lipid normalizing procedure based on the C:N ratio [27], substituting the corrected parameters into Equations (2) and (3):…”

Section: Methodsmentioning

confidence: 99%

Defining Seasonal Functional Traits of a Freshwater Zooplankton Community Using δ13C and δ15N Stable Isotope Analysis

Visconti

Caroni

Rawcliffe

et al. 2018

Water

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Abstract:Functional-based approaches are increasingly being used to define the functional diversity of aquatic ecosystems. In this study, we proposed the use of δ 13 C and δ 15 N stable isotopes as a proxy of zooplankton functional traits in Lake Maggiore, a large, deep subalpine Italian lake. We analyzed the seasonal pattern of δ 13 C and δ 15 N signatures of different crustacean zooplankton taxa to determine food sources, preferred habitats, and trophic positions of species throughout one year. The cladocerans Daphnia longispina galeata gr., Diaphanosoma brachyurum, and Eubosmina longispina were grouped into a primary consumer functional group from their δ 13 C and δ 15 N isotopic signatures, but while the former two species shared the same food sources, the latter exhibited a more selective feeding strategy. Cyclopoid copepods occupied a distinct functional group from the other secondary consumers, being the most 15 N enriched group in the lake. The δ 15 N signature of calanoid copepods showed trophic enrichment in comparison to Daphnia and Eubosmina and linear mixing model results confirmed a predator-prey relationship. In our study, we have demonstrated that the use of δ 13 C and δ 15 N stable isotopes represented an effective tool to define ecological roles of freshwater zooplankton species and to determine functional diversity in a lake.

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Section: Methodsmentioning

confidence: 99%

Defining Seasonal Functional Traits of a Freshwater Zooplankton Community Using δ13C and δ15N Stable Isotope Analysis

Visconti

Caroni

Rawcliffe

et al. 2018

Water

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“…Tissue lipid content is known to affect bulk d 13 C, as lipids are depleted in 13 C relative to proteins and carbohydrates Epstein 1977, McConnaughey andMcRoy 1979). We corrected zooplankton d 13 C data for lipid content using the mass balance equation: Smyntek et al 2007), where d 13 C ZP-M is the measured d 13 C of zooplankton, d 13 C ZP-C is the lipid-corrected d 13 C, 6.3 is the average difference in d 13 C between protein and lipids in zooplankton, and 4.2 is the C:N value of lipid extracted zooplankton (Smyntek et al 2007).…”

Section: Sample Collection and Analysismentioning

confidence: 99%

Importance of terrestrial subsidies for estuarine food webs in contrasting East African catchments

et al. 2013

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Abstract. Little is known on the degree to which terrestrial organic matter delivered to tropical estuaries contributes to estuarine consumers. Here, stable isotope analysis is used to constrain this contribution for contrasting east African estuaries whose catchments differ in relative C3/C4 vegetation cover. As these two types of vegetation differ strongly in d 13 C, we anticipated that terrestrial subsidies would be reflected in a gradient in estuarine consumer d13 C values, following the relative importance of C3 (characterised by low consumer trophic guilds, confirming the incorporation of organic material transported from the catchments by estuarine consumers, and implying that this material is transported up to high trophic level fish. Bayesian mixing models confirmed that C4 material was the most important source for the highly turbid, C4-dominated estuaries, contributing up to 61-91% (95% CI) to phytodetritivorous fish in the Betsiboka, whereas for the less turbid C3-dominated estuaries terrestrial subsidies were not as important and consumers relied on a combination of terrestrial and aquatic sources. This shows that the ecology of the overall catchment affects the estuaries at the most basic, energetic level, and activities that alter the turbidity and productivity of rivers and estuaries can affect food webs well beyond the area of impact.

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“…As our subsamples that were intended for stable isotope analysis were very small (around 0.5 cm 3 ), the separation of d 13 C and d 15 N was not feasible. Therefore, we applied a lipid normalization equation (McConnaughey and McRoy, 1979), adapted by Post et al (2007) for aquatic animals: Post et al (2007) recommend the use of a lipid normalization equation when C:N > 3.5, which corresponds to a lipid content >5% in samples. However, other authors also warn that such an equation could lead to bias if the lipid content is too high, for example, C:N > 6.5 in cormorants (Doucette et al, 2010), C:N > 7 in zooplankton (Smyntek et al, 2007) or C:N > 8 in deep-sea fish (Hoffman and Sutton, 2010).…”

Section: Stable Isotope Analysesmentioning

confidence: 99%

Toothed whales in the northwestern Mediterranean: Insight into their feeding ecology using chemical tracers

Praca

Laran²,

Lepoint

et al. 2011

Marine Pollution Bulletin

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a b s t r a c tRisso's dolphins, pilot whales and sperm whales rarely strand in the northwestern Mediterranean. Thus, their feeding ecology, through the analysis of stomach contents, is poorly known. The aim of this study was to gain further insight into the segregation/superposition of the diet and habitat of Risso's dolphins, pilot whales and sperm whales using chemical tracers, namely, stable isotopes (d N values were obtained in Risso's dolphins (11.7 ± 0.7‰), sperm whales (10.8 ± 0.3‰) and pilot whales (9.8 ± 0.3‰), revealing different trophic levels. These differences are presumably due to various proportions of Histioteuthidae cephalopods in each toothed whale's diet. Similar d 13 C contents between species indicated long-term habitat superposition or corroborated important seasonal migrations. Lower congener 180 concentrations (8.20 vs. 21.73 lg.g À1 lw) and higher tDDT/ tPCB ratios (0.93 vs. 0.42) were observed in sperm whales compared with Risso's dolphins and may indicate wider migrations for the former. Therefore, competition between these species seems to depend on different trophic levels and migration patterns.

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Food-Web structure and the fractionation of Carbon isotopes in the bering sea

Cited by 663 publications

References 5 publications

Defining Seasonal Functional Traits of a Freshwater Zooplankton Community Using δ13C and δ15N Stable Isotope Analysis

Defining Seasonal Functional Traits of a Freshwater Zooplankton Community Using δ13C and δ15N Stable Isotope Analysis

Importance of terrestrial subsidies for estuarine food webs in contrasting East African catchments

Toothed whales in the northwestern Mediterranean: Insight into their feeding ecology using chemical tracers

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