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Villamarín F, Jardine TD, Bunn SE, Malvasio A, Piña CI, Jacobi CM, Araújo DD, de Brito ES, de Moraes Carvalho F, da Costa ID, Verdade LM, Lara N, de Camargo PB, Miorando PS, Portelinha TCG, Marques TS, Magnusson WE. Body size predicts ontogenetic nitrogen stable-isotope (δ 15N) variation, but has little relationship with trophic level in ectotherm vertebrate predators. Sci Rep 2024; 14:14102. [PMID: 38890338 PMCID: PMC11189434 DOI: 10.1038/s41598-024-61969-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 05/13/2024] [Indexed: 06/20/2024] Open
Abstract
Large predators have disproportionate effects on their underlying food webs. Thus, appropriately assigning trophic positions has important conservation implications both for the predators themselves and for their prey. Large-bodied predators are often referred to as apex predators, implying that they are many trophic levels above primary producers. However, theoretical considerations predict both higher and lower trophic position with increasing body size. Nitrogen stable isotope values (δ15N) are increasingly replacing stomach contents or behavioral observations to assess trophic position and it is often assumed that ontogenetic dietary shifts result in higher trophic positions. Intraspecific studies based on δ15N values found a positive relationship between size and inferred trophic position. Here, we use datasets of predatory vertebrate ectotherms (crocodilians, turtles, lizards and fishes) to show that, although there are positive intraspecific relationships between size and δ15N values, relationships between stomach-content-based trophic level (TPdiet) and size are undetectable or negative. As there is usually no single value for 15N trophic discrimination factor (TDF) applicable to a predator species or its prey, estimates of trophic position based on δ15N in ectotherm vertebrates with large size ranges, may be inaccurate and biased. We urge a reconsideration of the sole use of δ15N values to assess trophic position and encourage the combined use of isotopes and stomach contents to assess diet and trophic level.
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Affiliation(s)
- Francisco Villamarín
- Grupo de Biogeografía y Ecología Espacial (BioGeoE2), Universidad Regional Amazónica Ikiam, Tena, Ecuador.
| | - Timothy D Jardine
- School of Environment and Sustainability, University of Saskatchewan, Saskatoon, SK, Canada
| | - Stuart E Bunn
- Australian Rivers Institute, Griffith University, Nathan, QLD, Australia
| | - Adriana Malvasio
- Laboratório de Ecologia e Zoologia (LABECZ), Curso de Engenharia Ambiental, Universidade Federal do Tocantins, Palmas, TO, Brazil
| | - Carlos Ignacio Piña
- Centro de Investigación Científica y de Transferencia Tecnológica a la Producción (Consejo Nacional de Investigaciones Científicas y Técnicas, Provincia de Entre Ríos, Universidad Autónoma de Entre Ríos), Diamante, Argentina
| | | | - Diogo Dutra Araújo
- Laboratório de Ecologia de Vertebrados Terrestres (LEVERT), Universidade do Vale do Rio dos Sinos, São Leopoldo, RS, Brazil
| | | | | | - Igor David da Costa
- Instituto do Noroeste Fluminense de Educação Superior, Universidade Federal Fluminense, Santo Antônio de Pádua, RJ, Brazil
| | | | - Neliton Lara
- Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, Piracicaba, Brazil
| | | | | | - Thiago Costa Gonçalves Portelinha
- Laboratório de Caracterização de Impactos Ambientais (LCIA), Curso de Engenharia Ambiental, Universidade Federal do Tocantins, Palmas, TO, Brazil
| | - Thiago Simon Marques
- Laboratório de Ecologia Aplicada, Núcleo de Estudos Ambientais, Universidade de Sorocaba, Sorocaba, Brazil
| | - William E Magnusson
- Coordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil
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Raoult V, Phillips AA, Nelson J, Niella Y, Skinner C, Tilcock MB, Burke PJ, Szpak P, James WR, Harrod C. Why aquatic scientists should use sulfur stable isotope ratios (ẟ 34S) more often. CHEMOSPHERE 2024; 355:141816. [PMID: 38556184 DOI: 10.1016/j.chemosphere.2024.141816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 02/26/2024] [Accepted: 03/25/2024] [Indexed: 04/02/2024]
Abstract
Over the last few decades, measurements of light stable isotope ratios have been increasingly used to answer questions across physiology, biology, ecology, and archaeology. The vast majority analyse carbon (δ13C) and nitrogen (δ15N) stable isotopes as the 'default' isotopes, omitting sulfur (δ34S) due to time, cost, or perceived lack of benefits and instrumentation capabilities. Using just carbon and nitrogen isotopic ratios can produce results that are inconclusive, uncertain, or in the worst cases, even misleading, especially for scientists that are new to the use and interpretation of stable isotope data. Using sulfur isotope values more regularly has the potential to mitigate these issues, especially given recent advancements that have lowered measurement barriers. Here we provide a review documenting case studies with real-world data, re-analysing different biological topics (i.e. niche, physiology, diet, movement and bioarchaeology) with and without sulfur isotopes to highlight the various strengths of this stable isotope for various applications. We also include a preliminary meta-analysis of the trophic discrimination factor (TDF) for sulfur isotopes, which suggest small (mean -0.4 ± 1.7 ‰ SD) but taxa-dependent mean trophic discrimination. Each case study demonstrates how the exclusion of sulfur comes at the detriment of the results, often leading to very different outputs, or missing valuable discoveries entirely. Given that studies relying on carbon and nitrogen stable isotopes currently underpin most of our understanding of various ecological processes, this has concerning implications. Collectively, these examples strongly suggest that researchers planning to use carbon and nitrogen stable isotopes for their research should incorporate sulfur where possible, and that the new 'default' isotope systems for aquatic science should now be carbon, nitrogen, and sulfur.
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Affiliation(s)
- Vincent Raoult
- Blue Carbon Lab, School of Life and Environmental Science, Deakin University, VIC, Australia; Marine Ecology Group, School of Natural Sciences, Macquarie University, NSW, Australia.
| | - Alexandra A Phillips
- National Center for Ecological Analysis and Synthesis, University of California Santa Barbara, Santa Barbara, CA, USA
| | - James Nelson
- Department of Marine Science, University of Georgia, Athens, GA, USA
| | - Yuri Niella
- Marine Ecology Group, School of Natural Sciences, Macquarie University, NSW, Australia
| | - Christina Skinner
- Marine Spatial Ecology Lab, School of Biological Sciences, University of Queensland, QLD, Australia
| | | | - Patrick J Burke
- Marine Ecology Group, School of Natural Sciences, Macquarie University, NSW, Australia
| | - Paul Szpak
- Department of Anthropology, Trent University, Peterborough, Ontario, Canada
| | - W Ryan James
- Institute of Environment, Florida International University, Miami, FL, USA
| | - Chris Harrod
- Instituto Ciencias Naturales Alexander von Humboldt, Universidad de Antofagasta, Antofagasta, Chile; Millennium Nucleus INVASAL, Concepción, Chile; Universidad de Antofagasta Stable Isotope Facility, Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
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3
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Rogers MC, Heintz RA, Vollenweider JJ, Sreenivasan A, Miller KB. Climate change-informed dietary modeling in Pacific cod: Experimentally-derived effects of temperature and dietary quality on carbon and nitrogen stable isotope trophic discrimination factors. PLoS One 2023; 18:e0295564. [PMID: 38060595 PMCID: PMC10703269 DOI: 10.1371/journal.pone.0295564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 11/22/2023] [Indexed: 12/18/2023] Open
Abstract
Stable isotope analysis is a powerful tool for dietary modeling and trophic ecology research. A crucial piece of information for isotopic dietary modeling is the accurate estimation of trophic discrimination factors (TDFs), or the isotopic offset between a consumer's tissue and its diet. In order to parameterize stable isotope dietary models for future climate scenarios, we investigated the effect of water temperature and dietary protein and lipid content on TDFs in juvenile Pacific cod (Gadus macrocephalus). Pacific cod are a commercially and ecologically important species, with stock numbers in the northeast Pacific recently having dropped by more than 70%. We tested four water temperatures (6, 8, 10, and 12°C) and two dietary regimens (low and high lipid content), representing a range of potential ocean temperature and prey quality scenarios, in order to determine carbon and nitrogen TDFs in juvenile Pacific cod. Additionally, we assessed dietary intake and proximate composition of the experimental fish in order to estimate consumption, assimilation, and retention of dietary nutrients. The results of this study suggest that dietary protein catabolism is a primary driver of nitrogen TDF variability in juvenile Pacific cod. Across all temperature treatments from 6 to 12°C, fish reared on the lower quality, lower lipid content diet had higher nitrogen TDFs. The mean TDFs for fish raised on the higher lipid, lower protein diet were +3.40 ‰ for nitrogen (Δ15N) and +0.36 ‰ for lipid-corrected carbon (Δ LC 13C). The mean TDFs for fish raised on the lower lipid, higher protein diet were +4.09 ‰ for nitrogen (Δ15N) and 0.00 ‰ for lipid-corrected carbon (Δ LC 13C). Lipid-corrected carbon isotope data showed that, regardless of temperature, fish consuming the lower lipid diet had essentially no trophic discrimination between diet and bulk tissues. We found no ecologically meaningful differences in TDFs due to water temperature across the 6°experimental range. The results of this experiment demonstrate that dietary quality, and more specifically the use of dietary protein for energetic needs, is a primary driver of trophic discrimination factors. The TDFs determined in this study can be applied to understanding trophic ecology in Pacific cod and closely related species under rapidly changing prey availability and ocean temperature conditions.
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Affiliation(s)
- Matthew C. Rogers
- NOAA, National Marine Fisheries Service, Alaska Fisheries Science Center, Auke Bay Laboratories, Juneau, Alaska, United States of America
| | - Ron A. Heintz
- Sitka Sound Science Center, Sitka, Alaska, United States of America
| | - Johanna J. Vollenweider
- NOAA, National Marine Fisheries Service, Alaska Fisheries Science Center, Auke Bay Laboratories, Juneau, Alaska, United States of America
| | - Ashwin Sreenivasan
- University of Alaska Southeast, Juneau, Alaska, United States of America
| | - Katharine B. Miller
- NOAA, National Marine Fisheries Service, Alaska Fisheries Science Center, Auke Bay Laboratories, Juneau, Alaska, United States of America
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4
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Andrade D, García-Cegarra AM, Docmac F, Ñacari LA, Harrod C. Multiple stable isotopes (C, N & S) provide evidence for fin whale (Balaenoptera physalus) trophic ecology and movements in the Humboldt Current System of northern Chile. MARINE ENVIRONMENTAL RESEARCH 2023; 192:106178. [PMID: 37776807 DOI: 10.1016/j.marenvres.2023.106178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 09/04/2023] [Accepted: 09/11/2023] [Indexed: 10/02/2023]
Abstract
Reflecting the intense coastal upwelling and high primary productivity characteristic of the Humboldt Current System (HCS), the northern coast of Chile supports a diverse and productive community of marine consumers, including worldwide important pelagic fisheries resources. Although marine mammals are relatively understudied in the region, recent studies have demonstrated that fin whale (Balaenoptera physalus) is the most frequently encountered whale species, and forages in these waters year-round. However, a current lack of information limits our understanding of whether fin whales actively feed and/or remain resident in these waters or whether whales are observed feeding as they migrate along this part of the Pacific. Here, we use stable isotope ratios of carbon, nitrogen and sulphur of fin whale skin samples collected in early summer 2020 (n = 18) and in late winter 2021 (n = 22) to examine evidence of temporal isotopic shifts that could provide information on potential migratory movements and to estimate likely consumption patterns of putative prey (i.e. zooplankton, krill, pelagic fishes and Pleuroncodes sp.). We also analysed prey items in fin whale faecal plumes (n = 8) collected during the study period. Stable isotope data showed significant differences in the isotopic values of fin whales from summer and winter. On average, summer individuals were depleted in 15N and 34S relative to those sampled during winter. Whales sampled in summer showed greater isotopic variance than winter individuals, with several showing values that were atypical for consumers from the HCS. During winter, fin whales showed far less inter-individual variation in stable isotope values, and all individuals had values indicative of prey consumption in the region. Analysis of both stable isotopes and faeces indicated that fin whales sighted off the Mejillones Peninsula fed primarily on krill (SIA median contribution = 32%; IRI = 65%) and, to a lesser extent, zooplankton (SIA zooplankton = 29%; IRI copepod = 33%). These are the first isotopic-based data regarding the trophic ecology of fin whales in the north of Chile. They provide evidence that fin whales are seasonally resident in the area, including individuals with values that likely originated outside the study area. The information presented here serves as a baseline for future work. It highlights that many aspects of the ecology of fin whales in the Humboldt Current and wider SE Pacific still need to be clarified.
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Affiliation(s)
- Diego Andrade
- Programa de Magíster en Ecología de Sistemas Acuáticos, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta Chile, Chile; Instituto de Ciencias Naturales Alexander von Humboldt, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Chile
| | - Ana M García-Cegarra
- Instituto de Ciencias Naturales Alexander von Humboldt, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Chile; Laboratorio de Estudio de Megafauna Marina, CETALAB, Universidad de Antofagasta, Chile.
| | - Felipe Docmac
- Instituto de Ciencias Naturales Alexander von Humboldt, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Chile; Universidad de Antofagasta Stable Isotope Facility, Instituto Antofagasta, Universidad de Antofagasta, Chile; INVASAL, Concepción, Chile
| | - Luis A Ñacari
- Universidad de Antofagasta Stable Isotope Facility, Instituto Antofagasta, Universidad de Antofagasta, Chile; INVASAL, Concepción, Chile; Laboratorio de Ecología y Evolución de Parásitos, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Chile
| | - Chris Harrod
- Instituto de Ciencias Naturales Alexander von Humboldt, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Chile; Universidad de Antofagasta Stable Isotope Facility, Instituto Antofagasta, Universidad de Antofagasta, Chile; INVASAL, Concepción, Chile
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5
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Yurkowski DJ, McCulloch E, Ogloff WR, Johnson KF, Amiraux R, Basu N, Elliott KH, Fisk AT, Ferguson SH, Harris LN, Hedges KJ, Jacobs K, Loewen TN, Matthews CJD, Mundy CJ, Niemi A, Rosenberg B, Watt CA, McKinney MA. Mercury accumulation, biomagnification, and relationships to δ 13C, δ 15N and δ 34S of fishes and marine mammals in a coastal Arctic marine food web. MARINE POLLUTION BULLETIN 2023; 193:115233. [PMID: 37421916 DOI: 10.1016/j.marpolbul.2023.115233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/26/2023] [Accepted: 06/27/2023] [Indexed: 07/10/2023]
Abstract
Combining mercury and stable isotope data sets of consumers facilitates the quantification of whether contaminant variation in predators is due to diet, habitat use and/or environmental factors. We investigated inter-species variation in total Hg (THg) concentrations, trophic magnification slope between δ15N and THg, and relationships of THg with δ13C and δ34S in 15 fish and four marine mammal species (249 individuals in total) in coastal Arctic waters. Median THg concentration in muscle varied between species ranging from 0.08 ± 0.04 μg g-1 dw in capelin to 3.10 ± 0.80 μg g-1 dw in beluga whales. Both δ15N (r2 = 0.26) and δ34S (r2 = 0.19) best explained variation in log-THg across consumers. Higher THg concentrations occurred in higher trophic level species that consumed more pelagic-associated prey than consumers that rely on the benthic microbial-based food web. Our study illustrates the importance of using a multi-isotopic approach that includes δ34S when investigating trophic Hg dynamics in coastal marine systems.
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Affiliation(s)
- David J Yurkowski
- Arctic and Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada; Department of Biological Science, University of Manitoba, Winnipeg, Manitoba, Canada.
| | - Elena McCulloch
- Department of Natural Resource Sciences, McGill University, Ste. Anne de Bellevue, Quebec, Canada
| | - Wesley R Ogloff
- Arctic and Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada; Integrative Biology, University of Windsor, Windsor, Ontario, Canada
| | - Kelsey F Johnson
- Arctic and Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada
| | - Rémi Amiraux
- Centre for Earth Observation Science, Department of Environment and Geography, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Niladri Basu
- Faculty of Agricultural and Environmental Sciences, McGill University, Montreal, Canada
| | - Kyle H Elliott
- Department of Natural Resource Sciences, McGill University, Ste. Anne de Bellevue, Quebec, Canada
| | - Aaron T Fisk
- School of the Environment, University of Windsor, Windsor, Ontario, Canada
| | - Steven H Ferguson
- Arctic and Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada; Department of Biological Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Les N Harris
- Arctic and Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada
| | - Kevin J Hedges
- Arctic and Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada
| | - Kevin Jacobs
- Arctic and Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada
| | - Tracey N Loewen
- Arctic and Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada
| | - Cory J D Matthews
- Arctic and Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada; Department of Biological Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - C J Mundy
- Centre for Earth Observation Science, Department of Environment and Geography, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Andrea Niemi
- Arctic and Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada
| | - Bruno Rosenberg
- Arctic and Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada
| | - Cortney A Watt
- Arctic and Aquatic Research Division, Fisheries and Oceans Canada, Winnipeg, Manitoba, Canada; Department of Biological Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Melissa A McKinney
- Department of Natural Resource Sciences, McGill University, Ste. Anne de Bellevue, Quebec, Canada
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Ziegler AF, Bluhm BA, Renaud PE, Jørgensen LL. Isotopic turnover in polar cod (Boreogadus saida) muscle determined through a controlled feeding experiment. JOURNAL OF FISH BIOLOGY 2023; 102:1442-1454. [PMID: 36999199 DOI: 10.1111/jfb.15389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 03/29/2023] [Indexed: 06/09/2023]
Abstract
Polar cod (Boreogadus saida) is an important trophic link within Arctic marine food webs and is likely to experience diet shifts in response to climate change. One important tool for assessing organism diet is bulk stable isotope analysis. However, key parameters necessary for interpreting the temporal context of stable isotope values are lacking, especially for Arctic species. This study provides the first experimental determination of isotopic turnover (as half-life) and trophic discrimination factors (TDFs) of both δ13 C and δ15 N in adult polar cod muscle. Using a diet enriched in both 13 C and 15 N, we measured isotopic turnover times of 61 and 49 days for δ13 C and δ15 N, respectively, with metabolism accounting for >94% of the total turnover. These half-life estimates are valid for adult polar cod (>3 years) experiencing little somatic growth. We measured TDFs in our control of 2.6‰ and 3.9‰ for δ13 C and δ15 N, respectively, and we conclude that applying the commonly used TDF of ~1‰ for δ13 C for adult polar cod may lead to misrepresentation of dietary carbon source, while the use of 3.8‰ for δ15 N is appropriate. Based on these results, we recommend that studies investigating seasonal shifts in the diet of adult polar cod sample at temporal intervals of at least 60 days to account for isotopic turnover in polar cod muscle. Although isotopic equilibrium was reached by the fish in this study, it was at substantially lower isotope values than the diet. Additionally, the use of highly enriched algae in the experimental feed caused very high variability in diet isotope values which precluded accurate calculation of TDFs from the enriched fish. As a result of the challenges faced in this study, we discourage the use of highly enriched diets for similar experiments and provide recommendations to guide the design of future isotopic turnover experiments.
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Affiliation(s)
- Amanda Fern Ziegler
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
- Institute of Marine Research, Fram Centre, Tromsø, Norway
| | - Bodil A Bluhm
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
| | - Paul E Renaud
- Akvaplan-niva, Fram Centre for Climate and the Environment, Tromsø, Norway
- University Centre in Svalbard, Longyearbyen, Norway
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Thera JC, Kidd KA, Stewart AR, Bertolo RF, O'Driscoll NJ. Using tissue cysteine to predict the trophic transfer of methylmercury and selenium in lake food webs. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 311:119936. [PMID: 35964789 DOI: 10.1016/j.envpol.2022.119936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 08/03/2022] [Accepted: 08/07/2022] [Indexed: 06/15/2023]
Abstract
The biomagnification of toxic methylmercury (MeHg) and selenium (Se) through aquatic food webs using nitrogen stable isotopes (δ15N) varies among ecosystems but underlying mechanisms are yet unexplained. Given the strong links between MeHg and thiol-containing amino acids and proteins containing selenocysteine, our hypothesis was that cysteine content is a better predictor of MeHg and Se transfer through lake food webs than δ15N. Food web samples were collected from six lakes in Kejimkujik National Park, Nova Scotia, Canada, and the regression slopes of log MeHg or Se versus protein-bound cysteine or bulk δ15N were compared. Across all six lakes, MeHg varied by a factor of 10 among taxa and was significantly and positively related to both cysteine (R2 = 0.65-0.80, p < 0.001) and δ15N (R2 = 0.88-0.94, p < 0.001), with no among-system differences in these slopes. In contrast, total Se concentrations varied by less than a factor of 2 among taxa in four lakes and were significantly related to cysteine in only two food webs (R2 = 0.20 & 0.37, p = 0.014 & < 0.001); however, δ15N was not a predictor of Se in any lake (p = 0.052-0.777). Overall, these novel results indicate that cysteine content predicts MeHg, and sometimes Se, across trophic levels, providing a potential mechanism for among-system differences in their biomagnification.
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Affiliation(s)
- Jennifer C Thera
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, NB, Canada
| | - Karen A Kidd
- Canadian Rivers Institute and Department of Biology, University of New Brunswick, Saint John, NB, Canada; Department of Biology & School of Earth, Environment and Society, McMaster University, Hamilton, ON, Canada.
| | | | - Robert F Bertolo
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Nelson J O'Driscoll
- Department of Earth and Environmental Science, Acadia University, Wolfville, NS, Canada
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Jimbo M, Ishinazaka T, Shirane Y, Umemura Y, Yamanaka M, Uno H, Sashika M, Tsubota T, Shimozuru M. Diet selection and asocial learning: Natal habitat influence on lifelong foraging strategies in solitary large mammals. Ecosphere 2022. [DOI: 10.1002/ecs2.4105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Mina Jimbo
- Faculty of Veterinary Medicine Hokkaido University Sapporo Japan
| | | | - Yuri Shirane
- Faculty of Veterinary Medicine Hokkaido University Sapporo Japan
- Hokkaido Research Organization Sapporo Japan
| | | | | | - Hiroyuki Uno
- Faculty of Agriculture Tokyo University of Agriculture and Technology Tokyo Japan
| | - Mariko Sashika
- Faculty of Veterinary Medicine Hokkaido University Sapporo Japan
| | - Toshio Tsubota
- Faculty of Veterinary Medicine Hokkaido University Sapporo Japan
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9
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Reevaluating trophic discrimination factors (
Δδ
13
C
and
Δδ
15
N
) for diet reconstruction. ECOL MONOGR 2022. [DOI: 10.1002/ecm.1525] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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10
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Alp M, Cucherousset J. Food webs speak of human impact: Using stable isotope-based tools to measure ecological consequences of environmental change. FOOD WEBS 2022. [DOI: 10.1016/j.fooweb.2021.e00218] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Inferences to estimate consumer’s diet using stable isotopes: Insights from a dynamic mixing model. PLoS One 2022; 17:e0263454. [PMID: 35130334 PMCID: PMC8820609 DOI: 10.1371/journal.pone.0263454] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 01/19/2022] [Indexed: 12/04/2022] Open
Abstract
Stable isotope ratios are used to reconstruct animal diet in trophic ecology via mixing models. Several assumptions of stable isotope mixing models are critical, i.e., constant trophic discrimination factor and isotopic equilibrium between the consumer and its diet. The isotopic turnover rate (λ and its counterpart the half-life) affects the dynamics of isotopic incorporation for an organism and the isotopic equilibrium assumption: λ involves a time lag between the real assimilated diet and the diet estimated by mixing models at the individual scale. Current stable isotope mixing model studies consider neither this time lag nor even the dynamics of isotopic ratios in general. We developed a mechanistic framework using a dynamic mixing model (DMM) to assess the contribution of λ to the dynamics of isotopic incorporation and to estimate the bias induced by neglecting the time lag in diet reconstruction in conventional static mixing models (SMMs). The DMM includes isotope dynamics of sources (denoted δs), λ and frequency of diet-switch (ω). The results showed a significant bias generated by the SMM compared to the DMM (up to 50% of differences). This bias can be strongly reduced in SMMs by averaging the isotopic variations of the food sources over a time window equal to twice the isotopic half-life. However, the bias will persist (∼15%) for intermediate values of the ω/λ ratio. The inferences generated using a case study highlighted that DMM enhanced estimates of consumer’s diet, and this could avoid misinterpretation in ecosystem functioning, food-web structure analysis and underlying biological processes.
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12
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Javornik J, Šturm MB, Jerina K. Four approaches for estimating isotope discrimination factors produce contrasting dietary estimates for bears. URSUS 2021. [DOI: 10.2192/ursus-d-19-00028.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Jernej Javornik
- University of Ljubljana, Biotechnical faculty, Department of Forestry, Večna pot 83, 1000 Ljubljana, Slovenia
| | - Martina Burnik Šturm
- University of Natural Resources and Life Sciences (BOKU), Institute of Analytical Chemistry, Mutgasse 18, 1190 Vienna, Austria
| | - Klemen Jerina
- University of Ljubljana, Biotechnical faculty, Department of Forestry, Večna pot 83, 1000 Ljubljana, Slovenia
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13
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Hewitt DE, Taylor MD, Raoult V, Smith TM, Gaston TF. Diet-tissue discrimination and turnover of δ 13 C and δ 15 N in muscle tissue of a penaeid prawn. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2021; 35:e9167. [PMID: 34494325 DOI: 10.1002/rcm.9167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 07/13/2021] [Accepted: 07/16/2021] [Indexed: 06/13/2023]
Abstract
RATIONALE Stable isotopes are used to study trophic and movement ecology in aquatic systems, as they provide spatially distinct, time-integrated signatures of diet. Stable isotope ecology has been used to quantify species-habitat relationships in many important fisheries species (e.g., penaeid prawns), with approaches that typically assume constant values for diet-tissue discrimination and diet-tissue steady state, but these can be highly variable. Here we provide the first report of these processes in Metapenaeus macleayi (eastern school prawn). METHODS Here we explicitly measure and model carbon (δ13 C) and nitrogen (δ15 N) diet-tissue discrimination and turnover in eastern school prawn muscle tissue as a function of experimental time following a change in diet to an isotopically distinct food source. RESULTS Diet-tissue discrimination factors were 5 and 0.6‰ for δ13 C and δ15 N, respectively. Prawn muscle tissue reached an approximate steady state after approximately 50 and 30 days for δ13 C and δ15 N. Half-lives indicated faster turnover of δ15 N (~8 days) than δ13 C (~14 days). CONCLUSIONS Our diet-tissue discrimination factors deviate from 'typical' values with larger values for carbon than nitrogen isotopes, but are generally similar to those measured in other crustaceans. Similarly, our estimates of isotopic turnover align with those in other penaeid species. These findings confirm muscle tissue as a reliable indicator of long-term diet and movement patterns in eastern school prawn.
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Affiliation(s)
- Daniel E Hewitt
- School of Environmental and Life Sciences, University of Newcastle, Ourimbah, NSW, Australia
| | - Matthew D Taylor
- School of Environmental and Life Sciences, University of Newcastle, Ourimbah, NSW, Australia
- New South Wales Department of Primary Industries, Port Stephens Fisheries Institute, Nelson Bay, NSW, Australia
| | - Vincent Raoult
- School of Environmental and Life Sciences, University of Newcastle, Ourimbah, NSW, Australia
| | - Timothy M Smith
- School of Environmental and Life Sciences, University of Newcastle, Ourimbah, NSW, Australia
- Centre for Tropical Water and Aquatic Ecosystems Research (TropWATER), James Cook University, Cairns, QLD, Australia
| | - Troy F Gaston
- School of Environmental and Life Sciences, University of Newcastle, Ourimbah, NSW, Australia
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14
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Hopkins JB, Ferguson JM, Frederick C, Jerina K. Measuring the impact of corn on mammalian omnivores. J Mammal 2021. [DOI: 10.1093/jmammal/gyaa152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
In human-dominated landscapes throughout the world, wildlife seek out anthropogenic foods because they are high in nutritional value and are consistently available. To investigate this mode of foraging, some researchers use stable isotope analysis to detect these animals in populations and estimate their individual diets. In this study, we develop an integrative approach to measure the proportion of corn, a C4 plant, in the diets of free-ranging mammalian omnivores in C3-dominated ecosystems. We fed captive mice corn, C3 plants, and meat until carbon stable isotopes (δ 13C) from each diet equilibrated in their hair. We then used carbon discrimination factors (Δ 13C; offsets between stable isotope values of consumer tissues and their foods) for mice from these feeding trials and a simple carbon stable isotope mixing model to estimate the corn-based diets of free-ranging American black bears in Wisconsin and brown bears in Slovenia. We used Δ 13C factors for mice to estimate the diets of bears because mouse models are used commonly to study mammalian diet and health, including humans and bears, and body mass has no effect on carbon discrimination factors in monogastric mammalian omnivores. In this study, we found that mice grew fastest, largest, and δ 13C values equilibrated quickest in the hair of mice fed meat versus plant-based diets, suggesting protein quantity (quality was the same) has an effect on Δ 13C. Evidence also suggests that Δ 13C did not increase with animal growth rate as all mice grew throughout the 109-day feeding trials, but isotopic equilibration occurred early while mice still were subadults and was maintained throughout their adult lives. We also found that Δ 13C was highest and most variable in the hair, serum, and liver, of mice fed a mixed diet of C3 plants, supporting our mixed diet hypothesis that states that Δ 13C varies more among tissues of animals fed mixed diets than animals fed nonmixed diets because the former are composed of multiple foods, each with different macromolecular and isotopic compositions. Lastly, we found that corn may have been a more important component of bear diets in Wisconsin than previously thought (adults: x¯ = 29%; x¯ = 33%; subadults: x¯ = 22%; x¯ = 28%), and male brown bears may have fed on 50% more corn (x¯ = 47% versus 31%) in autumn during a year when beechnut availability was low. In a world that is rapidly changing, it is more important than ever to develop the appropriate quantitative tools to measure the impact people have on wildlife. Here, we provide such a tool for monogastric mammalian omnivores and encourage other researchers to do the same for other taxa of interest.
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Affiliation(s)
- John B Hopkins
- Center for Wildlife Studies, North Yarmouth, ME, USA
- University of Ljubljana, Biotechnical Faculty, Department of Forestry and Renewable Forest Resources, Večna pot 83, 1000 Ljubljana, Slovenia
| | - Jake M Ferguson
- School of Life Sciences, University of Hawai’i at Mānoa, Honolulu, HI, USA
| | | | - Klemen Jerina
- University of Ljubljana, Biotechnical Faculty, Department of Forestry and Renewable Forest Resources, Večna pot 83, 1000 Ljubljana, Slovenia
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15
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Elliott KH, Braune BM, Elliott JE. Beyond bulk δ 15N: Combining a suite of stable isotopic measures improves the resolution of the food webs mediating contaminant signals across space, time and communities. ENVIRONMENT INTERNATIONAL 2021; 148:106370. [PMID: 33476789 DOI: 10.1016/j.envint.2020.106370] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 11/27/2020] [Accepted: 12/22/2020] [Indexed: 06/12/2023]
Abstract
Top predators are used as indicators of contaminant trends across space and time. However, signals are integrated over complex food webs, and variation in diet may confound such signals. Trophic position, assessed by bulk δ15N, is widely used to infer the variation in diet relevant to contamination, yet a single variable cannot completely describe complex food webs. Thus, we examined relationships across three aquatic systems varying from a single species to a small food web using bulk values from four isotopes and 21 amino acid-specific values. Because variation in baseline ('source') δ15N can confound estimates of trophic position , we calculated trophic position from the difference between δ15Ntrophic (δ15N for amino acids that change with trophic position) and δ15Nsource (δ15N for amino acids that do not change with trophic position). Across all three systems, variation in δ15Nsource explained over half of the variation in bulk δ15N, and stable isotope values that reflected the base of the food web (δ13C, δ18O, δ34S) predicted contaminants as well or better than δ15N-which was supported by a meta-analysis of other studies. In ospreys feeding in lakes, variation in δ15Nsource across space created a spurious relationship between ΣDDT and apparent trophic position, and masked a relationship between ΣPCB and trophic position. In a seabird guild, changes in diet over time obscured temporal variation in contaminants over five decades. In Arctic fish and invertebrates, more accurate trophic magnification factors were calculated using δ15Ntrophic-source. Thus, (1) using δ15Ntrophic-source, instead of bulk δ15N, avoided incorrect conclusions and improved accuracy of trophic magnification factors necessary to assess risk to top predators; and (2) diet assessed with multiple spatial isotopes, rather than δ15N alone, was essential to understand patterns in contaminants across space, time and biological communities. Trophic position was most important for lipophilic 'legacy' contaminants (ΣDDT, ΣPCB) and habitat was most important for other contaminants (ΣPBDE, ΣPFAS, mercury). We argue that the use of amino acid-specific analysis of δ15N alongside 'non-trophic' isotopes should be a core feature of any study that examines the influence of trophic position on chemical pollution, as required for a chemical to be added to international conventions such as the Stockholm Convention.
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Affiliation(s)
- Kyle H Elliott
- Department of Natural Resource Sciences, McGill University, Sainte Anne-de-Bellevue H9X 3V9, Canada.
| | - Birgit M Braune
- Science & Technology Branch, Environment and Climate Change Canada, Ottawa K1A 0H3, Canada
| | - John E Elliott
- Science & Technology Branch, Environment and Climate Change Canada, Delta V4K 3N2, Canada
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16
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Hoondert RPJ, van den Brink NW, van den Heuvel-Greve MJ, Ragas AMJ, Hendriks AJ. Variability in nitrogen-derived trophic levels of Arctic marine biota. Polar Biol 2020. [DOI: 10.1007/s00300-020-02782-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
AbstractStable isotopes are often used to provide an indication of the trophic level (TL) of species. TLs may be derived by using food-web-specific enrichment factors in combination with a representative baseline species. It is challenging to sample stable isotopes for all species, regions and seasons in Arctic ecosystems, e.g. because of practical constraints. Species-specific TLs derived from a single region may be used as a proxy for TLs for the Arctic as a whole. However, its suitability is hampered by incomplete knowledge on the variation in TLs. We quantified variation in TLs of Arctic species by collating data on stable isotopes across the Arctic, including corresponding fractionation factors and baseline species. These were used to generate TL distributions for species in both pelagic and benthic food webs for four Arctic areas, which were then used to determine intra-sample, intra-study, intra-region and inter-region variation in TLs. Considerable variation in TLs of species between areas was observed. This is likely due to differences in parameter choice in estimating TLs (e.g. choice of baseline species) and seasonal, temporal and spatial influences. TLs between regions were higher than the variance observed within regions, studies or samples. This implies that TLs derived within one region may not be suitable as a proxy for the Arctic as a whole. The TL distributions derived in this study may be useful in bioaccumulation and climate change studies, as these provide insight in the variability of trophic levels of Arctic species.
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17
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Stable isotopes verify geographical origin of yak meat from Qinghai-Tibet plateau. Meat Sci 2020; 165:108113. [DOI: 10.1016/j.meatsci.2020.108113] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 03/13/2020] [Accepted: 03/13/2020] [Indexed: 11/21/2022]
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18
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Nutritional stress by means of high C:N ratios in the diet and starvation affects nitrogen isotope ratios and trophic fractionation of omnivorous copepods. Oecologia 2019; 190:547-557. [DOI: 10.1007/s00442-019-04438-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 06/17/2019] [Indexed: 11/27/2022]
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19
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Thieltges DW, Goedknegt MA, O'Dwyer K, Senior AM, Kamiya T. Parasites and stable isotopes: a comparative analysis of isotopic discrimination in parasitic trophic interactions. OIKOS 2019. [DOI: 10.1111/oik.06086] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- David W. Thieltges
- NIOZ Royal Netherlands Inst. for Sea Research, Dept of Coastal Systems, and Utrecht Univ. PO Box 59 NL‐1790 AB Den Burg Texel the Netherlands
| | - M. Anouk Goedknegt
- NIOZ Royal Netherlands Inst. for Sea Research, Dept of Coastal Systems, and Utrecht Univ. PO Box 59 NL‐1790 AB Den Burg Texel the Netherlands
| | - Katie O'Dwyer
- Marine and Freshwater Research Centre, Galway‐Mayo Inst. of Technology Galway Ireland
| | - Alistair M. Senior
- Charles Perkins Centre and School of Life, and: Environmental Sciences, and School of Mathematics and Statistics, Univ. of Sydney Sydney New South Wales Australia
| | - Tsukushi Kamiya
- Dept of Ecology and Evolutionary Biology, Univ. of Toronto Toronto ON Canada
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20
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Kambikambi MJ, Chakona A, Kadye WT. The influence of diet composition and tissue type on the stable isotope incorporation patterns of a small-bodied southern African minnow Enteromius anoplus (Cypriniformes, Cyprinidae). RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2019; 33:613-623. [PMID: 30672616 DOI: 10.1002/rcm.8393] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 01/17/2019] [Accepted: 01/17/2019] [Indexed: 06/09/2023]
Abstract
RATIONALE In trophic ecology, the use of stable isotope data relies on the general understanding of isotope turnover rates and diet-to-tissue discrimination factors (DTDFs). Recent studies on the application of stable isotope data have shown that isotope turnover rates and DTDFs can be influenced by many factors, including diet composition and tissue type. This study investigated the influence of diet composition and tissue type on stable isotope incorporation patterns in a small-bodied African minnow, the chubbyhead barb Enteromius anoplus. METHODS The isotopic incorporation patterns of carbon (δ13 C values) and nitrogen (δ15 N values) into white muscle and caudal fin tissues of the chubbyhead barb were examined using two isotopically different diets. Controlled-diet stable isotope feeding trials using a fishmeal-based diet (diet 1) and a soya-based diet (diet 2) were conducted over a 180-day period for the chubbyhead barb. RESULTS The two diets had contrasting isotopic incorporation patterns: diet 1 was associated with progressively high δ13 C and δ15 N values, whereas diet 2 was associated with progressively low δ13 C and δ15 N values over time for both muscle and fin tissues. The δ13 C turnover rates were similar for both tissues (56 and 61 days), whereas the δ15 N turnover rates differed between fin and muscle tissue in both diets (diet 1 = 4 and 130 days, and diet 2 = 72 and 300 days, respectively). The DTDFs were similar for both tissues in diet 1 (Δ13 C: -3.96 to -2.62‰, Δ15 N: 1.98 to 2.61‰) and diet 2 (Δ13 C: 4.05 to 5.24‰, Δ15 N: 8.45 to 9.69‰). CONCLUSIONS These results suggest that fin tissue can potentially be used as an alternative for muscle tissue in food web studies with a reasonable level of error. The isotopic turnover rate and DTDFs estimates for E. anoplus, however, require consideration of diet composition because different diets may differ in their isotopic incorporation patterns.
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Affiliation(s)
- Manda J Kambikambi
- Department of Ichthyology and Fisheries Science, Rhodes University, PO Box 94, Grahamstown, 6140, South Africa
| | - Albert Chakona
- South African Institute for Aquatic Biodiversity, Private Bag 1015, Grahamstown, 6140, South Africa
| | - Wilbert T Kadye
- Department of Ichthyology and Fisheries Science, Rhodes University, PO Box 94, Grahamstown, 6140, South Africa
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21
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Quispe R, Yohannes E, Gahr M. Seasonality at the equator: isotope signatures and hormonal correlates of molt phenology in a non-migratory Amazonian songbird. Front Zool 2018; 15:39. [PMID: 30386404 PMCID: PMC6205779 DOI: 10.1186/s12983-018-0284-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 09/25/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Birds, across their annual cycle, progress through sequences of life-history stages such as reproduction and molt. The mechanisms that control annual avian itineraries involve endocrine responses triggered by seasonal environmental factors, including changes in resource availability and/or photoperiod. However, at equatorial latitudes birds are exposed to different degrees of seasonality, and the mechanisms underlying phenology of birds near the equator remain less explored. We studied the silver-beaked tanager, an endemic Amazonian songbird, from an equatorial lowland population. Remarkably, in this species, song behavior has been shown to be seasonally aligned to minimal changes in day length near the equator. Here, we aimed to further explore the phenology of silver-beaked tanagers by assessing shifts of food sources utilization as potential ultimate factors. We measured triple isotopic tracers of carbon (δ13C), nitrogen (δ15N) and sulphur (δ34S) in blood and feathers of birds throughout a whole year. In addition, we assessed the degree of seasonality in the molting activity, in relation to circulating levels of corticosterone, as well as to testosterone as a proxy of the reproductive condition of males. RESULTS There was important seasonal variation of δ34S values in relation to rainfall patterns and changes in estuarine water composition. Despite the seasonal rainfall, we found no substantial variation in the foraging ecology of birds over seasons. This was accompanied by uniform levels of corticosterone throughout the year, probably associated with the absence of drastic seasonal resource shortages. Even so, silver-beaked tanagers showed a marked seasonal molting schedule, which was related to variation in the circulating levels of both corticosterone and testosterone. CONCLUSIONS These findings suggest that foraging niche is not life history stage-dependent in silver-beaked tanagers, and highlight rainfall as an important environmental cue for bird phenology. Our stable isotope results encourage further studies addressing the influence of estuarine water dynamics on bird timing. In addition, the results suggest a primary role of steroid hormones in regulating seasonal life history stages under the absence of a marked photoperiod. Contrary to what might be expected for a tropical songbird, our physiological data in silver-beaked tanagers do not support reproduction-molt overlapping.
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Affiliation(s)
- Rene Quispe
- Department of Behavioural Neurobiology, Max Planck Institute for Ornithology, Eberhard-Gwinner-Strasse, Seewiesen, 82319 Germany
- Present address: Departamento Biología Marina, Facultad Ciencias del Mar, Universidad Católica del Norte, Coquimbo, Chile
| | - Elizabeth Yohannes
- Stable Isotope Lab, Limnological Institute, University of Constance, Konstanz, Germany
| | - Manfred Gahr
- Department of Behavioural Neurobiology, Max Planck Institute for Ornithology, Eberhard-Gwinner-Strasse, Seewiesen, 82319 Germany
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22
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Amino acid isotope discrimination factors for a carnivore: physiological insights from leopard sharks and their diet. Oecologia 2018; 188:977-989. [DOI: 10.1007/s00442-018-4276-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 10/14/2018] [Indexed: 11/26/2022]
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23
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Nuche‐Pascual MT, Lazo JP, Ruiz‐Cooley RI, Herzka SZ. Amino acid-specific δ 15N trophic enrichment factors in fish fed with formulated diets varying in protein quantity and quality. Ecol Evol 2018; 8:9192-9217. [PMID: 30377494 PMCID: PMC6194260 DOI: 10.1002/ece3.4295] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 05/07/2018] [Accepted: 05/20/2018] [Indexed: 11/10/2022] Open
Abstract
Compound-specific isotope analysis (CSIA) of amino acids (AAs) in consumer tissues is a developing technique with wide-ranging applications for identifying nitrogen (N) sources and estimating animal trophic level. Controlled experiments are essential for determining which dietary conditions influence variability in N stable isotopes (δ15N) trophic enrichment factors in bulk tissue (TEFbulk) and AAs (TEFAA). To date, however, studies have not independently evaluated the effect of protein quantity and quality (digestibility) on TEFs, complicating the application of AA-δ15N values for estimating trophic levels. We conducted a 98-d feeding experiment using five formulated isoenergetic feeds prepared with a high-quality protein source to evaluate the effect of protein quantity and quality on TEFs of liver and muscle tissues of juvenile Pacific yellowtail (Seriola lalandi), a carnivorous fish species. We decreased protein digestibility using well-established protocols that do not change AA profiles. Growth rates were higher in diets with higher protein content, and isotopic equilibrium was reached for both fish tissues and all treatments. Protein quantity and quality influenced isotope discrimination depending on tissue type and AA. In liver tissue, bulk TEFs showed a limited but significant relationship with protein quality, but did not differ with protein quantity or quality in muscle. None of the pre-established source AAs (Lys, Met, Phe, and Gly) TEFs varied significantly with protein quantity or quality in liver tissue. However, in muscle tissue, TEFPhe increased significantly with protein content and decreased in response to reduced digestibility, indicating it may not serve as proxy for baseline isotopic values used to calculate trophic level. Among trophic AAs, TEFLeu decreased significantly with increasing protein quantity in liver tissue, while both Leu and Ile TEFs decreased with lower protein digestibility in muscle tissue. Our results indicate that CSIA-AA in liver tissue provides more robust source and trophic AA-δ15N values than in muscle.
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Affiliation(s)
- M. Teresa Nuche‐Pascual
- Departamento de Oceanografía BiológicaCentro de Investigación Científica y de Educación Superior de Ensenada (CICESE)EnsenadaMéxico
| | | | | | - Sharon Z. Herzka
- Departamento de Oceanografía BiológicaCentro de Investigación Científica y de Educación Superior de Ensenada (CICESE)EnsenadaMéxico
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24
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Deacy WW, Erlenbach JA, Leacock WB, Stanford JA, Robbins CT, Armstrong JB. Phenological tracking associated with increased salmon consumption by brown bears. Sci Rep 2018; 8:11008. [PMID: 30030526 PMCID: PMC6054687 DOI: 10.1038/s41598-018-29425-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 07/05/2018] [Indexed: 11/21/2022] Open
Abstract
There is growing interest in the ecological significance of phenological diversity, particularly in how spatially variable resource phenologies (i.e. resource waves) prolong foraging opportunities for mobile consumers. While there is accumulating evidence of consumers moving across landscapes to surf resource waves, there is little data quantifying how phenological tracking influences resource consumption due to the challenge of documenting all the components of this ecological phenomenon (i.e., phenological variation, consumer movement, resource consumption, and consumer fitness). We examined the space use of GPS collared female brown bears to quantify the exploitation of a salmon resource wave by individual bears. We then estimated salmon consumption levels in the same individuals using stable isotope and mercury analyses of hair. We found strong positive relationships between time spent on salmon streams and percent salmon in assimilated diets (R2 = 0.70) and salmon mass consumed (R2 = 0.49). Salmon abundance varied 2.5-fold between study years, yet accounting for salmon abundance did not improve salmon consumption models. Resource abundance generally is viewed as the key variable controlling consumption levels and food web dynamics. However, our results suggest that in intact watersheds of coastal Alaska with abundant salmon runs, interannual variation in salmon abundance likely has less effect on salmon consumption than individual variation in bear foraging behavior. The results complement previous work to demonstrate the importance of phenological variation on bear foraging behavior and fitness.
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Affiliation(s)
- William W Deacy
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR, USA. .,Flathead Lake Biological Station, University of Montana, Missoula, MT, USA.
| | - Joy A Erlenbach
- School of the Environment, Washington State University, Pullman, WA, USA
| | - William B Leacock
- Kodiak National Wildlife Refuge, United States Fish and Wildlife Service, Kodiak, AK, USA
| | - Jack A Stanford
- Flathead Lake Biological Station, University of Montana, Missoula, MT, USA
| | - Charles T Robbins
- School of the Environment, Washington State University, Pullman, WA, USA.,School of Biological Sciences, Washington State University, Pullman, WA, USA
| | - Jonathan B Armstrong
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR, USA
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25
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Villamarín F, Jardine TD, Bunn SE, Marioni B, Magnusson WE. Body size is more important than diet in determining stable-isotope estimates of trophic position in crocodilians. Sci Rep 2018; 8:2020. [PMID: 29386654 PMCID: PMC5792559 DOI: 10.1038/s41598-018-19918-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 01/04/2018] [Indexed: 11/25/2022] Open
Abstract
The trophic position of a top predator, synonymous with food-chain length, is one of the most fundamental attributes of ecosystems. Stable isotope ratios of nitrogen (δ15N) have been used to estimate trophic position of organisms due to the predictable enrichment of 15N in consumer tissues relative to their diet. Previous studies in crocodilians have found upward ontogenetic shifts in their 'trophic position'. However, such increases are not expected from what is known about crocodilian diets because ontogenetic shifts in diet relate to taxonomic categories of prey rather than shifts to prey from higher trophic levels. When we analysed dietary information from the literature on the four Amazonian crocodilians, ontogenetic shifts in dietary-based trophic position (TPdiet) were minimal, and differed from those estimated using δ15N data (TPSIA). Thus, ontogenetic shifts in TPSIA may result not only from dietary assimilation but also from trophic discrimination factors (TDF or Δ 15N) associated with body size. Using a unique TDF value to estimate trophic position of crocodilians of all sizes might obscure conclusions about ontogenetic shifts in trophic position. Our findings may change the way that researchers estimate trophic position of organisms that show orders of magnitude differences in size across their life span.
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Affiliation(s)
- Francisco Villamarín
- Coordenação de Pesquisas em Biodiversidade, Instituto Nacional de Pesquisas da Amazônia - INPA, Manaus, Brazil.
- Universidad Regional Amazónica - Ikiam, Tena, Ecuador.
| | - Timothy D Jardine
- School of Environment and Sustainability, University of Saskatchewan, Saskatoon, Canada
| | - Stuart E Bunn
- Australian Rivers Institute, Griffith University, Brisbane, Australia
| | - Boris Marioni
- Programa de Pós-Graduação em Biologia de Água Doce e Pesca Interior - INPA, Manaus, Brazil
| | - William E Magnusson
- Coordenação de Pesquisas em Biodiversidade, Instituto Nacional de Pesquisas da Amazônia - INPA, Manaus, Brazil
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26
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Corcellas C, Andreu A, Máñez M, Sergio F, Hiraldo F, Eljarrat E, Barceló D. Pyrethroid insecticides in wild bird eggs from a World Heritage Listed Park: A case study in Doñana National Park (Spain). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 228:321-330. [PMID: 28551562 DOI: 10.1016/j.envpol.2017.05.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 04/20/2017] [Accepted: 05/14/2017] [Indexed: 06/07/2023]
Abstract
Recent studies demonstrated that the common pyrethroid insecticides are present in aquatic biota tissues. In this study, 123 samples of unhatched eggs of 16 wild bird species collected from 2010 to 2012 in Doñana National and Natural Park were analysed to determine 13 pyrethroids. This study represents the first time that pyrethroids are detected in tissues of terrestrial biota, 93% of these samples being positive to those pollutants. Levels of total pyrethroids ranged from not detected to 324 ng g-1 lw. The samples were characterized by stable isotope analysis. Species with diets based on anthropogenic food showed higher levels of pyrethroids and lower values of δ15N. Finally, we characterized the isomers of pyrethroids and discerned some isomeric- and enantiomeric-specific accumulations. In particular, tetramethrin and cyhalothrin showed an enantiomeric-selective accumulation of one enantiomer, highlighting the need to assess toxicological effects of each enantiomer separately to be able to make a correct risk assessment of pyrethroids in birds.
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Affiliation(s)
- Cayo Corcellas
- Water and Soil Quality Research Group, Dep. of Environmental Chemistry (IDAEA-CSIC), Barcelona, Spain
| | - Ana Andreu
- Natural Processes Monitoring Team, Estación Biológica de Doñana (EBD-CSIC), c/Américo Vespucio s/n, 41092 Seville, Spain
| | - Manuel Máñez
- Natural Processes Monitoring Team, Estación Biológica de Doñana (EBD-CSIC), c/Américo Vespucio s/n, 41092 Seville, Spain
| | - Fabrizio Sergio
- Department of Applied Biology, Doñana Biological Station (EBD-CSIC), Seville, Spain
| | - Fernando Hiraldo
- Department of Applied Biology, Doñana Biological Station (EBD-CSIC), Seville, Spain
| | - Ethel Eljarrat
- Water and Soil Quality Research Group, Dep. of Environmental Chemistry (IDAEA-CSIC), Barcelona, Spain.
| | - Damià Barceló
- Water and Soil Quality Research Group, Dep. of Environmental Chemistry (IDAEA-CSIC), Barcelona, Spain; Catalan Institute for Water Research (ICRA), Girona, Spain
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Vansomeren LL, Barboza PS, Gustine DD, Syndonia Bret-Harte M. Variation in δ 15 N and δ 13 C values of forages for Arctic caribou: effects of location, phenology and simulated digestion. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2017; 31:813-820. [PMID: 28263443 DOI: 10.1002/rcm.7849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 02/28/2017] [Accepted: 03/01/2017] [Indexed: 06/06/2023]
Abstract
RATIONALE The use of stable isotopes for dietary estimates of wildlife assumes that there are consistent differences in isotopic ratios among diet items, and that the differences in these ratios between the diet item and the animal tissues (i.e., fractionation) are predictable. However, variation in isotopic ratios and fractionation of δ13 C and δ15 N values among locations, seasons, and forages are poorly described for arctic herbivores especially migratory species such as caribou (Rangifer tarandus). METHODS We measured the δ13 C and δ15 N values of seven species of forage growing along a 200-km transect through the range of the Central Arctic caribou herd on the North Slope of Alaska over 2 years. We compared forages available at the beginning (May; n = 175) and the end (n = 157) of the growing season (September). Purified enzymes were used to measure N digestibility and to assess isotopic fractionation in response to nutrient digestibility during simulated digestion. RESULTS Values for δ13 C declined by 1.38 ‰ with increasing latitude across the transect, and increased by 0.44 ‰ from the beginning to the end of the season. The range of values for δ15 N was greater than that for δ13 C (13.29 vs 5.60 ‰). Differences in values for δ13 C between graminoids (Eriophorum and Carex spp.) and shrubs (Betula and Salix spp.) were small but δ15 N values distinguished graminoids (1.87 ± 1.02 ‰) from shrubs (-2.87 ± 2.93 ‰) consistently across season and latitude. However, undigested residues of forages were enriched in 15 N when the digestibility of N was less than 0.67. CONCLUSIONS Although δ15 N values can distinguish plant groups in the diet of arctic herbivores, variation in the digestibility of dietary items may need to be considered in applying fractionation values for 15 N to caribou and other herbivores that select highly digestible items (e.g. forbs) as well as heavily defended plants (e.g. woody browse). Published in 2017. This article is a U.S. Government work and is in the public domain in the USA.
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Affiliation(s)
- Lindsay L Vansomeren
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, 99775-7000, USA
| | - Perry S Barboza
- Institute of Arctic Biology, Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, 99775-7000, USA
| | - David D Gustine
- U.S. Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, AK, 99508, USA
| | - M Syndonia Bret-Harte
- Institute of Arctic Biology, Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, 99775-7000, USA
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Selecting the best stable isotope mixing model to estimate grizzly bear diets in the Greater Yellowstone Ecosystem. PLoS One 2017; 12:e0174903. [PMID: 28493929 PMCID: PMC5426898 DOI: 10.1371/journal.pone.0174903] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 03/17/2017] [Indexed: 11/19/2022] Open
Abstract
Past research indicates that whitebark pine seeds are a critical food source for Threatened grizzly bears (Ursus arctos) in the Greater Yellowstone Ecosystem (GYE). In recent decades, whitebark pine forests have declined markedly due to pine beetle infestation, invasive blister rust, and landscape-level fires. To date, no study has reliably estimated the contribution of whitebark pine seeds to the diets of grizzlies through time. We used stable isotope ratios (expressed as δ13C, δ15N, and δ34S values) measured in grizzly bear hair and their major food sources to estimate the diets of grizzlies sampled in Cooke City Basin, Montana. We found that stable isotope mixing models that included different combinations of stable isotope values for bears and their foods generated similar proportional dietary contributions. Estimates generated by our top model suggest that whitebark pine seeds (35±10%) and other plant foods (56±10%) were more important than meat (9±8%) to grizzly bears sampled in the study area. Stable isotope values measured in bear hair collected elsewhere in the GYE and North America support our conclusions about plant-based foraging. We recommend that researchers consider model selection when estimating the diets of animals using stable isotope mixing models. We also urge researchers to use the new statistical framework described here to estimate the dietary responses of grizzlies to declines in whitebark pine seeds and other important food sources through time in the GYE (e.g., cutthroat trout), as such information could be useful in predicting how the population will adapt to future environmental change.
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Fuller BT, Petzke KJ. The dietary protein paradox and threonine 15 N-depletion: Pyridoxal-5'-phosphate enzyme activity as a mechanism for the δ 15 N trophic level effect. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2017; 31:705-718. [PMID: 28181729 DOI: 10.1002/rcm.7835] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 02/03/2017] [Accepted: 02/04/2017] [Indexed: 06/06/2023]
Abstract
RATIONALE Nitrogen stable isotope ratios (δ15 N values) are used to reconstruct dietary patterns, but the biochemical mechanism(s) responsible for the diet to tissue trophic level effect and its variability are not fully understood. Here δ15 N amino acid (AA) values and physiological measurements (nitrogen intake, plasma albumin concentrations, liver-reduced glutathione concentrations and leucine oxidation rates) are used to investigate increased dietary protein consumption and oxidative stress (vitamin E deficiency) in rat total plasma protein. METHODS Using gas chromatography/combustion/isotope ratio mass spectrometry, the δ15 N values from N-pivaloyl-i-propyl esters of 15 AAs are reported for rats (n = 40) fed casein-based diets with: adequate protein (AP, 13.8%; n = 10), medium protein (MP, 25.7%; n = 10), high protein (HP, 51.3%; n = 10) or HP without vitamin E (HP-E; n = 10) for 18 weeks. RESULTS Between the HP and AP groups, the δ15 NAA values of threonine (-4.0‰), serine (+1.4‰) and glycine (+1.2‰) display the largest differences and show significant correlations with: nitrogen intake, plasma albumin concentrations, liver-reduced glutathione concentrations and leucine oxidation rates. This indicates increased AA catabolism by the dietary induction of shared common metabolic pathways involving the enzymes threonine ammonia-lyase (EC 4.3.1.19), serine hydroxymethyltransferase (EC 2.1.2.1) and the glycine cleavage system (EC 2.1.2.10). The δ15 NAA values of the HP-E and HP groups were not found to be significantly different. CONCLUSIONS The 15 N-depleted results of threonine are linked to increased activity of threonine ammonia-lyase, and show potential as a possible biomarker for protein intake and/or gluconeogenesis. We hypothesize that the inverse nitrogen equilibrium isotope effects of Schiff base formation, between AAs and pyridoxal-5'-phosphate cofactor enzymes, play a key role in the bioaccumulation and depletion of 15 N in the biomolecules of living organisms and contributes to the variability in the nitrogen trophic level effect. Copyright © 2017 John Wiley & Sons, Ltd.
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Affiliation(s)
- Benjamin T Fuller
- Department of Archaeology and Anthropology, University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, 100049, China
| | - Klaus J Petzke
- Department of Physiology of Energy Metabolism, German Institute of Human Nutrition in Potsdam-Rehbruecke (DIfE), Arthur-Scheunert-Allee 114-116, D-14558, Nuthetal, Germany
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Zeichner SS, Colman AS, Koch PL, Polo-Silva C, Galván-Magaña F, Kim SL. Discrimination Factors and Incorporation Rates for Organic Matrix in Shark Teeth Based on a Captive Feeding Study. Physiol Biochem Zool 2017; 90:257-272. [DOI: 10.1086/689192] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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The influence of sulfur and hair growth on stable isotope diet estimates for grizzly bears. PLoS One 2017; 12:e0172194. [PMID: 28248995 PMCID: PMC5332026 DOI: 10.1371/journal.pone.0172194] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 02/01/2017] [Indexed: 11/19/2022] Open
Abstract
Stable isotope ratios of grizzly bear (Ursus arctos) guard hair collected from bears on the lower Stikine River, British Columbia (BC) were analyzed to: 1) test whether measuring δ34S values improved the precision of the salmon (Oncorhynchus spp.) diet fraction estimate relative to δ15N as is conventionally done, 2) investigate whether measuring δ34S values improves the separation of diet contributions of moose (Alces alces), marmot (Marmota caligata), and mountain goat (Oreamnos americanus) and, 3) examine the relationship between collection date and length of hair and stable isotope values. Variation in isotope signatures among hair samples from the same bear and year were not trivial. The addition of δ34S values to mixing models used to estimate diet fractions generated small improvement in the precision of salmon and terrestrial prey diet fractions. Although the δ34S value for salmon is precise and appears general among species and areas, sulfur ratios were strongly correlated with nitrogen ratios and therefore added little new information to the mixing model regarding the consumption of salmon. Mean δ34S values for the three terrestrial herbivores of interest were similar and imprecise, so these data also added little new information to the mixing model. The addition of sulfur data did confirm that at least some bears in this system ate marmots during summer and fall. We show that there are bears with short hair that assimilate >20% salmon in their diet and bears with longer hair that eat no salmon living within a few kilometers of one another in a coastal ecosystem. Grizzly bears are thought to re-grow hair between June and October however our analysis of sectioned hair suggested at least some hairs begin growing in July or August, not June and, that hair of wild bears may grow faster than observed in captive bears. Our hair samples may have been from the year of sampling or the previous year because samples were collected in summer when bears were growing new hair. The salmon diet fraction increased with later hair collection dates, as expected if samples were from the year of sampling because salmon began to arrive in mid-summer. Bears that ate salmon had shorter hair and δ15N and δ34S values declined with hair length, also suggesting some hair samples were grown the year of sampling. To be sure to capture an entire hair growth period, samples must be collected in late fall. Early spring samples are also likely to be from the previous year but the date when hair begins to grow appears to vary. Choosing the longest hair available should increase the chance the hair was grown during the previous year and, maximize the period for which diet is measured.
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Tsutaya T, Fujimori Y, Hayashi M, Yoneda M, Miyabe-Nishiwaki T. Carbon and nitrogen stable isotopic offsets between diet and hair/feces in captive chimpanzees. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2017; 31:59-67. [PMID: 27717069 DOI: 10.1002/rcm.7760] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Revised: 10/04/2016] [Accepted: 10/04/2016] [Indexed: 06/06/2023]
Abstract
RATIONALE Estimation of the stable isotopic offsets between tissue and diet is important for dietary reconstructions. Although stable isotopic studies of chimpanzees (Pan troglodytes) are increasing, the isotopic offsets in chimpanzees have never been studied. In this study, the carbon and nitrogen stable isotopic offset values in hair and feces were measured for 13 captive chimpanzees for the first time. METHODS All consumed food items and quantities were recorded for each individual for 1 week. Food samples were typically collected three times, hair was collected 3 weeks after the experimental week, and feces were collected ad libitum during the experimental week. The stable carbon and nitrogen isotope ratios were measured using elemental analyzer-isotope ratio mass spectrometry (EA-IRMS). RESULTS As the results of Monte Carlo analysis, the estimated carbon and nitrogen offsets between the hair and diet were +3.0 to +3.9‰ and +2.8 to +3.7‰, respectively, for the 95% confidence intervals (CIs). The 95% CIs of the carbon and nitrogen offset values between the feces and diet were -1.6 to 0.0‰ and +1.2 to +2.7‰, respectively. CONCLUSIONS These offset values are generally consistent with those of the other primate species reported in previous studies. However, potential variations in the offset values due to dietary and physiological factors should be studied in detail in the future. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Takumi Tsutaya
- Graduate School of Science, Kyoto University, Kyoto, Kyoto, 606-8502, Japan
| | - Yui Fujimori
- Japan Monkey Centre, Inuyama, Aichi, 484-8506, Japan
| | - Misato Hayashi
- Primate Research Institute, Kyoto University, Inuyama, Aichi, 484-0081, Japan
| | - Minoru Yoneda
- The University Museum, The University of Tokyo, Bunkyo, Tokyo, 113-0033, Japan
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McMahon KW, McCarthy MD. Embracing variability in amino acid δ
15
N fractionation: mechanisms, implications, and applications for trophic ecology. Ecosphere 2016. [DOI: 10.1002/ecs2.1511] [Citation(s) in RCA: 182] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Kelton W. McMahon
- Institute of Marine SciencesUniversity of California Santa Cruz California 95064 USA
| | - Matthew D. McCarthy
- Ocean Sciences DepartmentUniversity of California Santa Cruz California 95064 USA
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Elliott KH, Elliott JE. Origin of Sulfur in Diet Drives Spatial and Temporal Mercury Trends in Seabird Eggs From Pacific Canada 1968-2015. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:13380-13386. [PMID: 27993060 DOI: 10.1021/acs.est.6b05458] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Mercury (Hg) is a neurotoxin that can be particularly harmful to top predators because it biomagnifies through the food web. Due to variation in the food web structure, variation in Hg exposure in predators may represent variation in diet rather than Hg availability. We measured Hg in eggs from six seabird species (N = 537) over 47 years. In contrast to expectation, storm-petrels feeding partially on invertebrates had the highest Hg burden while herons feeding on large fish had the lowest Hg burden. A multiple regression showed that Hg correlated with δ34S (R2 = 0.86) rather than trophic level (δ15N of "trophic" amino acids). Sulfate-rich environments (high δ34S) have sulfate-reducing bacteria that produce methylmercury. Variation in Hg within and among seabirds near the top of the food web was associated with variation in δ34S at the base of the food web more so than trophic position within the food web. Hg levels in seabirds only changed over time for those species where δ34S also varied in tandem; after accounting for diet (δ34S), there was no variation in Hg levels. Variation in Hg in seabirds across space and time was associated with the origin of sulfur in the diet.
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Affiliation(s)
- Kyle H Elliott
- Department of Natural Resource Sciences, McGill University , Ste Anne-de-Bellevue Quebec, Canada H9X 3 V9
| | - John E Elliott
- Science & Technology Branch, Environment Canada , Delta British Columbia, Canada V4K 3N2
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Camin F, Bontempo L, Perini M, Piasentier E. Stable Isotope Ratio Analysis for Assessing the Authenticity of Food of Animal Origin. Compr Rev Food Sci Food Saf 2016; 15:868-877. [PMID: 33401802 DOI: 10.1111/1541-4337.12219] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 06/09/2016] [Accepted: 06/10/2016] [Indexed: 12/01/2022]
Abstract
The main elemental constituents (H, C, N, O, and S) of bio-organic material have different stable isotopes (2 H, 1 H; 13 C,12 C; 15 N,14 N; 18 O,17 O,16 O; 36 S, 34 S, 33 S, and 32 S). Isotopic ratios can be measured precisely and accurately using dedicated analytical techniques such as isotope ratio mass spectrometry (IRMS). Analysis of these ratios shows potential for assessing the authenticity of food of animal origin. In this review, IRMS analysis of food of animal origin and variability factors related to stable isotope ratios in animals are described. The study also lists examples of application of stable isotope ratio analysis to meat, dairy products, fish, and shellfish and emphasizes the strengths and weaknesses of the technique. Geographical, climatic, pedological, geological, botanical, and agricultural factors affect the stable isotope ratios (SIR) of bio-elements, and SIR variations are ultimately incorporated into animal tissue through eating, drinking, breathing, and exchange with the environment, being recorded in the resulting foods. SIR analysis was capable of determining geographical origin, animal diet, and the production system (such as organic/conventional or wild/farmed) for pork, beef, lamb, poultry, milk, butter, cheese, fish, and shellfish. In the case of the hard PDO (protected designations of origin) cheeses Grana Padano and Parmigiano Reggiano it is also used in real-life situations to assess the authenticity of grated and shredded cheese on the market.
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Affiliation(s)
- Federica Camin
- Fondazione Edmund Mach (FEM), Via E. Mach 1, I-38010, San Michele all'Adige, Italy
| | - Luana Bontempo
- Fondazione Edmund Mach (FEM), Via E. Mach 1, I-38010, San Michele all'Adige, Italy
| | - Matteo Perini
- Fondazione Edmund Mach (FEM), Via E. Mach 1, I-38010, San Michele all'Adige, Italy
| | - Edi Piasentier
- Dept. of Agricultural, Food, Environmental and Animal Sciences, Univ. of Udine, Via Sondrio 2A, 33100, Udine, Italy
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Beltran RS, Peterson SH, McHuron EA, Reichmuth C, Hückstädt LA, Costa DP. Seals and sea lions are what they eat, plus what? Determination of trophic discrimination factors for seven pinniped species. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2016; 30:1115-1122. [PMID: 27060839 PMCID: PMC4830913 DOI: 10.1002/rcm.7539] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 01/14/2016] [Accepted: 02/14/2016] [Indexed: 06/05/2023]
Abstract
RATIONALE Mixing models are a common method for quantifying the contribution of prey sources to the diet of an individual using stable isotope analysis; however, these models rely upon a known trophic discrimination factor (hereafter, TDF) that results from fractionation between prey and animal tissues. Quantifying TDFs in captive animals is ideal, because diet is controlled and the proportional contributions and isotopic values of all prey items are known. METHODS To calculate TDFs for the Hawaiian monk seal, northern elephant seal, bearded seal, ringed seal, spotted seal, harbor seal, and California sea lion, we obtained whiskers, serum, plasma, red blood cells, and prey items from nine captive individuals. We obtained δ(13) C and δ(15) N values using continuous-flow isotope-ratio mass spectrometry. The average δ(13) C and δ(15) N values from bulk and lipid-corrected prey from the diet were subtracted from the δ(13) C and δ(15) N values of each blood and whisker sample to calculate tissue-specific TDFs for each individual (∆(13) C or ∆(15) N). RESULTS The ∆(13) C values ranged from +1.7 to +3.2‰ (bulk prey) and from +0.8 to +1.9‰ (lipid-corrected prey) for the various blood components, and from +3.9 to +4.6‰ (bulk prey) or +2.6 to +3.9‰ (lipid-corrected prey) for whiskers. The ∆(15) N values ranged from +2.2 to +4.3‰ for blood components and from +2.6 to +4.0‰ for whiskers. The TDFs tended to group by tissue, with whiskers having greater ∆(13) C values than blood components. In contrast, the ∆(15) N values were greater in serum and plasma than in red blood cells and whiskers. CONCLUSIONS By providing the first TDF values for five seal species (family Phocidae) and one otariid species (family Otariidae), our study facilitates more accurate mixing models for these species. These values are particularly important for critically endangered Hawaiian monk seals and the three Arctic seal species (bearded, ringed, and spotted) that are faced with a rapidly changing environment.
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Affiliation(s)
- Roxanne S. Beltran
- University of California, Santa Cruz, Department of Ecology & Evolutionary Biology, Santa Cruz, CA 95060, USA
| | - Sarah H. Peterson
- University of California, Santa Cruz, Department of Ecology & Evolutionary Biology, Santa Cruz, CA 95060, USA
| | - Elizabeth A. McHuron
- University of California, Santa Cruz, Department of Ecology & Evolutionary Biology, Santa Cruz, CA 95060, USA
| | - Colleen Reichmuth
- Institute of Marine Sciences, Long Marine Laboratory, Santa Cruz, CA 95060, USA
| | - Luis A. Hückstädt
- University of California, Santa Cruz, Department of Ecology & Evolutionary Biology, Santa Cruz, CA 95060, USA
| | - Daniel P. Costa
- University of California, Santa Cruz, Department of Ecology & Evolutionary Biology, Santa Cruz, CA 95060, USA
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Hernández-Arciga U, Herrera M. LG, Morales-Malacara JB. Tracking host use by bat ectoparasites with stable isotope analysis. CAN J ZOOL 2016. [DOI: 10.1139/cjz-2015-0246] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We used C and N stable isotopes of nectarivorous bats and their ectoparasites to determine the extent to which parasites depend on the host individual for food. The difference in stable isotope values between parasites and host tissues (Δ13C and Δ15N) was used as a proxy of host use. First, we tested the hypothesis that movement among individual Mexican long-tongued bats (Choeronycteris mexicana Tschudi, 1844) is more likely to occur in winged flies than in mites as indicated by higher host–parasite isotopic Euclidian distance (ED). Second, we tested the hypothesis that ectoparasite species in two coexisting bat species representing the C3 (Geoffroy’s tailless bat, Anoura geoffroyi Gray, 1838) and the CAM (lesser long-nosed bat, Leptonycteris yerbabuenae Martínez and Villa-R., 1940) food chains were monoxenous as indicated by their isotopic values. We also examined Δ13C and Δ15N of individual parasites in relation to 13C and 15N reference enrichment factors as an indication of host switching. In general, flies in C. mexicana had higher ED and wider ranges of individual Δ13C and Δ15N than mites, suggesting that host switching occurred to a larger extent. Most ectoparasites species collected in both coexisting bats were monoxenous, but one fly species appears to be oligoxenous. Individual Δ13C and Δ15N values varied widely in these parasite species, suggesting movements within species hosts.
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Affiliation(s)
- Ulalume Hernández-Arciga
- Posgrado en Ciencias Biológicas, Instituto de Biología, Universidad Nacional Autónoma de México, Apartado Postal 70-153, México D.F. 04510, México
| | - L. Gerardo Herrera M.
- Estación de Biología Chamela, Instituto de Biología, Universidad Nacional Autónoma de México, Apartado Postal 21, San Patricio, JAL, 48980, México
| | - Juan B. Morales-Malacara
- Unidad Multidisciplinaria de Docencia e Investigación, Facultad de Ciencias, Universidad Nacional Autónoma de México, Campus Juriquilla, Boulevard Juriquilla 3001, Querétaro, QRO, 76230, México
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Rode KD, Stricker CA, Erlenbach J, Robbins CT, Cherry SG, Newsome SD, Cutting A, Jensen S, Stenhouse G, Brooks M, Hash A, Nicassio N. Isotopic Incorporation and the Effects of Fasting and Dietary Lipid Content on Isotopic Discrimination in Large Carnivorous Mammals. Physiol Biochem Zool 2016; 89:182-97. [DOI: 10.1086/686490] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Naito YI, Chikaraishi Y, Drucker DG, Ohkouchi N, Semal P, Wißing C, Bocherens H. Ecological niche of Neanderthals from Spy Cave revealed by nitrogen isotopes of individual amino acids in collagen. J Hum Evol 2016; 93:82-90. [DOI: 10.1016/j.jhevol.2016.01.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 11/07/2015] [Accepted: 01/31/2016] [Indexed: 10/22/2022]
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Busst GMA, Britton JR. High variability in stable isotope diet-tissue discrimination factors of two omnivorous freshwater fishes in controlled ex situ conditions. ACTA ACUST UNITED AC 2016; 219:1060-8. [PMID: 26896544 DOI: 10.1242/jeb.137380] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 01/27/2016] [Indexed: 11/20/2022]
Abstract
Diet-tissue discrimination factors (Δ(13)C and Δ(15)N) are influenced by variables including the tissues being analysed and the taxon of the consumer and its prey. Whilst differences in Δ(13)C and Δ(15)N are apparent between herbivorous and piscivorous fishes, there is less known for omnivorous fishes that consume plant and animal material. Here, the omnivorous cyprinid fishes Barbus barbus and Squalius cephalus were held in tank aquaria and exposed to three diets that varied in their constituents (plant based to fishmeal based) and protein content (13% to 45%). After 100 days and isotopic replacement in fish tissues to 98%, samples of the food items, and dorsal muscle, fin tissue and scales were analysed for δ(13)C and δ(15)N. For both species and all diets, muscle was always enriched in δ(15)N and depleted in δ(13)C compared with fin tissue and scales. Across the different diets, Δ(13)C ranged between 2.0‰ and 5.6‰ and Δ(15)N ranged between 2.0‰ and 6.9‰. The diet based on plant material (20% protein) always resulted in the highest discrimination factors for each tissue, whilst the diet based on fishmeal (45% protein) consistently resulted in the lowest. The discrimination factors produced by non-fish diets were comparatively high compared with values in the literature, but were consistent with general patterns for some herbivorous fishes. These outputs suggest that the diet-tissue discrimination factors of omnivorous fishes will vary considerably between animal and plant prey, and these specific differences need consideration in predictions of their diet composition and trophic position.
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Affiliation(s)
- Georgina M A Busst
- Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole BH12 5BB, UK
| | - J Robert Britton
- Department of Life and Environmental Sciences, Faculty of Science and Technology, Bournemouth University, Poole BH12 5BB, UK
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McLaren AAD, Crawshaw GJ, Patterson BR. Carbon and nitrogen discrimination factors of wolves and accuracy of diet inferences using stable isotope analysis. WILDLIFE SOC B 2015. [DOI: 10.1002/wsb.599] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Ashley A. D. McLaren
- Ontario Ministry of Natural Resources and Forestry; Wildlife Research and Monitoring Section, Trent University, DNA Building; 2140 East Bank Drive Peterborough ON K9J 7B8 Canada
| | | | - Brent R. Patterson
- Ontario Ministry of Natural Resources and Forestry; Wildlife Research and Monitoring Section, Trent University, DNA Building; 2140 East Bank Drive Peterborough ON K9J 7B8 Canada
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van Gils JA, Ahmedou Salem MV. Validating the Incorporation of 13C and 15N in a Shorebird That Consumes an Isotopically Distinct Chemosymbiotic Bivalve. PLoS One 2015; 10:e0140221. [PMID: 26458005 PMCID: PMC4601768 DOI: 10.1371/journal.pone.0140221] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2015] [Accepted: 09/23/2015] [Indexed: 11/18/2022] Open
Abstract
The wealth of field studies using stable isotopes to make inferences about animal diets require controlled validation experiments to make proper interpretations. Despite several pleas in the literature for such experiments, validation studies are still lagging behind, notably in consumers dwelling in chemosynthesis-based ecosystems. In this paper we present such a validation experiment for the incorporation of 13C and 15N in the blood plasma of a medium-sized shorebird, the red knot (Calidris canutus canutus), consuming a chemosymbiotic lucinid bivalve (Loripes lucinalis). Because this bivalve forms a symbiosis with chemoautotrophic sulphide-oxidizing bacteria living inside its gill, the bivalve is isotopically distinct from 'normal' bivalves whose food has a photosynthetic basis. Here we experimentally tested the hypothesis that isotope discrimination and incorporation dynamics are different when consuming such chemosynthesis-based prey. The experiment showed that neither the isotopic discrimination factor, nor isotopic turnover time, differed between birds consuming the chemosymbiotic lucinid and a control group consuming a photosynthesis-based bivalve. This was true for 13C as well as for 15N. However, in both groups the 15N discrimination factor was much higher than expected, which probably had to do with the birds losing body mass over the course of the experiment.
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Affiliation(s)
- Jan A. van Gils
- NIOZ Royal Netherlands Institute for Sea Research, 1790 AB Den Burg, The Netherlands
- * E-mail:
| | - Mohamed Vall Ahmedou Salem
- EBIOME Ecobiologie Marine et Environnement, Département de Biologie, Université des Sciences, de Technologie et de Médecine, B.P. 880, Nouakchott, Mauritania
- Laboratoire de Biologie Appliquée et Pathologie, Département de Biologie, Faculté des Science, B.P. 2121, Tetouan, Morocco
- Parc National du Banc d’Arguin, B.P. 5355, Nouakchott, Mauritania
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43
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Yurkowski DJ, Ferguson SH, Semeniuk CAD, Brown TM, Muir DCG, Fisk AT. Spatial and temporal variation of an ice-adapted predator's feeding ecology in a changing Arctic marine ecosystem. Oecologia 2015. [PMID: 26210748 DOI: 10.1007/s00442-015-3384-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Spatial and temporal variation can confound interpretations of relationships within and between species in terms of diet composition, niche size, and trophic position (TP). The cause of dietary variation within species is commonly an ontogenetic niche shift, which is a key dynamic influencing community structure. We quantified spatial and temporal variations in ringed seal (Pusa hispida) diet, niche size, and TP during ontogeny across the Arctic-a rapidly changing ecosystem. Stable carbon and nitrogen isotope analysis was performed on 558 liver and 630 muscle samples from ringed seals and on likely prey species from five locations ranging from the High to the Low Arctic. A modest ontogenetic diet shift occurred, with adult ringed seals consuming more forage fish (approximately 80 versus 60 %) and having a higher TP than subadults, which generally decreased with latitude. However, the degree of shift varied spatially, with adults in the High Arctic presenting a more restricted niche size and consuming more Arctic cod (Boreogadus saida) than subadults (87 versus 44 %) and adults at the lowest latitude (29 %). The TPs of adult and subadult ringed seals generally decreased with latitude (4.7-3.3), which was mainly driven by greater complexity in trophic structure within the zooplankton communities. Adult isotopic niche size increased over time, likely due to the recent circumpolar increases in subarctic forage fish distribution and abundance. Given the spatial and temporal variability in ringed seal foraging ecology, ringed seals exhibit dietary plasticity as a species, suggesting adaptability in terms of their diet to climate change.
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Affiliation(s)
- David J Yurkowski
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON, N9B 3P4, Canada.
| | - Steven H Ferguson
- Freshwater Institute, Fisheries and Oceans Canada, Winnipeg, MB, R3T 2N6, Canada.
| | - Christina A D Semeniuk
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON, N9B 3P4, Canada.
| | - Tanya M Brown
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 3P6, Canada.
| | - Derek C G Muir
- Aquatic Ecosystem Protection Research Division, Environment Canada, Burlington, ON, L7R 4A6, Canada.
| | - Aaron T Fisk
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON, N9B 3P4, Canada.
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Naito YI, Morita A, Natsuhara K, Tadokoro K, Baba J, Odani S, Tomitsuka E, Igai K, Tsutaya T, Yoneda M, Greenhill AR, Horwood PF, Soli KW, Phuanukoonnon S, Siba PM, Umezaki M. Association of protein intakes and variation of diet-scalp hair nitrogen isotopic discrimination factor in Papua New Guinea highlanders. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2015; 158:359-70. [DOI: 10.1002/ajpa.22798] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 06/09/2015] [Accepted: 06/09/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Yuichi I. Naito
- Department of Integrated Biosciences; Graduate School of Frontier Sciences, The University of Tokyo; Kashiwanoha 5-1-5 Kashiwa Chiba 277-8562 Japan
| | - Ayako Morita
- Department of Human Ecology; Graduate School of Medicine, The University of Tokyo; 7-3-1 Hongo Bunkyo Tokyo 113-0033 Japan
- Tokyo Medical and Dental University; Yushima 1-5-45 Bunkyo-ku Tokyo 113-8519 Japan
| | - Kazumi Natsuhara
- The Japanese Red Cross Akita College of Nursing; Nawashirosawa 17-3, Saruta, Kamikitate Akita Akita 010-1493 Japan
| | - Kiyoshi Tadokoro
- Department of Human Ecology; Graduate School of Medicine, The University of Tokyo; 7-3-1 Hongo Bunkyo Tokyo 113-0033 Japan
| | - Jun Baba
- The Research Institute for Languages and Cultures of Asia and Africa, Tokyo University of Foreign Studies; 3-11-1 Asahi-cho Fuchu Tokyo 183-8534 Japan
| | - Shingo Odani
- Faculty of Letters, Chiba University; 1-33 Yayoicho, Inage Chiba 263-8522 Japan
| | - Eriko Tomitsuka
- Department of Human Ecology; Graduate School of Medicine, The University of Tokyo; 7-3-1 Hongo Bunkyo Tokyo 113-0033 Japan
| | - Katsura Igai
- Graduate School of Biomedical Science, Nagasaki University; 1-12-4 Sakamoto Nagasaki 852-8523 Japan
| | - Takumi Tsutaya
- Department of Integrated Biosciences; Graduate School of Frontier Sciences, The University of Tokyo; Kashiwanoha 5-1-5 Kashiwa Chiba 277-8562 Japan
| | - Minoru Yoneda
- Department of Integrated Biosciences; Graduate School of Frontier Sciences, The University of Tokyo; Kashiwanoha 5-1-5 Kashiwa Chiba 277-8562 Japan
- The University Museum, The University of Tokyo; Hongo 7-3-1 Bunkyo Tokyo 113-0033 Japan
| | - Andrew R. Greenhill
- Papua New Guinea Institute of Medical Research, PO Box 60, Goroka, Eastern Highlands Province 441; Papua New Guinea
- Federation University; Gippsland Campus Northways Road, Churchill Victoria 3842 Australia
| | - Paul F. Horwood
- Papua New Guinea Institute of Medical Research, PO Box 60, Goroka, Eastern Highlands Province 441; Papua New Guinea
| | - Kevin W. Soli
- Papua New Guinea Institute of Medical Research, PO Box 60, Goroka, Eastern Highlands Province 441; Papua New Guinea
| | - Suparat Phuanukoonnon
- Papua New Guinea Institute of Medical Research, PO Box 60, Goroka, Eastern Highlands Province 441; Papua New Guinea
| | - Peter M. Siba
- Papua New Guinea Institute of Medical Research, PO Box 60, Goroka, Eastern Highlands Province 441; Papua New Guinea
| | - Masahiro Umezaki
- Department of Human Ecology; Graduate School of Medicine, The University of Tokyo; 7-3-1 Hongo Bunkyo Tokyo 113-0033 Japan
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Cloyed CS, Newsome SD, Eason PK. Trophic Discrimination Factors and Incorporation Rates of Carbon- and Nitrogen-Stable Isotopes in Adult Green Frogs, Lithobates clamitans. Physiol Biochem Zool 2015; 88:576-85. [PMID: 26658253 DOI: 10.1086/682576] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Stable isotope analysis is an increasingly useful ecological tool, but its accuracy depends on quantifying the tissue-specific trophic discrimination factors (TDFs) and isotopic incorporation rates for focal taxa. Despite the technique's ubiquity, most laboratory experiments determining TDFs and incorporation rates have focused on birds, mammals, and fish; we know little about terrestrial ectotherms, and amphibians in particular are understudied. In this study we used two controlled feeding experiments to determine carbon (δ(13)C) and nitrogen (δ(15)N) isotope TDFs for skin, whole blood, and bone collagen and incorporation rates for skin and whole blood in adult green frogs, Lithobates clamitans. The mean (±SD) TDFs for δ(13)C were 0.1‰ (±0.4‰) for skin, 0.5‰ (±0.5‰) for whole blood, and 1.6‰ (0.6‰) for bone collagen. The mean (±SD) TDFs for δ(15)N were 2.3‰ (±0.5‰) for skin, 2.3‰ (±0.4‰) for whole blood, and 3.1‰ (±0.6‰) for bone collagen. A combination of different isotopic incorporation models was best supported by our data. Carbon in skin was the only tissue in which incorporation was best explained by two compartments, which had half-lives of 89 and 8 d. The half-life of carbon in whole blood was 69 d. Half-lives for nitrogen were 75 d for skin and 71 d for whole blood. Our results help fill a taxonomic gap in our knowledge of stable isotope dynamics and provide ecologists with a method to measure anuran diets.
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Affiliation(s)
- Carl S Cloyed
- Department of Biology, University of Louisville, Louisville, Kentucky 40292; 2Department of Biology, University of New Mexico, Albuquerque, New Mexico 87131
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deVries MS, del Rio CM, Tunstall TS, Dawson TE. Isotopic incorporation rates and discrimination factors in mantis shrimp crustaceans. PLoS One 2015; 10:e0122334. [PMID: 25835953 PMCID: PMC4383329 DOI: 10.1371/journal.pone.0122334] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Accepted: 02/10/2015] [Indexed: 11/19/2022] Open
Abstract
Stable isotope analysis has provided insights into the trophic ecology of a wide diversity of animals. Knowledge about isotopic incorporation rates and isotopic discrimination between the consumer and its diet for different tissue types is essential for interpreting stable isotope data, but these parameters remain understudied in many animal taxa and particularly in aquatic invertebrates. We performed a 292-day diet shift experiment on 92 individuals of the predatory mantis shrimp, Neogonodactylus bredini, to quantify carbon and nitrogen incorporation rates and isotope discrimination factors in muscle and hemolymph tissues. Average isotopic discrimination factors between mantis shrimp muscle and the new diet were 3.0 ± 0.6 ‰ and 0.9 ± 0.3 ‰ for carbon and nitrogen, respectively, which is contrary to what is seen in many other animals (e.g. C and N discrimination is generally 0–1 ‰ and 3–4 ‰, respectively). Surprisingly, the average residence time of nitrogen in hemolymph (28.9 ± 8.3 days) was over 8 times longer than that of carbon (3.4 ± 1.4 days). In muscle, the average residence times of carbon and nitrogen were of the same magnitude (89.3 ± 44.4 and 72.8 ± 18.8 days, respectively). We compared the mantis shrimps’ incorporation rates, along with rates from four other invertebrate taxa from the literature, to those predicted by an allometric equation relating carbon incorporation rate to body mass that was developed for teleost fishes and sharks. The rate of carbon incorporation into muscle was consistent with rates predicted by this equation. Our findings provide new insight into isotopic discrimination factors and incorporation rates in invertebrates with the former showing a different trend than what is commonly observed in other animals.
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Affiliation(s)
- Maya S. deVries
- Department of Integrative Biology, University of California, Berkeley, California, United States of America
- * E-mail:
| | - Carlos Martínez del Rio
- Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, United States of America
| | - Tate S. Tunstall
- Department of Integrative Biology, University of California, Berkeley, California, United States of America
| | - Todd E. Dawson
- Department of Integrative Biology, University of California, Berkeley, California, United States of America
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Remien CH. Modeling the dynamics of stable isotope tissue-diet enrichment. J Theor Biol 2014; 367:14-20. [PMID: 25457228 DOI: 10.1016/j.jtbi.2014.11.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 11/15/2014] [Accepted: 11/19/2014] [Indexed: 10/24/2022]
Abstract
Reconstructions of dietary composition and trophic level from stable isotope measurements of animal tissue rely on predictable offsets of stable isotope ratios from diet to tissue. Physiological processes associated with metabolism shape tissue stable isotope ratios, and as such the spacing between stable isotope ratios of diet and tissue may be influenced by processes such as growth, nutritional stress, and disease. Here, we develop a model of incorporation stable isotopes in diet to tissues by coupling stable isotope dynamics to a model of macronutrient energy metabolism. We use the model to explore the effect of changes in dietary intake, both composition and amount, and in energy expenditure, on body mass and carbon and nitrogen stable isotope ratios of tissue.
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48
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Phillips DL, Inger R, Bearhop S, Jackson AL, Moore JW, Parnell AC, Semmens BX, Ward EJ. Best practices for use of stable isotope mixing models in food-web studies. CAN J ZOOL 2014. [DOI: 10.1139/cjz-2014-0127] [Citation(s) in RCA: 691] [Impact Index Per Article: 69.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Stable isotope mixing models are increasingly used to quantify consumer diets, but may be misused and misinterpreted. We address major challenges to their effective application. Mixing models have increased rapidly in sophistication. Current models estimate probability distributions of source contributions, have user-friendly interfaces, and incorporate complexities such as variability in isotope signatures, discrimination factors, hierarchical variance structure, covariates, and concentration dependence. For proper implementation of mixing models, we offer the following suggestions. First, mixing models can only be as good as the study and data. Studies should have clear questions, be informed by knowledge of the system, and have strong sampling designs to effectively characterize isotope variability of consumers and resources on proper spatio-temporal scales. Second, studies should use models appropriate for the question and recognize their assumptions and limitations. Decisions about source grouping or incorporation of concentration dependence can influence results. Third, studies should be careful about interpretation of model outputs. Mixing models generally estimate proportions of assimilated resources with substantial uncertainty distributions. Last, common sense, such as graphing data before analyzing, is essential to maximize usefulness of these tools. We hope these suggestions for effective implementation of stable isotope mixing models will aid continued development and application of this field.
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Affiliation(s)
- Donald L. Phillips
- U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Western Ecology Division, 200 SW 35th Street, Corvallis, OR 97330, USA
| | - Richard Inger
- Environment and Sustainability Institute, School of Biosciences, University of Exeter, Cornwall Campus, Penryn, Cornwall, TR10 9EZ, UK
| | - Stuart Bearhop
- Environment and Sustainability Institute, School of Biosciences, University of Exeter, Cornwall Campus, Penryn, Cornwall, TR10 9EZ, UK
| | - Andrew L. Jackson
- Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland
| | - Jonathan W. Moore
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Andrew C. Parnell
- School of Mathematical Sciences (Statistics), Complex and Adaptive Systems Laboratory, University College Dublin, Dublin 4, Ireland
| | - Brice X. Semmens
- Scripps Institution of Oceanography, University of California – San Diego, San Diego, CA 92093, USA
| | - Eric J. Ward
- Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA 98112, USA
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49
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Isotopic Discrimination Factors (Δ13C and Δ15N) between Tissues and Diet of the Broad-Snouted Caiman (Caiman latirostris). J HERPETOL 2014. [DOI: 10.1670/12-274] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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50
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Macharia AN, Cerling TE, Jorgensen MJ, Kaplan JR. The Hair-Diet13C and15N Fractionation inChlorocebus aethiops sabaeusBased on a Control Diet Study. ANN ZOOL FENN 2014. [DOI: 10.5735/086.051.0208] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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