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Robinson AL, Elliott Smith EA, Besser AC, Newsome SD. Tissue-specific carbon isotope patterns of amino acids in southern sea otters. Oecologia 2024; 204:13-24. [PMID: 38227253 DOI: 10.1007/s00442-023-05505-8] [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: 03/04/2023] [Accepted: 12/13/2023] [Indexed: 01/17/2024]
Abstract
The measurement of stable isotope values of individual compounds, such as amino acids (AAs), has become a powerful tool in animal ecology and ecophysiology. As with any emerging technique, questions remain regarding the capabilities and limitations of this approach, including how metabolism and tissue synthesis impact the isotopic values of individual AAs and subsequent multivariate patterns. We measured carbon isotope (δ13C) values of essential (AAESS) and nonessential (AANESS) AAs in bone collagen, whisker, muscle, and liver from ten southern sea otters (Enhydra lutris nereis) that stranded in Monterey Bay, California. Sea otters in this population exhibit high degrees of individual dietary specialization, making this an excellent dataset to explore differences in AA δ13C values among tissues in a wild population. We found the δ13C values of the AANESS glutamic acid, proline, serine, and glycine and the AAESS threonine differed significantly among tissues, indicating possible isotopic discrimination during tissue synthesis. Threonine δ13C values were higher in liver relative to bone collagen and muscle, which may indicate catabolism of threonine for gluconeogenesis, an interpretation further supported by correlations between the δ13C values of threonine and its gluconeogenic products glycine and serine in liver. This intraindividual isotopic variation yielded different ecological interpretations among tissues; for 6/10 of the sea otter individuals analyzed, at least one tissue indicated reliance on a different primary producer source than the other tissues. Our results highlight the importance of gluconeogenesis in a carnivorous marine mammal and indicate that metabolic processes influence AAESS and AANESS δ13C values and multivariate AA δ13C patterns.
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Affiliation(s)
- Alana L Robinson
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA.
| | - Emma A Elliott Smith
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA
- Department of Anthropology, National Museum of Natural History, Smithsonian Institution, Washington, DC, 20560, USA
| | - Alexi C Besser
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, 85287, USA
| | - Seth D Newsome
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA
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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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Gobel N, Laufer G, González-Bergonzoni I, Soutullo Á, Arim M. Invariant and vulnerable food web components after bullfrog invasion. Biol Invasions 2022. [DOI: 10.1007/s10530-022-02956-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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Elliott Smith EA, Fox MD, Fogel ML, Newsome SD. Amino acid
δ
13
C fingerprints of nearshore marine autotrophs are consistent across broad spatiotemporal scales: an intercontinental isotopic dataset and likely biochemical drivers. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Emma A. Elliott Smith
- National Museum of Natural History Smithsonian Institution Washington DC 20560 USA
- Department of Biology University of New Mexico Albuquerque NM 87131 USA
| | - Michael D. Fox
- Red Sea Research Center Division of Biological and Environmental Science and Engineering King Abdullah University of Science and Technology Thuwal Saudi Arabia
- Woods Hole Oceanographic Institution Woods Hole MA 02543 USA
| | - Marilyn L. Fogel
- EDGE Institute University of California – Riverside Riverside CA 92521 USA
| | - Seth D. Newsome
- Department of Biology University of New Mexico Albuquerque NM 87131 USA
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Morton DN, Antonino CY, Broughton FJ, Dykman LN, Kuris AM, Lafferty KD. A food web including parasites for kelp forests of the Santa Barbara Channel, California. Sci Data 2021; 8:99. [PMID: 33833244 PMCID: PMC8032823 DOI: 10.1038/s41597-021-00880-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 02/19/2021] [Indexed: 11/28/2022] Open
Abstract
We built a high-resolution topological food web for the kelp forests of the Santa Barbara Channel, California, USA that includes parasites and significantly improves resolution compared to previous webs. The 1,098 nodes and 21,956 links in the web describe an economically, socially, and ecologically vital system. Nodes are broken into life-stages, with 549 free-living life-stages (492 species from 21 Phyla) and 549 parasitic life-stages (450 species from 10 Phyla). Links represent three kinds of trophic interactions, with 9,352 predator-prey links, 2,733 parasite-host links and 9,871 predator-parasite links. All decisions for including nodes and links are documented, and extensive metadata in the node list allows users to filter the node list to suit their research questions. The kelp-forest food web is more species-rich than any other published food web with parasites, and it has the largest proportion of parasites. Our food web may be used to predict how kelp forests may respond to change, will advance our understanding of parasites in ecosystems, and fosters development of theory that incorporates large networks.
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Affiliation(s)
- Dana N Morton
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, 93106-6150, USA.
- Marine Science Institute, University of California, Santa Barbara, CA, 93106-9610, USA.
| | - Cristiana Y Antonino
- College of Creative Studies, University of California, Santa Barbara, CA, 93106-6150, USA
| | - Farallon J Broughton
- College of Creative Studies, University of California, Santa Barbara, CA, 93106-6150, USA
| | - Lauren N Dykman
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, 93106-6150, USA
| | - Armand M Kuris
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, 93106-6150, USA
- Marine Science Institute, University of California, Santa Barbara, CA, 93106-9610, USA
| | - Kevin D Lafferty
- Western Ecological Research Center, U.S. Geological Survey, at Marine Science Institute, University of California, Santa Barbara, CA, 93106-9610, USA
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