Temporal and spatial trends in marine carbon isotopes in the Arctic Ocean and implications for food web studies

de la Vega, Camille, Jeffreys, Rachel ORCID: 0000-0001-6114-2334, Tuerena, Robyn, Ganeshram, Raja and Mahaffey, Claire ORCID: 0000-0002-4215-7271
(2019) Temporal and spatial trends in marine carbon isotopes in the Arctic Ocean and implications for food web studies. Global Change Biology, 25 (12). 4116 - 4130.

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The Arctic is undergoing unprecedented environmental change. Rapid warming, decline in sea ice extent, increase in riverine input, ocean acidification and changes in primary productivity are creating a crucible for multiple concurrent environmental stressors, with unknown consequences for the entire arctic ecosystem. Here, we synthesised 30 years of data on the stable carbon isotope (δ13 C) signatures in dissolved inorganic carbon (δ13 C-DIC; 1977 to 2014), marine and riverine particulate organic carbon (δ13 C-POC; 1986 to 2013) and tissues of marine mammals in the Arctic. δ13 C values in consumers can change as a result of environmentally driven variation in the δ13 C values at the base of the food web or alteration in the trophic structure, thus providing a method to assess the sensitivity of food webs to environmental change. Our synthesis reveals a spatially heterogeneous and temporally evolving δ13 C baseline, with spatial gradients in the δ13 C-POC values between arctic shelves and arctic basins likely driven by differences in productivity and riverine and coastal influence. We report a decline in δ13 C-DIC values (-0.011 ‰ y-1 ) in the Arctic, reflecting increasing anthropogenic carbon dioxide (CO2 ) in the Arctic Ocean (i.e. Suess effect), which is larger than predicted. The larger decline in δ13 C-POC values and δ13 C in arctic marine mammals reflects the anthropogenic CO2 signal as well as the influence of a changing arctic environment. Combining the influence of changing sea ice conditions and isotopic fractionation by phytoplankton, we explain the decadal decline in δ13 C-POC values in the Arctic Ocean and partially explain the δ13 C values in marine mammals with consideration of time-varying integration of δ13 C values. The response of the arctic ecosystem to ongoing environmental change is stronger than we would predict theoretically, which has tremendous implications for the study of food webs in the rapidly changing Arctic Ocean.

Item Type: Article
Depositing User: Symplectic Admin
Date Deposited: 03 Oct 2019 15:32
Last Modified: 05 Oct 2022 22:33
DOI: 10.1111/gcb.14832
Open Access URL: https://doi.org/10.1111/gcb.14832
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3056921