Female Pacific walruses (Odobenus rosmarus divergens) show greater partitioning of sea ice organic carbon than males: Evidence from ice algae trophic markers
The expected reduction of ice algae with declining sea ice may prove to be detrimental to the Pacific Arctic ecosystem. Benthic organisms that rely on sea ice organic carbon (iPOC) sustain benthic predators such as the Pacific walrus ( Odobenus rosmarus divergens ). The ability to track the trophic...
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Online Access: | http://dx.doi.org/10.1371/journal.pone.0255686 https://dx.plos.org/10.1371/journal.pone.0255686 |
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crplos:10.1371/journal.pone.0255686 2024-05-19T07:36:52+00:00 Female Pacific walruses (Odobenus rosmarus divergens) show greater partitioning of sea ice organic carbon than males: Evidence from ice algae trophic markers Koch, Chelsea W. Cooper, Lee W. Woodland, Ryan J. Grebmeier, Jacqueline M. Frey, Karen E. Stimmelmayr, Raphaela Magen, Cédric Brown, Thomas A. Mancinelli, Giorgio noaa research Division of Arctic Sciences Division of Arctic Sciences Division of Arctic Sciences Division of Arctic Sciences Division of Arctic Sciences North Pacific Research Board noaa research division of arctic sciences division of arctic sciences division of arctic sciences university of maryland wylie dissertation fellowship 2021 http://dx.doi.org/10.1371/journal.pone.0255686 https://dx.plos.org/10.1371/journal.pone.0255686 en eng Public Library of Science (PLoS) http://creativecommons.org/licenses/by/4.0/ PLOS ONE volume 16, issue 8, page e0255686 ISSN 1932-6203 journal-article 2021 crplos https://doi.org/10.1371/journal.pone.0255686 2024-05-01T07:00:09Z The expected reduction of ice algae with declining sea ice may prove to be detrimental to the Pacific Arctic ecosystem. Benthic organisms that rely on sea ice organic carbon (iPOC) sustain benthic predators such as the Pacific walrus ( Odobenus rosmarus divergens ). The ability to track the trophic transfer of iPOC is critical to understanding its value in the food web, but prior methods have lacked the required source specificity. We analyzed the H-Print index, based on biomarkers of ice algae versus phytoplankton contributions to organic carbon in marine predators, in Pacific walrus livers collected in 2012, 2014 and 2016 from the Northern Bering Sea (NBS) and Chukchi Sea. We paired these measurements with stable nitrogen isotopes ( δ 15 N) to estimate trophic position. We observed differences in the contribution of iPOC in Pacific walrus diet between regions, sexes, and age classes. Specifically, the contribution of iPOC to the diet of Pacific walruses was higher in the Chukchi Sea (52%) compared to the NBS (30%). This regional difference is consistent with longer annual sea ice persistence in the Chukchi Sea. Within the NBS, the contribution of iPOC to walrus spring diet was higher in females (~45%) compared to males (~30%) for each year (p < 0.001), likely due to specific foraging behavior of females to support energetic demands associated with pregnancy and lactation. Within the Chukchi Sea, the iPOC contribution was similar between males and females, yet higher in juveniles than in adults. Despite differences in the origin of organic carbon fueling the system (sea ice versus pelagic derived carbon), the trophic position of adult female Pacific walruses was similar between the NBS and Chukchi Sea (3.2 and 3.5, respectively), supporting similar diets (i.e. clams). Given the higher quality of organic carbon from ice algae, the retreat of seasonal sea ice in recent decades may create an additional vulnerability for female and juvenile Pacific walruses and should be considered in management of the species. Article in Journal/Newspaper Arctic Bering Sea Chukchi Chukchi Sea ice algae Odobenus rosmarus Pacific Arctic Phytoplankton Sea ice walrus* PLOS PLOS ONE 16 8 e0255686 |
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language |
English |
description |
The expected reduction of ice algae with declining sea ice may prove to be detrimental to the Pacific Arctic ecosystem. Benthic organisms that rely on sea ice organic carbon (iPOC) sustain benthic predators such as the Pacific walrus ( Odobenus rosmarus divergens ). The ability to track the trophic transfer of iPOC is critical to understanding its value in the food web, but prior methods have lacked the required source specificity. We analyzed the H-Print index, based on biomarkers of ice algae versus phytoplankton contributions to organic carbon in marine predators, in Pacific walrus livers collected in 2012, 2014 and 2016 from the Northern Bering Sea (NBS) and Chukchi Sea. We paired these measurements with stable nitrogen isotopes ( δ 15 N) to estimate trophic position. We observed differences in the contribution of iPOC in Pacific walrus diet between regions, sexes, and age classes. Specifically, the contribution of iPOC to the diet of Pacific walruses was higher in the Chukchi Sea (52%) compared to the NBS (30%). This regional difference is consistent with longer annual sea ice persistence in the Chukchi Sea. Within the NBS, the contribution of iPOC to walrus spring diet was higher in females (~45%) compared to males (~30%) for each year (p < 0.001), likely due to specific foraging behavior of females to support energetic demands associated with pregnancy and lactation. Within the Chukchi Sea, the iPOC contribution was similar between males and females, yet higher in juveniles than in adults. Despite differences in the origin of organic carbon fueling the system (sea ice versus pelagic derived carbon), the trophic position of adult female Pacific walruses was similar between the NBS and Chukchi Sea (3.2 and 3.5, respectively), supporting similar diets (i.e. clams). Given the higher quality of organic carbon from ice algae, the retreat of seasonal sea ice in recent decades may create an additional vulnerability for female and juvenile Pacific walruses and should be considered in management of the species. |
author2 |
Mancinelli, Giorgio noaa research Division of Arctic Sciences Division of Arctic Sciences Division of Arctic Sciences Division of Arctic Sciences Division of Arctic Sciences North Pacific Research Board noaa research division of arctic sciences division of arctic sciences division of arctic sciences university of maryland wylie dissertation fellowship |
format |
Article in Journal/Newspaper |
author |
Koch, Chelsea W. Cooper, Lee W. Woodland, Ryan J. Grebmeier, Jacqueline M. Frey, Karen E. Stimmelmayr, Raphaela Magen, Cédric Brown, Thomas A. |
spellingShingle |
Koch, Chelsea W. Cooper, Lee W. Woodland, Ryan J. Grebmeier, Jacqueline M. Frey, Karen E. Stimmelmayr, Raphaela Magen, Cédric Brown, Thomas A. Female Pacific walruses (Odobenus rosmarus divergens) show greater partitioning of sea ice organic carbon than males: Evidence from ice algae trophic markers |
author_facet |
Koch, Chelsea W. Cooper, Lee W. Woodland, Ryan J. Grebmeier, Jacqueline M. Frey, Karen E. Stimmelmayr, Raphaela Magen, Cédric Brown, Thomas A. |
author_sort |
Koch, Chelsea W. |
title |
Female Pacific walruses (Odobenus rosmarus divergens) show greater partitioning of sea ice organic carbon than males: Evidence from ice algae trophic markers |
title_short |
Female Pacific walruses (Odobenus rosmarus divergens) show greater partitioning of sea ice organic carbon than males: Evidence from ice algae trophic markers |
title_full |
Female Pacific walruses (Odobenus rosmarus divergens) show greater partitioning of sea ice organic carbon than males: Evidence from ice algae trophic markers |
title_fullStr |
Female Pacific walruses (Odobenus rosmarus divergens) show greater partitioning of sea ice organic carbon than males: Evidence from ice algae trophic markers |
title_full_unstemmed |
Female Pacific walruses (Odobenus rosmarus divergens) show greater partitioning of sea ice organic carbon than males: Evidence from ice algae trophic markers |
title_sort |
female pacific walruses (odobenus rosmarus divergens) show greater partitioning of sea ice organic carbon than males: evidence from ice algae trophic markers |
publisher |
Public Library of Science (PLoS) |
publishDate |
2021 |
url |
http://dx.doi.org/10.1371/journal.pone.0255686 https://dx.plos.org/10.1371/journal.pone.0255686 |
genre |
Arctic Bering Sea Chukchi Chukchi Sea ice algae Odobenus rosmarus Pacific Arctic Phytoplankton Sea ice walrus* |
genre_facet |
Arctic Bering Sea Chukchi Chukchi Sea ice algae Odobenus rosmarus Pacific Arctic Phytoplankton Sea ice walrus* |
op_source |
PLOS ONE volume 16, issue 8, page e0255686 ISSN 1932-6203 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1371/journal.pone.0255686 |
container_title |
PLOS ONE |
container_volume |
16 |
container_issue |
8 |
container_start_page |
e0255686 |
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1799476017333534720 |