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dc.contributor.authorAbromaitis, Grace Elizabeth
dc.date.accessioned2015-02-12T01:37:07Z
dc.date.available2015-02-12T01:37:07Z
dc.date.issued2000-12
dc.identifier.urihttp://hdl.handle.net/11122/4944
dc.descriptionThesis (M.S.) University of Alaska Fairbanks, 2000en_US
dc.description.abstractRecent declines of marine mammal seabird populations in the Bering Sea have raised the question of whether the changes are caused by fishing pressure or a decrease in ecosystem carrying capacity. Stable carbon (¹³C⁾ and nitrogen (¹⁵N⁾ isotope ratios in Thick⁻billed Murre muscle and feathers were used as indicators of changing seasonal primary production. ¹³C values in phytoplankton vary directly with growth rates and are passed up the food web to consumers. Muscle and feather ¹³C values decreased over the period 1976-1998 suggesting a decline in Bering/Chukchi continental shelf primary production. Carbon isotope ratios in murres were correlated with bowhead whale baleen isotope ratios and to some climate indices. In contrast, ¹⁵N values in the birds showed no significant change indicating no concurrent shifts in trophic status.en_US
dc.language.isoen_USen_US
dc.titleA retrospective assessment of primary productivity on the Bering and Chukchi Sea shelves using stable isotope ratios in seabirdsen_US
dc.typeThesisen_US
dc.type.degreemsen_US
dc.identifier.departmentMarine Science and Limnology
dc.contributor.chairSchell, Donald
dc.contributor.committeeCastellini, Michael
dc.contributor.committeeSpringer, Alan
refterms.dateFOA2020-03-05T09:18:51Z


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