Document Type
Thesis
Abstract
Recent 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.
Publication Date
12-17-2000
Recommended Citation
Abromaitis, Grace Elizabeth, "A retrospective assessment of primary productivity on the Bering and Chukchi Sea shelves using stable isotope ratios in seabirds" (2000). Marine Biology. 29.
https://ualaska.researchcommons.org/uaf_marinebio_facpubs/29
Handle
http://hdl.handle.net/11122/4944