Abstracts
SEARCH Open Science Meeting
October 27, 2003
Seattle, Washington, USA
Spatial Variations in Sea Ice Habitats, Marine Mammals, and Food Resources
Chadwick V. Jay1
1U.S. Geological Survey, Alaska Science Center, 1011 East Tudor Road, Anchorage, AK, 99503, USA, Phone 907-786-3856, Fax 907-786-3636, chad_jay@usgs.gov
Changes in sea ice conditions in the Bering and Chukchi Seas effect ice-inhabiting seals and walruses directly by altering the availability of suitable substrate used for resting, molting, and giving birth, and indirectly by altering pelagic and benthic production. Regional shifts in population density would be expected to vary among species because they are distributed variously among ice types and tend to partition food resources. In turn, food web dynamics may be regionally impacted by shifts in these population densities.
For example, the Pacific walrus (Odobenus rosmarus divergens) plays a prominent role in the Arctic marine ecosystem. They modify the seafloor by tilling large quantities of surficial sediment while rooting for benthic invertebrates, each year resuspending more than 19 times the annual sediment discharge of the Yukon River. While doing so, they remove as much as 3 million mt of biomass from the benthos each year, equivalent to 170 times the total annual goundfish landing in Alaska.
Walruses mainly occupy a narrow band of the ice edge in the Chukchi Sea in summer, and divergence zones and polynyas throughout the range of sea ice in the Bering Sea in winter and spring. During years of extreme northern retreat of the pack ice in the Chukchi Sea toward deeper waters of the Arctic Basin, walruses lose access to their preferred foraging areas over the shallow continental shelf near the ice front and are forced to occupy land haulouts. Similarly, during years of minimal ice extent in the Bering Sea, they lose access to southern regions of the shelf. As a result, their influence on benthic processes from foraging are likely to shift over substantial areas.
Studies that examine the persistence of various ice habitats and their significance to pelagic and benthic production and marine mammal distributions, and interactions between marine mammals and their prey should enable better predictions of the potential impacts of global warming to Arctic systems.
Abstract Categories: Changes in the Sea
Back to main abstract page
Previous Abstract | Next Abstract
| 