Tidal exchange, bivalve grazing, and patterns of primary production in Willapa Bay, Washington, USA

被引:71
作者
Banas, N. S.
Hickey, B. M.
Newton, J. A.
Ruesink, J. L.
机构
[1] Univ Washington, Sch Oceanog, Seattle, WA 98195 USA
[2] Univ Washington, Appl Phys Lab, Seattle, WA 98195 USA
[3] Univ Washington, Dept Biol, Seattle, WA USA
关键词
estuaries; primary production; bivalves; tidal circulation; biophysical interactions; Willapa Bay;
D O I
10.3354/meps341123
中图分类号
Q14 [生态学(生物生态学)];
学科分类号
071012 ; 0713 ;
摘要
Willapa Bay, Washington, USA, is a shallow, coastal-plain, upwelling-influenced estuary where Pacific oysters Crassostrea gigas are intensively cultivated. CTD transect data show that in the long-term average over the May to September growing season, Willapa Bay is a sink for oceanic phytoplankton, not a net exporter: as the tidal circulation stirs ocean water into the estuary, chlorophyll concentration declines by 30 to 60% relative to a hypothetical dilution of the ocean end-member. A 3D circulation model (General Estuarine Transport Model, GETM) was modified to include a phytoplankton-like tracer subject to variable intertidal benthic grazing rates. The grazing rate that best reproduces the along-estuary phytoplankton biomass profile agrees, within confidence limits, with an estimate of cultivated-oyster filtration from literature values. Oysters and other intertidal benthic grazers may thus be the primary cause of the net loss of phytoplankton within the estuary in summer. These grazers appear to be within a small factor of their carrying capacity: as bay-total filtration capacity is increased in the model, the chlorophyll intrusion shortens and food intake per individual grazer declines. Nevertheless, only 8 to 15% of the net tidal supply of oceanic phytoplankton is consumed within the estuary. Even in this well-flushed system, the small-scale structure of tidal transport-rather than total oceanic supply-controls overall food availability for the benthos.
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页码:123 / 139
页数:17
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