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ROLE OF OCEANIC AND RIVERINE SOURCES IN NUTRIENT AND PHYTOPLANKTON DYNAMICS IN YAQUINA BAY, OREGON
Citation:
Brown, C A. AND R J. Ozretich. ROLE OF OCEANIC AND RIVERINE SOURCES IN NUTRIENT AND PHYTOPLANKTON DYNAMICS IN YAQUINA BAY, OREGON. Presented at Estuarine Research Federation meeting, Seattle, WA, September 14-18, 2003.
Description:
There is evidence that coastal ecosystems are experiencing environmental problems due to excess nutrients. The numerous sources, forms, and pathways of nutrients make it difficult to determine the effect of increases in anthropogenic loading. This is particularly evident in Pacific northwest estuaries where there is a seasonal change in the dominant nutrient sources from riverine to oceanic associated with the transition from winter to summer. We used a laterally-averaged hydrodynamic and water quality model to examine the importance of oceanic and riverine sources on nutrient and phytoplankton dynamics in Yaquina Bay, Oregon. The input of phytoplankton and dissolved inorganic nutrients from the coastal ocean was estimated using daily flood tide samples during May to October, 2002. During the same interval, weekly cruises were conducted to examine the spatial distribution of nutrients, phytoplankton, and other physical parameters within the bay. During the summer of 2002, the ocean dominated the nutrient loading to the bay; however, this source was temporally variable. We used the numerical model to examine how much utilization there was of the oceanic nutrients, how much of the nutrients was exported from the system, and the role of physical processes in controlling water column productivity in the estuary.