JPR Advance Access originally published online on September 9, 2009
Journal of Plankton Research 2009 31(11):1385-1390; doi:10.1093/plankt/fbp075
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Thin layer formation during runaway stratification in the tidally dynamic San Francisco Estuary
1 Ocean Earth and Atmospheric Sciences, Old Dominion University, Norfolk, VA, USA 2 School of Earth and Environmental Sciences, Washington State University, Vancouver, WA, USA
* CORRESPONDING AUTHOR: abochdan{at}odu.edu
Received on December 8, 2008; accepted on August 2, 2009
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Abstract |
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During the course of a year, we repeatedly collected high-resolution vertical fluorometer data timed to coincide with a specific state during the tidal cycle. The time (end of the ebb during neap tide) and the location (a deep channel half-way between the Golden Gate and the point of tidally averaged bottom salinity of 2 psu) were chosen with the goal to observe runaway stratification. We consistently found at least one pronounced chlorophyll peak in the water column; however, the vertical location of these peaks varied within three types including surface, bottom and subsurface maxima. Our results showed that heterogeneity of chlorophyll in the water column and thin layer formation do occur in systems that are characterized by high tidal flow speeds thus resulting in patchy prey fields for zooplankton that migrate in tidal cycles through the water column. Using these chlorophyll profiles, approximate calculations suggested that only during the spring phytoplankton bloom did all layers of the water column provide sufficient food for maximum egg production of the San Francisco Estuary copepod Acartia sp.
Corresponding editor: Roger Harris