Brunell, Mark S , Litton, Gary M .
Phytoplankton diversity and population dynamics in the non-tidal to tidal transition zone of the freshwater San Joaquin River (California, U.S.A.).
As part of a larger study investigating the influence of algae on dissolved oxygen in the Stockton Deep Water Ship Channel, the phytoplankton community was characterized over a two year period (2005 – 2006) during summer and fall months. A reach of 52 km was sampled over 6 monthly periods using a Lagrangian sampling scheme. Phytoplankton in whole water preserved samples were identified, enumerated, and measured for biovolume calculations. Results show that centric diatoms and green algae dominate the phytoplankton, and that in general phytoplankton density and total biovolume decrease over the study reach as the water flows into the deeper waters of the ship channel. Diatoms dominated in the summer months of 2005 with green algae dominating in the late summer and early fall. In 2006 diatoms and green algae largely co-dominated. Zooplankton biomass (determined in another study) generally negatively correlates with phytoplankton abundance, especially in the deeper, tidally-influenced lower section of the study reach above the ship channel. There, high density of zooplankton (largely copepods and rotifers) is coincident with low algal levels. During some periods, species diversity is seen to change little over the study reach whereas in other periods it steadily decreases as water flows into the ship channel.
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1 - University of the Pacific, Biological Sciences, 3601 Pacific Avenue, Stockton, CA, 95211, USA
2 - University of the Pacific, Civil Engineering, 3601 Pacific Avenue, Stockton, CA, 95211, USA
San Joaquin River
Presentation Type: Oral Paper:Papers for Sections
Date: Monday, July 28th, 2008
Time: 10:15 AM