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BIOTIC AND ABIOTIC FACTORS INFLUENCING SUCCESSION OF MAJOR PHYTOPLANKTON TAXA IN AN URBAN ESTUARY IN SOUTHEAST VIRGINIA, USA

Estuaries are dynamic ecosystems, characterized by high productivity and lower biodiversity. As the dominant primary producers, estuarine algal populations fluctuate throughout the year in relation to abiotic and biotic variables. Under certain bloom conditions, the phytoplankton community may negatively impact the environment through hypoxia, high turbidity and effects on trophic structure. In order to develop a better understanding of phytoplankton bloom cues and resulting conditions in an estuarine ecosystem, tri-weekly monitoring was conducted during peak bloom months from May to September 2014, 2015, and 2016 on Knitting Mill Creek, an urban tidal tributary of the Elizabeth River in Norfolk, Virginia. Water quality parameters (temp, salinity, pH, DO, Chla) were measured and water samples were collected for microscopic analyses. Dinoflagellates were the dominant phyla, contributing an average of >90% of algal biomass. A succession of four dinoflagellates in particular, Akashiwo sanguinea, Scrippsiella trochoidea, Gymnodinium spp. and Cochlodinium polykrikoides were most significant, with densities reaching 2.4-7.2 x 10 3 cells ml -1. Correlation analyses indicate that these populations fluctuate in the system in relation to multiple abiotic factors in addition to biotic factors that satisfy mixotrophic characteristics including changes in populations of small cryptomonads and microphytoflagellates. Ranges in environmental variability and community composition highlight a need for higher frequency monitoring, and potential implications to harmful algal bloom management for beaches, hatcheries and fisheries.

Authors

Millman, W. S., Department of Biological Sciences, Old Dominion University, USA, Wmill024@odu.edu

Wiesner, K. M., Department of Biological Sciences, Old Dominion University, USA, kwies002@odu.edu

Gibala-Smith, L. A., Department of Biological Sciences, Old Dominion University, USA, lgibalas@odu.edu

Sandusky, C., Department of Biological Sciences, Old Dominion University, USA, sand001@odu.edu

Egerton, T. A., Department of Biological Sciences, Old Dominion University, USA, todd.egerton@vdh.virginia.gov

Details

Poster presentation

Session #:021
Date: 03/03/2017
Time: 11:00 - 12:00
Location: Poster/Exhibit Hall

Presentation is given by student: Yes

PosterID: 221