SS3.06 Large Scale Change in Prominent Ecosystems
Date: Wednesday, June 12, 2002
Time: 11:00:00 AM
Location: Lecture Theatre
 
MillieDF, Florida Marine Research Institute, Fish & Wildlife Conservation Commission, St. Petersburg, FL 33701, USA, david.millie@fwc.state.fl.us
Fahnenstiel, G, L, NOAA/GLERL-Lake Michigan Field Station, Muskegon, MI 49441, USA, fahnenstiel@glerl.noaa.gov
Carrick, H, J, School of Forest Resources, Fisheries & Wildlife, Pennsylvania State University, University Park, PA 16802, USA, hjc11@psu.edu
Lohrenz, S, E, Institute of Marine Science, University of Southern Mississippi, Stennis Space Center, MS 39529, USA, slohrenz@ssc.usm.edu
Schofield, O, M, Institute of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ 08901, USA, oscar@imcs.rutgers.edu
 
LAKE MICHIGAN PHYTOPLANKTON DURING THE SPRING ISOTHERMAL PERIOD: IMPACT OF SYNOPTIC-SCALE SEDIMENT RESUSPENSION EVENTS
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The impact of episodic, sediment resuspension on phytoplankton composition, biomass, and production was evaluated during the spring isothermal period from 1998 to 2000. Increased particulate matter and decreased integral irradiance coincided with events. Total Chl a was not always spatially uniform from near- to offshore waters. No impact of resuspension on biomass accumulation was observed. However, the association of resuspension with diatom Chl and the inverse relationship between relative diatom and cryptophyte Chl corresponded with the dominance of diatoms and cryptophytes in near- and offshore waters. Species composition varied spatially during events; small, centric diatoms exhibiting meroplanktonic life histories and large, pennate diatoms considered benthic in origin were associated with events whereas diatoms and cryptophytes typically comprising phytoplankton of the annual spring bloom and of optically-clear, offshore waters were not. Integral production decreased within sediment-impacted waters; however, mean water-column production was similar between impacted near- and offshore waters with the greatest values occurring at stations influenced by tributary inflows. The photosynthetic parameters, Pmax and alpha, displayed a positive and negative correspondence with suspended particulate concentrations and mean water-column irradiance, respectively.