Aquatic Sciences Meeting, Albuquerque 2001

CS28 Phytoplankton: Distributions in Space and Time

Date: Thursday, February 15, 2001, Time: 10:30:00 AM

Location: Dona Ana

Crowder, M, E, University of Michigan-Center for Great Lakes and Aquatic Sciences, Ann Arbor, USA, mcrowder@umich.edu

Goad, L, M, University of Michigan-Center for Great Lakes and Aquatic Sciences, Ann Arbor, USA, lgoad@umich.edu

Julius, M, L, University of Michigan-Center for Great Lakes and Aquatic Sciences, Ann Arbor, USA, mjulius@umich.edu

EVALUATING NONRANDOM MIGRATION IN GREAT LAKES PHYTOPLANKTON COMMUNITIES DURING A 24-HOUR PERIOD

The classic view of phytoplankton has been that they are fairly static in the water column and do not actively move within it. This investigation examines the distribution of chlorophyll peaks over the course of the day in Lake Michigan's water column. In July 1999, measurements were taken hourly over a 24-hour period at two locations on Lake Michigan. Duplicate measurements were obtained in August 2000 for the same Lake Michigan station over a 24-hour period. Data were taken using a CTD, measuring temperature, pH, conductivity, dissolved oxygen, percent light transmittance, PAR, and fluorescence. These data demonstrate that during a 24-hour period, phytoplankton communities are slowly moving within the water column beyond the extent of currents. For each station, fluorescence peaks according to depth separate and merge over the course of a day, indicating general movement of phytoplankton. Resampling statistics can be used to demonstrate that the movement is nonrandom, and reacts in responses to environmental factors. By comparing changes in each parameter with phytoplankton movement in a series of simulations, the factors stimulating this movement can be identified.

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Aquatic Sciences Meeting, Albuquerque 2001

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