CS29 Phytoplankton & Primary Production
Date: Monday, June 10, 2002
Time: 4:30:00 PM
Location: Oak Bay
 
RoelkeDL, Texas A&M University, College Station, TX, USA, droelke@tamu.edu
 
DIVERGENCE OF NEARBY TRAJECTORIES IN THE SEASONAL PHYTOPLANKTON SUCCESSION OF LAKE SOMERVILLE, TX
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Divergence of nearby trajectories, a telltale sign of chaotic behavior in nonlinear systems, was observed in an 11-year phytoplankton record from a semi-tropical, polymictic lake, where seasonal disturbances are relatively small. Cluster analysis at the Genus level of phytoplankton community composition revealed strong groupings of the diatom Melosira sp. during winter months and the euglenoid Trachelomonas sp. in the summer. When Trachelomonas sp. did not dominate the summer assemblage a cyanophyte did. Discriminant analysis of the physical and water quality parameters spanning this period showed a strong distinction between the environment and the composition of the phytoplankton community. Divergence of nearby trajectories was apparent with scrutiny of the cyanophyte group, i.e., while environmental variables associated with cyanophyte dominance were very similar the dominant Genera of cyanophyte was never the same. Theories emerging from the field of chaos and nonlinear dynamics should be considered when investigating processes influencing the phytoplankton biodiversity in this lake.