Detrended Correspondence Analysis of Phytoplankton Abundance and Distribution in Sandusky Bay and Lake Erie

Abstract

The purpose of this study was to determine if phytoplankton communities in Sandusky Bay were distinct from those of Lake Erie. Samples were taken from 11 sites along a 50 km transect extending from the lower reaches of the Sandusky River, through Sandusky Bay and into the western basin of Lake Erie to identify factors correlated with identifiable patterns in distribution and abundance of summer phytoplankton. Detrended correspondence analysis (DCA), an ordination technique used to describe patterns in complex data sets, arranged the sample sites along an ordination axis that explained 76% of the variation in the phytoplankton abundance data matrix, and produced the following sequence of ordination axis scores: Sandusky Bay→ Lake Erie→ Sandusky River. DCA axis I scores strongly correlated with total phosphorus, soluble reactive phosphorus, algal phosphatase activity, dissolved oxygen, conductivity, turbidity, and alkalinity, but not chloride concentration, suggesting that phytoplankton abundance and distribution were related to phosphorus availability and not simply due to the passive movement of water along the transect. Bacterial abundance correlated with DCA axis I, suggesting that phytoplankton-bacterial interactions may be important in understanding distributional patterns of Sandusky Bay phytoplankton.