Phytoplankton Cell Lysis after Water Bloom in a Eutrophic Freshwater Lake Taihu (China)

Abstract

AbstractThe phytoplankton lysis rates in the different eutrophic regions of Lake Taihu were determined based on the activities of particle and dissolved esterase, as well as the decay rate of the latter, from August 2009 to March 2010. Two peaks were observed for the chlorophyll a concentration, one in September 2009 and another in January 2010. The highest phytoplankton lysis rates observed in October were associated with the decay of the summer bloom, whereas the minimum lysis rates observed in January were associated with the winter bloom. The highest cell lysis rates in Meiliang Bay, Lake centre, and Gonghu Bay were 0.67, 0.77, and 0.68 d–1, respectively, whereas the lowest lysis rates in these regions were 0.03, 0.01, and 0.05 d–1, respectively. Water temperature showed an apparent indirect effect on lysis rate. In addition, a significant inverse relationship was observed between lysis rates and nitrate concentration in the three lake regions, which suggests that phytoplankton cell lysis is associated with changes in nitrate concentration. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)