POC and PON data were collected biweekly until April 1986, and weekly thereafter. Nutrient data were collected daily until April 1986, and about three times a week thereafter. Major ion data have always been collected weekly. Data Presentation and Analysis. All data for each parameter is presented in the Figures.
Error bars represent one standard error.
All statistical analysis were done on log transformed data. We attribute this to phytoplankton and zooplankton biomass loss from the water column. Their disappearance suggests lack of seasonal selectivity in removing plankton from the water column. The increase in POC concentrations since 1991 suggest at least partial recovery of plankton populations. D. polymorpha may have reached a peak and are starting to decline.