Samples were obtained and preserved in situ through the winter season using automated time series samplers. The samplers were composed of an array of syringes suspended at a series of depths on an in situ mooring. Each syringe was hydraulically connected to a manifold and linked to a gear pump. A floating piston in each syringe was hydraulically driven to draw water at prescribed time intervals and introduce Lugol's solution (KI, I and acetic acid) as a preservative.
Algae were identified and enumerated with the use of a Nikon Diaphot inverted microscope under oil immersion at 1000x magnification. Subsamples were allowed to settle in chambers following the method of Utermohl. Strip counts were made with a minimum of 100 individuals of the most common taxa enumerated. Identifications were based primarily upon keys by Prescott, Tikkanen, and Seaburg et al. Cells with intact chloroplasts were counted as "live". Visibly-degraded cells were not counted. We noted qualitatively that few visibly degraded cells were found in the winter samples, which is comparable to the summer samples. Subsamples were also examined at 100x to enumerate protozoans.
In order to evaluate changes in cell volume between winter and summer, cell volumes were determined by measuring cell dimensions and approximating cell shape to geometric shape. Dimensions of 10 cells of each taxa were measured in four samples from different depths collected in April 1990. In a previous study, 100 cells of each taxa were measured to determine variance in size.
