The relationship of environmental variability to the spatial patterns of phytoplankton biomass in Lake Tahoe

Horizontal transects measuring phytoplankton biomass and temperature were made in Lake Tahoe in the nearshore epilimnion in 1976 and 1977, near the deep chlorophyll maximum in midlake in 1977, and in the deep thermocline in 1976. Variance spectra from these transects indicate that large length scale patchiness depends on large-scale habitat variability, manifested as nitrate patchiness, caused by stream inflow in the nearshore epilimnion and by differential transport processes in the deeper water. When large-scale sources of habitat variability are absent, phytoplankton spatial patterns are not dominated by large-scale patches and are consistent with a random distribution. No significant small-scale patchiness was seen under any environmental conditions.