COMPARISON OF ZYGNEMATACEAN (CHLOROPHYTA) ALGAE IN THE METAPHYTON OF 2 ACIDIC LAKES

In 1986, Plastic Lake (pH≃5.6), acidified by acidic precipitation, and L.302S (pH≃5.0), experimentally acidified by addition of H2 SO4, showed similar patterns of unattached benthic growth (metaphyton) of filamentous green algae. The mid to late summer build-up of metaphyton was extensive in both lakes, affecting nearly 100% of the lake perimeters. Distribution was negatively related to depth and bottom slope but independent of type of substratum. The areal density of metaphyton in the 0-2 depth zone of Plastic Lake was estimated to be 1.2g dry weight (dw).m-2. The productivity of metaphyton standardized by biomass was inversely related to the concentration of algae incubated. Over a common range of incubation concentrations primary production rates were similar in algae incubated. Over a common range of incubation concentrations primary production rates were similar in L.302S and Plastic Lake (≃1.6 μg C(mg dw)- 1.h-1) despite differences in the composition of the communities. -from Authors