ALGAE OF 2 SOMERSETSHIRE POOLS - STANDING CROPS OF PHYTOPLANKTON AND EPIPELIC ALGAE AS MEASURED BY CELL NUMBERS AND CHLOROPHYLL A

Standing crops measured as cell numbers and as chlorophyll a content of phytoplankton and epipelic algal communities (those free‐living on sediment surfaces) in 2 small water bodies of contrasted nutrient status were measured for 27 months. Mean yearly crops, on an areal basis, of phytoplankton were 4–13.4 times greater than those of epipelic algae in the nutrient‐rich pool, but were only 0.65–1.8 times as great in the nutrient‐poor pool, which, however, was shallower than the rich pool. The role of cells < 5 μ, in diameter in the composition of standing crops was minor. Effects of phytoplankton in limiting growth of epipelic algae by light attenuation are shown. Compilation of available data shows a direct relationship between epipelic algal crops in various water bodies and nutrient‐status of the ambient water, similar to that already established for phytoplankton. Copyright © 1969, Wiley Blackwell. All rights reserved