Standing crops and primary productivity of the epipelon of two small ponds in North Somerset, U. K.

The primary productivity and the standing crop of the epipelic algal communities in two small ponds of contrasting nutrient status were measured over a 2 year period. Standing crops reflected the richer nutrient status of the eutrophic Abbot's Pond compared with the oligotrophic Priddy Pool as did the productivity results when the same depth category in both ponds was examined. Production resulted from an interrelationship among light intensity, standing crop size and other variable environmental factors in both pools, however light in Abbot's Pond appeared to be the most important factor in limiting standing crop size and production in the deeper depth categories.