Use of Modified Diurnal Curves for the Measurement of Metabolism in Standing Water.

A modification of diurnal oxygen curves is described, whereby community metabolism can be easily estimated from a succession of twice‐nightly points. The method can be adapted to stratified limnetic waters by using suitable sampling techniques. Results of a study using the method are given for a small, fertile Georgia farm pond. Gross photosynthesis averaged 6.0 g O2 m−2 day−1, ranging from 1.0 to 14 g O2 m−2 day−1. The approximate net loss of oxygen due to diffusion was 101.1 g O2 m−2 yr−1, less than 5% of total gross photosynthesis.