The Dissolved Oxygen of an Upland Pond and its Inflowing Stream, at Ystumtuen, North Cardiganshire, Wales

Abstract

Weekly detns. of O2 in the water of various parts of the pond and its inflowing stream from Aug., 1940, to Oct., 1941, are compared. In the stream, which is almost entirely free from vegetation, O2 conc. changes are essentially detd. by temp. changes. In the pond, which contains vegetation. O2 conc. is essentially determined by temp. and the photo-synthetic and respiratory activities of organisms. The net effect of Equitetum and Potamogeton physiology is to reduce the dissolved O2 below the level at which it stands in their absence. O2 content in the vegetation region barely reaches that of the open water even at the period of the diurnal maximum.