Diurnal variation in dissolved oxygen measurements during late winter ice-covered period, Sleeper's River, Vermont

Dissolved oxygen (DO), a critical element in riverine systems, is required to support aquatic life and maintain good water quality. Previous research has documented the occurrence of oxygen depressions in ice-covered rivers that coincide with ice cover formation (Schallock and Lotspeich, 1974; Schreier et al., 1980;Whitfield and McNaughton, 1986). These oxygen sags have been attributed to lack of reaeration because of the ice cover, oxidation of organic material, and inputs of oxygen-depleted groundwater. Diurnal variations in dissolved oxygen an key to understanding the oxygen balance processes of a stream, and previous studies provide only limited data in this regard. The present study incorporates continuous, high-temporal-resolution sub-ice water quality data and photosynthetically active radiation (PAR) data for a gaged site in the Sleeper's River Research Watershed, Vermont. The first winter's observations, collected during late winter through spring breakup, are presented here. These data describe in detail the in-stream water quality environment during spring breakup and reveal a pronounced diurnal cycling of dissolved oxygen in the period just prior to breakup that appears to be the result of biological processes.