Spatial and temporal distribution of dissolved oxygen

Small temporal and spatial variations in the distribution of dissolved oxygen in Crater Lake, Oregon, are used to estimate the mean age of the lake’s deep water, the flux of labile organic carbon to the deep lake, and the influence of hydrothermal activity on the concentration of dissolved oxygen within the lake. An increase in the concentration of dissolved oxygen in the deep water during winter 1988-1989 indicates that 30-45 % of deep water was replaced with well-oxygenated surface water. This deep-water renewal corresponds to a mean deep water residence time of 2-4 yr. The deep-water oxygen consumption rate is 2 l-26 pmol m-3 d-l, which occurs primarily through the oxidation of organic matter and, to a lesser extent, the oxidation of reduced inorganic species that are introduced to the lake via subsurface hydrothermal springs. Dissolved oxygen is a sensitive tracer of the physical and chemical processes occurring in an aquatic system. Oxygen in excess of atmospheric saturation in the upper water column is caused by photosynthesis, in situ warm-ing of the water column by penetration of solar radiation, and air bubble injection (Jenkins and Goldman 1985