Dynamics of anoxia
Abstract A simple steady-state, one-dimensional advective diffusive model of the ocean's coupled carbon, oxygen and phosphorous system is developed. The model is an extension of Wyrtki's (1962) model of the oxygen distribution. The occurrence of anoxia requires two conditions: (1) sufficiently high productivity, and (2) sufficiently low oxygen concentration in the bottom water. It is shown that anoxic layers are most likely to occur fairly high in the water column. Anoxic events may be associated with timesof vigorous thermohaline circulation in contrast to stagnation arguments often invoked. The model results are used to interpret both modern and ancient oceanic anoxic events.