What We Are [and are not] Modeling (click here)
A simple model of the temperature-dependent biological decay of dissolved oil is embedded in an ocean climate model and used to simulate underwater plumes of dissolved and suspended oil originating from a point source in the northern Gulf of Mexico, with an upper-bound supply rate estimated from the contemporary analysis of the Deepwater Horizon blowout. The behavior of plumes at different depths is found to be determined by the combination of sheared current strength and the vertical profile of decay rate. For all plume scenarios, toxic levels of dissolved oil remain confined to the northern Gulf of Mexico, and abate within weeks after the spill stops. An estimate of oxygen consumption due to microbial oxidation of hydrocarbons suggests that a deep plume of hydrocarbons could lead to localized regions of prolonged hypoxia near the source, but only when oxidation of methane is included. [Abstract from GRL paper]...
One of greatest immediate contributors to dead sealife is anoxic water conditions in the case of underwater oil deposits due to manmade releases. This model attempts to illustrate how the characteristics of the oil and methane contribute to those conditions.
...Changing the decay rate for the oil will affect the extension of the dissolved oil plumes and the timing of oxygen draw-down, but any rate that is broadly consistent with the laboratory studies of the decay of oil in seawater will give broadly similar results. It is only when the dissolved oxygen is fully consumed that the decay rates will be dramatically slower.
Not in this study are the long term effects of the hydrocarbons themselves in creating birth defects resulting in death of sealife and slowing their recovery curve, especially endangered and threatened marine mammals.
