Reply to comment by Roberta M. Hotinski, Lee R. Kump, and Karen L. Bice on “Could the Late Permian deep ocean have been anoxic?”.

(Zhang, R and Follows, MJ and Marshall, J), PALEOCEANOGRAPHY, vol. 18, no. 4, 2003.

Abstract

Two recent studies [Hotinski et al., 2001; Zhang et al., 2001] have modeled and discussed Late Permian ocean circulation and oxygenation. These studies have reached significantly different conclusions. Zhang et al. [2001] find that a ‘‘thermal mode’’ ocean circulation driven by cooling in polar latitudes is unlikely to support deep-sea anoxia, but a ‘‘haline mode’’ ocean circulation, a shallow overturning cell driven by enhanced evaporation from the subtropics, perhaps could lead to global-scale deep-sea anoxia. Hotinski et al. [2001], using a different model, find that a ‘‘thermal mode’’ ocean circulation with a high equator-to-pole gradient gives well-oxygenated Permian deep water, while a ‘‘thermal mode’’ ocean circulation with a very low equator-to-pole gradient leads to global deep-sea anoxia. This discrepancy prompted a comment by Hotinski et al. [2002].

doi = 10.1029/2002PA000851