Journal
EARTH AND PLANETARY SCIENCE LETTERS
Volume 304, Issue 1-2, Pages 270-279Publisher
ELSEVIER
DOI: 10.1016/j.epsl.2011.02.011
Keywords
anoxia; euxinia; oceanic anoxic events; biogeochemical cycles; phosphorus cycle
Categories
Funding
- Japan Society for the Promotion of Science [20340144]
- Grants-in-Aid for Scientific Research [20340144] Funding Source: KAKEN
Ask authors/readers for more resources
Widespread black shale depositional intervals termed oceanic anoxic events (OAEs) occurred repeatedly during the Phanerozoic Eon. Here we developed a new vertical one-dimensional ocean biogeochemical cycle model that involves several chemical reactions in an oxic-anoxic-sulfidic water column. To explore the theoretical constraints for global oceanic anoxia/euxinia quantitatively and systematically, we conducted sensitivity analyses of the proposed causal mechanisms, including elevated rates of riverine phosphorus (P) input, ocean stagnation, and lowered oxygen solubility due to climate warming. We gave special attention to the vertical chemical structure of the ocean and also to the characteristic behaviors of the marine P cycle under anoxic conditions, because the relationship between the depth of anoxia and the benthic phosphorus flux could be important for the occurrence of oceanic anoxia/euxinia. Steady-state simulations indicated that (1) a decrease in ocean stagnation or oxygen solubility is not enough by itself to achieve widespread anoxia with the present reactive P river input rate, and (2) shallow water anoxia followed by massive P liberation from surface sediments can lead to widespread eutrophication and anoxia/euxinia. We conclude that elevated riverine flux of reactive P is the most important factor for triggering global anoxic events via a positive feedback loop among ocean anoxia, phosphorus regeneration, and surface biological productivity. (C) 2011 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available