A Double-Edged Sword: The Role of Sulfate in Anoxic Marine Phosphorus Cycling Through Earth History
- Creators
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Kipp, Michael A.
Abstract
Modern anoxic marine sediments release phosphorus (P) to seawater, driving feedbacks at multiple timescales. On sub-Myr timescales, anoxic P regeneration amplifies ocean deoxygenation; on multi-Myr timescales, it stabilizes atmospheric O₂. Some authors have extended this thinking to the Precambrian: by analogy, widespread ocean anoxia would imply extensive P regeneration from sediments. However, this neglects the role of sulfate in P regeneration. While abundant in seawater today, sulfate was scarce in the Precambrian. Here a simple model is used to isolate the role of sulfate in anoxic P cycling. The model reproduces known feedbacks driven by anoxic P regeneration in a high-sulfate world, but shows muted P regeneration in low-sulfate, anoxic sediments. The transition between "limited" and "enhanced" P regeneration is thus controlled by sulfate. As a result, sulfate is a double-edged sword wielded by the anoxic P cycle: it can amplify oxygenation or deoxygenation depending on environmental context.
Additional Information
This work was financially supported by an Agouron Institute Postdoctoral Fellowship in Geobiology. The author thanks two anonymous reviewers for comments that improved the manuscript, as well as Angelicque White for editorial handling.Additional details
- Eprint ID
- 117884
- Resolver ID
- CaltechAUTHORS:20221116-601553800.2
- Agouron Institute
- Created
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2022-11-29Created from EPrint's datestamp field
- Updated
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2022-11-29Created from EPrint's last_modified field