Mercury deposition through the Permo-Triassic Biotic Crisis

- The Permo-Triassic Biotic Crisis has significant fluctuations in mercury.
- Hg strongly correlates with total organic carbon.
- A natural buffering system limits impact of transient Hg deposition events.
- Extreme volcanic events can overload marine systems.

A 6.7 million year record of marine sedimentation through the Permo Triassic Biotic Crisis shows notable shifts in mercury concentrations that varied over an order of magnitude (0.002 to 0.116 μg/g). Mercury concentrations correlate strongly with total organic carbon, showing both parallel increasing and decreasing trends over geologic time scales. Results suggest that changes in bioproductivity strongly influence mercury sequestration into marine sediment. This may provide insight to potential marine response to modern anthropogenic Hg loading, and supports models that suggest enhanced bioproductivity that due to recent climate has increased Hg sequestration over time.