The Influence of Warming on Phosphorus Burial in Continental Margin Sediments

The marine phosphorus cycle plays a critical role in regulating rates of primary productivity and thus the size of the marine biosphere. Yet, the cumulative effects of temperature change—and warming, in particular—on marine phosphorus burial remain poorly understood. Here, we explore a benthic biogeochemical model that accounts for the compounded effect of temperature on the kinetics of key diagenetic reaction pathways, diffusion coefficients, seawater pH, dissolved O2 concentration and bioturbation, in order to provide a new predictive framework for understanding the temperature response associated with P burial in continental margin settings. We find that temperature has a direct and positive impact on marine phosphorus burial, as it directly increases the formation rate of key mineral P-removal pathways—foremost carbonate fluorapatite (CFA). The increase in authigenic P burial during climate warming is likely to partially counter the effects of increased water-column P regeneration rate during climate warming events, and thus influence the extent of oceanic anoxia and organic matter burial, a factor that should be considered when assessing the response of the P cycle in the face of warming.