Tracing the contribution of dust origins on deposition and phytoplankton carbon uptake in global oceans

Abstract. Dust provides iron, essential for marine phytoplankton growth, altering their carbon uptake capacity and affecting the global carbon cycle. However, due to the limited availability of observational parameters applied in evaluation models, there remains uncertainty in the contribution of marine dust deposition to carbon uptake. Here, we quantified the separate contributions of eleven major dust sources to dust deposition and marine ecological response to dust-borne iron in eight ocean regions based on a series of simulations constrained by multiple global observation datasets of iron solubility and total iron concentration in the oceans as well as iron content in the dust. Our simulations indicate that dust deposition could supply 11.1 Tg yr−1 of total iron and 0.4 Tg yr−1 of dissolved iron to the oceans. However, the study is limited by sparse observations and simplified assumptions, and further observations in undersampled regions would help to better constrain phytoplankton responses to dust-derived iron.