Influence of ocean warming and acidification on trace metal biogeochemistry

Rising atmospheric CO₂ concentrations will have profound effects on atmospheric and hydrographic processes, which will ultimately modify the supple and chemistry of trace metals in the ocean. In addition to an increase in sea surface temperatures, higher CO₂ results in a decrease in seawater pH, known as ocean acidification, with implications for inorganic trace metal chemistry. Furthermore, direct or indirect effects of ocean acidification and ocean warming on marine biota will affect trace metal biogeochemistry via alteration of biological trace metal uptake rates and metal binding to organic ligands. We still lack a holistic understanding of the impacts of decreasing seawater pH and rising temperatures on different trace metals and marine biota, which complicates projections into the future. Here, we outline how ocean acidification and ocean warming will influence the inputs and cycling of Fe and other biologically relevant trace metals globally and regionally in high and low latitudes of the future ocean; we discuss uncertainties and highlight essential future research fields.