Dissolved and particulate trace metals in hydrothermal plumes at the Mid‐Atlantic Ridge

Seawater samples from the non‐buoyant plume have been collected at the TAG (26°N) and Snakepit (23°N) hydrothermal sites on the Mid‐Atlantic Ridge (MAR), and analysed for dissolved (<0.4 µm) and particulate (>0.4 µm) trace metals. Up to 50% of vent fluid Fe is present in the <0.4 µm fraction in the non‐buoyant plume. Increases in particulate concentrations of Cd are accompanied by a reduction in dissolved Cd to levels below ambient seawater. We show that dissolved Cd is scavenged from seawater in the buoyant section of the plume while Cd re‐dissolves from the particles in the non‐buoyant plume. Up to 43% of hydrothermally injected Cu is found in the <0.4 µm fraction in the non‐buoyant plume.