Inputs of high-temperature fluids to the oceans along seafloor-spreadings centers, including the slow-spreading Mid- Atlantic Ridge (MAR), are now recognized as playing an important role in controlling the composition of seawater. Preliminary work on the Mid-Atlantic Ridge by Dr. Trefry's research group and several collaborators suggests that freshly precipitated iron oxides from high temperature vents serve as quantitatively important scavengers of vanadium, arsenic and other elements from seawater. If this is indeed occuring it would influence the global cycling of these elements. Dr. Trefry proposes to test several hypothese involving the scavenging role of vent-derived iron oxides on the chemistry of vanadium, arsenic, molybdenum and other oxyanions, as well as cadmium, copper and manganese in seawater. The study will focus on the TAG Hydrothermal Field on the MAR and involve collection and analysis of dissolved and particulate samples from a known vent plume. In addition to the scavenging study, his research will help address questions relating to the spatial density of vent sites on the MAR, changes in plume shape and chemistry over time, far-field transport of metal-rich particles, and the transport and cycling of carbon and sulfur with vent-related precipitates.
