Research on hydrothermal systems is carried out primarily at deep-sea and on-land locations.  Often overlooked is the shallow-sea vent systems, which are similar in some ways but distinct in others from their deep-sea and on-land counterparts.  Shallow-sea hydrothermal systems are found on the tops of seamounts, on the flanks of volcanic islands, and in other near-shore environments characterized by high heat flow.  Their relatively easy accessibility makes them excellent natural laboratories to study a wide range of chemical, physical, and biological processes.  Past and present projects occur in collaboration with numerous scientists and institutions at vents sites in Italy (Aeolian Islands), Greece (Milos Island), Dominica, and Papua New Guinea (Ambitle Island).  Our projects include the characterization of new taxa, microbial community structures, metabolic reaction energetics, and the sulfur and arsenic biogeochemical cycles.