My main research interests are water-rock interactions and the controls these, and other processes, exert on the chemistry of natural waters. A focus of my research is the chemistry of "black smoker" hot springs on the sea floor and their fluxes to the ocean. Most of our work is done with the Deep Submergence Vehicle (DSV) Alvin, although we have also used the Remotely Operated Vehicles (ROVs) Jason and Tiburon.

Studies of seafloor hydrothermal systems in my lab fall into two main categories: time series studies via repeat visits to several sites to understand the temporal evolution of these systems, and visits to a variety of sites with different fundamental properties such as depth, spreading rate, and rock substrates to constrain the global variability in vent fluid compositions. Our overriding goal is to understand the hydrothermal flux to the ocean. As part of this larger goal, we are working to understand the controls on hydrothermal fluid compositions; to use the fluid compositions as sensitive indicators of processes occurring within the upper oceanic crust; and to better understand the links between hydrothermal fluid compositions and the surrounding biological communities.

Since 1991 we have been working on the chemistry of the hot springs on the East Pacific Rise at 9-10 degrees north latitude. In 1991 we discovered a new volcanic eruption at this site and were able, for the first time, to observe "time zero" in terms of the hydrothermal system. We have samples collected from this site on about a dozen expeditions beginning in 1991, tracing the evolution of the hydrothermal system. These include research cruises in early 2002, late 2003, March 2004. Oceanic hydrothermal systems appear to be quite different in chemistry immediately following an eruption compared to what has previously been observed for their "steady-state" time period. Some of our cruises in this area have been in conjunction with biologists who are watching this area be re-colonized, and studying the evolution of this new biological community. As the energy source for these organisms comes primarily from hydrogen sulfide dissolved in the fluids, we have been monitoring the chemistry of the low temperature "diffuse" fluids to determine if changes in composition may be playing a role in the changes observed in the biological communities. This site is designated as an integrated study site (ISS) of the Ridge 2000 Program and our submitted manuscripts related to this site are available. Based on our results through 2002, we hypothesized that this site would soon have another volcanic eruption. We were funded to continue studying the evolution of the hydrothermal systems here over the next five years (2004-2009).

In spring 2006 evidence for a volcanic eruption was found, and NSF funded us for a special 'response cruise' to characterize the post-eruptive system in June-July 2006. We had the second cruise of our five year grant in November-December 2006. We are studying how this site has responded to this second eruption, and if the post-eruptive evolution is similar to that observed after the 1991 eruption. It appears that it is. In March 2004 we had deployed recording temperature probes in the black smokers at this site, and several of them survived the eruption. We therefore have a unique study site, the only place with two documented eruptions on the mid-ocean ridge, and the first time we have records of what the hot spring temperatures did during a volcanic eruption.

In spring 2007 we were part of a research expedition at one of the overlapping spreading centers (a major ridge offset) at 9 03'N, south of the eruption area we have studied so extensively from 9 16 - 9 51'N. We are working on comparing the hydrothermal system here to that further north. The magma supply system is unusually well documented at this overlapper, and is different from what is found along other parts of the ridge. A follow-up expedition in December 2007 returned to 9 North.

The 9-10 N area is not the only site of interest to us on the East Pacific Rise. In 2002 we also returned to 21 north latitude on the East Pacific Rise, where black smokers were first discovered, to see how these systems had evolved 23 years after their discovery. In late 1998 we used Alvin to work on the East Pacific Rise between 17 and 22 degrees south latitude. We sampled 40 hydrothermal vents, many of which had never been previously sampled. There were many questions about the hydrothermal systems on this part of the ridge, which is among the fastest spreading on the global ridge-crest system.

In 2000 and 2002, we also visited both the Escanaba and SeaCliff hydrothermal fields which occur on the Gorda Ridge (off California and Oregon) and are the only two known seafloor hydrothermal sites within US territorial waters.

We also work in the Atlantic Ocean, and have done time series work at the Lucky Strike hydrothermal field (1993, 1996, 1997). In addition to the TAG and Logatchev sites, which are also on the slow spreading Mid-Atlantic Ridge, the Lucky Strike site is helping us to understand how different substrate types affect vent fluids. Most of the Atlantic sites have been active for a very long time, and the rock beneath them appears to be highly altered.

In 2000 our expedition to the Central Indian Ridge, discovered a new hydrothermal field in the Indian Ocean (Edmond), and we also visited and sampled the Kairei hydrothermal field.

Each hydrothermal system is unique, and taken together they help us to understand fundamental processes that occur along the global mid-ocean ridge system. The water samples from these various sites are stored in my labs at UNH, and when we want to answer various questions, we turn to our library of water samples to address them.

Although water-rock reactions occur more quickly at "black smoker" temperatures and are visually most spectacular, they also play a major role in controlling the composition of surface and ground waters. My research interests also include the geochemical controls on these other types of natural waters.

Dr. Von Damm was chair of the US RIDGE Steering Committee (1995-1998), and is a Fellow of the American Geophysical Union.