What is your role in Extreme 2003?

I am a Maxwell P. and Mildred H. Harrington Professor of Marine Studies at the University of Delaware and the leader of the chemistry component of the project.

What questions are you trying to answer and why?

Our group has two major goals during Extreme 2003. The first is to use our electrochemical analyzer and sensors from the DSV Alvin to measure oxygen, sulfur, and iron chemical constitutents [such as molecular oxygen, hydrogen sulfide, and iron monosulfide] in real time in diffuse-flow areas where biological organisms reside at hydrothermal vents. The simultaneous measurement of hydrogen sulfide and iron monosulfide indicates that pyrite (fool’s gold) and hydrogen gas are being formed. The hydrogen gas is a useful chemical that life forms such as Archaea, which are descendants of ancient life, can use for growth. We then will use this information to prospect for, or discover, life forms that can live off the reaction with hydrogen sulfide and iron monosulfide. This recently has been proposed to be an important process. Also, the simultaneous measurement of hydrogen sulfide and oxygen indicates that microbes can perform chemosynthesis (at vents some organisms use oxygen, hydrogen sulfide, and carbon dioxide to form organic matter without light).

Our second major goal is to successfully deploy a new electrochemical analyzer, which can be left unattended at a vent location. Our sensors will then be able to collect data continuously and to document any short-term changes up to about a week. These results will indicate how the chemistry of a diffuse flow site varies with time and should give us insight into how organisms respond to such chemical changes. Our work is important for (1) the development of new chemical sensors and (2) their application to understanding how chemistry and biology interact. We have documented that different organisms reside in different vent locations because of the chemical speciation of an element and how that speciation can affect organism growth. For example Riftia exist where hydrogen sulfide exists but not where iron monosulfide exists. Alvinella can exist where iron monosulfide is found because the iron detoxifies the sulfide when bound to sulfide.

Our work is funded by the National Science Foundation (NSF) and our group consists of talented analytical chemists (Charoenkwan Kraiya and Donald Nuzzio), ecologists (Brian Glazer and Tim Shank), and a geochemist (Greg Druschel). All these scientists are trained in the use of in situ electrochemcial sensors and have other expertise to bring to our effort.

What is your educational background?

I have a bachelor’s degree in chemistry and a doctorate in physical-inorganic chemistry. I began research in marine chemistry because I was confronted with some interesting questions by biology and geology colleagues who needed to know more about the different compounds that sulfur and iron can form in the environment.