The PI's request funding to develop a Vent-Time Series Submersible Incubation Device (Vent-TSSID), a robotic micro-laboratory for routine application by the oceanographic community for measuring rates of relevant metabolic processes at hydrothermal vents at both in situ pressures and temperatures. Knowledge of the in situ metabolism of microorganisms carrying out CO2-fixation at deep-sea hydrothermal vents is very limited. Particularly lacking are studies measuring rates of autotrophic carbon fixation in situ, which is a measurement ultimately needed to constrain production in these ecosystems. Although recent data suggests that nitrate reduction either to N2 (denitrification) or to NH4 + (dissimilatory reduction of nitrate to ammonium, DNRA) might be responsible for a significant fraction of chemoautotrophic production, NO3 --reduction rates have never been measured in situ at hydrothermal vents.
The Vent-TSSID developed from this proposed work will be made available to the research community for use at other deep sea vents. This grant would fund 2 graduate students, one at WHOI and the other at Brown University. The PIs also have involved undergraduates in their research programs and plan to continue to do so. Dr. Sievert currently participates in the WHOI Science and Technology Education Partnership, and Dr. Rich has been an active participant in the Brown Environmental Fellows program.