Crespo-Medina, M. ., Rutgers University, New Brunswick, NJ, USA, melitza@eden.rutgers.edu
Chatziefthimiou, A. ., Rutgers University, New Brunswick, NJ, USA, aspassaki@yahoo.gr
Bloom, N. ., Studio GeoChimica, Seattle, WA, USA, nicolasb@nickslab.org
Reinfelder, J. ., Rutgers University, New Brunswick, NJ, USA, reinfelder@envsci.rutgers.edu
Vetriani, C. ., Rutgers University, New Brunswick, NJ, USA, vetriani@imcs.rutgers.edu
Barkay, T. ., Rutgers University, New Brunswick, NJ, USA, barkay@aesop.rutgers.edu

INTERACTIONS OF CHEMOSYNTHETIC BACTERIA WITH MERCURY AT DEEP-SEA HYDROTHERMAL VENTS

Microorganisms that inhabit deep-sea hydrothermal vents have likely evolved in the presence of elevated concentrations of mercury, which is complexed with sulfur in these environments. Hence, chemosynthetic microbes, which obtain energy from the oxidation of sulfur compounds, are likely exposed to its toxicity. To test this hypothesis we collected fluids from diffuse flow vents at 9ºN on the East Pacific Rise (EPR). The concentration of total mercury (THg) in the samples ranged from 2.8 to 88.7 ng/L, while the abundance of mercury resistant thiosulfate oxidizing bacteria ranged from 0.2% to 24.6% of the total thiosulfate oxidizers. A correlation between mercury resistant bacteria and THg concentration suggested acclimation of these microbes to life in the presence of toxic mercury. Mercury speciation in the medium used to grow thiosulfate oxidizing bacteria showed the exclusive presence of negatively charged complexes of mercury thiosulfate, which were more bioavailable relative to mercuric nitrate complexes. Ongoing work on pure cultures of mercury resistant bacteria and their resistance mechanisms will lead to an understanding of the role of these organisms in mercury biogeochemistry in geothermal environments.

Poster presentation

Presentation is given by student: Yes
Session #:187
Date: 03-03-2008
Time: 17:30 - 19:30