LEXEN: Microbial Life in Freshwater Hydrothermal Vent Systems

University Of Wisconsin-Milwaukee, Milwaukee WI

Investigators

Abstract

Abstract Microbial Life in Freshwater Hydrothermal Vent Systems. Carmen Aguilar EAR-085515 Understanding physical, chemical and biochemical characteristics of organisms that thrive at high temperatures has been a hot topic in exobiology and evolutionary biology. The organisms can be a link to ancient organisms and can be a key to the early evolution and development of life. One of the theories is that life arose under reducing conditions with high temperatures, similar to the hydrothermal vent systems that are currently found on Earth. These high temperature systems are relevant to understanding extreme environments on Earth as well as other planets and moons in our Solar System. Yellowstone Lake, WY is located in the caldera of the largest volcanic eruptions , the area is well known for its steaming geysers, shimmering thermal pools and bubbling mudpots. Equally relevant, though not visible, are the hydrothermal vents submerged under the northern area of Yellowstone Lake. These vents exist within spatial microbiogeochemical domains, which may mimic conditions of early Earth and perhaps other planets. The bacteria inhabiting vent systems have access to the reduced minerals and oxidizing agents necessary to support lithotrophic life. Mineral inputs to Yellowstone Lake come from a variety of sources, namely hydrothermal vents, ground water, rain water, flux from sediments and direct runoff (including tributaries). Approximately one third of Yellowstone Lake is directly influenced by hydrothermal activity (hot water vents and fumaroles). Mass balance suggests that microbes play an important part in modifying lake chemistry using vent chemical inputs. It is the intention of the proposed work to identify and characterize denizens of the extreme high temperature (to 143C) and caustic mineral (pH to 4.5, H2S to 1mM, elevated trace metals, etc.) output of freshwater hydrothermal vents and identify their metabolic signature upon the geochemical record. Using a Remote Operated Vehicle with well-developed sampling capabilities, we propose to sample water chemistry and microbial populations in underwater hot vents of the Yellowstone Geothermal Ecosystem. We will then conduct microbiological and geochemical analyses aimed at determining the metabolic processes promoting life in the habitats and tolerances of the organisms to extreme conditions. Particular effort will be directed towards elucidating mineral reactants and products of microbial metabolism under the harsh vent water conditions.