MIP: Interactions Between Archaea, Bacteria and their Viruses in the Anoxic Sediments of a Modern Evaporative Basin: Salton Sea, CA

University Of California-Santa Barbara, Santa Barbara CA

Investigators

Abstract

Many ecosystems on earth lack oxygen to breath and are devoid of multicellular life. The prime example of such an environment is the sediment covering ocean and lake bottoms throughout the world. Extending from the sea floor to several miles deep this environment covers nearly three quarters of Earth's surface. Despite the harsh conditions these environments harbor tremendous numbers of living organisms. Three major classes of organisms thrive here: Bacteria, Archaea and viruses. The interactions between these three forms of life are not well known and are the focus of this research project. Specifically the goal of this research is to determine how the abundance, distribution and activity of these three groups relate to changing environmental conditions. The primary hypothesis to be tested is that the Archaea, an lineage of single-celled organisms often associated with harsh environments, are adapted to out-compete Bacteria when conditions lead to starvation and energy stress. This research will be performed at the Salton Sea, CA and will employ state-of-the-art tools in molecular biology and geochemistry. In one pound of sediment from the Salton Sea there exist approximately 100 billion Bacteria and Archaea and approximately ten times as many viruses to infect them. This project is designed to differentiate the ecological roles and relatedness of Bacteria, Archaea and their viruses within the context of their environment. To date, broad principles governing the interactions of these groups is lacking, and little is known of which viruses infect which microbes. This research will determine the myriad of relationships between the diverse groups of single-celled organisms and their viruses, and may further distinguish the broad ecological roles of key groups. The timing for this research is critical as the rapidly expanding population of southern California is pressing for major water transfers away from desert agriculture to urban uses. The Salton Sea is a terminal basin and receives nearly all its water from agricultural runoff; proposed changes to the rate of water input will lead to dramatic changes in volume and salinity (and thus biogeochemistry and ecology) of the Salton Sea. While the exact fate of the Salton Sea is uncertain, major changes can be expected - there is a clear need to study the novel microbes of this environment. Direct impacts of this research include the training and education of undergraduate and graduate students as well as outreach to the general public. Graduate and undergraduate students will be incorporated into all aspects of the proposed field and laboratory research. Approximately twenty undergraduate students will be impacted each year by using the Salton Sea as a study site for an undergraduate field studies course. Socially-relevant findings from this work will be relayed to the public through presentations, participation in public forums, and the creation of a project website.