Year: 2016
Type: dissertation
Abstract: The research presented in this dissertation focused on microbially-mediated biogeochemical processes and microbial ecology in Antarctic lakes and seawater. The major objective of my research was to examine the impact of environmentally imposed energetic constraints on nutrient cycling in mirobially-dominated systems. I used three ice-covered aquatic environments as natural laboratories for my investigations. The permanently ice-covered lakes of the McMurdo Dry Valleys (MCM) are located in Victoria Land, East Antarctica. The MCM have been studied intensively as part of the McMurdo Long Term Ecological Research Project since 1993. My work built on the extensive MCM dataset via high-throughput DNA sequencing to examine microbial communities from all three domains of life during the transition to winter, and by quantifying rates of dark inorganic carbon-fixation. This worked showed the importance of flexible metabolisms in the microbial ecosystems of the MCM lakes. The ocean beneath the McMurdo Ice Shelf (MIS) is the gateway between the Ross Sea and the dark ocean of the Ross Ice Shelf cavity. The area supports a biological carbon pump that is important in ocean biogeochemistry. Ice shelves around Antarctica are under threat of collapse, but little is known about the ecosystems beneath them. My work used a combination of biogeochemical measurements and assessment of microbial community structure to characterize the ecosystem beneath the MIS and its connections to the open ocean. The data showed the importance of nutrients advected from open water to the MIS cavity and projected an organic carbon deficit farther from the ice shelf edge. Subglacial Lake Whillans lies 800 m beneath the surface of the West Antarctic Ice Sheet near the end of a hydrological continuum that terminates in the ocean beneath the Ross Ice Shelf. Primarily through the use of biogeochemical rate measurements and determinations of organic matter quantity and quality, this work established the presence of an active microbial ecosystem in the subglacial lake, and estimated the annual subglacial flux of carbon and nutrients to the ocean under the ice shelf. Together, these projects show the importance of microbial activity in regional biogeochemical processes and of metabolic flexibility under energy-limited conditions.
Author: Trista J. Vick‐Majors
Language: English
Topic: Polar Research and Ecology
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
SDG: Climate action
Open Access status: green
Funders: National Science Foundation, American Association of University Women, Montana Space Grant Consortium, University of Cambridge, Montana Institute on Ecosystems, Comisión Nacional de Investigación Científica y Tecnológica, Office of Polar Programs, Division of Environmental Biology, Division of Polar Programs
Awards: Collaborative Research: Integrated High Resolution Chemical and Biological Measurements on the Deep WAIS Divide Core, Microbial Inventory Research Across Diverse Aquatic LTERs, Increased Connectivity in a Polar Desert Resulting from Climate Warming: McMurdo Dry Valley LTER Program, Graduate Research Fellowship Program (GRFP), Collaborative Research: Integrative Study of Marine Ice Sheet Stability and Subglacial Life Habitats - Robotic Access to Grounding-zones for Exploration and Science (RAGES), Collaborative Research: Integrative Study of Marine Ice Sheet Stability & Subglacial Life Habitats in W Antarctica - Lake & Ice Stream Subglacial Access Research Drilling (LISSARD), Collaborative Research: Greenland melt water Geomicrobiology, Collaborative Research: Integrative Study of Marine Ice Sheet Stability & Subglacial Life Habitats in W Antarctica - Lake & Ice Stream Subglacial Access Research Drilling (LISSARD), G3535456192, Collaborative Research: Integrative Study of Marine Ice Sheet Stability & Subglacial Life Habitats in W Antarctica - Lake & Ice Stream Subglacial Access Research Drilling (LISSARD), Collaborative Research: Integrative Study of Marine Ice Sheet Stability & Subglacial Life Habitats in W Antarctica - Lake & Ice Stream Subglacial Access Research Drilling (LISSARD), G5640791011, Collaborative Research: GeomicroBiology of Antarctic Subglacial Environments (GBASE) Beneath the Mercer and Whillans Ice Streams, Collaborative Research: GeomicroBiology of Antarctic Subglacial Environments (GBASE) Beneath the Mercer and Whillans Ice Streams, Collaborative Research: Integrative Study of Marine Ice Sheet Stability and Subglacial Life Habitats - Robotic Access to Grounding-zones for Exploration and Science (RAGES), Micro-Submersible Lake Exploration Device (MSLED) - Development of first generation propelled slim-hole device for subglacial lake (& aquatic enviornments ) exploration, EAGER: COLLABORATIVE RESEARCH: Habitability of Antarctic Lakes and Detectability of Microbial Life in Icy Environments by Aautonomous Year-round Instrumentation, Collaborative Research: Integrative Study of Marine Ice Sheet Stability and Subglacial Life Habitats - Robotic Access to Grounding-zones for Exploration and Science (RAGES), Collaborative Research: Integrative Study of Marine Ice Sheet Stability & Subglacial Life Habitats in W Antarctica - Lake & Ice Stream Subglacial Access Research Drilling (LISSARD), Collaborative Research: GeomicroBiology of Antarctic Subglacial Environments (GBASE) Beneath the Mercer and Whillans Ice Streams, Collaborative Research: Integrative Study of Marine Ice Sheet Stability and Subglacial Life Habitats - Robotic Access to Grounding-zones for Exploration and Science (RAGES)
OpenAlex ID: W2606414730