A5012781709- Polar Research and Ecology
- Cryospheric studies and observations
- Microbial Community Ecology and Physiology
- Methane Hydrates and Related Phenomena
- Geology and Paleoclimatology Research
- Winter Sports Injuries and Performance
- Protist diversity and phylogeny
- Bacteriophages and microbial interactions
- Isotope Analysis in Ecology
- Marine Biology and Ecology Research
- Oil Spill Detection and Mitigation
- Wastewater Treatment and Nitrogen Removal
- Ocean Acidification Effects and Responses
- Cardiovascular and Diving-Related Complications
Texas A&M University
2020-2024
Louisiana State University
2011-2020
Louisiana State University Agricultural Center
2016
Subglacial Lake Whillans (SLW) is located beneath ∼800 m of ice on the Ice Stream in West Antarctica and was sampled January 2013, providing first opportunity to directly examine water sediments from an Antarctic subglacial lake. To minimize introduction surface contaminants SLW during its exploration, access borehole created using a microbiologically clean hot drill designed reduce number viability microorganisms drilling water. Analysis 16S rRNA genes (rDNA) amplified samples allowed...
Abstract The Whillans Ice Stream Subglacial Access Research Drilling (WISSARD) project will test the overarching hypothesis that an active hydrological system exists beneath a West Antarctic ice stream exerts major control on dynamics, and metabolic phylogenetic diversity of microbial community in subglacial water sediment. WISSARD explore Lake (SLW, unofficial name) its outflow toward grounding line where it is thought to enter Ross Shelf seawater cavity. Introducing contamination...
Diverse microbial assemblages inhabit subglacial aquatic environments. While few of these environments have been sampled, data reveal that organisms gain energy for growth from reduced minerals containing nitrogen, iron, and sulfur. Here we investigate the role microbially mediated sulfur transformations in sediments Subglacial Lake Whillans (SLW), Antarctica, by examining key genes involved dissimilatory oxidation reduction. The presence transformation throughout top 34 cm SLW changes with...
Subglacial microbial habitats are widespread in glaciated regions of our planet. Some these environments have been isolated from the atmosphere and sunlight for many thousands years. Consequently, ecosystem processes must rely on energy gained oxidation inorganic substrates or detrital organic matter. Lake Whillans (SLW) is one more than 400 subglacial lakes known to exist under Antarctic ice sheet; however, little about physiology energetics systems. When it was sampled through its 800 m...
Abstract Although subglacial aquatic environments are widespread beneath the Antarctic ice sheet, biogeochemistry is not well understood, and contribution of water to coastal ocean carbon nutrient cycling remains poorly constrained. The Whillans Subglacial Lake (SLW) ecosystem upstream from West Antarctica's Gould‐Siple Coast ~800 m surface Ice Stream. SLW hosts an active microbial part hydrological system that drains into marine cavity adjacent Ross Shelf. Here we examine sources sinks for...
Ice streams that flow into Ross Shelf are underlain by water-saturated sediments, a dynamic hydrological system, and subglacial lakes intermittently discharge water downstream across grounding zones of West Antarctic Sheet (WAIS). A 2.06 m composite sediment profile was recently recovered from Mercer Subglacial Lake, 15 deep cavity beneath 1087 thick portion the Stream. We examined microbial abundances, used 16S rRNA gene amplicon sequencing to assess community structures, characterized...
Ice shelves surround ∼ 75% of Antarctica's coastline and are highly sensitive to climate change; several have recently collapsed others predicted in the near future. Marine waters beneath ice harbor active ecosystems, while adjacent seas can be important areas bottom water formation. Despite their oceanographic significance, logistical constraints resulted few opportunities directly sample sub-ice shelf cavities. Here, we present first data on microbial diversity biogeochemistry McMurdo...
Abstract Subglacial Antarctic aquatic environments are important targets for scientific exploration due to the unique ecosystems they support and their sediments containing palaeoenvironmental records. Directly accessing these while preventing forward contamination demonstrating that it has not been introduced is logistically challenging. The Whillans Ice Stream Access Research Drilling (WISSARD) project designed, tested implemented a microbiologically chemically clean method of hot-water...
Microbes release exoenzymes into the environment to break down complex organic matter and nutrients simpler forms that can be assimilated utilized, thereby addressing their cellular carbon, nitrogen, phosphorus requirements. Despite its importance, factors associated with synthesis of are not clearly defined, especially for marine environment. Here, we found nitrogen acquisition were strongly correlated inorganic nutrient levels, while those carbon depended on type available. We also show a...
Cryopreservation of microorganisms in ancient glacial ice is possible if lethal levels macromolecular damage are not incurred and cellular integrity compromised via intracellular formation or recrystallization. Previously, a bacterium (isolate 3519-10) recovered from depth 3,519 m below the surface Vostok core was shown to secrete an ice-binding protein (IBP) that inhibits recrystallization ice. To explore advantage IBPs confer ice-entrapped cells, experiments were designed examine...
Following oil spills in aquatic environments, oil-associated flocculants observed within contaminated waters ultimately lead to the sedimentation of as marine snow (MOS). To better understand role aggregates hydrocarbon degradation and transport, we experimentally produced a MOS event using Gulf Mexico coastal amended with or plus dispersant. In addition formation MOS, smaller micrometer-scale (10- 150-μm) microbial were observed. Visual inspection these microaggregates revealed that they...