Why Study Life in the Cold?

Despite the fact that >80% of the biosphere (by volume) is permanently below 5°C and most of the biomass is microbial, very little is known about the biology of microorganisms inhabiting permanently cold environments.  Our research efforts are contributing to fill this knowledge gap through laboratory- and field-based projects aimed at understanding the nature and biogeochemical contributions of microbial life in environments beneath polar ice sheets and in the high atmosphere.

Current Research Projects:

Subglacial Antarctic Lakes Scientific Access (SALSA): Integrated Study of Carbon Cycling in Hydrologically-active Subglacial Environments

The Antarctic subglacial environment remains one of the least explored regions on Earth. This project will examine the physical and biological characteristics of Subglacial Lake Mercer, a lake that lies 1200m beneath the West Antarctic Ice Sheet. This study will address key questions relating to the stability of the ice sheet, the subglacial hydrological system, and the deep-cold subglacial biosphere. The education and outreach component aims to widely disseminate results to the scientific community and to the general public through short films, a blog, and a website. Subglacial Lake Mercer is one of the larger hydrologically active lakes in the southern basin of the Whillans Ice Plain, West Antarctica. It receives about 25 percent of its water from East Antarctica with the remainder originating from West Antarctica, is influenced by drain/fill cycles in a lake immediately upstream (Subglacial Lake Conway), and lies about 100 km upstream of the present grounding line of the Ross Ice Shelf. This site will yield information on the history of the Whillans and Mercer Ice Streams, and on grounding line migration. The integrated study will include direct sampling of basal ice, water, and sediment from the lake in concert with surface geophysical surveys over a three-year period to define the hydrological connectivity among lakes on the Whillans Ice Plain and their flow paths to the sea. The geophysical surveys will furnish information on subglacial hydrology, aid the site selection for hot-water drilling, and provide spatial context for interpreting findings. The hot-water-drilled boreholes will be used to collect basal ice samples, provide access for direct measurement of subglacial physical, chemical, and biological conditions in the water column and sediments, and to explore the subglacial water cavities using a remotely operated vehicle equipped with sensors, cameras, and sampling equipment. Data collected from this study will address the overarching hypothesis "Contemporary biodiversity and carbon cycling in hydrologically-active subglacial environments associated with the Mercer and Whillans ice streams are regulated by the mineralization and cycling of relict marine organic matter and through interactions among ice, rock, water, and sediments". The project will be undertaken by a collaborative team of scientists, with expertise in microbiology, biogeochemistry, hydrology, geophysics, glaciology, marine geology, paleoceanography, and science communication.
Funding: National Science Foundation, Antarctic Integrated System Science

ARCHIMEDES [A Really Cool High Impact Method for Exploring Down into Europan Subsurface]

Subsurface exploration of ocean worlds ultimately requires significant ice penetration. We propose further development of an entirely novel ice penetrating technology, using laser light carried by an optical fiber tether and emitted from the probe’s nose cone directly into the ice. This technology has critical benefits over conventional “hot point” melt probes and mechanical drills and is particularly advantageous for the extreme cold and vacuum environment on ocean worlds. Currently our direct laser probe is targeted for very efficient penetration of 1 to 10 meters depth and scales well for penetration of 10s to 100s of meters. Preliminary experiments conducted at Stone Aerospace over a range of power levels and ice penetration rates produced excellent results exceeding expectations (TRL 3) and achieving the fastest recorded cryobot descent speed to date. We propose to develop, build, and characterize a direct-laser-based penetrator system, refining and advancing this technology to TRL 5. We will test a range of probe diameters and laser power levels under relevant extra-terrestrial environmental conditions. Additionally, we will investigate fiber-coupled optical biomarker sensors that take advantage of the laser’s fiber optic tether.  
: National Aeronautics and Space Administration, COLDTech

Research on Airborne Ice Nucleating Species (RAINS)

The presence of microorganisms in the atmosphere has a multitude of consequences for human, animal, and plant health primarily due to their long range and recurrent transport. Furthermore, numerous studies have also provided evidence that atmospheric microbiota play an important role in cloud development, cloud chemistry, and precipitation generation. However, because of the challenges and complexity of measurements required to capture spatial and temporal variability in the Earth-atmosphere system, the abundance, diversity and flux of airborne microbiota remain largely unknown. Moreover, most aerobiological investigations to date have used only cultivation-based approaches to examine dispersal of specific animal or plant pathogens. Despite the atmosphere’s potentially fundamental role in microbial dispersal, its biodiversity remains relatively unexplored. Microorganisms are among the best-known biological ice nucleators, which may allow them to impact meteorology and promote their airborne dispersal during precipitation events. Collectively, this motivates the proposed effort to characterize the diversity of microbial species that are distributed to terrestrial environments during precipitation events. RAINS merges the three dimensions of biodiversity in its goals to (1) characterize the taxonomic diversity in the lower atmosphere and precipitation (including precipitation that occurred between 1794 AD and present and which is preserved in glacial ice), (2) determine the genetic diversity in regard to gene content of microbial communities and of individual IN active bacteria in the lower atmosphere and precipitation, and (3) examine the functional diversity in regard to the diversity of ice nucleation active species and the proteins/macromolecules that allow these species to nucleate ice. RAINS will be transformative in determining which microbial taxa are carried to the Earth’s surface via precipitation, which of these microbes are ice nucleators and may contribute to precipitation generation, and which of these taxa present possible inoculum sources for human, animal, or plant disease outbreaks.
Funding: National Science Foundation, Dimensions of Biodiversity 

A Transoceanic Aerobiology Biodiversity Study (TABS) to Characterize Microorganisms in Asian and African Dust Plumes Reaching North America

The objectives of the proposed Transoceanic Aerobiology Biodiversity Study (TABS) are the following: (1) Identify technologies for land-, water-, and air-based measurements of microbial communities in Asian and African dust plumes. (2) Explore methods to differentiate between baseline airborne biodiversity (i.e., non-dusty days) from the biodiversity unique to arriving dust plumes. (3) Study metagenomic protocols to optimize the recovery and identification of the widest possible range of viable airborne microbial species recovered from the hardware identified in #1 above. (4) Evaluate molecular microbiology approaches and hypobaric chamber experimental protocols to scope out how to simulate tropospheric and stratospheric environments in order to study the survival, metabolism, growth, and possible adaptation of microorganisms under atmospheric conditions present during transport. (5) Develop a remote sensing modeling approach to correlate microbial biodiversity to ground, airborne, and satellite measurements of atmospheric aerosols (e.g., ground LIDAR, satellites like MODIS, CALIOP, CATS), in which the aerosols are used as proxies for tracking transoceanic movement of airborne microorganisms. (6) Predict possible microbial and aerosol interactions among atmosphere-, ocean-, and land-based ecosystems. And (7), identify the technologies, logistics, resources, timelines, and budgets required to develop a 5-year field campaign that characterizes the biodiversity of Asian and African transoceanic dust plumes, and models their global transport.
Funding: National Aeronautics and Space Administration, Biodiversity

EMBER: Exploring Microbial Bioaerosol Effects on Rainfall 

Certain microorganisms are ice nucleation active – they are highly efficient freeze catalysts – and facilitate ice formation at temperatures warmer than other atmospheric aerosols. Since the freezing of water aerosols is essential for precipitation generation in temperate regions, this implies that some bioaerosols could affect meteorological processes in important ways. It is also likely that ice nucleating species benefit from this interaction and use precipitation as a vehicle for dispersal. Collectively this motivates the proposed EMBER (Exploring Microbial Bioaerosol Effects on Rainfall) project and efforts to examine how land use and cover at the Ordway Swisher Biological Station (OSBS; Melrose, FL) effect local atmospheric distributions of biological ice nucleating particles (INPs). A specific emphasis of EMBER is to test the hypothesis that biomass burning is a source of highly active biological INPs to the atmosphere. The prescribed burn program, number of managed land covers, and wealth of environmental data available at the OSBS provide an ideal platform for the proposed research.  
: Orway Swisher Biological Station Jumpstart Award Program (McIntire-Stennis, National Institute of Food and Agriculture - United States Department of Agriculture)

Research Sponsors:



Past Grants:

GeomicroBiology of Antarctic Subglacial Environments (GBASE) Beneath the Whillans Ice Stream

Funding: National Science Foundation, Antarctic Integrated System Science

VALKYRIE (Very-Deep Autonomous Laser-Powered Kilowatt-Class Yo-Yoing Robotic Ice Explorer)

Funding: National Aeronautics and Space Administration, Astrobiology Science and Technology for Exploring Planets (ASTEP)

DNA Repair Under Frozen Conditions: Implications for the Longevity of Microorganisms in Terrestrial and Extraterrestrial Ices

Funding: National Aeronautics and Space Administration, Astrobiology: Exobiology and Evolutionary Biology

Greenland melt water Geomicrobiology

Funding: National Science Foundation, Arctic Sciences Division

High Elevation Impact Sampling Tool (HEIST)

Funding: National Aeronautics and Space Administration, Undergraduate Student Instrument Project (USIP), Educational Flight Opportunity for University Undergraduate Students

Modes of Adaptation, Resistance, and Survival for Life Inhabiting a Freeze-dried-radiation-bathed Environment (MARSLIFE)

Funding: National Aeronautics and Space Administration (Experimental Program to Stimulate Competitive Research; EPSCoR) and the Louisiana Board of Regents

Biogeochemistry and Geomicrobiology of Taylor Glacier Basal Ice

Funding: National Science Foundation, Antarctic Organisms and Ecosystems

High Altitude BIological Testing of the ATmosphere (HABITAT): Developing a Sampling Platform to Measure the Upper Boundaries of the Biosphere

Funding: LaSPACE, 2009-10

Microbial Activity in Solid Ice: Implications for Modifying the CO2 Record in Ice Cores

Funding: National Science Foundation, Research in Biogeosciences, 2005-09

Biological Ice Nuclei: is There a Bioprecipitation Cycle?

Funding: Louisiana State University, Office of Research and Economic Development, 2007-08