A microbiologically clean strategy for access to the Whillans Ice Stream subglacial environment

• Published in: Antarctic science Vol. 25; no. 5; pp. 637 - 647
• Main Authors: Priscu, John C., Achberger, Amanda M., Cahoon, Joel E., Christner, Brent C., Edwards, Robert L., Jones, Warren L., Michaud, Alexander B., Siegfried, Matthew R., Skidmore, Mark L., Spigel, Robert H., Switzer, Gregg W., Tulaczyk, Slawek, Vick-Majors, Trista J.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.10.2013
• Subjects: Biological Sciences; Boreholes; Drilling; Earth, ocean, space; Environmental stewardship; Exact sciences and technology; External geophysics; Freshwater; Geophysics. Techniques, methods, instrumentation and models; Ice shelves; Marine; Microbial contamination; Seawater; Snow. Ice. Glaciers; Water outflow; Water treatment; polar regions; West Antarctica; Antarctica; Ross Ice Shelf; PS, Antarctica, Ross Ice Shelf; environmental stewardship; subglacial aquatic environments; hot water drilling; clean access; Subglacial lake; Hot water processes; Microbiology; deep drilling; Disinfection; Exploration; Wasteless technology; subglacial environment; water treatment; Ice shelf; Polar region; Biological contamination
• ISSN: 0954-1020; 1365-2079
• DOI: 10.1017/S0954102013000035

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 that exerts a major control on ice dynamics, and the metabolic and phylogenetic diversity of the microbial community in subglacial water and sediment. WISSARD will explore Subglacial Lake Whillans (SLW, unofficial name) and its outflow toward the grounding line where it is thought to enter the Ross Ice Shelf seawater cavity. Introducing microbial contamination to the subglacial environment during drilling operations could compromise environmental stewardship and the science objectives of the project, consequently we developed a set of tools and procedures to directly address these issues. WISSARD hot water drilling efforts will include a custom water treatment system designed to remove micron and sub-micron sized particles (biotic and abiotic), irradiate the drilling water with germicidal ultraviolet (UV) radiation, and pasteurize the water to reduce the viability of persisting microbial contamination. Our clean access protocols also include methods to reduce microbial contamination on the surfaces of cables/hoses and down-borehole equipment using germicidal UV exposure and chemical disinfection. This paper presents experimental data showing that our protocols will meet expectations established by international agreement between participating Antarctic nations.