Biogeochemical Connectivity Between Freshwater Ecosystems beneath the West Antarctic Ice Sheet and the Sub‐Ice Marine Environment
Year: 2020
Type: article
Abstract: Although subglacial aquatic environments are widespread beneath the Antarctic ice sheet, subglacial biogeochemistry is not well understood, and the contribution of subglacial water to coastal ocean carbon and nutrient cycling remains poorly constrained. The Whillans Subglacial Lake (SLW) ecosystem is upstream from West Antarctica's Gould‐Siple Coast ~800 m beneath the surface of the Whillans Ice Stream. SLW hosts an active microbial ecosystem and is part of an active hydrological system that drains into the marine cavity beneath the adjacent Ross Ice Shelf. Here we examine sources and sinks for organic matter in the lake and estimate the freshwater carbon and nutrient delivery from discharges into the coastal embayment. Fluorescence‐based characterization of dissolved organic matter revealed microbially driven differences between sediment pore waters and lake water, with an increasing contribution from relict humic‐like dissolved organic matter with sediment depth. Mass balance calculations indicated that the pool of dissolved organic carbon in the SLW water column could be produced in 4.8 to 11.9 yr, which is a time frame similar to that of the lakes’ fill‐drain cycle. Based on these estimates, subglacial lake water discharged at the Siple Coast could supply an average of 5,400% more than the heterotrophic carbon demand within Siple Coast embayments (6.5% for the entire Ross Ice Shelf cavity). Our results suggest that subglacial discharge represents a heretofore unappreciated source of microbially processed dissolved organic carbon and other nutrients to the Southern Ocean.
Source: Global Biogeochemical Cycles
DOI: 10.1029/2019gb006446
Institutions: Michigan Technological University, Montana State University, Bigelow Laboratory for Ocean Sciences, Institute for the Dynamics of Environmental Processes, National Research Council, Istituto di Scienze Polari, Ca' Foscari University of Venice, Louisiana State University, University of Florida, University of Washington, Aberystwyth University, Texas A&M University, University of Tennessee at Knoxville
Language: English
Topic: Polar Research and Ecology
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: bronze
Funders: National Science Foundation, American Association of University Women, Montana Space Grant Consortium, University of Nebraska-Lincoln, Michigan Technological University, Llywodraeth Cymru, Higher Education Funding Council for Wales, Montana Institute on Ecosystems, Office of Polar Programs, Division of Polar Programs
Awards: Collaborative Research: Integrative Study of Marine Ice Sheet Stability and Subglacial Life Habitats - Robotic Access to Grounding-zones for Exploration and Science (RAGES), G2251417751, 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), Collaborative Research: Integrative Study of Marine Ice Sheet Stability & Subglacial Life Habitats in W Antarctica - Lake & Ice Stream Subglacial Access Research Drilling (LISSARD), G4110228659, 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, G5778010920, IGERT: Geobiological Systems Science: Providing Connectivity across Molecular and Environmental Scales, 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, G7184168010, 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: W3007398331