Evidence for Pathways of Concentrated Submarine Groundwater Discharge in East Antarctica from Helicopter-Borne Electrical Resistivity Measurements

Foley, Neil; Tulaczyk, S. M.; Grombacher, Denys; Doran, Peter T.; Mikucki, Jill A.; Myers, K. F.; Foged, Nikolaj; Dugan, Hilary A.; Auken, Esben; Virginia, Ross A.

doi:10.3390/hydrology6020054

Cited by 22 publications

(17 citation statements)

References 64 publications

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“…Most of the active lakes are coastal (Fricker et al, 2007;Fricker & Scambos, 2009), have fill-drain cycles of months to years (Siegfried & Fricker, 2018), and discharge water under the grounded ice sheet into the sub-ice shelf ocean. There is also evidence for water flow from groundwater stored in East Antarctica (Foley et al, 2019) and from lakes in the continental interior (Wright & Siegert, 2012), implying wide hydrological dispersal of subglacial materials across Antarctica to the coastal margin.…”

Section: Introductionmentioning

confidence: 99%

Biogeochemical Connectivity Between Freshwater Ecosystems beneath the West Antarctic Ice Sheet and the Sub‐Ice Marine Environment

Vick‐Majors

Michaud

Skidmore

et al. 2020

Global Biogeochemical Cycles

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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.

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Section: Introductionmentioning

confidence: 99%

Biogeochemical Connectivity Between Freshwater Ecosystems beneath the West Antarctic Ice Sheet and the Sub‐Ice Marine Environment

Vick‐Majors

Michaud

Skidmore

et al. 2020

Global Biogeochemical Cycles

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“…Shanhun et al 9 and Risk et al 54 suggested an abiotic origin of CO 2 based on the isotopic analyses, reporting very high positive φCO 2 values that cannot be explained by normal microbial activity. We suggest that the measured high anomaly values, originate from the subsurface brine system 31,49 , and are linked to permafrost cap discontinuities at the edges of the valley (fractures or buried local faults).…”

Section: Discussionmentioning

confidence: 87%

Antarctic Permafrost Degassing Revealed By Extensive Soil Gas and Co2 Flux Survey in Taylor Valley

Ruggiero

Sciarra

Mazzini

et al. 2021

Preprint

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McMurdo Dry Valleys comprise 10% of the ice-free soil surface areas in Antarctica. Permafrost stability plays an important role in C-cycle as it potentially stores considerable quantities of greenhouse gases. While the geomorphology of the Dry Valleys reflects a long history of changing climate conditions, comparison with the rapidly warming Northern polar region suggests that future climate and ecosystems may change more rapidly from permafrost degradation. In Austral summer 2019/2020 a comprehensive sampling of soil gases and CO2 flux measurements was undertaken in the Taylor Valley, with the aims to identify potential presence of soil gases in the active layer. The results obtained show high concentrations of CH4, CO2, He and an increasing CO2 flux rate. We identify the likely source of the gas to be from dissolved gases in deep brine moving from inland (potentially underneath the Antarctic Ice Sheet) to the coast at depth beneath the permafrost layer.

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“…The MDVs are located within the Transantarctic Mountains and make up the largest ice-free region in Antarctica (Levy, 2013). Mean annual valley bottom temperatures in TV range from −14.7 to −23.0 • C (Obryk et al, 2020), and the region receives between 3-50 mm water equivalent of precipitation per year (Fountain et al, 2010). Lakes in the MDVs have 3-5 m thick perennial ice covers and vary in volume, chemistry, and biological activity (Lyons et al, 2000).…”

Section: Site Description and Field Campaignmentioning

confidence: 99%

Thermal legacy of a large paleolake in Taylor Valley, East Antarctica, as evidenced by an airborne electromagnetic survey

et al. 2021

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Abstract. Previous studies of the lakes of the McMurdo Dry Valleys have attempted to constrain lake level history, and results suggest the lakes have undergone hundreds of meters of lake level change within the last 20 000 years. Past studies have utilized the interpretation of geologic deposits, lake chemistry, and ice sheet history to deduce lake level history; however a substantial amount of disagreement remains between the findings, indicating a need for further investigation using new techniques. This study utilizes a regional airborne resistivity survey to provide novel insight into the paleohydrology of the region. Mean resistivity maps revealed an extensive brine beneath the Lake Fryxell basin, which is interpreted as a legacy groundwater signal from higher lake levels in the past. Resistivity data suggest that active permafrost formation has been ongoing since the onset of lake drainage and that as recently as 1500–4000 years BP, lake levels were over 60 m higher than present. This coincides with a warmer-than-modern paleoclimate throughout the Holocene inferred by the nearby Taylor Dome ice core record. Our results indicate Mid to Late Holocene lake level high stands, which runs counter to previous research finding a colder and drier era with little hydrologic activity throughout the last 5000 years.

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Evidence for Pathways of Concentrated Submarine Groundwater Discharge in East Antarctica from Helicopter-Borne Electrical Resistivity Measurements

Abstract: The Southern Ocean receives limited liquid surface water input from the Antarctic continent.

Cited by 22 publications

References 64 publications

Biogeochemical Connectivity Between Freshwater Ecosystems beneath the West Antarctic Ice Sheet and the Sub‐Ice Marine Environment

Biogeochemical Connectivity Between Freshwater Ecosystems beneath the West Antarctic Ice Sheet and the Sub‐Ice Marine Environment

Antarctic Permafrost Degassing Revealed By Extensive Soil Gas and Co2 Flux Survey in Taylor Valley

Thermal legacy of a large paleolake in Taylor Valley, East Antarctica, as evidenced by an airborne electromagnetic survey

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