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• 1. [Article] The Aeolian Flux of Calcium, Chloride and Nitrate to the McMurdo Dry Valleys Landscape: Evidence from Snow Pit Analysis

  We have determined the flux of calcium, chloride and nitrate to the McMurdo Dry Valleys region by analysing snow pits for their chemical composition and their snow accumulation using multiple records spanning ...

  Citation × Citation Citation Abstract Copy Title: The Aeolian Flux of Calcium, Chloride and Nitrate to the McMurdo Dry Valleys Landscape: Evidence from Snow Pit Analysis Author: Witherow, Rebecca A., Lyons, W. Berry, Bertler, Nancy A., Welch, Kathleen A., Mayewski, Paul A., Sneed, Sharon B., Nylen, Thomas H., Handley, Michael J., Fountain, Andrew G. Year: 2006 We have determined the flux of calcium, chloride and nitrate to the McMurdo Dry Valleys region by analysing snow pits for their chemical composition and their snow accumulation using multiple records spanning up to 48 years. The fluxes demonstrate patterns related to elevation and proximity to the ocean. In general, there is a strong relationship between the nitrate flux and snow accumulation, indicating that precipitation rates may have a great influence over the nitrogen concentrations in the soils of the valleys. Aeolian dust transport plays an important role in the deposition of some elements (e.g. Caý?) into the McMurdo Dry Valleys. soils. Because of the antiquity of some of the soil surfaces in the McMurdo Dry Valleys regions, the accumulated atmospheric flux of salts to the soils has important ecological consequences. Although precipitation may be an important mechanism of salt deposition to the McMurdo Dry Valley surfaces, it is poorly understood because of difficulties in measurement and high losses from sublimation. Title: The Aeolian Flux of Calcium, Chloride and Nitrate to the McMurdo Dry Valleys Landscape: Evidence from Snow Pit Analysis Author: Witherow, Rebecca A., Lyons, W. Berry, Bertler, Nancy A., Welch, Kathleen A., Mayewski, Paul A., Sneed, Sharon B., Nylen, Thomas H., Handley, Michael J., Fountain, Andrew G. Year: 2006 We have determined the flux of calcium, chloride and nitrate to the McMurdo Dry Valleys region by analysing snow pits for their chemical composition and their snow accumulation using multiple records spanning up to 48 years. The fluxes demonstrate patterns related to elevation and proximity to the ocean. In general, there is a strong relationship between the nitrate flux and snow accumulation, indicating that precipitation rates may have a great influence over the nitrogen concentrations in the soils of the valleys. Aeolian dust transport plays an important role in the deposition of some elements (e.g. Caý?) into the McMurdo Dry Valleys. soils. Because of the antiquity of some of the soil surfaces in the McMurdo Dry Valleys regions, the accumulated atmospheric flux of salts to the soils has important ecological consequences. Although precipitation may be an important mechanism of salt deposition to the McMurdo Dry Valley surfaces, it is poorly understood because of difficulties in measurement and high losses from sublimation. Close

• 2. [Article] Biogeochemical Evolution of Cryoconite Holes on Canada Glacier, Taylor Valley, Antarctica

  The cryoconite holes of the McMurdo Dry Valleys are simple, closed biogeochemical systems involving water, ice, mineral and organic debris, which serve as ecosystems for consortia of microorganisms. This ...

  Citation × Citation Citation Abstract Copy Title: Biogeochemical Evolution of Cryoconite Holes on Canada Glacier, Taylor Valley, Antarctica Author: Bagshaw, Elizabeth A., Tranter, Martyn, Fountain, Andrew G., Welch, Kathleen A., Basagic, Hassan J., Lyons, W. Berry Year: 2007 The cryoconite holes of the McMurdo Dry Valleys are simple, closed biogeochemical systems involving water, ice, mineral and organic debris, which serve as ecosystems for consortia of microorganisms. This study is the first to document the seasonal and annual chemical evolution of solutes in cryoconite holes. Samples of glacier ice, frozen cryoconite holes and those containing water were collected during the austral summer of 2005–2006. The isolation age was calculated from the excess Cl‾ in the holes, and varied from 0 to 5 years (a), consistent with the last hot summer when the cryoconite holes were open to the atmosphere. The holes progressively deepen with isolation age. Variations in DIC, DOC, K⁺ and SO²⁻₄ suggest that dissolution of primary minerals in the cryoconite debris, cyclical precipitation and dissolution of secondary carbonates, net photosynthesis over summer and net respiration during the autumnal freeze are the principal reactions which perturb the seasonal and annual solute concentrations in the holes. DOC is generated in the holes at a rate of 7.5 μg C cm⁻² a⁻¹, and non-sea-salt K⁺ accumulates in frozen holes at a rate of 0.073 μeq cm⁻² a⁻¹. We infer that C cycling is complex even in these otherwise simple systems. Title: Biogeochemical Evolution of Cryoconite Holes on Canada Glacier, Taylor Valley, Antarctica Author: Bagshaw, Elizabeth A., Tranter, Martyn, Fountain, Andrew G., Welch, Kathleen A., Basagic, Hassan J., Lyons, W. Berry Year: 2007 The cryoconite holes of the McMurdo Dry Valleys are simple, closed biogeochemical systems involving water, ice, mineral and organic debris, which serve as ecosystems for consortia of microorganisms. This study is the first to document the seasonal and annual chemical evolution of solutes in cryoconite holes. Samples of glacier ice, frozen cryoconite holes and those containing water were collected during the austral summer of 2005–2006. The isolation age was calculated from the excess Cl‾ in the holes, and varied from 0 to 5 years (a), consistent with the last hot summer when the cryoconite holes were open to the atmosphere. The holes progressively deepen with isolation age. Variations in DIC, DOC, K⁺ and SO²⁻₄ suggest that dissolution of primary minerals in the cryoconite debris, cyclical precipitation and dissolution of secondary carbonates, net photosynthesis over summer and net respiration during the autumnal freeze are the principal reactions which perturb the seasonal and annual solute concentrations in the holes. DOC is generated in the holes at a rate of 7.5 μg C cm⁻² a⁻¹, and non-sea-salt K⁺ accumulates in frozen holes at a rate of 0.073 μeq cm⁻² a⁻¹. We infer that C cycling is complex even in these otherwise simple systems. Close