5-8 Geochemical Responses Along a Hydrological Continuum in the McMurdo Dry Valleys, Antarctica

Session: Advances in Mountain Hydrology: Connecting Cryosphere, Surface, and Subsurface Processes

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Abstract:

In high latitude polar deserts, organisms rely on seasonal inputs of nutrients from wet and dry deposition of aerosols or weathering of wind-blown sediments. These materials are readily redistributed in the landscape through the movement of liquid water. In the McMurdo Dry Valleys (MDV), located in the Transantarctic Mountains (TAM) of Antarctica, there is a hydrological continuum that connects snow and glaciers with ephemeral streams, lakes, and the ocean in the austral summer. Aeolian sediments that are deposited on snow and ice can undergo chemical and physical weathering that generate solutes to support supraglacial and proglacial ecological communities. These sediments are carried along the continuum, settling during transport or deposited into closed-basin lakes or the ocean. Sediments can also be added to streams in the periglacial environment either by direct deposition or by streambank subsidence for areas of instability. As the climate in Antarctica continues to warm, the hydrological continuum in the Transantarctic Mountains will likely expand spatially and temporally, and landscape units will become geomorphically unstable.

This talk will explore sediment geochemical interactions with ice and glacier meltwater along the hydrological continuum in the MDV, starting with mineral weathering at the most upstream source atop alpine glaciers. During especially warm weather, glacier ablation zones will expand and produce more meltwater to hydrate and weather entrained sediments. In the periglacial environment, warming has destabilized permafrost-rich stream banks along incised stream channels, a process which is believed to drive major river alkalinity increases in the Arctic. We correlated permafrost subsidence in the MDV with stream geochemistry, utilizing long-term data collected by the MDV Long-Term Ecological Research project. Our work underscores the importance of understanding geochemical responses along hydrological continuums in vulnerable polar landscapes.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-11274

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