GEOTRACES at AGU 2025: Sessions and Science Exchange Event

**Session OS23A – Physical and Biogeochemical Processes on the Warm Antarctic Continental Shelves
Tuesday, 16 December 2025, 14:15 – 15:45 (local time), 215-216 (NOLA CC),
Poster session: Tuesday, 16 December 2025

The “warm” continental shelves of West Antarctica, which include the Amundsen and Bellingshausen seas and the West Antarctic Peninsula, are characterized by enhanced on-shelf transport of Circumpolar Deep Water that helps determine on-shelf hydrographic and biogeochemical properties. This warm water also interacts with ice shelves, influencing vertical mixing, overturning rates and ice shelf mass loss, and potentially triggering marine ice sheet instabilities. Warm shelf regions are undergoing rapid, climate-sensitive changes, which have important implications for ocean circulation, biological production and biogeochemical exchange over spatial scales that may extend downstream to the Ross Sea and offshore waters of the Antarctic Circumpolar Current. For this interdisciplinary session, we invite contributions that focus on both observational and modeling studies of ocean circulation, sea ice-ocean and ice shelf-ocean interactions, biogeochemical processes and biological production in Antarctic warm-shelf settings. We are especially interested in studies that explore links among these thematic topics.

Conveners:

Madeline Mamer (Georgia Institute of Technology, Student Convener)
Kiya Riverman (University of Portland)
Peter Sedwick (Old Dominion University)
Robert Sherrell (Rutgers University)
Andrew Thompson (Caltech)

Full session details are here: https://agu.confex.com/agu/agu25/meetingapp.cgi/Session/272389

**Session A33A – Advances in Understanding Natural Aerosols and Gases in the Earth System
Wednesday, 17 December 2025, 14:15 – 15:45 (local time), 271 (NOLA CC)

Natural aerosols and gases play a key role in the Earth System. They link terrestrial, atmospheric, and ocean processes and understanding changes in their emission and deposition is essential for assessing the climate response to human activities. This session aims to evaluate the current state of knowledge on aerosols and gases from natural sources, such as wildfires, dust, volcanoes, sea spray, and biogenic emissions, and to identify their impacts on climate, biogeochemistry, and society across diverse spatial and temporal scales. Topics of interest include, but are not limited to: environmental drivers of natural aerosol and gas emissions; source apportionment; evolution of natural aerosol contribution to atmospheric composition; direct and indirect radiative effects; processes governing aerosol deposition and gas transfer at the air-sea and land-air interfaces; past and future changes to aerosol and gas fluxes; nutrient and contaminant exchange and impacts on ecosystems; and innovative observational approaches and modeling frameworks.

Convenors:
Yan Feng
Douglas Hamilton
Kostas Tsigaridis
Nicholas Meskhidze

Full session details are here: https://agu.confex.com/agu/agu25/meetingapp.cgi/Session/270649