Trickle or Treat? Understanding the Role of Ice Sheets in Biogeochemical Cycles

Prof. Jon Hawkings

University of Pennsylvania

UiT The Arctic University of Norway

Monday April 15, 2024, 2 PM ET

Abstract:

Glaciers have covered ~10-30 % of land surface over the Quaternary and respond quickly to climatic change, yet are rarely considered in conceptual models of global biogeochemical cycles. For example, textbooks illustrating river catchment fluxes of solute and sediment to the ocean regularly display ice sheets (continental glaciers) as blank spots on maps, and our understanding of geochemical processes in a paleo context have rarely considered biogeochemical processes occurring on (supraglacial), under (subglacial) and in front (proglacial) of ice sheets. Research over the past two decades now indicates that far from being sterile, adynamic blocks of ice, glaciers are diverse biomes harboring truncated ecosystems on their surfaces (a “living skin”) and at their beds (the subglacial environment). Glaciers can also maintain very high physical denudation rates and chemical weathering rates similar to or above most global riverine catchments, with consequences for cycling of rock-derived nutrients and the carbon cycle. During this seminar I will present research that has tried to contextualize the role of ice sheets in elemental mobilization, cycling and export. My talk will focus on the potential sources, concentrations, speciation and transport of nutrient-type elements from glaciers into fjord and near-coastal ecosystems, using examples from the Greenland Ice Sheet. I will assert that (i) glaciers are far from the frozen wastelands they are often portrayed and should be considered as dynamic components of global biogeochemical cycles both now and in the past, but (ii) that there is nuance to how we understand glaciers at nutrient sources to the ocean.

Biosketch:

Jon Hawkings is an Assistant Professor in the Department of Earth and Environmental Science at the University of Pennsylvania. He is also an adjunct professor at UiT The Arctic University of Norway. He is biogeochemist with a broad interest in the cycling of elements through the Earth system and understanding how geochemical cycles can help regulate the Earth’s climate, but his research focus has been on the role of glaciers in biogeochemical cycles. He takes particular interest in the potential of glacial meltwater to influence the structure and productivity of ecosystems, biogeochemical weathering processes occurring at the bed of glaciers, and the mobilization of nutrients and toxic elements in freshwater environments and export to coastal ecosystems. His work is mostly observational, with projects in the last decade involving sample collection from Greenland, Antarctica, Patagonia, Svalbard and the Himalayas. He received his PhD from the School of Geographical Sciences at the University of Bristol and was a Marie Skłodowska-Curie Actions Fellow at GFZ-Potsdam/Florida State University before joining the faculty at University of Pennsylvania.

Webinar:

Event site: https://go.umd.edu/hawkings

Zoom Webinar: https://go.umd.edu/hawkingswebinar

Zoom Meeting ID: 950 3212 9563
Zoom password: essic

US Toll: +13017158592
Global call-in numbers: https://umd.zoom.us/u/aMElEpvNu

For IT assistance:
Cazzy Medley: cazzy@umd.edu

Resources:

Seminar schedule & archive: https://go.umd.edu/essicseminar

Seminar Google calendar: https://go.umd.edu/essicseminarcalendar

Seminar recordings on Youtube: https://www.youtube.com/user/ESSICUMD