Collaborative research: what underpins the high bioavailability of glacier organic matter?

The National Science Foundation's Division of Environmental Biology (CFDA 47.074 - Biological Sciences) awarded $244,394 to the University of Alaska Southeast on August 1, 2025, for a three-year collaborative research project examining the bioavailability of dissolved organic matter (DOM) from glaciers. The research delivers scientific products through the development and application of advanced analytical methodologies, including a Respiratory Carbon Recovery System (RCRS), ultrahigh-resolution mass spectrometry, radiocarbon dating, and endmember source analysis. These analytical capabilities are deployed to investigate whether ancient carbon released from retreating glaciers achieves high bioavailability through modern microbial production on glacier surfaces, with investigations spanning multiple Alaskan glacier ecosystems across complete melt seasons. The project leverages partnerships with the National High Magnetic Field Laboratory to access world-leading analytical facilities and extends research capabilities in biogeochemistry, environmental biology, and Arctic science.

Beyond primary research deliverables, the project generates educational and outreach products including training for undergraduate students and an early-career researcher in biogeochemistry and environmental science. The research findings are disseminated to public audiences through science fairs and educational programming at the U.S. Forest Service Mendenhall Glacier Visitor Center in Juneau, Alaska. Results from this collaborative effort contribute to fundamental understanding of glacier-driven carbon cycling feedbacks in global biogeochemical systems, with direct implications for assessing the role of rapidly retreating glaciers in the Earth system.

Abstract

Glaciers are retreating at rapid rates, yet critical questions remain about their role in the earth system. As glaciers melt, they release ancient, biologically available dissolved organic matter (DOM) into water. This organic material can support downstream food webs, and release carbon that was trapped in ICE to the atmosphere. Recent research shows that glacier DOM is deposited from the atmosphere and also grown on the surface by algae and other microbial organisms. The relative importance of new versus ancient carbon sources driving the observed bioavailability of glacier DOM is largely unknown. This has important implications for understanding BIO-feedbacks from glaciers in global carbon cycling. This project provides opportunities for undergraduate students and an early-career researcher with training in biogeochemistry, environmental biology, and arctic science. The collaboration extends beyond the funded team to include scientists at the national high magnetic field laboratory, enabling knowledge transfer and access to world-leading analytical facilities. Results will be disseminated to the public through science fairs and educational outreach at the U.S. Forest service mendenhall glacier visitor center. The researchers have developed a respiratory carbon recovery system (rcrs) to directly analyze the age and source of glacier DOM consumed by microbes. Preliminary results support the hypothesis that modern microbial production on the glacier drives the high bioavailability of ancient DOM. Using analytical techniques, including ultrahigh-resolution mass spectrometry, radiocarbon dating, endmember source analysis, and rcrs incubation experiments, this research will investigate whether the source of respired glacier DOM varies between glacier ecosystems and through the melt season in the alaskan coastal mountains. This will establish if there is homogeneity in the glacial carbon released to downstream food webs that support ocean fisheries. These results will improve understanding of the quantity, timing and sources of carbon delivery to aquatic ecosystems in glacier runoff. Ultimately, these results will provide critical insights into how glacier ecosystems function and how their loss may affect downstream freshwater and marine ecosystems, and global carbon cycling, with ramifications for resource-dependent communities and fisheries. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the foundation's intellectual merit and broader impacts review criteria.- subawards are not planned for this award.