Biogeochemically diverse organic matter in Alpine glaciers and its downstream fate

Autor(en)

Gabriel Singer, Christina Fasching, Linda Wilhelm, Jutta Niggemann, Peter Steier, Thorsten Dittmar, Tom Battin

Abstrakt

Besides their role in the hydrological cycle(1), glaciers could play an important role in the carbon cycle(2-6). They store and transform organic carbon(5,6), which on release could support downstream microbial life(3). Yet the origin and composition of glacial organic carbon, and its implications for the carbon cycle, remain unclear. Here, we examine the molecular composition, radiocarbon age and bioavailability of dissolved organic matter (DOM) in 26 glaciers in the European Alps, using ultrahigh-resolution mass spectrometry, fluorescence spectroscopy and incubation experiments. We also measure carbon dioxide partial pressures in glacier-fed streams. We show that the glacier organic matter is highly diverse, and that a significant fraction of this material is bioavailable. Phenolic compounds derived from vascular plants or soil dominate, together with peptides and lipids, potentially derived from in situ microbial communities. Combustion products, in contrast, seem to contribute only marginally to the DOM sampled. We further show that organic matter bioavailability is positively correlated with in-stream carbon dioxide concentrations. We suggest that glacier-derived DOM contributes to downstream carbon cycling in glacier-fed streams. Our findings highlight the relevance of mountain glaciers for carbon cycling-a role that may change as glaciers recede.

Organisation(en)

Isotopenphysik

Externe Organisation(en)

Carl von Ossietzky Universität Oldenburg

Journal

Nature Geoscience

Band

5

Seiten

710-714

Anzahl der Seiten

5

ISSN

1752-0894

DOI

https://doi.org/10.1038/ngeo1581

Publikationsdatum

2012

Peer-reviewed

Ja

ÖFOS 2012

106026 Ökosystemforschung, 106020 Limnologie, 105105 Geochemie

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/eda532d3-f485-49ef-a6a2-a132f9cc4271