Global change is strongly impacting Arctic freshwaters, integrated in a landscape that is quickly warming, undergoing significant changes in hydrological processes and permafrost thaw. All these changes are impacting soil organic matter cycling as well as hydrologic export from soils to adjacent streams and lakes as particulate and dissolved organic matter (DOM). As export and sources change, DOM is also expected to change, both in its chemical diversity and reactivity. DOM chemical diversity defines its availability for the microbial community and thus, ultimately the C export to the Arctic Ocean. Here, we evaluate how changes in landscape controls such as in hydrological connectivity and rock-weathering may impact DOM composition, stability and degradation. Our results include the evaluation of indices describing DOM chemical diversity as predictors of DOM degradation, the link between the distribution of such diversity across water bodies (including both streams and lakes/ponds) and its relation with landscape setting. These results provide valuable information and foster discussions on different approaches to enhance mechanistic understanding and assess biogeochemical responses of Arctic water bodies to climate change on a landscape scale.

Tutorial/Invited: Invited

Primary Presenter: Núria Catalán, IDAEA-CSIC (ncatalangarcia@gmail.com)

Authors:

Anne Kellerman, High Magnetic Field Laboratory Geochemistry Group and Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, Florida  (akellerman@fsu.edu)

Bertrand Guenet, Laboratoire des Sciences du Climat et de l'Environnement (LSCE), CNRS-UMR 8212, L'Orme des Merisiers-bat.714, 91190 Gif-sur-Yvette, France.   (guenet@biotite.ens.fr)

Tenna Riis, Department of Biology, Aarhus University, Aarhus, Denmark  (tenna.riis@bio.au.dk)

Dolly Kothawala, Uppsala University  (dolly.kothawala@ebc.uu.se)

Cecilie Marie Holmboe, Department of Biology, Aarhus University, Aarhus, Denmark  (cecilie.holmboe@bio.au.dk)

Marloes Groeneveld, Uppsala University  (marloes.groeneveld@ebc.uu.se)

Pau Giménez-Grau, Department of Biology, Aarhus University, Aarhus, Denmark  (pgimenezgrau@gmail.com)

Amy McKenna, High Magnetic Field Laboratory Geochemistry Group and Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, Florida  (mckenna@magnet.fsu.edu)

Jennifer Tank, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA  (jtank@nd.edu)

Kimberly Wickland, U.S. Geological Survey - Geosciences and Environmental Change Science Center , 3215 Marine Street, Boulder, CO 80303, USA  (kpwick@usgs.gov)

Robert Spencer, High Magnetic Field Laboratory Geochemistry Group and Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, Florida  (rgspencer@magnet.fsu.edu)

Ada Pastor, Department of Biology, Aarhus University, Aarhus, Denmark  (adapastor@gmail.com)