OPENAIRE OpenAire VIRTA Bielefeld Academic Search Engine (BASE) DigitalCommons@USU UnpayWall HELDA - Digital Repository of the University of Helsinki Crossref Microsoft Academic Graph Europe PubMed Central Vrije Universiteit Amsterdam (VU Amsterdam) – Research Portal PubMed Central https://digitalcommons.usu.edu/context/biology_facpub/article/2820/viewcontent/2020GB006719.pdf https://doi.org/10.1029/2020gb006719 Global Biogeochemical Cycles Open Access 2020-11-18 Abstract<p>Permafrost degradation is delivering bioavailable dissolved organic matter (DOM) and inorganic nutrients to surface water networks. While these permafrost subsidies represent a small portion of total fluvial DOM and nutrient fluxes, they could influence food webs and net ecosystem carbon balance via priming or nutrient effects that destabilize background DOM. We investigated how addition of biolabile carbon (acetate) and inorganic nutrients (nitrogen and phosphorus) affected DOM decomposition with 28￢ﾀﾐday incubations. We incubated late￢ﾀﾐsummer stream water from 23 locations nested in seven northern or high￢ﾀﾐaltitude regions in Asia, Europe, and North America. DOM loss ranged from 3% to 52%, showing a variety of longitudinal patterns within stream networks. DOM optical properties varied widely, but DOM showed compositional similarity based on Fourier transform ion cyclotron resonance mass spectrometry (FT￢ﾀﾐICR MS) analysis. Addition of acetate and nutrients decreased bulk DOM mineralization (i.e., negative priming), with more negative effects on biodegradable DOM but neutral or positive effects on stable DOM. Unexpectedly, acetate and nutrients triggered breakdown of colored DOM (CDOM), with median decreases of 1.6% in the control and 22% in the amended treatment. Additionally, the uptake of added acetate was strongly limited by nutrient availability across sites. These findings suggest that biolabile DOM and nutrients released from degrading permafrost may decrease background DOM mineralization but alter stoichiometry and light conditions in receiving waterbodies. We conclude that priming and nutrient effects are coupled in northern aquatic ecosystems and that quantifying two￢ﾀﾐway interactions between DOM properties and environmental conditions could resolve conflicting observations about the drivers of DOM in permafrost zone waterways.</p> 0106 biological sciences 550 permafrost regions thermokarst vaikutukset ta1171 geosciences ikirouta carbon cycling 551 ravinteet 01 natural sciences nutrients cryosphere and high-latitude processes Biology Research Articles organic matter 0105 earth and related environmental sciences compositional similarities nutrients and nutrient cycling hiilen kierto ravinteiden kierrätys 15. Life on land rivers 6. Clean water nutrient effects 13. Climate action orgaaninen aines 1171 Geotieteet SDG 6 - Clean Water and Sanitation joet permafrost Benjamin W. Abbott, Sarah Shakil, Gilles Pinay, Michelle A. Baker, Ethan Wologo, Michaela M. Powell, Jorien E. Vonk, Sydney S. Foks, Stephanie A. Ewing, David C. Podgorski, Yuanhe Yang, Scott Zolkos, Scott Zolkos, Jay P. Zarnetske, Joshua F. Dean, Joshua F. Dean, Rebecca J. Frei, Rebecca J. Frei, Futing Liu, Jansen C. Howe, Robert G. M. Spencer, Sadie R. Textor, Robert M. Holmes, Pirkko Kortelainen, Jane K. Klassen, Joseph Lee-Cullin, Suzanne E. Tank, Kimberly P. Wickland, Samuel P. Bratsman, Jonathan A. O'Donnell, Jaana Kolehmainen, 2021-01-01 journalpaper Abstract<p>Permafrost degradation is delivering bioavailable dissolved organic matter (DOM) and inorganic nutrients to surface water networks. While these permafrost subsidies represent a small portion of total fluvial DOM and nutrient fluxes, they could influence food webs and net ecosystem carbon balance via priming or nutrient effects that destabilize background DOM. We investigated how addition of biolabile carbon (acetate) and inorganic nutrients (nitrogen and phosphorus) affected DOM decomposition with 28￢ﾀﾐday incubations. We incubated late￢ﾀﾐsummer stream water from 23 locations nested in seven northern or high￢ﾀﾐaltitude regions in Asia, Europe, and North America. DOM loss ranged from 3% to 52%, showing a variety of longitudinal patterns within stream networks. DOM optical properties varied widely, but DOM showed compositional similarity based on Fourier transform ion cyclotron resonance mass spectrometry (FT￢ﾀﾐICR MS) analysis. Addition of acetate and nutrients decreased bulk DOM mineralization (i.e., negative priming), with more negative effects on biodegradable DOM but neutral or positive effects on stable DOM. Unexpectedly, acetate and nutrients triggered breakdown of colored DOM (CDOM), with median decreases of 1.6% in the control and 22% in the amended treatment. Additionally, the uptake of added acetate was strongly limited by nutrient availability across sites. These findings suggest that biolabile DOM and nutrients released from degrading permafrost may decrease background DOM mineralization but alter stoichiometry and light conditions in receiving waterbodies. We conclude that priming and nutrient effects are coupled in northern aquatic ecosystems and that quantifying two￢ﾀﾐway interactions between DOM properties and environmental conditions could resolve conflicting observations about the drivers of DOM in permafrost zone waterways.</p> Stream Dissolved Organic Matter in Permafrost Regions Shows Surprising Compositional Similarities but Negative Priming and Nutrient Effects 10.1029/2020gb006719 676982