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dc.contributor.authorBehnke, Megan
dc.contributor.authorTank, Suzanne
dc.contributor.authorMcClelland, James W.
dc.contributor.authorHolmes, Robert M.
dc.contributor.authorHaghipour, Negar
dc.contributor.authorEglinton, Timothy
dc.contributor.authorRaymond, Peter A.
dc.contributor.authorSuslova, Anya
dc.contributor.authorZhulidov, Alexander V.
dc.contributor.authorGurtovaya, Tatiana
dc.contributor.authorZimov, Nikita
dc.contributor.authorZimov, Sergey
dc.contributor.authorMutter, Edda A.
dc.contributor.authorAmos, Edwin
dc.contributor.authorSpencer, Robert G. M.
dc.identifier.citationBehnke, M. I., Tank, S. E., McClelland, J. W., Holmes, R. M., Haghipour, N., Eglinton, T. I., Raymond, P. A., Suslova, A., Zhulidov, A. V., Gurtovaya, T., Zimov, N., Zimov, S., Mutter, E. A., Amos, E. & Spencer, R. G. (2023). Aquatic biomass is a major source to particulate organic matter export in large Arctic rivers. Proceedings of the National Academy of Sciences, 120(12), e2209883120.
dc.description.abstractArctic rivers provide an integrated signature of the changing landscape and transmit signals of change to the ocean. Here, we use a decade of particulate organic matter (POM) compositional data to deconvolute multiple allochthonous and autochthonous pan-Arctic and watershed-specific sources. Constraints from carbon-to-nitrogen ratios (C:N), δ13C, and Δ14C signatures reveal a large, hitherto overlooked contribution from aquatic biomass. Separation in Δ14C age is enhanced by splitting soil sources into shallow and deep pools (mean ± SD: −228 ± 211 vs. −492 ± 173‰) rather than traditional active layer and permafrost pools (−300 ± 236 vs. −441 ± 215‰) that do not represent permafrost-free Arctic regions. We estimate that 39 to 60% (5 to 95% credible interval) of the annual pan-Arctic POM flux (averaging 4,391 Gg/y particulate organic carbon from 2012 to 2019) comes from aquatic biomass. The remainder is sourced from yedoma, deep soils, shallow soils, petrogenic inputs, and fresh terrestrial production. Climate change-induced warming and increasing CO2 concentrations may enhance both soil destabilization and Arctic river aquatic biomass production, increasing fluxes of POM to the ocean. Younger, autochthonous, and older soil-derived POM likely have different destinies (preferential microbial uptake and processing vs. significant sediment burial, respectively). A small (~7%) increase in aquatic biomass POM flux with warming would be equivalent to a ~30% increase in deep soil POM flux. There is a clear need to better quantify how the balance of endmember fluxes may shift with different ramifications for different endmembers and how this will impact the Arctic system.en_US
dc.description.sponsorshipNational Science Foundation. South Russian Centre for Preparation and Implementation of International Projects. Northeast Science Station. Yukon River Inter Tribal Watershed Council. Aurora Research Institute.en_US
dc.description.tableofcontentsSignificance -- Abstract -- 1. Results -- 2. Discussion -- 3. Methods -- Data, materials, and software availability -- Acknowledgments -- Supporting information -- References.en_US
dc.publisherNational Academy of Sciencesen_US
dc.subjectparticulate organic matteren_US
dc.subjectcarbon fluxen_US
dc.titleAquatic biomass is a major source to particulate organic matter export in large Arctic riversen_US
dc.identifier.journalProceedings of the National Academy of Sciencesen_US

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  • Behnke, Megan
    Postdoctoral Researcher, Alaska Coastal Rainforest Center

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