Seasonal shift from biogenic to geogenic fluvial carbon caused by changing water sources in the wet-dry tropics

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dc.contributor.authorDuvert, Cen_AU
dc.contributor.authorHutley, LBen_AU
dc.contributor.authorBirkel, Cen_AU
dc.contributor.authorRudge, Men_AU
dc.contributor.authorMunksgaard, NCen_AU
dc.contributor.authorWynn, JGen_AU
dc.contributor.authorSetterfield, SAen_AU
dc.contributor.authorCendón, DIen_AU
dc.contributor.authorBird, MIen_AU
dc.date.accessioned2021-11-23T06:04:40Zen_AU
dc.date.available2021-11-23T06:04:40Zen_AU
dc.date.issued2020-02-05en_AU
dc.date.statistics2021-10-13en_AU
dc.description.abstractThe riverine export of carbon is expected to be driven by changes in connectivity between source areas and streams. Yet we lack a thorough understanding of the relative contributions of different water sources to the dissolved carbon flux, and of the way these contributions vary with seasonal changes in flow connectivity. Here we assess the temporal variations in water and associated dissolved inorganic carbon (DIC) sources and fluxes in a wet-dry tropical river of northern Australia over two years. We use linear mixing models integrated into a Bayesian framework to determine the relative contributions of rainfall, seasonal wetlands, shallow groundwater, and a deep carbonate aquifer to riverine DIC fluxes, which we relate to the age of water sources. Our results suggest extreme shifts in water and DIC sources between the wet and dry seasons. Under wet conditions, most DIC was of biogenic origin and transported by relatively young water sources originating from shallow groundwater and wetlands. As rainfall ceased, the wetlands either dried out or became disconnected from the stream network. From this stage, DIC switched to a geogenic origin, nearly entirely conveyed via older water sources from the carbonate formation. Our findings demonstrate the importance of changing patterns of connectivity when evaluating riverine DIC export from catchments. This work also illustrates the need to systematically partition DIC fluxes between biogenic and geogenic sources, if we are to quantify how the riverine export of carbon affects net carbon soil storage. © 2021 American Geophysical Unionen_AU
dc.description.sponsorshipThis work was supported by an ARC Discovery grant (DP160101497) and an ANSTO research grant (11066). C.B. was funded by a CDU Visiting Scholar grant.en_AU
dc.identifier.articlenumbere2019JG005384en_AU
dc.identifier.citationDuvert, C., Hutley, L. B., Birkel, C., Rudge, M., Munksgaard, N. C., Wynn, J. G., Setterfield, S. A., Cendón, D. I. & Bird, M. I. (2020). Seasonal shift from biogenic to geogenic fluvial carbon caused by changing water sources in the wet-dry tropics. Journal of Geophysical Research: Biogeosciences, 125(2), e2019JG005384. doi:10.1029/2019JG005384en_AU
dc.identifier.issn2169-8953en_AU
dc.identifier.issue2en_AU
dc.identifier.journaltitleJournal of Geophysical Research: Biogeosciencesen_AU
dc.identifier.urihttps://doi.org/10.1029/2019JG005384en_AU
dc.identifier.urihttps://apo.ansto.gov.au/dspace/handle/10238/12293en_AU
dc.identifier.volume125en_AU
dc.language.isoenen_AU
dc.publisherAmerican Geophysical Unionen_AU
dc.subjectSeasonsen_AU
dc.subjectWateren_AU
dc.subjectCarbonen_AU
dc.subjectAustraliaen_AU
dc.subjectBayesian statisticsen_AU
dc.subjectGround wateren_AU
dc.subjectAquifersen_AU
dc.titleSeasonal shift from biogenic to geogenic fluvial carbon caused by changing water sources in the wet-dry tropicsen_AU
dc.typeJournal Articleen_AU
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