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dc.contributor.authorDrake, Travis W.  Concept link
dc.contributor.authorHemingway, Jordon D.  Concept link
dc.contributor.authorKurek, Martin  Concept link
dc.contributor.authorPeucker-Ehrenbrink, Bernhard  Concept link
dc.contributor.authorBrown, Kristina A.  Concept link
dc.contributor.authorHolmes, Robert M.  Concept link
dc.contributor.authorGaly, Valier  Concept link
dc.contributor.authorMoura, José M.  Concept link
dc.contributor.authorMitsuya, Miyuki  Concept link
dc.contributor.authorWassenaar, Leonard  Concept link
dc.contributor.authorSix, Johan  Concept link
dc.contributor.authorSpencer, Robert G. M.  Concept link
dc.date.accessioned2021-07-15T14:51:31Z
dc.date.issued2021-03-15
dc.identifier.citationDrake, T. W., Hemingway, J. D., Kurek, M. R., Peucker-Ehrenbrink, B., Brown, K. A., Holmes, R. M., Galy, V., Moura, J. M. S., Mitsuya, M., Wassenaar, L., I., Six, J., & Spencer, R. G. M. (2021). The pulse of the Amazon: fluxes of dissolved organic carbon, nutrients, and ions from the world's largest river. Global Biogeochemical Cycles, 35(4), e2020GB006895.en_US
dc.identifier.urihttps://hdl.handle.net/1912/27358
dc.descriptionAuthor Posting. © American Geophysical Union, 2021. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 35(4), (2021): e2020GB006895, https://doi.org/10.1029/2020GB006895.en_US
dc.description.abstractThe Amazon River drains a diverse tropical landscape greater than 6 million km2, culminating in the world's largest export of freshwater and dissolved constituents to the ocean. Here, we present dissolved organic carbon (DOC), organic and inorganic nitrogen (DON, DIN), orthophosphate (PO43−), and major and trace ion concentrations and fluxes from the Amazon River using 26 samples collected over three annual hydrographs. Concentrations and fluxes were predominantly controlled by the annual wet season flood pulse. Average DOC, DON, DIN, and PO43− fluxes (±1 s.d.) were 25.5 (±1.0), 1.14 (±0.05), 0.82 (±0.03), and 0.063 (±0.003) Tg yr−1, respectively. Chromophoric dissolved organic matter absorption (at 350 nm) was strongly correlated with DOC concentrations, resulting in a flux of 74.8 × 106 m−2 yr−1. DOC and DON concentrations positively correlated with discharge while nitrate + nitrite concentrations negatively correlated, suggesting mobilization and dilution responses, respectively. Ammonium, PO43−, and silica concentrations displayed chemostatic responses to discharge. Major and trace ion concentrations displayed clockwise hysteresis (except for chloride, sodium, and rubidium) and exhibited either dilution or chemostatic responses. The sources of weathered cations also displayed seasonality, with the highest proportion of carbonate- and silicate-derived cations occurring during peak and baseflow, respectively. Finally, our seasonally resolved weathering model resulted in an average CO2 consumption yield of (3.55 ± 0.11) × 105 mol CO2 km−2 yr−1. These results represent an updated and temporally refined quantification of dissolved fluxes that highlight the strong seasonality of export from the world's largest river and set a robust baseline against which to gauge future change.en_US
dc.description.sponsorshipThis work was supported by a grant from the Harbourton Foundation to R. G. M. Spencer and R. M. Holmes. T. W. Drake was supported by ETH Zurich core funding to J. Six. R. G. M. Spencer was additionally supported by NSF OCE-1333157.en_US
dc.publisherAmerican Geophysical Unionen_US
dc.relation.urihttps://doi.org/10.1029/2020GB006895
dc.subjectamazon riveren_US
dc.subjectdissolved organic carbonen_US
dc.subjectfluxesen_US
dc.subjectweatheringen_US
dc.subjectgeochemistryen_US
dc.titleThe pulse of the Amazon: fluxes of dissolved organic carbon, nutrients, and ions from the world's largest riveren_US
dc.typeArticleen_US
dc.description.embargo2021-09-15en_US
dc.identifier.doi10.1029/2020GB006895
dc.embargo.liftdate2021-09-15


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