HomePublications

Environmental Controls on the Riverine Export of Dissolved Black Carbon

Research output: Contribution to journalArticle

Open Access permissions

Open

Documents

DOI

Authors

  • Matthew Jones
  • Luiz E. O. C. Aragão
  • Thorsten Dittmar
  • Carlos E. de Rezende
  • Marcelo G. Almeida
  • Ben T. Johnson
  • Jomar Marques
  • Jutta Niggemann
  • Thiago Rangel
  • Timothy Quine

Organisational units

Abstract

Each year, tropical rivers export a dissolved organic carbon (DOC) flux to the global oceans that is equivalent to ~4% of the global land sink for atmospheric CO2. Among the most refractory fractions of terrigenous DOC is dissolved black carbon (DBC), which constitutes ~10% of the total flux and derives from the charcoal and soot (aerosol) produced during biomass burning and fossil fuel combustion. Black carbon (BC) has disproportionate storage potential in oceanic pools and thus its export has implications for the fate and residence time of terrigenous organic carbon (OC). In contrast to bulk DOC, there is limited knowledge of the environmental factors that control riverine fluxes of DBC. We thus completed a comprehensive assessment of the factors controlling DBC export in tropical rivers with catchments distributed across environmental gradients of hydrology, topography, climate and soil properties. Generalised linear models explained 70% and 64% of the observed variance in DOC and DBC concentrations, respectively. DOC and DBC concentrations displayed coupled responses to the dominant factors controlling their riverine export (soil moisture; catchment slope, and; catchment stocks of OC or BC, respectively) but varied divergently across gradients of temperature and soil properties. DBC concentrations also varied strongly with aerosol BC deposition rate, indicating further potential for deviation of DBC fluxes from those of DOC due to secondary inputs of DBC from this unmatched source. Overall, this study identifies the specific drivers of BC dynamics in river catchments and fundamentally enhances our understanding of refractory DOC export to the global oceans.

Details

Original languageEnglish
Pages (from-to)849-874
JournalGlobal Biogeochemical Cycles
Volume33
Issue number7
Early online date20 May 2019
DOIs
Publication statusPublished - Jul 2019
Peer-reviewedYes

Downloads statistics

No data available

View graph of relations

ID: 158621827

Related by author
  1. Fossil CO2 emissions in the post-COVID-19 era

    Research output: Contribution to journalArticle

  2. Global emissions are down by an unprecedented 7% — but don’t start celebrating just yet

    Research output: Contribution to specialist publicationArticle

  3. Global Carbon Budget 2020

    Research output: Contribution to journalArticle

  4. Climate Change Increases the Risk of Wildfires: September 2020

    Research output: Contribution to specialist publicationArticle