Human impact on long-term organic carbon export to rivers

Valentina Noacco*, Thorsten Wagener, Fred Worrall, Tim P Burt, Nicholas J.K. Howden

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

36 Citations (Scopus)
556 Downloads (Pure)


Anthropogenic landscape alterations have increased global carbon transported by rivers to oceans since preindustrial times. Few suitable observational data sets exist to distinguish different drivers of carbon increase, given that alterations only reveal their impact on fluvial dissolved organic carbon (DOC) over long time periods. We use the world's longest record of DOC concentrations (130 years) to identify key drivers of DOC change in the Thames basin (UK). We show that 90% of the long-term rise in fluvial DOC is explained by increased urbanization, which released to the river 671 kt C over the entire period. This source of carbon is linked to rising population, due to increased sewage effluent. Soil disturbance from land use change explained shorter-term fluvial responses. The largest land use disturbance was during the Second World War, when almost half the grassland area in the catchment was converted into arable land, which released 45 kt C from soils to the river. Carbon that had built up in soils over decades was released to the river in only a few years. Our work suggests that widespread population growth may have a greater influence on fluvial DOC trends than previously thought.

Original languageEnglish
Pages (from-to)947-965
Number of pages19
JournalJournal of Geophysical Research: Biogeosciences
Issue number4
Early online date28 Apr 2017
Publication statusPublished - 28 Apr 2017

Structured keywords

  • Water and Environmental Engineering


  • dissolved organic carbon
  • urbanization
  • land use change
  • Thames basin
  • long-term trend


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