Production of Black Carbon-like and Aliphatic Molecules from Terrestrial Dissolved Organic Matter in the Presence of Sunlight and Iron

Hongmei Chen, Hussain A.N. Abdulla, Rebecca L. Sanders, Satish Chandra Babu Myneni, Kenneth Mopper, Patrick G. Hatcher

Research output: Contribution to journalArticle

45 Scopus citations

Abstract

Photochemical processing of dissolved organic matter (DOM) in natural waters can alter its composition and structure, supply particulate organic matter (POM) to sediments, and deliver modified terrestrial DOM to the ocean. Our studies show that terrestrial DOM exposed to simulated sunlight is altered to produce POM with a markedly different molecular composition enriched with newly formed aliphatic and condensed aromatic molecules. This process is closely tied to the chemistry of iron, which primarily exists as dissolved Fe(II) and Fe(III)-organic complexes in initial DOM and photochemically matures to Fe(III) oxyhydroxides before coprecipitating out with POM. The newly formed condensed aromatic compounds resemble black carbon, which until now was thought to be produced by only combustion. These new molecules contribute a pool of Fe-rich, aliphatic, and black carbon-like organic matter to sediments as the terrestrial DOM is transported through rivers. We estimate that the annual global flux of this photoproduced black carbon, most of which may be preserved in sediments, is nearly equivalent to the estimated flux of dissolved black carbon to the ocean from all other sources.

Original languageEnglish (US)
Pages (from-to)399-404
Number of pages6
JournalEnvironmental Science and Technology Letters
Volume1
Issue number10
DOIs
StatePublished - Sep 24 2014

All Science Journal Classification (ASJC) codes

  • Environmental Chemistry
  • Ecology
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis

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