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Unifying Concepts Linking Dissolved Organic Matter Composition to Persistence in Aquatic Ecosystems.

Anne M KellermanFrançois GuillemetteDavid C PodgorskiGeorge R AikenKenna D ButlerRobert G M Spencer
Published in: Environmental science & technology (2018)
The link between composition and reactivity of dissolved organic matter (DOM) is central to understanding the role aquatic systems play in the global carbon cycle; yet, unifying concepts driving molecular composition have yet to be established. We characterized 37 DOM isolates from diverse aquatic ecosystems, including their stable and radiocarbon isotopes (δ13C-dissolved organic carbon (DOC) and Δ14C-DOC), optical properties (absorbance and fluorescence), and molecular composition (ultrahigh resolution mass spectrometry). Isolates encompassed end-members of allochthonous and autochthonous DOM from sites across the United States, the Pacific Ocean, and Antarctic lakes. Modern Δ14C-DOC and optical properties reflecting increased aromaticity, such as carbon specific UV absorbance at 254 nm (SUVA254), were directly related to polyphenolic and polycyclic aromatic compounds, whereas enriched δ13C-DOC and optical properties reflecting autochthonous end-members were positively correlated to more aliphatic compounds. Furthermore, the two sets of autochthonous end-members (Pacific Ocean and Antarctic lakes) exhibited distinct molecular composition due to differences in extent of degradation. Across all sites and end-members studied, we find a consistent shift in composition with aging, highlighting the persistence of certain biomolecules concurrent with degradation time.
Keyphrases
  • organic matter
  • mass spectrometry
  • risk assessment
  • single molecule
  • climate change
  • high resolution
  • photodynamic therapy
  • squamous cell carcinoma
  • genetic diversity
  • energy transfer
  • drug induced
  • aqueous solution