Unifying concepts linking dissolved organic matter composition to persistence in aquatic ecosystems

Environmental Science & Technology
By: , and 

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Abstract

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.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Unifying concepts linking dissolved organic matter composition to persistence in aquatic ecosystems
Series title Environmental Science & Technology
DOI 10.1021/acs.est.7b05513
Volume 52
Issue 5
Year Published 2018
Language English
Publisher ACS
Contributing office(s) National Research Program - Central Branch
Description 11 p.
First page 2538
Last page 2548