Limitations on using CDOM as a proxy for DOC in temperate lakes

Claire G. Griffin, Jacques C Finlay, Patrick L. Brezonik, Leif Olmanson, Raymond M Hozalski

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

Colored dissolved organic matter (CDOM) has been widely studied as part of efforts to improve understanding of the aquatic carbon cycle, by laboratory, in situ, and remote sensing methods. We studied ecoregion-scale differences in CDOM and dissolved organic carbon (DOC) to understand variability in organic matter composition and the use of CDOM as a proxy for DOC. Data from 299 lakes across the U.S. Upper Midwest showed that CDOM, measured as absorptivity at 440 nm (a440), correlated strongly with DOC (R2 = 0.81, n = 412). Colored lakes in the Northern Lakes and Forests (NLF) ecoregion drove this relationship. Lakes in the North Central Hardwood Forests (NCHF) had low color (most had a440 < 3 m−1) and weaker CDOM-DOC relationships (R2 = 0.47). Spectral slopes and specific ultraviolet absorbance (SUVA), indicated relatively low aromaticity and non-terrestrial DOM sources in low color lakes. Multiple regression analyses that included total dissolved nitrogen (TDN) and CDOM, but not chlorophyll a, improved DOC estimates in low color lakes, suggesting a dominant contribution of non-planktonic sources of low color DOM in these lakes. Our results show that CDOM is a reliable, regional proxy for DOC in lakes where forests and wetlands dominate the landscape and the DOM is primarily terrestrial in origin. Mapping of lake DOC at broad spatial scales by satellite-derived CDOM has lower accuracy in low color lakes.

Original languageEnglish (US)
Pages (from-to)719-727
Number of pages9
JournalWater Research
Volume144
DOIs
StatePublished - Nov 1 2018

Bibliographical note

Funding Information:
The authors thank the United States National Science Foundation (Divisio of Chemical, Bioengineering, Environmental, and Transport Systems #1510332); the Minnesota Environment and Natural Resources Trust Fund, United States; the University of Minnesota Office of the Vice President of Research, United States; the University of Minnesota Retirees Association, United States; and the University of Minnesota U-Spatial Program, United States for funding this work. We thank Michelle Rorer and many other members of the Finlay lab for their help collecting and analyzing water quality samples. Thanks to Drs. Marvin Bauer, William Arnold, and Yiling Chen whose feedback and input to our work examining CDOM in Midwestern lakes has been valuable.

Funding Information:
The authors thank the United States National Science Foundation (Divisio of Chemical, Bioengineering, Environmental, and Transport Systems # 1510332 ); the Minnesota Environment and Natural Resources Trust Fund , United States; the University of Minnesota Office of the Vice President of Research, United States ; the University of Minnesota Retirees Association, United States ; and the University of Minnesota U-Spatial Program, United States for funding this work. We thank Michelle Rorer and many other members of the Finlay lab for their help collecting and analyzing water quality samples. Thanks to Drs. Marvin Bauer, William Arnold, and Yiling Chen whose feedback and input to our work examining CDOM in Midwestern lakes has been valuable.

Publisher Copyright:
© 2018 Elsevier Ltd

Keywords

  • Aquatic carbon cycle
  • Colored dissolved organic matter
  • Dissolved organic carbon
  • Lakes

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