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Erik Jeppesen

Autochthonous dissolved organic matter potentially fuels methane ebullition from experimental lakes

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  • Yongqiang Zhou, University of Chinese Academy of Sciences
  • ,
  • Lei Zhou, University of Chinese Academy of Sciences
  • ,
  • Yunlin Zhang, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, University of Chinese Academy of Sciences
  • ,
  • Javier Garcia de Souza, Instituto de Limnología ‘Dr. Raúl A. Ringuelet’ (ILPLA) (UNLP-CONICET), Boulevard 120 y 62, CC 712 La Plata, Provincia de Buenos Aires, Argentina
  • ,
  • David C. Podgorski, University of New Orleans
  • ,
  • Robert G.M. Spencer, Florida State University
  • ,
  • Erik Jeppesen
  • Thomas A. Davidson

Shallow lakes are hotspots for carbon processing and important natural sources of methane (CH4) emission. Ebullitive CH4 flux may constitute the overwhelming majority of total CH4 flux, but the episodic nature of ebullition events makes determining both quantity and the controlling factors challenging. Here we used the world's longest running shallow-lake mesocosm facility, where the experimental treatments are low and high nutrients crossed with three temperatures, to investigate the quantity and drivers of CH4 ebullition. The mean CH4 ebullition flux in the high nutrient treatment (41.5 ± 52.3 mg CH4–C m−2 d−1) mesocosms was significantly larger than in the low nutrient treatment (3.6 ± 5.4 mg CH4–C m−2 d−1) mesocosms, varying with temperature scenarios. Over eight weeks from June to August covered here warming resulted in a weak, but insignificant enhancement of CH4 ebullition. We found significant positive relationships between ebullition and chlorophyll-a, dissolved organic carbon (DOC), biodegradable DOC, δ2H, δ18O and δ13C-DOC, autochthonous dissolved organic matter (DOM) fluorescent components, and a fraction of lipids, proteins, and lignins revealed using ultrahigh-resolution mass spectrometry, and a negative relationship between ebullitive CH4 flux and the percentage volume inhabited of macrophytes. A 24 h laboratory bio-incubation experiment performed at room temperature (20 ± 2 °C) in the dark further revealed a rapid depletion of algal-DOM concurrent with a massive increased CH4 production, whereas soil-derived DOM had a limited effect on CH4 production. We conclude that eutrophication likely induced the loss of macrophytes and increase in algal biomass, and the resultant accumulation algal derived bio-labile DOM potentially drives enhanced outgassing of ebullitive CH4 from the shallow-lake mesocosms.

Original languageEnglish
Article number115048
JournalWater Research
Number of pages12
Publication statusPublished - Dec 2019

Bibliographical note

Copyright © 2019 Elsevier Ltd. All rights reserved.

    Research areas

  • Bio-labile, Chromophoric dissolved organic matter (CDOM), Greenhouse gases, Methane (CH) ebullition, Parallel factor analysis (PARAFAC), Ultrahigh resolution mass spectrometry, Methane (CH4) ebullition, GREENHOUSE-GAS EMISSIONS, FLUORESCENCE SPECTROSCOPY, CARBON, ENVIRONMENTS, QUALITY, PERSISTENCE, MASS-SPECTROMETRY, SHALLOW EUTROPHIC LAKE, TAIHU, ANCIENT

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