info:eu-repo/semantics/article
Autochthonous dissolved organic matter potentially fuels methane ebullition from experimental lakes
Fecha
2019-12-01Registro en:
Zhou, Yongqiang; Zhou, Lei; Zhang, Yunlin; Garcia de Souza, Javier Ricardo; Podgorski, David C.; et al.; Autochthonous dissolved organic matter potentially fuels methane ebullition from experimental lakes; Pergamon-Elsevier Science Ltd; Water Research; 166; 115048; 1-12-2019; 1-12
0043-1354
CONICET Digital
CONICET
Autor
Zhou, Yongqiang
Zhou, Lei
Zhang, Yunlin
Garcia de Souza, Javier Ricardo
Podgorski, David C.
Spencer, Robert G. M.
Jeppesen, Erik
Davidson, Thomas A.
Resumen
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 theepisodic 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 experimentaltreatments are low and high nutrients crossed with three temperatures, to investigate thequantity and drivers of CH4 ebullition. The mean CH4 ebullition flux in the high nutrient treatment(41.5 ± 52.3 mg CH4eC m2 d1) mesocosms was significantly larger than in the low nutrient treatment(3.6 ± 5.4 mg CH4eC m2 d1) mesocosms, varying with temperature scenarios. Over eight weeks fromJune 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, dissolvedorganic carbon (DOC), biodegradable DOC, d2H, d18O and d13C-DOC, autochthonous dissolved organicmatter (DOM) fluorescent components, and a fraction of lipids, proteins, and lignins revealed usingultrahigh-resolution mass spectrometry, and a negative relationship between ebullitive CH4 flux and thepercentage volume inhabited of macrophytes. A 24 h laboratory bio-incubation experiment performed atroom temperature (20 ± 2 C) in the dark further revealed a rapid depletion of algal-DOM concurrentwith 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 algalbiomass, and the resultant accumulation algal derived bio-labile DOM potentially drives enhancedoutgassing of ebullitive CH4 from the shallow-lake mesocosms.