Consequences of intense drought on CO2 and CH4 fluxes of the reed ecosystem at Lake Neusiedl

Pamela Alessandra Baur (Corresponding author), Andreas Maier, Claudia Buchsteiner, Thomas Zechmeister, Stephan Glatzel

Publications: Contribution to journalArticlePeer Reviewed

Abstract

Reed (Phragmites australis) dominated wetlands are commonly known as strong carbon (C) sinks due to the high productivity of the reed plant and C fixation in the wetland soil. However, little is known about the effects of drought on reed-dominated wetlands and the possibility of Pannonian reed ecosystems being a source of greenhouse gases (GHG). The drought at Lake Neusiedl had a particular impact on the water level, but also had consequences for the reed belt. Therefore, we investigated the drought-influenced C fluxes and their drivers in the reed ecosystem of this subsaline lake over a period of 4.5 years (mid-2018 to 2022). We applied eddy covariance technique to continuously quantify the vertical turbulent GHG exchange between reed belt & atmosphere and usedvegetation indices to account for reed growth. Methane emissions decreased by 76% from 9.2 g CH 4-C m -2a -1 (2019) to 2.2 g CH 4-C m -2 a -1 (2022), which can be explained by the falling water level, the associated drying out of the reed belt and its consequences. Carbon dioxide emissions initially decreased by 85% from 181 g CO 2-C m -2 a -1 (2019) to 27 g CO 2-C m -2 a -1 (2021), but then increased to twice the 2019 level in 2022 (391 g CO 2-C m -2 a -1). Due to the drying reed belt, the reed initially grew into formerly water-covered areas within the reed belt, especially in 2021, leading to higher photosynthesis through 2021. This development stopped and even reversed in 2022 as a consequence of the sharp decrease in sediment water content from about 65 to 32 Vol-% in mid-2022. Overall, drought led to a decoupling of the reed ecosystem from the open lake area and developed the wetland into a strong C source.

Original languageEnglish
Article number119907
JournalEnvironmental Research
Volume262
Issue number2
DOIs
Publication statusPublished - 1 Dec 2024

Austrian Fields of Science 2012

  • 105205 Climate change
  • 106026 Ecosystem research
  • 105904 Environmental research
  • 105405 Geoecology

Keywords

  • eddy covariance
  • Phragmites australis
  • wetland
  • Greenhouse gas emission
  • shallow lake
  • subsaline
  • reed
  • CH4 fluxes
  • CO2 fluxes
  • LTER
  • drought
  • Subsaline
  • Eddy covariance
  • Shallow lake
  • Wetland

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