Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Discussion papers
https://doi.org/10.5194/bg-2020-21
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-2020-21
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Submitted as: research article 04 Feb 2020

Submitted as: research article | 04 Feb 2020

Review status
This preprint is currently under review for the journal BG.

Dissolved CH4 coupled to Photosynthetic Picoeukaryotes in Oxic Waters and Cumulative Chlorophyll-a in Anoxia

Elizabeth León-Palmero1, Alba Contreras-Ruiz1, Ana Sierra2, Rafael Morales-Baquero1, and Isabel Reche1,3 Elizabeth León-Palmero et al.
  • 1Instituto del Agua and Departamento de Ecología, Universidad de Granada, Granada, 18071, Spain
  • 2Departamento de Química-Física and Instituto Universitario de Investigación Marina (INMAR), Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Puerto Real, 11510, Cádiz, Spain
  • 3Research Unit Modeling Nature (MNat), Universidad de Granada, Granada, 18071, Spain

Abstract. CH4 emissions from reservoirs are responsible for the majority of the atmospheric climatic forcing of these aquatic ecosystems, comparable to emissions from paddies or biomass burning. Primarily, CH4 is produced during the anaerobic mineralization of organic carbon in the anoxic sediments by methanogenic archaea. However, the origin of the recurrent and ubiquitous CH4 supersaturation in oxic waters (i.e., methane paradox) is still controversial. Here, we determined the dissolved CH4 concentration in the water column of twelve reservoirs during the summer stratification and the winter mixing. We obtained that the dissolved CH4 concentration varied up to four orders of magnitude (0.02–213.64 μM), and all depths were consistently supersaturated (710–7082234 %) in both periods. Phytoplanktonic sources of carbon appear to determine the concentration of CH4 in the reservoirs. In the anoxic waters, the depth-cumulative chlorophyll-a concentration, a proxy for the total phytoplanktonic biomass exported to sediments, determined the CH4 concentration. In the oxic waters, the photosynthetic picoeukaryotes abundance significantly determined the dissolved CH4 concentration both during the stratification and the mixing. The mean depth of the reservoirs, as a surrogate of the CH4 transport from sediment to the oxic waters, also contributed in shallow systems. Our findings suggest that photosynthetic picoeukaryotes can have a significant role in determining the CH4 concentration in oxic waters and, in comparison to cyanobacteria, have been poorly explored as CH4 sources.

Elizabeth León-Palmero et al.

Interactive discussion

Status: open (until 17 Mar 2020)
Status: open (until 17 Mar 2020)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
[Subscribe to comment alert] Printer-friendly Version - Printer-friendly version Supplement - Supplement

Elizabeth León-Palmero et al.

Elizabeth León-Palmero et al.

Viewed

Total article views: 187 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
138 44 5 187 20 0 0
  • HTML: 138
  • PDF: 44
  • XML: 5
  • Total: 187
  • Supplement: 20
  • BibTeX: 0
  • EndNote: 0
Views and downloads (calculated since 04 Feb 2020)
Cumulative views and downloads (calculated since 04 Feb 2020)

Viewed (geographical distribution)

Total article views: 145 (including HTML, PDF, and XML) Thereof 145 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 

Cited

Saved

No saved metrics found.

Discussed

No discussed metrics found.
Latest update: 25 Feb 2020
Publications Copernicus
Download
Short summary
CH4 emissions from reservoirs are responsible for the majority of the climatic forcing of these ecosystems. The origin of the recurrent CH4 supersaturation in oxic waters is still controversial. We obtained that the dissolved CH4 concentration varied up to four orders of magnitude in the water column of twelve reservoirs and were consistently supersaturated. Our findings suggest that photosynthetic picoeukaryotes can have a significant role in determining CH4 concentration in oxic waters.
CH4 emissions from reservoirs are responsible for the majority of the climatic forcing of these...
Citation