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-2019-263
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-2019-263
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Submitted as: research article 29 Jul 2019

Submitted as: research article | 29 Jul 2019

Review status
This discussion paper is a preprint. A revision of this manuscript was accepted for the journal Biogeosciences (BG) and is expected to appear here in due course.

Regulation of carbon dioxide and methane in small agricultural reservoirs: Optimizing potential for greenhouse gas uptake

Jackie R. Webb1, Peter R. Leavitt1,2,3, Gavin L. Simpson1,2, Helen Baulch4, Heather A. Haig1, Kyle R. Hodder5, and Kerri Finlay1 Jackie R. Webb et al.
  • 1Department of Biology, University of Regina, Regina, SK, S4S0A2, Canada
  • 2Institute of Environmental Change and Society, University of Regina, Regina, Saskatchewan, S4S 0A2, Canada
  • 3Institute for Global Food Security, Queen's University Belfast, Belfast, Northern Ireland, BT7 1NN, UK
  • 4School of Environment and Sustainability, Global Institute for Water Security, University of Saskatchewan, 11 Innovation Boulevard, Saskatoon, SK S7N3H5, Canada
  • 5Department of Geography & Environmental Studies, University of Regina, Regina, SK, S4S0A2, Canada

Abstract. Small farm reservoirs are abundant in many agricultural regions across the globe and have the potential to be large contributing sources of carbon dioxide (CO2) and methane (CH4) to agricultural landscapes. Compared to natural ponds, these artificial waterbodies remain overlooked in both agricultural greenhouse gas (GHG) inventories and inland water global carbon (C) budgets. Improved understanding of the environmental controls of C emissions from farm reservoirs is required to address and manage their potential importance. Here, we conducted a regional scale survey (~ 235,000 km2) to measure CO2 and CH4 concentrations and diffusive fluxes across 101 small farm reservoirs in Canada's largest agricultural area. A combination of abiotic, biotic, hydromorphologic, and landscape variables were modelled using generalized additive models (GAMs) to identify regulatory mechanisms. We found that CO2 concentration was best estimated by a combination of internal metabolism and groundwater-derived alkalinity (65.7 % deviance explained), while multiple lines of evidence support a positive association between eutrophication and CH4 production (74.1 % deviance explained). Fluxes ranged from −21 to 466 and 0.14 to 92 mmol m−2 d−1 for CO2 and CH4, respectively, with CH4 contributing an average of 74% of CO2-equivalent (CO2-e) emissions. Approximately 19 % farm reservoirs were found to be net CO2-e sinks. From our models, we show that the GHG impact of farm reservoirs can be greatly minimised through overall improvements in water quality and the construction and maintenance of deeper reservoirs.

Jackie R. Webb et al.
Interactive discussion
Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement
Interactive discussion
Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement
Jackie R. Webb et al.
Jackie R. Webb et al.
Viewed  
Total article views: 433 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
352 79 2 433 17 1 2
  • HTML: 352
  • PDF: 79
  • XML: 2
  • Total: 433
  • Supplement: 17
  • BibTeX: 1
  • EndNote: 2
Views and downloads (calculated since 29 Jul 2019)
Cumulative views and downloads (calculated since 29 Jul 2019)
Viewed (geographical distribution)  
Total article views: 361 (including HTML, PDF, and XML) Thereof 355 with geography defined and 6 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Cited  
Saved  
No saved metrics found.
Discussed  
No discussed metrics found.
Latest update: 20 Oct 2019
Publications Copernicus
Download
Short summary
Small farm reservoirs are key features within agricultural landscapes, yet these waterbodies can contribute substantial greenhouse gas (GHG) emissions to the atmosphere. This study assessed some of the environmental factors that may reduce the production of GHGs. We found promise that farm reservoirs can act as net greenhouse gas sinks and identified some of the key water quality, landscape, and design features that may support GHG mitigation.
Small farm reservoirs are key features within agricultural landscapes, yet these waterbodies can...
Citation