Identification of hidden underwater methane hotspots with drones

The overall aim of this project is to develop a detection and measurement tool which will be used to obtain good and fast estimates of the methane emissions from fibrous-contaminated sediments (fiberbanks and fiber-rich sediments) in Sweden. To achieve this aim, the project will:

Objective 1.Develop an efficient technique to measure methane fluxes from fiberbanks to the atmosphere through a calibration at two well-characterised sites with the help of a drone equipped with a methane sensor

Objective 2.Further use this technique to identify other sites contaminated with fibrous sediments in Sweden and measure their methane fluxes.

Summary

Fibrous sediments of anthropogenic origin have been identified as a potential threat to biodiversity and human health because of their high contaminant concentrations and also recently as potentially large greenhouse gas (GHG) emitters. When decomposing, the organic fibers that these sediments are mainly composed of create an anoxic environment which leads to the emission of methane. Laboratory tests have shown that the methane production from fiberbanks was higher than rates from other types of sediments (Lehoux et al. 21). However, the amount of methane actually reaching the atmosphere still needs to be measured in the field. To do so, we propose to use a drone equipped with a high-precision methane sensor to survey the emissions at the water surface at two well-characterised sites. Using this measurement as a calibration, this technique will not only allow quantifying the methane emissions from fibrous sediments but also serve as a quick and non-invasive detection technique for fibrous-contaminated sites over the 336 potentially contaminated sites identified by SGU. Identification of these potential methane sources, quantification and listing of the largest emitting sites could be quickly done using this method, allowing adequate remediation actions to take place in order to lower methane emissions and reach the National Environmental Quality Objective of a “limited impact on the climate” and contribute to a climate-neutral society.

Contact: 
Dr Alizée Lehoux, Uppsala University alizee.lehoux@geo.uu.se

Ass. Pr. Erik Sahlée, Uppsala University Erik.Sahlee@met.uu.se

Dr Sarah Josefsson, Geological Survey of Sweden (SGU) sarah.josefsson@sgu.se

Last modified: 2022-06-01