Shedding new light on emissions in the Amazon
Field measurements of biosphere-atmosphere gas exchange processes are important because they provide a clear mechanism to study greenhouse gas dynamics in detail. The Amazon rainforest with its significant wetlands is considered a key region for tropical methane emissions.
“As a major greenhouse gas, understanding the source, concentration and flux levels of methane is integral to evaluating its impact on the Amazon ecosystem both in the short and long term,” said Dr van Asperen.
“Until now, most of the focus for greenhouse gas studies in the Amazon has been on CO2. There is a gap in awareness of methane in the region, but using the SpectronusTM we are in the position to extend our knowledge on methane production, this will improve our overall understanding about the ecosystem methane processes. The fact that we can measure both concentration and flux of multiple pollutants makes the data we receive even more valuable,” she added.
After securing funding, in August 2018, Dr van Asperen moved to Manaus, Brazil to begin her research project working in conjunction with Brazil’s INPA – National Institute of Amazon Researches. She installed one of the University of Bremen’s SpectronusTM analysers at the K34-tower, a 51-metre high flux tower that sits high in the tree canopy at field site ZF2 near Manaus. To complement her SpectronusTM continuous measurements, Dr van Asperen also measured local soil, tree and termite emissions with a flux chamber and a portable instrument.
Satellite imagery had indicated heavy methane concentrations over the area with strong peaks, so Dr van Asperen began testing the theory that they may be related to the waterlogged valleys, which are abundant in the Amazon rainforest.
Dr Hella van Asperen presented the preliminary findings of her two-year research project at EGU 2020, the annual General Assembly of Europe’s leading organisation for earth, planetary and space science research. The virtual presentation, entitled Tropical forest CH4 : from flux chambers to micrometeorological tower measurements outlined Dr van Asperen’s conclusions regarding overall ecosystem emissions of Methane (CH4), Carbon dioxide (CO2) as well as Nitrous oxide (N2O).
Methane peaks didn’t correlate with rain or temperature patterns however, they did sometimes coincide with CO peaks, possibly indicating an anthropogenic origin. Dr van Asperen is currently working on a paper that will publish the full project results.