Uncovering methane sources in the Amazon with the Acoem Spectronus
22 Oct 2020
Dr Hella van Asperen from the Institute of Environmental Physics at the University of Bremen (Germany) in the Amazon Rainforest, Brazil
By Charis Heelan, Acoem Senior Copywriter
SpectronusTM – one of the first multispecies greenhouse and other atmospheric trace gas and isotope analyser based on Fourier Transform infrared (FTIR) spectroscopy – is the only instrument capable of measuring both concentration levels of Carbon dioxide (CO2), Methane (CH4), Nitrous oxide (N2O), Carbon monoxide (CO) and Delta13 CO2 simultaneously for ecosystem research.
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.
The effect of fires on the Amazon ecosystem
Although not a direct focus of Dr van Asperen’s research study, forest fires burning in the Amazon both currently and in 2019 have had a huge impact on the carbon monoxide readings in the region.
The SpectronusTM has detected extraordinary levels of CO over the last few months, coinciding in what has been deemed the most catastrophic year for fires in Brazil. Preliminary data collected by the National Spatial Research Institute (INPE) indicated that there were 29,307 fires in the Brazilian Amazon in August 2020 alone. In the first week of September 2020 there were more than double the number of fires than in the same period for 2019.
Continuing SpectronusTM research in the Amazon
Depending on ongoing COVID-19 pandemic conditions, Dr van Asperen plans to de-commission the SpectronusTM from its current location on Tower K34 in early 2021 and install it on a boat to form the basis of a research expedition down the Rio Negro to measure methane concentrations and fluxes on water.
A second SpectronusTM is also due to be installed early next year at the Amazon Tall Tower Observatory (ATTO) located only a few kilometres from Dr van Asperen’s site. The ATTO project aims to learn more about biogeochemical cycles (such as the carbon cycle), the water cycle and energy fluxes in the Amazon, and determine their impact on global climate and how they are influenced by climate change.
Closing a gap in the global climate monitoring network, it is hoped that the findings from SpectronusTM and the Observatory will improve climate prediction models and highlight the critical role that the Amazon plays in the global climate system.
Global Applications of FTIR Spectroscopy
The SpectronusTM continues to be a choice analyser for researchers around the world. Last year, it became only the third ever instrument to be approved by the Integrated Carbon Observation System (ICOS) as a compliant greenhouse gas (GHG) analyser.
It offers ease of measurement for a variety of applications including tall tower, N2O soil flux, water CH4 and continuous, long-term, unattended stations. SpectronusTM can also control a complete air quality monitoring system and log metrological sensor data to obtain a wholistic view of the environment’s atmospheric conditions