Wednesday, July 30, 2014

Methane and Microbes – What’s Going on?

There has been a lot of discussion about the production of methane from tundra landscapes. This is an important topic since an increased flux of CH4 into the atmosphere related to temperature, hydrology, and disturbance regime could be a positive feedback to global warming. Our NGEE Arctic team has characterized CH4 flux using eddy covariance and chamber-based techniques and our scientists are increasingly confident regarding what the control rates of CH4 emission are across the landscape. What we would like to better understand, however, is how CH4 production is governed by microbial communities in the active layer as it thaws throughout the season.

Mark Conrad (LBNL) traveled to Barrow this past week to study the controls on CH4 flux and hopefully will be able to tease apart some of the many controlling factors with an emphasis on microbially-mediated chemical transformations and pathways. Mark spent the week collecting samples of water from several depths in the soil. Care was taken to pump water from throughout the active layer and preserve those samples for analysis back in the laboratory. This proved to be a long and laborious effort, but by week’s end Mark had many samples for shipment back to his laboratory. There he and his colleagues will analyze a variety of stable isotopes from the samples taken, paying close attention to what the isotopes tell them about the nature and origin of dissolved methane. Mark and others on the NGEE Arctic team would like to quantify the chemical processes that generate methane in soil and thus be able to better understand, and model the flux of CH4 from Arctic tundra.