I just returned to Boston after the six weeks of travelling. My two weeks in California, filled with conferences and colleagues, was quite different from the intensive and somewhat isolated period spent in India.
First stop was San Diego, where I attended the 44th Meeting of Advanced Global Atmospheric Gases Experiment (AGAGE) Scientists and Cooperating Networks at the Scripps Institute of Oceanography in La Jolla. Anita Ganesan’s instrument in Darjeeling may pave the way for the first AGAGE site in India, so the crowd was eager to hear her describe our success in deploying her instrument. Her dedicated and diligent work is paying off as she is collecting some of the first high precision direct greenhouse gas measurements in India.
I gave a talk at the AGAGE meeting on my recent work on the flux of H2, CO2 and COS between the soil and atmosphere at Harvard Forest. I focus on the persistence of soil-atmosphere exchange of trace gases across snowpack, which insulates the soil microbial community from freezing air temperatures while allowing trace gases to diffuse through the porous snow matrix. I’m interested in how strongly the biogeochemical cycling continues throughout the winter and in comparing the behavior of the different cycles in the low temperature ‘incubator’ beneath the snow.
This is also the subject of the poster I presented at the American Geophysical Union (AGU) Fall meeting. AGU, with its 20,000+ attendees, was overwhelming, but very enjoyable this year. I met great people and I learned a lot – some connected to my research, some completely random and fun.
I enjoyed both presentations and was happy to get feedback on the project. I was happy to discover the large interest the COS, carbonyl sulfide, community has in my H2 measurements. I have been working closely with Roisin Commane, a postdoc with Steve Wofsy at Harvard, to understand the relationship between the soil sinks of H2 and COS because we have observed a strong correlation between the two. COS has high potential to be used as a tracer of photosynthesis because it is taken up by the photosynthetic machinery of plants, but unlike CO2, it is not re-released by respiration. The respiratory release of CO2 makes partitioning out the photosynthetic component from bulk changes in CO2 very difficult. COS can be used as a tracer of just photosynthesis provided it does not have any other strong production or loss processes. However, COS has a soil sink, and recent observations suggest it may be too large and complex to ignore completely. Roisin and I are hoping to address this with our measurements and to provide information for modellers who investigate this question on larger scales.