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Listen carefully for the bubble!

Hey Hey Everyone! I’ve been given this opportunity to tell you a little bit more about my project. I spent the first month of this program building my sensors in Dr. Ruth Varner’s lab at the University of New Hampshire. I really like building things so I was happy to rise to the challenge of combining the designs of the peat sensors and the lake sensors in order to build an effective thaw pond sensor. These thaw pond sensors had to be smaller than the lake sensors because the thaw ponds were much shallower than the lakes so the sensor had to be light enough so that the whole sensor wouldn’t sink but it could be below the water table enough that the hydrophone would be fully submerged. I eventually came up with a design that is smaller and lighter than the current lake sensors. One of the issues I was pondering over in the building phase was how was I going to install the sensors into the ponds and have them remain upright in the water?  When I went to the Stordalen mire with Dr. Varner and we figured out a way to ensure the sensors would stay upright in the water by using PVC piping with buoyant Styrofoam pieces on them, and then attaching the sensors to the piping. It seems to be working fine so far!

These sensors have been sampled almost everyday since they were installed and I have been able to run these gas sampled on the Gas Chromatograph here at Abisko in order to calculate the concentration of each volume of gas I sampled. There are six peat sensors that I also installed when we first arrived in Abisko. These sensors were deployed in areas close to the thaw pond sensors, but these sensors are measuring ebullition events occurring in the peat (hence the name). Since the peat remains colder for longer, we have yet to see any measurable methane flux captured in these sensors.

Deploying the sensors in the field in Stordalen Mire.  Sophie Burke.

The peat will warm up enough to see any ebullition events later in the summer and will keep producing methane later in the season than the thaw ponds and lakes because as it remains colder longer at the beginning of summer it also stays warmer longer at the end. Since the peat sensor excitement will be most likely occurring after I leave Abisko Dr. Varner has asked Dr. McCalley, a post-doc working at Abisko to sample the peat sensors and thaw pond sensors after we leave. Another exciting thing associated with Dr. McCalley is that she will be running the samples she collects for us on a Quantum Cascade Laser (QCL), which detects what isotopes of methane are present within these ebullition samples. This is very new technology with a new application, which makes it all very exciting!

Two of the six pond sensors successfully deployed  in Stordalen Mire.      Sophie Burke.

Based on the thaw pond samples I have successfully run through the GC here at Abisko, I have found that the thaw ponds samples contain between 10% and 30% methane. Considering I am sampling these sensors generally every other day, this is a significant amount. Lately though, Abisko has experienced a rather extreme weather event which resulted in an incredibly amount of rainfall. This has resulted in the mire water table to rise significantly.  An increase in water table effects the rate of ebullition from the thaw ponds, and I think over the next few days as the water table begins to fall I will be able to see a change in the methane flux collected by the sensors.

 

-Sophie

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