Another method of collecting data on the effects of warming tundra soils is the Snow Pit Method. The overall technique has been around longer than the Fences Method designed by Ted Schuur and Sue Natali. At CiPEHR the idea for using snow pits was conceived by Dr. Ted Schuur. These pits were then constructed by Dr. Sue Natali.
Basically, a hole is dug in a measured depth of snow to the tundra below. A very accurate measurement is then taken of CO2 emissions from a specific area of tundra. Because snow insulates the tundra beneath this allow for a comparison between snow depth and CO2 emissions. At the Snow Pit Site Research Elizabeth Webb also measures soil temperature and moisture.
Panorama of Snow Pit area on the CiPEHR site. John Krapek (Field Tech.) next to the LI-COR and Elizabeth Webb (Researcher) standing with shovel.
Here I am sampling CO2 emissions at the Snow Pit site. The LI-COR with timer is in the foreground with a field notebook in which I record data. Smiley is in the hole.
The snow pit method at CiPEHR Site involves an area with ten different plots. Each of these plots has four sample points. At each of these points (marked with wooden stakes) is a 12” round 6” tall piece of PVC pipe buried in the tundra with 1” of the lip exposed above ground. A special cap was constructed to fit over this lip (we call this cap, Smiley). This cap is fitted over the lip of the PVC pipe exposed above ground. It is connected to the LI-COR CO2 sampler. The LI-COR samples the amount of CO2 produced over a 2 minute period.
The Snow Pit site at CiPEHR. Field Tech. John Krapek is standing with a shovel. You can see the different plots scattered around the site marked with stakes.
The Process: First the snow depth is measured at the sample point, each stake, is labeled A, B, C, or D then measured at the center of the plot.
One of ten different plots at the Snow Pit site on CiPEHR. Each stake marks a PVC pipe buried in the tundra.
Next a pit is dug in the snow at the sample point to be tested that day to expose the PVC pipe buried in the tundra.
A pit in the snow has been dug at one of the sample stakes at a plot on the snow pit site at CiPEHR.
The PVC embedded in the tundra exposed at the bottom of the snow pit.
The cap (Smiley) connected to the LI-COR is place over the exposed lip of the buried PVC pipe. Care must be taken not to breath in the snow pit while doing this otherwise the LI-COR will be measuring your CO2 exhalation rather than the CO2 emission from the soil. This is easier said than done considering some of the pits are more than 3’ deep. The cap does not always fit smoothly so as a result placing the cap may require you to hold your breath for a considerable amount of time.
Here I am shown preparing to enter the snow pit with Smiley in hand. In the foreground is the LI-COR with the timing mechanism on top.
Here I am holding my breath as I place the cap on the exposed PVC pipe at the bottom of the snow pit.
The start button and 2-minute timer buttons are pushed on the recorder attached to the LI-COR and a sample is taken. Afterward the snow pit is filled back in.
Here I am sampling CO2 with the LI-COR and timer. I'm checking to make sure it is recording data.
CO2 emission data at each plot is then compared to snow depth (each sample plot is at a different depth). This data allows Researcher Elizabeth Webb the ability to compare how snow depth relates to CO2 emission from tundra.
Here I am with Researcher Elizabeth Webb at a demonstration she conducted at PolarTREC Orientation Week in Fairbanks, AK. I am holding the cap used to collect CO2 emissions from the snow pits. Now, you see why it's called Smiley:)