Greenhouse Gas Research Stage One: Building Flux Chambers

Summer research down at the Keck lab is off to a busy start, with student projects including everything from turtle research to denitrification polymers. My project involves quantifying the amounts of greenhouse gases (carbon dioxide, methane, and nitrous oxide) being emitted from local ponds and lakes.  While we often associate greenhouse gases with driving cars and generating electricity, some of the more “natural” sources of these gases also have important implications for the global climate.  My goal this summer is to determine how much Lake Matoaka, the Crim Dell, and other ponds on campus contribute to our overall greenhouse gas emissions.

Over the past two weeks, I’ve been re-reading papers on similar studies, learning how to operate the Keck lab’s brand new Greenhouse Gas Analyzer, and building static flux chambers.  While these chambers may sound high-tech, they are actually just made of sawed-off 5-gallon buckets wrapped with kids’ pool noodles and fitted with a valve and fan.

Constructing static flux chambers outside the Keck Lab

Constructing static flux chambers outside the Keck Lab

As simple as they are, these basic chambers are widely-used by researchers to collect gas samples from bodies of water and soils.  As gases bubble up, they become trapped in the chamber and increase in concentration over time.  Taking samples at regular intervals during the sampling time allows for the calculation of a “flux”, or the rate of gas emissions per area per time.  Knowing the flux will allow us to determine the overall greenhouse gas emissions each body of water contributes.

Static flux chamber floating on Lake Matoaka by the Keck Lab dock

Static flux chamber floating on Lake Matoaka by the Keck Lab dock

Aside from building chambers, I’ve also been getting acquainted with the greenhouse gas analyzer.  It lives in it’s own room in the Keck lab, and requires tanks of nitrogen, hydrogen, and pure air to operate.  A representative from Shimadzu, the company that manufactures the analyzer, came down to give us a two day training on how to turn on and off the machine, inject samples, and use the software associated with the analyzer to get our results.  While intimidating at first, the greenhouse gas analyzer is relatively easy to use, gives concentrations of all three greenhouse gases in one run, and can process a new sample every eight minutes!

The greenhouse gas analyzer

The greenhouse gas analyzer

With training sessions behind us and supplies purchased, it’s almost time to begin the data collection part of the project.   Next up I’ll be outfitting the flux chambers with a few last components: a fan to mix the gases inside the chamber and aluminum foil to reflect sunlight and prevent the chamber from heating up while sampling.  Then it’s time to begin sampling, starting with the Keck Lab’s own backyard: Lake Matoaka.  Stay tuned!

 

Comments

  1. kesandberg says:

    Hi Carolina!

    This is so interesting! I knew that natural sources also gave off greenhouse gases, but I never considered measuring those right in our own backyard here at William and Mary! As someone who does not study science, it sound like an intimidating process, so it was so cool to see that all it takes is a few buckets to collect the gases.

    I’m curious to know if the amount of greenhouse gases that these bodies of water give off can be affected by different things like pollution, erosion, temperature, etc.? Obviously the best solution to reducing greenhouse gas emissions would be reducing our own carbon footprint by limiting the amount we engage in activities like driving cars, but if you did find that bodies of water were giving off a large amount of gases, would there be ways that we could reduce the number somehow?

    Looking forward to hearing more about your project! Good luck with the sampling!

  2. carolina says:

    Hi Kate!
    Thanks for reading my blog! Those are great questions, and definitely some things we are still trying to figure out. I’ll be doing experiments for the rest of the summer to determine how some of the other factors you mentioned (like pollution/temperature, etc.) affect emissions, but some previous research suggests that they make a big difference. Check back in in a few months to see what the data says!

    As for how we can reduce the gases coming off large bodies of water, there’s a couple of options that might help. First, a lot of the emissions from bodies of water are driven up by the decomposition of large algae blooms that are fed by nutrient runoff. So it’s likely that controlling nutrient pollution (sewage, runoff from farms, or runoff fertilized lawns) could help bring down aquatic greenhouse gas emissions. Secondly, most of the ponds and lakes in our area are man-made storm water ponds. So considering other storm water options (such as pervious pavement) instead of building new ponds could also be a way to reduce emissions. Since methane has around 30x more “warming potential” than CO2, building ponds in ways that favor the release of carbon dioxide rather than methane could be another strategy. But again, there’s a lot more research that needs to be done to answer those questions fully. I’ll keep you updated!

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