Soil respiration

Yesterday we had some very nice weather! It was foggy and misty, but there was no rain and very little wind. Antarctica is a very windy continent, and that's especially true here on King George Island in January! Most days when we've been out working, we have worked through 20-40 mph gusts. Yesterday was much calmer, and we took advantage of the nice day to measure some CO₂ flux.

For our research, we are interested in measuring how plants influence the soil biological community. We look at the biological community in different ways. One way is by measuring how active they are. All of the organisms in the soil, from the tiny bacteria to the larger Collembola, all have to respire in order to live. This is how they break down their food to release energy that they need to function. Most organisms in the soil use oxygen and respire carbon dioxide, just like humans! We also breathe in oxygen and respire carbon dioxide. And, when we are more active, we breathe more. You breathe more heavily when you are getting exercise than you do when you are sitting still watching TV. So, the amount of carbon dioxide that you are producing corresponds to how active you are.

We use the same principle to measure the soil community. We measure how much CO₂ is being produced from the soil. If more CO₂ is coming from the soil, it tells us that there is a more active soil community. They are probably more abundant, and eating and metabolizing more!

We measure the amount of CO₂ being produced by the soil using an infrared gas analyzer, which is on the ground in front of Dr. Hannah. The gray chamber in Dr. Hannah's hand gets placed on top of a PVC ring, which directs the CO₂ coming from the soil up into the chamber. The gas is then pumped through the black hoses from the chamber into the blue-and-gray machine. The machine contains the gas analyzer that measures the rate of CO₂ being produced. 

While Dr. Hannah and I used the gas analyzer, Zoie ran around placing the PVC rings for the next samples. (That's why she's off in the distance to the right.) So Zoie kept us moving forward to the next sample until we were done!

We measured how much respiration was being produced by the soils at each of our successional zones. We'll be able to compare whether soils beneath certain plants are more active in early, mid, or late succession stages. But, analyzing all of that data takes a LONG TIME, so I'll have to tell you the answer later!