Most of the students and PIs are in Moscow, preparing to board their flight home today. Blaize, Erin, Travis and I are in Cherskiy, continuing our research and finishing up our projects.

During my remaining time here, I’m continuing my soil BOD experiments and conducting nutrient limitation experiments. In lakes, rivers and streams, rates of carbon processing are limited by nutrients in the relative minimum. In more relatable terms, it’s possible to think of the nutrients as milk and cookies. As a human, we can only eat so many cookies before we need a glass of milk to wash it down. When you run out of milk, you need to stop eating cookies. Microorganisms operate on a similar principle. As an Arctic microorganism, you can only process so much carbon before you need some nitrogen or phosphorous. When you run out of one of them, you stop processing carbon.

You can conduct experiments to test what macronutrient is in the relative minimum by collecting water in containers and adding some nutrients. Different buckets get different nutrient treatments (only phosphorous, only nitrogen, and both nitrogen and phosphorous), and some buckets get no treatment. Then, you measure aerobic activity to see which buckets process more or less carbon. If more carbon is processed, then the nutrient that was added to the bucket is limiting.

Here in Cherskiy I’m on round three of these experiments. To add an element of excitement, the containers I’m using are 75 L trash cans from town, and there’s incubating on the roof of the lab so they’re exposed to natural weather conditions. We’ll keep you posted on how this and our other experiments go!