We are a group of freshwater ecologists from the Biology Department at St. Catherine University in Saint Paul, Minnesota. Our research takes us to Iceland and other arctic regions where we are working to understand how temperature influences nitrogen fixation rates and metabolism in cyanobacterial assemblages. Nitrogen fixation is extremely sensitive to temperature and therefore nitrogen gas from the atmosphere may become more accessible to freshwater ecosystems as the climate warms. We are working to understand the potential ecological and environmental implications of changes in cyanobacteria species composition and nitrogen fixation rates in arctic lakes and streams.

Sunday, July 26, 2015

One small step for ARA, one giant leap for MIMS and N15


Not a bad day to measure nitrogen fixation on stream 9
We did it! Bree, Delor, Jill and I measured nitrogen fixation rates using acetylene reduction assays (ARA), membrane inlet mass spectrometry (MIMS), and N15 assimilation in 5 streams in the Hengill Valley in Iceland this past week.  Bree has a recent blog post that describes the ARA method, so be sure to check it out.  Now, we have added two additional methods to our research.  The days flew by and I learned a lot about each method and the various steps involved. I enjoyed seeing how the methods differ, but also how each one can help us to determine how much nitrogen fixation is really occurring in these streams!  I am excited to see what the results will tell us once we process our samples. Waiting for them will be the hardest part  - even worse than enduring the black flies in the field!

Stream 11 - finished!


 Our task this coming week is to  sample the channel experiment using our three methods once again to measure nitrogen fixation. We will use the same techniques and determination that we had on the natural streams, but in the channel experiment our equipment will be "mini-sized" as we will be sampling from pretty tiny artificial streams - but 30 of them! We are all rested, hydrated, and ready for any weather as we gear up for this next major sampling effort.
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