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 22, 2012

Troubleshoot-ology: The Study of Problem-Solving


 Bayley with the gas chromatograph and hydrogen generator
Troubleshooting, as we have quickly learned in our time in Iceland, is a very important part of research.  It is indeed a 'search' with many challenges that require innovation and creativity, and  we are continually thinking through the best way to approach our research questions and finding that we must modify equipment, invent new designs, and rethink our plans to best suit what we see in the field.  There are a myriad of variables to constantly consider, in addition to the unexpected things that can pop up at any moment.  We began our trip with power issues with a few essential pieces of equipment - the hydrogen generator and the gas chromatograph.  Once we were able to move into a different lab, we experienced some trouble getting the gas chromatograph to communicate with a computer. But, after reading and re-reading the fine print for our software driver installation, we were able to get the technology to work for us. We also went into the field with Dr. Jim Hood, the postdoctoral research associate in charge of the field project here in Iceland, to learn the particular methods that the group has been using to make metabolism measurements. It is important that we maintain as many methodological similarities across research teams as possible so we can effectively share the data we acquire. To make metabolism measurements for isolated stream substrates, the team is using large gas-tight Plexiglas chambers that seal at the base, with a hole on the top to accommodate a dissolved oxygen (DO) probe. This will allow us to measure the amount of oxygen that is being produced or consumed as a way of evaluating net respiration and photosynthetic rates by a variety of algal and cyanobacterial assemblages found across the study streams.


Dr. Jim Hood showing off the metabolism chamber
These chambers also use a magnetic fan and a stir bar to simulate water flow within the chambers and keep the water circulating throughout the metabolism incubation (another example of creative trouble shooting). This poses a problem with some of our algal samples however, as some species we have encountered are delicate and tend to float at the top of the chamber where the stir bar is spinning.  If the algae are disturbed too much, they may behave differently than they would in the stream. They may also be broken apart, which would potentially cause them to leak out nutrients, such as nitrogen and phosphorous, which we are planning to sample and evaluate in relation to metabolic rates.  The fans may also block some light. Yet, they do a good job of mimicking flow conditions in the stream, so this may present a light versus flow trade-off in terms of replicating natural conditions, and we will have to make some decisions about the magnitude of these trade-offs and what will be most important for our measurements.  At least the chambers maintain consistent conditions across sites and even if light is reduced somewhat, the chamber design will allow for valid comparisons among streams. We are considering modifying our own gas-tight chambers in order to be gentler on the algae. This comes with its own challenges, including modifying the openings to tightly fit the DO probe. This has been an interesting process as well because the materials we are used to working with back in the United States are not always available in Iceland. This has challenged our creative process and ingenuity, and our design has evolved to suit available materials, which has greatly improved our modifications.  
             There are always many things to consider when designing experimental methods, which is not always apparent within the context of a classroom or teaching lab.  It is amazing how much effort is put into studying complex ecosystems.  Every step needs to be carefully thought out, and even when you think you have everything figured out, new insights can throw you off course.  I have come to deeply appreciate the scientists before me that have developed the techniques we use frequently in the lab, as well as the professors who design experiments that work with time and resource restraints, while keeping the science exciting. It is amazing to be a part of this process to see how important team work and collaboration really is.  When one person has a moment of defeat, another team member can come in and save the day with an innovative idea. The challenges we are experiencing show just how perseverant and tenacious scientists are, and how rewarding it is to work through the trouble spots and find exciting and creative ways to answer our research questions.  I can't wait to see it all come together, and every day we are one step closer to answering our own questions about this complex watershed. 

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