We are a group of freshwater ecologists from the Biology Department at St. Catherine University in Saint Paul, Minnesota studying the effect of temperature and nutrient availability on metabolism and nitrogen fixation in geothermally active streams in the Hengill region of Iceland. This is a collaborative research effort with our partners from Montana State University, the University of Alabama, the University of Iceland, and the Institute of Freshwater Fisheries in Iceland. See links to our collaborators labs below.
Thursday, September 19, 2013
One of the most rewarding experiences that I had this summer was the opportunity to design my own experiment and take charge of all of the details. Curiosity drives research, so I had to first ask myself, what am I curious about? After the course of a couple weeks in the field using three methods to measure nitrogen fixation, I asked myself, why can’t we use just one method, or what are the advantages and disadvantages of each method, and what can we understand better that will convince us of the accuracy of these methods? Then, I had to devise an array of field measurements using each of our methods that would provide some insight into where the discrepancies between the methods lies. The first day that I was in charge of the field team, I was running on adrenaline, not knowing what the results would reveal, or how the day would go.
Friday, September 6, 2013
|Thumbs up for science!|
|One of the final times working with these chambers. |
Oh, how I miss them!
Wednesday, July 24, 2013
|When using 3 methods to |
estimate nitrogen fixation, time and
organization of the essence -
and I made sure to keep us on task.
|Here, Jill and I are adding 15N2 gas (contained in|
the small gray cylinder) to our chambers containing
algae from the different temperature treatments.
|It is definitely a coordinated team effort to get all of our|
various chambers set up and running - and in the rain!!
|It's working! Yes!|
So at the end of the day we had spent 10 hours in the field and we were exhausted, but excited to have completed an exceptionally successful day in the field. At the end of the day, I found it to be very satisfying to know that everything that we worked so hard on up to this day had paid off. And, just wait until you see the data - they are very exciting!! But, just like the journey of Harry Potter, not all can be revealed at once. You must wait until the full story unfolds...all in good time.
Sunday, July 21, 2013
|"Rock" Nostoc - Nostoc c.f. pruniforme|
|"Pink" Nostoc - Nostoc spongiaeforme|
Sunday, July 7, 2013
|We found algae!|
This summer we are planning to measure nitrogen fixation with three different approaches as a comparison of the methods, as well as to use them as a check against each other. For
|Chemical conversion of nitrogen fixation (left) and |
how it compares to acetylene reduction (right).
|Working on getting "the" number.|
So far, our research has been really frustrating, impossibly complicated, and infinitely
|Excited after a day in the field of |
hiking and looking at algae.
Friday, July 5, 2013
|The 300mL chamber that will be used|
to measure nitrogen fixation
Several hours of critical thinking mixed with trial and error resulted in these problems being solved. At the end of the day, it is extremely gratifying to have created a solution to a problem that at the beginning of the day seemed unfix-able. These challenges have helped me to understand that critical thinking and creativity go hand in hand during research.
Tuesday, June 25, 2013
|Jill, Jackie, Aimee, Allison, Mara, Kyrstin & Anika|
|Sunset over Greenland|
Since we have been here for several days now, I have had a chance to see more of the unique landscape of Iceland. The island is geologically young and was formed from volcanic eruptions from a giant volcanic hot spot that sits on the ridge of the Eurasian and American tectonic plates, which are constantly moving away from each other. This volcanic island has geothermally-heated pools and streams that are naturally warmed as water flows underground through heated rock, warming the water before it emerges at the ground surface. Iceland is also located close to the Arctic Circle, with the capitol Reykjavík positioned at a latitude of 66° north, where it does not get very warm, even during the summer. At this high latitude, Iceland experiences incredibly long days during the summer months and even though the sun sets for a couple hours, it never gets truly dark. This midnight sun allows the locals to take advantage of being outside as much as possible.
Iceland is certainly also a very unique place to study from an ecological standpoint. Since the island is so young, the volcanic basalt is very phosphorus-rich, suggesting that the growth of many organisms here is not limited by available phosphorus (an essential nutrient for growth), but instead constrained by a lack of available nitrogen – another essential nutrient. This provides a good environment for researching nitrogen fixers, which are bacteria that can acquire
|Fields of lupine cover the hillslopes within the city and|
surrounding area, all along our drive to the field site.
Monday, June 24, 2013
|The kitchen Jackie and I share|
It is not difficult to get around Reykjavík by biking or walking, which helps reduce the amount of waste within the city. Even the garbage cans are smaller here, which helps you recognize just how much you are throwing away. It appears that the choice to be more efficient is collective in Iceland; it’s a way of life not a lifestyle. The idea of preserving the landscape and reducing environmental changes is deeply embedded in Icelandic society. It is a huge shock to be immersed in a culture where “less” does not mean less quality, it is simply less wasteful.
It is common to hear conversations about reducing waste and terrain conservation, but rarely do you hear about a place where these two ideas are actually carried out. Living in the United States, where the population is large, it can be difficult to believe that one person’s choice to be more eco-friendly will have an impact. It is wonderful to be in a country where this actually happens. Witnessing a country that successfully incorporates these two ideas into its society has changed my perspective on the likelihood that the same can be done holistically in the United States.
Friday, June 21, 2013
|Experimental channels with 5 temperature treatments - |
ambient, +5, +10, +15, +20 degrees C.
Three channels are maintained at each temperature.
|Close up of basalt |
tiles in the channels
|First field day measuring metabolic rates associated|
with algae and microbes that have colonized the tiles
after 4 weeks. It was quite rainy and windy!
We arrived just before the first sampling period, scheduled for 4 weeks after Tanner had placed clean basalt tiles into the channels to provide a colonization surface for the resident algae and microbial community. Upon inspection you could see that the tiles were beginning to turn green, with a visible effect of the temperature treatments, so it was time to collect the first initial set of data. Our first planned field day was canceled due to bad weather, which has to be pretty bad to cancel a field day (it was very foggy with low visibility and lots of rain), but we have been out in the field for the past 3 days now and we been fortunate to have sunny skies for the most part. The first day we measured photosynthesis and cellular respiration on sets of tiles from each of the experimental channels, followed by nutrient uptake (both nitrogen and phosphorus) yesterday and today. It has simply been beautiful out - so nice in fact, that one might be tempted to think that you no longer need to bring heavy rain gear to the field. Ah....but one should never give in to such thoughts at Hengill, as sunny skies can turn to cold wind and heavy rain in a blink of an eye!
|Beautiful sunny day with
Ellie, Tanner, Jill, Aimee,|
David and Jackie. Tile sampling, day 2.
Monday, June 17, 2013
|View of the edge of Greenland from the flight |
to Iceland. Photo by Jackie Goldschmidt.
|Arrival at Keflavik Airport|
|The St. Kate's Crew at the Society for Freshwater Science conference - left |
to right - Paula Furey, Delor Sander (standing), Jill Welter, and Anika Bratt
|Delor presenting her poster at SFS - pictured here with|
J.S. Ólafsson and G.M. Gíslason - our collaborators from Iceland,
and Jim Hood from Montana State U. (left to right).
Delor Sander et al. "Predicting effects of climate warming on N2-fixation and its ecological consequences in aquatic ecosystems: a comparison of acetylene reduction and 15N2 isotopic methods"
Jill Welter et al. - "Effect of temperature on N2-fixation rates and N2-fixer species assemblages in streams in the Hengill region of Iceland"
Paula Furey et al. - "Composition and abundance of nitrogen-fixing algal assemblages in nitrogen-limited streams along a geothermal gradient in the Hengill region of Iceland"
Jim Hood et al. - "Patterns of nitrogen and phosphorus uptake across a thermal gradient of subarctic streams"
Jim Junker et al. - "Patterns of epilithic CNP stoichiometry across a natural temperature gradient in Icelandic streams"
Dan Nelson et al. - "Experimental whole-stream warming increases algal standing crop but reduces consumer biomass"