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.

Wednesday, August 3, 2016

One Fixation Method

Nostoc Pink algal bloom
Sampling days in the field have been long yet extremely productive. We have collected nitrogen fixation data on primary producers found in four streams with varying temperatures. We can calculate the rate that primary producers are fixing nitrogen using a technique called Acetylene Reduction Assay or ARA. This is one method of measuring fixation which allows us to compare how rates of fixation change across a temperature gradient. You may be thinking “Whoa! Back up. What is this girl talking about?” Let me explain. Some primary producers, for example, one of my favorites, Nostoc Pink, can take nitrogen gas (N2), which is abundant in the air, and utilize the nitrogen for growth and other critical cellular processes. But for the organism to use the nitrogen from N2  gas, it must be converted into a usable form of nitrogen. One particular enzyme known as nitrogenase allows for some organisms to be able to do just that! This enzyme breaks the bonds in N2  gas, or as we call it, "fixes N2  gas",  and allows for nitrogen to be transformed into ammonia. Ammonia is a nitrogen-containing compound that can be incorporated into the cell.
Saturating chambers with acetylene gas

ARA, the technique that we have been performing on the streams, mimics the process of breaking the bonds in N2 gas. With this technique, we use acetylene gas in place of N2  gas. Because N2  gas is found in such high concentrations in the environment, it is extremely difficult to detect a change in concentration. Luckily, acetylene is a molecule which has similar properties to that of nitrogen gas. I like to think of them as cousins. Because of their similar properties, the nitrogenase enzyme can break the bond in the acetylene molecule and allows us to detect rates of fixation. When performing Acetylene Reduction Assay, we saturate chambers containing primary producer samples with acetylene gas and take an initial gas sample. We let the algae “do its thing” for 2 hours and then take a final gas sample.
Charlie and Me
Back at the lab, we use an instrument called a gas chromatograph to detect gases and concentrations of gases that are present in the samples we collect. We can determine differences between the initial gas sample and final gas samples to calculate a rate of acetylene fixation. We then can use a known conversion factor which allows us to determine the rate at which  N2 gas is fixed by each primary producer based on how fast they fixed acetylene gas. This data allows us to determine differences in fixation rates across streams and temperatures. It is very exciting to watch the data compile and observe “fixation” right before my eyes! I have spent many hours working with the gas chromatograph; one might even say we have become very close friends. Today I am spending my time in the lab running gas samples with our gas chromatograph which has been named Charlie by some of the other team members. I intend to find out the story behind Charlie's name, and I will be sure to let the story be known!


Friday, July 22, 2016

Happy in Hengill

Liesa (right) and I (left) filling balloons with
acetylene gas to put in the chambers
Hello! I’m Annette, a St. Kate’s undergraduate student working with the Iceland team this summer. I’m a senior majoring in biology and I am especially interested in ecology. I’ve been learning so much from working with this incredible team. Each day brings new surprises and problems to solve, so we are always brainstorming and adjusting our plans. My favorite part is going out to the Hengill Valley to get samples from the streams. I love working outside, especially with all the nice sunny weather we’ve been getting! I am very grateful to be working in such a unique place with steaming hot pots, moss covered volcanic rock and geothermally- heated streams. I enjoy learning about the organisms living in these streams and the role they play in the food web. There are so many interesting aspects to be explored in these streams that it’s hard to pick just one to focus on. So far, I’ve been exploring the relationship between biodiversity and temperature.

Out in the field to measure nitrogen fixation



Everyone on the team has so much knowledge to offer and I’m taking every opportunity to learn from them. I’ve been helping Kate, a PhD student from the Montana team, with estimates of percent cover for each of the primary producers found in the streams we are sampling. This is done by recording what is growing at multiple random locations in each stream and used to determine the area of the stream bed covered by each species.  With this information, we can then calculate the rate of nitrogen fixation and metabolism for the whole stream, based on our measurements for each individual species. Liesa and I spent a lot of time problem solving in preparation for gathering nitrogen fixation measurements. All is going well, as we’ve been gathering those samples for a few weeks now and putting all our planning into action. I feel very lucky to be working with such wonderful people!

Watching the football game in downtown Reykjavik!
In our free time, Liesa and I have been hanging out with the other team members and exploring Reykjavik. On one of our days downtown we joined a crowd of 20,000 people to watch Iceland’s football team win and move on to the quarter-finals in the Eurocup! It was really fun to watch the game on a big screen in the heart of the city and join the crowd in cheering “Áfram Ísland!”

Sunday, July 10, 2016

Not Rotten Here… Anymore!



Jill (left) showing Annette (middle) and Me (right) primary producers!
Time is passing quickly here in Iceland and each day seems to run into the next or skip it entirely! This may partly be attributed to the midnight sun, but also to how busy and productive our days in the lab and the Hengill stream sites have been so far. Each day we are faced with new questions to answer, problems that need solving, and moments of chaos that somehow turn into cooperative learning experiences. Annette and I have been put on the task of building a mechanism to maintain constant circulation of water in chambers that will be used for measuring metabolism rates of algae and other organisms. We have overcome many engineering problems along the way and with creativity we have successfully built a mechanism that completes this task. We have attached magnets to computer fans that will sit on top of the test chambers. When the fans are turned on, the magnets on the fan will spin and in turn, spin a magnetic stir rod inside of the chambers to maintain constant circulation. The tests will begin shortly and we are confident that things will run smoothly!

A day off exploring Viðey island
I almost forgot to introduce myself… My name is Liesa Erickson. I am a senior, biology major at St. Catherine University, and I am more than excited to be in Iceland this summer as part of the 2016 Fixation on Ice research team! After the first couple of days here, I was beginning to miss Minnesota’s delicious tap water. Because geothermal activity heats the water in Iceland and often gives off a sulfuric scent, I was convinced that I would smell like a rotten egg for the next three months.  I decided that taking a shower would not be too much of a problem as the sulfur smell can be easily masked by a sweet smelling shampoo, but the smell of my breath was awful. And it just continued to get worse after brushing my teeth! If only you knew my relief once I discovered running the cold water for a little while allows for the purest, egg free smelling, glacier water to pour right out of the faucet!! No more stink for me. I’m sure the team appreciates it.


Jill and I collecting algal samples
Iceland has been very good to us! This summer has had some of the best weather that the team has had in the past years of being here. We can’t complain! One thing we noticed upon arrival was the lack of trees compared to the large forests back home in Minnesota. As Annette and I were arriving to Reykjavik for the first time, we realized the trees were missing and a few miles of driving had passed before we had our first tree sighting. Even so, the landscape here is beautiful and millions of purple lupines have begun to blossom across the country. Spending time in Iceland and the Hengill Valley has reminded me of how important our work is in preserving and understanding the nature around us. With that said, Jill and I have been working together to collect and identify algae in the streams. She has been teaching me the different primary producer and algal species and how to differentiate them from each other. It amazes me how diverse each stream is from one another, and I am eager to see how they change throughout our time here.

Tuesday, June 21, 2016

Ecological Engineering

Science involves making measurements to estimate process that are sneaky and difficult to measure. To prepare for this, we need an arsenal of equipment specifically designed for the task at hand.

Bond. James Bond.
Annette (right) and Delor (left), ready to glue anything into submission

Liesa (left) and Annette expertly inventing

"Your mission, should you chose to accept it, is to construct a sampling chamber that can be used for incubations in the light, darkened to measure the same processes with no light, along with creating a device to circulate the water in the chamber without interfering with measurements. This message will self-destruct."

The St. Kate’s team has chosen to accept this challenge, in addition to helping with stream sampling as a part of the larger Hengill 2016 crew. Liesa and Annette have been expertly preparing equipment for upcoming analyses, flexing their engineering muscles and showing off their scientific prowess.


An Ecological Stir Plate, in all it's glory
The chambers in question hold our samples, along with a stir bar. This stir bar is propelled by magnets attached to a computer fan – an ecological stir plate. As the magnetic fan spins, so does the stir bar thus stirring the water to mimic conditions found in the stream within the chamber. This stir plate has been carefully water-proofed so it can be completely submerged in the stream – a handy modification for processes that need to be measured in stream ecosystems, and certainly no easy task. Good thing we have handy women to take on the task! It has been great getting to see Liesa and Annette jump into these tasks with fervor, using their backgrounds growing up tinkering and their natural curiosity. Will this adhesive work? What are the limitations? Is it safe for aquatic environments? Not only have they been asking the right questions, they have been tenaciously working to find the answers. As Nobel prize winning chemist Michael Levitt said, “If you know where you’re going, you’re not gonna find anything really interesting”. Innovation and curiosity have brought us to solutions that are both interesting and functional!



We have darkened chambers with an expert mix of duct tape, adhesive, and garbage bags. Ecologists are nothing if not resourceful! Keep an eye out for more updates as we see if the equipment can hold up to the capricious Icelandic conditions as well as these Minnesota women can.

All of our hard work is paying off!

Saturday, June 11, 2016

Summer 2016 Field Season Begins


Annette and Liesa working on our chamber design -
 making some improvements to the engineering.
Yes, the summer field season in Iceland is off to a great start!  We have hit the ground running this year and the weather has been so nice that we have been out in the field getting our first set of measurements underway.  As a result, we have been slow to get blogging.  Our St. Kate's students, Liesa and Annette, have been working closely with our colleagues from Montana State University and the University of Alabama on some of our big team sampling efforts and learning a great deal about the streams they had heard so much about, but hadn't seen first hand yet.  They have also been spending time in the lab working on the design for the chambers which we will use to make many of our measurements this summer.  I will let them write about how their experience compares with their initial expectations and fill you in on their early project development.  

Of course, while the weather has been unbelievable, we have still encountered much rain and some days have been very cold and soggy.  But, we are in high spirits and we have such a great group of people to work with.  So, we are off to a strong start and very excited to see what new knowledge emerges from our work this season.  This year we are studying the interaction between temperature and phosphorus fertilization - and how these two factors can interact to affect how stream ecosystems function.  Understanding how both warming and nutrient addition can affect stream food webs and the way that ecosystems process and cycle nutrients is important in our efforts to predict how freshwaters will respond to both current and future environmental change.  So, stay tuned for updates from our team and more about our results as the summer progresses.  We have a very busy weekend coming up with a full day of water chemistry sampling on Saturday, followed by bug, organic matter, and algal sampling on Sunday.  Then, we are hoping for a bit of a break to catch our breath and maybe write a blog! In the meantime, we have many new photos in the slideshow, which capture some of our nice weather and initial days here together this summer.

Delor, Nate, Liesa, and Annette working on the channel experiment.
Weather isn't too bad....
Okay, maybe the black flies are bad...
With little wind, the black flies can be quite bothersome!
They are good at finding your eyes and ears.