Lightening the Load

Rock covered in algae - all of which will be scraped off.
Then, the rock can be traced.

Even though we’re not in Iceland, we are hard at work here in Minnesota. For the last few weeks, I have been working on entering data into Microsoft Excel, and Aimee and I have been working with samples and data from the trip. As astute ecologists, we often wonder if we are measuring the most accurate number and getting accurate values for nitrogen fixation rates. Once we know how to make the measurements for nitrogen fixation, it becomes easy to slip into the habit of trusting the values we get from our data. However, being the perfectionists we are, we have learned otherwise. Our work is simply not done once we return from the field site, nor is it done after several days of lab work. Measuring nitrogen fixation, or any biological process, involves consistency in the field work and the lab work, and ensuring that we have all of the information we need to draw the right conclusions from our data.

Recently I have taken on the task of calculating the surface area of rocks that we pulled from the stream in January. When we were in Iceland, we took rocks from the stream, measured nitrogen fixation rates, and then scraped the algae off into a container and took the algae back to the lab. Later on, we would need to know the surface area that the algae inhabited on the rocks, but we didn’t want to carry around the rocks until we needed that information. To make our load a little lighter, we traced the rocks on waterproof paper and then labeled each side of the rock to help us know which sides were covered with the algae. This is like many of the first steps we take when dealing with field samples- transport. How do we get algae, rocks and water samples back home to our lab? Tasks like tracing rocks may seem arbitrary at the time, but it really simplifies our job down the road.

A photocopy of  a rock tracing - with all sides - that was
 traced in the field on January 15th, 2014.

Once we returned home, we were able to scan the rock tracings and load them onto our computers so we have a digital copy of the rock surface areas. However, these images don’t tell us the surface area of the rock on their own and it requires a little work on our part, more specifically on my part, to get the data. Over the last few weeks, I have been using a special computer program called Image J to find the area of the rock that we traced.  Precision is key here.   It is important that I carefully trace the images so that we obtain an accurate area of the rock. This also goes for any type of lab work that we do because without precision, we can't be sure if our calculated results are accurate or due to our own error in the methods.

Image J program - it is simply a tool bar on my desktop
and I open the rock files as photo images and trace them
with tools from this tool bar.

Even though the field work provides much better scenery, the lab work can be just as fun and exciting. Part of the experience of taking all these samples in Iceland is getting to see the final results come together. Sometimes the lab work can seem daunting and overwhelming even, but the end result is really worth it. It's been a fun process for me to see the follow through of a research project and how much work and dedication it can require. It has certainly given me a new perspective on ecological research. The next step in the process it to see the final work put together into a paper or presentation, where I will really get to see everything come together.