Closing the streams

After about a month of running our experimental streams, it was time to finish out the experiment. The main thing we wanted to measure was how much biofilm and of what different types grew in the streams under different treatments. Biofilms are groups of microorganisms which grow on a surface. We usually think of biofilms as being comprised of algae, but they can also have a lot of bacteria in them as well.

I have to admit, I was a little worried nothing would grow, which would make it difficult to measure any effects of the treatments. Fortunately, that was an unnecessary fear! After 4 weeks of running, it was incredible how much biofilm our streams had grown! You could clearly see it on both the tiles and gravel we had placed in all the streams.

Biofilm growth in tiles in the streams 

Biofilm growth on rocks in the streams

 A lot of the biofilms were green and looked like algae, like this rock below, but we took measurements that will help us determine the quantity and composition of the biofilms in each stream.

A rock covered with algae

 We will have to analyze all our samples and run statistical tests on the data before we will know if the experiment "worked" scientifically speaking-- that is, did the treatments have significantly different effects on biofilm development that we could measure? However, after running smoothly for one month and growing lots of great biofilms, I can happily say the experiment was a success! When we started this process, we didn't even know if we could get these things to hold water, much less act like small streams. Truly, we owe all the success of this experiment to Paul Geemi, our tireless field assistant.

Geemi changing water in the streams

Geemi camped next to the streams for one and half months, just to help maintain them and keep them running. He changed out 50% of the water in each stream every day-- that's a lot of pumping water and filling and carrying buckets! He monitored the power that kept the paddlewheels turning and switched things over to battery when there were power outages, even in the middle of the night. He also did a great job doing outreach and education for the many people who came by and wanted to learn about the experiment. And through it all, he kept the most thorough and well-written field notes I have ever seen!

Geemi doing outreach about the streams

Field biology is full of unsung heroes-- the people actually out there in the heat and the rain and the dark, doing the work, carrying the heavy weight, monitoring the results, keeping things working. Often times, these are not the same people who end up analyzing and writing up the data, so they don't always get a lot of credit for the work they do. Geemi is definitely the reason these streams worked as well as they did (or even at all!), and we are super grateful to be able to work with him. Thanks Geemi!

Geemi, the unsung hero of the experimental streams