Over the course of November, as the first term at UBC began to come to an end, our BIOL 326 class was tasked with coming up with our own experiments. Almost a month later, these are the three lessons I learned by running an experiment on my own for the first time.
- Be prepared to change your plans… a lot!
It took me three tries before I came up with an experiment I liked that was actually possible to run. First, I had planned to test differences between invasive and non-invasive clams. Everything looked like it was coming together, until I found out at the last minute that there was a clam shortage in the Lower Mainland. Seriously. Forced to scrap that plan, I came up with another idea that ended up falling through as well.
In the end, I decided to test the effect of salinity on the common periwinkle, Littorina littorea. Specifically, I was looking at how salinity affected the snails’ ability to handle heat.
- Things don’t always behave the way you want them to.
After leaving the snails stewing in their bottles for three days, the first thing I wanted to test was if salinity had any effect on their general activity level. To do this, I flipped them on their back to see how long it would take for them to flip back. Then I timed how long it took for them to climb out of the water.
I probably should have seen this coming. Snails being snails, took up to THREE HOURS to get through what I described above. Three hours was the maximum time I allotted for the trails, and some of the snails were perfectly happy to use all of it.
- You never quite get the results you expect.
What did I end up with? Waiting paid off – I found that snails from lower salinities were significantly slower both in righting themselves and in crawling out of the tank. So clearly the stress from being in low salinity water is taking its toll on the poor little guys. My strangest result came from my heat tolerance trials however. I found that salinity stress does decrease the snails’ thermal tolerance… but only at moderate salinities. Snails at the lowest salinity showed no difference from snails at the control salinity.
So what’s going on? Well I think it may have something to do with the different ways that snails handle low salinities. When salinities are really low, they simply withdrawal into their shell and only come out when absolutely necessary. So they’re not really under the same stress as snails that are out and exposed to the water. That might account for the differences.
Like most things in science, my experiment generated more questions than it answered. But overall, it did show evidence that there is a link between salinity and heat stress in organisms. Regardless of the results, for me it was a great experience for what it is like to actually run your own biological experiment.
Interested in my experiment? Check out Rebecca Gooding’s excellent thesis on the topic here: