Week 6: Snails, Snails and More Snails

Week 6 of my internship was a busy and productive, but relatively uneventful one. My frontline mentor, Kiley, was out for the week as she had returned home for a visit after the 4th of July weekend. This lack of direct supervision worked out just fine, as I have now been in the lab for a decent amount of time and am comfortable maneuvering around and completing my tasks on my own. I really just had one big task for the week- processing (seemingly endless) sediment cores that we had taken from our sample sites in both May and June. You may recall that once the cores of soil are taken from each site, they are frozen in dry ice and brought back to the lab, where they have to be dissected in the CMOP cold room. As a brief recap, I cut each core into 1-cm fractions (usually we aim for 9 fractions total, but some of the cores are smaller than others and we don't always reach this maximum number). I then remove and store a small sample from each sediment fraction, that can later have the DNA extracted from it. This DNA is then run through the qPCR to quantify how much of the amoA gene is present in each fraction. Furthermore, I inspect each and every fraction for the presence and number of snails, keeping track of all this in my rapidly-filling notebook.

I have been working through the May cores for the entirety of my internship, but the demands of molecular work have kept me from finishing them. So this week, with Kiley out, I set to work on completing all of the May samples and also began working on dissecting and examining the June samples. We expected that as we moved into the summer, the snail densities would increase in the fractions, as conditions became more hospitable for reproduction. My preliminary results are in line with this! Whereas with the May samples, it was very difficult to find even a single snail in a fraction, in the June samples I am finding snails everywhere I look. In fact, its actually become more difficult to find negative controls, or cores with no snails! For example, at one of our sites called Young's Bay Mouth (YBM), I found only 5 snails in all 4 fractions. However, at YBM in June, I have already found 10 snails in only 2 fractions- so twice as many snails in half as many fractions! This is very encouraging, because we have not been finding any correlations between snail presence and levels of amoA expression in the sediment. We think this could possibly be because we have been finding so few snails so far- after all, there isn't much difference between a fraction with 1 small snail and a fraction with no snails. Hopefully, now that we are dealing with sediment fractions with considerable higher snail densities (such a 1cm fraction with 5 snails!) we will begin seeing some kind of pattern in our qPCR results.