Another cold week has passed, and my project has made numerous leaps and bounds since last week. The weekend was uneventful, no field trips to embark on! I took the weekend to relax and read a bit more literature on cyprids. During the week, I cemented my project plans and methods of action. Additionally, this week was all about learning how to present ideas properly as a scientist.
On Monday, I spent most of my day writing and improving my proposal. Richard and I discussed how I should continue with my project idea of studying buoyancy in cyprids, but frame it around answering a question, or a proposed explanation, that was raised in a study conducted by Richard Grosberg in 1982. There, he found that cyprids of Balanus glandula were found higher up in the water column compared to those of Balanus crenatus. He suggested that these differences in distribution might be caused by greater buoyancy in B. glandula or higher sinking rates in B. crenatus. He also suggested that B. glandula simply may be more active swimmers than B. crenatus, which could explain their placement in the water column.
My project address these points – buoyancy and swimming activity. Using a tank with very stable seawater (temperature-regulated water column set to around 54 degrees F), I will time how fast they sink. I will also time active cyprids to see how fast they swim. Then I will also observe cyprids and quantify how active they are. My project requires a lot of patience and focus, but with a steady hand, and a whole lot of coffee, I think I can do it! The rest of the day on Monday was spent setting up my special tank, so that the sinking cyprids won’t get any extra help or hindrance from convection currents.
My cyprid sink and swim tank! The outer tank, covered with insulating Styrofoam, keeps the internal cylindrical tank at a temperature of 54 degrees F. This is so that convection currents do not form in the cylindrical tank. The light at the top of the tank encourages active cyprids to swim and allows me to see my specimens.
On Tuesday, I collected fresh specimens of my two cyprid species with a plankton tow. I got a bunch of B. glandula, but B. crenatus was much less common. I practiced my proposed methods. I dropped a few individuals of B. glandula into my tank and watched them sink down, using my phone’s stopwatch app to measure the time it takes for them to sink two centimeters. I took two successive measurements of them sinking down two centimeters. It was hard to get them to sink in a way that wasn’t aided by the push of my pipette, but after some practice, I could gently drip them into my chamber and measure their descent.
On Wednesday, I discovered some issues in my project. These mostly involved the swimming tests. My original project idea was to perform sink and swim tests on the same individual, so that I can compare the two categories. However, I am no Doctor Doolittle. I could not make individuals of B. glandula perform both behaviors. Some individuals will only sink, some individuals will only swim. If I had more time and patience, I could wait for that special individual that would sink and swim in a reasonable time span, but my time here is limited. I had to do the two tests on different individuals.
With that issue resolved, I turned my focus to sinking my B. glandula cyprids for the rest of the week. I tried setting up a camera with an excellent zoom lens to help monitor the action, but unfortunately the fog building up on the outer tank was too much. By the end of the day Wednesday, I was able to sink and photograph five members of B. glandula for analysis. By the end of the week, I should have 10 members sunk, and have enough data to start running some analysis on buoyancy, or in this case, specific gravity, on B. glandula.