Eureka! Motorcycle oil!
In a few weeks, the Meyer lab will be involved in the Eureka! Program, a local science outreach program for middle school girls. Eureka! (associated with Girls Inc.) provides young girls with the knowledge, the experience, and the role models to encourage their interest in the sciences and higher education. Even today, mathematics and science programs in high school and beyond see an overwhelming male majority. Euerka! aims to change that by showing female students that science is fun and accessible.
Over the course of five weeks, students in the Eureka! program will spend time at Clark University, Worcester Polytechnic Institute, and Becker College, participating in a variety of classes and activities. For two days, the students will be here in our own lab learning about annelids.
In preparation for the Eureka! students, I’ve been preparing a number of activities, including a simple oil pollution experiment. Pollution, especially oil pollution, is a widespread problem for a number of marine species. Delicate invertebrates, like our own beloved Capitella teleta, are particularly sensitive to this pollution. I’ve designed an experiment that will highlight the dramatic effect even small amounts of oil can have on the development of C. teleta. The girls will be given several separate dishes of C. teleta embryos. They will then treat some dishes with a “high concentration” oil solution, some with a “low concentration” oil solution, and some will be left alone as a control. They will make predictions about the effect of the oil on the embryos, leave them overnight in their various solutions, and then observe them the next morning.
Since very little literature (read: none at all) exists on C. teleta’s tolerance for oil pollution, I did some preliminary experiments to figure out what concentrations we’d use for the actual experiment. With some motorcycle oil Professor Meyer brought from home, I made several different mixes of oil and seawater. Without any idea of what concentrations to use, I arbitrarily picked a few that covered a wide range (from 1 part per million (0.001%) to 1 part to thousand (0.1%)). Ideally, I aimed to find a low concentration that would have little to no effect, and a higher concentration that would cause clear physical deformities without outright killing the embryos.
My initial batch of test dishes went very poorly. Because I apparently can’t do math at 9am, I severely miscalculated the concentration of the oil. All of my batches were 1000-fold the intended concentration (oops!!). Unsurprisingly, the highest concentrations were dead by the end of the day. However, the lower concentrations (those that survived, anyway) displayed noticeable deformities
The next day, I tried another set of batches (this time I double-checked all my math!). I was able to find two perfect concentrations of oil. 1uL of oil per 1mL of water (or 1 part per thousand, 0.1%) has only a slight effect on the embryos after 24 hours. It makes them swim a little more slowly and causes their bodies to become a little lumpy. The “high” concentration is double that, 2uL/1mL, or 2 parts per thousand (0.2%). This concentration causes severe physical deformities and reduced swimming speed. Now knowing these experiment parameters and what to look for in the embryos, I was able to design the protocol sheet (the instructions, so to speak) and the observation worksheet.
Hopefully the students will enjoy the experiment and learn a bit about the extreme harmful effects that oil pollution can have on marine creatures!
Til next week,