SEA Currents: Robert C. Seamans
March 04, 2020
A Foul Undertaking
36°48.2’ S, 179°12.6’ E
Why do we become so excited when we see whale spouts? Or when a pod of dolphins can be seen swimming along the bowsprit? Or when the occasional Mola mola floats on by? As I peer off into the vastness of the open ocean, I see a beautiful desert; dynamic and fluid, yet, on the surface, practically devoid of life. Like a shroud, the rolling waves separate our ship from what lies below. Nonetheless, we have undertaken the great task of uncovering this mystery. Driven solely by mere glimpses, our fascination with the sea fills us with an insatiable desire to discover. In fact, it feels as though the less we are given, the more we yearn to seek. Therefore, we employ the best known method for piecing together nature’s puzzles: science.
I didn’t always appreciate the ocean in this way. Although I study biology, my previous interests were in medicine. The only research experience that I had had come from my summers studying cancer. Science to me meant white walls, lab coats, and, may I add, being on land. Naturally, I felt out of my element when it came to deciding what I wanted to do for my research project. When it was my turn to speak, I blurted out the first thing that came to mind: “why don’t we take a look at what grows on the side of the ship?” I had no idea that something I blurted out and earned a few chuckles from my classmates would turn into a unique project that has given me a whole new perspective on science and how we study the oceans.
Biofouling is the name used to describe the buildup of marine organisms on things exposed to seawater for any significant length of time.
In a few days to weeks, bacteria and other single celled organisms will cling to the surface of these objects, such as docks and buoys, and together, will make up a biofilm that acts as an outer coating. The nutrients obtained from these organisms allow for the growth of larger organisms, such as barnacles and tubeworms.
On a ship, this can have a significant impact to its speed and efficiency. Therefore, special paints called “antifoulants” are used to prevent the growth of marine organisms. Traditionally, the chemical that kills the organism (called a “biocide”) is a metal such as copper. The biocide is designed to release at a rate that prevents buildup. However, the releases of these metals have effects that reach beyond their intended purposes. Bioaccumulation of these harmful metals is well documented, and has the capability of making their way all the way up the food chain, and can even affect humans. A whole field of study is dedicated to developing more ecologically friendly alternatives to traditional antifouling paints.
My research project aims to explore the effectiveness of an antifouling paint advertised as “ecologically friendly” compared to a traditional antifouling paint. The process began with painting glass slides with the paints as well as establishing a control (some without paint) and placing them in an aquarium. A constant flow through of seawater provides the organisms, as well as a dynamic environment and constant replenishment of nutrients. While my initial plan also included placing a fiberglass plate bearing the different paints to the side of the hull, we were unable to fasten them securely (despite chief scientist Jan Witting’s best scuba diving efforts).
Nonetheless, a few weeks in, and I am now at the point where growth is visible on the slides! Under fluorescence at different wavelengths, autotrophs containing chlorophyll glow red and yellow. I am able to count different fields on the slides in order to determine the density of these organisms under each anti-fouling condition, and at different points in time along our journey. Furthermore, using DAPI (a DNA staining chemical), I can see heterotrophic bacteria growing on my control slides and can use their abundance to determine their fouling rate.
SEA has worked with me every step of the way to cultivate my research project and allow for it to happen. Another student, Anna Roethler, also had a project that called for the use of DAPI, which was brought specially on board for our research projects. I am excited to continue collecting my results and building upon my fascination for the ocean.
However, now I am going to think twice about the next time I accidentally swallow seawater!
- Tom Rubino, Carleton College