Now that we had settled into our new home for the next week, it was time to begin our research. We had the privilege of going to Belize to conduct an ecological study on a species of sea stars that are commonly found in an area very close to the research station. The species we were looking for is called the cushion sea star.
What kind of ecological study were we doing?
Well, we looked at general population dynamics – size, color, whether they clump together or are territorial, as well as movement patterns.
Now, the bigger question is, “Why are these guys so important?” Cushion Sea Stars live in a very sandy flat area the locals call the “swimming pool.” Here, they feed by creating a mound of sand, pushing their stomachs out through their mouths onto that sand, and then digesting tiny bits of algae and micro-animals. Gross. This, in turn, cleans up the sand and keeps the habitat healthy. They act as the earthworms of the sea, making the sand nutrient rich for many other species of commercially and ecologically important fish and marine species.
To look at the population dynamics, we first had to set up a grid underwater with small orange flags. Because we don’t have gills, we decided to use scuba gear to do this. We loaded our gear into a tiny boat and our driver, Buress, took us out to the swimming pool. When we found a good number of sea stars, we geared up and plopped into the water to begin setting our grid. It took us about 2.5 hours to set the first half of the 100m by 50m grid and about 2 hours to set up the second half. Let me tell you, 2.5 hours underwater is extremely tiring. AND THE HUNGER! Scuba really does make your appetite go crazy! Once the grid was set up, we broke into two teams and swam by each grid square (5mx5m) and took pictures of each star inside of a caliper. This let us look at the color morphs and the size of the stars later on the computer. Using that data, we found the trends in size, color, and based on how many sea stars were in each grid we could determine the way these little guys aggregate. “Aggregate” is a fancy word for how they hang out – whether they are close together or evenly spaced out.
To look at the sea star movement, we simply used a nontoxic dye to stain the sea stars. We took 10 lucky individuals at two sites and stained them in patterns to discern individuals. Then, using the same flags we used for the grid, we went out in snorkel gear and found the individuals and marked a flag next to them. Sometimes we were out looking for these dinner plate sized sea stars for 2 to 3 hours at a time. We had no idea these guys could move so quickly! At the end of the week we measured the distance and angle from flag to flag in order to map it out for the data write up later.
We also took some time to work at Alligator Island, a stone’s throw away from the research station. Here, we looked at the aggregation of three species of sea urchins. We started this study last year. For about 2 hours, we waded in 3 to 6 feet of water looking for sea urchins. During our time at Alligator Island, we noticed a huge change in the habitat. The area was becoming overtaken by seagrass (not good). It was extremely disheartening to see how drastically the ocean can change in one year.
Doing research is hard work. And doing it in a place like Belize, on a beautiful tropical island, does not make it any less exhausting. We would spend anywhere from 6 to 10 hours on a tiny little boat or in the ocean. Many people have been under the impression that we simply got a free vacation, but let me tell you…it was a lot of work.