Day 6: Research Projects, Lighthouse, and Cave Adventures
Today’s post is by Sara Urbanski:
This morning I woke up at 5:45 to get some studying time in before the day started. When I sat up in bed there was a really awesome bright red sunrise. Naturally I took pictures. After breakfast, we met in the lab to go back to Dump Reef to start our research projects. There are 3 different projects but we are all collecting data for each one and collaborating. The projects are (1) counting fish abundance over a 25 meter transect, (2) using three quadrats at random meter marks and observing what species of fish are eating what type of algae in the quadrat over a period of ten minutes, including how many bites that species takes during the ten minutes, (3) scraping algae from the bottom of one square of the quadrat, collecting that algae, and bringing it back to the lab to identify and weigh the biomass. All of these projects will contribute to studying the herbivorous interactions between fish and algae. Particularly, we are looking at if an increase in biodiversity causes an increase in primary productivity of the ecosystem. Weighing the biomass of the algae is how we are measuring primary productivity. When we got to the site, we experienced high wave action with a bit of a current. This made it interesting to try out the research procedures for the first time. The quadrat did not want to stay in place, and a large portion of the scraped algae did not easily go into our zip lock collection bags. While collecting data for the fish abundance project, we saw bluehead wrasse, clown wrasse, longfin and dusky damselfish, ocean surgeonfish, stoplight parrotfish, striped parrotfish, and princess parrotfish. When it got close to lunch time we went back to the research center for pineapple and mushroom pizza.
After lunch Matt and Brian left with Dr. Davis to bring a ladder to a cave that we went to see this afternoon. The girls stayed with Dr. Carlile and Dr. Kelly to identify and weigh the algae we collected from the morning and then met up with the boys at the Lighthouse. The Lighthouse was built in the 1800s and each piece was imported. It is still operational and by walking up steep stairs to the top, we could see a large portion of the island of San Salvador. Next we took a ten minute walk to the Lighthouse Cave which Dr. Davis gave us a tour of because Dr. Kelly and Dr. Carlile did not want anything to do with it (Editor’s note: though we want the best for our students, some of us have very strong opinions about enclosed underground spaces!). They came into the first room which was large, open, and full of algae, stalagmites, and stalagtites. Dr. Davis explained to us that the cave has marine water in it and showed us the obvious high tide mark which was a rusty colored line along the cave walls. We went at low tide so that we could go inside and explore. After hiking through the trails on this very humid day, we were all very hot and slimy from bug spray. The water in the cave was incredibly refreshing and did an excellent job cooling us off. Dr. Davis also told us that when sea level was 6 meters above where it is today, the cave was a place of high churning energy waves. This is different than today because now it simply acts like a lake but with tidal changes. The water was barely moving.
We went through the cave for about an hour, stopping along the way to learn about different aspects of the cave itself and also the study of caves. For example, Dr. Davis told us how scientists used to believe that certain bell shaped formations on the ceiling were formed from bats peeing up and their pee corroding the rock. After videotaping the bats, scientists learned that that is not how bats pee and the explanation of the bells is still unknown. We all gathered together in one of the rooms in the cave and turned off our flashlights to see how completely dark it is. We were told to put our hand in front of our face and look at our hands. If we thought we were seeing our hands, we weren’t. It was what is known as a ghost hand which is simply that our brains think it is seeing our hands even though it is too dark for that. Being able to walk, crawl, swim, and climb in the cave was such a cool experience!!! We had a blast swimming under small gaps in the cave, feeling our way through the rocks, and looking for other tunnels. We were all very thankful that Dr. Davis was kind enough to take us there. We then took a truck ride back to the field station, had very much needed showers, and a delicious dinner. Tonight’s dinner was different because there were some vendors selling souvenirs outside, which were mostly handmade jewelry made out of shells and beach glass from the island. After dinner we met in the lab to go over pictures we took and discuss our projects.