The Sanibel-Captiva Conservation Foundation Marine Lab is hosting two eighth grade science projects at The Sanibel School this semester.
The school asked its eighth graders to come up with projects that were relevant and could be completed by December 1st. SCCF reported that two students have chosen to look at the effects of climate change on water quality and ecosystem changes.
Euan Bonhaiag chose to look into seagrasses based on information he heard all too often at home from his father, SCCF Research Associate Mark Thompson. Ewan is an avid surfer, and he combines his father’s conversation with the observation that the water around Sanibel gets hotter every summer to the point that he sometimes has to get out of the water to cool off.
Could the water really be getting hotter and could the hot water fry the sea grass? He sat down with his father and they came up with a plan to solve the proposed problem with an experiment.
“I analyzed water temperature data taken over the past 15 years in shallow areas where seagrass has disappeared,” Thompson said. “There is an almost linear increase in average hourly water temperature in areas where seagrass has been lost.”
Meanwhile, Grayson Goesling was concerned that algal blooms were becoming more prevalent around Sanibel and people were saying the blooms could be harmful. SCCF school representative Richard Finkel directed him to the marine lab to develop an experiment that could look at the impact of climate change on the increase in algal blooms.
While Yuan wondered if seagrass was being damaged by increased water temperatures, Grayson found in the scientific literature that rising water temperatures caused by climate change could also affect algal growth. He developed a hypothesis that increasing water temperatures could increase algal blooms.
After discussion with their host mentor, the students agreed to have three tanks: one control, one treated with a water temperature of 91°F, and one with a water temperature of 98°C. The control will simulate the temperatures seagrass experiences in the typical October to November season in Florida.
Thompson’s data show that seagrass now typically experiences more than a week of temperatures continuously above 91°F in shallow water bodies (treatment 1). The data also show that temperatures often exceed 98°C for shorter periods (Treatment 2).
Both students stopped to look at one of the most noticeable effects of climate change on the environment – rising temperatures. Ewan would ask if rising temperatures caused the seagrass to disappear, while Grayson would ask if rising temperatures would lead to more widespread algal blooms. Since both hypotheses involved a constant-temperature bath, they created one that both could use. Ewan’s seaweed grows in the same bathroom as Grayson’s seaweed containers.
Grayson and Yuan will analyze water quality data using YSI water quality sensors. The sensors are able to measure the concentration of the pigments chlorophyll a and phycoerythrin in the water, which is a good measure of how much algae is in the water, while an increase in both means more algae. Yuan will also count the seagrass shoots before and after the experiment and weigh the seagrass biomass in each treatment and compare the differences.
“The design and execution of this experiment will give students a full dose of the thrill of science,” Thompson said. “Asking questions, posing problems, designing tests to answer the questions they ask, and then asking more questions. Through application, science can become a wonderful process for discovery.”