Alexa adjusts her snorkel, mask, and fins as she prepares to plunge into clear, blue water. She and four other U.S. high school students are two miles from Isla Ballena, an island off the Pacific coast of Costa Rica. The waters surrounding the island—part of Costa Rica’s Marino Ballena National Park—contain coral reefs that attract visitors from around the world. The students are attending Ocean Camp, a university-sponsored two-week research program that exposes students to oceanography and marine biology. Here, Alexa and her classmates will learn firsthand about marine life, as well as check the health of the reefs and 18 species of coral.
Along with their instructors and a snorkeling guide, the students swim past swaying tentacle-like coral polyps and colorful fish. All the while, they watch closely for corals that have faded color or that seem to be weakened or crumbling. Alexa and her classmates have learned that these are signs of unhealthy corals, which are being threatened by warming and increasingly acidic oceans due to rapid changes in the Earth’s climate. Although corals typically thrive in warm water, it places too much stress on them if the ocean gets too warm. This causes them to lose their beautiful colors and turn white, as if bleached. And a more acidic ocean can make it harder for corals to get the materials they need to grow and that causes them to weaken and crumble.
This is concerning because although coral reefs make up less than 1% of the Earth’s surface, they play a crucial role in the ocean ecosystem—corals provide shelter for perhaps a quarter of the ocean’s species. This is why researchers study changing ocean waters and ask the important question: How will a warmer and more acidic ocean affect corals and what does that mean for the health of our oceans?