If you’ve read the news recently, you’re probably familiar with a severe marine heat wave ravaging waters off the coast of Florida, making the ocean feel like a hot tub in some parts of the state.
The potentially record-breaking ocean temperatures don’t just make a sweaty day at the beach less refreshing — they also threaten the survival of coral reefs. This matters for everyone, not just divers and snorkelers, scientists say.
So why do we need coral reefs? Coral reefs are ecosystem engineers, according to Liv Williamson, an assistant scientist of marine biology and ecology at the University of Miami.
“They are home to over a quarter of all marine species that we know of, even though they take up less than 1% of the ocean floor,” she said.
Coral’s three-dimensional structure creates a habitat for marine organisms, similar to the role trees serve for the creatures living in a rainforest. Williamson doesn’t want to imagine an ocean without coral reefs. Without the so-called rainforests of the sea, she suspects populations of all kinds of marine species would either die out or dramatically diminish.
Sea life relies on coral reefs, but as inhabitants of what Williamson calls one of the fishing capitals of the world, so do Floridians. Menu items such as snapper, grouper, lobster, shrimp and conch make up the protein intake of many coastal residents — all marine species who depend on coral reefs for their livelihood.
In helping to get fish on our plates, coral reefs support the economy, too. In 2021, Florida seafood production accounted for nearly 3,300 jobs, according to the Florida Department of Agriculture and Consumer Services. In that year alone, 110 million pounds of fresh seafood were harvested, constituting a dockside value of $262 million. Without coral reefs, these numbers could plummet.
But coral reefs’ economic impact goes beyond the commercial fishing industry. The total tourism value of Florida’s Coral Reef — a stretch of coral extending from the Dry Tortugas to the St. Lucie Inlet — is estimated at $1.1 billion annually by the Florida Department of Environmental Protection.
The Florida Keys are the No. 1 diving destination in the world, according to Bill Precht, a coral reef scientist based in Miami. If the kaleidoscope of colors across the seafloor is dulled or disappears entirely, ecotourism in the Keys might suffer, with reverberating effects throughout the state.
Natural sea walls
Coral reefs act like “big mountains underwater,” according to Williamson. These submerged mountains help to break up the energy from waves passing over them. In some places, up to 97% of wave energy can be dissipated by healthy coral reefs — energy that would otherwise be hitting the coastline.
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This is especially relevant in places such as Belize or Australia, land masses surrounded by well-developed reefs, Precht said.
When coral reefs crumble away, they leave an empty, flat bottom on the seafloor, Williamson said. That makes coastal communities much more vulnerable to damage from waves during storms or longer-term erosion.
Coral reefs could even be a natural remedy to rising sea levels, whereas a concrete seawall might fail to keep up given its inability to grow on its own, she said.
What is coral bleaching?
Coral is an animal. Within its body, coral hosts tiny algae through a symbiotic relationship, which is when two different kinds of organisms live together and benefit one another, Williamson said. The coral gives the algae a place to live, and in turn, the algae convert energy from sunlight into food for the coral through photosynthesis.
The algae are what gives coral its brilliant blues, greens, yellows and browns, Precht said.
When temperatures get too high, the coral expels the algae from its body as a defense mechanism — almost like a human throwing up because of a stomach virus, he added. The algae can still photosynthesize, but because the algae are no longer in the coral, the coral no longer benefits. The coral is still living, but it falls into a weakened and starving state without its main energy source.
Bleached coral is also more susceptible to illness, such as the lethal stony coral tissue loss disease, according to the Florida Department of Environmental Protection.
Occasionally, coral stays bleached for some time and then dies off. Other times, when the water gets cooler, the coral will recolor and revert back to normal. But this summer, “corals are dying faster than we’ve ever seen before,” Precht said.
In some cases, the bleaching step is being bypassed — extreme temperatures are killing coral outright.
“It’s not just starving to death, they’re actually cooking in some of these water temperatures,” Precht said.
Here are 10 ways you can help protect coral reefs
Marine heat waves that threaten coral reefs are primarily caused by climate change, experts at National Oceanic and Atmospheric Administration say. Besides reducing the global carbon footprint, here are 10 things you can do as an individual to protect coral reefs:
- Eat sustainable seafood.
- Conserve water whenever possible.
- Don’t touch reefs when diving.
- Use reef-safe sunscreen.
- Volunteer in local beach or reef clean-ups.
- Don’t give coral as presents: leave them on the reef.
- Use energy-efficient light bulbs to reduce greenhouse gas emissions.
- Anchor boats away from reefs.
- Refrain from using excess fertilizer, or stop using fertilizer altogether. Fertilizers can increase unnecessary algae growth and block sunlight for corals.
- Don’t throw trash in the ocean. And if you see trash on the beach or in the water, pick it up if you can.
“Lastly, the most important tool we have in our toolbox are the people that are going out day after day, working tirelessly on the coral reef problem,” Precht said. “There are many great young brilliant scientists, working in the field and in the laboratory to try to make a difference.”