Urban coral that have thrived near bustling Port Miami — despite ship traffic churning up pollution and bay bottom — are more resilient than their cousins along Florida’s reef, a new study from the National Oceanic and Atmospheric Administration has found.
Scientists say the findings, which established a baseline for conditions, could help them heal ailing reefs battling impacts from climate change.
“These are conditions that in other areas would kill or stress out corals. So the question is, how are they able to persist? What are they doing that allows them to be able to keep up with these conditions?” said Ian Enochs, who leads the coral program at NOAA’s Atlantic Oceanographic & Meteorological Laboratory. “So it's a little bit of a ray of hope.”
Just since the 1970s, reefs around Florida and in the Caribbean have lost more than 80 percent of their coral from disease and warming oceans. In the Keys, coral covers less than one percent of the reef. Off mainland South Florida, it’s about six percent. That loss comes with a huge cost. Between Fort Lauderdale and Miami, scientists have estimated a healthy reef can provide about $1.6 billion in protection from severe hurricanes. Restoring disappearing species like staghorn, which once blanketed the reefs, can also vastly increase the power of the reef to shred storms.
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Enochs, the study’s lead author, launched the investigation to measure and document conditions after Coral Morphologic founder Colin Foord invited him on a dive in the busy channel several years ago. Foord’s underwater cameras, that feed a steady stream of images of sea life to his popular Twitter feed, @CoralCityCamera, helped supply images for the study.
“I had heard that there could be some corals here and there. If you're walking by a sea wall, you see something that looks like a coral,” Enochs said. “But when we jumped in the water, I was absolutely shocked.
Coral were sprouting from piles of trash and clinging to rocks tumbled on the bottom of the channel.
“Imagine a beautiful coral reef and then imagine the opposite of that,” he said. “There is trash and signs of humanity everywhere. But even on all those rocks, even on trash, there are corals growing. “
There were also a surprising variety of species, many of which have become harder to find on the offshore reef battered by warming waters and disease.
So for the next three years, researchers collected data on temperature, water flow, salinity, acidity and other factors that might affect the coral. Using Coral Morphologic’s cameras, they kept tabs on the fish and other marine life that visited the coral.
“Then we sat down and we got to counting and measuring what was going on. A nd what was going on is pretty amazing. Despite very nasty environmental conditions, corals and diverse communities,” Enochs said.
The next step is figuring out why. Researchers have some theories: the symbiotic algae that live in the coral may be more resilient or the coral themselves may be overfeeding and getting tougher. The angle of corals growing on seawalls might also help them avoid sediment pilling up and stressing them out.
Coral sprouting from unexpectedly harsh or isolated locations isn’t unheard of. Last year, researchers discovered a pristine reef more than 100 feet deep off Tahiti. It’s possible Miami’s urban coral retain some genetic quality that allows them to persist among the port’s busy traffic.
“Refuge is probably not the right word, but maybe there's a repository for some genetic material that we could use for restoration,” he said.
If they can figure out what it is — either the secret sauce in the coral or the conditions that come together to make them more resilient — Enochs said scientists might be able to capitalize on it and apply it to coral growing on reefs. That’s where they provide the most benefit, providing both habitat for fish and strong barriers for storm surge expected to grow worse along the Florida coast as climate change drives up sea levels and pumps up hurricanes.
“There are a whole bunch of mechanisms that could be at play here. It could be none of them, it could be all of them,” he said. “What's really exciting about this study is we're really, for the first time, quantifying the amount of stress these little corals are dealing with.”
