The Coral Whisperer

In a sanctum that few outsiders glimpse—the laboratory at the New England Aquarium—Liz Burmester pushes through two swinging doors signed The Coral Room (or the Room of Requirement). The parenthetical, a reference to the ever-morphing chamber in the Harry Potter books, attests to the room’s multiple purposes. Mesmerizing blue blubber jellyfish live here, for example, but the room is mainly about coral. Against one wall, 16 fish tanks, stacked on two parallel shelves, hold trays containing 400 Astrangia poculata (northern star corals) for Burmester’s experiments.

Burmester (GRS’16) dons a white lab coat and protective glasses and takes a small specimen of a coral colony to a work counter. Using a scalpel, she scrapes a tiny bit of tissue from the colony, then cleans the wound with a Waterpik. Depending on this coral’s resilience, it should heal over the next 30 to 60 days.

“I feel a little bad about it,” Burmester, a vegetarian, says of the infliction, even though she knows that the coral’s primitive nervous system almost certainly can’t feel pain, and its cousins in the wild endure all sorts of injuries from predators, storms, and humans. Burmester talks like a loving pet owner about these animals that look like rocks. “We feed them shrimp in a slurry,” she says. “It’s pretty cute. We use a turkey baster.”

Corals are nature’s mishmash: animals with stony skeletons and a plant-like hunger for sun-derived energy, obtained from symbiotic photosynthesizing algae living inside the coral. Dubbed the “rain forests of the sea,” coral reefs house up to 25 percent of marine species—including an estimated one-tenth of the fish eaten worldwide—and that’s just the beginning of their beneficence. They shelter coastline communities against storms and hurricanes; they’re a source of proteins that appear to block HIV infection; and they’re tourism magnets, with the United Nations estimating that a square kilometer of reef powers at least $100,000 of business annually.

Yet around the world, coral reefs are dying. Pollution, coastal development, harmful fishing practices, and warming and acidifying waters from fossil fuel emissions have conspired to threaten 75 percent of reefs worldwide, a percentage expected to swell to almost 100 percent by mid-century, says John Finnerty, a College of Arts & Sciences associate professor of biology. He is a faculty mentor to Burmester, who studies A. poculata in hopes of finding better diagnostic tools for sick reefs. Her work is part of a collaboration, called Coral Whisperer, between BU and the Virginia-based environmental group Conservation International.

A. poculata does not congregate in huge reefs, and the largest one Burmester has seen was about the size of a tennis ball. Its value as a research stand-in for larger reef corals comes partly from its biological similarity (it’s a coral, after all) and from its distinctiveness.

Like its reef-building brethren, northern star corals live in warm waters. But they also thrive in the colder depths off New England, where Burmester collects corals during scuba dives in Rhode Island. Therein lies a vital trait for scientific research: northern stars are the tough guys of the coral world, able to survive with only small amounts of algae. That’s because northern stars derive less than half of their energy from algae’s photosynthesis; mostly, they feed on plankton they snare with their tentacles. By contrast, reef-building corals are much more dependent on photosynthesis for food; when they undergo prolonged bleaching (algae-shedding, something brought on by the world’s warming waters), they can sicken or die.

In the lab, Burmester can observe her 400 northern star specimens in a wide range of conditions that other corals could not withstand: with reduced algae levels, in warm water or cold, or with an injury. These observations, she hopes, will yield insight into why this species is so robust. Is its advantage genetic? (Burmester has specimens’ genes sequenced.) Or does it gain hardiness from its symbiotic relationship with its algae?

Answering these questions, by itself, won’t save the coral reefs. But the markers of a robust constitution in a northern star coral could tell scientists what to look for in reef-building corals to determine whether they’re healthy or threatened. It will also inform coral restoration efforts; Finnerty says some past efforts have simply tried to move coral into new waters, with no real knowledge of their survival needs. Preliminary results from Burmester’s ongoing research suggest colder water hinders recovery in wounded coral.

With current knowledge, by the time scientists realize that a reef is in trouble, it’s too late. “We’re more undertakers than we are doctors,” says Finnerty. “By the time you realize something is wrong, it’s very wrong.

“We’re hoping for better diagnostics,” he says. “We could actually go out to the field and figure out, among corals that all look ostensibly roughly the same, who’s doing well, who’s not doing well, and why, and who’s likely to survive the next five years and who’s likely to succumb. You can actually tease apart the coral’s role in resilience versus the algae’s role in resilience, or the algae-coral combination. Basically, we can mess with this coral in a way that we can’t mess with the tropical reef-building corals.”

Burmester, who will continue the research until she receives her doctorate, has been funded by BU’s Warren-McLeod Fellowship for marine biology research. Her other faculty mentors are Les Kaufman, a CAS biology professor, and Randi Rotjan, a lecturer in BU’s Marine Program and a New England Aquarium associate research scientist.