Off the coast of Labrador, biologists discovered last summer an underwater cliff lined with centuries-old coral. They will return this year to visit this habitat of remarkable richness in order to detail its extent. Narrative.
On July 20, Bárbara Neves, a biologist specializing in cold-water corals, could hardly contain her excitement. In a small compartment on the lower deck of the Canadian icebreaker Amundsenshe devoted all her attention to the monitors transmitting live images of a remote-controlled submarine 600 meters below.
The day before, this same submarine, whose first official scientific deployment was, pointed its cameras at a patch of seabed, off the coast of Labrador, where scientists had good reason to believe they could find corals. never seen in the area.
“There were a lot of sea sponges, very white, very close together. There were plenty of sea anemones. There were starfish clinging to the rock faces. It was starting to get interesting,” says M.me Neves, who works as a researcher for the Department of Fisheries and Oceans Canada (DFO). “And then, we saw one or two corals of the species we were looking for: gorgonians! »
This family of corals, which can produce very large specimens, is considered an indicator of “vulnerable marine ecosystems”. Gorgonians grow very slowly and live for centuries. When they experience hazards, they recover only very slowly. Like all corals, they are also excellent refuges for fish that want to rest or reproduce.
The first finds of July 19 — gorgonians of the species Primnoa resedaeformis — had something to encourage scientists, but without fully meeting their expectations. Off Makkovik, where theAmundsenfishermen had seen, entangled in their nets over the years, the signs of a very abundant population of corals.
David Côté, another DFO biologist, was first tipped off by Wilfred Bartlett, a Labrador fisherman who had built up a collection of dried corals from specimens found in his nets. “Bartlett said, circling a large area on a map: this is around the place where I collected these corals,” reports Mr. Côté.
“When we worked there, it was good to know,” says Mr. Côté. But this area was 250 square kilometers. It’s still very big when you’re trying to find something, especially in deep water. »
“If you don’t know where to look, most of the time you’re going to come across a big pile of mud,” he adds.
More recently, it was Joey Angnatok, another fisherman in the area, who came across some coral. While plunging his equipment into the sea, he realized that an underwater mountain was standing there. By hauling up his nets, the fisherman realized that a whole menagerie of sponges and corals lived there. He wrote down the coordinates so he would never fish there again.
For David Côté, such information is worth gold. The two men, who have known each other since 2006, are in frequent contact to exchange information. Joey Angnatok “spends his entire life at sea,” says Côté. “If anyone can have the slightest idea of a place we should go see, it’s him,” he adds.
In 2020, scientists therefore hoped to put the brand new submarine to good use. Comanche 38, property of Amundsen Science, to see more clearly. This toy equipped with high-definition cameras, mechanical arms, sample boxes and corers replaced the Super Mohawk used from 2003 to 2018 and suffering from numerous technical problems.
The pandemic, however, has forced scientists to take their troubles patiently. Since the use of a remote-controlled submarine requires multiple professionals and technicians, and the places on the ship were limited, the Comanche 38 did not perform its maiden scientific dive.
However, the crew took the time to map the seabed in detail in the region of interest using sonar. We did not find the seamount that Joey Angnatok was talking about, but the precise bathymetry nevertheless made it possible to locate very steep cliffs, favorable to corals.
A rare ecosystem?
The following summer was the hour of truth. The scientists targeted a very steep underwater area, about forty kilometers from the coastal village of Makkovik. After the encouraging signals obtained during the first dive, they fell, on the second day, on an underwater cliff as high as a 60-storey skyscraper.
“We started to see more corals, says Mme Neves. A ! Of them ! Three ! Four ! In the control room, madness set in: everyone was a little too excited. The corals we found were very numerous and close together. When we looked at the screen, we didn’t see much space between them. The biodiversity around was comparable to that of the day before, with the same sponges, the same starfish, the same sea anemones.
In video footage captured that day, the submarine’s robotic arm is busy taking a sample from a clump of coral resembling a large orange mop. Despite this unexpected disturbance, a fish remains sheltered between the branches of its benthic companion.
Corals are part of the animal kingdom, but cannot move. They are polyps, cylindrical animals, cousins of jellyfish, which build a hard skeleton. Gorgonians do not need the sun and feed on plankton. They are usually seen in the rocky seabed, where their skeleton can attach.
The exposed wall — which scientists now refer to as the “Hanging Gardens of Makkovik” — is essentially vertical. This prevents the accumulation of sediments and could explain the presence of gorgonian corals, never seen off the coast of Labrador.
This kind of ecosystem, endowed with a rich marine fauna, impresses amateurs and connoisseurs alike, but is not necessarily rare, maintains Mme Neves. “It is believed that corals are all over the region, and what is missing is the ability to look for them, find them and track them,” she continues.
The submarine opens up new possibilities for exploration, as it is the only equipment allowing the study of vertical walls.
“High importance”
The Hanging Gardens of Makkovik sit just outside a strip of marine territory that Nunatsiavut—the Inuit self-government of Newfoundland and Labrador—wants to economically manage and protect.
According to the underwater maps, Mr. Côté believes that the biodiversity cluster discovered in July 2021 also extends within the territory claimed by Nunatsiavut. “So far we’ve only been able to take a quick look at it, but there will be a lot of science to be done to understand how these systems work and how far they extend,” he says. .
Starting this summer, researchers will again visit the Makkovik site from theAmundsen and immerse their submarine in it. They will also travel elsewhere along the Labrador coast, including a place nicknamed Joey’s Gully, advised by Mr. Angnatok. After two absences due to the pandemic, Inuit from Nunatsiavut will board the ship and take part in the scientific cruise.
In their mission report last year, the scientists wrote that the Makkovik site should be considered a site of “high conservation importance for invertebrates and fish”. However, scientific observations are only a first stop on the long road leading to the establishment of a marine protected area, warns Mr.me Neves.