EDITOR’S NOTE: Call to Earth is a CNN editorial series committed to reporting on the environmental challenges facing our planet, together with the solutions. Rolex’s Perpetual Planet Initiative has partnered with CNN to drive awareness and education around key sustainability issues and to inspire positive action.
Sardinia, Italy
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One thousand meters (3,281 feet) under the Mediterranean Sea, a crab tangled in plastic is fighting to crawl across the rocky sea bottom. At 240 meters (787 feet) down, an entire population of bamboo coral is being choked by fishing gear.
These are some of the sights Italian marine biologist Ginevra Boldrocchi witnessed during a deep-sea exploration to the subaquatic world known as Caprera Canyon.
Found in the rough, blue waters spanning some 20 to 40 kilometers (12 to 25 miles) off the coast of Sardinia, Italy, Caprera Canyon is a vast underwater valley that supports a variety of marine life and helps keep our oceans in balance.
It is one of the Mediterranean Sea’s last great frontiers, and one of its largest and most biodiverse underwater ecosystems — but it’s under threat from commercial fishing, high maritime traffic and pollution.
In June, CNN joined One Ocean Foundation, an international nonprofit, on its first mission to deploy a remotely operated vehicle (ROV) more than 1,000 meters (3,281 feet) below the surface to explore the dense sea forest at the bottom of Caprera Canyon, as part of the Rolex Perpetual Planet Initiative.
As scientific project coordinator for One Ocean Foundation and researcher at the University of Insubria, Boldrocchi led this mission to observe an environment no human had seen before — a crucial step in advancing the foundation’s study of the canyon’s ecological importance.
Caprera Canyon is classified as a submarine canyon, which cycles nutrients, stores carbon and provides a habitat for countless marine species, from corals and turtles to sharks and dolphins.
“At the moment, the canyon has no kind of protection at all, so we are going to lose refuge for so many endangered species and we will lose a lot of biodiversity,” Boldrocchi told CNN.
After conducting research at the surface level for years, One Ocean Foundation realized it was time to look deeper, to uncover what lies hidden on the seafloor of the canyon.
Since humans cannot physically dive to the deepest parts of the canyon, Boldrocchi enlisted the help of sailor-turned-engineer Guido Gay, who built a specialized underwater ROV capable of exploring its extreme depths.
“The role of the technology in conservation is very important, because we need to see, to connect, to understand the environment in all details in order to protect it,” said Gay.
Piloted by Gay, the battery-powered ROV surveyed a range of depths from around 130 to 1,050 meters (427 to 3,445 feet) — exploring rocky habitats, taking samples, and observing deep-sea organisms.
Scientists have a limited understanding of the life forms dwelling in the canyon’s deep waters, according to Francesco Enrichetti, a researcher at the University of Genoa working with One Ocean Foundation on this expedition.
“This environment [is] completely unknown, and so we hope to find a rich marine animal forest,” he told CNN ahead of the mission.
Since 2019, Boldrocchi has been collecting data to strengthen the case for designating the canyon a Marine Protected Area (MPA) — a measure that could safeguard it from overfishing, pollution and other human impacts.
“The canyon is really a crossway between France [and] Italy, so you have all these traffic disturbances generating acoustic pollution, plus you have the problem with fishing activities like bottom trawling,” Boldrocchi said. “A lot of these animals which are already considered endangered, end up in the nets and die.”
Much of Boldrocchi’s scientific research takes place near the canyon’s surface, where she collects samples at different depths to assess pollution levels and animal presence.
“We do Environmental DNA (eDNA) sampling to get all the biological traces which are present in our sea water to see all the animals which have passed by in the area [recently],” Boldrocchi said.
Guardians of the deep sea: protecting Caprera Canyon
Guardians of the deep sea: protecting Caprera Canyon
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To capture marine animal sounds and noise pollution, Boldrocchi and her team deploy hydrophones roughly 20 meters (66 feet) below the surface and record audio for about 40 minutes on each expedition.
They also gather zooplankton samples, which are key bioindicators of pollution. Zooplankton are tiny animals that drift near the ocean’s surface, where they feed on microscopic plants and serve as food for larger marine life. As the foundation of the marine food web, these tiny organisms absorb contaminants circulating throughout the canyon’s waters.
“We look for mercury, cadmium, arsenic, iron, zinc; we look also at different kinds of contaminants, like DDT,” Boldrocchi said.
DDT, now prohibited, was once a widely used pesticide.
“Even if [DDT chemicals] have been banned since the 1970s, we still find [it] everywhere, and they interfere with the hormones, with the growth, with reproduction [of marine life],” she said.
After the expedition was complete, the samples and video collected by the ROV were analyzed on land. Their exploration revealed colonies of rare sponges, corals and numerous fish species. It also showed the scars of human activity — discarded fishing gear and litter, causing coral mortality.
“We observed a rare population of the soft bottom gorgonians, completely destroyed by the impact of these long [fishing] lines,” said Enrichetti. Gorgonians are soft corals, often called sea fans, that form tree-like structures and provide a home for marine animals.
Despite signs of negative human impact found at the canyon, there have been encouraging discoveries. One Ocean Foundation’s research has identified the presence of the endangered Mediterranean monk seal — evidence that Caprera Canyon could serve as an important feeding ground for the species.
“We find it basically every time we have sampled, not only each month, but in multiple areas,” Boldrocchi said. “And this is very good news because it means that the monk seal little by little is repopulating and is coming back in Sardinia.”
In 2024, the canyon was recognized as a Mission Blue Hope Spot — a site considered vital to the planet’s health. Building on that momentum, Boldrocchi and the One Ocean Foundation plan to simultaneously pursue multiple layers of protection for the area in the coming years.
“Once we get all the data we need, we are going to move in three different directions — we are going to chase the Important Marine Mammal Area (IMMA) recognition, the second is the Fisheries Restricted Area (FRA), and in the meantime we start working in the direction to get an MPA,” Boldrocchi said.
She said they plan to use the ROV data to support their proposal for the FRA in 2026, when they’ll formally present their findings to Italian and EU authorities.
“We want to show that we have an important community also in the bottom that deserves to be protected,” Boldrocchi said.