The deep sea is Earth’s largest and least explored ecosystem – a mysterious world of towering underwater mountains, vast plains, and life forms found nowhere else on the planet. It’s a world few will ever see, but it holds ancient knowledge, remarkable biodiversity and plays a critical role in the health of our ocean, our climate, and our future.
Right now, this fragile, extraordinary world is under threat. A range of human activities and climate change are putting species and ecosystems at risk before we fully understand, or even discover, them.
At the Deep Sea Conservation Coalition, we believe that protecting the deep sea starts with understanding it. The Knowledge Hub is your gateway to discovering the wonders of the deep, and learning how this hidden world is connected to all of us.
Here we bring together the latest deep-sea science, traditional knowledge, and expert insights that shape our work to safeguard these incredible habitats and species. Through blogs, interviews, fact files, and stories from those working in and with the deep, we shine a light on why the deep sea matters and why it needs our protection.
Approximately 98% of ocean species live in, on, or just above the seafloor.
Creatures living near deep-sea hydrothermal vents are unlike any other form of life. They don’t rely on the sun for their energy but on chemicals being pumped from below the Earth’s crust, and they convert these chemicals to energy via a process known as chemosynthesis.
Deep-sea life has evolved to live within a hostile environment of extreme pressure, no sunlight, low food availability, and freezing temperatures – or in the case of hydrothermal vents, very high temperatures. These conditions mean many deep-sea species take a long time to reach sexual maturity, grow very slowly, and may live for hundreds of years, making them extremely vulnerable to even just a small change in their environment or to damage caused by human activities – the impacts of which may be irreversible.
The mineral-rich fluid emitted from hydrothermal vents can be at temperatures as high as 400 °C (750 °F). Nevertheless, the species which inhabit these unique ecosystems – such as crabs, clams and tube worms – are adapted to survive and thrive in this extreme environment.
What happens on the deep seabed affects the ocean surface. Deep-sea life supports a complex ocean food web. Many twilight-zone inhabitants migrate to the surface every night to feed, as part of the largest migration on Earth.
Over half of all known coral species live in deep, cold waters. Cold-water corals can live for thousands of years and grow into beautiful structures that can rise 35 meters high.
Some deep-water fish species like the orange roughy can live for up to 150 years, while a deep-sea black coral found in Hawai’ian waters in 2004 was estimated to be 4,265 years old.
In 2023 more than 19,000 new seamounts were discovered in the ocean!
Certain coral species produce compounds used in antibiotics and painkillers, while compounds found in certain deep-sea sponges are potent immunosuppressive and anti-cancer agents.
Studies have also found that compounds found in the deep sea could be key to fighting pandemics; for instance, one of the tests used to diagnose coronavirus was developed from a microbe found in hydrothermal vents.
Seafans contain substances used to treat asthma and heart disease.
The female Casper octopus, only discovered in 2016, wraps her body around her eggs on the deep seabed, often onto a manganese nodule – a lump of rock containing precious metals. She will protect her eggs until they hatch, which can take several years, and often starves to death in the process.
The recently discovered scaly-foot snail, which lives alongside deep-sea hydrothermal vents, is literally iron-plated – the only known creature that has iron sulphide in its skeleton and shell.
Endemism is high in the deep sea, with many species found only in a specific habitat and region.
The mesopelagic zone, between 200 meters and 1,000 meters below the ocean’s surface, is estimated to be home to 95% of the world’s fish biomass.
Cuvier’s beaked whale (Ziphius cavirostris) is the world’s deepest diving whale: it has been recorded at an incredible depth of 2,992 meters.
The deep sea is home to the “impossible fish”, or snailfish, which broke the record for living at a depth of 8,336 meters.
The deep-dwelling anglerfish has a very strange mating ritual in which the male, who is much smaller than the female, bites onto the female’s body, where he remains for the rest of his life, serving only as a sperm bank for when the female is ready to spawn.
For the first time in its history, Trinidad and Tobago's deep sea and adjacent high seas areas were explored by a team led by Caribbeanscientists. Two young scientists onboard, share what a month at sea actually looked like from their side of the boat.
Before the ROV SuBastian of the Schmidt Ocean Institute's research vessel ever touched the deep waters of Trinidad and Tobago, Shauna Edghill was in classrooms and TV studios telling her country that most of its territory is underwater and almost entirely unexplored. This is what came next: ship-to-shore livestreams, late nights collecting and preserving deep-sea specimens, and a team that became family.
Kyle Foster spent a month at sea aboard Schmidt Ocean Institute's research vessel Falkor (too), exploring the deep waters of Trinidad and Tobago, split between two extremes of deep-sea technology, a multi-million-dollar ROV and a hand-deployable camera built for a fraction of the cost, and helped push the low-cost option to its deepest run yet: 2,240 metres.