The deep sea is home to many weird and wonderful creatures, with many species yet to be discovered. But they're under threat from plans for deep sea mining.
Thousands of metres below the ocean’s surface, incredible deep sea creatures live in the cold darkness.
Creatures like the ghost fish, dumbo octopus and deep sea urchin are examples of animals that have adapted to their unique deep-ocean environment.
But their habitat and that of many other marine creatures could be under threat if deep sea mining gets the go-ahead later this year.
A juvenile pancake batfish found between 200m depth and the surface, Gulf of Mexico, July 2018. The adults live on the bottom of the ocean and have been found at depths below 800m. The adults have a body that is flattened out like a pancake and they have modified fins for walking along the bottom. Science Photo Library / Dante Fenolio
The deep sea is broadly defined as the depth where there is less light, at about 200 metres below the surface and below – extending thousands of meters below the surface. Freezing temperatures and high pressure make it an especially difficult environment to explore.
Many of the lifeforms of the ocean floor are yet to be discovered and have been as yet undisturbed by human activity. Over 80% of the oceans remain unexplored.
Deep sea urchin from the Saint Peter and Saint Paul Archipelago in the Atlantic Ocean on the equator off the north east coast of Brazil. These sea urchins are characterised by their surprisingly bright colour pattern, usually red and white. Even more surprisingly, their tests (skeletons) are brightly coloured, too, even after drying, or sometimes fossilisation. Sea urchins move slowly, propelling themselves with their spines © Solvin Zankl / Greenpeace
Scientists from the US’s National Oceanic and Atmospheric Administration (NOAA) have discovered these creatures living near the ocean floor, in the Clarion-Clipperton Zone (CCZ) in the Pacific Ocean.
They are threatened by proposals for deep sea mining. Huge machines would dredge up the seafloor to collect potato-sized polymetallic nodules containing manganese, cobalt, nickel and copper.
A sea cucumber on the seabed in the eastern CCZ. And a new species, a Relicanthus, collected at 4,100 metres deep in the CCZ, that lives on sponge stalks attached to polymetallic nodules. © NOAA / Images courtesy of Craig Smith and Diva Amon, ABYSSLINE Project.
To survive the harsh environment with little sunlight or food, in the constant cold and under extreme pressure, deep sea creatures have developed some remarkable adaptations. Many are transparent like the ones pictured above, to remain hidden from predators.
Deep sea fish are characterised by big sharp teeth, expandable bodies and large mouths, whilst some creatures produce their own light.
Dumbo octopuses live in the deep ocean, up to 4000 metres down. Their dots are clear windows in the skin that gather additional light.
Their ear-like fins – used for moving slowly around – are reminiscent of Disney’s flying elephant, hence the name.
This Dumbo octopus was captured during the 2019 Southeastern US Deep-sea NOAA expedition. NOAA Office of Ocean Exploration and Research, 2019 Southeastern U.S. Deep-sea Exploration.
Young Sergestes crayfish have finely branched antennae that allow them to float freely in the water. Adult Sergestes crayfish are able to prevent casting shadows in the twilight by using weak bioluminescence (self-produced light) on the underside of their bodies, camouflaging themselves from predators lurking below. The intensity of their glow is adapted to the amount of light coming from above.
A deep sea marine larva (Sergestes larva) of a decapod crustacean that can be found in the Atlantic Ocean. © Solvin Zankl / Greenpeace
Swimming sea cucumbers – also known as “headless chicken monsters” – have a special “flap” which they use to “lift” themselves off the seafloor, up to 1000 metres through the water column
They lack lungs or gas-filled spaces, making them more well-adapted to the intense pressures of the deep ocean. The transparent body reveals the sediment-filled intestine looping around from the mouth (top) to the anus (bottom).
This swimming sea cucumber was pictured in 2018 in deepwater areas surrounding Puerto Rico and the US Virgin Islands. NOAA Office of Ocean Exploration and Research
In 2018, scientists found a translucent egg case with a catshark embryo actively swimming inside. Catsharks lay their eggs in a leathery egg case made of keratin – the protein found in hair and nails – onto the seabed.
Inside the egg case the embryo feeds on the egg yolk. It can take 5–11 months for it to hatch.
This catshark egg case was captured in 2018 in a deepwater area surrounding Puerto Rico and the US Virgin Islands. NOAA Office of Ocean Exploration and Research
Bobtails, sometimes referred to as “dumpling squid”, usually live in shallow coastal waters. They are about as big as your thumb and have a special light organ in their body allowing them to generate a glow, cancelling out their shadow and thereby camouflaging them. This bobtail is a benthic species, which means it lives at the bottom of the ocean.
This Bobtail was imaged by a remotely operated vehicle during the “Windows to the Deep” expedition into the deepwater areas in the Southeastern United States by NOAA in 2018. NOAA Office of Ocean Exploration and Research
The Helmet jellyfish species is very sensitive to light due to its red pigment. It lives in the much deeper parts of the oceans to avoid light.
The red pigment is very useful for warning predators and for sending signals amongst themselves. Helmet jellyfish don’t have eyes or a brain, but instead use a simple sensory bulb that detects changes in light.
This juvenile Helmet jellyfish was captured in the Trondheimsfjord in Norway in 2020 © Solvin Zankl / Greenpeace
The ghost fish is found at around 1,850 metres below the surface of the ocean. These fish are distant relatives of sharks and have skeletons made out of cartilage.
The lateral lines running across are “mechano-receptors” that detect pressure waves, just like ears. The dotted lines on the frontal portion of the face help detect disturbances in electrical fields created by other living organisms.
A chimaera, or ghost fish, is observed in the Pacific Ocean in 2017 at around 1853 metres deep during the “Discovering the Deep: Exploring Remote Pacific MPAs” expedition NOAA Office of Ocean Exploration and Research
The Whipnose angler has an enlarged first filament of its dorsal fin – called the illicium – with a bioluminescent light-emitting organ at its end.
The teeth of the Common fangtooth are so long that the fish can only close its mouth by stowing them in two cavities to the right and left of its brain.
The Whipnose angler and Common fangtooth found in the Atlantic Ocean close to Cape Verde, 2015.
Imagine these slow-moving creatures, in an environment with almost no light being confronted with an enormous, loud mining machine with headlights on each side. Deep sea mining will be hugely disruptive and could wipe out these habitats and their uniquely adapted species.
Mining could damage coral gardens and seamounts.
Sponges and corals provide shelter and food for the many creatures that live in the deep sea. Unlike tropical reefs, these cold water corals occur in depths from 80–6000 metres, forming fan- or tree-like shapes.
Due to the lack of sunlight, they get their nutrients by trapping tiny organisms that flow in the ocean’s currents.
This deep-water coral was photographed during the Lophelia II Expeditions, 2008–10 NOAA Office of Ocean Exploration and Research
Seamounts are underwater mountains that provide a perfect habitat for cold water corals and sponges. They have a big impact on the deep sea environment. For example, they generate waves, improving the food supply for filter feeders – animals that feed by straining suspended matter and food particles from water.
Here an actively venting hydrothermal vent chimney is shrouded in black smoke and covered with animals that live on these vents. Pictured during the NOAA 2016 Deepwater Exploration of the Marianas. The Mariana trench in the Western Pacific is the deepest part of the ocean. NOAA Office of Ocean Exploration and Research
We know more about the surface of Mars and the Moon than we do the deep seas. It’s estimated that 91% of ocean species have yet to be classified.
Sponges are animals that often live for thousands of years. New species of sponge are being discovered all the time. One study found that a deep-sea sponge from the species Monorhaphis chuni lived to be 11,000 years old.
This carnivorous demosponge was one of two collected from the genus Chondrocladia during the 2019 Southeastern U.S. Deep-sea Exploration as possible new species during the 2019 Southeastern US Deep-sea Exploration. NOAA Office of Ocean Exploration and Research
At the time of observation, scientists were uncertain whether this organism seen during Dive 08 of the third Voyage to the Ridge expedition was a soft coral, a sponge, or a tunicate. NOAA Ocean Exploration, Voyage to the Ridge 2022.
This Bolosoma stalked glass sponge was spotted on the Malulu Seamount during a research expedition in the National Marine Sanctuary of American Samoa. It's possibly a new species. © NOAA Office of Ocean Exploration and Research
This vibrant yellow glass sponge (Bolosoma sp.) was observed at a depth of 2,479 metres while exploring Sibelius Seamount, North Pacific Ocean 2017 © NOAA Office of Ocean Exploration and Research
This potentially undescribed Cydippid ctenophore (or Comb jelly) was seen floating gracefully in the water column during a 2019 expedition.
This comb jelly was photographed during the “Deep Connections 2019” expedition in deepwater areas of the US and Canadian Atlantic continental margin. NOAA Office of Ocean Exploration and Research, Deep Connections 2019.
Deep sea mining poses risks to ocean ecosystems and could cause irreversible damage to these unique habitats and creatures.
It took millions of years for the polymetallic nodules to form. Plundering the seabed to extract these metal deposits could not only have a direct impact on the fragile species that anchor on them, but also on other marine life.
Deep sea mining will also kick up vast sediment plumes.
If you ever played with sand in the sea, you’ll know how cloudy the water gets, and how long it takes to settle. Now imagine that over hundreds of kilometres, in an ecosystem that is used to crystal clear waters.
These sediment plumes from mining would spread through the ocean, far beyond the mining site – and risks releasing toxic elements such as heavy metals into the environment, and clogging filtration and breathing structures of some of the creatures shown above.
The Arctic Sunrise protesting against deep sea mining at the 28th session of the International Seabed Authority started on 16th March, with government delegations gathering in Kingston, Jamaica less than two weeks after the historic Global Ocean Treaty was agreed at the United Nations. The meeting was a critical moment for the future of the oceans as deep sea mining companies are gearing up to start mining – before governments have decided if the industry even has a future. © Gladstone Taylor / Greenpeace
It’s thought that deep sea mining would also threaten the ocean’s role as a carbon store, which would make the climate crisis worse. As well as threaten the lives and livelihoods of Indigenous Peoples and coastal communities that rely on the oceans.
Now is the time governments around the world must stop this dangerous extractive industry from getting a green light to start full scale mining.
Header image: A sea toad pictured near the Wake Atoll in the Pacific Ocean in 2016, waiting for its next meal to swim by. ©NOAA
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