The geography of a canyon also creates currents of moving water that suspend the amassed nutrition into the water column, often even reaching up into shallower, sunlit depths where photosynthetic algae grow. Krill and crustaceans called amphipods thrive off the phytoplankton, and it is the masses of these zooplankton that attract tuna, swordfish, and sharks to canyons. But as the Rocky Mountains began to rise and subsequently erode, the extra weight of the sediment flushed into the Gulf of Mexico via the Mississippi River was enough to break the seal.

Finding Food

Fish, too, find shelter within the canyon walls, and also a good place to catch a meal. Natural light does not penetrate the deep ocean, with the exception of the upper parts of the mesopelagic. Since photosynthesis is not possible, plants and phytoplankton cannot live in this zone, and as these are the primary producers of almost all of earth’s ecosystems, life in this area of the ocean must depend on energy sources from elsewhere. Except for the areas close to the hydrothermal vents, this energy comes from organic material drifting down from the photic zone. The sinking organic material is composed of algal particulates, detritus, and other forms of biological waste, which is collectively referred to as marine snow. Deep-sea fisheries take place between depths of 200 and meters, and target species on continental shelves, seamounts and ocean ridges using bottom and deep mid-water trawls, gillnets, longlines and pots.

Giant sea spider

The extreme saltiness causes significantly denser water than the average ocean water and, like water and air, the two do not mix. The salt difference is so definitive that sitting above the brine lake, you can visibly see the lake’s surface—even waves when the lake is disturbed. Salinity is remarkably constant throughout the deep sea, at about 35 parts per thousand.9 There are some minor differences in salinity, but none that are ecologically significant, except in largely landlocked seas like the Mediterranean and Red Seascitation needed. Undiscovered oil reserves in the region have been estimated at 801.5 million cubic metres (5,041 million barrels). Undiscovered gas reserves in the region have been estimated at 3,180 billion cubic metres (112,349 billion cubic feet).

Deep sea

This, he said, could wipe certain pelagic species out before deep-sea mining even begins on a commercial level. For Warwick, the bigger concern is for benthic species, which are slower growing. “Because of their habitat use, deep-sea mining could be almost as great as deliberate killing of them through fishing,” Warwick told Mongabay. While commercial deep-sea mining has not yet started, some companies are looking to launch operations in the near future.
On the other hand, the more food-limited Ryukyu Trench at this depth was dominated by very different communities with sea cucumbers nearly absent. Deep-sea creatures in the trenches of Japan’s volcanically active “Ring of Fire” belt are rapidly adapting to immense depths, scientists found. Noise and light pollution could seriously disrupt species, such as whales and other deep-diving or deep-dwelling animals, that use noise, echolocation or bioluminescence to communicate, find prey and/or escape predators. Alongside legal and extractive frameworks, alternative imaginaries—such as those inspired by Drexciyan mythology—disrupt dominant logics of ownership and exploitation.

• Dive deeper and the weight of the water above continues to accumulate to a massive crushing force.
• Judah pointed out that while the research drew from the most complete data available from the IUCN, much of the deep sea remains unexplored, so the study’s findings likely underrepresent the risks chondrichthyan species face.
• They are deployed from a research vessel, scan a predetermined route independently, taking readings at regular intervals, and then surface again at fixed coordinates for retrieval.
• It will probably be integrated into the broader domain of the anthropology of the ocean.
• For example, in the central Arctic Ocean, a research team including AWI staff was surprised to discover lush gardens of sponges growing on dormant underwater volcanoes.

While there has been commercial interest in these minerals for decades, recent advancements in technology have made it feasible to mine these areas by sending vehicles down to harvest mineral deposits from the seafloor. The sensory modes through which the deep sea has been scientifically understood have evolved over time—from the tactile to the auditory and, finally, to the visual (Helmreich 2009). This progression has made the submarine world simultaneously more comprehensible and more fantastical (Helmreich 2009). To gain experience of the deep sea, anthropologists and other social scientists rely on the same technical aids as the oceanographers with whom and through whom they study. This medium of engagement ‘blurs distinctions between inside and outside, artifice and environment’ and is simultaneously ‘hyper-present and invisible’, much like the water surrounding the submarine itself (Helmreich 2009, 214).
Depending on their payload, they can e.g. monitor flow direction and speed, the water’s oxygen content, or the number of particles that make their way to the deep from the surface. At this point, we have a fairly good idea of the seafloor’s topography, complete with plains, ridges and trenches – because experts have used echosounders to survey its depth profile and created corresponding maps. However, less than one percent of the seafloor has been examined in detail – e.g. with regard to the fauna living there.

Council’s hands ‘completely tied’ on land access

A second has been observed on video, however, it has yet to be captured and formally described. Despite the remoteness of the Deep Sea hadalpelagic, humanity still finds a way to interfere—plastic debris has been found at the bottom of the Mariana Trench. Oceanographers divide the majority of the ocean midwater into five broad zones. The very deepest depth of the ocean is roughly 2,000 meters deeper than Mount Everest is tall—36,070 feet deep (10,994 m)! Each zone has a different mix of species adapted to its specific light level, pressure, temperature, and community.

• The construction of a speculative seabed archive through the language of common heritage can thus, practically speaking, become a tool of colonization.
• For several decades, coastal states have been permitted to submit claims to the Commission on the Limits of the Continental Shelf (CLCS, established in 1997) to extend their continental shelf.
• These nodules provide a mosaic of hard substrate for a variety of organisms such as corals and sponges, and support diverse deep-sea communities.
• Despite their small size (some no bigger than a mosquito), these creatures can travel hundreds of meters in just a few hours.
• Each species plays a role in the delicate balance of marine ecosystems, highlighting the importance of protecting this incredible part of our world.
• Nodules also host a vast array of microbial communities that play a critical role in nutrient and carbon cycling.
• Deep-sea ecosystems are amongst the least well understood owing to the combined challenges of remoteness, vastness, and the difficulties of exploring its depths.

These locations venture into the hadalpelagic zone, places so deep only a handful of humans have ever traveled there so far. Most are familiar with the surface layer, which extends down 650 feet (200 m) and receives the most sunlight, allowing photosynthetic organisms like phytoplankton to convert sunlight to energy. In 1960, the bathyscaphe Trieste descended to the bottom of the Mariana Trench near Guam, at 10,911 m (35,797 ft; 6.780 mi), the deepest known spot in any ocean.

What’s best for Earth? The debate over deep ocean mining

In addition, fish rely on their lateral line organ, which allows them to detect even the smallest changes in currents and pressure to locate obstacles or other animals moving nearby. And last but not least, many deep-sea organisms have large eyes, helping them pick up the tiny amounts of residual light in the water or the light signals put out by other fauna. A seamount is an underwater mountain that can rise thousands of feet above the seafloor.
However, mining them is a technically complex and correspondingly expensive undertaking. As such, there have only been pilot projects; there is no commercial mining network. But many countries and private companies have already applied for exploration licenses with the United Nations’ International Seabed Authority. For observations, experiments and taking measurements directly on the seafloor, “bottom landers” are a good choice – devices that, without a cable, sink down to the seafloor, where they take pictures and conduct pre-programmed experiments.

Red Sea

However, because the highest concentration of rare earths is thought to be in international waters, the ISA holds significant regulatory power over deep-sea mining. Yet, the ISA is still developing its official policy on how it will approach deep-sea mining regulation, and it has not approved any extraction projects. As of August 2025, the ISA has only issued 31 exploration contracts, which are 15-year contracts that allow countries and corporations to assess the potential for rare earths in certain approved locations.
A few countries have already approved permits to explore mineral resources in their own domestic waters (known as “exclusive economic zones,” or “EEZs”). However, most deep-sea mining interest is concentrated in international waters. This means the industry’s future will largely hinge on how the ISA decides to regulate it. Despite years of negotiations, the ISA and its membership have been unable to agree on rules that will govern commercial mining operations in international waters.