What lies beneath: Interactive graphic reveals the creatures and shipwrecks that lurk in the deep sea - as study reveals we still don't know what's hiding on 99.999% of the ocean floor

Daily Mail​

07-05-2025

From long-lost shipwrecks to bizarre forms of life, Earth's oceans are teeming with untold mysteries.
Yet despite decades of exploration, a study published in Science Advances has shown we still don't know what is lurking in 99.999 per cent of the deep ocean.
Since 1958, 44,000 dives have only visually observed an area one-tenth the size of Belgium.
Scientists say this is equivalent to trying to learn about every ecosystem on land by looking at an area the size of Houston, Texas.
Now, an incredible interactive graphic reveals what lurks in this strange world beneath the waves.
Defined as being deeper than 200 metres (656ft), the deep ocean makes up 66 per cent of the surface of the planet.
However, researchers from Ocean Discovery League now say that our understanding of the ocean's depths is woefully inadequate.
Dr Ian Miller, chief science and innovation officer at the National Geographic Society which provided funding for the study, says: 'There is so much of our ocean that remains a mystery.'
As this interactive graphic shows, Earth's oceans are divided by depth into different zones: the epipelagic, mesopelagic, bathypelagic, abyssopelagic, and hadalpelagic.
The epipelagic, also known as the sunlight zone, is the very top layer of the ocean where visible light can still be found.
Extending down to 200 metres (656 ft) below the surface, the epipelagic zone is home to many familiar species such as dolphins, sharks, turtles, and whales.
Photosynthesising plankton in this layer produce 50 per cent of the planet's oxygen and are a key part of the ocean food chain.
However, despite this region being the main focus of human marine activity, it only makes up a small part of the total ocean.
In fact, 50 per cent of the planet is covered by ocean which is at least two miles (3.2 km) deep.
Just below the sunlight zone is the mesopelagic zone, also known as the twilight zone.
This region extends from 200m to 1,000m (3,280 ft) deep, where light cannot reach at all, and some studies suggest it might contain 10 times more biomass than the other ocean zones combined.
However, scientists' knowledge of what lies in these deep ocean zones is exceptionally slim.
Looking at recorded dives since 1958, the researchers found that humanity has visually observed an area of deep ocean no larger than Rhode Island.
Given that not all dives are public, the researchers say their figure is at the low end of estimates.
However, even if they were off by an order of magnitude, humanity still would have seen less than a hundredth of a per cent of the deep ocean.
To make matters worse, the recorded observations we do have are often low quality or inaccessible to the scientific community.
Almost 30 per cent of all documented observations were taken before 1980 and so only resulted in low-quality black and white images.
A large part of that imagery collected over the last seven decades is not accessible to scientists since it is either not digitised, still stuck on hard drives, or not catalogued.
Additionally, the researchers point out that humanity's attempts to explore the deep oceans have focused heavily on just a handful of tiny areas.
97 per cent of deep-sea expeditions since the 1950s have been conducted by researchers from Germany, France, Japan, New Zealand, or the US
The records reveal that over 65 per cent of all observations have taken place within 200 nautical miles (370 km) of the US, Japan, or New Zealand.
Due to the extreme costs of ocean exploration, research teams from the US, Japan, New Zealand, France, and Germany were responsible for 97 per cent of all observations.
These expeditions have also tended to favour certain habitats such as ocean ridges and canyons, leaving the vast areas of the abyssal plains and seamounts unexplored.
This limited exploration means there is likely to be an incredible diversity of life that is totally missing from our understanding of the ocean.
For example, scientists discovered over 5,000 new species in just one underexplored zone.
The researchers point out that these little-known areas could provide the planet with climate regulation, a source of oxygen production, and even crucial pharmaceutical discoveries.
Just last year, scientists discovered that metals 3,900 metres (13,000 ft) below the surface produce 'dark oxygen'.
This discovery challenged long-held assumptions that only photosynthetic organisms could produce oxygen and could call into question how life on Earth began.
However, the scientists who made the discovery also warned that new deep-sea mining could disturb this poorly understood mechanism.
Without more knowledge of the underwater environment, scientists still don't know exactly what impact this might have on the wider ecosystem.
Lead researcher Dr Katy Croff Bell, president of the Ocean Discovery League, says: 'As we face accelerated threats to the deep ocean—from climate change to potential mining and resource exploitation—this limited exploration of such a vast region becomes a critical problem for both science and policy.
'We need a much better understanding of the deep ocean's ecosystems and processes to make informed decisions about resource management and conservation.'
DEEP-SEA DEBRIS DATABASE REVEALS EXTENT OF OCEAN PLASTIC POLLUTION
Plastic pollution is a scourge that is ravaging the surface of our planet. Now, the polluting polymer is sinking down to the bottom of the ocean.
The deepest part of the ocean is found in the Mariana Trench, located in the western Pacific Ocean, to the east of the Mariana Islands. It stretches down nearly 36,100 feet (11,000 metres) below the surface.
One plastic bag was found 35,754 feet (10,898 metres) below the surface in this region, the deepest known piece of human-made pollution in the world. This single-use piece of plastic was found deeper than 33 Eiffel towers, laid tip to base, would reach.
Whilst the plastic pollution is rapidly sinking, it is also spreading further into the middle of the oceans. A piece of plastic was found over 620 miles (1,000 km) from the nearest coast - that's further than the length of France.
The Global Oceanographic Data Center (Godac) of the Japan Agency for Marine-Earth Science and Technology (Jamstec) launched for public use in March 2017.
In this database, there is the data from 5,010 different dives. From all of these different dives, 3,425 man-made debris items were counted.
More than 33 per cent of the debris was macro-plastic followed by metal (26 per cent), rubber (1.8 per cent), fishing gear (1.7 per cent), glass (1.4 per cent), cloth/paper/lumber (1.3 per cent), and 'other' anthropogenic items (35 per cent).
It was also discovered that of all the waste found, 89 per cent of it was designed for single-use purposes. This is defined as plastic bags, bottles and packages. The deeper the study looked, the greater the amount of plastic they found.
Of all man-made items found deeper than 20,000 feet (6,000 metres), the ratios increased to 52 per cent for macro-plastic and 92 per cent for single-use plastic.
The direct damage this caused to the ecosystem and environment is clear to see as deep-sea organisms were observed in the 17 per cent of plastic debris images taken by the study.