The deepest point of the Earth that life has been foundwould be Challenger Deep, the deepest part of the Mariana Trench in the Pacific Ocean, that plunges down 11,000 metres or 2,000 metres more than Mount Everest is high.
Here 5cm-long shrimp-like amphipods Hirondellea gigas survive on tree and plant debris that has sunk to these extreme depths, living alongside giant sea cucumbers and amoebas called xenophyophores.
- How deep is the deepest part of the ocean?
- At a staggering 3500m below sea level, this frozen abyss is the deepest, darkest and least explored place on land...
Is there anything else down that deep?
Yes, an expedition in 2012 collected samples at 10,677 metres that are evidence of microbial mat communities, layers of micro-organisms that grow like a carpet over rocks or mud. Scientists describe these micro-organisms as chemolithoautotrophic and they derive their energy from hydrogen released by geological processes that are unique to these extreme environments. Other scientific studies have speculated that similar processes could lead to life on other planets such as Mars.
- Could any animals live on other planets?
- What could aliens look like? How could evolution work on other planets?
Are there any vertebrates at these extreme depths?
Not at the very bottom of the Mariana Trench, but the “small, pink and scaleless” Mariana snailfish can be found at 8,000 metres, where it is the dominant predator! The trench, by the way, is not only considerably deeper than Everest is tall, it’s also much larger and wider – more than 2,500km long (five times the length of the Grand Canyon) and on average, 69km wide.
Are there any other interesting lifeforms at such extreme depths?
Yes, research published in 2024 reported evidence of polychaete worms and bivalve shellfish that survive through chemosynthesis at depths of up to 9,533 metres. The discovery was made in the Kuril-Kamchatka Trench in the north-west Pacific and include these polychaete worms which live in tubes 20-30cm long. These lifeforms are sustained by metabolising fluids rich in hydrogen sulphide and methane.
- Scientists drop cameras 9,100m deep off coast of Japan. What they find baffles them
- It's the lowest place on Earth, the size of Seoul, 10 times saltier than the ocean – AND it's dying. One day soon it might not be here...
Where are the deepest living organisms on dry land?
They are not as far down, but they are still living in very extreme environments. In the Mponeng gold mine near Johannesburg in South Africa a bacterium called Desulforudis audaxviator is found at a depth of 2,800 metres, and it not only survives in complete isolation from any other species, but also in total darkness, without oxygen and in temperatures of 60˚C, according to scientists from Berkeley Lab.
Their research has shown that none of its energy is derived from energy from the sun (via photosynthesising plants, the way in which the vast majority of life forms survive), but from hydrogen and sulphates produced as a result of decaying radioactive uranium.
Not only that, but the bacterium has evolved to make its own organic molecules by getting carbon from inorganic sources such carbon monoxide and carbon dioxide. It’s species name – audaxviator – is taken from a line in Jules Verne’s famous work, Journey to the Centre of the Earth which reads, “Descende, Audax viator, et terrestre centrum attinges” – and aptly translates into, “Descend, Bold traveller, and attain the centre of the Earth.”
Is there much life deep below the surface of the Earth?
A surprising amount. One study estimated 23 billion tonnes of bacteria and other organisms living in the deep biosphere, including what the scientists called “zombie” microbes that were barely alive. “There is life everywhere, and everywhere there’s an awe-inspiring abundance of unexpected and unusual organisms,” Mitch Sogin of the Woods Hole Marine Biological Laboratory. Though these life forms consist almost entirely of bacteria and archea (a group of micro-organisms unrelated to bacteria but often similar in size and and shape), but there is a remarkable genetic diversity that is comparable to life above the surface of the Earth.
