• Leo R

A Brief History of Deep Sea Exploration

Updated: Nov 18, 2020

Humanity is driven forward by a desire to discover and make sense of the world around us. The deep sea represents the unexplored frontier of discovery, for only recently has the appropriate technology existed to allow us to dive to these depths and document our findings on film.

Above is the ROV Hercules, a remotely operated vehicle aboard the E/V Nautilus, a marine research vessel that is part of the Ocean Exploration Trust. The submersible is routinely deployed to depths of up to 4,000 metres to collect samples and recover artefacts. It is this new technology that has enabled us to delve deeper and uncover greater secrets from the deep.


Click here to read the 2019 report of their findings, along with those from the NOAA ship Okeanos Explorer, and the R/V Falkor.



The ROVs have been able to capture an abundance of unique and fascinating footage and photographs in astounding quality, of what appears to be another world below the waves. Each year, the expeditions yield discoveries of previously unknown species, and allow us to observe unseen behaviours in marine life.

The above photograph shows a specimen that was collected from one of the ROV dives. It is a colourful sea fan, a colony of tiny coral polyps that join together to form these branching structures. Growing in this way allows the polyps to spread outwards into open waters to catch plankton drifting on currents.


But where did deep sea exploration begin?


1521 - Portuguese explorer Ferdinand Magellan became the first man to try and measure the depth of the Pacific Ocean. He threw a 2,400-foot long weighted line off the side of the boat. It never reached the sea floor.

1818 - Explorers captured worms and jellyfish for the first time from depths of 6,550 feet, providing the very first evidence for deep sea life.

Around this time, it was believed that the deep sea was too harsh and barren to support life at all.


1842 - Naturalist Edward Forbes proposed his 'Abyssus Theory', in which he argued that biodiversity decreases with depth, and life will not be able to survive below 1,800 feet. We have since come to realise that this was not the case.

1850 - A diverse ecosystem was uncovered by biologist Michael Sars, thriving at 2,600 feet below the waves. His later discovery of the first living stalked crinoid spurred academic interest in the exploration of the deep sea. This was the catalyst that prompted the Challenger expedition between 1872-1876.


Led by Charles Wyville, the HMS Challenger set out on the first deep sea exploration mission. Many new species were discovered, displaying unique adaptations in order to survive in the deep sea. It was these findings that proved definitively that the Abyssus Theory was incorrect, and the depths were able to support a highly complex community of life.



Only in recent times have we fully begun to understand the processes taking place in the deep sea. Hydrothermal vents were first discovered in 1977, and they host a community of organisms relying entirely on energy produced by the earth itself, rather than sunlight. This goes to show that we are still only scratching the surface. What else is down there, in wait of discovery?

View our Deep Sea Hub for facts and news about this haunting realm.


Read more about Deep Sea Exploration here.

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