Horror and the deep blue sea

Twenty Thousand Leagues Under the Sea published in 1870 by French writer Jules Verne can be considered the first story to introduce the life-forms of the deep blue sea to the public, even if the title is a reference to the distance traveled by the "Nautilus", not the reached depth. The novel was adapted into various movies since 1907. Probably the most well-known adaptation is the version of 1954 with the quite charming special effects and marine scenery.A darker approach to the sea was adopted in the 1989 science fiction movie The Abyss, where the crew of an experimental underwater oil platform encounters strange life forms in a depth of more than 5.500m. The expected success of the movie (the production was so elaborate that the final release was postponed) generated a lot of copycats: Leviathan (1989), DeepStar Six (1989), The Evil Below (1989), Lords of the Deep (1989), and The Rift/Endless Descent (1989) - all these movies follow a very similar plot: the crew of a submarine or underwater station is entrapped with an unknown life form (alien, mutant, sea monster, prehistoric monster) in a confined space. Proteus (1995) and Deep Blue Sea (1999) tried a decade later to revive the genre of underwater horror. DeepStar Six is insofar interesting as the main monster is a surviving prehistoric eurypterid.

Since antiquity, the unknown regions of the oceans were populated by terrible monsters.

Only with the beginning of the age of exploration in the 15th century almost all the monsters vanished slowly from the maps, but still until the 19th century the sea floor remained unknown. It was considered almost impossible that life forms could survive in an environment without light, low temperatures and high pressure. With the first submarine telegraph cables in the mid of the 19th century, it was discovered that life existed also in great depth, as the cables when lifted back to the surface were encrusted by organisms.
The Challenger expedition (1872-1876) was an ambitious research project that recovered samples of the sea floor and described for the first time the life forms of the abyssal zone (4.000-6.000m). However apart from these single glimpses there was no possibility to explore and observe this extreme and vast environment.

January 23, 1960, two men, Jacques Piccard and Donald Walsh, observed for the first time the seafloor at a depth of 10.916m in the Mariana Trench. They were surprised to observe various species of fishes and crustaceans swimming around.

In 1977 the crew of the submarine "Alvin" discovered life forms that dwelled in a self-sufficient ecosystem on a volcanic spot in the eastern Pacific, known as the Galapagos Rift. The hot fluids coming from the hydrothermal vents provided nutrients and minerals used by certain bacteria species to acquire energy from chemical reactions. These bacterial mats provide the base of the ecosystem; some organisms, like giant clams and worms, also host the bacteria in special apposite organs and feed on them. The movie Leviathan (1989) features giant tube worms.
 

Research in the last years has shown that the assemblage of organisms differs between the single spots with hydrothermal vents. For example the classic tube worms Riftia pachyptila and giant clams Calyptogena magnifica are found only in the eastern parts of the Pacific Ocean. In the Scotia Sea we find the "Yeti-Crab" Kiwa hirsute. Based on the species-association at least eleven types of hydrothermal vent biota were proposed.