Ranger Rani, like the scientists, is stunned! She has seen creatures live in ice and cold. Creatures also live in extremely arid conditions. Ranger Rani has seen creatures in boiling thermal vents and frozen icebergs.
But nobody imagined any living creature could live in the depth of 5,000 m in the sea. Today scientists know that an astonishing number of species, 17,650 to be precise, live in deep sea. They breakdown oil, sulfur, methane, bones of dead whales and other foods we can't imagine.
At about 2,500 m scientists identified deep sea eels, Neocyema. Very little is known about the species and this is the first time scientists have identified the species from so deep. The rat-tail fish lives in the seafloor between 1,700 to 4,300 m. This fish is famous for having otoliths, tiny bones in the ear. When the fish grows, the bones develop growth bands that can be counted like tree rings. Scientists know the age of specimen based on the number of growth bands.
Another surprising find was an octopus relative called 'Dumbo.' In seafloor at 1,000 to 3,000 m, finned octopods were collected. These are primitive relatives of the modern octopus. 'Dumbo' is a cartoon elephant that can fly using ears. The octopod flaps a pair of ear-like fins to swim!
On the seafloor of Gulf of Mexico (about 600 m), the robotic arm plucked out a tubeworm from a hole. As soon as the worm was removed, crude oil streamed from the animals. Scientists were astonished to see the crude oil streaming from the tubeworm. The tubeworm was dining on decomposing oil!
Deeper still in the Northern Gulf of Mexico (about 2,750 m), scientists captured a transparent sea cucumber in action. Creeping forward slowly on its tentacles, the sea cucumber swept the sediment into its mouth. The microbes and crustaceans in the detritus-rich sediment was the food for this sea cucumber.
Even the frigid waters of Antarctic houses many species of whalebone-eating worms, Osedax. More than 17 species of Osedax is recorded from shallow sea beds (about 500 m) to the deep seas. In an interesting experiment, scientists placed whalebones at different depths 550 m and 630 m. After 14 months, they found that several species of whalebone-eating worm, one new species was recorded.
Ranger Rani thinks the scientists are brave. Can you imagine working in sea swells of 10 m high? Can you sit for hours to send the remote vehicle on the sea floor? Once the equipment is in place, scientists have to decide the best spot to sample. Their work is daunting.
It's impossible for humans to dive at the depth. Deep sea studies are expensive requiring cooperation of several nations to make the complete study. We don't know the underwater topography until we actually explore the area. That makes deep sea exploration exciting.
Scientists think that there is plenty to learn from the deep sea. If we collect one coffee-cup sized sample of the deep-sea sediment, we won't be able to identify all species collected.
The deep sea is a mysterious place. We don't know the underwater topography. Ridges, mounts, water temperature and currents are all seen and unseen barriers that determine supplies of food and define the species distribution in the deep sea.
What does it take for a successful deep sea community to thrive?
Scientists short list four important requirements. First, there should be abundant food in higher layers of the ocean that settle to the floor or stay at the depth where animals can migrate to get it. Second, the animals should be long-lived and populations can grow on meager diet. Third, swift water current brings more food to the animals and fourth, alternative food production paths like chemosynthesis should be available to animals.
There is so much to learn about the deep sea. Ranger Rani hopes one day some of you will work on the project. Until then, let us protect the deep sea from drilling and mining.
