Scientists Find Animals Under the Sea, Give Clues to Extraterrestrial Life

A research team has discovered macroscopic life under the deep sea, one of the most dangerous places on earth.

These findings both complicate scientists’ understanding of living communities around deep-sea hot spots, and provide a fascinating glimpse into what life might look like beyond Earth. Although researchers knew that life existed in and around the vents, whether organisms used the sediment miles below the ocean itself was unclear.

In their latest work—published today in Nature Communications—the team used a remotely operated vehicle Subastian on a research vessel Falkor (again) to identify animals usually associated with deep-sea hot spots in the subsea—that is, under the sea. The team conducted their investigation about 8,250 feet (2,515 meters) below the sea floor in an area they named the Fava Flow Suburbs in the eastern Pacific Ocean.

“What we found shows us that marine animals are not limited to what we see in the ocean, but those animals extend to the shallow ocean,” said co-author Sabine Gollner, a researcher at the Royal Netherlands Institute. In Marine Research, in an email to Gizmodo. “The extent of the subsea holes—horizontally and how deep they go—is not known yet,” Gollner added. “The sub-sea habitat may be more important for succession in tropical regions, as the sub-sea and sub-sea habitats are connected.”

The team discovered that animals such as tubeworms move through holes under the sea to get from Point A to Point B. Specifically, the team identified tubeworms. R. pachyptila again O. alvinae and mussels B. thermophilusand polychaete worms and limpets, among the burrowing species.

To get a feel for the conditions under the sea, the team used SubastianA tool kit for drilling small holes into pieces of igneous rock on the sea floor. The sub also lifted up parts of the lava shelves to see what lay beneath. Before lifting the shelf, the team took a sample of the vent fluid from the holes they drilled, measuring the temperature inside the holes (which was about 64° Fahrenheit, or 18° Celsius, on average).

Beneath the 4-to-6-inch (10 to 15 cm) lava shelf, the team identified 4-inch-high (10 cm) cavities where tube worms and mussels lived. Some of those living under the sea were obviously old people; at least one worm was more than 41 centimeters long, indicating that the burrows were more than just a nursery. As adults, tubeworms lose their mouths and intestines and rely on bacteria Candidatus Endoriftia persephone for nutrition, which lives inside worms. With the temperatures available inside the deep sea caves, and their food source in the worms themselves, the giant animals were able to survive in the most dangerous environment without any problem.

There are few necessities of life as we know it. Water, carbon, nitrogen, luck—there are a number of elements that appear to be necessary for life, and which guide the search for life beyond Earth, a field of science called astrobiology. By probing some of Earth’s most dangerous environments, scientists hope to better understand the kinds of conditions that might support life everywhere from distant exoplanets to the oceans beneath Jupiter’s icy moons.

“The study of the subseafloor biosphere for animal life is just beginning,” the group wrote in the paper. “These efforts will lead to a better understanding of hydrothermal vent biogeochemistry, ecology, and evolution and their impact on global biodiversity, as well as linkages, which may lead to better management of oceanic and crustal subseafloor hydrothermal vents.”

Last year, a team using the same vessel discovered new thermal vents teeming with life on the ocean floor. The Schmidt Ocean Institute coordinated that effort, which highlighted the need to protect such areas rich in marine minerals, which could be targeted for deep-sea mining operations. That same year, Falkor (again) was used to locate an octopus nursery deep off the coast of Costa Rica.

“The diversity of active hydrothermal vents is well recognized, and protection against potential anthropogenic impacts such as deep-sea mining has been proposed or is in place,” the team said. “The discovery of animal habitats in the crustal subseafloor, the extent of which is currently unknown, increases the urgency of this protection.”

The ship Falkor–Falkor (again)the predecessor—he enlightened us about the almost identical organisms that exist at the bottom of the sea. In 2021, a crew aboard the ship found microbes in the deep sea that are invisible to the human immune system, indicating that our bodies’ ability to detect foreign microbes is not all-encompassing. Apart from these forms of life that are so alien to our normal senses of life, they are so unlike us that our bodies cannot even recognize them as living things.

Recent discoveries may help you in your search for extraterrestrial life. If creatures can make happy homes in the seabed, it widens the range of life that can exist in the deep sea. Sure, we may be alone in the galaxy, but the universe is a big place, full of possibilities.

Take a study published in PNAS Nexus back in April, for example, that discovered an ecosystem teeming with life beneath Chile’s Atacama desert. The Atacama is an arid region in northern Chile that is one of the least hospitable places on Earth. However, the team leading that study found several classes of bacteria found underground. Bacteria are protected from the ultraviolet rays of the surface under the soil, but remain close enough to obtain the energy for photosynthesis.

It is not yet clear how deep the life under the sea can continue, but it is clear that several macroscopic species make it work. The team wrote that “due to the increase in temperature, it has been predicted that life should be a few meters below the ocean.” Future studies can determine precisely under what conditions it is not suitable for life.

The findings could hold water (no pun intended) as scientists peer beneath Jupiter’s icy moons Europa and Ganymede, which are thought to have underground oceans. Even if alien life isn’t floating in the water column, recent discoveries may show it’s worth digging–or diving–deep to find it.