Where Can You Find Hydrothermal Vents?
Hydrothermal vents occur around geologically active areas on the ocean’s floor, and are a result of magma seeping up out of the mantle of the earth into the ocean. These vents are responsible for the creation of underwater mountain ranges and also contribute to tectonic activity.
Black and White ‘Smokers’
At first glance, thermal vents look like giant chimneys, billowing a black, sometimes white, smoke into the surrounding water. This ‘smoke’ is actually highly mineralized water! The ‘chimney’ formations are a result of the highly mineralized water being pushed up out of the earth, and meeting and mixing with much colder water. When the two extreme temperatures meet, mineral deposits form, and harden quickly. Depending on the geology of the surrounding area, the depth of the vents, and the types of minerals escaping from the vents, the color of the smoke can vary. For example, black smoke is usually indicative of water that is heavy in sulphides. Although many different types of thermal vents occur around the world, the sheer diversity of organisms sets Antarctica apart from the rest.
Getting to the Vents
Designing recording devices to withstand not only the intense pressure of the ocean depths, but the highly variable temperatures around hydrothermal vents is an obstacle that until recently was difficult to overcome. When the technology to reach these parts of the ocean became available, oceanographers at Oxford and the British Antarctic Survey deployed an ROV (remotely operated vehicle) in the murky depths of the Southern Ocean along the Scotia Ridge near the Antarctic Peninsula. Once it reached its destination, the ROV began recording everything it encountered. What it found came as a shock to researchers.
Is There Life in Antarctic Hydrothermal Vents?
What could possibly stand to live at the bottom of the ocean where toxin-rich, boiling hot water that reaches temperatures of up to 400°C (700°F) spews forth out of the earth, only to be met with unbearably freezing cold Antarctic water? Life can’t be easy. Sure enough, there is an entire ecosystem that has managed to withstand these extreme living conditions.
The yeti crab, named for its unusually hairy extremities, is one of the many recently discovered species found to inhabit the hydrothermal vents. At 2,400 meters (7,874 feet) below the surface of the ocean, there isn’t much free-floating debris or food items to prey on. Instead of waiting for food to come its way, the yeti crab grows its own food with bacterial mats located on its chest and arms. These little crabs are essentially their own farms. Imagine being able to sustainably grow your own food on yourself! The many species of bacteria that grow on the yeti crabs converts the many chemicals that are emitted from the vents into usable energy. This process, chemosynthesis, sustains life in lightless, nutrient-deficient ecosystems such as deep-sea hydrothermal vents.
Living at the bottom of the ocean can have its perks. The deep-sea thermal vent octopus, or just “ghost octopus” surprised researchers with its hauntingly translucent skin, and pitch-black eyes. At these depths, there’s no need for this octopus to have pigmented skin, which helps it camouflage from predators. There’s simply nothing that wants to eat it! It is, however, a predator of the few mollusk and snail species that occur in its habitat. Its dark eyes are most likely attributed to its low-light environment. Since there’s hardly any light that penetrates these depths, its irises are enlarged, and take up most of the space in their eyes. Luckily, these octopodes (the correct plural for more than one octopus!) have eight legs to help them move around the ocean floor.
Life has found a way to persist in what is essentially a year-round spa. As the two extremely hot and cold waters combine, they create an area that is ideal for life. One step too close to the outpouring hot water or icy seawater is certain death for any living thing. Scientists have referred to this ideal area for life as the “goldilocks zone”. Not too hot, and not too cold. All of these vent-dwelling creatures are often referred to as extremophiles, or organisms that are capable of living in unusually harsh or challenging environments.
What Do These Discoveries Mean for Science?
The mysteries of the ocean remain vast and deep. The discovery of an impressively vast ecosystem around Antarctic hydrothermal vents has confirmed what scientist around the world have already comes to term with. There’s an indescribably impressive world of organisms inhabiting the ocean that we have yet to discover. Certainly, there are limitations to where and when humans are able to explore these places and species. The Southern Ocean, for example, is not only difficult to get to, but inclement weather and tumultuous conditions at sea are two very good reasons why that particular area hasn’t been thoroughly explored yet. It’s amazing to think of the life on earth, especially in the ocean, that has yet to be described by science. If life has the ability to exist in the most dark, hot, toxic places on earth, think of where else it could exist! The possibilities are truly endless.