The Okeanos Explorer: Part 1 of the adventure
The Mariana Trench. Many kilometers long, it contains the deepest point of any ocean called the Challenger Deep at 10,989 m, which is enough to easily swallow Mt. Everest. With no natural light, just barely above freezing temperatures and tons of pressure, it is largely unexplored and contains many geological and biological mysteries that scientists around the world are anxious to discover. Located in the Pacific Ocean, the Mariana Trench is 6,400 km from Hawaii, 2,200 km from the Philippines and 1,800 km from Papua New Guinea.
The Mission…
Like Captain Nemo, going 10,000 leagues under the sea, the crew aboard the NOAA Ship Okeanos Explorer, has just finished their first leg of a four-month long exploration of the Mariana region. The crew’s goal is to map the trench and its surroundings, do some site characterization and reconnaissance and to take some geological and biological samples, all to better understand the ocean’s ecology and better manage and protect its resources. The thing that makes this expedition even better is the fact that it is all online for scientists on dry land. This means that you and I can watch and discover along.
The Okeanos Explorer has been tricked out with all kinds of gadgets that allow live images (and other scientific data) to be broadcast from Remotely Operated Vehicles (ROVs) on the sea floor, bounced off of satellites and high-speed internet pathways, to the world above. The mission has now begun its second leg, after having experienced a few delays, but you can now watch the live video feed and even hear the scientists and explorers on and off the ship, all from the comfort of your own home,office, classroom, smartphone, iPad, tablet—whatever you like! Click here for the link to these incredible videos.
So what have they been up to so far?
The first leg of the mission started on April 20, 2022 and ended on May 11, 2016. The goal of this particular leg was to map and identify resources in the Mariana Trench, the volcanic arc and the back-arc of the Mariana region. As I mentioned earlier, the second leg has been delayed, but was originally scheduled to start May 20 and run to June 11, 2016. Keep checking that link for the start date of the second leg.
New species of deep sea jellyfish. Image courtesy of NOAA Office of Ocean Exploration and Research, 2016 Deepwater Exploration of the Marianas.
As you can imagine, some new species of deep sea life have been seen and documented in their natural habitat. This is invaluable to researchers as there is only so much one can learn from a dead and preserved specimen. Being able to watch them in their own world is a treat.
One of the neatest discoveries was a deep sea jellyfish, seen here in the picture to the right. It was found at a depth of over 3,000m deep. While they were observing it, they noticed it would typically stop moving with its tentacles splayed out around it, suggesting the jelly is likely an ambush type predator.
Have you ever heard of a siphonophore before? These incredible creatures are in fact a colony of many different animals living together, cooperating as a unit to feed, breed and defend against predators. The crew caught some amazing video of a “dandelion siphonophore” swimming, which is very cool as they are usually observed anchored to the sea floor!
Some other highlights in the biodiversity of the deep were discovered when an ROV was baited and sent into the Sirena Deep, which is the second deepest part of the Mariana Trench at a depth of 10,545 m. Species of rat-tail fish, giant shrimp, eels, snailfish and gigantic amphipods were all documented and video was taken of their feeding behaviours. Watch the YouTube video here!
Dives on the Mariana back arc
The Mariana back arc is an area of the sea floor called a rift valley, which means it is where two tectonic plates meet but are spreading apart. This where you’d find a lot of volcanic action and the ever famous hydro-thermal vents.
Mariana Back Arc. Image courtesy of NOAA Office of Ocean Exploration and Research, 2016 Deepwater Exploration of the Marianas.
The crew actually went looking for an area of hydro-thermal vents that were described by another scientific team, but due to lack some exact coordinates they weren’t able to find them. But on their last dive they hit the hydro-thermal jackpot!
Hydro-thermal vents that were over 30m high, found at a depth of 3,292 m deep, were found in the back-arc region! These giant stacks are called black smokers and the maximum temperature taken at these vents was 339°C!! The most amazing part is that these vents were teaming with endemic wildlife that are found no where else in on the planet!
With the ROV, the crew also caught some amazing footage of lava pillows, which is where lava came up from under the Earth’s crust and was super cooled in the 2°C water leaving behind some fantastic geological formations. Some of which caused a lively debate between scientists all over the world about why and how the finger-like projections, seen here, formed.
Hydro-thermal vent called a black-smoker, found on the Mariana back arc. It is crawling with shrimp, crabs, snails, and scaleworms. Image courtesy of NOAA Office of Ocean Exploration and Research, 2016 Deepwater Exploration of the Marianas.
Everything comes from above!
Excluding the hydro-thermal vents that are essentially their own ecosystems with their own team of creatures, the rest of the deep ocean relies on nutrients/food that filter down from above.
For instance a dead whale carcass that eventually sinks to the bottom of the ocean will feed fish, crustaceans, worms, echinoderms, and many more living things for a hundred years! Even the filter feeding sponges, anemones, and corals get their food from particles of nutrients that eventually fall from above.
Sometimes it is the lack of resources from above, like sunlight, that drives the evolution of creatures. Down at about 500m only blue light can be seen, but below 1,000 m even blue light can’t reach. Fish found at these depth generally lack the bright colours that fish in shallow seas use for communication, defense or mate attraction. Down in the depths of the ocean below 4,000 m, called the hadal zone, a fish’s eyes are not as light sensitive, nor do they waste energy making pigments for colouration when no one can see it anyways. What you will get in the deep ocean are creatures using bioluminescence, which is a glowing light created by bacteria living within the animal’s tissues. This light can be used to attract prey or mates, and even serve as a distraction to get away or confuse predators.
Something else that the crew has seen in the deepest corners of the ocean is unfortunately something we have much of at the surface…garbage! Yup, even trash makes its way thousands of kilometres to the sea floor. The sad sight of beer cans and plastic bags were not as uncommon as you’d think. The images serve as a good reminder to all that the impacts we have here on the surface can affect ecosystems many kilometres away.
A can of spam on the sea floor. Image courtesy of NOAA Office of Ocean Exploration and Research, 2016 Deepwater Exploration of the Marianas.
What’s next?
The next leg of the Okeanos Explorer adventure has now begun. The ship will continue its journey further to the north in the Mariana region, mapping and sampling. If you’ve missed the link to the live video feed above…here it is again. Check it out and discover the world’s deepest point along with the crew and scientists all over the world. Who knows what they’ll see on their next dive!
