The Finale of the Okeanos Explorer: The Mariana Trench Expedition Part 3.
The Okeanos Explorer has finally finished its first journey. This expedition started April 20th, 2016 and finally ended on July 10th, 2016, a total of 81 days! It has definitely been a successful venture and will surely go out on other similar scientific expeditions (actually its next expedition, Deepwater Wonders of Wake, began on July 27th). But for now let’s re-cap the last leg of this amazing journey.
The first few dives
SHAAAAAAARK! Yes, sharks in the deep sea! On the third dive, the team encountered a smalltooth sand tiger shark, at a length of about 1.5 metres, and it looked like she was pregnant! This is super cool as deep sea creatures, sharks included, tend to mature later in life and have fewer young. This species of shark also gives birth to live young. She will eventually give birth to 1 or 2 baby sharks, called pups, that are almost 1 metre long. To see a video of the sand tiger shark click here!
SUUUUURRRRRPRISE! We have no clue what one some of the findings are! You might think that with the strong telepresence the Okeanos has on-board, that within the hundreds of scientists tuning in to watch, someone would have the answers…well that’s not always the case. A few times the Remotely Operated Vehicle (ROV) pilots came across something that we just couldn’t identify—which is OK! If scientists knew everything, then what would be purpose of expeditions like this?
Some of the unknown specimens found by the Okeanos Explorer: “Strange little spheres”, “spherical white things” and “green stringy thing”. Images courtesy of NOAA Office of Ocean Exploration and Research, 2016 Deepwater Exploration of the Marianas.
This dense sulfur plume was probably coming from a pool of molten sulfur on the seafloor. Image courtesy of NOAA Office of Ocean Exploration and Research, 2016 Deepwater Exploration of the Marianas.
Diving on Seamounts
During dives 5, 8 and 9 the Okeanos Explorer crew explored three active submarine volcanoes: the Ahyi, Eifuku, and Daikoku seamounts. Ahyi and Daikoko have both been recently active as of April-May and December of 2014, respectively. This was the teams chance to check out what has been going on since the eruptions…and the seamounts were exploding with life! To check out some of the videos of creatures seen on the seamounts, you can watch by clicking here. Despite the active sulfur plumes, the team came across a huge school of flatfish and some ash-covered tubeworms, to name a few inhabitants.
A look at the historic record of the Cretaceous seas when this seamount was near the surface shows fossil bivalves and gastropods. Image courtesy of NOAA Office of Ocean Exploration and Research, 2016 Deepwater Exploration of the Marianas.
Some seamounts show their age with pride. Guyots are seamounts that have a flat top due to age and erosion. One particular guyot sitting at about 5,000 metres deep had some beautiful fossils of bivalves (clam-like animals) and gastropods (snail-like animals). These likely dated back to the cretaceous period when this particular part of the Earth’s crust was much more shallow, instead of in the depths of the Mariana Trench.
An eel by any other name…
When thinking of deep sea fish, we often remember the anglerfish (like the one in Finding Nemo), and these do exist in the depth of the Mariana Trench, but more often than not, scientists find anguilliform fish. What is “anguilliform”? It is an “eel-like”-shaped fish, not necessarily an eel, that has an elongated, tapering body and swims with an undulating motion. Deep sea biologists believe that this body shape uses less energy to swim, which is important in a habitat that doesn’t provide much energy to begin with. The anguilliform body is also good for backing up and doing u-turns, however the fish loses a bit of maneuverability, which isn’t very necessary in their deep sea environment.
All fish have a lateral line, which is an actual line of specialized cells that are found along the length of the fish’s body. These cells sense vibrations and pressure waves, which is a useful way to find food where there is no light to see by in the deep. Anguilliform fish, have a longer lateral line system due to their elongated body shape and therefore may have an advantage for food or against predators.
Right: cutthroat eel, active at night. Left: cusk eel, found between 1,000-6,000. Images courtesy of NOAA Office of Ocean Exploration and Research, 2016 Deepwater Exploration of the Marianas.
My notes
Having been able to watch the Okeanos Explorer‘s adventures for the past couple of months has been very exciting for myself and other land-locked biologists. We tuned in here in the Lakes and Rivers Lab at Science North almost every day to see what the crew had found the night before. I got very excited at every starfish, fan coral and shrimp, not to mention the sharks and octopus! Here are some of the “screen shots” I took from my laptop screen as I tuned in from my desk.
My hat is off to you!
Let’s take a minute to think about what goes into planning these types of scientific expeditions. In order to make sure the data collected by the ship and its crew can be used by as many scientists as possible, many partnerships need to be forged. To balance all of the demands made by those scientists, many compromises and sacrifices are made so that everyone can get a piece of what they want. Think about the logistical constraints of weather, equipment and people that mean that the “plan” is constantly changing and evolving so that the expedition can’t fail. My hat is off to the crew on and off the ship for making all of this “cool science” a possibility and sharing it with us around the world! Good luck on the next adventure!
