Tag Archives: biology

Living Fossil: Tiny mollusc makes big impression on marine biology world

Cover image:  Live monoplacophoran sighted during a remotely operated vehicle (ROV) dive on Utu Seamount in the waters of the American Samoa, February 2017. Image courtesy of NOAA Office of Exploration and Research.

A February 2017 dive by the NOAA Ship Okeanos Explorer yielded an exciting discovery. Scientists spotted a live monoplacophoran, a rarely observed type of mollusc that is thought to be the closest living relative of the ancestors of modern day bivalves (e.g. clams and mussels) and gastropods (e.g. snails).

For years, monoplacophorans were known only as fossils. Traces of their shells have been found in rocks from the earliest years of the Paleozoic era – 345 million years ago. This changed on May 6, 1952, when a Danish deep-sea trawling research expedition off the coast of Costa Rica unexpectedly hauled up ten living specimens from a depth of 3590 meters, each only about 3 cm long. This sudden discovery of an organism long thought to have been extinct was a shock, and scientists hailed it as “the most dramatic [discovery] in the history of [mollusc science].”

Monoplacophoran fossil. Image courtesy of the Museum of Comparative Zoology and Harvard University.

Since this initial discovery in 1952, a handful of other current-day monoplacophoran specimens have been discovered and at least 5 species have been described. A live specimen remains an extremely rare sight. These small, single-shelled animals inhabit deep ocean environments, which means that their habitats are difficult to access. Live specimens have been collected at depths ranging from 2000 meters to more than 6000 meters. Interestingly, some monoplacophoran fossils are associated with relatively shallow environments, which suggests that they may have more recently evolved to live in the deep ocean.

Anatomy of a typical monoplacophoran. They are “limpet-like” with a single shell. They underside of the animal would not have been preserved through the fossilization process, so obtaining live specimens allows scientists to investigate and analyze these otherwise unknown internal features. Monoplacophoran anatomy image courtesy of Ivy Livingstone, © BIODIDAC.

Studying live monoplacophorans has given scientists new insight on the development of major invertebrate groups. The discovery of live specimens of an animal previously thought to be extinct allows scientist to make observations beyond what can be preserved through the fossil record. The rarity of this organism, along with the story of its rediscovery and evolutionary significance, made its recent sighting a highlight of both the ROV dive and the February 2017 cruise as a whole.

Discovering the Deep: Exploring Remote Pacific MPAs

On March 25th, the NOAA Ship Okeanos Explorer wrapped up an exciting cruise to explore the depths of remote Pacific Marine Protected Areas (MPAs). As scientists collected data and made discoveries over the course of the expedition’s 19 dives, the remotely operated vehicles collected amazing images of life in the deep ocean. Continue reading Discovering the Deep: Exploring Remote Pacific MPAs

Amazing aphyonid fish!

The NOAA Ship Okeanos Explorer has been having an amazing cruise leg with lots of new discoveries. Last night the scientists made another amazing discovery. The scientists observed an aphyonid fish, roughly 10 cm long. This is the first time that this creature has ever been seen alive! 

Aphynoid fish. Never seen alive until today! Image curteousy of NOAA Okeanos Explorer.
Aphynoid fish. Never seen alive until today! Images courtesy NOAA Okeanos Explorer.

Scientists were thrilled to see such an amazing fish! This eel-like fish has been found around 2,000-6,000 meters. The aphynoid fish had transparent skin and reduced eyes. They are known for their unusual reproductive habits.

Be sure to follow the NOAA Ship Okeanos Explorer for more amazing discoveries!

Deep Discoveries Are Getting Seirios

How little is known about our ocean is a fact many agree on, however scientists are actively working to bridge the gap between the unknown and discovery. Right now, the National Oceanic and Atmospheric Administration’s Office of Exploration and Research (NOAA OER) began the third cruise of their current research expedition. Aboard the NOAA ship Okeanos Explorer with remotely operated vehicles (ROVs) Deep Discoverer and Seirios, scientists are well on their way to meeting their goals for this trip. The area undergoing daily exploration is the Commonwealth of the Northern Mariana Islands (CNMI) and the Marianas Trench National Monument (MTMNM) in the western Pacific. The latter area is under NOAA’s protection, based on inferences that there may be unique features within its depths. Gathering baseline data and learning more about what these areas contain will enable effective conservation initiatives.

Continue reading Deep Discoveries Are Getting Seirios

Sea Star of the Show

Scientists on the NOAA Ship Okeanos Explorer were thrilled to see a species of sea star alive for the first time in history. The six-rayed sea star,  Rhipidaster (confirmed over phone by Chris Mah from the Smithsonian Museum of Natural History), was found at Supply Reef,  an active submarine volcano within the Marianas Trench Marine National Monument.  The sea star was last catalogued by scientists over 150 years ago in 1860, when a dead specimen was found. Now, not one, but three of these remarkable sea stars were seen during a June 23, 2016, ROV dive, implying that the species has been living all this time. The fact that this species was seen in an unexpectedly biodiverse region speaks volumes of what else may be awaiting discovery beneath our oceans’ depths. The ship’s mission is far from over.  Participating scientists are excited to see what other unexpected discoveries remain to be revealed!

Okeanos Explorer cruise summary – Exploring the Marianas

The EX1605L1 leg of NOAA Ship Okeanos Explorer‘s trip to the Marianas was captivating, to say the least! From new species of jellyfish, to hydrothermal vent chimneys, this exploration leg was jam-packed with discoveries.

Okeanos started this cruise leg near Guam, then moved towards the Marianas Trench Marine National Monument (MTMNM) and the Commonwealth of the Northern Mariana Islands (CNMI). The Marianas Trench is known as the deepest part of the ocean, at almost 11,000 meters deep! The intention behind this cruise leg was to gather baseline knowledge of the biodiversity and geology of the area. The NOAA team onboard used their remotely operated vehicle (ROV) Deep Discoverer, “D2” to explore the area.

As always, the Inner Space Center at URI published those streams in real-time to YouTube and scientists worldwide. Some dives attracted as many as 2,500 simultaneous viewers.

The biology encountered in the Marianas was phenomenal! The cruise leg started off with a six-gill shark sighting at Santa Rosa Reef.

We discovered a wide variety of creatures inhabiting the area:

One of the most enthralling discoveries was a new species of jellyfish! This hydromedusa was found at Enigma Seamount at roughly 3,700 meters:

The Okeanos Explorer also made some great geological discoveries. They explored a newly-discovered hydrothermal vent site boasting one of the highest temperatures recorded in the Marianas region: 339 degrees Celsius. (Most of the deep sea is a chilly 2 degrees Celsius.) The 30-meter chimney base was releasing black “smoke” made up of iron and anhydrite precipitate.

Actively venting hydrothermal vent chimney shrouded in black smoke, and covered with vent animals, including shrimp, crabs, snails, and scaleworms. Image courtesy of NOAA Office of Ocean Exploration and Research, 2016 Deepwater Exploration of the Marianas.

There were also young lava flows that had created glassy pillow mounds. The area was so new that no animals had yet colonized the area.

That’s a wrap for Leg 1! Come back for more deepwater exploration on June 17th!

For more details about individual dives visit the NOAA Okeanos Explorer website.

Videos and images courtesy of the NOAA Office of Ocean Exploration and Research, 2016 Deepwater Exploration of the Marianas.

Sea Life and Salt

The NOAA science team stumbles upon an underwater salt lake, also known as a “brine pool.”

The NOAA Ship Okeanos Explorer has been diving its ROV, D2, in the Gulf of Mexico this April. Here is a video clip of one of their awesome encounters in the depths of the Gulf. A brine pool is literally an undersea lake. The contact between salty ocean water and much saltier water (brine), means denser water liquid separates from the less dense ocean water. This saltier fluid sits and “pools” on the bottom. It’s so salty that it will erode the sediment it lies on, forming these pools. If any deep sea dwellers happen to stumble into this pool, they have no chance of getting out (and definitely no lifeguards to help!). It’s a geological anomaly for sure, but it’s a nightmare for any biology living in this normally pitch-black environment. However, those creatures that can acquire some “waterfront” property, while anchoring themselves safely, may reap some serious benefits.

Click play below to listen and learn about these eerily beautiful formations, and the creatures surviving on their deadly coastlines.