The mysterious depths of the midwaterthe largest habitat on Earthextend from several
hundred feet below the ocean surface to just above the seafloor. The animals who live there
have adapted to weightlessness, almost total darkness and infrequent meals. Because there’s
almost no turbulence in the deep ocean, some animals, like jellies, have developed
balloon-like, diaphanous bodies that are extremely fragile.
The calm of the midwater has led to unique hunting styles as well. While some animals,
like squid, are active predators, many midwater fishes and jellies simply drift in the
darkness, waiting for their prey to drift or swim by.
On this mission you can send a remote-controlled sub into the midwater to photograph
bizarre deep-sea creatures, such as vampire squid, giant deep-sea jellies and spookfish.
More than three quarters of the animals in the deep sea can produce their own light through bioluminescence.
Many deep midwater animals are red in color. This makes them almost invisible in the dim blue light that filters down from the sea surface.
When attacked, some jellies light up like burglar alarms to make their attackers visible to even larger predators.
Some midwater fishes and jellies have transparent bodies but their stomachs are opaque. This way, when they eat a glowing animal, they don’t become visible to other midwater predators.
Almost every time MBARI midwater researchers make ROV dives more than a mile below the surface, they see animals that have yet to be given scientific names.
When MBARI scientists want to capture a fragile jelly for study in the
lab, they use a remotely operated vehicle equipped with a
“detritus sampler”essentially a clear plastic cylinder with swiveling
lids on its top and bottom. To capture an animal, the ROV pilots must
“fly” the massive ROV so that the sampler slides down over the animal.
Then they close the lids, trapping the animal inside.
VIEW ANOTHER MISSION
Craig Dawe is the chief pilot for MBARI’s remotely operated vehicle (ROV) Ventana.
Here he describes what it’s like to pilot a midwater dive from an ROV.