Few places on Earth are as unexplored as the deep sea.
The ocean floor is constantly in flux, sculpted by volcanic eruptions, altered by complex chemical processes, and colonised by rich biological communities.
For many years, the only way scientists could get a glimpse of these mysterious places was by going on occasional expeditions by ship and sending submersibles into the deep.
But not anymore.
The University of Washington, NSF-OOI, and Canadian Scientific Submersible Facility provided these images of the new observatory and the mysterious sights in these dark reaches of the ocean:
Before the ocean observatory was built, scientists could only study the seafloor using robotic vehicles like this one. But these expeditions were sporadic, and could only capture brief glimpses of the ocean floor.
But recently, scientists installed a sophisticated network of sensors along an underwater mountain range in a region northwest of Oregon and Washington known as the Juan de Fuca Plate. This 'ocean observatory' is connected to shore by fibre optic cables, as shown below:
One of the sites covered by the observatory is a volcano called Axial Seamount, located about 300 miles west of Oregon. Thanks to earthquake sensors on the seafloor, scientists were able to forecast its eruption in April 2015.
The 2015 eruption blanketed the seafloor in lava more than 400 feet thick! Here, you can see a large extrusion of lava, which appears bluish in artificial light. Sunlight can't penetrate to these depths.
As the more-than-2000°F lava came in contact with near-freezing seawater, the outer surface cooled rapidly or 'quenched,' giving it this glassy black appearance. After the eruption, the new, dark lava (bottom left) appeared on top of older, pale lava (top right). The older lava's colour is probably due to microbes living on it.
The last time Axial erupted was in 2011, when a region called Skadis Cauldron was spewing out huge amounts of microbes and fluid. It's still venting cloudy fluid three years later!
The volcanic seafloor is also home to diverse communities of organisms, such as these bacteria, which had formed a 'mat' over the new lava flow just three months after the 2015 eruption.
Cracks and vents in the seafloor provide a rich source of energy and nutrients for creatures like this pink sea anemone, which has made its home on a snail's egg casing in this image below:
...or this beautiful starfish, which is clinging to some rocks about 3,000 feet below the ocean's surface:
Sometimes, scientific equipment itself becomes home to enterprising sea creatures. A school of fish was delighted to find this float for a sensor that measures ocean currents and water properties.
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