#seamount

An underwater photo of the "seabed gardens" on a Mariana Trench seamount, taken by Chinese scientists on the research vessel KEXUE on May 28, 2019.

Word of the week. Palabra de la semana.  

With only one-quarter of the sea floor mapped with sonar, it is impossible to know how many seamounts exist.

Is it the ocean or outer space? This cosmic jellyfish combines the best of both worlds!

Researchers on the NOAA Ship Okeanos Explorer found this spectacular little jelly with a remotely operated vehicle while exploring the Utu Seamount in National Marine Sanctuary of American Samoa.

More uses for gravity

Our last post talked about using changes in Earth’s gravity field to measure groundwater, but the satellite used for that measurement isn’t the only one taking advantage of the Earth’s gravitational field. The European Space Agency’s Cryosat-2 Satellite and a combined NASA/French Jason-1 satellite both orbited the Earth, producing measurements of the gravity field. Cryosat-2 was designed to study the changes in gravity over the polar ice caps as they melt, Jason-1 was built to measure changes in sea level. Together, they also produced maps of the gravity field around the world that can be used for interesting applications.

This photo is a recent map of the world’s ocean floor containing literally tens of thousands of new mountains. They’re underwater, known as seamounts, so they can’t be seen at the surface; only spotted in gravity. A small mountain on the ocean floor will distort the gravity field enough to change sea level, allowing both Jason and Cryosat-2 to measure it. The red dots in this map mark earthquake locations just to make sure the mid-ocean ridges and faults are well located.

In addition to mapping out seamounts, this type of data will also be useful for peering through sediments, giving both scientists and industry a chance to better-constrain the types of sedimentary deposits offshore that are being accessed for energy and other resources.

-JBB

Image credit: David Sandwell, Scripps Institution of Oceanography

Today is International Mountain Day – and did you know that there are mountains in the ocean? 

Seamounts are undersea mountains formed by volcanic activity, and they're typically biological hotspots. For example, on Davidson Seamount in Monterey Bay National Marine Sanctuary, researchers with Nautilus Live encountered more than a thousand Muusoctopus octopuses tucked into nooks! Most of the octopuses had their arms inverted in a brooding posture. 

We love a good octopus garden, but we love an octopus garden on an ocean mountain even more! 

(Photos & GIFs: OET/NOAA)