Bizarre Deep-Sea Hot Spots Shimmer

Shimmering hot methane pools this is awesome! I love the new term hydrothermal seep! At first it seems counterintuitive. Hydrothermal implies heated fluids. But seeps on the seafloor are usually cold, known to exist in the Gulf of Mexico, for example, due to changes in salinity. Something here at Jaco Scar off the Pacific coast of Costa Rica is different.

Cold seeps are essentially pools of methane-rich lakes on the ocean floor. Highly-saline methane and other hydrocarbon-rich fluids seep through the crust and pool on the seafloor. But add a volcanic seamount to the geologic mix, and now that same fluid gets heated as it moves through the crust.

The percolating hot fluids cool quickly once mixed with the freezing ocean waters, and it is the chemicals raining down from that mixture that build chimney formations -- those classic ebony/ivory hydrothermal vent smokers, some black (hot) and some white (warm) for example.

But in some places, these chemicals filter out more gradually and don't build up and sometimes few, if any, chimneys can be found in a hydrothermal vent setting. In such a situation, however, you can bet on seeing a shimmer in the water column, just as you would see driving along on a hot road in the desert.

"The site had been visited by other researchers using remotely operated vehicles," said lead author Lisa Levin of the Scripps Institution of Oceanography in La Jolla, Calif. in a statement. "But it wasn't until human eyes saw shimmering water flowing under a tubeworm 'bush' that we really understood how special Jaco Scar is."

Until then, the seamount was a known methane seep, but not considered hydrothermally active. Levin and her colleagues announced their findings today in the journal Proceedings of the Royal Society B: Biological Sciences.

I had a chance to see just such shimmering during a dive on the volcanic seamount Menez Gwen in the Azores with the Mir submersibles in 2003. The sediments on the seamount were such that as we pushed down with the manipulator arm to pick up a rock, a jet of hot fluid erupted nearby.

Bacteria, archea, and other organisms thrive on these marine geofluid chemicals whether they be hot or cold, but the temperature of the fluid here at Jaco Scar is key, as that is what determines what gets mixed into the solution when the fluid is traveling through the crust and -- consequently -- what falls out of solution once it reaches the seafloor sediments and mixes with ocean water.

Different organisms take advantage of different chemicals. At Jaco Scar, hydrothermal vent ogranisms are living next to cold seep organisms.

Read more at Discovery News