[Ernest_at_the_Beach]

Found this:

Phytoplankton and Benthic Algae

So is it Benthic Algae you are referring to?

Found this from researchers at South Florida:

The Role of Phytoplankton in Benthic-Pelagic Coupling

The quote from the CNN article that started this thread:

"The dispersant is moving the oil down out of the surface and into the deeper waters, where it can affect phytoplankton and other marine life," said John Paul, a marine microbiologist at USF.

[Carry_Okie]

Gad Ernest, we're talking stuff I learned 25 years ago in an oceanology course!

The is about the DeSoto Canyon, which is off the coast of Pensacola, FL. From what I could find in a quick scan it goes to a maximum depth of about 3,000 feet, which is at the lower limit of the mesopelagic zone. Some light does penetrate this deep and there are phytoplankton that live in the mesopelagic zone, but I do not know how deep.