Thousands of barrels of oil are leaking out of the Deepwater Horizon site each day. The oil ascends from depths of approximately 1502 m. (4928 ft.), but not all of it reaches the sea surface. The stratified seawater of the Gulf of Mexico captures or slows the ascent of the oil, and the addition of dispersants near the oil source produces tiny droplets that float for a considerable time in the water column and may never reach the surface.

Oil plume diagram.

According to Drs. Gregor Eberli, Mark Grasmueck, and Ph.D. candidate Thiago Correa of the Marine Geology & Geophysics division of the University of Miami (UM), the oil that remains in suspension in the water column and creates plumes poses a serious risk for the planktonic and benthic (sea floor) life throughout the region, including the deep-sea reefs they study.

“The deep water communities within the Gulf of Mexico and in the Straits of Florida are well hidden from us, but they include many species of cold-water corals that live in water at depths of 600 — 1500 m. (1969 -4921 ft.) in waters as cold as 3° Celsius (37.4°F),” said Eberli. “Unlike their more familiar shallow-water counterparts, these corals do not live in symbiosis with unicellular algae called zooxanthellae, but are animals that feed on organic matter floating through the water column. We know that most of the food consumed by the cold-water corals is produced in the surface waters and eventually sinks down to the corals.”

The large plumes being created by the oil spill, some of which are reported to be several miles long, sit in the water column situated between this source of food and these deep-water corals. As organic material sinks through the water column it passes through the oil plumes and is contaminated by micron-sized oil droplets.

“It is most likely that the delicate cold-water corals are not able to digest these oil-laden food particles and will perish in large numbers,” said Eberli. “We are especially concerned because the migrating oil plumes have the potential to destroy or greatly diminish these deep-sea coral communities as they are carried by the currents. These corals are important because they are the foundation of a diverse ecosystem that at last count includes over 1,300 marine species, according to Dr. Thomas Hourigan at NOAA.”

There is also a danger that these plumes are carried by the Loop Current from the Gulf of Mexico to the Atlantic Ocean. Deep-sea coral ecosystems are common at numerous sites from the eastern Gulf of Mexico through the Straits of Florida and northward to the Blake Plateau off North Carolina. This distribution matches the path of the Loop Current that forms from the water masses in the Gulf of Mexico, and enters the Straits of Florida to form the Florida Current and further north the Gulf Stream.

Particularly vulnerable to disturbance are deep-sea fish that form part of this ecosystem because of their late maturation, extreme longevity, low fecundity and slow growth. Deep-water coral reefs in Florida waters are the habitat of the economically valuable grouper, snapper and amberjack. These and other species inhabit hundreds of deep-water coral reefs off the coast of Florida at depths of about 300 -915 m. (1000 to 3000 feet), which were explored by Dr. John Reed from Harbor Branch Oceanographic Institute some thirty years ago. This includes the 59,500 sq. m. (~23,000 sq. mi.) of deep-water reefs off the east coast of Florida, which is now proposed as the Oculina Habitat Area of Particular Concern.

There is no known technique to clean the water column from these oil plumes, and as a consequence the hidden oases of corals in the deep, cold waters of the Gulf of Mexico, the Straits of Florida and the Blake Plateau are in severe danger of being decimated by this oil spill.

Undersea video coverage Thursday night showed engineers lowering a ‘top cap’ over a severed riser pipe at the bottom of the Gulf to contain BP oil spill. The company hopes to contain 90 percent of the geyser.

The plume of oil continuing to flow Friday morning at the bottom of the Gulf of Mexico signals that BP has not yet fully succeeded in sealing the source of the BP oil spill and siphoning the captured oil to a tanker on the surface – at least not yet.

BP engineers, with government scientists looking over their shoulders, on Wednesday cut a crumpled riser pipe left over from the sinking of the Deepwater Horizon rig on April 22. Subsea “disaster bots” failed to make a clean cut with a diamond-tipped saw on Thursday, jamming it instead into the pipe. After extracting the fine-cut saw, engineers opted for a pair of giant shears to lop the pipe. As bots later filmed the lowering of the “top cap” – a sort of giant garden hose seal – over the lower marine riser package at the top of the well, oil continued to spew from the scene.

More than 100 miles of marshland and beaches are already tarred, and a fishing area the size of Florida is closed in the Gulf.

IN PICTURES: Louisiana oil spill

In a press conference on Thursday, President Obama’s point man, Coast Guard Adm. Thad Allen, said the jagged shear cut could undermine the effectiveness of the “top cap,” because the seal may not be able to fit smoothly. That seemed to be the case early Friday morning, according to the BP “spillcam,” as a plume of oil and gas burst from the side of the top cap and a “dispersant ops” sub injected a kerosene dispersant into the plume via a long rod.

Allen is expected to update the situation Friday morning, perhaps giving an estimate of the current flow rate of the geyser and indicating whether BP has a plan to further restrict it as the operation moves forward.

Doug Suttles, BP’s chief operating officer, told the CBS “Early Show” that the company hopes to capture 90 percent of the escaping oil. “Of course what we have to do is work through the next 24 or 48 hours to optimize that,” Mr. Suttles said. “We want to stop this oil from spilling to the sea.”

BP has said its best chance to completely kill the well is to drill a relief well to intersect with the existing well, into which cement can be poured to cap the runaway well. Two such relief wells are already being drilled, but that work won’t be completed until August at the earliest, Christmas at the latest, scientists estimate.

The total amount of oil that has spewed from the well is now into the tens of millions of gallons, perhaps twice the amount that leaked when the Exxon Valdez hit ground in Prince William Sound in 1989. It’s by most accounts the worst environmental disaster in US history.

The leaking oil from the top cap is the latest in a string of “If it can go wrong, it will” events in the six-week effort to kill the Macondo well 5,000 feet below the Gulf. President Obama said Thursday on CNN”s “Larry King Live” that the accident happened “because someone didn’t think through the consequences of their actions.”