Summit County Citizens Voice

A NOAA map shows sites where research ships monitored underwater plumes of oil in the Gulf of Mexico.

NOAA researchers say dissolved oxygen levels not at dangerously low levels yet, but also report concerns with accuracy of readings

By Bob Berwyn

SUMMIT COUNTY — Federal researchers last week confirmed the existence of multiple plumes of deep sea oil in the Gulf of Mexico. Some of the plumes are now as far as 20 miles from the failed BP well that spewed millions of gallons of oil into the water before it was capped.

The underwater oil clouds, formed by the extensive use of dispersants used to break up the oil, are drifting to the south and west with prevailing currents between 3,300 and 4,300 feet below the surface, the National Oceanic and Atmospheric Administration said after evaluating the data retrieved by five research ships.

The ships gathered data at 227 sampling stations extending from one to 52 kilometers from the Deepwater Horizon/BP wellhead. The amount of oil collected from the shorelines and the surface of the water doesn’t com close to matching the total amount that spewed from the well. The rest of the oil is floating around under the surface, with uncertain consequences for marine life in the Gulf.

The federal researchers used fluorometric sampling to detect anomalies in the water column. Researchers deployed water sampling devices in areas where the anomalies were detected to collect samples which are undergoing chemical analysis in the labs to determine the actual levels of hydrocarbons present.

University of South Florida researchers said the concentrations of dispersed oil in most cases are just below levels considered toxic to humans. Other concerns include the oil being absorbed by small fish and even plankton at the base of the food chain, where it eventually could contaminate bigger fish and other sea creatures.

Water sampling also showed a drop in dissolved oxygen levels in the same areas where the oil was detected. The NOAA scientists said those decreases may be related to a breakdown of oil by oxygen-consuming microbes. According to the federal data, the drops were not severe enough to indicate impending hypoxic conditions.

But in its statement, NOAA said there is some concern that the instruments used to monitor oil may be affected by that oil in the water. Future sampling efforts will include the use of a second dissolved oxygen testing system that provides definitive readings at specific locations.

While the feds say there is no immediate threat of widespread oxygen starved areas that could wipe out sea life, other university researchers are also conducting tests to try and verify those results. Some scientists say it’s only a matter of time before the microbes use up most of the oxygen, which could lead to huge dead zones in the Gulf.

Methane gas trapped deep in the ocean is another concern, according to this story just published by Mother Jones.

While BP and the feds are trying to emphasize the positive by pointing at their success in cleaning up visible oil along beaches, there is no good plan for removing the millions of gallons of diluted oil that is floating below the surface of the sea.
The hope is that microbes in the water will break down the oil and render it harmless, but some scientists said the combination of oil and oil-based dispersants could be toxic to the very bacteria that are supposed to do the job.

Filed under: BP Gulf oil spill, Environment, Summit County Colorado Tagged: | BP, Environment, Gulf oil spill, oil spill cleanup plan, Summit County News, underwater oil plumes