Even Small Amounts of Oil and Dispersant Are Toxic to Phytoplankton ... the Basis of the Entire Gulf Food Chain → Washingtons Blog
Even Small Amounts of Oil and Dispersant Are Toxic to Phytoplankton ... the Basis of the Entire Gulf Food Chain - Washingtons Blog

Wednesday, January 19, 2011

Even Small Amounts of Oil and Dispersant Are Toxic to Phytoplankton ... the Basis of the Entire Gulf Food Chain

Naomi Klein said at her December 8th TED talk:

What [scientists] found is that water with even trace amounts of oil and dispersants can be highly toxic to phytoplankton—which is a serious problem because so much life depends on it. So contrary to those reports we heard back in August about how 75 per cent of the oil has sort of disappeared, this disaster is still unfolding, still working its way up the food chain.

She's right.

As The Ecologist noted last September:

This process of dispersing oil neither eliminates nor decreases its toxicity. In fact it creates a much more toxic cocktail of oil and chemical dispersant. Experts say this cocktail mix is now beginning a slow but sure degradation of the ecosystem from the bottom up. Despite this environmental officials in the US have allowed them to be used on an unprecedented scale.

Tiny droplets of combined oil and dispersant adhere to plankton, says Dr Susan Shaw, founder and director of the Marine Environmental Research Institute (MERI). The plankton-eaters then indiscriminately gobble up the tainted particles while fish-eaters consume the poisoned plankton eaters, and so on through the marine food web.
The Tampa Tribune wrote in September:

Most of the oil and dispersant are still below the surface and have the potential to cause long-term damage the eco-system, according to University of South Florida researcher John Paul who is included in a documentary debuting Tuesday night in the National Geographic Channel.


They discovered plumes of dispersed oil at the bottom of an undersea canyon about 40 miles off the Florida Panhandle.

It was found to be toxic to microscopic sea organisms, causing mutations to their DNA.

If this plankton at the base of the marine food chain is contaminated, it could affect the whole ecosystem of the Gulf.


"The problem with mutant DNA is that it can be passed on and we don't how this will affect fish or other marine life," he says, adding that the effects could last for decades.

National Geographic reported in October:

Even in the turbulent, highly oxygenated waters of France's Breton coast, it took at least seven years after the 1978 Amoco Cadiz spill for local marine species and Brittany's famed oyster farms to fully recover, according to French biologist Philippe Bodin. An expert on marine copepods, Bodin studied the long-term effects of the spill from the grounded tanker. He believes the impact will be far worse in the generally calmer, lower-oxygen waters of the Gulf, particularly because of the heavy use of the dispersant Corexit 9500. BP has said the chemical is no more toxic than dish-washing liquid, but it was used extensively on the Amoco Cadiz spill, and Bodin found it to be more toxic to marine life than the oil itself. "The massive use of Corexit 9500 in the Gulf is catastrophic for the phytoplankton, zooplankton, and larvae," he says. "Moreover, currents will drive the dispersant and the oil plumes everywhere in the Gulf."

AP noted in November:

Scientists say they have for the first time tracked how certain nontoxic elements of oil from the BP spill quickly became dinner for plankton, entering the food web in the Gulf of Mexico.


"Everybody is making a huge deal of where did the oil go," said chief study author William "Monty" Graham, a plankton expert at the Dauphin Island Sea Lab in Alabama. "It just became food."


Michael Crosby of the Mote Marine Laboratory in Florida didn't take part in the study but said what fascinated him was that the carbon zipped through the food web faster than scientists expected. That in itself isn't alarming, but if the nontoxic part of the oil is moving so rapidly through the food web, Crosby asks: "What has happened to the toxic compounds of the released oil?"


Graham's study, released Monday, is published in Environmental Research Letters. It was mostly funded by the National Science Foundation, with additional money from the state of Alabama and BP's Gulf Research Initiative, which distributed money through the Northern Gulf Institute in Mississippi.

And as the Herald Tribune wrote in November:

For birds, fish, sea turtles, marine mammals and ocean-based economies on the Gulf coast, the immediate catastrophe from the BP Deepwater Horizon oil spill has ebbed, but the long-term effects have yet to unfold.

Everything, from shrimp fleets in Louisiana to chicken wings in Buffalo, hinges on the health of tiny plants and animals at risk from oil lingering in the environment. Undetectable by sight or smell, trace amounts of degraded oil are poisoning these species, called plankton, at the bottom of the food chain, scientists say.


"When you are perturbing the food web from its foundation, the ultimate ecological response could be catastrophic," said David Hollander, a chemical oceanographer with the University of South Florida's College of Marine Science.

Hollander and his colleagues at USF are among the first to suggest that plumes containing extremely low concentrations of BP oil are having toxic effects on beneficial algae, a large component of plankton.


These animals, including shrimp, menhaden, oysters and clams, spend a part of their lives as zooplankton, tiny larvae that float at the whim of ocean currents and gobble other bits of plankton.

The spill coincided with the time of year when those zooplankton drift near the surface of the deep sea. They likely encountered oil and chemical dispersants used to dissolve the oil. If direct exposure did not kill them, they could still suffer reduced immunity to disease or genetic mutations that interfere with their growth into reproductive adults.

Scientists know oil and dispersants are toxic to plankton, so they theorize that diminished food would also take a toll on larval critters that do not get exposed to oil.

They would either starve or not get enough nourishment to reproduce.

"It's a whole cascading thing of possibilities that end up being a decline in reproductive output," Condrey said.

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