‘Enormous’ environmental costs of BP Gulf spill

Professor Rick Steiner is a marine conservation biologist based in Anchorage, Alaska. A veteran of the Exxon Valdez disaster, he has been advising in the Gulf of Mexico following the BP oil spill.

Despite what some oil company executives would have us believe, oil, water, fish, and wildlife actually don’t mix.

BP CEO Tony Hayward’s statement (in May 2010) that the environmental damage from the Deepwater Horizon disaster will be “very, very modest” is simply one of the most arrogant, ignorant, callous statements I have ever heard from any corporate chief executive during a crisis such as this.

The environmental damage from the Gulf spill has already been, and will continue to be, enormous. Whenever thousands of tons of toxic hydrocarbons are spilled into a productive coastal and marine ecosystem, the damage will unavoidably be serious.

The State of Louisiana lists some 600 species at risk from this spill – 445 species of fish, 45 mammals, 32 reptiles and amphibians, and 134 bird species.

And as this spill is so unique, with so much oil coming into the sea at 5,000 feet deep and 50 miles from shore, the impacts will be very different than in most other surface spills with which people are more familiar.

BP oil spill: environmental impact

The environmental damage is occurring in four ecosystems – the offshore waters, inshore coastal waters, the seabed, and shoreline wetlands and beaches.

Here is the body count for the large animals as of day 60 (18 June)

Birds – total collected 1550, of which 885 dead 
Sea turtles – total collected 469, dead 363 
Marine mammals (mostly bottlenose dolphins) total collected 47, dead 44.

And this is only the count of the ones that have been collected. 

Research on other relatively deepwater oil releases has shown that they behave in a very different, more complicated, manner than shallow water blowouts.

In the deepwater blowouts, the lighter oil tends to quickly phase-separate, some dissolves into surrounding seawater, the gas forms methane hydrates and precipitates to the seabed, and the lighter components emulsify with seawater and rise to the sea surface to form the surface slicks we are seeing in the Gulf of Mexico.

But the heavier components of the oil (asphaltines etc) from deepwater blowouts have been found to rise to a “terminal depth” at which point they lose buoyancy (called the neutral buoyancy level) and then hover in the water column.

With this understanding, it is probable that a significant amount of the oil from the Deepwater Horizon blowout has yet to surface, and remains entrained at depth, drifting with deepwater and midwater currents beneath the ocean surface.

One of the only research vessels that has studied the Deepwater Horizon blowout – the R/V Pelican – detected evidence of these deepwater plumes trending southwest from the blowout. But so far, the federal government has conducted little biological monitoring of the impacts of the spill on the offshore pelagic ecosystem.

The subsurface plumes likely remain toxic longer than at oil at the surface, as the water is colder than at the surface (40 degrees), and there is no sunlight to aid photo oxidation. And if the application of dispersant at the blowout site is working as planned, there is far more subsurface oil in the water column, and less on the surface.

Toxic double-whammy
The chemical dispersants used on the surface and at the blowout are a particular concern, Rick Steiner explains. Never has there been such heavy use of chemical dispersant in any oil spill response.

The product used – Corexit 9500 – is intended to break oil into smaller droplets in order to speed natural breakdown into harmless substances.
The problem is that the dispersant is itself toxic, the oil is even more toxic, and research has shown that the combination of the oil and dispersant is even more toxic than the sum of the individual toxicities alone – there is a synergistic toxicity.

Offshore impact
What all this means is that the impacts from the Deepwater Horizon spill will largely be offshore, in the pelagic (or water column) ecosystem. There has already been significant contamination of shorelines and fragile marshes, but the greater damage will be offshore, in the water, and out of sight of traditional observations.

It is perhaps a conventional chauvinism of terrestrial primates (homo sapiens) to be more concerned about impacts we see on or near shore, but the greatest impact from this spill will almost certainly be offshore.
This includes damage to what are known as “charismatic mega fauna” – dolphins, whales, sea birds, sea turtles, and so on. But significantly, the damage from this spill will be felt in an ecosystem that to most people is out of sight, out of mind.

This damage has without doubt already been enormous. The Gulf of Mexico is a critical spawning habitat for many large fish species – blue fin tuna, blue marlin, white marlin, and sailfish.

The eggs and larvae from these important fish species are floating in the upper water column of the north Gulf right now, and a significant amount of these larvae have undoubtedly been exposed to the toxic underwater cloud of oil and dispersant. These larvae are known to be highly vulnerable to such hydrocarbon toxicity, and even the lightest exposure can cause death.

Short of acute mortality, these fish eggs and larvae can also suffer sub-lethal, chronic injury such as respiratory, cardiovascular, nerve, organ tissue, and genetic damage that may not kill for months or years into the future.

It is without question that the oil spill has caused a significant impact to these fish populations. Further, the entire pelagic zooplankton community is at risk of significant exposure and injury from the spill as well.

BP statement on dispersants
A spokesman for BP said in May: "The investigations have not been completed, and we won't prejudge them. However, here's a note on our initial findings.
"The EPA asked us to evaluate other approved dispersants for effectiveness and availability. (Corexit is an EPA approved dispersant). This we did, and Corexit was the only one which met both requirements. We continue to evaluate other dispersants and supplies.
"The subsea injection of dispersants which received the regulators' approvals is more effective than surface spraying and requires less dispersants for each treated barrels. Both subsea and surface treatment continue. 
"In the meantime, and for longer term, we have announced a $500m research programme."

Seabeds at risk
In the deepwater Gulf of Mexico, there are two precious seabed habitats that are at considerable risk of oil-injury as well: deepwater coral reefs and the remarkable chemosynthetic cold-seep ecosystems.

There are many deepwater (cold water) coral systems across the continental shelf of the Gulf, including the well-known “pinnacles” reefs at 300-500m deep, stretching some 60 miles along the shelf edge just 25 miles inshore of the blowout.

And the strange seabed ecosystems that surround natural deepwater methane seeps in the Gulf are vulnerable as well. Organisms in these cold-seep systems derive their energy directly from the methane – chemosynthesis – rather than normal plant-derived energy from sunlight in surface ecosystems – photosynthesis. The cold seep systems host a variety of species new to science, and that are endemic to these isolated habitats.

The inshore and shoreline impacts of the spill will be huge as well. As the oil/dispersant mixture is scattered down throughout the water column inshore, the critical inshore habitat for the two most important commercial fisheries in the area – menhaden and shrimp – has suffered significant contamination.

Has the oil really 'gone'?
In August, the BP oil leak crisis appeared to be entering a new chapter with the "static kill" stemming the flow of oil. Professor Steiner analysed the latst phase for Channel 4 News:

"The spilled oil fraction defined as 'dispersed' is generally misunderstood to be ‘gone’ from the environment, but even the report does not claim this. 

"The (US government's estimated fate of the spilled oil) defines 'dispersed' oil simply as oil droplets smaller than 100 microns (1/10 mm) diameter, but does not claim that this oil has degraded. It is dispersed and hopefully degrading, but certainly not entirely gone. 

"If one adds the dispersed estimate (24 per cent) to the residual fraction (26 per cent), the report concludes that half of the spilled oil could still be in the ecosystem."
Read more here: BP oil spill response did not work

Oil in the marshes has already begun to kill coastal vegetation that stabilises the ever-shifting sediment substrate, thus making coastal wetlands more vulnerable to erosion. And when the first hurricane sweeps through the coastal area this summer, any oil on the surface, in the water, or in the near shore sediment will be re-suspended and flow with the storm surge into wetlands that had not been previously contaminated.

We know from other oil spills that the environmental damage can be long lasting, and some of it may not be evident for years to come. The ecological injury from the 1989 Exxon Valdez oil spill in Alaska is today still evident. Twenty-one years later, two-thirds of the fish and wildlife populations injured by the spill have yet to fully recover, some are not recovering at all, and thousands of gallons of toxic oil remain in Alaska beaches.

A warmer environment as in the Gulf will certainly aid the natural degradation of the oil there, but the environmental damage may still last for years to come.

In addition to the environmental damage from the Deepwater Horizon spill, there has been and will continue to be extraordinary social and economic damage. Human communities may turn corrosive, with higher indices of substance abuse, domestic abuse, and emotional distress. And the economic injury due to closure of fisheries and tourism businesses will be huge as well.

Rick Steiner's list for the Gulf restoration plan:
1. Let the river run – restore the periodic flood flow of the Mississippi river.
2. Eliminate the dead zone - reduce the input of nutrients down the river.
3. Reduce coastal degradation – better manage, reduce, or eliminate the amount of coastal channelization, wetlands loss, road building, etc.
4. Halt overfishing
5. Establish additional protected areas - both marine and coastal.
6. Build artificial seabird nesting islands in inshore areas - as the coastal nesting islands have dramatically eroded over the past several decades.
7. Prevent other oil spills – if the Gulf can recover from one Deepwater Horizon disaster, and that is a big if, it almost certainly can’t from another on top of this one. 
Read more here: http://www.channel4.com/news/article.jsp?id=3690177&time=150825