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“Red Herrings” in the Gulf of Mexico – Part 2: Key Ocean Ecosystems at Risk

By / Bio / Published: September 14, 2010

This is the second post in a four part series discussing the ongoing – and “cascading” – effects in the Gulf, not from “oil,” but rather its toxic components and their impacts on sensitive ecosystems. Read the rest of the series.

I remain extremely concerned about what has happened to the out-of-sight, underwater ecosystems of the Gulf of Mexico, especially at middle depths and on the bottom. These little known but ecologically vital elements of the ocean have been heavily exposed to oil-based pollution, both rising from the bottom and sinking back down from the surface, and – at least in some places – bathed in persistent underwater toxic plumes.

Marine life in the mid-waters is so rich and profuse in places that sonar waves bounce back as a “deep scattering layer” and provides key food for many familiar, surface-diving animals, including whales, dolphins, billfishes and giant tunas. Deepwater coral reefs and other bottom dwellers have been at great risk all along, and not even the initial explorations have yet been done to assess the impacts of reefs less than twenty miles from the broken well bathing in oil-based pollution.

An actual track of a sperm whale diving through rich mid-water feeding zones (shown in green) from the northern Gulf of Mexico. Credit: Modified from Azzara, 2006.

The oil and oil-derived pollution that made it to the surface followed – and is following – one set of pathways through the Gulf ecosystem, exposing and injuring not just sea turtles and sea birds, but also near-surface marine animals and plants, large and small, and entering foodwebs through a complicated series of entry points, which we don’t yet fully understand.

Fine droplets of dispersed pollution are more likely to be adsorbed onto particulates, sinking back through the midwaters and into the abyss. The moreresistent elements, like tar balls, either float away or sink back into the abyss, and follow a different set of pathways.

The total “dump” of highly toxic oil components, including low-molecular weight aromatic hydrocarbons (known familiarly as “BTEX” – benzene, toluene, ethyl benzene and various xylenes), could have been up to 50,000,000 gallons. These are heavy-duty pollutants in their own right, including known carcinogens and reproductive toxicants, with a fair solubility in sea water. In a surface spill, pollution mostly evaporates, and the only real concern relates to emergency response workers that are exposed while on duty. In this underwater case, scientists simply do not know – yet – exactly how the massive load of pollution is being processed in the Gulf.

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“Red Herrings” in the Gulf of Mexico – Part 1: It Ain’t the Oil

By / Bio / Published: September 13, 2010

This is the first post in a four part series discussing the ongoing – and “cascading” – effects in the Gulf, not from oil, but rather its toxic components and their impacts on sensitive ecosystems. Read the rest of the series.

In recent weeks, nearly every discussion about the BP Oil Disaster in the Gulf of Mexico has focused on the question: “how much of the oil from the broken well is left in the Gulf?” 

The answer is simple:  “None – it ain’t the oil, stupid!”    

For some time now,  the problem hasn’t been the oil in the Gulf,  it’s the complicated series of impacts caused by the diverse substances that made up the oil as they are degraded in stages, both biologically and chemically. Each step along the way – and even the final breakdown products – poses important threats to a different suite of living things.  The total damage done by this complex array of shifting impacts on the sensitive ecosystems  and the people of the Gulf remains largely unknown.


Sure, some elements of the complex ecology of the Gulf of Mexico may get off scot-free from the disaster.  But many others have been or will be heavily impaired, at least for some time.  Taken together, there will be a significant total effect on the ecological systems of the Gulf, including the productivity and safety  of seafood, and significant  bottom-line impacts will be felt  on human health and social and economic well-being. 

Oil or Not Oil?

From the beginning of the disaster back in April, as “Gulf Light Sweet Crude” oil spewed  into the depths of the Gulf, the components of that oil – a “toxic soup” of hundreds of different chemicals – have been subjected to intense physical, chemical and biological sorting and processing, and to transportation by currents both towards and away from shore. 

This is an underwater look at one of the oil plumes in the Gulf of Mexico in late May. Click to watch the video.

By the time the well was capped in mid-July, a significant amount  of the approximately 200,000,000 gallons of liquid flowing from the broken well made it to the surface as recognizable oil.  But from the very beginning, the various “toxic soup” ingredients have followed radically different pathways through the complex oceanographic and living systems of the Gulf, spreading and being processed in different directions at different depths, and at different rates.

It is clear that all layers of the sea in a large zone around the well have been exposed, from bottom to top, as the spreading and rising cone (or “plume”) of oil-based materials spewed from the well. In contrast to a more typical oil spill on the water’s surface, where the transport and ecological fate of oil components are well-known, there are still many unknowns related to how the various chemicals have moved and are breaking down underwater, including the biochemical pathways and timetables.  Intense scientific investigation and complicated modeling are necessary before these complex relationships can be understood fully.

The addition of dispersants, both at the bottom and the top of the water column, has further altered the chemicals’ pathways through the ecosystem,  likely lessening some kinds of impacts and exacerbating others.It may well turn out that chemicals derived from oil spread over a much larger area because of the addition of dispersants, both at the bottom and the top.  The final accounting of the ecological and human winners and losers has yet to be made.

At the end of the day, the complex set of effects on the living systems of the Gulf from the oil and its chemical components will be understood, more or less.  The impacts on the human populations will be estimated, if not fully understood.  It is grossly premature to declare victory, though, until we understand the ways in which the basic fabric of the ecosystems of the Gulf has been altered, and what might be required to restore its weave.

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Deepwater Corals Are Out of Sight, But They Shouldn’t Be Out of Mind

By / Bio / Published: July 1, 2010

Credit: Steve W. Ross (UNCW), unpubl. data.

Among the unseen and uncounted victims of the BP oil disaster in the Gulf of Mexico are the inhabitants of the ancient deepwater coral reefs that lie under the still-growing plume of oil.  Newly discovered, and still largely unexplored, these “rainforests of the deep” may become polluted and degraded before we even know exactly where they occur.

Deepwater wonders

Deepwater corals were first discovered in U.S. waters in the 19th century, during the early voyages of discovery, but only in the modern age of deepsea submarines and remotely operated vehicles did exploration truly begin.

Credit: Steve W. Ross (UNCW), unpubl. data.

As exploration has unfolded, scientists have been amazed at the extent and character of these underwater wonderlands, with new species being discovered with nearly every dive, including unknown forms with the potential to contain novel chemicals with pharmaceutical applications.  A cancer cure may lie in the darkness of the deep sea. 

Additionally, the branches of millennia-old corals have recorded in their layers an unequalled history of the recent life of the planet, including deepsea conditions that will allow ancient climates to be modeled.

 

Gulf of Mexico coral reefs

Credit: Geoplatform.gov

Credit: USGS

 Click images for larger view

The best-known deepwater reefs in the Gulf are located in the Viosca Knolls region, on the northern edge of the DeSoto Canyon, only twenty miles from the blown-out BP well, and on the edge of the Mississippi Canyon west of the blowout site.  In addition, there are known deepwater reefs off the West Florida Shelf and elsewhere in the Gulf.  Exciting research is currently underway in the Gulf, including the deployment of “lunar lander” data recorders for year-long stays on the bottom near the reefs, which could provide badly needed baseline information for pre-blowout conditions.

See a thorough analysis of coral reefs in the Gulf, Southeast and elsewhere here.

Toxins raining down on corals

The deepwater origin of the BP oil disaster, the use of dispersants at the wellhead, and the resulting development of sub-surface plumes of oil-based pollution floating and drifting with sub-surface currents, mean that Gulf deepwater corals are at serious risk of direct degradation from the broken well, including a wide array of materials that would likely prove toxic to them. Normally, at least some of the toxic substances from an oil spill would evaporate as oil sits on the ocean surface, but in this situation, many of the toxins remain dissolved, emulsified or otherwise entrained in near-bottom waters and middle depths, drifting with the currents and potentially exposing deepwater reefs.   Coral’s naturally slow growth rates and uncertain reproduction means that any damage would be difficult if not impossible to remediate or offset.

To make matters worse, oil that does make it to the ocean surface doesn’t stay there.  While some of the toxic material on the surface is burned or evaporated, much is again treated with dispersant chemicals, forming smaller droplets that easily stick to debris raining into the abyss.  In addition, a significant fraction of weathered oil also ultimately sinks back to the depths of the ocean. Although estimates vary widely, the best guess is that 25-30% or so of the oil from the 1979 Ixtoc 1 blowout in Campeche Bay in the southwestern Gulf sank to the bottom.

Credit: LUMCON

Another real threat comes from the decomposition of oil-based organic matter under water.  “Dead zones” are well-known in the shallower waters of the northern Gulf, driven mostly by nutrients and organic matter from the outflows from the Mississippi River.  In this case, underwater “dead zones” at a variety of depths are likely, and could add an additional punch to fragile ancient corals.

Protecting deepwater treasures

Credit: SAFMC

Ironically, as Gulf coral reefs face an uncertain future, thousands of square miles of reefs are being protected in a new program nearby in the Southeast Atlantic. I had the great privilege of chairing the panel responsible for this magnificent advance. 

Over the past decade, a unique collaboration of academic researchers, managers and fishermen have worked together to craft a landmark protection program for 23,000 square miles of deepwater reefs stretching from North Carolina to Florida.  The National Oceanic and Atmospheric Administration approved these protections just this month, which will protect the coral reefs against fishing and many non-fishing threats.  While this designation by itself does not guarantee that oil and gas drilling could not occur there, it means that risks to those corals would have to be taken into account during lease sales and other project planning and design.

Two of the many researchers instrumental in securing these coral protections—Dr. Steve Ross from UNC Wilmington and Dr. John Reed from Harbor Branch—have each published their corals research online.

Corals in the crosshairs

The bottom line, sadly, is that ancient Gulf of Mexico coral reefs lie in the crosshairs of oil pollution from the BP oil disaster and it will be some time before scientists are able to begin damage assessments.  Research cruises scheduled for September may begin that process.

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BP Oil Disaster Is Not A Spill. More Like A Catastrophe.

By / Bio / Published: July 1, 2010
BP Oil Disaster Clean Up Efforts

BP Oil Disaster Clean Up Efforts

When the Deepwater Horizon drilling rig exploded on April 20, killing 11 people and injuring 17 others, it began a massive disgorgement of oil.  A full two months later, the oil continues to surge into the Gulf of Mexico at a rate that BP estimates of up to 100,000 barrels per day.

This disaster was and continues to be no ordinary oil “spill” or “leak.” A “spill” is something that happens on your kitchen floor and is easily mopped up and dried, or when a ship wrecks and dumps a certain amount of oil. A “leak” is what happens under your bathroom sink, remedied with some duct tape or at worst, a call to the local plumber. A “leak” may also be small amounts of oil that trickle from underwater oil pipelines. 

What is happening in the Gulf is nothing short of catastrophic.  An ecological “game-changer.”

Current estimates place the amount of oil that has flooded into the Gulf at more than 100 million gallons to date, and perhaps three times that amount – a staggering figure that makes the Exxon Valdez disaster (a total of 11 million gallons of crude) pale in comparison. Until now, the Valdez “spill” was widely known as the largest in U.S. history. By the time the flow is stopped, the catastrophe in the Gulf may well constitute the largest oil disaster in the hemisphere, and perhaps the world.

The evolution of the Gulf Loop Current from a strong downstream delivery phase on May 7 to a cutoff eddy phase on June 11, temporarily detaining oil pollution. Credit: NWS.

The endlessly expanding oil slick – which continues to spread far beyond the immediate area of the well, propelled by the Gulf Loop Current – covers thousands of square miles and has created underwater plumes that have proven exceedingly difficult to measure, let alone contain. 

Large amounts of oil have been sucked into the large eddy that formed from the northern part of the Loop Current, fated to drift northwestward towards Texas.  Only the chance development of this eddy on June 1 prevented oil pollution from reaching as far downcurrent as northern Cuba, Florida and beyond.

Only time will tell the final measure of this catastrophic blowout,  and its lasting damage to wildlife, the Gulf environment, fisheries and the regional and national economies.

But this much we can say: Characterizing what’s happening in the Gulf as a “spill” is like calling Hurricane Katrina a “shower.”

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Unseen Victims of the BP Oil Disaster

By / Bio / Published: June 28, 2010
 

Floating mats of seaweed, known as sargassum, are home to a wide variety of ocean life. Credit: Steve W. Ross (UNCW), unpubl. data.

The daily count of sea creatures dying from coating with oil on the surface of the sea, or on the beaches, continues to rise.  We see sea turtles, sea and shore birds, and marine mammals, familiar creatures to us all.

As sad as these deaths are, the death toll is massively greater for animals not quite as visible, because they are small, living among marsh grasses, or under the surface of the sea, out-of-sight and thus out-of-mind.  The full litany of the dead is deeply disturbing.

Surface currents carry valuable life

The surface waters of a healthy Gulf swim with life, much of it too small to see.  Larvae of shrimp, crab, and other shellfish, and many familiar seafood fishes, spawned at sea, drift toward nurseries in coastal marshes and other shallow waters. Floating mats of seaweed, called sargassum, provide key habitats for babies of many species, now hopelessly contaminated. The interior and underside of these seaweed mats – under normal conditions – are wonderlands of life, as every offshore fisherman knows.

  
The evolution of the Gulf Loop Current from a strong downstream delivery phase on May 7 to a cutoff eddy phase on June 11, temporarily detaining oil pollution. Credit: NWS.

The Gulf Loop Current – a term now commonplace– is a superhighway in the sea for spawned babies of giant tunas, swordfish and other billfishes, groupers, snappers and other reef fishes, and even for hatchling turtles. These creatures ride the current —our version of Nemo’s East Australian Current— toward adult habitats, at risk as they pass through the ‘kill zone’ of oil in the northern Gulf.  

See an animation of the current loop here and see a video of the oil spreading here.

This figure represents the evolution of the Gulf Loop. Credit: NOAA.

Luckily, the chance development on June 1 of a cutoff eddy—a normal phase in the evolution of the Gulf Loop Current, where the current bends deep enough to interact with itself, ultimately cutting off a spinning gyre in the northern Gulf—has delayed the otherwise rapid delivery of oil pollution to the pristine coral reefs, mangrove swamps and seagrass beds of northern Cuba, the Florida Keys and beyond.  Delivery of oil downcurrent to those habitats remains likely, as the Gulf Loop redevelops.  In fact, the weathered oil currently held in the cutoff eddy will likely drift northwest towards the Texas coast.

The beauty, and now oil, down below

An actual track of a sperm whale diving through rich mid-water feeding zones (shown in green) from the northern Gulf of Mexico. Credit: Modified from Azzara, 2006.

Under the surface, hovering clouds of oil pollution drift with the currents, and threaten perhaps the least known elements of this magical world.  At middle depths, a profusion of life – shrimps, lanternfish, jellyfish and squids –create a layer of life so rich it appears as sonar returns to surface ships, earning the name “deep scattering layer” to scientists.  This rarely imagined world of the deep – key prey for surface diving whales, dolphins, sharks and tunas – is now being contaminated twice, as oil pollution rises to and through it, and as sinking particles carry toxicants back downward.  It is no surprise that sperm whales and other deep-feeding life forms we cherish are now numbered among the dead. 

Deepwater treasures contaminated

The Visoca Knoll coral reefs are near the Deepwater Horizon well and are home to a rich variety of life. Credit: Steve W. Ross (UNCW), unpubl. data.

On the bottom, the corals and worms get the short end of the slick.   The deep-origin oil spewing from the crippled well is polluting deepsea wonderlands that are just now being discovered, notably majestic and ancient deepwater coral reefs. The vast majority of the oil that remains in the sea will ultimately find its way to the seafloor, where worms and other sediment-eating life forms will ingest it, be ingested in turn, and continue contaminating food webs – and the very web of life – for generations to come. 

This spill impacts you, too

Put all together, every important part of the broader Gulf of Mexico marine ecosystem – upon which so many people rely for their income, and their way of life – is taking many potential knockout blows.  Productivity of key seafood species could be depressed for years if not generations to come.  Special care will be required to ensure that Gulf seafood remains safe.  There is plenty to cry about, both on the surface and in the unseen places in the deep.

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Catch Shares Improves Both Science and Catches

By / Bio / Published: February 25, 2010
EDF Senior Scientist, Doug Rader

EDF Chief Oceans Scientist, Doug Rader

The track record for catch shares in fishery management is abundantly clear: better science for managers and better access for fishermen.  Certainly, “science vs. catch shares” is a false choice – catch shares provides the best chance to achieve high-powered science while getting fishermen back on the water and back to work. 
Here’s why.

Science in Fisheries Management

Irrespective of the type of management being used, federal law and regulations require that fishing levels be set to both prevent overfishing and rebuild overfished stocks, based on the best available scientific information.  The total fishing mortality for all fishing sectors (commercial, charter boats and private anglers), including both landed and discarded dead fish, cannot by law exceed “overfishing limits” identified by fisheries scientists.

Two kinds of information are used to assess fish stock conditions and set the overfishing limits, fishery-independent data (collected directly by scientists to judge stock conditions), and fishery-dependent data (sampling of fish caught by fishermen, and affected by the fishing mechanism and regulations, typically using catch monitoring or catch accounting methods).  Each type provides different, valuable information about what’s out there, and what is caught.

When there are lots of data of both types, and they are collected using robust methods, the uncertainty in the biology is greatly reduced and we have a much better understanding of what’s happening.  When data are poor in one or both categories, there is a higher level of biological uncertainty, and less confidence that managers understand what’s really occurring in the fishery.

Under federal regulations, biological uncertainty must be subtracted from the overfishing limits to create lower “allowable biological catches” that cannot be exceeded by managers. 

In addition, there is often considerable uncertainty in estimating how a proposed management system will work to achieve allowable biological catches.  Management uncertainty (how well management measures like bag limits, size limits, closures, or catch shares perform in actually hitting management targets) must be subtracted from allowable biological catches in setting “annual catch limits” for fisheries or fishing sectors.

Thus, all types of uncertainty must be accounted for.  The greater the total uncertainty, the lower the allowable catch levels can be—and the less fish for fishermen to catch, for any given stock condition. 

Finally, the levels of fishing allowed for overfished stocks are also set based on how fast those stocks are able and required to rebuild.  In nearly every case, the regional fishery management councils have allowed the longest legal rebuilding time, with the lowest allowable probability of actually rebuilding, given the biological uncertainty involved (50% probability, established in the courts and now by regulation), and the highest legal landings, even though that slows down rebuilding. Read More »

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