09 Jun 2010: Interview

The BP Spill’s Growing Toll
On the Sea Life of the Gulf

A prominent marine biologist says the impacts of the oil gushing into the Gulf of Mexico will persist for years, no matter when the flow finally stops. What’s more, scientist Thomas Shirley says that most of the damage remains out of sight below the surface, as creatures succumb to the toxic effects of the rapidly spreading tide of oil.

by david biello

Thomas Shirley of Texas A&M University has spent most of his career studying the aquatic life of the Gulf of Mexico. Indeed, shortly before the Deepwater Horizon oil spill, Shirley was part of a team of 140 scientists from 15 countries that completed an all-species inventory of the Gulf, from phytoplankton to sperm whales. Despite decades of intensive oil drilling, the inventory showed that the Gulf of Mexico still harbored 15,700 species of sea life. In the area immediately surrounding the spill, Shirley and his fellow scientists tallied 8,332 species of plants and animals, including more than 1,200 fish (such as the Atlantic bluefin tuna), more than 1,500 crustaceans (including the blue crab), and 29 marine mammals (including bottlenose dolphins).

But the massive amounts of oil spewing from the ruptured Deepwater Horizon rig are already having a “devastating” effect on marine life in the
Thomas Shirley
Gulf, according to Shirley. The oil, coupled with the dispersants designed to break it up, will — at least in the foreseeable future — deal a serious blow to the foundation of this ecosystem: the tiny plants and animals known as phytoplankton and zooplankton. "When you start removing pieces of this big food web out there, what’s going to happen?" asks Shirley, who holds the endowed chair in biodiversity and conservation at the Harte Research Institute, which is dedicated to studying the Gulf of Mexico. “We don’t really know, but likely not good things.”

In an interview with Yale Environment 360 contributor David Biello, Shirley discusses how entire generations of shrimp, crab, oysters, and other commercially important marine life may be wiped out and take years to recover. Much of that devastation will remain invisible to us, as creatures from sperm whales to sea turtles may die from the effects of the oil and sink beneath the waves without a trace.

Shirley says that, despite the Gulf’s warm waters and indigenous population of oil-eating microbes, the impacts of this oil spill are likely to be felt for a long, long time — especially if a hurricane blows the oil deep into Gulf Coast wetlands. “If this oil spill ends up back in the marsh areas that are nurseries for a lot of these species, we will see very long-term effects,” says Shirley, who also studied the impacts of another famous oil spill — the Exxon Valdez off the coast of Alaska. “Twenty-one years later we still see effects [of the Exxon Valdez]. I predict long-term effects here.”

Yale Environment 360: Gven your recent survey of the marine biology of almost the entire Gulf, what’s your assessment of the damage to date?

Thomas Shirley: Well, I really don’t have hard data on damage. The only thing we have so far are body counts of the oiled birds, questionable data about the causes of deaths of many marine turtles and a few marine mammals. But, no doubt with this amount of oil in the water there have been many mortalities at all trophic levels — crabs, shrimp, fishes. Lots of things that are small and out of sight of most people, but are important in food webs.

e360: The estimates are now, if you take the high end of the government [estimate], roughly 40 million gallons of oil out there in the Gulf somewhere. What’s your assessment of what the impact on the whole ecosystem will be over time?

Shirley: It will be devastating. But again, most people are not aware of the workings of the ecosystem. And so, to most people all they will see is oiled birds or animals that wash up on shore. What I will see and be concerned about are losses in production of shrimp and crabs and fishes for next year and the year after.

e360: When you say “devastating,” what does that mean? Does that mean that the population is cut in half or the population is poisoned, or does it mean that there won’t be any shrimp next year?

Shirley: Well, within this [affected] region of the Gulf — and that’s now getting to be a sizeable portion of the Gulf — there will be losses of next year’s year-classes of shrimp and crabs. Those that would have been hatched and grown up this year will not be present next year. Some of them will have died as eggs or as larvae or juveniles. Others would never have been produced because each of the parents died or the parents used that energy to fight the toxicity of the oil and disperse it.

e360: What is killing the larvae and the parents? Is it the oil itself or is it some of these dead zones that might be developing?

Shirley: Most likely [it] will be oil, particularly in the deep plumes, but at the surface also. Surface waters [are] where we have the highest productivity, and by that I mean primary production of phytoplankton is
If we start losing parts of the system, it’s not going to work quite as it’s supposed to.”
going to be affected. But right immediately under that is all the zooplankton, [and the] larval fish that depend upon the zooplankton for food, [and] the larval shrimp that depend upon them for food. Those are the things that are taken out by contact with the oil, and the oil that’s in solution now because of the dispersants, and these big plumes. Although both BP and NOAA [the National Oceanic and Atmospheric Administration] are as yet questioning the deep plumes, saying there is no data. I think the data are all there.

People are out there taking water samples even as we speak. And the water samples come up heavily laden with oil and gas. And, I think in the next few days we’ll have signatures of those oil samples that confirm that it’s from the Deepwater Horizon oil. Most people are not aware that zooplankton [engage in] vertical migration. [They] move up and down in the water column. In fact, there’s a whole series of different migrations. But they move up and down through the water column for hundreds of meters. And so these animals are moving through these plumes of oil and gas, and being exposed to it.

e360: What is going to bear the brunt as far as sea life goes? Is it the smaller organisms? Is it the larger organisms that perhaps bear the impact of bio-accumulation of some of these toxics?

Shirley: They all will. There’s not really bio-magnification of oil. There’s a bio-concentration that can increase in each particular organism. As they come into contact with more oil or consume it, they can build up oil in their tissues. But that is not magnified in the next trophic level. In fact, if you traced oil content into higher trophic levels, often as you go up the food web into larger and larger predators, there is often a decrease in the content of oil. It doesn’t mean that they’re not affected, either by contact or by food, but it’s not bio-magnified like you would see for metals or pesticides.

e360: What about spawning areas? How will they be impacted by the oil? Is it simply the fact that perhaps larval fish will try to eat the oil or is it more the physical coating, either of the fish itself or the surface?

Shirley: Well, all of those things and more. So some of it will affect food. Some of the fish will actually nip at little gas or oil droplets, and see that as potential food sources and consume that. That’s already been reported although not really quantified in any scientific experiments. But divers have already observed different species of fish biting oil droplets. It will affect their food and then through indirect effects. Some of the food that would have been present for them will not be present. Often, fish that have come into contact with oil have decreased sensory capabilities. So it affects either vision or taste or smell, and they are not as good at finding food. And then part of their energies are being used to combat this oil that they’ve taken into their system instead of using that energy for growth or later on for reproduction. So [there are] a lot of different ways oil can affect the organisms.

e360: Is there a difference between how it will impact in, say, the spawning areas versus the deeper sea or further out in the open ocean?

Shirley: Not really. In spawning areas, you would simply have early life history stages, either gametes or larvae or juvenile concentration in those areas. And, frankly, we don’t know where all of those areas are for the different species. You know, for commercially important species we know pretty well where things happen, but not even all of those. But what we
One hurricane could change [everything]. If this oil ends up in marsh areas, it could have very long-term effects.”
don’t know are all of the trophic links. So one of the things that we like to compare this to, if you ever take apart a watch and you have all these different gears and different mechanisms, little wheels up to big wheels, and they all work together to produce a nicely functioning watch. If you put the watch back together without those little parts, it’s not going to work. And we often don’t know what all those little wheels and spokes are. And in this case we’re talking about the different smaller animals, the zooplankton, and the different kinds of plankton. But they’re part of the mechanisms that contribute toward a functioning ecosystem. If we start losing parts of the system, it’s not going to work quite as it’s supposed to. We will be limping along, so to speak.

e360: And, you mentioned the commercially important species. So let’s go through some of them. I understand that it’s spawning time for the bluefin tuna. What does this mean? Does this mean that the Japanese aren’t going to enjoy Atlantic bluefin tuna sushi next year?

Shirley: Well, they’ve already taken out 80 percent of the stock and it’s not just the Japanese, it’s fishing fleets around the world, but the Japanese are the primary consumers. And the Gulf of Mexico is one of two spawning areas for the North Atlantic bluefin tuna. So, yes, I am fairly certain that the area around the Deep Horizon is not a spawning area. In fact, I’m sure that’s not the case. But the later life history stages may well be exposed. And the [satellite-] tagged tuna certainly utilize the Loop Current, and if they follow it around, there is a strong possibility they will be exposed to oil.

e360: Does that mean that we shouldn’t eat them or, like you said, since the bio-magnification isn’t a threat here, is it relatively okay to eat those bluefin?

Shirley: Oh, I think all of the fish that go to the market will be tested, and I think that our own sensory capabilities are much more sensitive even than any of the testing. So I think that most of the food from the sea that will be harvested will be tested and it will be okay.

e360: What about oysters and shrimp and the other commercially important seafood that contributes so much to the seafood of the entire United States?

Shirley: We have three species of shrimp that are commonly harvested; brown shrimp, white shrimp, and pink shrimp. And, of course, the American oyster and the blue [oyster]. Those are five prime products that most people think of when they think of the Gulf harvest of seafood. [The spill is] already closing down the exporters in that region. So there are widespread effects throughout the country. Over here in Texas, where we have our own oyster production, it’s very difficult to find oysters now. I know the rest of the country is also feeling the effects.

e360: How long do you think before all of these species, not just oysters, are back at commercial levels?

Shirley: Well, I think first of all we have to know how long the oil spill is going to continue, and we need to see where it finally ends up. One hurricane two weeks from now could change all of our considerations of the spill. If this oil ends up back in marsh areas that are nursery areas for the life history stages of some of the species, or the coast oyster reefs, which are typically back in bays and estuaries, it could have very long-term effects. But we’re working pretty much in the face of uncertainty right now, until we cap the well and know something about the volume of oil and learn about where it’s going to end up.

I think most people are not aware that the Loop Current changes in intensity. Early in the year the Loop Current had a fairly low current speed. That will be picking up as we progress into the summer. And, that
We see portions of the damage but you have to realize that many more have died.”
will be generating more eddies that spin off, some to the west, some to the east. And some of those eddies could very well carry this oil back to other Louisiana estuaries probably to the west or to the Texas coast. As the current picks up, it could carry this oil to other areas of Florida. We really don’t know where it’s going to end up yet. So there are all kinds of dire scenarios that might occur.

e360: You mentioned that most people’s picture of the oil spill is going to be the oiled birds. But obviously the sea turtles and marine mammals are the other charismatic megafauna impacted by the oil spill. What will be the effects on them?

Shirley: It probably will be severe because these are long-lived species that have a low reproductive output. Sea turtles have to be pretty old before they even start reproducing. The Kemp’s Ridley turtle, most of the population is in the Gulf — these things are eight to 10 years of age before they begin to reproduce. So if we lose large numbers of them as a result of this spill, well, then recovery will be slow. I think most people aren’t aware of how many marine mammals there are in the Gulf.

There’s a population of about 1,600 sperm whales that occurs in the northern Gulf of Mexico. And a big part of their range is where the spill is now — there and farther to the west. And these large sperm whales are vertically migrating. They dive to about 400 meters to catch their food, prey items [like] squid and fish. These [whales] are going to be diving through the plume. Their prey vertically migrate and their prey could well be exposed to oil.

So they could either lose food sources, they could consume the food that’s tainted and therefore take it in themselves, or they could have direct exposure to it as they continually dive. Individual whales dive many times during the day to get their food. And these are also long-lived. They have a time span that is roughly similar to humans in terms of when they begin to reproduce, and how many offspring they have. And, of course, they can live much longer than humans, so recovery is slow. We don’t know if sperm whales will be affected by the spill, but judging from other spills around the world like in [the] Exxon Valdez, I strongly think that will be the case.

e360: Will we even know? I mean, with sperm whales obviously they’re pretty much living their lives out of sight. And if and when they do die, they pretty much sink to the bottom. Will we even know if they’re being impacted?

Shirley: That’s the case for most things. We won’t know what’s happened to them. Most people think that the oiled birds wash up on shore. Only a tiny fraction wash up on shore. Most of them sink out of sight. Just about everything sinks. And we know this for a fact because oiled birds and oiled mammals were tagged and released, dead ones, dead bodies, carcasses were tagged and released and only a small fraction were recovered. So we know that what we see has a strong multiplier affect. We see a portion of the damage and you have to realize that many more of them have died. So, yes, for most whales you’ll never see them if they die.

e360: How long do these impacts continue? Does it stop when the oil spill stops? Does it go on for decades?


The Gulf of Mexico Oil Spill:
An Accident Waiting to Happen

Oil Spill
The oil slick spreading across the Gulf has shattered the notion that offshore drilling had become safe. A close look at the accident shows that lax federal oversight, complacency by BP and the other companies involved, and the complexities of drilling a mile deep all combined to create the perfect environmental storm.

Under Pressure to Block Oil,
A Rush To Dubious Projects

In response to the widening disaster in the Gulf, officials have approved a plan to intercept the oil by building a 45-mile sand berm. But scientists fear the project will inflict further environmental damage and do little to keep oil off the coast, Rob Young writes.
Shirley: Well, I would preface it by saying we’re in warmer water here in the Gulf of Mexico. The ecosystem is adapted to oil. There’s a large natural seep that occurs throughout the Gulf. There’s a chronic exposure to oil. There is something like 50 million gallons a year that’s lost from natural seeps from about 1,500 sites around the Gulf naturally. So, that means that there are microbes adapted to breaking down the oil. That means that recovery here would be much faster than in areas that don’t have this chronic exposure to oil. But if we look at other areas like Prince William Sound, now 21 years after the Exxon Valdez in which there were only 11 million gallons lost. And, all of that at the surface, not coming from 5,000 feet, no deep plumes.

There are still 21,000 gallons of oil [in Prince William Sound] that you can dip your hand into that smells and it’s liquid. You can touch it. You can feel it. It’s still killing animals. It’s among the most toxic portions of the oil. Why isn’t it cleaned up? Well, because it’s buried under intertidal rocks. But sea otters that dig down and dig out clams, they’re getting tainted food and they’re getting into this oil themselves. And any other organisms that live in the shallows of tidal zone. That’s just what we know about: 21,000 gallons that’s still there. So with many more times the volume of oil here in the Gulf, there will be oil residues. There will be oil tar balls. There will be mousse. There will be oil that persists.

And, I dare say that the litigation over this will persist for decades. It’s still ongoing in Alaska, so we know that the environment is still being affected. We know that many species have not recovered there yet, some sea bird species, some fish species. They’re gone. So 21 years later, we still see effects. So I would predict that there will be long-term effects here. Most of the oil will be gone. Most of the Gulf will recover well, and in a span of just a few years, but the effects of this oil spill will persist for decades.

POSTED ON 09 Jun 2010 IN Biodiversity Oceans Oceans Policy & Politics Pollution & Health North America 


Could the oil get into the gulf Stream?

I now live in England. Could the oil get into the Gulf Stream and affect marine ecosystems around great Britain?

Posted by Mrs. Rebecca Woodell on 12 Jun 2010

This crisis has, as of this comment, continued for 68 days. President Obama has yet to declare it a National Emergency, yet it will likely be viewed as the worst man-made environmental disaster in history. Please urge our leaders to take control of the situation and give this catastrophe emergency status.

Online petition @ http://stopthespill.org/petition

Posted by Parker Jackson on 28 Jun 2010

I think that the oil spill is a disaster and that BP are not taking enough care of it. In the backround all the big oil compaines(the supermajors) will be talking to each other and sticking together for the next oil spill and are not doing alot to stop it.

Posted by Kent Fletcher on 19 Jul 2010

We only need divine solution becouse, the environment has been over strtched and human activities on the environment is not equal to what it can carry so definitely it reacts.

Posted by Danny Excell on 18 Aug 2011

i have been looking at tons of websites and reports and people seem to avioding the question. What is the data saying about the impact on marine life? They give vague statements on the subject. They its bad or disastorus but I want to know a number. It doesn't have to be exact. But I want them to say 'We're thinking around 8,000 animals have been poisoned. why won't somebody say it?

Posted by on 21 Aug 2011

this is a good article, though I would like to know the estimated guess of how many marine life died.

Thank you.

Posted by kaitlyn on 08 Jan 2012

Comments have been closed on this feature.
David Biello, who conducted this interview for Yale Environment 360, has been covering energy and the environment for nearly a decade, the last four years as an associate editor at Scientific American. He also hosts 60-Second Earth, a Scientific American podcast covering environmental news, and is working on a documentary with Detroit Public Television on the future of electricity. In previous articles for Yale Environment 360, Biello has written about geothermal technology and solar thermal technology and has explored the potential of extracting carbon dioxide from the atmosphere using “artificial trees.”



Out of the Wild: For India’s Captive
Leopards, A Life Sentence Behind Bars

As sightings of leopards in populated areas increase, Indian authorities are trapping the animals and keeping them in captivity — often in small cages without adequate food or veterinary care. The real solution, wildlife advocates say, is to educate the public on how to coexist with the big cats.

How Ocean Noise Pollution
Wreaks Havoc on Marine Life

Marine scientist Christopher Clark has spent his career listening in on what he calls “the song of life” in the world’s oceans. In an interview with Yale Environment 360, he explains how these marine habitats are under assault from extreme—but preventable—noise pollution.

Is Climate Change Putting
World's Microbiomes at Risk?

Researchers are only beginning to understand the complexities of the microbes in the earth’s soil and the role they play in fostering healthy ecosystems. Now, climate change is threatening to disrupt these microbes and the key functions they provide.

Beyond the Oregon Protests:
The Search for Common Ground

Thrust into the spotlight by a group of anti-government militants as a place of confrontation, the Malheur wildlife refuge is actually a highly successful example of a new collaboration in the West between local residents and the federal government.

How ‘Natural Geoengineering’
Can Help Slow Global Warming

An overlooked tool in fighting climate change is enhancing biodiversity to maximize the ability of ecosystems to store carbon. Key to that strategy is preserving top predators to control populations of herbivores, whose grazing reduces the amount of CO2 that ecosystems absorb.


MORE IN Interviews

Unable to Endure Rising Seas,
Alaskan Villages Stuck in Limbo

by diane toomey
As an advocate for Alaska’s Native communities, Robin Bronen points to a bureaucratic Catch-22 — villages cannot get government support to relocate in the face of climate-induced threats, but they are no longer receiving funds to repair their crumbling infrastructure.

Why CO2 'Air Capture' Could Be
Key to Slowing Global Warming

by richard schiffman
Physicist Klaus Lackner has long advocated deploying devices that extract carbon dioxide from the atmosphere to combat climate change. Now, as emissions keep soaring, Lackner says in a Yale Environment 360 interview that such “air capture” approaches may be our last best hope.

Bringing Energy Upgrades
To the Nation’s Inner Cities

by diane toomey
Donnel Baird has launched a startup that aims to revolutionize how small businesses and nonprofits secure funding for energy efficiency and clean energy projects in low-income neighborhoods. In a Yale Environment 360 interview, he talks about how he plans to bring his vision to dozens of U.S. cities.

From Mass Coral Bleaching,
A Scientist Looks for Lessons

by katherine bagley
For climate scientist Kim Cobb, this year’s massive bleaching of coral reefs is providing sobering insights into the impacts of global warming. Yale Environment 360 talked with Cobb about the bleaching events and the push to make reefs more resilient to rising temperatures.

For James Hansen, the Science
Demands Activism on Climate

by katherine bagley
Climate scientist James Hansen has crossed the classic divide between research and activism. In an interview with Yale Environment 360, he responds to critics and explains why he believes the reality of climate change requires him to speak out.

How Ocean Noise Pollution
Wreaks Havoc on Marine Life

by richard schiffman
Marine scientist Christopher Clark has spent his career listening in on what he calls “the song of life” in the world’s oceans. In an interview with Yale Environment 360, he explains how these marine habitats are under assault from extreme—but preventable—noise pollution.

How to Talk About Clean
Energy With Conservatives

by diane toomey
Angel Garcia, of Young Conservatives for Energy Reform, is working to persuade Republicans about the need for renewable energy. In an interview with Yale Environment 360, he explains why his group avoids mentioning climate change when it makes its pitch to conservatives

In Flint Crisis, A New Model
For Environmental Journalism

by cynthia barnett
Curt Guyette is an investigative reporter who dug deeper into the Flint water crisis. In an interview with Yale Environment 360, he explains his work as a journalist employed by a Michigan nonprofit and how it could be a model for in-depth, local reporting on the environment.

Rethinking Urban Landscapes
To Adapt to Rising Sea Levels

by winifred bird
Landscape architect Kristina Hill focuses on helping cities adapt to climate change, particularly sea level rise. In an interview with Yale Environment 360, she discusses the challenges, solutions, and costs of saving cities from encroaching oceans.

How Science Can Help to Halt
The Western Bark Beetle Plague

by richard schiffman
Entomologist Diana Six is focused on the beetle infestation that is wiping out conifer forests in western North America. In an interview with Yale Environment 360, she explains why the key to combating this climate-related scourge is deciphering the trees’ genetic ability to adapt.

e360 digest
Yale Environment 360 is
a publication of the
Yale School of Forestry
& Environmental Studies


Donate to Yale Environment 360
Yale Environment 360 Newsletter



About e360
Submission Guidelines

E360 en Español

Universia partnership
Yale Environment 360 articles are now available in Spanish and Portuguese on Universia, the online educational network.
Visit the site.


e360 Digest
Video Reports


Business & Innovation
Policy & Politics
Pollution & Health
Science & Technology


Antarctica and the Arctic
Central & South America
Middle East
North America

e360 VIDEO

Tribal people and ranchers join together to stop a project that would haul coal across their Montana land.
Watch the video.


The latest
from Yale
Environment 360
is now available for mobile devices at e360.yale.edu/mobile.


An aerial view of why Europe’s per capita carbon emissions are less than 50 percent of those in the U.S.
View the photos.

e360 VIDEO

Ugandan scientists monitor the impact of climate change on one of Africa’s most diverse forests and its extraordinary wildlife.
Learn more.

e360 VIDEO

Food waste
An e360 video series looks at the staggering amount of food wasted in the U.S. – a problem with major human and environmental costs.
Watch the video.

e360 VIDEO

Colorado wildfires
An e360 video goes onto the front lines with Colorado firefighters confronting deadly blazes fueled by a hotter, drier climate.
Watch the video.


A three-part series Tainted Harvest looks at the soil pollution crisis in China, the threat it poses to the food supply, and the complexity of any cleanup.
Read the series.