Environmental Impacts of Oil in the Gulf

00:00 June 30, 2011
By: Dionne Charlet

On Wednesday, June 8, 2011, oil was found floating near Breton Sound in Plaquemines Parish.   The source of this recent oil is as yet undetermined.

Since April 20, 2010, we as a Gulf Coastal Community have been awash in oil spill coverage.  A thick sheen of headlines and photos abound, often chronicling events with angles from the thought-provoking to the heart-wrenching.  Social networks perpetuate facts mingled with rumors, fears and blanket statements.  BP and the GOP send out reassurances as wildlife, family and friends endure losses.  What is actually happening with our ecosystem?  What is being done?  What future can we expect for our environment?

The potential impact of recent and historical spills, particularly the BP disaster located in the Gulf of Mexico’s Macondo Prospect, can best be reflected upon through the eyes of two of the most highly respected and sought-after environmental experts hard at work addressing the hazards and studying the effects of the exposure of large amounts of crude oil on the Gulf Region and beyond.  Robert A. Thomas, Ph.D, Professor and Director, Chair of the Loyola University Center for Environmental Communication, and Edward Overton, Ph.D., Professor Emeritus with the Department of Environmental Sciences, LSU School of Coast and Environment, each give in-depth insights to some hard questions:

WYAT:  What is known about the recent oil found floating near Breton Sound?

Overton/LSU:  “We collected one sample that was brought to us by the National Wildlife Federation.  We fingerprinted it and found it to be not from the Macondo spill.  It was a very fresh oil that could not have been in the environment very long.  Careful evaluation of the biomarkers showed that they did not match with the Macondo oil.  Biomarkers are chemicals that are not generally affected by the weathering process.  Biomarkers are inert and they stick around.  They are the last things to go as oil is degraded.   We can use those to see if this sample came from the same sources as Macondo oil.  Oils have slightly different biomarker patterns depending on where they came from out of the ground.  This was definitely not Macondo oil.”

WYAT:  What do you feel are the most problematic lingering effects of the Deepwater Horizon spill?

Thomas/Loyola:  “The lingering problem is that we do not know the response to the oil by the Gulf ecosystem.  Although things look good at the moment, we know from the Exxon Valdez experience that the herring fishery held steady for three years, then collapsed and has not recovered in all the years since that time.  What will happen to our very valuable fisheries, and what is happening to the non-economic components of the Gulf ecosystem?  Scientific studies have not as yet been able to answer these questions.”

Overton/LSU:  “Certainly the impact to the offshore fisheries.  The reason I say this is because the most dangerous kind of oil is fresh oil.  As oil enters the environment it undergoes a series of compositional changes that scientists call ‘weathering’.  Those changes make oil less dangerous.  Oil that came ashore during the BP event was pretty heavily weathered.  Oil that came up both offshore and in the deep ocean was not. Those environments offshore were experiencing the fresh oil, so that’s bad news for the offshore species.  The good news half of that equation is that the biological density offshore is much less than the biological density in the marshes and coastal environments.  Fish are pretty widely spread out."

WYAT:  How long does it take oil to weather?

Overton/LSU:   “Well, it is not a linear process.  The very light components–and remember:  the Macondo oil was a very, very light crude oil, so about 50% of it may weather in a couple of days or so.  It then mixes with water and forms the emulsion.  Weathering the rest of the oil takes much longer:  weeks to months.  Much of this emulsion meandered around offshore, and eventually some of those patches of this oil that were meandering offshore came ashore.  What came ashore—that oil—was not nearly as dangerous as it would have been if it would have been fresh oil, so I know it did less damage than it would have done if it were fresh oil.  Now, the real question is, how much damage was done on the coastal marshes?   We really have to wait and go through a couple of growing seasons to see.  We are already seeing a lot of encouraging signs in areas that were oiled along the fringe of the marsh.  There is green regrowth there, but there are some areas that were really heavily oiled where we don’t see regrowth, and that means that the oil killed the roots of the plants and so the plants are dead.  Where the regrowth occurred, oil killed the leafy structure but not the roots so the plant is regenerating itself.  Fortunately those heavily oiled areas are relatively small, but it is a horrible mess right there, but it is not all over the coast.  Far from it.  It is relatively small areas that were really heavily impacted.  That is why I am cautiously optimistic that we dodged a really bad bullet and the damages are going to be less than we thought last year because this weathered oil came ashore, but a lot of coastline is showing regrowth and that is very good news.

When oil comes ashore, the thicker the oil you’ve got in any one spot, the worse it is.  So, a little bit of oil coming ashore doesn’t cause nearly as much damage as thick, globby, concentrated oil.  The thicker oil smothers everything it touches.  Also, as the oil is degraded, it uses up oxygen, and, in some of these areas if oxygen levels in the water are kind of marginal to start with and there is a lot more organic matter than can be degraded by natural bacteria, then the little bit of the oxygen that is there gets used up and the sediments go anaerobic, which is a fancy way of saying they don't have enough oxygen.  It is smothering and there is oxygen deporation down in the root structures and in the places where all the little critters live that you and I never see but that support the base of the food chain.”
WYAT:  Please provide any insights to some of the effects of oil on birds, marine plants, mammals and fish, land-dwelling animals and plants, including humans.

Thomas/Loyola:  “There are no valid data on this topic, but many scientists are at present tracking populations and sampling the environment—gathering data that will be useful in answering this very important question.  Some birds died, but the bird population, as far as we know, is doing okay.  There should be no concern that birds of any species will be extirpated.  For fish, the main concern is what happened to last year’s eggs and larvae.  The adults can be doing quite well, but there may be no juveniles coming behind them.  Or, as in the herring in Prince William Sound after the Exxon Valdez, they may crash in a year or so and be devastated.  No concern about whales, but we keep hearing in the news about high numbers of dolphins and their babies dying.  A preliminary suggestion notes the co-occurrence of the dolphin deaths and the melting snow and ice dropping the temperatures of water flowing out to Mobile Bay by about 14 degrees.  Unfortunately, the carcasses are being stored and thorough autopsies have not been performed.  Also, we don’t know if the number of dead dolphins is typical or if we are seeing many more than normal due to many, many more observers reporting them.  We have no hard data to explain the increased number of aborted babies being reported, but the public assumes that something the water (hydrocarbons, dispersants) is causing them to abort.”

Overton/LSU:  “Detecting damage is a lot easier to say than to do.  We can surmise there is damage because we know that fresh oil kills these larval species.  Being able to detect that in the environment in terms of population, numbers is a lot easier to say than to do.”

WYAT:  Has Corexit yet proven to be harmful, or are there lingering side effects possibly due to the dispersant?

Thomas/Loyola:  “No verified reports of residual harm at this time.  A number of studies are underway.”
Overton/LSU:  “When dispersants are used, you are making a choice between the lesser of two evils.  In using dispersants in deep water, far offshore, you are spreading floating oil down into the water column, and this provides an opportunity for animals living in the water column to be exposed to the toxic compounds in oil.  However, dispersed oil does not wash ashore and cause much greater environmental damage, and much more longer lasting impacts.  So, normally, the decision is to disperse offshore to protect onshore environments.”

WYAT:  What foreseeable environmental impacts do you believe will result from the oil?

Thomas/Loyola:  “In the absence of scientific analysis, this question can only elicit speculation from the perspective of the respondent.  We know that there have been fewer than expected acute impacts on our coastal marshes, but only time and studies will help us understand the chronic impacts.  The critical areas of concern are the as yet unseen, not analyzed impacts of commercial fishery eggs and larvae and the plankton communities.  Add to this the ecosystem components that support the aforementioned.  Many wetland scientists assume there is no lasting, increasing harm done to our coastal marshes, and a host of scientists are monitoring that area of study.

Based on the long history of oil exposure in the Gulf ecosystem, I’m hoping we won’t see long-term, chronic devastation.  That said, the onus is on the oil and gas industry to improve their operations so that they are more vigilant and have an improved response plan.  After all, the Ixtoc catastrophe of 1979 showed how unprepared the industry was for a blowout, and 31 years later the BP Macondo well duplicated their failed corrective procedures with the same results.  This response should never happen again.”

Overton/LSU:  “It is too early to say absolutely for certain.  None of us know absolutely but we can offer educated guesses.  This is not just the first dance on the oil spill.  We’ve been dancing with oil for a long, long time in my group here at LSU.”

Dr. Bob Thomas served as chair of the Environmental Advisory Committee of the Strategic Petroleum Reserve.  He was the founding director of the Louisiana Nature Center.  He has been actively engaged in local environmental issues since 1977.  For info on the Loyola University Center for Environmental Communication, go to www.loyno.edu/lucec <http://www.loyno.edu/lucec> .

Dr. Ed Overton is the resident expert on oil spills.  He was named 2010 Communicator of the Year by the Public Relations Association of Louisiana after giving literally hundreds of interviews during the BP Event, even appearing as a guest on the Dave Letterman Show.
For info on the LSU School of Coast and Environment, go to www.sce.lsu.edu <
http://www.sce.lsu.edu> .