BP Deepwater Horizon Spill Accelerated Erosion Rate of Louisiana Marshes

University of Florida
The BP Deepwater Horizon oil spill temporarily worsened existing manmade problems in Louisiana's salt marshes such as erosion, but there may be cause for optimism, according to a new study.
A study appearing online Monday in the Proceedings of the National Academy of Sciences found the 2010 spill killed off salt marsh plants 15 to 30 feet from the shoreline and this plant die off resulted in a more-than-doubled rate of erosion along the marsh edge and subsequent permanent marsh habitat loss. Vegetation farther from shore was relatively untouched by the incoming oil.
"Louisiana is already losing about a football field worth of wetlands every hour, and that was before the spill," said Brian Silliman, a University of Florida biologist and lead author of the study. "When grasses die from heavy oiling, their roots, that hold the marsh sediment together, also often die. By killing grasses on the marsh shoreline, the spill pushed erosion rates on the marsh edge to more than double what they were before. Because Louisiana was already experiencing significant erosive marsh loss due to the channelization of the Mississippi, this is a big example of how multiple human stressors can have additive effects."
Marshes are the life's blood of coastal Louisiana because they act as critical nurseries for the shrimp, oysters and fish produced in these waters while helping to sequester significant amounts of carbon. They also protect coastlines from flooding and guard estuarine waters from nutrient pollution.
But the marshes have been suffering for decades as a result of the channelization of the Mississippi River, which has starved them from needed sediments to deter erosion.
Then came the oil spill.
Researchers observed minimal oil on the surfaces of grasses located more than 45 feet from the shoreline, indicating that significant amounts of oil did not move into interior marshes.
Instead, the researchers found that the tall grasses along the marsh edge acted as wall-like trap to incoming oil slicks, concentrating oil on the marsh edge. This concentration of oil on the shoreline protected interior marshes from oiling but worsened already extreme erosion on the shoreline. As oiled plants died, their roots that hold tight to the sediment perished as well. Already eroding sediment was now exposed to wave action without the effect of the gripping plant roots.
The result: elevated erosion rates for 1.5 years that averaged more than 10 feet of shoreline loss per year—double the natural rate for this area.
The encouraging results, Silliman said, included significant declines in the oil concentration on the marsh surface over 1.5 years and that unaffected, healthy marsh plants in the marsh interior quickly grew back into marsh die-off areas that had not yet been lost due to heightened erosion.
When the new marsh plant growth grew into the erosive edge of the marsh, Silliman said, the recolonization of the area by the gripping plant roots shut down the oil-elevated erosion rates and returned them to those seen at marsh sites where oil coverage did not occur.
The researchers also found that polyaromatic hydrocarbons, or PAHs, a carcinogenic byproduct of oil, was 100 percent greater at the Barateria Bay testing site than in reference marshes. This finding provides chemical evidence to support their visual observations that marshes in the affected areas were laden with oil while those in reference areas did not receive significant oiling.
By adding Biochar, a charcoal-based substance, to marshlands, Silliman's team is also using new bioremediation tactics to try to break down PAHs into organic material. If this method is successful, he said, it could be used to supplement naturally occurring microbes in the marsh mud that already oxidize the oil carcinogen. The team is soon to publish those findings.
"This is a new idea applied toward cleaning up PAHs," said UF chemistry professor Andrew R. Zimmerman, a co-author on the paper. "It's possible there's a bunch lurking at the bottom of the bay."
Visit EcoWatch's GULF OIL SPILL page for more related news on this topic.
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By Daisy Simmons
In a wildfire, hurricane, or other disaster, people with pets should heed the Humane Society's advice: If it isn't safe for you, it isn't safe for your animals either.
1. Stay Informed
<p>A first order of business in pet evacuation planning is to understand and be ready for the possible threats in your area. Visit <a href="https://www.ready.gov/be-informed" target="_blank">Ready.gov</a> to learn more about preparing for potential disasters such as floods, hurricanes, and wildfires. Then pay attention to related updates by tuning <a href="http://www.weather.gov/nwr/" target="_blank">NOAA Weather Radio</a> to your local emergency station or using the <a href="https://www.fema.gov/mobile-app" target="_blank">FEMA app</a> to get National Weather Service alerts.</p>2. Ensure Your Pet is Easily Identifiable
<p><span>Household pets, including indoor cats, should wear collars with ID tags that have your mobile phone number. </span><a href="https://www.avma.org/microchipping-animals-faq" target="_blank" rel="noopener noreferrer">Microchipping</a><span> your pets will also improve your chances of reunion should you become separated. Be sure to add an emergency contact for friends or relatives outside your immediate area.</span></p><p>Additionally, use <a href="https://secure.aspca.org/take-action/order-your-pet-safety-pack" target="_blank" rel="noopener noreferrer">'animals inside' door/window stickers</a> to show rescue workers how many pets live there. (If you evacuate with your pets, quickly write "Evacuated" on the sticker so first responders don't waste time searching for them.)</p>3. Make a Pet Evacuation Plan
<p> "No family disaster plan is complete without including your pets and all of your animals," says veterinarian Heather Case in <a href="https://www.youtube.com/watch?v=Q9NRJkFKAm4" target="_blank">a video</a> produced by the American Veterinary Medical Association.</p><p>It's important to determine where to take your pet in the event of an emergency.</p><p>Red Cross shelters and many other emergency shelters allow only service animals. Ask your vet, local animal shelters, and emergency management officials for information on local and regional animal sheltering options.</p><p>For those with access to the rare shelter that allows pets, CDC offers <a href="https://www.cdc.gov/healthypets/emergencies/pets-in-evacuation-centers.html" target="_blank">tips on what to expect</a> there, including potential health risks and hygiene best practices.</p><p>Beyond that, talk with family or friends outside the evacuation area about potentially hosting you and/or your pet if you're comfortable doing so. Search for pet-friendly hotel or boarding options along key evacuation routes.</p><p>If you have exotic pets or a mix of large and small animals, you may need to identify multiple locations to shelter them.</p><p>For other household pets like hamsters, snakes, and fish, the SPCA recommends that if they normally live in a cage, they should be transported in that cage. If the enclosure is too big to transport, however, transfer them to a smaller container temporarily. (More on that <a href="https://www.spcai.org/take-action/emergency-preparedness/evacuation-how-to-be-pet-prepared" target="_blank" rel="noopener noreferrer">here</a>.)</p><p>For any pet, a key step is to establish who in your household will be the point person for gathering up pets and bringing their supplies. Keep in mind that you may not be home when disaster strikes, so come up with a Plan B. For example, you might form a buddy system with neighbors with pets, or coordinate with a trusted pet sitter.</p>4. Prepare a Pet Evacuation Kit
<p>Like the emergency preparedness kit you'd prepare for humans, assemble basic survival items for your pets in a sturdy, easy-to-grab container. Items should include:</p><ul><li>Water, food, and medicine to last a week or two;</li><li>Water, food bowls, and a can opener if packing wet food;</li><li>Litter supplies for cats (a shoebox lined with a plastic bag and litter may work);</li><li>Leashes, harnesses, or vehicle restraints if applicable;</li><li>A <a href="https://www.avma.org/resources/pet-owners/emergencycare/pet-first-aid-supplies-checklist" target="_blank">pet first aid kit</a>;</li><li>A sturdy carrier or crate for each cat or dog. In addition to easing transport, these may serve as your pet's most familiar or safe space in an unfamiliar environment;</li><li>A favorite toy and/or blanket;</li><li>If your pet is prone to anxiety or stress, the American Kennel Club suggests adding <a href="https://www.akc.org/expert-advice/home-living/create-emergency-evacuation-plan-dog/" target="_blank" rel="noopener noreferrer">stress-relieving items</a> like an anxiety vest or calming sprays.</li></ul><p>In the not-unlikely event that you and your pet have to shelter in different places, your kit should also include:</p><ul><li>Detailed information including contact information for you, your vet, and other emergency contacts;</li><li>A list with phone numbers and addresses of potential destinations, including pet-friendly hotels and emergency boarding facilities near your planned evacuation routes, plus friends or relatives in other areas who might be willing to host you or your pet;</li><li>Medical information including vaccine records and a current rabies vaccination tag;</li><li>Feeding notes including portions and sizes in case you need to leave your pet in someone else's care;</li><li>A photo of you and your pet for identification purposes.</li></ul>5. Be Ready to Evacuate at Any Time
<p>It's always wise to be prepared, but stay especially vigilant in high-risk periods during fire or hurricane season. Practice evacuating at different times of day. Make sure your grab-and-go kit is up to date and in a convenient location, and keep leashes and carriers by the exit door. You might even stow a thick pillowcase under your bed for middle-of-the-night, dash-out emergencies when you don't have time to coax an anxious pet into a carrier. If forecasters warn of potential wildfire, a hurricane, or other dangerous conditions, bring outdoor pets inside so you can keep a close eye on them.</p><p>As with any emergency, the key is to be prepared. As the American Kennel Club points out, "If you panic, it will agitate your dog. Therefore, <a href="https://www.akc.org/expert-advice/home-living/create-emergency-evacuation-plan-dog/" target="_blank" rel="noopener noreferrer">pet disaster preparedness</a> will not only reduce your anxiety but will help reduce your pet's anxiety too."</p>Evacuating Horses and Other Farm Animals
<p>The same basic principles apply for evacuating horses and most other livestock. Provide each with some form of identification. Ensure that adequate food, water, and medicine are available. And develop a clear plan on where to go and how to get there.</p><p>Sheltering and transporting farm animals requires careful coordination, from identifying potential shelter space at fairgrounds, racetracks, or pastures, to ensuring enough space is available in vehicles and trailers – not to mention handlers and drivers on hand to support the effort.</p><p>For most farm animals, the Red Cross advises that you consider precautionary evacuation when a threat seems imminent but evacuation orders haven't yet been announced. The American Veterinary Medical Association has <a href="https://www.avma.org/resources/pet-owners/emergencycare/large-animals-and-livestock-disasters" target="_blank">more information</a>.</p>Bottom Line: If You Need to Evacuate, So Do Your Pets
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