Insect Population Dwindling in Louisiana Marshlands Four Years After BP Blowout

Louisiana State University entomologist Linda Hooper-Bui has been studying the impact of the BP oil spill on insects and spiders for almost four years. She started her study shortly after the Macondo well blew out on April 20, 2010, before any oil washed up on shore. Her work documents the dwindling of the insect population in areas directly hit with the oil.

On April 9th, she returned to Bay Jimmy and Bay Baptiste, areas that were heavily impacted by the oil spill in Plaquemines Parish, Louisiana.

“Insects are the basis of the food chain. They are like nature's Twinkies,” Hooper-Bui says.

Her studies also monitor fish and birds, since they eat insects. She sweeps areas designated for her study by walking back and forth waving a net, catching whatever insects are present.  She then empties the net into alcohol, preserving the insects for testing. She takes note of the wind speed and temperature at each location and collects a sample of sediment to be tested for hydrocarbons.

Weathered oil found coating the surface of the marsh in Bay Baptiste, Louisiana on April 9, 2014. ©2014 Julie Dermansky

Back in the lab, Hooper-Bui sorts insects by species. She sends some out for testing and stores the rest so other scientists can study them. The results of the test reveal the nutrients found in them, including carbon, nitrogen and sulfur. Knowing what the insects are eating helps her evaluate changes in the environment. She compares the data from sites that were oiled to those that were not.

Linda Hooper-Bui holds a bag containing insects collected in Bay Jimmy, one of the areas hardest hit by the BP oil spill. ©2014 Julie Dermansky

Hooper-Bui makes it clear that she is an independent scientist collaborating with other scientists at other institutions. Her work is not part of any government studies or studies subsidized by BP. Funding for her work has come from competitive grants from the National Science Foundation, the Northern Gulf Institute, the Gulf of Mexico Research Initiative and two grants from LSU. She believes being a scientist is a civic duty, and will not allow her work to be compromised.

Hooper-Bui's first peer-reviewed reports should be available by this summer, but she has been sharing her observations with interested parties all along. She hopes her work will be utilized by those who have to deal with future spills and by those making policy decisions that involve the oil industry as well as locals who are still dealing directly with the aftermath of this disaster.

Since there are fewer insects and spiders for birds and fish to eat, she is seeing a decrease in other species' success.

“This is what happens when the ecosystem seems to be disrupted,” Hooper-Bui says.  Her studies show that not only does oil remain in the marsh in Plaquemines Parish, it is still emitting volatile aromatics. Preliminary results indicate the volatiles naphthalene and methylnaphthalene remain in the oil contaminated parts of the marsh, and could be responsible for the dramatic decline in insect population. Naphthalene is an insecticide, according to Hooper-Bui.

While standing on weathered oil on the shore of Bay Jimmy, Hooper-Bui told DeSmogBlog, “I am looking at how an environment rebuilds itself after a catastrophic disturbance. It is a chronic situation in the marsh, not an acute one because the oil is still here,” she notes. “The oil gets remobilized when storms hit, and when the tide is low and the temperature heats up, volatile compounds emit from the exposed weathered oil coating the surface.”

Weathered oil coats the surface on the marsh in Bay Jimmy, one of the areas hardest hit by the BP oil spill. ©2014 Julie Dermansky 

Hurricanes affect insects too, so weather factors into Hooper-Bui's data as well. She has been involved with research about storm effects on insect populations since 2009. Her earlier work gave her benchmark data on how insect populations are affected by storms. 

“A healthy environment will rebuild itself after a storm,” Hooper-Bui says. “We know that from Isaac – a compromised eco-system is of concern. The plants might look o.k. but the insects are constantly fumigated when the water is not on the marsh (due to north wind or low tides) and the temperatures are high  – when sediment is exposed – the volatile compounds come off the marsh and fumigate the insects and they die – we have results for three years to show that, in the field and in the lab.”

Critics of her studies claim there are no volatiles coming off the marsh. But Hooper-Bui stands by her findings.  

“We put cages with insects in them where the only interactions the caged insects had with the environment were with the air in the marsh – and they were dying in oiled areas and surviving in non-oiled areas. When the marsh's sediment is exposed and the temperature gets above 85 degrees Fahrenheit, the oil is being biologically degraded, the oil is releasing volatiles and is killing the insects.”

A report released by The National Wildlife Federation before the fourth anniversary of the BP disaster deals with 14 species higher up in the food chain than insects. On dolphins, the report cites the National Oceanic and Atmospheric Administration (NOAA) report that states, “NOAA researchers found strong evidence that the ill health of the dolphins in Louisiana’s Barataria Bay was related to oil exposure.”

And on tuna, “20% of larval fish could have been exposed to oil, with a potential reduction in future populations of about 4%. For a species already in peril, reductions in reproductive success and lower populations can be major impediments to recovery.”

The report goes on to cite a study co-authored by John Incardona, research toxicologist at NOAA. From the NWF report:

“A more recent study shows that a chemical in oil from the spill can cause irregular heartbeats in bluefin and yellowfin tuna that can lead to heart attacks, or even death. The effects are believed to be particularly problematic for fish embryos and larvae, as heartbeat changes could affect development of other organs. The researchers suggest that other vertebrate species in the Gulf of Mexico could have been similarly affected.”

BP refutes the report. BP spokesman Jason Ryan told UPI, “The National Wildlife Federation report is a piece of political advocacy, not science,” he said. “It cherry picks reports to support the organization’s agenda, often ignoring caveats in those reports or mischaracterizing their findings.”

However, BP has been criticized for claiming the company will make things right in their advertisements. BP’s ads stress they are committed to the Gulf and committed to America and that business is back to normal, yet BP continually objects to a claims settlement the company already signed off on. They have also been accused of acting as trolls on internet sites and spreading misinformation.

Linda Hooper-Bui checking sediment in Bay Jimmy, some of it mixed with weathered oil. ©2014 Julie Dermansky

Hooper-Bui explains, “Insects are important to study because they are the basis of the food chain – and because people don't care about them, I can manipulate them for my studies without upsetting anyone. Insects are like a canary in a coal mine,” she says. “There is a big problem when they start dying.”

To anyone who thinks the oil isn't still out there, Hooper-Bui says, “Come out here and I'll show you. It wasn't cleaned up.” 


Naphthalene borders on being a volatile and semi-volatile organic compound. But considered a semi-volatile compound or polynuclear aromatic (PNA). When in a pure state, its a solid at room temperature, but sublimates to a vapor fairly readily. Back in the day it was used as mothballs. Naphthalene is present in diesel fuel. Not so much, or at all, in gasoline. Naphthalene makes up about 1 to 2 percent of crude oil, maybe more maybe less.

Everything you wanted to know about naphthalene, but were affraid to ask:

So if we're talking about environmental sampling nomenclature, naphthanlene would not be considered “a volatile” per se.


I'm actually trying to help. Take the following with a grain of salt, since its been awhile since I did environmental work. And this is the comments section for crying out loud - accuracy can be plus or minus 100 percent.

There's environmental science and then there's environmental science nomenclature. It becomes important to distinguish the two when considering sample chain of custody. And for senstive sites the the gulf. Especially when you're talking about approved methods of sampling and analysis. I'm not addressing the issue of the presence of naphthalene. I'm talking about nomenclature and methods of sampling and analysis. Like I said, naphthalene falls in between volatile and semi-volatile.

For petroleum spill sites, constituents typically fall under TPH or total petroleum hydrocarbons, VOCs or sometimes BETX (volatile organic compounds or Benzene, Toluene, Xylene and Ethyl Benzene) and PAHs (polynuclear aromatic hydrocarbons). And other things like metals and whatnot. PAHs pretty much equals PNAs. Again its nomenclature.

Naphthalene probably falls into PAH category rather than VOCs in this case. I forgot - its been a long time. On the other hand, naphthalene may or may not fall under VOCs under sampling and analysis protocols, i.e. US EPA SW-846. It depends on what analysis is used to detect constituents in soil and sediments. So as you can see it gets confusing and depends on source of spill, what was spilled, whether state or feds have authority and what regulatory process the spill falls under.

Tip: google gulf oil spill sampling and analysis plan and analytical quality control and quality assurance plan. Who knows what will show up. I'm too lazy.

On a physical property basis alone naphthalene falls somewhere between volatile and semi-volatile. It does vaporize, but not as readily as a typical volatile like benzene. The best indicator of volatility of a constituent in the environment (soil and sediment) is vapor pressure - followed by soil partitioning coefficient - followed by henry's law coefficient. Focusing on vapor pressure alone (the ease of which a molecule goes to vapor). Here are some example constituents and respective vapor pressures (do your own checking this was a quick search):

Benzene: 94.4 mmHG 

Xylene(s): 8.3 mmHG

Naphthalene: 0.087 mmHG

This means that at what pressure does it take to vaporize the constituent. The higher the pressure the greater the potential for the constituent to be in a vaporous state. Benzene is much more volatile than Xylene and much much more than naphthalene.

Like I said before - naphthalene sublimates fairly readily by transitioning from solid to vapor rather than the usual solid to liquid to vapor. 

To conclude, it can become confusing fast. This is about nomenclature not the presence of a petroleum hydrocarbon.