Studies look at BP oil spill's effect on insects

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Studies look at BP oil spill's effect on insects

wwltv.com
Posted on March 22, 2012 at 12:34 PM

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A University of Houston ecologist says insects and spiders that live on marsh grass have rebounded. But a Louisiana State University entomologist says her more detailed study shows falling numbers for many kinds of bugs.

They agree that it's too soon to know the lasting effects of the oil on marsh ecosystems....
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One of the most dramatic changes is in the numbers of ants that live in the hollow stems of the marsh grass and scurry around outside it to forage. In oiled areas, their numbers have dropped steadily since the spill, Hooper-Bui said.

"This year we're hard-pressed to find ants in previously oiled areas," she said. It's usually easy to find them on chilly winter days because they stay inside. In January and February, she said, an hour's search by breaking stems didn't turn up a single colony in areas where oil had landed, compared to six to eight colonies in areas not exposed to the oil.

In warm weather, sweeping a net through the stems picked up an average of 32 ants before the spill. That was down to about 10 in September 2010 in oiled areas. Last September, that average was down to 0.5 ants per net in oiled areas, compared to 17 in non-oiled areas.

Hooper-Bui said large-bodied spiders appear to have been hit harder than small spiders.

In the Atlantic salt marshes, Wimp said, some of the largest spiders are at the top of the Spartina ecosystem food chain. "It's pretty common for things at the top of the food chain to be most heavily impacted when you have some sort of disturbance," she said.

Full text:
http://www.wwltv.com/news/Studies-look-at-BP-oil-spills-effect-on-insects-143843466.html

 

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Re: Studies look at BP oil spill's effect on insects

Insects fall silent in oiled coastal marshes
By AMY WOLD
Advocate staff writer
April 24, 2013

Louisiana?s coastal marshes can be noisy places with insects buzzing and chirping constantly, but that?s no longer the case in some places.
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Preliminary results from field work and lab experiments point to two oil components ? naphthalene and methylnaphthlane ? to be at least part of an explanation for large declines in insect populations within oiled or previously oiled areas of coastal marsh, she said.

?We have results, good information, that these are increasing and that this is an emerging problem,? Hooper-Bui said of the two compounds.
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Some insects were disappearing that didn?t have much contact with sediment or water in the marsh so the researchers set up a field experiment. Crickets were placed in small cages with food and water and then floated in a cage on the marsh so the only contact they would have with the environment would be the air, she explained.

The crickets in the oiled areas died.

?It was something in the air that was killing them,? Hooper-Bui said.

That field work was followed by some laboratory experiments using sediment collected in 2011 and again, the crickets died.

More recently, the laboratory experiment was repeated for soil collected in
March 2013, and the crickets on that soil again died, she said.

There were other signs of something is wrong within the more than 100 insects and spiders the researchers examined. One example is the population decline of ants that live in the hollow stems of marsh grass starting in 2010.
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Since January, Hooper-Bui and fellow researchers have been looking for ant colonies in oiled sites but haven?t found any yet, she said. Currently, researchers are looking for mating flights of ants in these areas, but haven?t found any yet as well.
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Hooper-Bui said the next steps for researchers include trying to figure out concentrations of the compounds in the air since they already know the concentration in the sediment. That air concentration information is needed before researchers can examine possible impacts on other organisms, or even people.

However, Hooper-Bui said when they found the two suspected compounds, she did some research on the toxicology associated with them. She said they found symptoms of naphthalene poisoning match what some residents of south Louisiana have been complaining about including skin rashes, respiratory distress, digestive distress and more.
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Full text:
http://theadvocate.com/news/5792972-123/buzzing-of-insects-falls-silent

 

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Re: Studies look at BP oil spill's effect on insects

TOXICOLOGICAL PROFILE FOR NAPHTHALENE, 1-METHYLNAPHTHALENE, AND 2-METHYLNAPHTHALENE

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES Public Health Service Agency for Toxic Substances and Disease Registry​

August 2005


http://www.atsdr.cdc.gov/toxprofiles/tp67.pdf