posted Nov 11, 2010, 1:10 PM by Cesar Harada
posted Jun 17, 2010 3:39 PM by Li Yu [ updated Jun 17, 2010 3:56 PM by Cesar Harada ]
Spill’s Effects Underwater
Efforts are under way to keep the oil spill in the Gulf of Mexico from reaching birds, mammals and critical shoreline habitats, but some marine biologists worry about the effects of the oil slick and the use of chemical dispersants on life underwater. “Dispersants tend to be toxic in and of themselves but may be the lesser of two evils,” said Jacqueline Savitz, a senior scientist at Oceana, a nonprofit environmental group.
Dispersants on the Surface
Chemicals are being sprayed onto the slick by aircraft to speed up
the natural dispersion of oil. Dispersed oil is spread by waves and
wind in surface waters, where many marine animals live.
Dispersants at the leak
BP officials said they were injecting dispersants into the oil as it flows from the well. Engineers hope the chemical, though usually used on the water surface, will break up the oil before it rises. Though the full environmental impact is unknown, there is less biological life to affect at this depth.
Impact on Sea Life
Brown pelicans and other seabirds often dive into the oil because the slick makes the water look calmer. If they are coated in oil, they will be unable to regulate their temperatures, leading to hyperthermia.
Plankton, tiny immobile organisms at the base of the food chain, can be killed by chemically dispersed oil.
All four species of sea turtles in the gulf are threatened or endangered. Some have already washed up ashore, and with numbers already low, it would be harder to rebuild the population.
Dolphins, which often follow boats to play, have been following response crews, getting near the slicks.
Shrimp and other shellfish are more vulnerable to oil and chemical dispersants because they are stationary, while some adult fin fish populations may be mobile.
Fish larvae are most at risk. Bluefin tuna, now spawning near the spill, are of particular concern. The Gulf of Mexico is one of only two nurseries in the world for bluefin tuna.
Sperm whales, which spend most of their time diving for prey, may come up in the slick as they reach the surface to breathe.
Link : http://www.nytimes.com/interactive/2010/04/28/us/20100428-spill-map.html