Scientific American has some answers. (All bulleted items are quotes from the SA article.)
- "If the [oil] mousse gets into the marshes, it can last a real long time," says environmental chemist Jeffrey Short of environmental group Oceana, who has studied the aftereffects of the Exxon Valdez spill. "Once there's no oxygen, it doesn't break down fast at all; it's a long-term toxic reservoir."
- There is no cure. "The only way to remove it is mechanically, and that will destroy further the whole habitat," says marine biologist Héctor Guzmán of the Smithsonian Tropical Research Institute (STRI) in Panama, who is part of a team that conducted a long-term study of the impacts of the Panama oil spill in 1986.
- The toxic compounds in oil vary, but largely fall in the group known to chemists as polycyclic aromatic hydrocarbons (PAHs), such as napthalenes, benzene, toluene and xylenes. All are known human carcinogens with other health effects for humans, animals and plants. "These hydrocarbons are particularly relevant if inhaled or ingested," says environmental toxicologist Ronald Kendall of Texas Tech University. "In the bodies of organisms such as mammals or birds, these aromatic hydrocarbons can be transformed into even more toxic products, which can affect DNA." In other words, the effects of the oil spill will linger in the genetics of Gulf coast animals long after the spill is gone, resulting in mutations that could lead to problems ranging from reduced fertility to cancer.
- In essence, PAHs act as catalysts to shovel energy from the sunlight into oxygen molecules, shifting them into a more reactive form and thereby oxidizing living cells. If oxygen naturally existed in that state "the whole Earth would burn up," notes Short. That's bad news for the millions of translucent sea creatures out there—zooplankton—and could ultimately end up having cascading effects up the food chain. "If you start removing pieces of this big food web out there, what's going to happen?" [marine biologist Thomas] Shirley asks. "We don't really know but probably not good things."
- ... spring is breeding season for species ranging from migratory birds to sea turtles, all congregating along the Gulf shore. "This is the time of year for larvae," Shirley notes, meaning that entire generations of short-lived species such as shrimp or crabs may disappear. "It's going to take immigration to replace some of those lost-year classes for things to get back to the level they were."
- ...it's when the oil gets into the marshes that the effects really start to accumulate. "That's your nurseries," Kendall notes, for species ranging from fish to birds. Adds Short: "It sets the stage for impacts from embryo toxicity. It gets into the developing eggs and induces aberrations in development. Even the smallest aberration in the field is lethal.... These marshes are important nursery areas for pretty much everything."
- But "once the oil, because of high tides or high winds, gets into the coastal wetland, it gets trapped in the sediment," notes STRI's Guzmán. "Then for decades you continue to see oil coming back out, this chronic pollution." ...The most important task is stopping the oil from spilling—a prospect that remains out of reach nearly a month after it began gushing from BP's deep water well in the Gulf of Mexico.
NDTV, the source of the video, is an South Asian Indian broadcaster.