The leading edge of the massive oil spill is expected to reach the Louisiana shore today, as government officials, BP and others rush to try to protect the fragile coastal marshlands from an ecological disaster.

National Significance

The event, which is feared could become worse than the Exxon Valdez spill, has been deemed a disaster of “national significance” and President Barack Obama has pledged to “use every single available resource” – including the military – to help fight the oil slick.

Relentless

Despite attempts to slow its advance by setting it on fire, on Thursday night, winds had blown the leading edge of the slick just three miles away from the mouth of the Mississippi Delta. The US Navy said it had sent 66,000 feet of inflatable boom and seven skimming systems to the disaster area. Another short-term solution reportedly being implemented was a plan to set up a bell-shaped device to catch the oil as rose to the surface from the well, before being pumped into container ships.

But none of these measures have managed to slow the spills relentless advance towards the coastline on which hundreds of species and people depend. If the inevitable happens and the oil begins to wash onto the coast, then there are many different areas that will feel its effects.

The Effects

While the effects on wildlife are often those reported first, there are many people who depend on the welfare on the wildlife for their own livelihoods.

The Human Angle

Shrimp and oyster industries in Louisiana are set to be hit hard, as oysters are filter feeders and cannot swim to escape the slick. The prime oyster-gathering season in Louisiana was supposed to start this weekend

A number of fisheries could suffer as a result of the spill. The Gulf menhaden fishery — a species harvested mostly for fish meal and fish oil — is America’s third largest and in some seasons its second largest

Menhaden are filter feeders and so they could be badly affected by the spill, as they pass tainted water through their filtering system. The season for Texas, Louisiana and Mississippi had only been open for a matter of weeks when the disaster struck.

Key Habitat

The Gulf of Mexico has become a key habitat for a number of species, some of which have already been affected with the spill in the ocean, but if the slick reaches land the number affected will increase greatly.

Bluefin Tuna

The northern Gulf of Mexico is a crucial spawning ground at this time of the year for the Atlantic population of bluefin tuna, which is critically endangered. Their eggs float near the surface and the larvae also stay near there after they first hatch. So, the spill has occurred at a critical time in their life-cycle.

For the Birds

Louisiana contains around 40 per cent of America’s wetlands. Many species are threatened if these become contaminated with the oil, including oystercatchers and plovers.

Other species at risk include Louisiana’s state bird, the brown pelican, which was only removed from the U.S. Endangered Species Act last year. They nest on barrier islands and feed near shore. Their breeding season has just started.

Turtles

Several species of sea turtles are currently moving through the Gulf, as their spring nesting seasons commences and they need to surface to breathe so the slick could cause significant damage to their population as they pass through the Gulf.

Life, Interrupted

It is not just the scale of the spill that means huge damage could be done to wildlife, but its timing at the beginning of many species’ breeding seasons. This could mean that the effects of the disaster will be felt for years to come, as an interrupted breeding season will pressure on any species population, and this effect will be exaggerated in those with already reduced numbers.

Historic

The scale of the disaster is expected to reach historic proportions. Of most concern is the possibility that it could be months before the leak can be fixed.

Mike Miller, who runs Safety Boss, a Canadian oil well fire fighting company said the only “sure-fire” way of stopping the leak would be to drill a new hole at an angle into the old one and pump in sealant. “But that’s going to take months,” he said.

Mr Miller said the spill “could be right up there, if not the biggest ever”. He said the 1989 Exxon Valdez disaster, in which a tanker spilt 11 million gallons of oil off Alaska, “is going to pale into insignificance in comparison to this as it goes on”.