It had been gushing black goo for months, but the well that has spilled millions of liters of oil into the Gulf of Mexico was finally capped on September 19 2010.

The federal government’s point man on the disaster, Thad Allen, was quoted as saying the well is “effectively dead” and that it poses no further threat to the Gulf.

Sure, oil is no longer seeping from the well that sits on the ocean floor, 35,050 feet below the surface. But what about the 780 million liters of oil spewed out during the time the well wasn’t capped? Some of this has already been cleaned through the use of dispersants and burning, but much more is lying in wait below the ocean’s surface at all levels of the water column.

The explosion of the Deep Water Horizon rig on April 20 2010 killed 11 workers and led to the worst offshore oil spill in U.S history, causing serious, lasting damage to the surrounding environment.

“There’s been upwards of 5,000 birds and animals that they’ve counted that have been killed,” says Dr. Brenda Murphy, an associate professor in the Contemporary Studies Department at Laurier Brantford. Murphy has her Ph.D. in geography, and is an expert on environmental risks and disasters. “Of course there’s been more then that, [but] that’s just what they’ve counted.”

“There’s been impacts on the commercial fishing fleet, the recreational fishing, the tourism industry, so the hotels and the bars and everything that’s associated with that,” says Murphy.

Since so much of the oil still lies beneath the ocean’s surface, it’s hard to tell what the exact, permanent impacts of that will be or how badly the Gulf has been affected.

“I don’t think we’ll completely understand that for weeks, months, years,” says Murphy.

At the time of the spill, many animals that call the Gulf home were entering their period of hatching and rearing. Experts are also still unaware of the affects on the bodies of the workers involved in the cleanup of the toxic, carcinogenic crude oil. Murphy is cautious to speculate.

“Those are the kinds of things you don’t know right away,” says Murphy, “It could be two years, five years, ten years. It depends on the life cycle of that particular species.”

With so many things still unknown, it’s hard to tell what the ultimate impact of this oil spill will be, but one thing is known: the well spewed oil into the Gulf for five months and during those fives months, impacts were created that will be felt by the surrounding communities for generations to come.