What Happens to Shipping Containers Lost at Sea?
The stricken Costa Concordia cruise liner could be upright again next week, nearly two years after she capsized on the rocky shore of the Tuscan island of Giglio.
The ship struck a rock and tumbled on its side on Jan. 13, 2012, after captain Francesco Schettino allegedly drove it on an unauthorized route too close to shore, ripping a huge gash in the hull. More than 4,200 people were aboard, and 32 people died.
Weather permitting, the 114,500-ton ship will be raised next week. The $800-million project is considered to be one of the largest, most expensive and most daunting salvage operation in history.
The project began with securing the rusting wreck, which is sitting on two spurs of rock just off land.
In order to prevent any slipping or sinking along the steep seabed, four submarine anchor blocks are fixed to the sea bottom between the center of the wreck and the coast.
Twelve retaining turrets were installed for use during the righting of the wreck. Jacks, individually controlled by computers and mounted on the tops of the turrets, have been attached to 24 chains (two per turret) that pass under the hull and are fixed to the port side of the wreck.
After it's been rotated, the wreck will rest on a false sea bottom. It consists of giant cement sacks used to fill the space between the two spurs of rock on which the ship rests.
Three large platforms and three smaller ones have been fixed into the granite ground by drilling 6-foot holes.
A crane has installed 15 refloating caissons on the side of the ship that's above water.
Filled with water, the caissons will help pull the ship upright.
To right the ship, jacks have been attached to the caissons.
The jacks will tighten several cables attached to the top of the caissons and to the platforms, which will be pulled seaward.
On the other side, cables attached to the land will ensure the ship does not slide off the platform.
“This is a very delicate phase, during which the forces involved have to be offset carefully to rotate the wreck without deforming the hull,” Titan said.
When the ship is upright, other caissons will be fixed to the other side of the hull to stabilize it.
At the end of the emptying process, the Concordia will be upright, although a section of about 60 feet will remain submerged.
Sandwiched between the caissons, the ship will be towed to an Italian port for dismantling in spring 2014.
Soon after it left the Port of Oakland, California, in February 2004, the shipping vessel Med Taipei hit a strong winter storm with violent 30-foot-high (9 meters) swells. Amid rolling waves, 15 shipping containers came loose and toppled overboard, sinking to the icy seafloor inside the Monterey Bay National Marine Sanctuary.
Just four months later, scientists surveying the seafloor with an underwater robot found one of those lost containers nearly 4,200 feet (1,300 m) below the surface. They turned their chance discovery into an opportunity to study how aquatic life reacts to deep-sea pollution.
Ninety percent of the world's goods are transported by ship, and inevitably hundreds, maybe thousands, of containers fall overboard each year. Lost containers have caused some strange objects from Legos to hockey gloves to wash ashore on beaches around the globe. The Med Taipei container was transporting 1,159 steel-belted car tires. But not all containers hold such innocuous goods. Some carry batteries, pesticides and industrial chemicals that could be toxic to marine life. The boxes themselves might even be made of hazardous materials. [Photos: Trash Litters Deep Seafloor]
Researchers from the Monterey Bay Aquarium Research Institute (MBARI) deployed a remotely operated vehicle, or ROV, to collect video footage and seafloor samples from the sunken container site in March 2011.
The container, which had barely corroded, seemed to have a mixed effect on the local marine environment. For some animals, the box acted like an artificial reef. Creatures like tubeworms, top snails and scallops readily fixed themselves to the container, but the diversity of animals was actually lower around the hard surface of the box than the muddy seafloor, the scientists found. Jutting out of an otherwise flat seafloor, the container seemed to alter local bottom currents and attract predators, which could affect the distribution of animals.
"We have only begun to characterize the potential long term impacts of a single container on a deep-sea community," MBARI researcher Josi Taylor said in a statement. "Although the effects of one container may seem small, the thousands of shipping containers lost on the seafloor each year could eventually become a significant source of pollution for deep-sea ecosystems."
The researchers say further monitoring should help them assess how these localized changes play out in the long-term and whether the container's toxicity will prevent future communities of animals from colonizing the site. The team is awaiting the results of samples from a follow-up ROV dive in December 2013 to study possible effects of the container's coating, MBARI officials said.
The findings were published this month in the Marine Pollution Bulletin.
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