Seafloor container ecology
Thousands of shipping containers are lost from cargo vessels each year. Many of these containers eventually sink to the deep seafloor. In 2004, scientists at the Monterey Bay Aquarium Research Institute (MBARI) discovered a lost shipping container almost 1,300 meters (4,200 feet) below the surface of the Monterey Bay National Marine Sanctuary. In the first-ever survey of its kind, researchers from MBARI and the sanctuary recently described how deep-sea animal communities on and around the container differed from those in surrounding areas.
In February 2004, the cargo vessel Med Taipei was traveling southward along the California coast when severe winds and seas dislodged 24 shipping containers, 15 of which were lost within the boundaries of the Monterey Bay National Marine Sanctuary. Four months later, during a routine research dive using the remotely operated vehicle (ROV) Ventana, MBARI scientists discovered one of these containers on the seafloor.
In March 2011, a research team led by Andrew DeVogelaere of the sanctuary and Jim Barry of MBARI completed another ROV dive at the container. During this dive, they collected extensive video footage, as well as samples of seafloor sediment at various distances from the container. They then compared the animals found on the container, on the nearby seafloor, and on the surrounding seafloor out to 500 meters (a third of a mile) away from the container. In early May, 2014 they published their findings in the journal Marine Pollution Bulletin.
Josi Taylor, the lead author of the recent article, said that she was surprised to see how little the container had corroded in the seven years since it sank to the seafloor. Apparently, the near-freezing water and low oxygen concentrations in the deep sea slowed the processes that might degrade sunken containers in shallower water.
As expected, the hard surface of the container acted somewhat like a rocky reef, attracting animals such as tubeworms, scallops, snails, and tunicates. Such animals require hard surfaces on which to attach, and were not found on the muddy seafloor around the container. Surprisingly, several types of animals found on nearby rocky reefs, such as sponges, soft corals, and crinoids (a distant relative of sea stars), had not colonized the surface of the container.
The researchers speculate that some of these slow-growing animals might not have had enough time to colonize the container's surface. Another possible explanation is that some types of animals may be sensitive to the potentially toxic effects of corrosion-resistant coatings used on shipping containers. The team conducted a follow-up ROV dive in December 2013 to study possible effects of the container's coating. The samples from this dive are still being analyzed.
Read more at Monterey Bay Aquarium Research Institute.
Underwater shipping container image by Chad King via NOAA/MBARI.