A massive oil tanker that sank off the coast of China could affect marine life for decades, environmentalists and experts say.
The Iranian-owned Sanchi fell to the ocean floor Sunday, eight days after it collided with a Hong Kong-registered cargo ship, resulting in a toxic, fiery blaze that claimed the lives of 32 crew members.
The Sanchi sank Sunday after days engulfed in flames
Much of the oil may have evaporated, but what's left could impact marine life
China's State Oceanic Administration said several oil slicks have already been found, including one nearly 15 kilometers long (9.3 miles) and another covering an area of 58 square kilometers (22.4 square miles).
The 900 foot-long tanker was carrying 136,000 tons -- around 1 million barrels -- of ultra-light crude oil at the time of the collision. Environmentalists and officials are worried the oil on board and the fuel used to power the massive vessel could harm nearby aquatic life.
"The critical thing is to understand that when we put hydrocarbons into the oceans through events like this, it's going to affect a wide range of animals," said Jessica Meeuwig, a professor of biological sciences at the University of Western Australia.
Chinese Foreign Ministry spokesman Lu Kang said an investigation is already underway.
Water samples tested by the Chinese government showed a dangerously high petroleum concentration around the spill.
This could have a detrimental impact on marine life, including aquatic creatures and bacteria, according to Ma Jun, one of China's leading environmentalists.
"The collision site was within the area which considered to be one of the richest fishing grounds in China, the Zhoushan shipping ground," said Ma.
"We still need to keep an eye on how these contaminants might be carried by the ocean flow to have the impact on the fishing ground."
Squid spawning ground
According to Greenpeace, the Zhoushan area is a spawning ground for swordtip squids and bluefin leatherjackets, and during the winter is home to edible species like crabs and mackerel.
Previous incidents like Deepwater Horizon in the Gulf of Mexico have taught scientists that even if a spill is limited to a certain area or only immediately impacts certain species, it still has the possibility to affect entire ecosystems.
"The fact is that it goes all the way through the food chain," said Meeuwig.
The tanker was carrying condensate, an ultra-refined, highly volatile form of ultra light crude oil used to make products such as jet fuel.
Condensate, which is made up of a mixture of hydrocarbons, is lighter than the thick black crude oil associated with spills such as Exxon Valdez.
Condensate oil's high volatility means it evaporate more easily than heavier crudes. Much of the oil on board the Sanchi -- though it's unclear how much -- was likely consumed in the fiery blaze after the crash, environmentalists say.
Greenpeace said it is impossible to estimate how much of the condensate has burned off or evaporated. One modeling test cited by the environmental group suggested that less than 1% would remain on the sea surface five hours after the collision.
But the substance's volatility also explains why the tanker went up in flames so quickly, dooming the 30 Iranians and two Bangladeshi crew members on board the tanker, but not those aboard the other vessel involved in the collision.
According to the Chinese Foreign Ministry, the crew on board the Sanchi died within an hour of the accident "because of the large-scale deflagration and the toxic gas."