Oil slicks seen from space: the devastating impact of ship collisions on the Gulf’s fragile ecosystems | Strait of Hormuz

TThe vast dark sheets of the Strait of Hormuz are visible from space. Throughout October, oil tankers were hit by missiles or sea mines in the waterway and spilled crude into the sea. Pollution spread across the Gulf, contaminating coastlines and threatening lasting damage to marine ecosystems that are home to dolphins, sea turtles and countless species of fish.

Eight months after the start of the U.S.-Iran war, one of the world’s busiest oil transportation routes has become a battlefield and the center of a growing environmental disaster.

The naval blockade of the strait has made it almost impossible to document the pollution from the ground. But analysis of satellite images, combined with testimony from environmental experts and marine biologists, can help paint a picture.

Ecosystem in danger

The Strait of Hormuz, the only maritime passage between the Gulf and the Arabian Sea, is home to a rich but fragile marine environment, including coral reefs, mangrove forests and seagrass meadows that support rich marine life.

It plays a vital role in the circulation of water and nutrients and serves as a migration route for marine mammals. Even in peacetime, its ecosystems face increasing pressure from shipping, oil extraction and coastal development.

Oil can coat birds’ feathers, making it difficult for them to float and find food. It can cover the roots of mangroves, preventing the trees from absorbing oxygen and potentially killing them.

Bernhard Riegl, a marine biologist at Nova Southeastern University in Florida who has studied the Gulf for more than 30 years, warned that war could cause lasting damage to its confined waters, already under severe pressure from the climate crisis.

“Because the Gulf is shallow and summer is the least windy time of year, atmospheric heat quickly turns into ocean heat. This heat kills corals, algae and fish. There is no cold, deep water that could mix and buffer this heat,” Riegl said.

“Everyone knows that oil in water is not good. The potential for further damage is great. There is no such thing as ‘clean war’. Neither for the unlucky humans who find themselves drawn into it, nor for the unfortunate environment in which the conflict takes place.”

Strikes and spills

Since the war began on February 28, Greenpeace has identified more than 500 cases of oil spills through satellite monitoring of the Gulf, the Strait of Hormuz and the Arabian Sea. The findings include major spills linked to attacks on ships, as well as others detected at the time of collisions but whose origins could not be confirmed.

“Adding up the daily mapped footprints (of spills) we get a cumulative total of around 20,000 square kilometres, almost the size of Wales,” said Nina Noelle, Greenpeace expert on environmental disaster relief.

More than 133 attacks on oil tankers have taken place since the start of the conflict, according to Greenpeace. October was the worst month, with more than 30 attacks confirmed or reported in the Strait of Hormuz and surrounding waters, according to the Washington Institute for Near East Policy. The attacks continued into November.

Among the most polluting attacks in October was that of the supertanker Gem No 2, off the coast of the United Arab Emirates, which left a slick extending over 35 km. A satellite image dated October 19 shows a huge black spot moving in the clear waters off Umm Al Quwain.

Greenpeace estimates that an attack on an oil tanker in early June caused a slick off the coast of Oman that covered more than 600 km² (230 square miles) at its peak. Two Iranian navy ships hit in March continued to spill oil for months, said Wim Zwijnenburg, an environmental researcher at the Dutch peace organization Pax.

The attack on the Minoan Pioneer, flying the Liberian flag, on August 3, is also linked to a major oil spill.

Oil pollution has reached several coasts since the start of the war. In March, a slick from the Shahid Bagheri was detected near the Hara mangroves. In April, pollution threatened the protected Shidvar Island, home to coral reefs, seabirds and turtles. Oil was also reported on Qeshm Island in August, near important fishing grounds and turtle nesting sites.

Satellite images also show slicks near Oman’s Musandam National Park and Iran’s Minab River Delta, two areas rich in wildlife. Musandam is home to coral reefs and seabird breeding areas, while the Minab Delta is home to mudflats and protected mangrove forests.

Environmental organizations continue to analyze satellite images but warn that the extent of the damage cannot be established without on-the-ground investigations, which remain extremely difficult. Some researchers and environmentalists contacted for comment in Iran and Gulf countries said national authorities had asked them not to speak publicly about the environmental damage caused by the war.

Establishing responsibility is not simple, but Iran’s Islamic Revolutionary Guard Corps (IRGC) has been blamed for most of the attacks. U.S. forces have also targeted oil tankers, neutralizing Iranian ships that attempted to breach a U.S. naval blockade and striking others in response to Iranian missile attacks on U.S. warships.

According to a report in the Wall Street Journal, the largest oil spill was caused by a strike by the United Arab Emirates Air Force on oil storage tanks on Lavan Island. The strikes resulted in a spill of crude oil into the Gulf and affected coastal areas, including the neighboring nature reserves of Shidvar Island.

The damage to come

In some cases, countries bordering the strait have responded to the spills. After the Gem No 2 attack, for example, the UAE closed beaches, launched a major cleanup and monitored its desalination plants. Authorities announced on October 30 that the leak had been stopped and that pollution was decreasing.

In Oman, divers and equipment were deployed to a damaged vessel and crews cleaned up oil from 7 miles of coastline near the Hallaniyat Islands.

But the broader environmental damage could prove much harder to contain. “Oil could remain trapped in sediments, shorelines and mangrove roots long after the slicks disappear, damaging marine food chains and threatening coastal communities dependent on fishing,” Noelle said.

Contamination can affect organisms ranging from small invertebrates to fish, birds and turtles. “Mangroves and coral reefs can take decades to recover, especially when oil persists in the sediments,” she added. “Repeated spills, like those from the Strait of Hormuz, risk worsening the damage. »

Riegl said the aftermath of the 1980s Iran-Iraq War and the first Gulf War, when tankers, loading facilities and oil fields were targeted, provided evidence of the lasting impact of large-scale oil pollution on Gulf ecosystems.

A 2020 study traced widespread tar deposition – the thick, sticky residue left by the breakdown of crude oil – on Qatari beaches to the Gulf War. A 2022 study found that sediments on Saudi Arabia’s Abu Ali Island were still contaminated by oil from the 1983 to 1985 Nowruz spills during the Iran-Iraq War, which collectively dumped 80 million gallons of crude into the sea.

Riegl said: “Any organism that has to dig into the beaches (affected by spills), such as sea turtles when nesting, will encounter the contaminated strata and adverse effects can be expected. Burrowing organisms like ghost crabs will continue to bring contaminated materials to the surface.

“Clearly, the effects of large-scale oil pollution remain detectable for decades – so this is a generational problem. We could really lose something irreplaceable.”