The Middle East – and the Persian Gulf at its heart – have been hit by the war in Iran since late February. Mines were deployed throughout the Strait of Hormuzthe entrance to the Gulf, countless oil spills have spilled oil into its waters and missiles have fallen dangerously close to Iran’s only nuclear power plantrisking radiation infiltration from the coastal facility. Even before the current chaos began, the underappreciated treasures of the Gulf’s ecosystems were under severe pressure, scientists say. Now they fear that notable examples of evolution in action and potential genetic secrets to surviving climate change could be lost.
“These environments are on the edge,” says Kaveh Samimi-Namin, a marine biologist at the Naturalis Biodiversity Center in the Netherlands, who grew up in Iran. “Anything that happens that impacts the environment can really drive these animals, this biodiversity, off the cliff.” »
“A sea of contrasts”
On supporting science journalism
If you enjoy this article, please consider supporting our award-winning journalism by subscribe. By purchasing a subscription, you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
THE Gulf ecosystems are shaped by remarkable geology and geography, says Bernhard Riegl, a marine biologist at Nova Southeastern University in Florida who has worked in the Persian Gulf for more than 30 years.
Sandwiched between Iran and the Arabian Peninsula, the Gulf is geologically young; the shallowest areas have been underwater for only about 6,000 years, and the water mass as a whole is just the result of melting glaciers at the end of the epoch. last ice age. This means that its marine life is a novelty in the grand scheme of things. In fact, the corals are so young that they haven’t had time to build extensive reefs.
The Gulf is also a place of extreme life: its summers are hotits winters are cold and its waters are remarkably salty. Yet it is full of life. “The Gulf is often wrongly considered to be biologically poor due to its harsh environment,” says Mohammad Reza Shokri, a marine biologist at Shahid Beheshti University in Iran.
Take the corals: “If you put the corals from the Great Barrier Reef into the Gulf now, they will all be toast,” says Samimi-Namin. Yet in just a few thousand years, the corals that inhabit the Gulf have evolved to tolerate the hostile conditions.
With most tropical reefs expected to face Gulf-like conditions by 2100 – and already weakened by increasingly frequent marine heatwaves – make Gulf corals a source of valuable genetic information on resilience that could have implications for the rest of the world’s reefs. “It’s as if someone built a small laboratory to study how tropical biota should behave in really extreme climates,” says Riegl. “We have the gold of evolution left.”
A Sooty Gull nesting on an island in the Persian Gulf.
Karim Sahib/AFP via Getty Images
Of course, there aren’t just corals in the waters of the Gulf. Plots of seagrass meadows and mangrove forests border the coasts, as do the mudflats which serve as essential feeding sites for migratory birds. The Gulf is also home to some of the most charismatic species on the planet: hundreds of massive whale sharks were discovered in a seasonal aggregate in the middle of an oil field off the coast of Qatar in 2011, and investigations in 2019 and 2020 revealed the largest known herd of manatee-like dugongs.
The ecology of the Strait of Hormuz, where salt water enters the Gulf, is particularly astonishing, Riegl says. Its biodiversity, he says, is “just absolutely epic”. From there, the water flows north and west along the rugged coasts of Iran, then south and east along the shallower coast of the Arabian Peninsula. This slow counterclockwise flow, combined with the way the water increases in temperature and salinity as it passes through the Gulf, means that the Iranian side is home to milder conditions and higher biodiversity.
Even though Gulf species have endured incredible conditions, the stress has already taken its toll. “It’s a sea of contrasts,” Shokri says. “This duality – resilience and fragility – is what makes the Gulf both scientifically important and crucial for conservation. »
Feel the heat
The Gulf’s vulnerability has become increasingly evident over the three decades Riegl has studied it, due to three key factors, he says. The series of heat waves that began in the late 1990s was the most devastating. These successive events gradually overcame even the hardy corals of the Gulf; he estimates that 90 percent have bleached, which happens when stressed corals eject the symbiotic algae that live there, turning them white.
The region’s construction frenzy has been the second most devastating cause for marine ecosystems. Along the southern Gulf Coast in particular, natural shorelines have all but disappeared under infrastructure such as ports and sewage plants, massive development of artificial islands and more since he began visiting the region, Riegl says.
A satellite view of an oil tanker on fire in the Strait of Hormuz, March 18, 2026.
Gallo Images/Orbital Horizon/Copernicus Sentinel Data 2026
Then there is pollution, some of which comes from previous conflicts. For example, the first Gulf War saw crude oil oil spills totaling millions of barrels, much of it hardened into a substance called bitumen. “In some regions, the shores are mainly asphalted and covered with sand,” explains Riegl. “This pollution has still not disappeared.”
Worse still, the heat makes spilled oil more toxic, with some scientists estimating that the Gulf is the most polluted marine basin in the world. Among other damages, oil can essentially choke mangroves, interfere with the sense of smell of hawksbill and green turtles that guide their navigation, and prevent fish from breeding.
More recently, massive desalination plantswhich often act as power plants, have been dumping hot, fast-sinking brines, choking out life at the bottom of the Gulf, Riegl says. “It just sterilizes the seafloor; nothing really lives there.”
Currently, no one knows precisely how the Gulf’s ecosystems are faring amid the new conflict, Shokri says, even though satellite imagery has shown several oil spills since the attacks began earlier this year. Experts know that even if the attacks mainly target Iran, the consequences will not be limited to there. Oil follows the same counterclockwise current as everything else in the Gulf. “It’s just a little puddle; it’s all connected,” Riegl says.
The three experts emphasize that there is still time to safeguard these remarkable ecosystems. As a coral expert, Riegl notes that even with mass die-offs, corals remain. “We’ve had a decade of devastation, but there’s still something there,” he says. “They’re small, they’re beaten up, they’ve been through hell, but they’re still here.”