Not far from the vessels stuck in the Persian Gulf lies an ecological wonder. The highly contested Strait of Hormuz is home to dolphins and the most diverse coral population in the region, an underwater world that scientists say could be in jeopardy as conflict swirls around it.
Despite Iran announcing a reopening of the strait during a temporary ceasefire, about 2,000 vessels remain trapped in the Gulf as of Friday morning, carrying a total of around 21 billion liters of oil. There have been at least 16 attacks on ships in the Persian Gulf and near the Strait of Hormuz since the war broke out.
Nina Noelle, a spokesperson from Greenpeace, an independent global campaigning network that focuses on environmental issues, told CNN that through continuous monitoring, the group’s researchers “regularly detect oil slicks in the region,” including one linked to the Iranian vessel Shahid Bagheri that was struck by a US warplane in early March.
According to the organization, the vessel is still leaking oil “near the Khuran Strait and poses a potential risk to nearby protected wetlands.” The Khuran Strait is a narrower passageway that runs north of the Strait of Hormuz.
The Strait of Hormuz’s geographical position makes it a crucial site not just politically but ecologically as well — it sits at a transition zone between the deep, cool Gulf of Oman and the shallow, warm Persian Gulf. Currents sweeping in from the Gulf of Oman carry nutrients and larvae that fuel plankton blooms and coral reefs, while deeper upwellings draw in reef fish and migratory whale sharks that pass through seasonally.
In more peaceful times, scuba diving and dolphin-watching in Musandam Governorate, a part of Oman that borders the strait, was a magnet for tourism. The strait provides nesting grounds for sea turtles, and the coast of Oman is home to the critically endangered and nonmigratory Arabian humpback whales, with dugongs and sea snakes in the surrounding waters.
As the conflict drags on, scientists are increasingly concerned about the impact of oil spills on animals in the region.
“Many of the compounds found in crude oil will target heart function and respiration,” said Martin Grosell, professor and chair of the department of marine biology and ecology at the University of Miami’s Rosenstiel School of Marine, Atmospheric and Earth Sciences. “Prolonged oil exposure will lead to an overexertion of the stress response, and that suppresses immune function, rendering animals more susceptible to infections and other types of environmental insults.”
Crude oil also disrupts animals’ nervous systems, Grosell added, impairing their senses and ability to navigate, process input, and properly orient themselves in their environment. This affects how they respond to predators and find prey, meaning harm to individual animals can cascade through the entire ecosystem.
What animals live in the strait?
The Strait of Hormuz, a narrow passage between Iran to the north and Oman and the United Arab Emirates to the south, sits at the mouth of the Persian Gulf. Aaron Bartholomew, a professor of biology at the American University of Sharjah in the UAE, who has conducted field research throughout the region, describes the strait as the ecological crown of the Gulf.
“The Strait of Hormuz is known for having the most diverse and some of the highest coral cover in all of the Gulf,” Bartholomew said. The richest concentrations sit on the Iranian side of the strait, as well as along parts of the southern Gulf coast. The coral reefs in the area have been heavily impacted by bleaching events linked to rising ocean temperatures, but they have endured while corals elsewhere have not.
Bartholomew explained that Gulf conditions push marine life to its physiological limits. “We have very, very hot temperatures during the summer and surprisingly cold temperatures in the winter,” he said. “We also have elevated salinity because of all the evaporation from the Gulf,” he added, referring to high concentrations of dissolved salts in the water that typically cause ecological harm.
In most of the world’s oceans, such extremes would be lethal to coral. Here, the conditions have produced “arguably the toughest corals in the world,” Bartholomew said. He said that the corals in the region are important for researchers who are actively studying them as a model for how they might survive the hotter, more volatile oceans that the human-fueled climate crisis will bring.
“Corals are the most biodiverse ecosystem in the oceans, and they support a wide variety of fish and invertebrate species,” Bartholomew added. “They’re certainly important for fisheries. They’re important for tourism as well.”
