War’s Oil Slick Threatens Gulf Wildlife

A spreading oil slick near Iran’s coast is exposing another cost of the war: the threat of lasting damage to marine life and fragile coastal habitats after the fighting ends.

Greenpeace reported Sept. 11 that satellite images showed pollution on the eastern side of the Strait of Hormuz expanding from approximately 200 to 400 square kilometers within one day—about 154 square miles. The organization identified the tanker Riesco as a possible source because its last recorded position was near the apparent origin of the spill. That connection remains an assessment rather than a confirmed finding.

The U.S. military said it destroyed five Iranian oil tankers, including the Riesco, on Tuesday, Sept. 8, following missile attacks on an American warship. It said crews were instructed to evacuate before the strikes. The attacks followed U.S. strikes against three tankers on Sept. 5; American officials described those vessels as part of a network financing Iran’s Revolutionary Guard.

Along southern Iran’s otherwise arid coastline, mangrove forests create distinctive pockets of life. The protected deltas of Rud-e-Gaz and Rud-e-Hara support two mangrove species, making these wetlands an important part of the region’s ecological landscape. Their vulnerability makes the movement of offshore pollution toward shore a serious concern.

Oil reaching these forests can coat exposed roots and interfere with the exchange of gases essential to tree survival. According to the National Oceanic and Atmospheric Administration, severe oil exposure can cause damage lasting years or decades. Cleanup is also difficult: dense roots restrict access, and poorly chosen recovery methods can further injure an already stressed habitat.

The latest slick adds to evidence of a broader environmental toll. University of South Florida researchers reported June 8 that oil pollution covered roughly four times as much area in the Persian Gulf during March 2026 as during March 2025. Their satellite analysis identified persistent leaks around oil infrastructure and sunken vessels, along with pollution associated with ships trapped in the region.

The study was undergoing peer review when the university announced its findings. Researchers also warned that hostilities were obstructing cleanup and on-site observations, complicating efforts to assess and contain the environmental damage.

The reported expansion of the latest slick is alarming, but it does not establish how much oil escaped or whether this particular spill has reached protected wetlands. Those unanswered questions will help determine the scale of the damage—and whether the war leaves coastal ecosystems struggling to recover long after the attacks stop.