Stalled commercial ship traffic near the Strait of Hormuz is not only a threat to oil markets and global economies. Scientists warn that the idling vessels could unleash an invasive marine “super-spreader event” when trade resumes.
The Iran war has forced a halt to more than 1,500 vessels near the strategic waterway since the U.S.-Israel war on Iran began Feb. 28. Traffic has remained restricted for months as Washington and Tehran battle over control of the vital trade route, which carries one-fifth of the world’s oil and natural gas supply.
A new study produced by an international coalition of marine scientists warns that invasive marine organisms that have grown on the ships’ hulls could pose a significant threat to ecosystems across the globe when the ships reach their final destinations.
“If you had to sort of design a worst-case scenario, it would look a lot like this,” said Mario Tamburri, a professor at the University of Maryland Center for Environmental Science and the study’s lead author. “It’s a perfect storm.”
When ships are stationary for periods of days or weeks, the submerged parts of the vessel can become colonized by microbes, algae and other marine organisms. These organisms, when introduced to other ecosystems, can cause a wide array of consequences, from outcompeting native species to damaging infrastructure to introducing pathogens harmful to marine life and, sometimes, humans.
Researchers say the buildup of waterborne organisms can reach “rapid growth phase” after about 10 days. Cargo ships in most ports idle for less than two days on average. But many ships trapped near the Strait of Hormuz have remained there for months.
Compounding the threat is the fact that the ships became stalled at the start of spring, a season of growth and reproduction as waters warm. The sheer volume in the number of idle vessels – and their global routes – is especially concerning to researchers.
Taken together, the conditions have laid the groundwork for what scientists describe as an “immense international biosecurity threat.”
The environmental and economic costs of idling ships
The buildup of marine organisms on vessels, referred to as biofouling, can cause a wide array of problems not only for marine ecosystems but also for global shipping companies.
The growth can lead ships to have more drag as they move through the water, burning extra fuel and increasing exhaust emissions. According to the International Maritime Organization, biofouling wastes about 10% of all fuel used by the world’s shipping fleets. That has led operators to spend billions of dollars a year to mitigate the problem, using specialized coatings on the bottom of ships and specialized cleaning operations.
There are dozens of examples of invasive marine species hitchhiking on ships and threatening ecosystems around the globe.
One example the researchers highlight is the invasion of the Australasian barnacle Austrominius modestus to Western Europe during World War II. That invasion, which saw the new barnacle outcompete other native species, was linked to New Zealand ships being held in English ports while awaiting convoy escorts.
In the United States, the rope grass hydroid Garveia fransiscana was introduced to the Chesapeake Bay by commercial ships about a century ago. Since then, the organism, which is native to the Indo-Pacific, has caused major problems for infrastructure, mainly by clogging power plants’ cooling systems, Tamburri said.
“We’ve been working with a nuclear power plant locally to control and manage that fouling,” he said. “It’s costing millions of dollars per year to keep those cooling systems clear – and there’s lots of incidents like that.”
There’s also the potential for harm to marine life and humans.
Tamburri said there are diseases that infect things like shellfish that are suspected to have traveled along the hulls of ships. In the early 1990s, the pathogen Vibrio cholerae, which causes cholera, was discovered on five ships docked in U.S. ports along the Gulf of Mexico. Those ships had come from Latin America, which at the time was grappling with an outbreak of cholera.
After the discovery, the Food and Drug Administration recommended that the U.S. Coast Guard issue an advisory to shipping agents and captains requesting that ballast waters be exchanged on the high seas before ships entered U.S. ports.
Is the U.S. at risk?
There are several aspects to the disruption in the Strait of Hormuz that make it unprecedented, at least in modern history, Tamburri said.
The sheer number of ships − study authors cite at least 1,500 vessels − idled near the trade route and the length of time involved are just the beginning.
Tamburri said the organisms that thrive in the Middle East waters, such as the Strait of Hormuz, Gulf of Oman and Persian Gulf, are adaptable and especially resilient as the waters experience extreme seasonal changes. The Persian Gulf, for example, can reach 95 degrees in the summer and 60 degrees in the winter.
“Those organisms can withstand extremes,” Tamburri said. “They’re tolerant organisms, which makes them good candidates for invasions when they go to a new location.”
The areas most at risk are those nearby with similar conditions, such as high salinity and high temperatures. Southeast Asia and ports across India are at greater risk than most other locations, Tamburri said, especially international hubs for commercial shipping like Singapore.
The United States and North America in general are at a lower risk because of their distance and lower levels of salinity, Tamburri said.
“They’re not at zero risk by any means,” he said, adding that ports along the Gulf Coast are of particular concern because of their relatively high temperatures.
What can be done now?
Researchers recommend that operators and shipping companies conduct in-water cleanings to remove some of the buildup, citing the risk to ecosystems globally and the higher fuel costs.
But that scenario is unlikely for most ships “given the urgency of evacuating stranded seafarers and restoring shipping movements,” the study says. The researchers also cite limited capacity and constraints to operations aimed at cleaning hundreds of large commercial vessels.
Ports also are not expected to have the resources to conduct large-scale cleaning operations and will likely prioritize clearing bottlenecks, the study says.
Given these challenges, the researchers recommend that crews estimate the buildup of marine organisms before departing so authorities can evaluate risks. They also recommend that nearby ports monitor for early detection using low-cost, rapid assessments.
The researchers also call for governments, the maritime industry and others to strengthen biofouling management. “While the human and economic consequences of events like the war in the Middle East will always remain the highest priority, ecological impacts cannot be overlooked,” the study says.
Looking ahead, Tamburri said, the risks from biofouling are expected to only increase as climate change leads to warmer ocean temperatures.
“There could be areas where native organisms are on the edge of what they can tolerate because they’re not adapted to warmer waters,” he said. “Now perhaps these invaders have a better chance of colonizing and outcompeting the native species.”
Christopher Cann is a national reporter for USA TODAY. Reach him by email at ccann@usatoday.com.
This article originally appeared on USA TODAY: Iran war could unleash a marine ‘super-spreader event’
