For the first year and a half after it vanished on March 8, 2014, Malaysia Airlines Flight 370 represented an unprecedented kind of aviation mystery, one whose only clues were a set of cryptic electronic signals suggesting the plane had crashed in the Indian Ocean west of Australia. Sixteen months later, in July 2015, a piece of its right wing called a flaperon washed ashore on the French island of Réunion, on the other side of the ocean. Here at last was physical evidence that the plane and its 239 souls really had flown into the remote southern patch of ocean and crashed.
Better still, the flaperon carried with it evidence that may help locate the plane and solve the mystery once and for all: a population of gooseneck barnacles called Lepas anatifera. Like the rings of a tree, their shells contain a record of their life. Decode that information and it may be possible to trace their path on the flaperon backward to the impact site and the mystery would be solved. “We stumbled upon something that gave much more certainty about the whereabouts of the plane than we anticipated,” says David Griffin, who led a team of Australian government scientists tasked with solving the case.
The flaperon and its Lepas spurred a decade of fruitful worldwide research into a previously obscure organism and unlocked the creature’s potential to serve as a natural data logger in all kinds of investigations, from tracking “ghost nets” that endanger wildlife to finding missing boats and even investigating mysterious deaths. But as marine biologists applied their new knowledge to the case of the missing plane, they found that instead of resolving mysteries, the barnacles revealed new ones.
As someone who has been publicly obsessed with MH370 for a decade, I have spent a long time exploring the fine points of Lepas biology, most recently on my podcast. These are fascinating creatures. In their larval stage, they swim free as plankton throughout the world’s oceans. Then once they’re ready for adulthood, they start looking for a floating object to attach themselves to. Having found one, they explore it, looking for an ideal spot — they prefer a deep, shady location far from the waterline — and glue their heads in place, using fine, sievelike appendages to sweep food particles from the water. Because they evolved to settle on biodegradable material such as logs and clumps of seaweed, they grow quickly and can reach maturity in a matter of weeks. On man-made objects that don’t decay, Lepas can grow for years, forming dense mats of long-stalked barnacles that look like medusa’s writhing hairdo of snakes.
Since Lepas tends to colonize any floating object, scientists say the oldest barnacles on it will reflect the total amount of time that object has spent in the ocean, often within the first weeks of its entering the water. “Assuming they have enough food and the temperature is good, barnacles will follow a steady growth progression,” says Cynthia Venn, a professor of environmental science at Bloomsburg University who studied Lepas barnacles growing on buoys in the Pacific Ocean.
Scott Bryan, a researcher at Queensland University of Technology in Australia, has studied how Lepas and other marine organisms settle on pieces of pumice that have been ejected into the ocean by volcanic explosions. Because the pumice starts out molten hot, and hence sterile, it offers a blank slate of sorts for biologists to study how the populations of organisms on floating debris change over time. “We find biological recruitment to be very quick, beginning within about two weeks,” Bryan told me. “Goose barnacles are one of the first colonizers.”
Once they settle, these populations are pretty robust. Although they do have predators on the open sea, such as sea turtles and nudibranchs, a kind of marine invertebrate, researchers say the barnacles generally get completely wiped out only if their host is washed ashore, where they will dry out and be picked clean by scavengers. “If there is nothing older than two months growing on it, we would interpret this to mean the pumice had not been floating in the ocean for more than three months,” Bryan says, allowing a margin of a few weeks for the organisms to become attached.
Scientists can tell the oldest and newest barnacles apart by measuring their size, which correlates with the length of time the animal has been growing on an object. This can be combined with “drift modeling,” which uses historical data about the drift paths of research buoys to create probabilistic estimates of a floating object’s origins. Martin Stelfox, founder of the Olive Ridley Project, a sea-turtle conservation program, has used Lepas barnacles to figure out where wildlife-ensnaring fishing gear has drifted from. “It’s a fairly reliable way to give you an idea of how long that gear has been drifting,” he says. “We can then use that age estimate to plug into things like drifting current models and start to backtrack to where potentially this gear may have come from.”
What researchers didn’t know back in 2015 was what a six-, 12-, or 18-month-old barnacle in the subtropical Indian Ocean would look like. In the years following the flaperon’s discovery, researchers tried growing barnacles in the lab and on buoys at sea and found that Lepas grows at different rates and winds up at different sizes depending on the temperature of the water and how much there is to eat. One team that looked at how Lepas grew in the cold waters of the Humboldt Current off the coast of Chile found that, after three months, the Lepas had stopped growing, at about 20 millimeters in length. Another studied a related species growing in the warmer waters of southeastern Australia and found they had gotten as large as 48 millimeters in as little as a month.
Conditions in the waters where the flaperon floated seem to lie somewhere in between. In 2020, Stelfox and his colleagues published the results of an experiment in which they had grown Lepas on buoys in the Maldives. They found that after 105 days of growth, or three and a half months, the largest of the shells was 35 millimeters — very close to the size of the biggest barnacle on the flaperon. The waters the buoys floated in are similar to those the flaperon would have crossed in reaching Réunion: the South Equatorial Current, the dominant east-to-west current spanning the latitude between northern Australia and Madagascar. So the growth patterns should be similar. Stelfox feels that when he stopped his experiment, the barnacles were continuing to grow and could have gotten as big as 50 millimeters if he had let them. “On personal observations, some of the barnacles we’ve seen in the Maldives were much bigger than the ones in our experiment,” he says.
It isn’t just the size of the shell that tells a story but also its chemical composition, which varies depending on the temperature of the water the Lepas is floating in when it lays down a given layer. This technique has been applied to the flaperon’s barnacles several times over the past decade. In the most recent study, published last year, a team led by Kuwait University researcher Nasser Al-Qattan analyzed a barnacle shell provided by the French authorities. The shell was relatively small, about 25 millimeters, which meant it was “only several months in age,” according to the study. Its chemistry indicated the creature had started growing in relatively warm water of 80 degrees before drifting into cooler water of around 75 degrees. “Its recorded drift reveals that the MH370 flaperon likely spent its last several months west of longitude 70°E and within 1,500 km of Réunion Island,” the researchers concluded. That’s over 1,000 miles from the MH370 search zone.
In other words, the specimen shared by the French was too young for Al-Qattan’s team to trace the flaperon’s path all the way back to the plane’s presumed impact site west of Perth, Australia. The French authorities had recovered larger specimens from the flaperon, the largest being 36 millimeters, but they hadn’t seen fit to share them with outside researchers. “Only partial drift reconstructions are possible until the largest, oldest barnacles are released for study by the French government,” Al-Qattan’s team noted.
But there’s reason to doubt that even a 36-millimeter barnacle would be old enough to track the flaperon back to the presumed impact site. Stelfox grew 35-millimeter barnacles in a similar patch of ocean in just 105 days. If one assumes the flaperon’s barnacles grew at an approximately similar rate, then the size of the flaperon’s barnacles suggest that it floated in the Indian Ocean for no more than about four months, not the 16 months that elapsed between the crash and the flaperon’s discovery.
That gap in the data — a yearlong interval between the plane crash and the start of barnacle growth — might be merely puzzling were it observed on the flaperon alone. But the entirety of the MH370 debris recovered so far displays this anomaly. Of the three dozen or so pieces of the plane that have been collected, not a single one has marine life on it that matches what you would expect to see if, as with the pumice Bryan studies, the debris had spent 16 months steadily gathering marine life from the waters it had traveled through.
One piece, a fragment of a closet door from inside the cabin, was found “heavily colonised by the Lepas anatifera barnacle,” according to an official report, but of the nearly 400 specimens recovered, the largest were just 20 millimeters long, implying an age of only “45 to 50 days.”
Another piece came ashore at Mossel Bay in South Africa and was photographed by a passerby who let the object wash back out to sea; it was rediscovered three months later just a few hundred yards away, having been stripped clean in the meantime. Based on my own image analysis of the original photograph, the largest barnacle appears to be about 25 millimeters, implying a time adrift of no more than several months.
There are other mysteries surrounding the debris as well. When French scientists took the flaperon from Réunion to a test facility in Toulouse, they put it in a tank to see how it floated. They found the slab-shaped flaperon floated at an angle, with one of its long edges sticking up high out of the water, where it’s physically impossible for Lepas to grow. Yet this edge was thickly settled with a healthy Lepas population. The apparent contradiction baffled the first French scientist who studied it and remains unexplained to this day. The edge had to be underwater, says Williams College invertebrate biologist Jim Carlton, “because it has Lepas on it. Lepas don’t lie.”
Another problem was that Australian investigators couldn’t get their drift modeling to work. The piece that washed up in Mossel Bay was hundreds of miles farther south than the models predicted it could have reached in its time afloat. That’s “something that is simply too hard for any present-day model to convincingly explain,” David Griffin, the principal research scientist at the Australian government’s Commonwealth Scientific and Industrial Research Organisation, told an interviewer in 2017 and confirmed to me this week.
The CSIRO worked hard to understand how the flaperon could have drifted to Réunion, believing that if their drift model were precise enough, it would help them identify exactly where the plane had crashed. After multiple attempts to refine their data by studying how replicas floated in the ocean under various wind and wave conditions, they could get it to match the flaperon’s landfall on Réunion after 16 months only if it had floated high enough in the water to be pushed by the wind. But this would have left the Lepas on the trailing edge high and dry, which experts say is impossible.
These mysteries are still just part of a host of paradoxes attending the disappearance of MH370. No one has yet come up with a reasonable explanation, for instance, as to how or why the satellite communications system that generated the pings officials used to define the search area in the remote southern Indian Ocean turned off. Two companies spent four years searching 93,000 square miles of seabed using towed sonar arrays and a fleet of underwater drones. Australian search officials admit they can’t explain why they came up empty, having stated that upon completion of the yearslong seabed search, “prospective areas for locating the aircraft wreckage, based on all the analysis to date, would be exhausted.”
Taken together, this swarm of paradoxes surrounding both the satellite data and the debris suggests that the authorities’ understanding of the case is badly flawed and that, if they have a sincere interest in solving it, they need to revisit their assumptions about what could have happened on that night ten years ago. “After a failed search, you have to recalibrate,” says Todd Humphreys, a professor of aeronautical engineering at the University of Texas at Austin. “Sometimes you preclude the possibility of even looking for evidence because you have very strong priors against it. I think by this point, we’ve been pushed into a corner where we do need to revisit those priors.”
