Naomi McKinnon knew something was up, but she was not sure what. She went below deck for a minute, then rejoined her two crewmates on watch.
Then it hit her. From horizon to horizon, from stern to bow, the sea all around them was glowing as their 52-foot-long ketch passed south of the Indonesian island of Java on a moonless night.
“What the hell?” she recalled thinking.
What Ms. McKinnon and her six crewmates encountered in August 2019 was a swell of glowing seawater so bright and gargantuan in size that a satellite orbiting hundreds of miles overhead was able to see its shimmers. Last summer, a team of scientists reported on the satellite feat, which opened a window to one the planet’s most puzzling features. The bioluminescent seas appear to originate when trillions of tiny bacteria light up in unison.
Now, a researcher who authored that paper, Steven D. Miller, a satellite expert at Colorado State University, has chronicled how Ms. McKinnon and her crewmates used their own observations, cameras and bucket of seawater to verify the satellite findings — albeit unknowingly.
Late last year, after Ms. McKinnon learned of Dr. Miller’s research, she came forward, reluctantly. “I thought, ‘Maybe he doesn’t want to know,’” she recalled. “But his response was ‘Wow! You’re the first person to confirm this!’ He was so excited. I was really glad I reached out.”
Dr. Miller told of the sailboat’s corroboration of the spacecraft observations in the Proceedings of the National Academy of Sciences on Monday.
At the ocean’s surface, bioluminescence comes in two general types. The common one arises when churning waves or other movements stimulate microorganisms to glow. Many a nighttime beachgoer has seen the blue-green luminescence in breaking waves.
The other type — the kind the boat’s crew observed — is poorly understood and appears to exist free of mechanical stimulation. Its rarity makes the joint observations from both the satellite and the ship a major scoop for ocean science.
Dr. Johan Lemmens, a retired medical doctor from Southend-on-Sea, England, was circumnavigating the globe in the two-masted sailboat he owns and captains when the sighting occurred. He said he had never seen anything like it.
“Normal bioluminescence is when the waves light up or there’s a trail of light behind you,” Dr. Lemmens said. “You see that two or three times a year. This was different. The sea was lit, but the waves were black. That made it really eerie. It gave the idea that the light was coming from a deeper level.”
The crew lowered a bucket into the water and pulled up a sample that contained several pinpoints of light that glowed steadily until the water was stirred; then, the points suddenly went dark. That response, the new paper notes, is contrary to “normal” bioluminescence.
Ms. McKinnon said her first awareness of the glow came around 9 p.m. local time and that it intensified during the night, lasting until dawn. The satellite observations revealed that the glowing patch south of Java, Indonesia’s most populous island, persisted for at least 45 nights and grew to be larger in size than the collective areas of Vermont, New Hampshire, Massachusetts, Rhode Island and Connecticut.
Ms. McKinnon studied biochemistry in college and was a research assistant in a laboratory at the University of Sydney in Australia before learning on a sailing forum of the global circumnavigation and, at age 24, joining the voyagers. In her lab, she studied deadly marine venoms, including, for instance, those of box jellyfish, the toxins of which attack not only skin but the heart and nervous system.
Dr. Lemmens, who grew up in the Netherlands, said the circumnavigation was a celebration of his retirement. His ketch, Ganesha, named after a Hindu god of beginnings, carried a crew of seven.
Ms. McKinnon said that, after their sighting off Java, she did internet searches when in port but failed to learn much. Later, she entered medical school at the Australian National University and last fall was doing yet another search when she read about Dr. Miller’s satellite paper.
“I still had that question in my head,” she recalled. “What was it?”
Steven H. D. Haddock, an expert in bioluminescence at the Monterey Bay Aquarium Research Institute in California and a co-author of the satellite paper with Dr. Miller, said it was wonderfully fortuitous that “coverage of the original science reached sailors who reached back to us,” giving the team independent verification of the rare phenomenon.
Dr. Miller said
the observations by Ms. McKinnon and crew offer insights on a major enigma — how tiny organisms can influence whole seas.
“It’s one big coupled system,” Dr. Miller said of ocean currents and the atmosphere. “It’s important for us to understand how this basic level of the biosphere ties into that.”