Unlock the Editor’s Digest for free
Roula Khalaf, Editor of the FT, selects her favourite stories in this weekly newsletter.
It’s one of the most magical phenomena in nature — night-time bioluminescence, an unearthly blue sparkle that illuminates breaking waves and smears twinkling light across the shore, as if all the stars in the universe had been condensed into a celestial paste.
But where an untrained eye enjoys an enchanting light show, scientist Joaquim Goes sees an alarming and mysterious organism. It’s one he has chronicled for two and a half decades and whose extraordinary rise in the Arabian Sea, his research has found, is linked to climate change.
“It’s beautiful to see on the surface, but the sad thing is people do not know what is going on below,” says Goes, a research professor at Columbia University’s Climate School. “This organism is telling us a story, that things are changing.”
Noctiluca scintillans, or “sea sparkle”, has two faces. While it bedazzles in the dark, it’s responsible for a reeking green carpet of algae by day. Every year, the stuff covers an area the size of 1.8mn square kilometres in the Arabian Sea, nearly three times the size of Texas. Yet 25 years ago, large blooms of Noctiluca had never even been seen in the Arabian Sea.
Oman takes Noctiluca seriously. The green gunk snarls up desalination plants that produce drinkable water in the arid country, and aboard vessels. Most fish are not keen on eating Noctiluca, but jellyfish do, and they also get stuck in desalination machinery.
Perhaps even more worryingly, Goes and his colleagues argue Noctiluca has outcompeted members of the local food chain, namely the tiny types of plankton that teeny fish larvae eat. While he does not have the raw data to prove it yet, Goes worries that this disruption potentially imperils fish stocks upon which Oman depends.
“The food chain has been short-circuited,” explains Goes.
Back to Noctiluca. The reasons for its strange flourishing are complex, but a selection of freakish features have made it uniquely adapted to live in a sea that is becoming short on inorganic nitrate (which is important for life), low in oxygen and more acidic because of the Arabian Sea’s warming, according to Goes.
His research has found that the shifting nitrate and oxygen levels in the Arabian Sea is caused by changing weather — fuelled by snow cover loss in the Himalayas.
Glowing in the dark isn’t even the strangest thing about Noctiluca, which comes from a gang of incredibly tiny living things called dinoflagellates, which move about by wriggling a little tail.
Being a single-celled organism hasn’t stopped Noctiluca developing a sort of internal greenhouse that fills up with a symbiotic algae, which give it fuel to grow and survive, and lends it the manky green daytime colour. If you’re wondering how the algae gets into that inner greenhouse, so are scientists — it’s one of Noctiluca’s many as yet unsolved riddles.
Lastly, Noctiluca is endowed with sexual reproduction, which means it can spawn far faster than rivals that divide to replicate themselves.
Noctiluca’s “continued range expansion represents a significant and growing threat for regional fisheries and the welfare of coastal populations dependent on the Arabian Sea for sustenance,” wrote Goes and his colleagues in a 2020 paper.
And its stinky-by-day, glittery-by-night march continues. Goes has been alerted to Noctiluca’s arrival as far as the Gulf, in Emirati waters.
After two decades of observation, Goes and his team are going on the offensive against Noctiluca, trying to find ways to halt its spread. Working with Omani authorities, they are developing early warning systems, using measurements at sea to predict when Noctiluca blooms might spread. And now the scientist says they’re testing a blend of naturally occurring minerals that chokes off Noctiluca blooms, without affecting other organisms, to “control the fire before it spreads”.
Watching jumping fish agitating Noctiluca into sparkles on an Omani beach, you could be forgiven for hoping Goes and his team do not succeed. But if their work teaches us anything, it’s that all that glitters is not good.
chloe.cornish@ft.com
