Are "blue tears" a "beautiful crisis" caused by marine pollution? Online rumors leave Matsu residents helpless

▲ Online articles claim that blue tears are "marine pollution," a "beautiful crisis," or an "ecological warning," leaving locals deeply frustrated. (Photo /Matsu 1234 Youth Homestay- provided by Brother Fu)

Reported by Lin Yuling / Interview and coverage

Numerous online articles claim that the breathtaking "blue tears" and "star sand" phenomena in Matsu are"the ocean crying," "the result of ecological damage from industrial wastewater," or a "beautiful crisis." Yet, these simplistic narratives have left locals feeling quite helpless.In fact, the existence of blue tears also symbolizes a thriving marine ecosystem. Brother Fu, a homestay owner who has long guided tourists on eco-tours to see the blue tears, consulted two biology professors from National Taiwan University and National Taiwan Normal University and concluded that describing blue tears as a "beautiful crisis" is rather inaccurate.

This year, Matsu's "blue tears" and "star sand" appeared earlier than in previous years. Although their numbers haven’t yet peaked, they have once again sparked widespread discussion.Brother Fu, owner of "Matsu 1234 Youth Homestay," said that two of his regular guests are biology professors from National Taiwan University and National Taiwan Normal University. Since the "blue tears chasing craze" began three years ago, they have come to Matsu every year to study these organisms and take samples back to their labs for analysis. Thanks to this, Brother Fu has had many discussions and learned a lot from the two professors.Many people confuse the two, but although both are types of plankton and emit blue light, they are not the same. Blue tears are a type of dinoflagellate called "dinoflagellate algae." Under a microscope, they look as if they’re wearing armor, so simply calling them dinoflagellates isn’t entirely accurate. Star sand, on the other hand, is a type of ostracod — a transparent creature that usually lies on the sand feeding. It only emits tiny flashes of blue light when stimulated by external forces such as waves or human footsteps.

▲ Star sand and blue tears are different organisms — just a gentle step will make them glow, no need to stomp hard. (Photo /

Matsu 1234 Youth Homestay- provided by Brother Fu)▲ Blue tears under a microscope — dinoflagellate algae. (Photo / Screenshot from

webpage)▲ Star sand (ostracod) under a microscope. (Photo / Screenshot from Director Zhou Hongnong of NTU’s Fisheries Research Institute)

Over the years, online rumors have claimed that Matsu’s blue tears are the result of factory wastewater pollution, even calling them "the ocean crying" or a "beautiful crisis." These claims have left locals exasperated and view them as overly subjective. In truth, Matsu’s geographical location — with its broad, shallow seabed at the convergence of cold and warm currents, plus nutrient-rich algae and plankton brought by three rivers from mainland China (the Min River, Lianjiang, and Luoyuan) — supports a diverse array of fish and coastal life.

The presence of blue tears is actually a sign of abundant ecological resources and marine life, not the result of industrial wastewater pollution.Brother Fu explained that marine creatures like fish feed on these plankton. If blue tears were truly polluted, the fish would likely be contaminated too. However, years of literature and records show no cases of people getting poisoned from eating Matsu seafood, with the only exception being poisoning from accidentally consuming pufferfish. Moreover, Matsu’s coastline is very clean, with no foul odors — just the fresh smell of the sea. If there were any pollution, it would be obvious either through smell or environmental changes.

From spring to summer, as humidity rises and seawater temperatures increase, plankton populations grow. They gather, reproduce, and share the shoreline, then become food for fish, which in turn are preyed upon by birds like terns, creating a continuous food chain cycle. All life moves on to the next stage, repeating year after year in an endless cycle. Currently, discussions around blue tears, star sand, and other plankton remain varied, and more research is needed to uncover the full picture.

▲ Tourists throwing rocks to provoke blue tears may harm the ecosystem, a concern for locals. (File photo / Provided by Cao Xiangguan)

Brother Fu said that star sand has a longer lifecycle than blue tears and can still be seen in October and November. Both star sand and blue tears emit blue light when stimulated by external forces, but he reminds visitors

"there’s no need to stomp hard on the sand or throw rocks into the sea." Simply touching them naturally is enough. Overstimulation can prevent them from glowing and may even harm the ecosystem,or worse, cause injuries or accidents."Let’s all take care of Matsu’s natural environment together," he added.“I hope everyone can take good care of Matsu’s natural environment together.”