Stunning But Deadly Algae Lights Up Hong Kong Waters

The waters along Hong Kong’s shore just got a little bit brighter, thanks to Noctiluca scintillans, also known as “sea sparkle.” The iridescent algal bloom glows a faint blue color when disturbed, and many residents of the area have taken to throwing rocks in the water to watch the beautiful phenomenon. Long exposure photos reveal an area lit up with the fluorescent creatures. Seth Borenstein of the Associated Press writes, “It looks like algae and can act like algae. But it’s not quite. Noctiluca is a type of single-cell life that eats plankton and is eaten by other species.” Jealous that the bloom hasn’t taken off in your local river? Not so fast, say scientists.

Despite their blue coloring, the algal bloom taking place in Hong Kong is known as a red tide. Red tides can occur as a result of pollution in the water. “The plankton and Noctiluca become more abundant when nitrogen and phosphorous from farm run-off increase,” according to Borenstein. Their increased presence depletes oxygen levels in the water, killing out many fish. Even when the Noctiluca eventually dies, they sink to the bottom and decompose, further depleting oxygen levels. Noctiluca‘s role as both prey and predator can eventually magnify the accumulation of algae toxins in the food chain, according to oceanographer R. Eugene Turner at Louisiana State University. It can get to the point where even bottom feeders such as crustaceans and mollusks can no longer survive in the area, thus creating a dead zone. It can take years for an ecosystem to recover from these blooms.

Hong Kong is not the only area that is dealing with these deceptively destructive organisms. Noctiluca is responsible for a dead zone in the Arabian Sea the size of Texas, and it only seems to be getting bigger. The bloom in that area has wreaked havoc on local fisheries. Though no fish have been reported to have died thus far from the bloom in Hong Kong, the large amount of pollution in the area is only going to foster further increase of Noctiluca in the waters.