After sunset this week, a quiet stretch of Dickinson Bayou suddenly turned nightclub chic, lighting up in electric blue every time the water was disturbed. Tap it with a net, send a boat through, watch a fish dart by, and the dark surface briefly explodes into neon. Longtime neighbors, phones out and jaws dropped, say they have not seen anything like it in decades on the bayou.
Homeowners Judd and Thuy Gottlieb were among the first to chase the glow after spotting a social media post. As reported by News 4 San Antonio, they headed to the canal behind their house after dark, dragged a net through the water and watched bright blue streaks flare up wherever the surface was stirred. They shared photos and video that quickly drew even more curious onlookers.
The Houston Chronicle described boats carving through inky water and leaving luminous wakes behind them, like someone had flipped on underwater LEDs. A local resident told the paper the eerie light show stretched from the railroad bridge all the way down to the bay. Some people who have lived along Dickinson Bayou for decades say the color is unlike anything they have seen, and one neighbor suggested a recent tidal shift may have pushed glowing marine organisms farther inland.
What’s lighting up the water?
Scientists say the spectacle is bioluminescence from tiny plankton commonly nicknamed “sea sparkle.” According to Britannica, the species Noctiluca scintillans produces bright blue light when it is mechanically disturbed. The flash comes from a chemical reaction in the cells, involving luciferin and the enzyme luciferase, that flips on for an instant whenever the organisms are jostled.
How long will it last, and is it safe?
There is no set schedule for the glow. Experts say blooms like this can fade after a single night or hang around for several days, depending on water temperature and the availability of nutrients. Jamie Steichen of Texas A&M University at Galveston told MySA that it is safe to swim during these events because this species typically does not produce toxins. Very dense patches can carry high ammonia levels, which may irritate the skin, so brushing up against thick concentrations is not exactly a spa treatment.
Why scientists pay attention
Researchers caution that large or growing Noctiluca blooms can reflect shifting temperatures and nutrient levels that reshape coastal ecosystems, and some studies have linked an increase in these blooms to warming seas. Reporting and research in other regions have raised concerns about ecological impacts, and state water quality documents note that Dickinson Bayou has a tidal segment and a history of nutrient and oxygen problems that can influence when and how blooms form. The Financial Times and the TCEQ provide further context on those concerns.
Locals plan to keep watching
The Gottliebs say they plan to be out on the bank most nights for as long as the glow sticks around, and local media report that people are already driving in from other towns hoping to catch the show. As News 4 San Antonio noted, parts of the bayou have effectively become an impromptu nighttime attraction…