NASA Noticed an Unusual Glow in Southern Australian Waters — Experts Know Exactly What It Is

Orbiting about 400 miles from Earth, a NASA satellite is keeping an eye on the planet’s ongoings. The name is PACE, short for Plankton, Aerosol, Cloud, Ocean Ecosystem. In November 2024, PACE detected a mysterious bluish glow dancing in the waters off the southern coast of Australia. At first, the dazzling blue-green glow puzzled the scientists. But when they delved deeper into the investigation using state-of-the-art technology, they found that the unreal shimmer was something these experts call “bioluminescence.”

NASA’s scientists detected the bioluminescence using an advanced Ocean Color Instrument (OCI). The unreal glow, spotted in the Great Australian Bight and Tasman Sea, was a massive bloom of phytoplankton, tiny organisms that possess the ability to create “light.” According to an explanation by National Geographic, bioluminescence is the light produced by a chemical reaction within a living organism. Unlike the typical light, which has a warmer tone, this is termed the “cold light.” It’s nothing but a seductive type of chemistry, provoked by a reaction between two chemicals: luciferin and either luciferase or photoprotein.

As they swim around in the waters, the light-generating organisms emit light as part of a defense mechanism against predators or to attract their mates. Another way they generate light is when jostled or disturbed in the dark waters. Whenever a large creature like a whale, a fishing boat, or a human hand unknowingly disturbs the blooms of these organisms, their defense mechanism activates, which triggers a tailspin of light-emitting chemical reactions. Once the light is generated, it spreads around like a sparkly trail each time someone touches or agitates the water.

In another article, National Geographic describes this phenomenon by calling it “a ruthless game of right place, right time.” The phenomenon requires warm, calm, and windless waters, as well as low-lit new moon nights, to ensure memorable displays. This particular glow was detected somewhere between Southern Australia and Tasmania, a region known for its fierce, dynamic currents and balmy swirls of breeze. In addition to the chemical reaction unfolding through the contact between the plankton and something else, the glow is sometimes also produced due to a high concentration of chlorophyll, as suggested by Sustainability Times.

As phytoplankton extracts and absorbs nutrients like nitrogen and phosphorus, released from the decaying marine life, hefty concentrations of chlorophyll build up inside their bodies, which becomes the reason behind the glimmering waters of the Southern Ocean. In this case, however, it wasn’t just the aesthetic or visual treat that PACE showed us. It was also a marker that scientists could utilize to determine the health of the Australian marine ecosystem. Similar instances of glowing phytoplankton filaments in Australia's Bonney Coast region were observed by the Suomi NPP satellite using its VIIRS (Visible Infrared Imaging Radiometer Suite) sensor in January 2024, as per NASA Earth Observatory.