Originally published by whro public media
Researchers at Old Dominion University sample water in the area several times a week during the summer, when algae blooms are most likely to develop, said Margie Mulholland, a professor in ocean and earth sciences. On July 22, her team confirmed a bloom of the species Margalefidinium polykrikoides, nicknamed “Marge.” (No relation to Mulholland.) Colleagues at the National Oceanic and Atmospheric Administration then tracked it via satellite imagery as it slowly moved through the region, carried by shifting currents. The bloom has made it to parts of the James and York Rivers and even around the coast to the Oceanfront. It now seems to be dissipating, though a patch identified by satellite near Tangier Island may be connected, Mulholland said.
Algae are a crucial part of the ecosystem, “the base of the food web,” Mulholland said. Blooms become harmful when there is an overgrowth, “when you get too much of a good thing.” They can be harmful in different ways. Some produce toxins that can hurt people and marine life, Mulholland said. Others might not be inherently toxic, but as they decay, the bacteria consume oxygen, creating what are called “dead zones” in the water. The massive plumes also block sunlight from reaching underwater plants. Blooms are often spurred by nutrient pollution such as fertilizer that runs off land and fuels algae growth. They also like heat, multiplying much faster in warmer waters. But Mulholland said scientists don’t yet understand how exactly they form. “Marge” started appearing in the lower Chesapeake Bay in the early 1990s and has since bloomed nearly annually. But it was absent the past few summers. “So this year, it’s caused quite a stir,”
ODU is part of a broad coalition tracking and studying algal blooms in the bay, including the state, NOAA, the Virginia Institute of Marine Science and the Mid-Atlantic Regional Association Coastal Ocean Observing System. They are trying to develop a real-time alert system to warn people when harmful algae is on the rise. “Sort of like the flood alerts we get from the city when there’s going to be flooding, but we want a bloom alert for people on the water that might want to avoid bloomy waters,” Mulholland said.
