Almost exactly a year before the Florida bloom, another stretching 7,500 square miles washed ashore in Qingdao, China, a popular beach destination. Government officials called in hundreds of boats and bulldozers to remove it. The green blob appeared again earlier this month.  The largest and most dangerous algal bloom ever recorded, which ranged from Central California to British Columbia, produced high levels of a toxin that last year closed crab and clam fisheries along the West Coast.  “The season didn’t open for four and a half months, which meant slip rents went unpaid, house payments went unpaid, guys were having trouble getting groceries to feed their families,” said Tim Sloane, the executive director of the Pacific Coast Federation of Fishermen’s Associations.  Algae is a catchall term referring to a wide variety of aquatic organisms that generally rely on photosynthesis for energy and reproduction. Blue-green algae are cyanobacteria, for instance, while red tide is composed of tiny dinoflagellates. Seaweed is a sophisticated alga, as is kelp.  Blooms are a natural occurrence. According to Dr. William Cochlan, a senior research scientist at San Francisco State University, Native Americans for centuries knew to avoid bioluminescent water. Scientists would later discover that the glow was caused by dinoflagellates that also produce a hazardous neurotoxin.  Many algal species produce similar toxins. When vast blooms occur, these poisons may spread through the environment and up the food chain to fish and animals that feed on them. Cyanobacteria produce microcystins, for example, which can affect the liver and can be deadly to humans — one reason Toledo banned the drinking water.  Although they occur naturally, algal blooms are being intensified by human activity in ways that scientists are still trying to quantify. Chief among the culprits: runoff from farms, feedlots and municipal sewer systems.  “The bloom itself is the visual manifestation of nutrient overenrichment in lakes,” said Tim Davis, an ecologist at the National Oceanic and Atmospheric Agency’s Great Lakes Environmental Research Laboratory in Ann Arbor, Mich. “In freshwater systems, both nitrogen and phosphorus are the main nutrients.”  In Florida and the Great Lakes, nitrogen and phosphorus come mainly from fertilizers used in large farming operations, along with septic tanks, manure and storm water. Scientists have been aware of the nutrient problem for decades: It’s partly why phosphorus was removed from laundry detergents.  The vast algal bloom in the Pacific last year was also fed in part by El Niño, the mass of warm water that forms periodically off the West Coast. But longer-term climate change may also be playing a role, some experts say.  Warming atmospheric temperatures and wetter weather in some parts of the country increase the nutrient-laden runoff into streams, lakes and the ocean. And as ice melts in the Arctic, sea temperatures are rising and more sunlight is filtering into the ocean.  “Some of the features of climate change, such as warmer ocean temperatures and increased light availability through the loss of sea ice in the Arctic, are making conditions more favorable for phytoplankton growth — both toxic and nontoxic algae — in more regions and farther north,” Kathi Lefebvre, a biologist at NOAA’s Northwest Fisheries Science Center in Seattle, wrote in an email.  “It is likely that toxic blooms will continue to increase and expand as these features of climate change continue,” she added.  Dr. Davis said he also believed that climate change was working against efforts to prevent algal blooms.  “I certainly believe as a scientist that climate change will influence the size and intensity of these blooms,” he said. “If nothing changes — the increase of rainfall, the increase nutrient loads, warmer water — all of this could lead to larger blooms that last longer and are more toxic.”  Florida’s crisis is only the most recent example, Dr. Cochlan of San Francisco State University said — yet no new funds have been appropriated at the federal or state levels to study the growth and toxicity in these blooms, despite their increasing impact throughout the country. In a letter to President Obama on July 12, Florida legislators asked for federal funding to avert further disaster.  Back in 2014, Florida voters approved Amendment 1, setting aside an estimated $650 million in the program’s first year for the state to buy agricultural land south of Lake Okeechobee as a new pathway for discharge into the Everglades.  The hope was that the ecosystem would provide a natural filter for algae and other contaminants, as it once did. But in the end, the state decided not to buy the land, instead sparring with Environmental Protection Agency over its efforts to enforce the federal Clean Water Act.  “A lot of this has to do with legislation, all the way from the watershed down into the lake,” Dr. Davis said. “It needs to be a mutual effort on all sides. The more we understand about the blooms, the more we can do to reduce their impact.”
Algal blooms that have recently hit southeastern Florida waters are the latest of such environmental disasters that have hit with increasing frequency.