Tag : Looms

Washington: Algae blooms are a growing problem in the lake-rich regions of the world. Not only are the floating green scums a nuisance for anyone hoping to enjoy the water, but they can also turn toxic and threaten public health. The main driver behind these blooms is phosphorus, an element used widely in agriculture to fertilize crops, that can run from the land and into lakes -- especially during heavy rains. A new study from the University of Wisconsin-Madison shows how soon after a storm phosphorous "loading" sparks algae explosions, but also describes the many other factors that weigh on when and whether the lake reaches a tipping point. "The fact that you just had a big storm doesn't mean now you're going to get a big [algae] bloom. The blooms are much more complicated." says Steve Carpenter, lead author of a report published in the Proceedings of the National Academy of the Sciences. Carpenter, director emeritus at UW-Madison's Center for Limnology and professor emerit of integrative biology, led a team of researchers in a deep dive into long-term datasets collected on Lake Mendota, Madison's largest and longest-studied body of water. The scientists knew that only a handful of the highest precipitation storm events delivered about three-fourths of the phosphorus to the lake each year. And, in other lakes, previous research had documented big algae blooms following on the heels of big storms. But, in Lake Mendota, this dynamic is more complex. While phosphorus is undoubtedly the key ingredient for an algae bloom, Lake Mendota can stew for quite a while before serving one up. In fact, the report found that the mean lag time from a big storm to a big bloom is 15 days, with some delays between a heavy, phosphorus-delivering rain ...