Cyanotoxin which is why they are usually green or blue. Cyanobacteria are found almost everywhere; in oceans, lakes and rivers as well as on land. They flourish in Arctic and Antarctic lakes, hotsprings and wastewater treatment plants. They even inhabit the fur of polar bears, to which they impart a greenish tinge. Cyanobacteria produce potent toxins, but they also produce helpful bioactive compounds, including substances with antitumour, antiviral, anticancer, antibiotic and antifungal activity, UV protectants and specific inhibitors of enzymes. Cyanotoxins are often implicated in what are commonly called "red tides" or "harmful algal blooms". Lakes and oceans contain many single-celled
Great Lakes Areas of Concern just the past three years. There are many examples of this problem in each of the Great Lakes, as well. The Great Lakes have been damaged by more than 180 invasive and non-native species. Some of these species include the zebra mussel, quagga mussel, round goby, sea lamprey, and alewife. Invasive plants include purple loosestrife and Eurasian watermilfoil. As well as throwing off the habitats of native species and the food web of the ecosystem, invasive species also threaten human health and have a major negative impact on the Great Lakes economy by damaging fisheries, agricultural industries, and tourism. Point-source