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
Rivers and lakes of Armenia Rivers and lakes of Armenia The Rivers and lakes in Armenia are mainly powered by fresh water. Throughout history Armenia has been called Nairi by the Assyrians meaning the "Land of the lakes and rivers". The Armenia is home to many rivers and lakes. The largest river of Armenia is the Arax, which lies on the country's border with Iran and a large part of the border with Turkey. Its major tributaries are the Akhurian, Kasagh, Hrazdan, Azat, Arpa, Vorotan and Voghdji rivers. The largest rivers in north west part of the country are the Debed and Aghstev, while smaller