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
Hazel (given name) Hazel (given name) Hazel is a primarily female given name meaning "hazel", from the name of the tree or the color. It is derived from the Old English "hæsel". It became a popular name in English-speaking countries during the late 19th and early 20th centuries, along with other names of plants or trees used for girls. The name was the 211th most popular name for girls born in the United States in 2011 and the 52nd in 2016. It was last popular at the turn of the 20th century, when it was among the 25 most popular names for girls.