Ankistrodesmus
 
Ankistrodesmus is very common throughout North America. The genus is usually found within the plankton of freshwater ponds and lakes, and sometimes inhabits artifical ponds, temporary pools, and waterfalls.
 
Ankistrodesmus and some other microscopic green algae and euglenoids have a high tolerance for the copper treatments (usually copper sulfate) that are commonly used to control algal growth in water supplies, reservoirs, and recreational areas.