Swimming in Green Algae - China

The algae is in full bloom off of the Chinese city of Qingdao, creating a giant greet splotch measuring as much as 70 meters by 100 meters

Green algal blooms aren't dangerous to humans - although the same can't be said for red tides, which are caused by another algae species and can create harmful toxins - they do consume vast quantities of oxygen, which can be devastating to marine life. This particular swath of algae is just a tiny part of the larger bloom, which stretches some 300 miles across the Yellow Sea.
Beach workers, volunteers, and visitors helped clean a carpet of algae about 1,300 feet long and 98 feet wide, China's state-run media reported. Local maritime agencies believe that rising water temperatures have supported the algae's rapid growth, according to state media.