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. As you can see, it takes more than that to deter Qingdao beach-goers.
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.
The exact causes of algal blooms are complex, but generally speaking they are caused by an imbalance of nutrients that the phytoplankton species making up algae can feed on. Human fertilizers are a common source of these nutrient spikes, which in part accounts for the uptick in algal blooms in recent years. Indeed, this particular beach - which on any other day is one of the city's premiere tourist destinations (and, depending on how you feel about swimming through algae, still is) - has seen three such blooms in the last five years alone.
Check out more awesome images of this latest bloom at The Daily Mail.