China’s Yellow Sea has recently gone green, caused by the nation’s greatest algae growth to date. Since 2007, algae have swamped the waters every summer, but 2013’s bumper bloom covered a record-breaking 28,900 sq km (11,158 sq miles).
Despite the fun and frolics on the beach at Qingdao in the eastern Shandong province, this thick covering of algae stops sunlight and oxygen penetrating the water, which suffocates sea life. Scientists don’t know why the tide has turned green, but they agree the carpet of algae comes from an ecosystem imbalance, and is probably the result of human activity, such as agricultural and industrial pollution.
Harmful algal blooms (HABs) form where colonies of sea-inhabiting plants, called algae, develop at a rapid rate, causing devastation to local marine life. In the right conditions, a population of algae can double in hours.