Small boasts stay berthed in the algae-filled Chaohu Lake in Hefei, capital of east China's Anhui province June 11, 2007. It is reported that blue-green algae has extended five square kilometers here but does not threaten drinking water supplies. Environmental experts and officials are closely monitoring the potentially harmful algae bloom in Chaohu Lake, China's fifth largest freshwater lake, for signs of a massive bloom in the hot and arid weather. [China Foto Press]