Satellite eye on Earth: September 2017 – in pictures
Algal blooms, hurricanes and volcano fields are among the images captured by Nasa and the ESA last month
A potentially harmful algal bloom covered more than 700 square miles in the western basin of Lake Erie in late September, turning the lake bright green and alarming residents and local officials. Blooms tend to thrive in Lake Erie during summer, sustained by warm water temperatures and nutrients from farm runoff. This year, the bloom had been ongoing since mid-July.