Measure water quality with your phone
TAKE PHOTOS: The colour of the water allows a very accurate impression of the water quality of oceans, lakes, and streams. Bluish water is typically clean, whereas greenish water has more algae. In order to collect global water quality data, German and Dutch scientists have developed the EyeOnWater app. You only need to take a picture of the water surface, compare its colour to a colour scale, and upload everything together with the GPS coordinates of your location.
The water colour reveals whether oceans and streams are of low food value or full of algae.