in germany there are many places where it gets truly dark at night one of them is lake state heenan brandenburg ideal can. missions for a unique experiment it's 3 o'clock in the morning this is when watervliet tend to come to the surface of the lake to feed on alki biologist is waiting for them. the light from their head torches would disturb the experiment so they switch them off only infrared light is allowed. hoka and his team are exploring the effects of sky glow on water. they've positioned l.e.d. lights in circles in a number of test basins they simulate various degrees of light pollution. and. this is explained it's extremely hard to develop a test model which allows you to observe the effects of sky glow on an ecosystem what we have here is a very very diffuse light but it still affects vast swathes of landscape night. areas across germany europe all over the world are affected by sky glow in. the sky go into the top. 24 test basins make up a floating laboratory the researchers will be trying to identify the extent that sky glow affects the underwater world the life processes of marine