"Willem Van der Voort" schreef in
bericht news:grfGi.169867

The green you see on the picture is called KROOS in Dutch (watermeal -
duckweed family).

It is floating on the surface, and it is not algae.

Indeed Willem, we call it "eendenkroos", it comes and it goes.
In the old days farmers collected it to improve the soil of their gardens..
Here a picture to see how the smal plants can cover a great deal of the
water.
--
Groeten
Bouler (The Netherlands)