What will you discover?
Algae, nutrients and still water - Nila explains why a pond turns green.
Key takeaways
- A little algae is normal and healthy; a thick green mat is not.
- Fertiliser and detergent runoff are the usual extra food.
- Still water heats up and lets algae grow faster than flowing water.
- When algae die and rot, they use up the oxygen fish need.
Questions this video answers
Is green pond water dangerous?
Some algal blooms release toxins, so it is best not to swim in or drink thickly green water.
How can a green pond be helped?
Stop the nutrients entering it, keep the water moving, and plant native water plants along the edges.
Take the learning further
Visit a local pond twice, a month apart. Photograph the same corner both times and compare how green it is.
