Pink water looks alarming but it’s not harmful.
The colour is due to purple sulphur bacteria which grow when there’s an abundance of plant debris in the bottom of the pond, producing a lot of hydrogen sulphide gas (the smell of rotten eggs). Purple bacteria use hydrogen sulphide instead of water to power their photosynthesis.
Pink ponds may be the result of a perfectly natural build up of plant debris or the result of pollution by rotting organic matter or sewage.
So being pink doesn’t automatically mean your pond is polluted – but it does mean it has a lot of organic matter.
Thanks to Scott for the photo of water from his pond, and Nick and Chris for the pond photo.
Tags: Pink ponds, Purple bacteria


September 9, 2010 at 8:43 pm |
[...] seeing a reference to an earlier post (here – Pink Ponds), this pond also had some purple bacteria – a sure (though natural) sign of oxygen stress and [...]
July 30, 2011 at 5:27 pm |
So should I clean my pond out that has this pink/purple sludge in it? Any advice would be extremely helpful.
August 2, 2011 at 2:03 am |
Wow, I’ve never seen a pond so coloured by bacteria. I’m writing a piece on Pink Lake in Quebec – a meromictic lake with purple sulphur bacteria at the chemocline. Would you mind if I used your picture of the jar for my post, please?
August 6, 2011 at 3:10 pm |
You’re welcome to use the pic. Please acknowledge it to Pond Conservation. Jeremy