Hi all,
As Clive suggests algal spores are everywhere in the environment, for example the freshwater green algae (Chlorophyta) produce a special hard walled "spore", an "
akinete" to facilitate aerial dispersal from drying ponds. Have a look at "
Survival strategies of the algae" by Greta A. Fryxell on Google books for more details.
First time I've heard a post on algae being a friend"
I look at it like that, if you don't have any there is something wrong. Just don't look on it as the hated and feared algae, but think of it as the wholly beneficial aufwuchs or "biofilm". In terms of water quality the big difference in aquarium keeping is plants or no plants, it doesn't matter whether the plants are algae or higher plants.
Maybe we should look at it from now on the same as a DC indicating problems. Creating a truly sterile environment has always been problematic, as soon as we mess with nature it comes back even stronger to bite us. You only have to look at MRSA in hospitals....."
Very true, that is why I like limited intervention, stability and slow change, things may get out of balance, but it all happens fairly slowly giving you much more of a chance to nudge the parameters until things stabilise at a new equilibrium. I use an
ad hoc "algal early warning system" and I expect most of us do this, in that, for example, I expect to have both BBA and a fuzz of green algae on older leaves, but normally I have very little BGA. Therefore if the BGA suddenly starts to proliferate, or I get a unicellular green algal bloom in the water, something has changed, and need to find out what it is, and then decide if I need to attempt to do anything about it.
The higher plants and the green algae share exactly the same photosynthetic pigments and physiology, you can't create conditions that allow your aquarium plants to grow but exclude them, it is not possible, to all intents and purposes they are the same thing. What you can do however is nudge the conditions towards an equilibrium where the growth of the higher plants is favoured, this can be a highly interventionist high tech. approach, where extremely good growing conditions allow the plants to grow at a much faster rate than the algae, or they can be a much lower tech. approach where conditions are sub-optimal for both plants and algae, but they remain in a balance we find aesthetically acceptable.
cheers Darrel