Re: Water Lenses

Michael Hasemann (jmh@tko.vtt.fi)
Wed, 22 Feb 1995 09:34:57 +0200 (EET)

>
> > Sorry for the confusion I wrongly assumed the English translation
> > would follow the German or Finnish one. I might be wrong with Lemna
> > minor. It's a little bigger (about 3-4 mm in diameter).
>
> No problem with the confusion--I knew exactly what you were talking
> about. It seems like almost every place around here that sells
> equipment for installing a backyard pond also sells this stuff.
> Strange, though, that I've never seen it growing wild. It seems
> extraordinarily prolific.
> Does anyone else grow this with other aquatics? Since it would block
> excessive light, I wonder if it would help keep algae down.
> Especially since it even clogs the clear plastic trays my other CPs
> sit in...
>

I have virtually no algae in that tray despite strong lightning and
a rather high temperature. I suppose this is due to the following
reasons:

1. The water lenses take nutrients out of the water and block some
light. (BTW: I got to know about a German expression which somehow
relates to "duckweed": Entenschnatter. Ergo: The naming follows the
principle in Finland, Germany, and England/America, like Blumenkohl,
Sonnenblume and Butterblume (Taraxum off.?).

2. The water is constantly aerated which causes a high oxygen level
and thus algae-eating microorganisms can keep up with the algae growth.

3. The pH-level is supposedly low.

..Michael

-- 
  Michael Hasemann | Technical Research Centre of Finland - Automation
		   | Kaitovayla 1, P.O. Box 13023, 90571 Oulu, Finland
                   | Fax: +358 81 5512320 Tel: +358 81 5512239 
  jmh@tko.vtt.fi <-email-------------www-> http://www.kau.vtt.fi/~jmh/