Re: Barley Straw?

From: Chris Teichreb (
Date: Tue Jun 22 1999 - 15:10:24 PDT

Date: Tue, 22 Jun 1999 15:10:24 -0700 (PDT)
From: Chris Teichreb <>
Message-Id: <aabcdefg2287$foo@default>
Subject: Re: Barley Straw?

Hi Chris,

        When barley straw starts to decompose in water, it releases a
substance called dissolved organic carbon (DOC). One of the fractions of
DOC are humic substances (humic and fulvic acids) which add the pale
yellow colour to the water. Humic substances do several things, first,
they attenuate photosynthetically active radiation (PAR), which basically
reduces the amount of light available for the algae. Second, they bind to
phosphorus and to exogenous enzymes secreted by algae for that bound
phosphorus, basically starving the algae of food. Finally, when they are
phtodegraded by UV-B radiation, they act as a substrate for heterotrophic
bacteria, which are competitors with algae for limited P sources. The
bacteria outcompete algae for the leftover P, and reduce algal biomass.
There's been at least a few published reports looking at reduction of
algal and macrophyte biomass in golf course ponds through barley straw

        Can it be used for Aldrovanda and Utricularia? Well, I'd say a
tentative yes. However, peat also has DOC in it which is released into
the water (again, that yellowish colour). Since barley straw may be of
unknown origin, and may have been treated with pesticides, herbicides, and
fertilizers, I'd suggest against it. My advice? Change the water
frequently so as to avoid a build up of algae, or, grow a surface cover of
something like Wolffia (sp?) or another floating plant.

Flexing my brain muscle,


 On Tue, 22 Jun 1999, chris wrote:

> I have been watching a pond newsgroup. Someone on there mentioned
> using barley straw to get rid of hair algae. Does anyone know about
> this. Could it be used for aldrovanda and utrics.? And if so,
> where can one get it?
> Chris F.
> [HTML file part2 deleted by listprocessor]

Chris Teichreb
Department of Biological Sciences
Simon Fraser University
Burnaby, B.C.

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