Algal growth control by a barley straw extract.
In recent years, there has been an apparent increase in the occurrence of harmful algal blooms occurring in potable waters. The potential of a simple barley straw extract to inhibit algal growth was assessed. Algal growth in lakewater was inhibited by the addition of barley straw (1% w/v), with the chlorophyll a concentration remaining below the original level (40 micrograms l-1) throughout the experiment. In contrast, in the presence of wheat straw, algal biomass increased, reaching a final chlorophyll a concentration of 1160 micrograms l-1 after 28 days. Analysis of the remaining particulate straw at the end of the experiment showed that the lignin content of barley straw had increased significantly from 10-33% (w/w). Further, a preparation of a simple aqueous extract from the decomposed-barley straw was found to inhibit the cyanobacteria Microcystis sp. and the algal species Scenedesmus, with chlorophyll a levels some 10-fold lower than in untreated flasks. This study shows that a decomposed-barley extract, even in a very dilute concentration (0.005%) was capable of inhibiting the growth of Microcystis sp., a commonly occurring cyanobacterium which produces the toxin microcystin and has been responsible for some of the most serious pernicious algal blooms in the UK.
Department of Biological Sciences, John Tabor Laboratories, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, UK. andrew@essex.ac.uk
A S
AS
Ball
M
M
Williams
D
D
Vincent
J
J
Robinson
D002734:Chlorophyll / Q000032:analysis*; D000077194:Chlorophyll A; D000460:Chlorophyta / Q000254:growth & development / Q000378:metabolism*; D000458:Cyanobacteria / Q000254:growth & development / Q000378:metabolism*; D001467:Hordeum / Q000737:chemistry*; D008031:Lignin / Q000032:analysis; D014908:Triticum / Q000737:chemistry
D002734:Chlorophyll; D008031:Lignin; D000077194:Chlorophyll A