Algal growth control by terrestrial leaf litter: a realistic tool?

Citation
I. Ridge et al., Algal growth control by terrestrial leaf litter: a realistic tool?, HYDROBIOL, 396, 1999, pp. 173-180
Citations number
17
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Aquatic Sciences
Journal title
HYDROBIOLOGIA
ISSN journal
0018-8158 → ACNP
Volume
396
Year of publication
1999
Pages
173 - 180
Database
ISI
SICI code
0018-8158(199902)396:<173:AGCBTL>2.0.ZU;2-Y
Abstract
When barley straw and deciduous leaf litter decompose aerobically in water, inhibitors are released that suppress the growth of nuisance algae. Barley straw has been widely used for algal control in small, shallow lakes and w e review the advantages and disadvantages of the method. It is particularly effective at promoting the switch from algal to macrophyte domination. Des pite its cheapness and apparent safety in the short term, however, the use of barley straw requires considerable management effort and the long-term e cological safety of such un-natural litter inputs is unkown. We therefore r ecommend it to lake managers primarily as a short-term measure. Deciduous l eaf litter from a range of woody species can suppress the growth of Chlorel la and Microcystis very effectively in laboratory bioassays and, in field t rials with medium-sized ponds, the addition of leaf litter produced signifi cant inhibition of the filamentous alga Cladophora glomerata. We followed t he development of algal inhibitory activity over 2.5 years with freshly fal len oak leaves placed in a large tank of aerated water and using Chlorella as the test species. Two periods of inhibitor release were identified: 4-90 days (early phase) when soluble, relatively stable inhibitors were present in tank liquor, probably generated from oxidized tannins; and 120-900+ day s (late phase) when inhibitors were relatively unstable in solution and wer e associated primarily with fine particulate organic matter (FPOM). Late ph ase inhibitors may, as suggested for barley straw, be generated during the oxidative breakdown of lignin. The prolonged and powerful anti-algal proper ties of these natual litter inputs offer possibilities for low-effort, sust ainable management of lakes and catchments so as to reduce the problem exce ssive algal growth.