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Several leaf characteristics, including toughness and total phenols and condensed tannins, were measured in Australian rain forest leaves of different ages and related to observed herbivory rates. In most cases, toughness and chemical toxicity increased as leaves aged, and corresponding insect grazing decreased. Herbivory losses ranged from 4.8% to 32.5% leaf area losses, and were more positively correlated with toughness than with phenolics. It is suggested that a suite of factors, including physical and chemical characteristics of leaves as well as spatial and temporal factors, interact to create variation in grazing intensities.

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To cite this article: J.D. Box (1980) A simple technique for washing microalgae in preparation for laboratory culture experiments, with particular reference to Microcystisaeruginosa Kutz. emend. Elenkin, British Phycological Journal, 15:2,[125][126][127][128][129][130]

In the course of limnological investigations, crystals were observed to form during the spectrophotometric determination of iron(I1) in aqueous solutions using 2,4,6-tri(2'-pyridyl)-lJ3,5triazine (TPTZ). The crystals were first noticed about 15 min after the reagents had been added and interfered in the absorptiometric determination of the iron(I1) -TPTZ complex.The presence of crystals has not been reported before in limnological methods using TPTZ1-3 and their appearance was therefore investigated. Experimental ReagentsAll reagents were of AnalaR grade, except for TPTZ. Acetate bufer, 2 M.Hydvox-lnmmonium chloride. TPTZ solution, 5 mM. Dissolve 0.1651 g of TPTZ monohydrate (BDH Chemicals) in 100 ml of 0.1 M hydrochloric acid.Iro?z(II) solzttion. Dissolve 0.702 1 g of ammonium iron( 11) sulphate [FeSO,(NH,),SO,. 6H20] in 1 1 of distilled water acidified with 5ml of concentrated sulphuric acid to give a stock solution containing 100 pg ml-l of iron(I1).Dissolve 272 g of sodium acetate (CH,COONa.3H20) and 115 rnl of glacial acetic acid in 1 1 of distilled water.Dissolve 10 g in 100 ml of distilled water.

Algal growth in water treatment plants can lead to the introduction of toxin and odour compounds from cyanobacteria and causes filter fouling. Here, we investigate the use of woven polypropylene covers and a proprietary copper sulfate formulation (EarthTec) to prevent algal growth within mesocosms designed to simulate settling basins. Chlorophyll a, soluble nutrients, weather patterns and cyanobacterial gene abundance were measured. The covers suppressed algal and cyanobacterial growth in mesocosms, likely due to a combination of light blockage and prevention of insects from entering the mesocosms. In contrast, mesocosms amended with EarthTec exhibited little difference from the control mesocosms in terms of algal growth. qPCR analysis revealed that only a small fraction of cyanobacteria in the system contained genes necessary for the production of the microcystin toxin. Despite differences between mesocosms and full‐scale settling basins, the data here suggest that woven covers can suppress algal growth while minimising evaporative water losses.