CHEMICAL COMPOSITION OF AQUATIC MACROPHYTES. III. MINERAL COMPOSITION OF FRESHWATER MACROPHYTES AND THEIR POTENTIAL FOR MINERAL NUTRIENT REMOVAL FROM LAKE WATER

Mineral composition of aquatic plants from Chemung Lake and Lake Ontario was investigated. The four species harvested at progressive dates in 1974 showed no trend of variation in their individual mineral contents. This was probably because some dates did not correspond with a specific growth stage. All the four species harvested at three dates, except Myriophyllum spicatum and Vallisneria americana collected in September, were extremely high in ash. Myriophyllum and Vallisneria harvested in September represented immature plants, since these were obtained from sites harvested previously and consequently were much lower in ash. Calcium and phosphorus levels varied with the ash content, with the former being the major cation in all species. Analyses of washed and unwashed samples of several macrophytes harvested in 1975 showed that extremely high ash was the result of surface calcification with CaCO 3 . Silica, Co, Cu and Se were present at safe levels for feeding to animals. Results indicated that harvesting aquatic plants has the potential to remove large quantities of mineral nutrients from the aquatic environment, and feeding good quality plants to herbivore and poultry could meet their requirements for many of the mineral elements.