Studies of the hydrobiology of a tropical lake in north-western Queensland. III. Growth, chemical composition and potential for harvesting of the aquatic vegetation

摘要: The biomass of aquatic plant species and the standing crop submerged were estimated in Lake Moondarra from 1977 to 1979. In July 1978, Salvinia molesta exceeded 53 000 t fresh weight, with a density 167 ha-1 (0.81 kg dry wt m-2). Hydrilla verticillata reached maximum almost 3 m-2 Potamogeton crispus more than double that density. Photosynthetic activity range was high, still detectable at water depths allowing only very low light penetration. Organic nitrogen concentrations high (0.91-4.37% wt), phosphorus (0.07-0.47% wt) appeared be limiting factor for growth plants. Heavy metal varied species, location season but, although generally higher world-wide 'mean' values (48 µg g-1 copper, 11 lead, 14.3 zinc), significantly less those macrophytes heavily polluted environments. H. efficient S. removal nitrogen, zinc, whereas copper lead reverse true. potential using this property plants subsequent harvesting order remove nutrients metals lake is also discussed.