ABSTRACT
Freshwater ecosystems consist of communities of different types of aquatic organisms and their ambient environment, namely biotic and abiotic components. Water hyacinth, as a large and floating vascular plant, grows intensively in suitable conditions such as temperature, nutrition and light, may cover a large area of water surface, reduce underwater light intensity and hinder air exchange at the water-air interface, thus negatively affecting water ecosystem. On the other hand, water hyacinth could absorb pollutants from water, and its well-developed fibrous root system could provide shelter and habitat for aquatic animals and microorganisms; hence, it may have positive effects on the structure of aquatic animal community if the mat is relatively small. The effect of water hyacinth on aquatic vascular plants is similar to that on phytoplankton. On one hand, water hyacinth floating and growth affect incident light, reducing availability of underwater light energy for photosynthesis of submerged macrophytes.
