Effect of four wetland plants on nutrient removal and growth of eutrophic algae

Abstract

We studied the removal of chlorophyll-a and eutrophic alga Ankistrodesmus acicularis by mixed and monoculture constructed wetlands of four common wetland macrophytes, Echinodorus berteroi, Hydrocotyle sibthorpioides, Vallisneria natans and Hydrilla verticillata. We also tested the effects of the macrophyte culture solution on the growth of three common eutrophic algae: Chlorella pyrenoidosa, Scnedesmus obliquus and Anabaena flosaquae. The wetlands had significant effect on the removal of chlorophyll-a and A. acicularis. ANOVA results indicated a significant difference existed among different wetlands (P < 0.01). There was generally no significant difference between the mixed and the monoculture wetlands, while the mixed wetlands generally showed significant difference between them. Results also indicated that there were significant differences in the effect on the growth of three algae among the culture solutions of different wetlands (p < 0.01). Almost all mixed culture solutions had a significant difference from their monocultures. Similarly, the monoculture treatments generally showed significant differences from their corresponding mixed treatments. However, combinations of different macrophytes generally cannot increase the effect intensity. The results indicated that combinations of macrophytes can produce different effects on alga growth from their monocultures and from their combinations with other macrophytes. Different algae showed different levels of susceptibility to the plant culture solution, and a same culture solution had different effects on different algae, including inhibiting, promoting, or neutral effects.

The Sustainable Treatment Effect of Constructed Wetland for the Aquaculture Effluents from Blunt Snout Bream (Megalobrama amblycephala) Farm

“…It has been confirmed that aquatic macrophytes can inhibit the growth of algae and control algal bloom [52]. The inhibitory effect may be related to competition for nutrients, light and other resources with algae [52,53]. An earlier study reported that CW had a stable reduction percentage for Chla (58 to 73%) in aquaculture pond water [10].…”

“…Excessive phytoplankton, especially cyanobacteria, can cause poor water quality and have negative effects on fish and shrimps in ponds [51]. It has been confirmed that aquatic macrophytes can inhibit the growth of algae and control algal bloom [52]. The inhibitory effect may be related to competition for nutrients, light and other resources with algae [52,53].…”