Growth and Chlorophyll Content of Mangroves in Wetland Mesocosms for the Treatment of Mariculture Effluent

Constructed wetlands represent economically and environmentally viable tools for the control of water pollution, for example through wastewater treatment. In this study, we assessed the growth, morphology, and chlorophyll contents of 3 southern Taiwan native mangrove species (Avicennia marina, Rhizophora stylosa, and Lumnitzera racemosa) planted in monoculture free water surface mesocosms, with respect to different hydraulic residence times (HRTs: 0.5, 1, and 2 d plus 1 drained treatment) and mariculture effluents over a 10-month period in 2007–2008. The seedlings of all 3 mangrove species survived under all mariculture wastewater treatments, but longer HRTs induced greater stress and suppressed mangrove growth. The net primary productivity and the final percent change in leaf number, leaf area, and leaf area ratio of the three mangrove species decreased with increasing HRT. The study concludes that the growth of A. marina was better than that of R. stylosa and L. racemosa under waterlogging conditions with mariculture effluent. Therefore, planting A. marina is suggested as a more appropriate design for seawater mangrove constructed wetland to treat aquaculture wastewater in southern Taiwan.