Toxicologia Ambiental e Analítica

Eutrophication Control by Physical-Ecological Engineering At the Mouth of the Maixi River in Baihua Reservoir

Abstract

Qiuhua Li, Lei Zhang, Chen Fengfeng, Lili Chen and Shulin Jiao

From June 2009 to August 2011, an integrated physical and ecological engineering experiment (PEE) for ecological remediation was conducted in the Maixi river estuary in Baihua Reservoir. An experiment site (EXP) inside, and a reference site (REF) outside, the engineering enclosure were selected. Total nitrogen (TN), total phosphorus (TP), Chlorophyll-a (Chl-a), and chemical oxygen demand (COD) at EXP were significantly lower than at REF; and the greatest differences were 1.00 mg/L, 0.04 mg/L, 23.06 μg/L, and 8.40 mg/L, respectively. Transparency at EXP was dramatically higher than at REF. The trophic index state (TSI) was between oligotrophic and mesotrophic at EXP, between mesotrophic and eutrophic at REF. Phytoplankton abundance in June 2011 was 2100×104 cells/L at REF, but lower at EXP with 33×104 cells/L. Cyanobacteria dominated phytoplankton biomass at both sites, but a higher proportion of diatoms and dinoflagellates was found at EXP. Rotifers were the main estuarine zooplankton. Copepod abundance was significantly different among the sites (p<0.01), with greater abundance at EXP. In general, eutrophication was controlled by the PEE, which could be adjusted to improve water quality.