Spatiotemporal variations of benthic macrofaunal community in the Xiamen Amphioxus Nature Reserve, eastern South China Sea

In order to realize the spatiotemporal variations of benthic macrofaunal communities at the"Amphioxus Sand"habitat,six surveys including four seasons and three consecutive summers(i.e.,2014,2015 and 2016)were conducted in two core sites,i.e.,Huangcuo(HC)and Nanxian-Shibaxian(NX),in the Xiamen Amphioxus Nature Reserve in China.A total of 155 species of macrofauna were recorded,therein,polychaetes were dominant in terms of species number and density.Significant spatiotemporal variations of macrofaunal communities were observed.The density of polychaetes and the biomass of molluscs in the HC site were higher than those in the NX site.Macrofauna were more diverse and abundant in the cold seasons(winter and spring)than that in the warm seasons(summer and autumn).The annual variations of macrofaunal communities may be attributed to the changes in sediment texture among the three years of the survey.The variations in macrofaunal communities were mainly related to the proportion of polychaetes within the community.In addition,the density of amphioxus(include Branchiostoma japonicum and B.belcheri)was negatively correlated to that of polychaetes,bivalves,and crustaceans.Amphioxus was less likely to be found in the sediments with higher silt and clay content.Five biotic indices including Margaref’s richness index(d),Peilou’s evenness index(J′),Shannon-Wiener diversity index(H′),AMBI and M-AMBI were calculated in the present study.AMBI seems suitable in assessing benthic health at the"Amphioxus Sand"habitat,and a potential risk of ecological health in Xiamen Amphioxus Nature Reserve should be aware.

Removal of Herbicides from Water Using Heterogeneous Photocatalysis Case Study: MCPA Sodium Monohydrate

In this study, the herbicide MCPA sodium salt monohydrate (sodium (4-chloro-2 methylphenoxy) acetate has been studied as are presentative compound used in the agricultural field. Accordingly, direct photolysis and photocatalytic experiments under artificial irradiation simulating solar light in laboratorial conditions were performed. Photocatalytic experiments were performed using TiO2 dispersed powder and as an immobilized thin layer on the surface of blue glasses. The obtained results of photolysis showed a poor efficacy toward degradation of MCPA sodium monohydrate, with half-life (t1/2) 6931.5 min. While, the addition of TiO2 dispersed powder to the photocatalytic process enhances the process dramatically with (t1/2) equal to 36.5 min;furthermore, complete mineralization had been reached after approximately 4 hours, whereas the addition of TiO2 through immobilized system led to enhance the degradation rate with 2236 min. as t1/2. In spite of this, using TiO2 supported on glass substrates with more improvements could be a promising alternative to conventional TiO2 suspension, and provides a clean treatment method.