Influences of nutritional conditions on degradation of dibutyl phthalate in coastal sediments with Cylindrotheca closterium

In this work, microphytobenthos Cylindrotheca closterium was planted on the surface of coastal sediments to investigate its influence on dibutyl phthalate (DBP) degradation in sediments under different nutritional conditions. The results indicated that C. closterium largely utilized nutrients from the overlying water. Addition of nitrogen, phosphorus or silicon increased algal biomass (as chlorophyll a) by 0.97-3.16, 1.75-2.36 and 1.61-3.09 times, respectively, meanwhile it changed bacterial community structure in sediments with C. dosterium. Growth of C. closterium was more sensitive to nitrogen content in the overlying water. Inoculation of C. closterium increased the relative abundances of dominant aerobic bacteria by 10-67%. Compared with treatments without C. closterium, inoculation of C. closterium increased DBP degradation percentage in sediments (8.5-18.9% increment), which was positively correlated with chlorophyll a content. Thus, microphytobenthos showed the potential for improving the cleansing of polluted coastal sediments, which was obviously related to nutritional conditions in the overlying water.