[Bioturbation of macrobenthos on estuarine sediment].

By using microcosm tracer technique, the bioturbation of macrobenthos Helice tientsinensis, Nereis diversicolor, Bullacta exarata, and Cyclina sinensis on the sediment in Beitang Estuary of Tianjin, China was quantitatively studied. The bioturbation of test macrobenthos had obvious effects on the distribution of the sediment, and the effects differed with the macrobenthos. The disturbed intensity (diffusion coefficient, 10(-3) cm2 x d(-1)) of surface sediment under the effects of the macrobenthos was in order of N. diversicolor (2.95) > H. tientsinensis (1.00) > C. sinensis ( 0.78) > B. exarata. (0.35) > control (0.05), and that of deep sediment was H. tientsinensis (3.10) > N. diversicolor (2.33) > C. sinensis (0.28) > B. exarata (0.15) > control (0.05), which was mainly due to that the macrobenthos were belonged to different functional groups. There was a significant relationship between the bio-volume of test macrobentos and the diffusion coefficient of surface sediment (P < 0.05), suggesting that the bio-volume of macrobenthos could be used as an indicator to predict their bioturbation capacity on esturaine sediment.