Abstract:Bioturbation is important for biogeochemical processes of sediments. The associations between bioturbation and changes in sediment environment have been well studied. However, little information is available regarding the behavior of the infauna, which is a major factor affecting sediments. In the present study, sediments at the low, middle, and high tidal zones were collected at different depths (above 10 cm: sediments 1#, 2#, and 3#; below 60 cm: sediments 4#, 5#, and 6#) from the natural habitat of Perinereis aibuhitensis Grube to study their choice behavior in two devices (I and II). The contents of organic matter, carbon, nitrogen, and hydrogen sulfide in different sediment types were also examined. In device I, there was no difference in organic matter contents across different sediments (P>0.05). Carbon contents in sediments 1# and 4# were significantly higher than those in sediment 2# (P<0.05). The nitrogen content in sediment 4# was significantly higher than those in sediments 2# and 6# (P<0.05). The contents of hydrogen sulfide significantly differed across different sediments (P<0.05). Hydrogen sulfide concentration in the pore water of sediment 1# was significantly higher than those of other sediments (P<0.05). Two-way analysis of variance showed that different P. aibuhitensis sizes and sediment types had no significant effects on the choice behavior of P. aibuhitensis (P>0.05). Size affected the time to search for different sediments (P<0.05), while sediment type showed no effect on search time (P>0.05). In device II, the content of organic matter in sediment 6# was significantly higher than those of sediments 1# and 2# (P<0.05). The contents of carbon and nitrogen in sediment 6# were significantly higher than those in other sediments (P<0.05). The content of hydrogen sulfide in sediment 2# was significantly higher than that in other sediments (P<0.05), and hydrogen sulfide concentrations in pore water significantly differed among different sediments (P<0.05). Two-way analysis of variance showed that different P. aibuhitensis sizes and sediment types significantly affected the movement distance of P. aibuhitensis (P<0.05). Moreover, small P. aibuhitensis were more active and sensitive and preferred sediments with lower hydrogen sulfide content. When P. aibuhitensis drilled inside the sediment, they tended to choose sediments with lower organic matter content. In general, P. aibuhitensis exhibited a slight selectivity for different natural sediment types.
