Preliminary study on the immediate response of the nematode community to Typhoon Soudelor

A study of changes in benthic community structure at a station in the East China Sea was conducted before and shortly after the passage of typhoon Soudelor in late June 2003. The results showed that sediment Chl-a and Pheo-a concentrations increased 147.3 and 56.4%, respectively. More significantly, bottom-water oxygen increased at least 8 fold. Macrofauna exhibited no significant density change after the typhoon event but nematode density increased by 61.1% compared to pretyphoon and became numerically higher in the deeper layers of the sediment (increased by 96.9% in the 5-8 cm section). Wind mixing, resuspension, and sinking resulting from the typhoon passage probably were the major processes inducing these phenomena. Both nematode assemblage composition and biodiversity were less affected by the typhoon disturbance. However, the nematode trophic composition changed to some extent after the typhoon, suggesting an increase in epigrowth feeders on renewed primary producers. Further studies are still required to discover the primary forcing mechanisms.