Study On The Biodiversity And Taxonomy Of Free-living Marine Nematodes In The Xiamen Island,China

Meiofauna were sampled monthly from January 2011 to December 2011, in the Bathing Beach of Huangcuo and Dadeji. Annual abundance, major groups and horizontal distribution among the different tidal zones and vertical distribution of meiofauna were studied during the periods of investigation. Seasonal structure and biodiversity of free-living marine nematodes community were analysed. The nematodes were classified and identified, besides, the dominant genera were described.Meiofauna in the Bathing Beach of Huangcuo: Annual average abundance of meiofauna were 182.81 ind/10cm2, the highest abundance was in August( 381.63 ind/10cm2), the lowest abundance was in December( 56.51 ind/10cm2). Annual average abundance of the lower intertidal zone was 255.41 ind/10cm2, the middle intertidal zone was 154.11 ind/10cm2, the high intertidal zone was 138.93 ind/10cm2. Vertical distribution of meiofauna nearly equally, slightly increased from surface layer to bottom layer. The most dominant group was free-living marine nematode, accounting for 57.02%, and Copepoda was the second, accounting for 23.94%, besides, annual variation of nematode was much more obvious. Meiofauna in the Bathing Beach of Dadeji: Annual average abundance of meiofauna were 190.11 ind/10cm2,the highest abundance was in June( 322.4 ind/10cm2), the lowest abundance was in January( 62.29 ind/10cm2), Annual average abundance of the lower intertidal zone was 313.07 ind/10cm2, the middle intertidal zone was 137.86 ind/10cm2, the high intertidal zone was 119.39 ind/10cm2, variation presented in some months. Annual average abundance of 0~4cm surface layer was lowest(11.76%), 8~20cm mid-bottom layer was nearly equal. The most dominant group was Copepoda, accounting for 52.73%, and free-living marine nematode was the second, accounting for 31.93%, annual variation of Copepoda was much more obvious.Sampling in the Bathing Beach of Huangcuo: 42 species of marine nematodes were identified in the winter sampling, they belonged to 35 genera, 33 species of marine nematodes were identified in the summer sampling, they belonged to 32 genera, 54 species of marine nematodes were identified in the autumn sampling, and they belonged to 50 genera. Significant seasonal difference of the dominant species, Bathylaimus huanghaiensis was the common dominant species in the winter and autumn, the dominance were 8.97% and 9.70%, respectively, Theristus sp.3 was the common dominant species in the summer and autumn, the dominance were 14.79% and 9.11%. Sampling in the Bathing Beach of Dadeji: 10 species of marine nematodes were identified in the winter sampling, they belonged to 6 genera, 44 species of marine nematodes were identified in the summer sampling, they belonged to 43 genera, 52 species of marine nematodes were identified in the autumn sampling, and they belonged to 46 genera. Latronema sp. was the common dominant species in the winter, summer and autumn, the dominance were 29.79%, 8.52% and 27.92%, respectively, 3 species of Theristus genera and Oncholaimus sp.1 were the common dominant species in the winter and autumn.The similarity of the species was rather low, in the different seasons and intertidal zone in the two beaches, and distribution of nematode community was disperse. 136 species of marine nematodes were identified, they belonged to 111 genera, and in addition, 18 dominant genera were described in this paper. One new species of free-living marine nematodes, Setosabatieria xiamenense sp. nov. from the Xiamen intertidal, Fujian province, are described and illustrated.