Study On The Ecology And Taxonomy Of Polycystine Radiolaria From Three Aeras Of The South China Sea

Polycystine radiolarians are exclusively marine, pelagic protists. The ClassPolycystinea comprises two orders, Spumellaria and Nassellaria. The polycystinesare geographically the greatest ranging (pole to pole, surface to abyss) andtaxonomically one of the most diverse of the well-preserved marine planktonicprotozoa. As one of the dominant microfossil groups, they are indicators of marineenvironments and climatic variations.Based on materials collected from surface waters of the South China Sea inNansha Islands in November of1997, off Zhanjiang in1959, and off Shantou in1959and1960. The present study approaches the taxonomy and ecology of the radiolarianfauna of the areas, the results are as following:1. In total,342species were identified, including30were first recorded fromChinese waters. From Nansha Islands, area off Zhanjiang and off Shantou,295,232and167species were found respectively. The species of the order Spumellaria aremore than those of the order Nassellaria in the three areas. Abundances of theSpumellaria are superior to Nassellaria in off Zhanjiang and Shantou waters, but lessthan the abundance of Nassellaria from Nansha Islands.2. The radiolarian fauna from the three areas are tropical and subtropical.3. The results of statistical analysis on the relationships between radiolarians andenviromental factors show that the abundance of radiolarians is positively correlatedwith the water depths, the radiolarian assemblages were identical to the watermasses.4. In Nansha Islands, the abundance of radiolarians in the central part is higherthan those of northeastern regions; the abundances of the layer of0-75m and0-150mare similar. The abundances of radiolarians from areas off Zhanjiang and Shantouincrease gradually from coastal regions to open sea regions with the increasing ofwater temperature and salinity; those in spring and summer are higher than that in winter. The abundance of the polycystines is positively correlated with watertemperature, salinity and depth.5. The Shannon-Wiener diversity index, Species richness index of radiolariansfrom Nansha Islands are higher than those from the areas off Zhanjiang and Shantou.