RESUMO
In order to study the impact of the Yellow Sea cold water mass (YSCWM) on meiofauna, the composition, abundance, biomass of meiofauna and their relationships with environmental variables were analyzed through the samples from 8 stations investigated by R/V 'Dongfanghong II' in June and November, 2013. The results showed that the average abundances of meiofauna were 900.8 and 758.4 ind · 10 cm(-2), and biomasses were 886.9 and 615.7 µg · 10 cm(-2) in June and November, 2013, respectively. Results of ANOVA showed that no significant differences of meiofaunal abundance and biomass were detected among the 8 stations in the two study cruises. A total of 17 meiofaunal groups were identified. The most dominant taxonomic group was free-living marine nematodes, with relative dominance of 88.5% in June and 94.0% in November. The following groups were also important, including benthic copepods, polychaetes, kinorhynchs and ostracods. Analysis of meiofaunal vertical distribution indicated that 92.5% and 95.4% of meiofauna distributed in the top 5 cm of the sediment in the two study cruises, while 59.1% of nematodes and 78.2% of copepods were found in the top 2 cm of the sediment. Correlation analysis among meiofaunal abundance and biomass, nematode and copepod abundance and environmental variables showed that meiofaunal abundance and biomass had significant negative correlations with bottom water temperature (BWT) and sediment silt-clay percentage. Copepod abundance also had significant negative correlations with BWT and silt-clay percentage while it had significant positive correlation with sediment median diameter. The results of BIOENV indicated that BWT, bottom water salinity, sediment water content, sediment chlorophyll a and phaeophorbide contents were the most important factors to influence meiofaunal assemblages.