Response of free-living marine nematodes to the southern Yellow Sea Cold Water Mass

• Free-living marine nematodes were studied in the southern Yellow Sea Cold Water Mass (YSCWM) in June and November 2013.
• Community structure of nematodes had no significant differences in YSCWM between the two seasons, except for the order of dominant species.
• Epigrowth feeders were dominant in terms of species number and abundance in the sampling area.
• Sediment phaeophorbide, bottom water salinity and temperature were the most important factors related to nematode community structure.

The Yellow Sea Cold Water Mass is a remarkable seasonal hydrographic event in the bottom water of the Yellow Sea. In order to reveal the response of free-living marine nematodes to this event, community structure and biodiversity indices of nematodes were studied in June and November 2013. The dominant species were Dorylaimopsis rabalaisi, Spilophorella sp., Daptonema sp., Sabatieria sp. and Parasphaerolaimus sp. In terms of trophic structure, epigrowth feeders were the most dominant group. Correlation analysis showed that Shannon–Wiener diversity index had significantly negative correlation with sediment silt–clay percentage, organic matter content and water content. Results of BIOENV indicated that sediment phaeophorbide content, water content, bottom water salinity and temperature were the most important factors related to nematode community. In conclusion, community structure and biodiversity indices of nematodes were consistent in the two sampling seasons.