Patterns of species and functional diversity of macrofaunal assemblages and the bioassessment of benthic ecological quality status in the southern Yellow Sea.

Macrofauna are useful indicators of benthic ecological quality status, which were studied in summer and autumn of 2020 in the southern Yellow Sea, China. A total of 134 species were identified, and polychaetes represented the most dominant group. The dominant species across both seasons were Ophiura sarsii vadicola, Trigonothracia jinxingae, Heteromastus filiforms, Ninoё palmata, Thyasira tokunagai, Sigambra hanaokai, Ehlersileanira incisa hwanghaiensis, and Portlandia japonica. The average values of macrofaunal abundance and biomass were 386.68 ind./m2 and 28.21 g/m2, respectively. Species diversity during the autumn was slightly higher than that in the summer. Seasonal variations in functional diversity were also observed. BIOENV results indicated that water depth, bottom water temperature, and sediment phaeophorbide content was the optimal combination of parameters to explain macrofaunal assemblage variation. Bioassessment results, based on H', AMBI, and M-AMBI, showed that most sites in the southern Yellow Sea could be classed as moderate or good status.