Insights into assessing environmental quality status using potential surrogates of biofilm-dwelling ciliate fauna in coastal waters

Abstract

To determine potential surrogates of biofilm-dwelling ciliate fauna for assessing water quality, a dataset of coastal waters of the Yellow Sea was studied. Samples were collected monthly at a depth of 1 m from four sampling stations during a 1-year cycle (August 2011-July 2012), northern China. The ciliate communities at low taxonomic resolutions up to family level were significantly correlated with the full ciliate fauna at species-level resolution and represented a significant spatial variation in relation to the environmental changes. The presence/absence resolutions up to genus level maintained sufficient information of the ciliate species-abundance matrix. The vagile and sessile ciliate assemblages were significantly correlated with the full ciliate communities but only the latter maintained sufficient information with a significant spatial variation in response to the environmental stress. Correlation analyses showed that the taxon richness indices of potential surrogates at genus- and family-level resolutions can explain >95 % of the variance in that of the full species pool. Thus, it is suggested that the taxonomic resolutions up to family level may be a robust time-efficient surrogate of whole periphytic ciliate communities for assessing water quality status and would allow improving sampling strategies of large spatial scale monitoring programs, using biofilm-dwelling ciliates, in coastal waters.