Abstract
To explore the water quality and biodiversity of surface microlayer (SML) in fresh waters, we investigated the water status of
SML and subsurface water (SSW) of three fresh waters in China during April to August of 2010, by chemical and biological
monitoring methods. The results showed that the indexes such as total nitrogen (TN), total phosphorus (TP), chemical oxygen
demand (COD) exceeded the national III or IV level of surface water quality, and the contents of indexes of SML were much
higher than those of SSW (P<0.05, ANOVA). The SML and SSW in the three waters were eutrophic, and the eutrophication of
SML was more serious. It was found out the SML in three waters could seriously enrich to P, N and Chlorophyll a. Moreover, the
species richness and distribution of phytoplankton of SML in three waters were obviously higher than those of SSW, and
Chlorophyta, Bacillarophyta and Cyanophyta became predominant ones. This research shows that SML has the capability of
enrichment to plankton and pollutants such as N, P, which might cause the water quality of SML to be more serious than the
SSW. Meanwhile, higher species richness in SML would not only be regarded as one of indexes of water quality assessment, also
provide a new idea to extract qualities of beneficial micro-biological resources from SML in waters.