Author(s)

K. Torn & G. Martin

Abstract

In this paper water quality assessment system of Estonian coastal sea areas using submerged aquatic vegetation according to the Water Framework Directive of the European Community is described. Estonian coastal waters are divided to 6 national types covering 16 water bodies. The assessment system is based on three monitoring areas for each water body. Three metrics are used for water quality classification system based on phytobenthos: 1) the depth distribution of phytobenthos as the deepest occurrence of a single attached specimen; 2) the maximum depth distribution of Fucus vesiculosus as the deepest occurrence of singe plant specimens; 3) the proportion of perennial plant species in the observed community based on dry biomass of attached erect vegetation. Keywords: classification, coastal water, phytobenthos, water framework directive, ecological quality. 1 Introduction In connection with the implementation of the EU Water Framework Directive (WFD) in the area of assessment of the ecological status of water bodies, the classification system should be developed. Classification systems should be based on different biological water quality elements indicating the status of water bodies. According to the WFD, three biological quality elements (phytoplankton, benthic invertebrate fauna and aquatic flora) should be used for coastal waters [1]. The principle of the whole assessment procedure is to measure deviation from reference condition. According to the normative definition of the WFD, reference conditions represent a status with no or only minor anthropogenic

Keywords

classification, coastal water, phytobenthos, water framework directive, ecological quality.