Glophymed: An index to establish the ecological status for the Water Framework Directive based on phytoplankton in coastal waters

•The Comunitat Valenciana coastal water bodies are subjected to Water Frame Directive.•Phytoplankton is one of the biological quality elements in the directive.•All phytoplankton attributes are developed in a global index for coastal waters.•Anthropogenic pressures related to phytoplankton impacts are included in an index.•The global index determines the ecological status of coastal waters.

Phytoplankton and its attributes (biomass, abundance, composition, and frequency and intensity of phytoplankton blooms) are essential to establish the ecological status in the Water Frame Directive. The aim of this study is to develop an index “Glophymed” based on all phytoplankton attributes for coastal water bodies according to the directive requirements.It is also developed an anthropogenic pressure index that takes into account population density, tourism, urbanization, industry, agriculture, fisheries and maritime transport for Comunitat Valenciana (Spain).Both indexes (Glophymed and human pressure index) based on a multisampling dataset collected monthly during several years, show a significant statistical correlation (r2 0.75 α < 0.01) for typology IIA and (r2 0.93 α < 0.01) for typology III-W. The relation between these indexes provides suitable information about the integrated management plans and protection measures of water resources since the Glophymed index is very sensitive to human pressures.