TY - JOUR TI - Nitrogen as the main driver of benthic diatom composition and diversity in oligotrophic coastal systems AU - Kafouris, S. AU - Smeti, E. AU - Spatharis, S. AU - Tsirtsis, G. AU - Economou-Amilli, A. AU - Danielidis, D.B. JO - Science of the Total Environment, The PY - 2019 VL - 694 TODO - null SP - null PB - Elsevier B.V. SN - null TODO - 10.1016/j.scitotenv.2019.133773 TODO - Biomarkers; Ecosystems; Nitrogen; Nutrients; Phytoplankton, Benthic diatoms; Coastal systems; Cocconeis; Eastern Mediterranean sea; Oligotrophic; Oligotrophic environment; Physicochemical conditions; Temporal and spatial changes, Eutrophication, nitrogen; fresh water; nitrogen, benthos; bioindicator; coastal zone; community composition; concentration (composition); diatom; nitrogen; oligotrophic environment; physicochemical property; species diversity; substrate, Article; biodiversity; biogeographic region; biomass; coastal waters; Cocconeis; concentration (parameter); controlled study; correlational study; diatom; environmental factor; eutrophication; marine environment; nonhuman; nutrient; physical chemistry; phytoplankton; predictor variable; priority journal; sensitivity analysis; taxonomy; water quality; ecosystem; environmental monitoring; Mediterranean Sea; metabolism; microalga; physiology; river, Mediterranean Sea, Bacillariophyta; Cocconeis; Mastogloia, Biomass; Diatoms; Ecosystem; Environmental Monitoring; Eutrophication; Fresh Water; Mediterranean Sea; Microalgae; Nitrogen; Phytoplankton; Rivers TODO - Phytoplankton is the main indicator group for eutrophication in coastal ecosystems, however its high dispersal potential does not enable the assessment of localized effects of coastal nutrient enrichment. Benthic diatoms are sessile microalgae associated with sandy substrates and have the potential to reflect more localized pollution impacts. Although benthic diatoms are widely used bioindicators in freshwater systems, they have rarely been used for assessing the eutrophication status of oligotrophic environments such as the eastern Mediterranean Sea. In the present study, we assess the efficiency of benthic diatoms as bioindicators of nutrient enrichment in oligotrophic coastal systems, by investigating the effect of different physicochemical conditions and nutrient concentrations on the assemblage composition, diversity and individual species populations. To do this, we sampled along a eutrophication gradient formed by anthropogenic nutrient inputs from a metropolitan area. The main driver of assemblage composition, diversity and biomass of diatoms was nitrogen concentration and its temporal and spatial changes. Nitrogen loadings were positively correlated with increased biomass of Cocconeis spp. and negatively correlated with Mastogloia spp. Our findings suggest that in coastal ecosystems of oligotrophic marine ecoregions, benthic diatom assemblage structure and specific taxonomic groups can be reliable predictors of coastal eutrophication offering higher spatial resolution compared to phytoplankton. © 2019 Elsevier B.V. ER -