Dumping of Dredge Spoil in the Pelagic Habitat: Focus on Trophic Status, Phytoplankton Diversity Responses and Generation of Blooms

This study presents the impacts of dredge spoil dumping in pelagic habitat during a 27-month monitoring survey eastern Mediterranean coastal waters (Saronikos Gulf, Aegean Sea), with focus on changes trophic status and eutrophication levels, phytoplankton diversity bloom dynamics. A number environmental parameters metrics were significantly influenced by operations, specifically indices (number species, Diatoms:Dinoflagellates ratio) total abundance, Chlorophyll-a, light transmission, dissolved oxygen inorganic nutrients, N:P ratio, Eutrophication Ιndex (a metric for assessment). Phosphates started to increase after first year shifting ratio values lower than 10. similarity cluster analysis highlighted that community structure pre-dumping early-dumping period was clearly discriminated from operations. clear shift an observed immediately initiation which maximized site two years Diatoms dominated communities, reaching ~ 95% relative abundance site. High biomass producers or potentially toxic diatom species proliferated forming blooms. Pseudo-nitzschia multiseries most frequent species. multivariate (RDA) among suite plotted against stressors relevant dumping, Index, index P. emerged as suitable reflect responses communities dumping. Dredge at sea poses pressures ecosystem components addressed European Marine Strategy Framework Directive (MSFD) programs. In such context, this further supports role blooms sensitive elements assessment management waters.