Comparative assessment of eutrophication in the southern Black Sea using TRIX, BEAST, and NEAT

This study is among the few that seek to provide an integrated assessment of eutrophication in the coastal region of the Southern Black Sea. Three methods were compared to evaluate eutrophication in the southern Black Sea coastal waters: the Black Sea Eutrophication Assessment Tool (BEAST), the Nested Environmental Status Assessment Tool (NEAT), and the Trophic Index (TRIX). TRIX was not able to effectively differentiate between different levels of eutrophication in the southern Black Sea. Regardless of the assessment method used BEAST and NEAT, all the results indicated that the water quality in the southern Black Sea is either moderate or below. The BEAST and NEAT methodologies demonstrated a stronger correlation with eutrophication-related parameters compared to the TRIX approach. The BEAST assessment typically presented a worst-case scenario compared to NEAT. River-influenced coastal water bodies (CWBs), such as Sakarya (KAR02), Yes,il & imath;rmak (KAR07), and K & imath;z & imath;l & imath;rmak (KAR10) had poor or bad status. Samsun province (KAR08), which has been pressure from both domestic and industrial activities, has been determined to be in a bad status. The study also highlights the critical need for site-specific indicators, reference values, and long-term data for effective assessment tools. The results provide evidence to support managers and decision-makers in monitoring and achieving good environmental status.