RÉSUMÉ

New indicators for assessing the ecological state of coastal marine ecosystems on the basis of the basiphyte-epiphyte algosystem (BEAS) are proposed. They include the index of coverage of the basiphyte by epiphytes (P_b/e, %) and the index of the ratio of the basiphyte and epiphyte surface (SI_b/SI_e, units). The results of long-term observations on benthic algae in the NW Black Sea bays (Odessa, Yagorlyksky, and Tendrovsky) and estuaries (Tiligul, Maly Adzhalyk, and Hadzhibeevsky) with different anthropogenic loads were analyzed. Data from BEAS indices were used to develop the indicators (adapted to the requirements of the Marine Strategy Framework Directive) for assessing the ecological status class of marine coastal ecosystems of northwestern part of the Black Sea (NWBS). Scales have been developed and the boundaries of five categories of ecological status classes (high, good, moderate, poor, and bad) have been defined for use in monitoring the aquatic ecosystems of the Ukrainian Black Sea sector. The modern ecological status classes of water bodies of the NWBS, characterized by different anthropogenic load, were established. As a result of the assessment of the ecological state of marine and estuarine water objects of the NWBS using BEAS indices, Yagorlytsky and Tendrovsky bays were found to have reference conditions for NWBS. They were proposed as references for comparison with other water objects of the region.