TREND OF TROPHIC STATE IN NARTA LAGOON

Narta Lagoon, one of the largest and most important coastal ecosystems of Albania, is situated on the south-eastern coast of the Adriatic Sea, northwestern part of Vlora district. It is characterized by a reduced water exchange with sea, a small depth and an intensive evaporation during the dry season. Evaluation of trophic state is based on chlorophyll a content in water and distribution of photosynthetic pigments. The monitored lagoon on different period can be characterized by different trophic state based on the trophic state classification by Hakanson. During monitoring period 2002-2003, Narta lagoon can be characterized by a high trophic state ? eutrophic level, on the first monitoring period during the year 2002. Whereas on the second monitoring during the year 2003, this ecosystem can be characterized by low trophic state evaluated as low mesotrophic level. Trophic state also evaluated in two other periods, 2007 and 2012 was characterized by two different levels evaluated as mesotrophic level and oligotrophic level. The observed differences on the trophic state of selected stations in this lagoon especially its eutrophication can be explain by the communication sea-lagoon, fresh water supply as well as by the pollution near the urban areas.