engleski

Phytoplankton diversity in shallow eutrophic Makirina Cove and Morinje Bay (the eastern Middle Adriatic)

Coastal lagoons are shallow, complex habitats defined by fluctuations in salinity and temperature. Due to its complexity, these rare and endangered types of habitat are protected under directives of European Union, as a part of the Natura 2000 ecological network. Makirina bay and Morinje inlet represent shallow coastal lagoons of the eastern coast of the middle Adriatic, whose sediment floor rich in nutrients, is made of fine, peloid mud. In order to determine the ecological status of two coastal ecosystems investigation of basic physico-chemical parameters, chlorophyll-a and phytoplankton community was conducted during spring and summer season 2018. Detailed analysis of phytoplankton community was assessed in order to determine bioindicators of the ecosystem ecological status. In total, 110 phytoplankton taxa were recorded. The phytoplankton composition in both lagoons did not show significant difference and was dominated by diatoms (up to 6.8  104 cells L-1) and small nano fraction dinoflagellates (up to 5.1  104 cells L-1). The dominance of the dinoflagellate Prorocentrum species suggests eutrophic state of both ecosystems and possible anthropogenic influence. Recorded dinoflagellate Alexandrium implies to the toxicity of the phytoplankton and the need for further toxicological analysis of the ecosystems. Although chlorophyll-a is most commonly used as a bioindicator of coastal water quality, the results of this study indicate that the composition of phytoplankton is a very good indicator of trophic and ecological status of coastal ecosystems and indicates the need to include phytoplankton composition as a standard bioindicator when assessing coastal water status.

bioindicators ; coastal lagoons ; toxic species ; Natura 2000

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