Seasonal distribution of plankton diatoms in Lim Bay, northeastern Adriatic Sea

Abstract

The seasonal distribution of planktonic diatoms is presented in relation to the hydrographic and chemical parameters in Lim Bay, a 10 km long fjord-like embayment situated in the north east Adriatic Sea. Water samplings for physicochemical and biological variables were conducted fromMarch 2002 to November 2007 at three stations along the bay. The phytoplankton was dominated by diatoms throughout the year, with the minimum species diversity in summer and the maximum in autumn. A total of 100 diatoms were identified and classified according to their seasonal occurrence in the plankton; some were consistently present throughout the whole year, but a large fraction showed a distinct seasonal cycle. The inner two stations differed significantly in terms of phytoplankton biomass and nutrient content from the outer station, indicating a higher nutrient input in the inner part. The majority of the dominant diatoms recorded in this study prefer nutrient- enriched conditions. Due to the anticipated increase of human impact in the area, this study can serve as a base for future environmental studies in Lim Bay.