A preliminary investigation of phytoplankton of karstic pools (Dugi otok island, Croatia)

Phytoplankton in the karstic pools of Croatian islands has not been investigated in recent times. This paper describes phytoplankton and environmental conditions in three karstic pools on Dugi Otok island (Dalmatia). The pools are small (ca 20 m2) and shallow (max. depth 2 m), with Charophytes and vascular plants covering the bottoms. Eighty-five taxa of net phytoplankton were recorded. These included 22 Cyanobacteria, 14 Chlorophyceae, 17 Charophyceae (Zygnematales), 15 Euglenophyceae, and 17 Bacillariophyceae. Low species richness is owed to the predominance of Cyanobacteria. Despite their similar physicochemical regimes, the pools had different phytoplankton communities. The data presented here contribute baseline information concerning biological diversity, essential for evaluation of environmental changes in the future. Conservation of karstic pools is one way to preserve the overall biodiversity of karstic islands