engleski

Seasonality of Planktonic Diatoms in Telašćica Bay (Middle Adriatic).

Telašćica Bay is located on the SE part of Dugi Otok, an island off Croatia’ s central Adriatic coast. The bay is 8200 m long, varies from 150 to 1500 m in width, and has a total perimeter of about 69 km. The bay’ s striking coastal relief and three distinct parts separated by narrow, shallow passages make it a particularly attractive natural setting. Owing to this and its especially valuable plant and animal life, Telašćica Bay became a protected area in 1980. Phytoplankton samples and hydrographic parameters were collected monthly between November 1999 and October 2000. Samples were taken at the surface using 5-L Niskin bottles at three stations: inland (T1), middle (T2), and outer (T3). Water temperature ranged from 10.3° C (January) to 24.9° C (July), with both the maximum and minimum at T1. Salinity ranged from 37.9 in May to 38.9 in December (both at T2) while dissolved oxygen ranged from 4.9 cm3 L-1 in September at T3 to 6.4 cm3 L-1 in June at T2. Three diatom peaks were noticed. Two, in November 1999 and April 2000, were observed at all stations ; the third peak (October 2000) was found only at T1 and T2. Diatom abundance ranged from 0 to 2 x 104 cells L-1. Although the highest abundance was at T1 (April 2000), diatoms were completely absent from this station in June. The relative contribution of diatoms to total microphytoplankton (with the exception of their absence in samples from June at T1) varied from 0.82 to 96.2%. In November 1999 and April 2000, this was greater than 50% at all stations. Altogether, 43 taxa of planktonic diatoms were identified in Telašćica Bay. Those exceeding 2.5 x 103 cells L-1 were: Chaetoceros curvisetus, C. compressus, Navicula spp., Nitzschia longissima, Pseudo-nitzschia seriata, Thalassionema nitzschioides, and unidentified pennate diatoms. Margalef's species richness index varied among all stations from 0 to 3.6. Higher values were found nearest the open sea.

Phytoplankton; Diatoms; Telašćica; Adriatic Sea

nije evidentirano