Zooplankton of eastern black sea (Trabzon coastline) and seasonal changesin fatty acid composition of zoopolankton

Temporal variation in total lipid amount and fatty acids, of zooplankton abundance and their interaction with environmental parameters in the Eastern Black Sea were studied. Copepoda was the most dominant (56 %) in zooplankton. Noctiluca scintillans (30 %) and cladocera (11 %) fallowed with copepoda. It was identified that between the abundance of zooplankton and chlorophyll-a was a negative relationship.Maximum total lipid amount was for Calanus euxinus and Pileurobrachia pileus in February (respectively; 7.02%, 1.47 %), for small copepods in January (6.91 %), for Sagitta setosa in April (4.21 %). While the major SFA for copepoda were 16:0 and 14:0, for S. setosa was 18:0 instead of 16:0. In the meantime, the major MUFA for C. euxinus was 16:1 n-7, for other species were 18:1 n-9. DHA and EPA were observed as the major PUFA and amounts of DHA was always higher than amounts of EPA. DHA for P. pileus and S. setosa increased in winter (respectively; 27.87 %, 37.90 %), for C. euxinus in spring (30.97 %), for small copepods in fall (37.77 %). On the other hand, DHA for P. pileus decreased in fall (21.07 %), for S. setosa in spring (32.76 %) and C. euxinus in summer (26.37 %). However seasonal variation was insignificant in EPA (p<0.05). Temperature of surface water varied between 8.84-27.75 oC, including the lowest in March and the highest in August. It was observed that fatty acids of zooplankton species, especially C. euxinus significantly was affected by temperature and of the degree of unsaturation decreased with temperature increace. It was exhibited that variations of total lipid and fatty acid composition were different as zooplankton species and group in the same periods and C. euxinus played an important role what energy transfered the higher levels through fatty acids in Eastern Black Sea food chain. Key words: Zooplankton, Calanus euxinus, fatty acid, DHA, EPA, Eastern Black Sea.