title: Seasonal variability of phytoplankton at Varna Bay (Black Sea).
abstract: Intrinsic fluorescence and SDS-PAGE analysis were employed to study the seasonal qualitative and quantitative changes of phytoplankton composition at Varna Bay (Black Sea). Variation in the maximum emission wavelength (lambda(max)) of the phytoplankton proteins (398 nm in the summer and 340 nm in the spring) was observed. In addition, a decrease in fluorescence intensity, and a shift in lambda(max) as a result of changes in phytoplankton protein stability, according to the season, was noted. Similarly, SDS-PAGE analysis showed different protein patterns for each season, for example in summertime the major protein constituents were of 14, 37, 48 and 70 kDa, while in the springtime the sizes ranged between 38 and 48 kDa. In general, higher carbohydrate and protein contents correlated with larger phytoplankton biomass found during the summer. The dominant species, the Bacillariophyceae and Dinophyceae, were found to be present in the water body in an alternate pattern. All of these changes could be accounted for by the adaptation of the organism to seasonal variations that modify the sea environment at Varna Bay.
authors.affiliation: Institute of Oceanology, Department of Biology and Ecology, Bulgarian Academy of Sciences, P.O. Box 152, Varna 9000, Bulgaria.
authors.forename: Snejana
authors.initials: S
authors.lastname: Moncheva
authors.forename: Shela
authors.initials: S
authors.lastname: Gorinstein
authors.forename: Galina
authors.initials: G
authors.lastname: Shtereva
authors.forename: Fernando
authors.initials: F
authors.lastname: Toledo
authors.forename: Patricia
authors.initials: P
authors.lastname: Arancibia
authors.forename: William A
authors.initials: WA
authors.lastname: Booth
authors.forename: Ivan
authors.initials: I
authors.lastname: Goshev
authors.forename: Moshe
authors.initials: M
authors.lastname: Weisz
authors.forename: Simon
authors.initials: S
authors.lastname: Trakhtenberg
mesh_terms: D002031:Bulgaria; D002241:Carbohydrates / Q000032:analysis* / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D005453:Fluorescence; D010839:Phytoplankton / Q000737:chemistry* / Q000254:growth & development; D010940:Plant Proteins / Q000032:analysis* / Q000302:isolation & purification; D012621:Seasons
chemical_list: D002241:Carbohydrates; D010940:Plant Proteins