Elif Eker-Develi

Distribution of phytoplankton in the southern Black Sea in summer 1996, spring and autumn 1998

The species composition, abundance, and biomass of micro- (>15 μm) and nano- (<15 μm) phytoplankton were studied along the southern Black Sea during June–July 1996 and March–April and September 1998. A total of 150 species were identified, ∼50% of them being dinoflagellates. The average total phytoplankton abundance changed from 77×103 cells l−1 in spring to 110×103 cells l−1 in autumn and biomass from 250 μg l−1 in summer to 1370 μg l−1 in spring. Based on the extensive sampling grid from June–July 1996, phytoplankton seemed to have a rather homogeneous biomass distribution in the southern Black Sea. In all periods, the coccolithophorid Emiliania huxleyi was the most abundant species, its contribution to the total abundance ranging from 73% in autumn to 43% in spring. However, in terms of biomass, diatoms made up the bulk of phytoplankton in spring (97%, majority being Proboscia alata) and autumn (73%, majority being Pseudosolenia calcar-avis), and dinoflagellates in summer (74%, Gymnodinium sp.). There was a remarkable similarity in the dominant species between the western and eastern regions of the southern Black Sea, indicating transport of phytoplankton within the basin.

Increased Chlorophyll Levels in the Southern Caspian Sea Following an Invasion of Jellyfish

A significant correlation was observed between satellite derived chlorophyll a (Chl a) concentrations and the biomass of the invasive comb jellyfish Mnemiopsis leidyi in the southern Caspian Sea. By consuming the herbivorous zooplankton, the predatory ctenophore M. leidyi may have caused levels of Chl a to rise to very high values (∼9 mg m−3) in the southern Caspian Sea. There might also be several other factors concurrent with predation effects of M. leidyi influencing Chl a levels in this region, such as eutrophication and climatic changes which play major roles in nutrient, phytoplankton, and zooplankton variations. The decrease in pelagic fishes due to overfishing, natural, and anthropogenic impacts might have provided a suitable environment for M. leidyi to spread throughout this enclosed basin.

First report of Nitzschia navis-varingica in the Mediterranean Sea and growth stimulatory effects of Nitzschia navis-varingica, Chrysochromulina alifera and Heterocapsa pygmaea on different mammalian cell types

A benthic diatom, Nitzschia navis-varingica was found for the first time in the Mediterranean Sea. Effects of this diatom species together with the haptophyte Chrysochromulina alifera and the dinoflagellate Heterocapsa pygmaea isolated from the northeastern Mediterranean Sea coast on prostate, breast cancer and fibroblast cell lines were investigated. Algal extracts did not exert any toxic effect on these cell lines and it had growth stimulatory impact on the cells without discrimination of cell type. Our results suggest potential use of these algal extracts in tissue repair and cell growth boosting additive in the diet of humans as well as animals. Moreover, these algal extracts have potential to be used as natural resource in the skin vitalizing creams of cosmetics industry and as wound healing agents in the atopic drugs.