Τhe main scope of this book is to illustrate a magnificent marine micro world in eastern Mediterranean Sea waters, the world of Coccolithophores. The eastern Mediterranean Coccolithophores presented in this book have been collected during several cruises and samplings in the Ionian and Aegean Sea at different seasons, between the years 1997-2006. The collected material has been analyzed and photographed by Scanning Electron Microscope and Light Microscope techniques. Αs a result 375 SEM and LM microphotographs are presented together with thorough systematic taxonomy and detailed description of 132 Coccolithophore species. A novelty of this book, compared to traditional atlases, is the trilingual approach of Coccolithophore taxonomy. Each species is described in three languages, English, Greek and Italian. In this way these astonishing beautiful marine microorganisms are getting introduced to a broad public and it becomes easier for non-native English speakers - students and researchers - to get acquainted with the scientific terminology. Additionally the combination of both scanning and light microscope techniques provides the most comprehensive documentation of Coccolithophore species morphology.

Living coccolithophores were collected in August 2001, at different photic depths (0-120 m), form 8 stations along a transect in the gulf of Korthi (Andros island). The analysis of the vertical distribution of coccolithophores certified high differentiation in density and diversity, as well as in the species composition at different depth levels. As a result, the photic zone is separated into three distinct sub-zones: upper (0-25 m depth), middle (45-60 m depth) and lower (90-120 m depth). The total cell density varies between 14.7x103 cells/l and 1.9x103 cells/l, and is usually higher in the upper and middle photic zone, while in the lower photic zone it gradually decreases. The highest species richness (max=34 taxa) was observed at the middle photic zone. Emiliania huxleyi, Rhabdosphaera clavigera and holococcolithophores preferred the upper photic zone. On the contrary, in the lower photic zone, the presence of Florisphaera profunda and Algirosphaera robusta becomes important, making up the typical deep community. Umbellosphaera tenuis is an additional important component of the summer heterococcolithophore nannoflora, especially in the middle photic zone. The studied coastal marine coccolithophore communities indicate that temperature and availability of nutrient concentrations are the most important controlling factors controlling their vertical distribution.

This study concerns the species composition and seasonality of extant coccolithophore communities in Eastern Mediterranean coastal environments and investigates their significance as environmental indicators. Water samples were collected during six one-day cruises carried out between 2001 and 2004, in two separate marine ecosystems (Gulfs of Korthi and Kastro, southeastern coast of Andros Island). High species diversities (65 species of heterococcolithophores and 45 species of holococcolithophores), associated with the dominant K-selected taxa, Rhabdosphaeraceae, and holococcolithophores, were recorded during summer whereas low diversities coupled with maximum concentration of cells and the predominance of r-selected species (Emiliania huxleyi) were observed during late autumn-early spring. The coccolithophores of the upper photic zone have been grouped into four distinct communities (Emiliania huxleyi group, Palusphaera vandelii group, Rhabdosphaera clavigera group and Helladosphaera cornifera group).A taxonomic study of the modern coccolithophores of Aegean Sea is presented. Several combination coccospheres of Algirosphaera robusta with Sphaerocalyptra quadridentata have been well documented, therefore their synonymy is proposed and the remaining species of Sphaerocalyptra have been transferred to the genus Holococcolithophora. One more holococcolith-heterococcolith association between Corisphaera sp. type A, Zygosphaera bannockii, Zygosphaera amoena and Syracosphaera bannockii is presented, recombining all taxa into Syracosphaera amoena comb. nov. A new species, Holococcolithophora kastriensis sp. nov. is described.

Two new possible hetero-holococcolithophore combinations are shown: Syracosphaera histrica withS. pulchra HOL oblonga type and S. molischii with Gliscolithus amitakareniae. In addition, an ambiguous combination of S. pulchra HOL oblonga type with S. pulchra HOL pirus type is recorded by light-microscope imaging. Although represented by ambiguous combinations, they potentially document new life-cycle associations within coccolithophores to add to the complexity of haplo-diplontic coccolithophore stages.