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Coccolithophores are an important component of phytoplankton abundance and biomass in the brackish environments of the Black Sea. Here, the abundance, composition, and distribution of coccolithophores were investigated in water samples taken from the first 50 m at 18 stations in the western Black Sea during a coccolithophore bloom, in June 2016. The total cell abundances ranged from 2 to 763 × 104 coccospheres L−1; Emiliania huxleyi was the most dominant species, but also Syracosphaera spp. (S. dilatata and S. molischii), Acanthoica (A. acanthifera and A. quattrospina), and Algirosphaera robusta displayed remarkably high concentrations. The formation of the seasonal thermocline significantly affects the vertical distribution of coccolithophores. Emiliania huxleyi, Syracosphaera spp., and Acanthoica spp. were restricted to the upper part of the water column, whereas high abundances of Algirosphaera robusta occurred below the thermocline. Overall, our results show significant differences in the vertical (ANOSIM R = 0.50, p = 0.0001) and spatial (ANOSIM R = 0.18, p = 0.0006) distribution of coccolithophores. Higher abundances of E. huxleyi and Syracosphaera spp. were recorded in the northwestern inner shelf region when compared to the open-sea samples. The observed coccolithophore spatial distribution is suggested to be mostly associated with the influx of less saline river water with high nutrient concentrations. [ABSTRACT FROM AUTHOR]

Living coccolithophores (LCs) are regarded as a group of calcifiers and play important roles in global carbon cycle. This study used microscopic observations of LCs in the western Pacific Ocean to investigate their community structure and biodiversity, especially to test whether local physical traits (mesoscale eddies) could explain their biogeographic distributions during autumn of 2017. The coccolithophore calcite inventory based on carbon-volume transformation was estimated in this study. A total of 28 taxa of coccospheres and 19 types of coccoliths were identified from 161 samples. Gephyrocapsa oceanica was the most predominant species in all the coccolithophore community, followed by Florisphaera profunda, Emiliania huxleyi, Umbilicosphaera sibogae, Gladiolithus flabellatus and Umbellosphaera tenuis. The abundance of coccospheres and coccoliths ranged from 0 to 26.8×103 cells/L and from 0 to 138.5×103 coccoliths/L, averaged at 4.2×103 cells/L and 10.9×103 coccoliths/L, respectively. This study indicated that coccolithophore community in the survey area can be clustered into four groups. Three ecological niches of coccolithophores were characterized by their vertical profiles and multivariate statistical analysis. Coccolithophore abundance and species composition were remarkably different among warm-eddy region, G. oceanica dominated warm-eddy region, while F. profunda dominated warm-eddy and none-eddy region. The average values of estimated particulate inorganic carbon, particulate organic carbon were 0.197 μg/L and 0.140 μg/L, respectively. The current field study widened the dataset of coccolithophores in western Pacific Ocean. [ABSTRACT FROM AUTHOR]

Coccolithophores are an ecologically and biogeochemically important group of calcifying marine plankton, contributing globally to both the organic carbon pump and the carbonate counter pump. Understanding their distribution in today's ecosystems is crucial for both paleoenvironmental reconstruction and for predicting their fate under climate change and environmental pollution. Traditionally regarded as open ocean dwellers, more recent studies have highlighted their importance in coastal systems. Here we describe the coccolithophore community in the Catalan Sea (Northwestern Mediterranean), off the Ebro River Delta, based on an oceanographic survey conducted in autumn 2019. We identify three environmentally distinct regimes: mixed (mostly shallow), transition (upper photic layers offshore), and stratified deep waters (below 75 m). Total coccolithophore density is driven by Emiliania huxleyi and peaks in the mixed zone where nutrient concentrations are low, but nitrite concentrations are high. We propose that peak cell densities are partly explained by a switch from nitrate to nitrite usage similar to the behavior of diatoms. Species diversity peaks in deeper offshore waters due to vertical stratification. Helicosphaera carteri and Algirosphaera robusta benefit from E. huxleyi decrease both in coastal and offshore environment. • Coccolithophore distribution is described in the Catalan Sea, NW Mediterranean Sea. • E. huxleyi dominates the assemblage and peaks with high nitrite concentrations. • Species diversity peaks in deeper offshore waters due to vertical stratification. • H. carteri and A. robusta benefit from E. huxleyi decrease. [ABSTRACT FROM AUTHOR]

Coccolithophore were collected and analyzed at 10 stations during summer 2010, from coastal and offshore areas off the eastern Libyan coast (southern Mediterranean Sea). The results were compared with oceanographic data. Total coccosphere concentrations, associated with nutrient-depleted stratified waters, show good correlation with the summer data from the central and eastern Mediterranean sites. K-strategist taxa dominate the surface/intermediate water, while Florisphaera profunda is more abundant in the deep photic zone. The canonical correlation analysis reveals that the distribution of coccolithophore taxa is influenced by environmental parameters: K-strategist taxa are related to nutrient-depleted surface/intermediate waters, whereas lower photic zone taxa are influenced by the development of a deep chlorophyll maximum and high salinity values, well below the thermocline. Finally, the occurrence of three clusters above 50 m, between 50 and 100 m, and below 100 m depth can be detected. These results confirm that a vertical species zonation, as a typical feature of low-middle latitude, characterizes the eastern Libyan coast, where the holococcolithophores represent one of the most important features of coccolithophore production during summer. The distribution of F. profunda matches the depth of the DCM layer, once again confirming its use as a proxy of DCM development and paleoproductivity estimates. [ABSTRACT FROM AUTHOR]

The analyses of water and sediment samples, collected at 24 marine stations in a coastal area (Gulf of Gaeta, central Tyrrhenian Sea) during a three year survey (2012–2014), have improved our knowledge of coccolithophore ecology in the Mediterranean neritic domain. A comparison between the results and the oceanographic data has highlighted the ecology of the considered groups, and quantified the relationship between the community structures and the environmental parameters. The coccosphere concentration measured in the Gulf of Gaeta is extremely variable over the sampling periods (min:64 l −1 ; max:2.4*10 5  l −1 ), and comparable with data from other Mediterranean sites. Placolith-bearing taxa are the dominant group of the living communities. The concentration and distribution of Emiliania huxleyi is controlled by the distance from the coast and the Volturno River runoff. The K-strategist taxa are an important component of the summer nannoplankton in the upper 15 m and in the sediment samples. These taxa are also related to summer oligotrophic warm waters and low turbidity as well. The opportunistic behaviour of Helicosphaera carteri is confirmed and is related to moderately elevated nutrient levels and also tolerance to low salinity and terrigenous input. Nevertheless, our findings raise some questions on the reliability of H. carteri as a low salinity proxy. Overall, the sediment assemblages reflect the composition and the temporal distribution of the living communities. The occurrence and distribution of abundant reworked coccoliths, both in water and sediments, provides useful information about coastal dynamics and confirm their use as a reliable runoff proxy. [ABSTRACT FROM AUTHOR]

We present data on distribution patterns of living coccolithophores at 18 selected hydrographic stations, and oceanographic measurements collected at 68 stations during the TIR09 cruise carried out on board of R/V Urania in the southern Tyrrhenian Sea (central part of the Mediterranean Sea) during summer 2009. The survey enabled us to provide indications on the structure of calcareous phytoplankton associations in relation to oceanographic parameters and vertical water column stratification. The total number of coccospheres ranged from < 100 cells l − 1 to ~ 6.8 ∗ 10 4 cells l − 1 (mean 8.28 ∗ 10 3 cells l − 1 ). Emiliania huxleyi dominated the assemblages, followed by Gephyrocapsa spp., small placoliths, Calciosolenia spp., Florisphaera profunda , Holococcolithophores spp., Syracosphaera pulchra and Umbellosphaera tenuis . The coccolithophore community showed a typical vertical zonation, with K-strategist taxa in the upper 75 m and the deep community down to 200 m. The local water circulation and summer stratification significantly affected the spatial and vertical distribution of coccolithophores. [ABSTRACT FROM AUTHOR]

In order to characterize the natural coccolithophore community occurring offshore Azores and to determine their annual and interannual patterns, monthly samples were collected, from September 2010 to December 2014, in the photic zone off Terceira Island. The present study revealed a clear seasonal distribution and a considerable interannual variability of the living coccolithophore community. The highest coccolithophore abundances were observed during spring and winter months, especially due to the smaller species Emiliania huxleyi and Gephyrocapsa ericsonii . In fact, the highest biomass period was registered during April 2011, associated with enhanced abundance of the overcalcified morphotype of E. huxleyi , which was possibly influenced by subpolar waters and subsequent upwelling conditions. The highest abundances of Gephyrocapsa muellerae were recorded during June 2011 and 2014, indicating that this species characterizes the transition between the period of maximum productivity and the subsequent smoother environmental conditions, the first and the later stages of the phytoplankton succession described by Margalef, respectively. During summer to early fall, a gradual decrease of the overall coccolithophore abundance was observed, while the species richness (Margalef diversity index) increased. A subtropical coccolithophore assemblage mainly composed by Umbellosphaera tenuis , Syracosphaera spp., Discosphaera tubifera , Rhabdosphaera clavigera and Coronosphaera mediterranea indicated the presence of surface warmer waters accompanied by reduced mixing and low nutrients concentration. During late fall to winter, the coccolithophore abundance increased again with a concomitant reduction in species diversity. This is potentially linked to low sea surface temperatures, moderate nutrients concentration and surface mixed layer deepening. During 2011, colder and productive waters led to an increase in the total coccolithophore abundances. On contrary, during 2012, characterized by milder environmental conditions, an increase in the diversity of the community was prevalent. The noticeably coccolithophore response to variations in the main physical variables and on main traditional nutrients corroborates the importance of this group as proxy of marine environmental conditions in the past. [ABSTRACT FROM AUTHOR]

Numerous specimens of coccolithophore combination coccospheres in water samples collected from the North Aegean and Tyrrhenian (Mediterranean Sea) have been photographed using the scanning electron microscope.As a consequence a series of taxonomic revisions are proposed, in which the names of the heterococcolithophores and holococcolithophores involved in the same life-cycle are synonymized. This has resulted in synonymizing the genus Coronosphaera with Syracosphaera and establishing one new combination; Syracosphaera arethusae (Kamptner 1941) comb. nov. [ABSTRACT FROM AUTHOR]

The living coccolithophores (LCs) are an important class of calcified taxa of phytoplankton functional groups, and major producers of marine biogenic inorganic carbon, playing an important role in the marine carbon cycle. In this study, we report the two-demensional abundance, composition of LCs and its correlation with the environmental parameters in spring and autumn, in order to understand the ecological role of LCs in the Yellow Sea and the Bohai Sea. In spring, totally 9 taxa belonging to coccolithophyceae were identified using a polarized microscope at the 1 000× magnification. The dominant species were Emiliania huxleyi, Gephyrocapsa oceanica, Helicosphaera carteri, and Calcidiscus leptoporus. The abundance of coccosphores and coccoliths ranged 0-7.72 cells/mL, and 0-216.09 coccoliths/mL, with the average values of 0.21 cells/mL, and 11.36 coccoliths/mL, respectively. The Emiliania huxleyi distribution was similar to Gephyrocapsa oceanica. The highest abundance of coccoliths was observed in the east of Shandong Peninsula in northern Yellow Sea, whereas Helicosphaera carteri distributed more widely. Emiliania huxleyi and Gephyrocapsa oceanica were the two predominant species in LCs with higher abundances. The distribution of LCs was similar to that of coccoliths. In autumn, 14 taxa belonging to coccolithophyceae were identified with dominant species as Emiliania huxleyi, Gephyrocapsa oceanica, Helicosphaera carteri, Calcidiscus leptoporus and Oolithotus fragilis. The abundance of coccosphores and coccoliths ranged 0-24.69 cells/mL, and 0-507.15 coccoliths/mL, with the average values of 1.47 cells/mL, and 55.89 coccoliths/mL, respectively. The highest abundance of coccoliths was located in Qingdao coastal waters and south of the survey area. The distribution of LCs was similar to the coccoliths; in addition, LCs presented large abundance in the east of the central Yellow Sea area. [ABSTRACT FROM AUTHOR]

This paper presents a first attempt to characterize coccolithophore assemblages occurring in the context of an active submarine canyon. Coccolithophores from the upper-middle sections of the Nazaré Canyon (central Portuguese margin) – one of the largest canyons of the European continental margin – were investigated during a late winter period (9–12 March 2010). Species distributions were analyzed in a multiparameter environmental context (temperature, salinity, turbidity, Chl-a and nutrient concentrations). Monthly averaged surface water Chl-a concentrations between 2006 and 2011 assessed from satellite data are also presented, as a framework for interpreting spatial and temporal distribution of phytoplankton in the Nazaré Canyon. The Nazaré Canyon was observed to act as a conduit for advection of relatively nutrient-poor oceanic waters of ENACWst origin into nearshore areas of the continental shelf (less than 10km off the coast), whilst at the surface a nutrient-rich buoyant plume resulting from intensive coastal runoff prior and during the beginning of the cruise was spreading in oceanward direction. Two distinct coccolithophore assemblages appear representative for the coast to open-ocean gradient: (1) Emiliania huxleyi together with Gephyrocapsa ericsonii and Coronosphaera mediterranea dominated the more productive assemblage present within coastal-neritic surface waters; and (2) Syracosphaera spp. and Ophiaster spp. displayed a higher affinity with open-ocean conditions, and also generally a broader vertical distribution. Local “hotspots” of coccolithophore and phytoplankton biomass potentially associated with perturbations of surface water circulation by the canyon are discussed. [ABSTRACT FROM AUTHOR]

Coccolithophores were used as sensitive indicators for the present-day functioning of the Java upwelling area to better understand the key role of this region in the tropical Indian Ocean dipole mode. Sampling was conducted during the oligotrophic phase of the monsoonal cycle. At all sites low abundance coccolithophore communities were found with surface assemblages either dominated by Gephyrocapsa oceanica or Umbellosphaera irregularis or a diverse mixture including the two named species plus Palusphaera vandelii, Ophiaster hydroideus, Syracosphaera spp. and Calciosolenia spp. with no clear dominance of a single species. Below a well defined thermocline a deep-photic community was dominated by Florisphaera profunda, but also with high abundances of Algirosphaera robusta, Gladiolithus flabellatus and Oolithotus antillarum. In the sediments only 19 taxa were found with the three species F. profunda, G. oceanica, and E. huxleyi making up more than 90% of the assemblages. The observed living communities were part of the recurrent seasonal cycle and corresponded to the environmental conditions. The sediment assemblages distinctly differ from the living communities. Alteration effects appeared to be strong but were probably not the only cause for the biases between the living communities and the sediment assemblages. The communities during ongoing upwelling also significantly contributed to and determined the sedimentary assemblage. [Copyright &y& Elsevier]