Satellite-detected early summer coccolithophore blooms and their interannual variability in the Black Sea

Cokacar, T
Oguz, T
Kubilay, N
Interannual variability of the prevalent early summer coccolithophore blooms within surface waters of the Black Sea was studied by means of satellite-based bio-optical observations. Two coccolith detection algorithms, tested for the Black Sea conditions, were found to provide comparable spatial coccolith patterns consistent with the corresponding true color images. Reliability of the algorithms is also supported by several sets of time-series measurements in different parts of the basin. An analysis of 6 year-long series of OCTS and SeaWiFS images from 1997 onwards shows major phytoplankton bloom activity every year in early summer. These blooms are often dominated by dense populations of coccolithophores but with some year-to-year variations in their spatial coverage, intensity, duration and timing of their maximum expanse over the basin. Moreover, limited coccolith coverage noted in the historical CZCS data may imply an increasing contribution of coccolithophores to the summer phytoplankton community from the early 1980s to 1990s. It is consistent with almost an order of magnitude increase in phytoplankton production, and the current view of dramatic shifts in taxonomic composition from diatoms to coccolithophores and dinoflagellates, as a part of transformations that took place in the Black Sea biogeochemistry and ecosystem structure under changing anthropogenic and climate forcing.


The experimental analysis on the Late Quaternary deposits of the Black Sea
Tekiroglu, SE; Ediger, V; Yemenicioglu, S; Kapur, S; Akca, E (Elsevier BV, 2001-01-01)
Holocene sediments taken from the south-eastern and western Black Sea have been investigated in relation to their geochemical, sedimentological and mineralogical characteristics. Their textures are characterized by their low amount of sand, upward-increasing silt and downward-increasing clay contents. While the terrigenous materials transported from Anatolian volcanic-based sources and European alluvial sediments form the shore deposits, the deep-sea sediments mainly consist of the marine biological product...
Parameterization of iron and manganese cycling in the Black Sea suboxic and anoxic environment
Konovalov, S; Samodurov, A; Oguz, T; Ivanov, L (Elsevier BV, 2004-12-01)
New and published data on the distribution and speciation of manganese and iron in seawater are analyzed to identify and parameterize major biogeochemical processes of their cycling within the suboxic (similar to15.6less than or equal tosigma(t)less than or equal tosimilar to16.2) and anoxic layers (sigma(t)less than or equal tosimilar to16.2) of the Black Sea. A steady-state transport-reaction model is applied to reveal layering and parameterize kinetics of redox and dissolution/precipitation processes. Pr...
Density currents in the two-layer flow: an example of Dardanelles outflow
Besiktepe, ST (Elsevier BV, 2003-06-01)
Observations from hydrographic surveys are used to describe the density current flowing through the Dardanelles strait into the Marmara Sea. Aegean water plunges below the surface and flows into the Marmara Sea. This flow joins into the Marmara Sea as a negatively buoyant plume and sinks through the deeper parts. Seasonal variation in the incoming water density results in the observing mainly two different forms of the density current in this area. These two forms are boundary currents and intrusion. Bounda...
Modelling phytoplankton succession on the Bering Sea shelf: role of climate influences and trophic interactions in generating Emiliania huxleyi blooms 1997-2000
Merico, A; Tyrrell, T; Lessard, EJ; Oguz, T; Stabeno, PJ; Zeeman, SI; Whitledge, TE (Elsevier BV, 2004-12-01)
Several years of continuous physical and biological anomalies have been affecting the Bering Sea shelf ecosystem starting from 1997. Such anomalies reached their peak in a striking visual phenomenon: the first appearance in the area of bright waters caused by massive blooms of the coccolithophore Emiliania huxleyi (E huxleyi). This study is intended to provide an insight into the mechanisms of phytoplankton succession in the south-eastern part of the shelf during such years and addresses the causes of E. hu...
The role of mesoscale processes controlling biological variability in the Black Sea coastal waters: inferences from SeaWIFS-derived surface chlorophyll field
Oguz, T; Deshpande, AG; Malanotte-Rizzoli, P (Elsevier BV, 2002-06-01)
Several different time series of chlorophyll images from the 1997-2000 Seaviewing, Wide Field-of-view Sensor data set have been analysed to gain a perspective on the dynamical and biological variability in the Black Sea, particularly oil its northwestern shelf region and along the Anatolian coastal zone. The images are interpreted in terms of documenting the close link between biological production and physical dynamics of the boundary system, and of emphasizing the role of eddy processes on controlling mes...
Citation Formats
T. Cokacar, T. Oguz, and N. Kubilay, “Satellite-detected early summer coccolithophore blooms and their interannual variability in the Black Sea,” DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS, pp. 1017–1031, 2004, Accessed: 00, 2020. [Online]. Available: