The role of mesoscale processes controlling biological variability in the Black Sea coastal waters: inferences from SeaWIFS-derived surface chlorophyll field

• Published in: Continental shelf research Vol. 22; no. 10; pp. 1477 - 1492
• Main Authors: Oguz, T, Deshpande, A.G, Malanotte-Rizzoli, P
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2002
• Subjects: Biological production; Black Sea; Circulation; Marine; Mesoscale variability; SeaWIFS chlorophyll data; MED, Black Sea; Biological production; Mesoscale variability; SeaWIFS chlorophyll data; Black Sea; Circulation
• ISSN: 0278-4343; 1873-6955
• DOI: 10.1016/S0278-4343(02)00018-3

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 on 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 mesoscale chlorophyll distributions. It is shown that western coastal waters of the Black Sea are characterized by permanently high chlorophyll concentrations of more than 4.0 mg m −3, often subject to considerable dynamical transformations, and modulated by mesoscale structures including southward elongated filament-like features extending up to 100 km offshore with a lifetime of up to a month. Filaments, meanders, offshore jets and other forms of mesoscale and sub-mesoscale structures appear as a common signature of the system along the Anatolian coast. They play an important role in the cross-stream transport of biota and chemical constituents, and thus supporting productivity within the interior parts of the basin. The images reveal phytoplankton blooms lasting several months in all three autumn seasons. During autumn 1999 to winter 2000, the phytoplankton biomass declines in December, and then increases to form another bloom in February–March 2000, albeit somewhat weaker. For the previous 2 years (1997, 1998), the autumn bloom is extended towards the first half of the winter but the late winter–early spring bloom is absent.