scholarly journals Annual Dynamics of Phytoplankton in the Black Sea in Relation to Wind Exposure

2021 ◽  
Vol 9 (12) ◽  
pp. 1435
Author(s):  
Vladimir Silkin ◽  
Alexander S. Mikaelyan ◽  
Larisa Pautova ◽  
Alexey Fedorov

Studies of the annual dynamics of phytoplankton in the NE Black Sea at two stations on the shelf and the continental slope were conducted in 2016, 2017, and 2019. The species composition of phytoplankton has not undergone significant changes compared to previous decades. The coccolithophore Emiliania huxleyi, small flagellates, and diatoms determined the abundance of phytoplankton; and diatoms, coccolithophores, and dinoflagellates determined the total biomass. The annual dynamics of the satellite-derived chlorophyll-a showed peaks in spring and autumn, and sometimes in summer. During the stratified water column period, strong winds in most cases led to a detectible increase in chlorophyll-a. The annual dynamics of phytoplankton followed the pattern: small diatoms (spring) → coccolithophores (late spring, early summer) → large diatoms (summer, autumn). Such a pattern was typical for the previous decades. Coccolithophores dominated in weak SE winds, diatoms in NE winds. The combined effect of sustained offshore wind and strong current can cause diatom blooms during stratified water, even if the wind velocity is moderate.

2002 ◽  
Vol 46 (8) ◽  
pp. 59-66 ◽  
Author(s):  
E. Okuş ◽  
A. Aslan-Yilmaz ◽  
A. Yüksek ◽  
S. Taş ◽  
V. Tüfekçi

As part of a five years monitoring project “Water Quality Monitoring of the Strait of Istanbul”, February-December 1999 nutrient dynamics of the Black Sea-the Sea of Marmara transect are studied to evaluate the effect of discharges given by deep disposals. Through a one-year study, upper layer nutrient concentrations were generally under the effect of northwestern-shelf Black Sea originated waters. This effect was strictly observed in July, when the upper layer flow was the thickest. On the other hand, partly in November but especially in December the northwestern-shelf Black Sea originated water flow was a minimum resulting in similar concentrations in both layers. Nutrient fluctuations also affected the chlorophyll a and POC concentrations as parameters of productivity. The nutrient concentrations decreased with the effect of spring bloom and highest chlorophyll a values were detected in November at Strait stations that did not match to the Sea of Marmara values. This fact represents the time-scale difference between the Black Sea and the Sea of Marmara. On the contrary, high nutrient concentrations in the lower layer (especially inorganic phosphate), and therefore low N:P ratios reflect the effect of deep discharge. Vertical mixing caused by meteorological conditions of the shallow station (M3) under the effect of surface discharges resulted in homogenous distribution of nutrients. Nutrient concentrations of the stations affected by deep discharge showed that the two-layer stratification of the system did not permit the discharge mix to the upper layer.


Author(s):  
Mehmet Özturk ◽  
Cihan Sahin ◽  
Yalcin Yuksel

Ocean currents represent a potentially notable, currently untapped, reservoir of energy. The regions with strong current velocities such as narrow straits connecting two water bodies exhibit high current energy (power) potential especially where the water depths are relatively shallow (EECA, 2009). The Bosphorus, connecting the Black Sea to the Sea of Marmara, is a typical narrow sea strait that generally exhibits a two-layered flow pattern: the upper layer current flows south towards the Sea of Marmara while the underlying current flows in opposite direction towards the Black Sea (Yüksel et al., 2008). The predominant mechanisms for the upper and lower layer flows are the higher water level of the Black Sea and the denser water of the Sea of Marmara, respectively.


1993 ◽  
Author(s):  
Alexander M. Chekalyuk ◽  
Dmitrii K. Bunin ◽  
A. V. Chechendaev ◽  
M. Y. Gorbunov ◽  
D. V. Klimov ◽  
...  

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