scholarly journals Hydrology and circulation in the North Aegean (eastern Mediterranean) throughout 1997 and 1998

2002 ◽  
Vol 3 (1) ◽  
pp. 5 ◽  
Author(s):  
V. ZERVAKIS ◽  
D. GEORGOPOULOS
Keyword(s):  
Surface Layer ◽  
Black Sea ◽  
Sea Water ◽  
Saline Water ◽  
Eastern Mediterranean ◽  
Late Summer ◽  
Cyclonic Circulation ◽  
The Black Sea ◽  
The North ◽  
North Aegean

The combination of two research projects offered us the opportunity to perform a comprehensive study of the seasonal evolution of the hydrological structure and the circulation of the North Aegean Sea, at the northern extremes of the eastern Mediterranean. The combination of brackish water inflow from the Dardanelles and the sea-bottom relief dictate the significant differences between the North and South Aegean water columns. The relatively warm and highly saline South Aegean waters enter the North Aegean through the dominant cyclonic circulation of the basin. In the North Aegean, three layers of distinct water masses of very different properties are observed: The 20-50 m thick surface layer is occupied mainly by Black Sea Water, modified on its way through the Bosphorus, the Sea of Marmara and the Dardanelles. Below the surface layer there is warm and highly saline water originating in the South Aegean and the Levantine, extending down to 350-400 m depth. Below this layer, the deeper-than-400 m basins of the North Aegean contain locally formed, very dense water with different θ /S characteristics at each subbasin. The circulation is characterised by a series of permanent, semi-permanent and transient mesoscale features, overlaid on the general slow cyclonic circulation of the Aegean. The mesoscale activity, while not necessarily important in enhancing isopycnal mixing in the region, in combination with the very high stratification of the upper layers, however, increases the residence time of the water of the upper layers in the general area of the North Aegean. As a result, water having out-flowed from the Black Sea in the winter, forms a separate distinct layer in the region in spring (lying between “younger” BSW and the Levantine origin water), and is still traceable in the water column in late summer.

scholarly journals High resolution simulations on the North Aegean Sea seasonal circulation

2003 ◽  
Vol 21 (1) ◽  
pp. 251-265 ◽  
Author(s):  
V. H. Kourafalou ◽  
K. Barbopoulos
Keyword(s):  
High Resolution ◽  
Sea Water ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Ocean Model ◽  
The Black Sea ◽  
The North ◽  
Seasonal Characteristics ◽  
North Aegean ◽  
North Aegean Sea

Abstract. The seasonal characteristics of the circulation in the North Aegean Sea are examined with the aid of a climatological type simulation (three-year run with perpetual year forcing) on a fine resolution grid (2.5 km by 2.5 km). The model is based on the Princeton Ocean Model with a parameterisation of plume dynamics that is employed for the input of waters with hydrographic properties that are different than the properties of basin waters, as the Black Sea Water (BSW) outflow through the Dardanelles Strait and riverine sources. The model is nested with a sequence of coarser regional and basin-wide models that provide for the long-term interaction between the study area and the Eastern Mediterranean at large. The results are employed to discuss the response of the North Aegean to the important circulation forcing mechanisms in the region, namely wind stress, heat and salt fluxes, buoyancy due to rivers and the BSW outflow (which is low in salinity and occasionally low in temperature) and the interaction with the Southern Aegean. The high resolution allows for the detailed representation of the complicated topography that presides in the region. This helps produce a rich eddy field and it allows for variability in the pathways of BSW that has implications in the basin hydrography and circulation.Key words. Oceanography: general (continental shelf processes; numerical modeling)

scholarly journals Coccolithophore assemblage response to Black Sea Water inflow into the North Aegean Sea (NE Mediterranean)

2017 ◽  
Vol 149 ◽  
pp. 138-150 ◽  
Author(s):  
B.-Th. Karatsolis ◽  
M.V. Triantaphyllou ◽  
M.D. Dimiza ◽  
E. Malinverno ◽  
A. Lagaria ◽  
...  
Keyword(s):  
Black Sea ◽  
Sea Water ◽  
Aegean Sea ◽  
Water Inflow ◽  
The North ◽  
North Aegean ◽  
Ne Mediterranean ◽  
North Aegean Sea

scholarly journals Heterotrophic bacterial growth and substrate utilization in the oligotrophic Eastern Mediterranean (Aegean Sea)

2003 ◽  
Vol 4 (1) ◽  
pp. 23 ◽  
Author(s):  
U. CHRISTAKI ◽  
F.V. WAMBEKE ◽  
M. BIANCHI
Keyword(s):  
Amino Acids ◽  
Black Sea ◽  
Bacterial Growth ◽  
Bacterial Production ◽  
Sea Water ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Substrate Utilization ◽  
The Black Sea ◽  
Respiration Rates

Heterotrophic bacterial growth and substrate utilization were studied in March and September of 1997 in the oligotrophic Aegean Sea. Maximum velocities of ectoproteolytic activity (ectoaminopeptidase ctivity, EAP), as well as amino acid assimilation and respiration rates (AA-A, AA-R) were measured along with bacterial production (protein synthesis). At the northern stations which are influenced by the input of the Black Sea waters, rates at 5 m depth of EAP, AA-A and bacterial production were 2 to 3 times higher than at southern stations. Influenced by the Black Sea water, mean bacterial numbers in the 0-100 m layer showed typical oceanic concentrations averaging 0.7 x 10 6 cells ml -1 . These values, along with low bacterial production rates (30 ng C l -1 h -1 ) implied slow growth for bacteria and/or that a large number among them were inactive. Neither bacterial abundance nor production were correlated with primary production. The percentage of amino acids respired was higher in September compared to March, particularly in the northern Aegean (mean 69 %). The enzyme kinetic analysis showed a biphasic model, the transition between the high and low affinity enzymes being obtained at 50 ΜM. Ectoaminopeptidase activity was weakly correlated with bacterial production (p < 0.05), but strongly correlated with respiration rates of amino acids (p < 0.001), suggesting that the substrate used was devoted to maintain energy requirements.

LONG-TERM MONITORING OF SEASONAL AND INTERANNUAL VARIABILITY OF HYDROLOGICAL STRUCTURE IN COASTAL ZONE OF THE NORTH-EASTERN BLACK SEA

2017 ◽  
Author(s):  
O. Podymov ◽  
O. Podymov ◽  
N. Kuzevanova ◽  
N. Kuzevanova ◽  
A. Khvorosch ◽  
...  
Keyword(s):  
Coastal Zone ◽  
Black Sea ◽  
Hydrogen Sulphide ◽  
Sea Water ◽  
The Black Sea ◽  
Homogeneous Layer ◽  
Marmara Sea ◽  
The North ◽  
North Eastern ◽  
North Eastern Part

The work demonstrates the results of the 6-years complex ship-borne monitoring of coastal zone in the north-eastern part of the Black Sea, carried out by the Southern Branch of P.P.Shirshov Institute of Oceanology, RAS, on a marine cross-section at the Blue Bay (Gelendzhik) beam 1-2 times per month. Climatic changes and eutrophication exert a significant impact on the sea water at the coastal area. In case of the Black Sea these factors pile up with a permanent hydrogen sulphide contamination of the sea water below 80-200 meters depth (depending on the season and distance from the shore). Strong pycno-halocline at the depths from 70 to 160 meters, formed due to the inflow of high salinity water from the Marmara Sea, inhibits the mixing between the water layers and, as a result, also limits the oxygen transport into the deeper layers. The winter cooling reduces the pycno-halocline and enriches the top active layer, down to the cold intermediate layer (CIL), with oxygen and nutrients, which subsequently lead to a vernal phytoplankton bloom. Formation of the thermocline and upper quasi-homogeneous layer (UQL), caused by the water warming in spring, at large extent determines a thickness of phytoplankton-rich layer during the spring and summer seasons. The work demonstrates seasonal and interannual dynamics of the UQL, thermocline, CIL and hydrogen sulphide boundary position in the coastal zone of the north-eastern part of the Black Sea.

scholarly journals Modeling the buoyancy-driven Black Sea Water outflow into the North Aegean Sea

Oceanologia ◽  
2016 ◽  
Vol 58 (2) ◽  
pp. 103-116 ◽  
Author(s):  
Nikolaos Kokkos ◽  
Georgios Sylaios
Keyword(s):  
Black Sea ◽  
Sea Water ◽  
Aegean Sea ◽  
The North ◽  
North Aegean ◽  
North Aegean Sea ◽  
Water Outflow

Variability of mesozooplankton spatial distribution in the North Aegean Sea, as influenced by the Black Sea waters outflow

2009 ◽  
Vol 78 (4) ◽  
pp. 557-575 ◽  
Author(s):  
Ioanna Siokou-Frangou ◽  
Soultana Zervoudaki ◽  
Epaminondas D. Christou ◽  
Vassilis Zervakis ◽  
Dimitrios Georgopoulos
Keyword(s):  
Spatial Distribution ◽  
Black Sea ◽  
Aegean Sea ◽  
The Black Sea ◽  
The North ◽  
North Aegean ◽  
North Aegean Sea

SeaWiFs satellite data analysis of Black Sea water discharge pattern into the Aegean Sea

2002 ◽  
Vol 46 (8) ◽  
pp. 195-202 ◽  
Author(s):  
L. Jönsson
Keyword(s):  
Water Quality ◽  
Black Sea ◽  
Satellite Data ◽  
Sea Water ◽  
Water Discharge ◽  
Aegean Sea ◽  
The North ◽  
Noaa Avhrr ◽  
North Aegean ◽  
North Aegean Sea

Satellite data from the SeaWiFS sensor has been used to determine chlorophyll-a contents in the North Aegean Sea using SEADAS 3.3 software. The data is used to extract knowledge on water movements/flow phenomena using chlorophyll as a “tracer” but will also indicate water quality. More than 100 SeaWiFS scenes from 1998 up to 2001 have been analyzed in terms of hydrodynamic phenomena, mainly the transport and spreading pattern of Black Sea Water in the North Aegean Sea but also concerning the water quality and its seasonal and yearly variation at the mouth region of the Dardanelles. Some comparison with earlier studies using NOAA AVHRR thermal data and historical CZCS scenes is also made.

scholarly journals INTER-annual/decadal variability of the north Aegean Sea hydrodynamics over 1960-2000

2014 ◽  
Vol 15 (4) ◽  
pp. 696 ◽  
Author(s):  
V. VERVATIS ◽  
N. SKLIRIS ◽  
S. S. SOFIANOS
Keyword(s):  
Decadal Variability ◽  
Sea Water ◽  
Salt Content ◽  
Aegean Sea ◽  
The Black Sea ◽  
Minor Role ◽  
Freshwater Flux ◽  
The North ◽  
North Aegean ◽  
North Aegean Sea

Results from a high-resolution hindcast model experiment, supported by available observations, reveal an increasing salinity trend in the north Aegean during the Eastern Mediterranean Transient (EMT), largely controlled by increases in the flow rate and salinity of water masses of Levantine origin entering the domain through the Myconos-Ikaria strait as a response to an acceleration of the Aegean thermohaline cell. Changes in the Dardanelles inflow (increasing salinity) and in the surface freshwater flux (increasing Evaporation-Precipitation), although both contribute to a higher salt content of the basin during the EMT, play a minor role in the inter-annual/decadal variability of the freshwater budget. A long-term decreasing temperature trend is observed from the 1960s to the early 1990s. It is superimposed on the salinity-preconditioning phase over the 1980s and early 1990s. Both signals are, concomitantly, favouring conditions for intense Dense Water Formation (DWF) in the north Aegean Sea. In addition, the northward displacement of the Black Sea Water front over the EMT, leads to the expansion of convective cells towards the north and to higher formation rates associated with both colder and saltier surface waters.

Modelling the impact of Black Sea water inflow on the North Aegean Sea hydrodynamics

2010 ◽  
Vol 60 (3) ◽  
pp. 585-596 ◽  
Author(s):  
Margarita Tzali ◽  
Sarantis Sofianos ◽  
Anneta Mantziafou ◽  
Nikolaos Skliris
Keyword(s):  
Black Sea ◽  
Sea Water ◽  
Aegean Sea ◽  
Water Inflow ◽  
The North ◽  
North Aegean ◽  
North Aegean Sea ◽  
The Impact
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