scholarly journals Temporal and spatial variability of nutrients and oxygen in the North Aegean Sea during the last thirty years

2014 ◽  
Vol 15 (4) ◽  
pp. 805 ◽  
Author(s):  
Ε. SOUVERMEZOGLOU ◽  
Ε. KRASAKOPOULOU ◽  
A. PAVLIDOU
Keyword(s):  
Deep Water ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Inorganic Nutrients ◽  
Deep Water Formation ◽  
The North ◽  
Deep Waters ◽  
Water Formation ◽  
North Aegean ◽  
North Aegean Sea

Inorganic nutrient and dissolved oxygen data collected in the North Aegean Sea during 1986 - 2008 were analyzed in order to evaluate the role of the inflowing Black Sea originated surface water (BSW) in the nutrient regime of the area.  In periods of high buoyancy inflow from Dardanelles strait, a reduction of inorganic nutrients in the surface layer is observed along the north-west route of the BSW; in parallel, the underlying layer of Levantine intermediate water revealed an increase of inorganic nutrients, receiving the degradation material from the surface layer. The above spatial patterns suggest a contribution of the BSW to the observed enhanced production of the North Aegean Sea. Anomalously low buoyancy inflow of BSW combined with severe winter meteorological conditions promote deep water formation events. The physical and chemical characteristics of the deep waters found in the different basins of the North Aegean Sea in 1997 (following the deep water formation in winters of 1992-1993) differed from those observed after the formation in winter 1987. These differences were probably related to the drastic changes occurred in the deep waters of the Eastern Mediterranean in the early 1990, by the Eastern Mediterranean Transient. Considering that deep water formation processes provide occasionally inorganic nutrients to the euphotic layer, it seems that BSW through its uninterrupted supply of small quantities of nutrients should play an additional role in the production in the North Aegean Sea.

scholarly journals A three dimensional, full life cycle, anchovy and sardine model for the North Aegean Sea (Eastern Mediterranean): Validation, sensitivity and climatic scenario simulations

2021 ◽  
Vol 22 (3) ◽  
pp. 653
Author(s):  
ATHANASIOS GKANASOS ◽  
EUDOXIA SCHISMENOU ◽  
KOSTAS TSIARAS ◽  
STYLIANOS SOMARAKIS ◽  
MARIANNA GIANNOULAKI ◽  
...  
Keyword(s):  
Temperature Increase ◽  
Eastern Mediterranean ◽  
Larval Growth ◽  
Somatic Growth ◽  
Aegean Sea ◽  
Fish Growth ◽  
Prey Concentration ◽  
The North ◽  
North Aegean ◽  
North Aegean Sea

We present the development of a 3D full-lifecycle, individual-based model (IBM) for anchovy and sardine, online coupled to an existing hydrodynamic/biogeochemical low-trophic level (LTL) model for the North Aegean Sea. It was built upon an existing 1D model for the same species and area, with the addition of a horizontal movement scheme. In the model, both species evolve from the embryonic stage (egg+yolk sac larva) to the larval, juvenile, and adult stages. Somatic growth is simulated with the use of a “Wisconsin” type bioenergetics model and fish populations with an adaptation of the ‘super individuals’ (SI) approach. For the reference simulation and model calibration, in terms of fish growth and population biomass, the 2000-2010 period was selected. Interannual biomass variability of anchovy was successfully represented by the model, while the simulated biomass of sardine exhibited low variability and did not satisfactorily reproduce the observed interannual variability from acoustic surveys. The spatial distribution of both species’ biomass was in relatively good agreement with field data. Additional single-species simulations revealed that species compete for food resources. Temperature sensitivity experiments showed that both species reacted negatively to a temperature increase. Anchovy, in particular, was more affected since its spawning and larval growth periods largely overlap with the period of maximum yearly temperature and low prey concentration. Finally, simulation experiments using IPCC climatic scenarios showed that the predicted temperature increase and zooplankton concentration decrease in the future will negatively affect anchovy, resulting in sardine prevalence.

scholarly journals Development, application and evaluation of a 1-D full life cycle anchovy and sardine model for the North Aegean Sea (Eastern Mediterranean)

PLoS ONE ◽  
2019 ◽  
Vol 14 (8) ◽  
pp. e0219671 ◽  
Author(s):  
Athanasios Gkanasos ◽  
Stylianos Somarakis ◽  
Kostas Tsiaras ◽  
Dimitrios Kleftogiannis ◽  
Marianna Giannoulaki ◽  
...  
Keyword(s):  
Life Cycle ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
The North ◽  
Full Life Cycle ◽  
North Aegean ◽  
Full Life ◽  
North Aegean Sea ◽  
Development Application

Temporal Variations in Fine Sand Assemblages in the North Aegean Sea (Eastern Mediterranean)

2004 ◽  
Vol 89 (2) ◽  
pp. 175-187 ◽  
Author(s):  
Evdokia Kourelea ◽  
Dimitrios Vafidis ◽  
Chariton-Charles Chintiroglou ◽  
Georgios Trontsios ◽  
Louis Chicharo
Keyword(s):  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Fine Sand ◽  
Temporal Variations ◽  
The North ◽  
North Aegean ◽  
North Aegean Sea

scholarly journals New Fisheries-related data from the Mediterranean Sea (April 2014)

2014 ◽  
Vol 15 (1) ◽  
pp. 213 ◽  
Author(s):  
K. STERGIOU ◽  
D.C. BOBORI ◽  
F.G. EKMEKÇİ ◽  
M. GÖKOĞLU ◽  
P.K. KARACHLE ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Eastern Mediterranean ◽  
Feeding Habits ◽  
Aegean Sea ◽  
Northern Greece ◽  
Related Data ◽  
The North ◽  
North Aegean ◽  
The Mediterranean ◽  
North Aegean Sea

As part of its policy, Mediterranean Marine Science started from 2014 to publish a new series of collective article with fisheries-related data from the Mediterranean Sea. In this first collective article we present length frequencies and weight-length relationships for the northern brown shrimp Farfantepenaeus aztecus in the eastern Mediterranean, length-weight relationships for 10 fish species in the North Aegean Sea, the feeding habits for 11 sparid fishes in the North Aegean Sea, a review of the existing literature on the feeding and reproduction of common carp Cyprinus carpio in Anatolia (Turkey) and mouth dimensions and the relationships between mouth area and length for seven freshwater fishes from Lake Volvi (Northern Greece).

scholarly journals Lithistid Demosponges of Deep-Water Origin in Marine Caves of the North-Eastern Mediterranean Sea

2021 ◽  
Vol 8 ◽  
Author(s):  
Andrzej Pisera ◽  
Vasilis Gerovasileiou
Keyword(s):  
Deep Water ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Western Mediterranean ◽  
Elevated Concentration ◽  
The North ◽  
Deep Waters ◽  
Marine Caves ◽  
North Eastern ◽  
Tropical Areas

Desmas-bearing demosponges known as lithistids have heavily silicified skeleton and occur typically in bathyal environments of warm and tropical areas but may be found in certain shallow marine caves. Here we report, for the first time two lithistid species, i.e., Neophrissospongia endoumensis, and N. cf. nana, that were earlier known from Western Mediterranean marine caves, from four marine caves in the north-eastern Mediterranean, and their congener Neophrissospongia nolitangere from deep waters (ca. 300 m) of the Aegean Sea. All marine caves, and sections within these caves, where lithistids occur, have freshwater springs. We interpret this surprising association between lithistids and freshwater input by elevated concentration of silica in water in cave sections where such springs occur, being 8–11 times higher in comparison with shallow water outside caves, and comparable to that of deep waters, that promoted lithistids’ development. One of the studied caves harbored an abundant population of N. endoumensis which formed large masses. The age estimation of these lithistids, based on known growth rate of related deep-water sponges, suggest that they could be approximately 769–909 years old in the case of the largest specimen observed, about 100 cm large. These sponges could have colonized the caves from adjacent deep-water areas not earlier than 7,000–3,000 years ago, after the last glaciation, because earlier they were emerged. High variability of spicules, especially microscleres, and underdevelopment of megascleres may be related to silicic acid concentration.

Food-web traits of the North Aegean Sea ecosystem (Eastern Mediterranean) and comparison with other Mediterranean ecosystems

2010 ◽  
Vol 88 (2) ◽  
pp. 233-248 ◽  
Author(s):  
K. Tsagarakis ◽  
M. Coll ◽  
M. Giannoulaki ◽  
S. Somarakis ◽  
C. Papaconstantinou ◽  
...  
Keyword(s):  
Food Web ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Mediterranean Ecosystems ◽  
The North ◽  
North Aegean ◽  
North Aegean Sea

Variability of deep water mass characteristics in the North Aegean Sea: The role of lateral inputs and atmospheric conditions

2012 ◽  
Vol 67 ◽  
pp. 55-72 ◽  
Author(s):  
Yannis S. Androulidakis ◽  
Vassiliki H. Kourafalou ◽  
Yannis N. Krestenitis ◽  
Vassilis Zervakis
Keyword(s):  
Deep Water ◽  
Water Mass ◽  
Aegean Sea ◽  
Atmospheric Conditions ◽  
The North ◽  
North Aegean ◽  
North Aegean Sea

The occurrence of the Atlantic penaeid prawn Farfantepenaeus aztecus (Ives, 1891) in the Thermaikos Gulf (Aegean Sea, eastern Mediterranean): considerations on the potential establishment and impact on the autochthonous Melicertus kerathurus (Forskål, 1775)

Crustaceana ◽  
2014 ◽  
Vol 87 (14) ◽  
pp. 1606-1619 ◽  
Author(s):  
Kosmas Kevrekidis
Keyword(s):  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Western Atlantic ◽  
The North ◽  
Levantine Sea ◽  
Farfantepenaeus Aztecus ◽  
Penaeid Prawn ◽  
North Aegean ◽  
Abiotic And Biotic Factors ◽  
North Aegean Sea

The penaeid prawn Farfantepenaeus aztecus (Ives, 1891), of western Atlantic origin, has been recently recorded in a lagoonal environment in the Thermaikos Gulf (North Aegean Sea) increasing the number of alien decapods in the Aegean Sea to 29. The present work reports the finding of F. aztecus in offshore waters on the trawling ground of the Thermaikos Gulf. The presence of this alien species in the area is probably due to ships’ ballast water or to expansion northward from the Levantine Sea where it was recently reported. The life cycle characteristics and several properties of the Atlantic species along with the abiotic and biotic factors of the Thermaikos indicate that the species will eventually be established successfully in the gulf. However, the potential establishment of F. aztecus in the Thermaikos Gulf raises concerns over the fate of the autochthonous penaeid prawn Melicertus kerathurus (Forskål, 1775) in the North Aegean Sea.

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