Τhe Marine Ecosystem and the Anthropogenic Impacts in the South Evvoikos Gulf: Central Aegean Sea

2022 ◽  
Author(s):  
Ioanna Siokou ◽  
Christos Anagnostou ◽  
Vasiliki-Angeliki Catsiki ◽  
Olympia Gotsis-Skretas ◽  
Ioannis Hatzianestis ◽  
...  
Keyword(s):  
Anthropogenic Impacts ◽  
Marine Ecosystem ◽  
Aegean Sea ◽  
The South

Late quaternary bottom-current activity in the south Aegean Sea reflecting climate-driven dense-water production

2016 ◽  
Vol 375 ◽  
pp. 99-119 ◽  
Author(s):  
Efthymios K. Tripsanas ◽  
Ioannis P. Panagiotopoulos ◽  
Vasilios Lykousis ◽  
Ioannis Morfis ◽  
Aristomenis P. Karageorgis ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Aegean Sea ◽  
Bottom Current ◽  
Water Production ◽  
The South ◽  
Dense Water ◽  
Current Activity

scholarly journals Poseidon: A marine environmental monitoring, forecasting and information system for the Greek seas

2000 ◽  
Vol 1 (1) ◽  
pp. 71 ◽  
Author(s):  
T.H. SOUKISSIAN ◽  
G. CHRONIS
Keyword(s):  
Marine Ecosystem ◽  
Coastal Zone Management ◽  
Aegean Sea ◽  
Sea Transport ◽  
Marine Research ◽  
Zone Management ◽  
Operational Oceanography ◽  
Monitoring And Forecasting ◽  
Forecasting System ◽  
Marine Environmental

The scope of this work is twofold: i) to discuss and analyze some principles, issues and problems related to the development and advancement of Operational Oceanography in Greece and ii) to present a real-time monitoring and forecasting system for the Aegean Sea, which is currently under implementation. Operational Oceanography in Greece has become a necessity today, since it can provide aid to find solutions on problems related to societal, economic, environmental and scientific issues. Most of the Greek coastal regions are under pressure, susceptible to damages due to the increasing tendency of the population to move from the inland to the coast, marine environmental pollution, competitive development of the coastal market sector, etc. Moreover, the complex geomorphology of the coastal areas and the interdependence between natural processes and human activities causes significant alterations in this delicate environment. A rational treatment of these problems can be based on integrated coastal zone management (ICZM). An absolutely necessary means for establishing ICZM is the operation of marine moni- toring systems. Such a system ("POSEIDON system") is under implementation by the National Centre for Marine Research. POSEIDON is a comprehensive marine monitoring and forecasting system, that aims to improve environmental surveillance and facilitate sea transport, rescue and safety of life at sea, fishing and aquaculture, protection of the marine ecosystem, etc. POSEIDON is expected to enhance considerably the capabilities to manage, protect and develop the marine resources of the Greek Seas and to promote Greek Operational Oceanography.

scholarly journals Key Environmental Factors Controlling Planktonic Foraminiferal and Pteropod Community’s Response to Late Quaternary Hydroclimate Changes in the South Aegean Sea (Eastern Mediterranean)

2020 ◽  
Vol 8 (9) ◽  
pp. 709
Author(s):  
Christina Giamali ◽  
George Kontakiotis ◽  
Efterpi Koskeridou ◽  
Chryssanthi Ioakim ◽  
Assimina Antonarakou
Keyword(s):  
Environmental Factors ◽  
Environmental Changes ◽  
Late Quaternary ◽  
Eastern Mediterranean ◽  
Planktonic Foraminifera ◽  
Explanatory Power ◽  
Principal Component ◽  
Aegean Sea ◽  
Late Glacial ◽  
The South

A multidisciplinary study was conducted in order to investigate the environmental factors affecting the planktonic foraminiferal and pteropod communities of the south Aegean Sea. Aspects of the Late Quaternary paleoceanographic evolution were revealed by means of quantitative analyses of planktonic foraminiferal and pteropod assemblages (including multivariate statistical approach; principal component analysis (PCA)), the oxygen (δ18O) and carbon (δ13C) isotopic composition of planktonic foraminifera and related paleoceanographic (planktonic paleoclimatic curve (PPC), productivity (E-index), stratification (S-index), seasonality) indices, extracted by the gravity core KIM-2A derived from the submarine area between Kimolos and Sifnos islands. Focusing on the last ~21 calibrated thousands of years before present (ka BP), cold and eutrophicated conditions were identified during the Late Glacial period (21.1–15.7 ka BP) and were followed by warmer and wetter conditions during the deglaciation phase. The beginning of the Holocene was marked by a climatic amelioration and increased seasonality. The more pronounced environmental changes were identified during the deposition of the sapropel sublayers S1a (9.4–7.7 ka BP) and S1b (6.9–6.4 ka BP), with extremely warm and stratified conditions. Pteropod fauna during the sapropel deposition were recorded for the first time in the south Aegean Sea, suggesting arid conditions towards the end of S1a. Besides sea surface temperature (SST), which shows the highest explanatory power for the distribution of the analyzed fauna, water column stratification, primary productivity, and seasonality also control their communities during the Late Quaternary.

Holocene climatic and palaeoenvironmental changes in the South-Eastern Barents Sea – new insights from palaeomagnetic and geochemical stratigraphy

2020 ◽  
Author(s):  
Martin Klug ◽  
Karl Fabian ◽  
Jochen Knies ◽  
Valérie Bellec ◽  
Leif Rise
Keyword(s):  
North Atlantic ◽  
Remanent Magnetization ◽  
Late Holocene ◽  
Environmental Changes ◽  
Barents Sea ◽  
Marine Ecosystem ◽  
Planetary Science ◽  
Coastal Current ◽  
The South ◽  
South Eastern

<p>Holocene climate variability and environmental changes have been studied using a sediment record from the Barents Sea with focus on the spatio-temporal evolution of bio-productivity and terrestrial sediment deposition in response to changes of climate and regional oceanography. From a 3 m long sediment core recovered in the South-Eastern Barents Sea at 72.5°N 32.5°E u-channels were extracted and stepwise demagnetized and measured for their natural remanent magnetization (NRM) and anhysteretic remanent magnetization (ARM) at the cryogenic magnetometer facility at the Geological Survey of Norway. The u-channel measurements at 3 mm resolution allow the reconstruction of palaeoinclination, relative declination and relative palaeointensity. Comparison of these parameters to FENNOSTACK (Snowball et al., 2007) and EGLACOM-SVAIS (Sagnotti et al., 2011) establishes a robust age model for the sediment sequence which otherwise contains little datable material. We applied statistical factor analysis as centred logratio (clr) transformation to reduce dimensionality of the XRF data and compare changes in high-resolution magnetic susceptibility, wet bulk density and XRF elemental composition with changes of climate proxies in other North Atlantic sedimentary records.</p><p>Based on the new chronostratigraphic framework changes of inorganic and organic proxies at long-term and sub-millennial scale resolve the temperature variability throughout the Holocene. Calcium content changes are related to regional bio-productivity changes in response to surface temperature changes with a pronounced deterioration at the beginning of the Neoglaciation and gradual enhancement during the late Holocene. Besides palaeoclimatic responses, the results offer the opportunity to study sediment transport and deposition during the regional deglaciation and mid-Holocene glacier growth in northwestern Fennoscandia. The temporal changes of the regional oceanography and the variability of marine palaeoproductivity in the South-Eastern Barents Sea indicate an active interplay between the North Atlantic Current (NAC) and the Norwegian Coastal Current (NCC) during the early Holocene, a predominance of the NCC during middle Holocene and a re-amplification of the NAC during the late Holocene. Comparison to other records from the Nordic Seas enables the reconstruction of responses and the vulnerability of this arctic marine ecosystem to past climate variations and may help to estimate upcoming responses to recent and future climate changes.</p><p> </p><p>References:</p><p>Snowball, I., L. Zillén, A. Ojala, T. Saarinen, and P. Sandgren (2007), FENNOSTACK and FENNORPIS: Varve dated Holocene palaeomagnetic secular variation and relative palaeointensity stacks for Fennoscandia, Earth and Planetary Science Letters, 255, (1-2), 106–116</p><p>Sagnotti, L., P. Macrì, R. Lucchi, M. Rebesco, and A. Camerlenghi (2011), A Holocene paleosecular variation record from the northwestern Barents Sea continental margin, Geochemistry, Geophysics, Geosystems, 12, (11)</p>

A synthesis of the circulation and hydrography of the South Aegean Sea and the Straits of the Cretan Arc (March 1994–January 1995)

1999 ◽  
Vol 44 (4) ◽  
pp. 469-509 ◽  
Author(s):  
Alexander Theocharis ◽  
Efstathios Balopoulos ◽  
Soterios Kioroglou ◽  
Harilaos Kontoyiannis ◽  
Athanassia Iona
Keyword(s):  
Aegean Sea ◽  
The South

Emplacement of the Miocene west Naxos pluton (Aegean Sea, Greece): a structural study

2003 ◽  
Vol 140 (1) ◽  
pp. 45-61 ◽  
Author(s):  
IOANNIS K. KOUKOUVELAS ◽  
SOTIRIOS KOKKALAS
Keyword(s):  
Aegean Sea ◽  
Biotite Granite ◽  
Distribution Analysis ◽  
Block Rotation ◽  
The South ◽  
Mafic Enclaves ◽  
The North ◽  
Divergent Flow ◽  
Regional Deformation ◽  
Fry Method

Synmagmatic and solid-state structures within the Naxos pluton and its rim may provide insight into the interplay between plutonism and regional deformation at upper-crustal level. Within the hornblende–biotite granite of western Naxos, synmagmatic foliations display two distinct patterns, onion-skin in the north and tangential to the rim in the south. The two areas are separated by the NE-trending Glinadon fault. Deformed mafic enclaves in the pluton are prolate, with their long axes parallel to the synmagmatic lineation. In contrast, phenocryst distribution analysis, using the Fry method, defines an apparent oblate strain with a horizontal stretching lineation. Planar markers within the pluton progressively steepen through the vertical at the east pluton border. Several lines of evidence, such as dykes intruding axial areas of rim-parallel folds, foliated or folded aplite veins, folds and spaced cleavage in the mollase, and inverted stratigraphy, suggest pluton emplacement and deformation during transpressional deformation. A northward divergent flow regime with magma spreading out mainly from the Naxos fault, and the deflection of both the synmagmatic foliation pattern and the flow lines at the Glinadon fault, suggest that the NE–SW- and N–S-trending faults were active during pluton formation. In the south the pluton has grown by the expansion of dykes occupying P-shear positions with respect with the Naxos fault; in the north a piecemeal block down-drop complements this process and favours voluminous magma concentration. During the late evolutionary stages of pluton construction, the magma chamber was compartmentalized into NE-trending sectors affected by block rotation in an anticlockwise manner. Understanding the role of faults in the emplacement of the Naxos pluton is important for understanding emplacement of other plutons in the Aegean Sea region, since most of them are controlled by N–S- (Ikaria pluton) or NE- (Tinos, Serifos and Delos plutons) trending faults.

scholarly journals Sea urchin response to rising pCO2 shows ocean acidification may fundamentally alter the chemistry of marine skeletons

2014 ◽  
Vol 15 (3) ◽  
pp. 510 ◽  
Author(s):  
L. BRAY ◽  
M.A. PANCUCCI-PAPADOPOULOU ◽  
J. M. HALL-SPENCER
Keyword(s):  
Ocean Acidification ◽  
Species Interactions ◽  
Sea Urchins ◽  
Marine Ecosystem ◽  
Aegean Sea ◽  
Paracentrotus Lividus ◽  
Low Ph ◽  
Reference Sites ◽  
Coastal Systems ◽  
Arbacia Lixula

Ocean acidification caused by an increase in pCO2 is expected to drastically affect marine ecosystem composition, yet there is much uncertainty about the mechanisms through which ecosystems may be affected. Here we studied sea urchins that are common and important grazers in the Mediterranean (Paracentrotus lividus and Arbacia lixula). Our study included a natural CO2 seep plus reference sites in the Aegean Sea off Greece. The distribution of A. lixula was unaffected by the low pH environment, whereas densities of P. lividus were much reduced. There was skeletal degradation in both species living in acidified waters compared to reference sites and remarkable increases in skeletal manganese levels (P. lividus had a 541% increase, A. lixula a 243% increase), presumably due to changes in mineral crystalline structure. Levels of strontium and zinc were also altered. It is not yet known whether such dramatic changes in skeletal chemistry will affect coastal systems but our study reveals a mechanism that may alter inter-species interactions.

Normal faulting on Sifnos and the South Cycladic Detachment System, Aegean Sea, Greece

2011 ◽  
Vol 168 (3) ◽  
pp. 751-768 ◽  
Author(s):  
Uwe Ring ◽  
Johannes Glodny ◽  
Thomas M. Will ◽  
Stuart Thomson
Keyword(s):  
Aegean Sea ◽  
Normal Faulting ◽  
The South

scholarly journals Structure, tectonic processes and deformation of the South Aegean Sea

2021 ◽  
Author(s):  
Κωνσταντίνα Τσαμπουράκη-Κραουνάκη
Keyword(s):  
Aegean Sea ◽  
The South ◽  
Tectonic Processes ◽  
Back Arc

Η παρούσα διατριβή διερευνά τη μακροχρόνια παραμόρφωση και τους ενεργούς τεκτονικούς μηχανισμούς που συνέβαλαν στην εξέλιξη και στο σχηματισμό του πολύπλοκου ανάγλυφου του Νοτίου Αιγαίου. Παρά τις γεωλογικές έρευνες που έχουν διεξαχθεί στο Αιγαίο, μέχρι και σήμερα γνωρίζουμε πολύ λίγα για τη γεωδυναμική εξέλιξη του. Αν και είναι ευρέως αποδεκτό ότι στη γεωτεκτονική εξέλιξη της μικρο-πλάκας του Αιγαίου κυριαρχούν κυρίως οι εφελκυστικές διεργασίες παραμόρφωσης που συναντώνται σε ένα back-arc περιβάλλον (οπισθοτόξο), πρόσφατες γεωλογικές, σεισμολογικές και γεωδαιτικές μελέτες έχουν δείξει ότι η συνολικός εφελκυσμός δύναται να περιλαμβάνει και πλαγιό-συμπιεστικές και πλαγιό- εφελκυστικές διεργασίες. Η παρούσα διπλωματική εργασία συνοψίζει την προϋπάρχουσα βιβλιογραφία και τα κύρια μοντέλα παραμόρφωσης που έχουν προταθεί για το Αιγαίο και μέσω της παρουσίασης νέων βαθυμετρικών και σεισμικών δεδομένων στοχεύει στη βελτίωση της κατανόησης των τεκτονικών διεργασιών και των παραμορφώσεων που επικρατούν στο Νότιο Αιγαίο. Προκειμένου να αναπτυχθεί ένα γεωδυναμικό μοντέλο που θα εξηγεί τις κινηματικές διεργασίες και τους μηχανισμούς παραμόρφωσης που έλαβαν χώρα στην περιοχή, ο κύριος άξονας της διατριβής δομείται από τρεις κύριες ερευνητικές εργασίες, τα αποτελέσματα των οποίων παρέχουν νεότερες πληροφορίες για τη γεωδυναμική εξέλιξη του Νοτίου Αιγαίου.

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