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Sample records for aegean sea region

  1. Analytical chemistry in the Aegean Sea region: current status.

    PubMed

    Samanidou, Victoria F

    2012-12-01

    The Eighth Aegean Analytical Chemistry Days Conference took place in Urla, İzmir, Turkey, from 16-20 September 2012. This conference is held every 2 years, organized alternately by analytical chemistry departments of Turkish and Greek universities, so that analytical chemists from the region around the Aegean Sea can exchange experience and knowledge based on their research in a large number of fields. This report summarizes the most interesting presentations and posters pertaining to bioanalytical work.

  2. Variations in fault-slip data and cooling history reveal corridor of heterogeneous backarc extension in the eastern Aegean Sea region

    NASA Astrophysics Data System (ADS)

    Ring, Uwe; Gessner, Klaus; Thomson, Stuart

    2017-03-01

    We report fault-slip data across the boundary between the highly extended and largely submerged crust underlying the Aegean Sea from Samos in the north to eastern Crete in the south, and the much less extended and emergent crust of western Anatolia. We identify three brittle deformation increments, a late Miocene (mainly Pliocene) to Recent crustal stretching increment, an intermittent early to late Miocene shortening increment concurrent with extension and magmatism, and a Miocene extensional event. The youngest increment documents late Miocene to Recent NNE extension over large areas, but can locally also be oriented SE (Amorgos and Astipalea Islands), and ESE (eastern Crete) suggesting overall oblate strain geometry. The intermittent Miocene ( 24-5 Ma) fault-slip records suggest overall prolate strain geometry, where NNE stretching is accompanied by E-W shortening. The older extension event is mainly NNE directed but on Samos Island extension is E-W, probably reflecting local extension in a sinistral wrench corridor in the early/mid Miocene. Overall it seems that since the early Miocene NNE-trending extension is the dominant regime in the eastern Aegean with an intermittent component of short-lived E-W shortening. The existence of a corridor of heterogeneous crustal deformation - which is spatially associated with uncharacteristically old fission track ages - and the apparent change in strain geometry in time challenge concepts that propose that the eastern Aegean Sea and western Anatolia have been deformed as a continuous tectonic domain since the Miocene. We propose that the regional variation in extensional strain geometry resulted from a sinistral wrench component that was superimposed on the regional 'background' NNE extension by translation across a diffuse plate boundary. We conclude that the eastern shoreline of the Aegean Sea is controlled by a Miocene to Recent sinistral wrench corridor that accommodated movement between different lithospheric domains.

  3. Assimilating Ferry Box data into the Aegean Sea model

    NASA Astrophysics Data System (ADS)

    Korres, G.; Ntoumas, M.; Potiris, M.; Petihakis, G.

    2014-12-01

    Operational monitoring and forecasting of marine environmental conditions is a necessary tool for the effective management and protection of the marine ecosystem. It requires the use of multi-variable real-time measurements combined with advanced physical and ecological numerical models. Towards this, a FerryBox system was originally installed and operated in the route Piraeus-Heraklion in 2003 for one year. Early 2012 the system was upgraded and moved to a new high-speed ferry traveling daily in the same route as before. This route is by large traversing the Cretan Sea being the largest and deepest basin (2500 m) in the south Aegean Sea. The HCMR Ferry Box is today the only one in the Mediterranean and thus it can be considered as a pilot case. The analysis of FerryBox SST and SSS in situ data revealed the presence of important regional and sub-basin scale physical phenomena, such as wind-driven coastal upwelling and the presence of a mesoscale cyclone to the north of Crete. In order to assess the impact of the FerryBox SST data in constraining the Aegean Sea hydrodynamic model which is part of the POSEIDON forecasting system, the in situ data were assimilated using an advanced multivariate assimilation scheme based on the Singular Evolutive Extended Kalman (SEEK) filter, a simplified square-root extended Kalman filter that operates with low-rank error covariance matrices as a way to reduce the computational burden. Thus during the period mid-August 2012-mid January 2013 in addition to the standard assimilating parameters, daily SST data along the ferryboat route from Piraeus to Heraklion were assimilated into the model. Inter-comparisons between the control run of the system (model run that uses only the standard data set of observations) and the experiment where the observational data set is augmented with the FerryBox SST data produce interesting results. Apart from the improvement of the SST error, the additional assimilation of daily of FerryBox SST

  4. Upper Cenozoic organic-rich sequences (offshore and onshore the south Aegean sea)

    SciTech Connect

    Anastasakis, G.

    1988-08-01

    The upper Cenozoic sedimentary column of the south Aegean Sea is composed mostly of marine sediments which have been deposited after the Seravallian breakup of the south Aegean landmass. Extensive submarine coring has revealed the frequent occurrence of Quaternary dark, organic-rich layers in the cores retrieved from water depths greater than 180 m. Moreover, deep-sea drilling (DSDP leg 42A) in the south Aegean basin recovered organic-rich layers as old as late Miocene. Onshore the south Aegean Sea islands, organic-rich sediments are found at the north and south territories of the region, on Milos and Crete islands. Especially on the island of Crete and south of it, on the smaller islands of Gavdos and Koufonisi, these organic-rich sediments represent a considerable portion of the widespread upper Cenozoic sediments. Stratigraphically they cover the interval between upper Seravallian and lower Pleistocene. The organic carbon content of all these mostly calcareous lithofacies, the so-called sapropels, ranges mostly between 0.5 and 6.5%. The most reliably chronostratigraphically correlated upper Pleistocene sapropels display similar compositional characteristics across the entire basin. Certain Pleistocene and older organic-rich layers contain increased proportions of siliceous tests. However the entire range of sapropels in the region (except those within the Messinian evaporites) can be described adequately by the same lithofacies association. To demonstrate this the authors compare the lower Tortonian Faneromeni Formation on Crete with the upper Quaternary sediments from the south Aegean Sea.

  5. Source mechanism of the 2014 Aegean Sea earthquake

    NASA Astrophysics Data System (ADS)

    Nakano, Masaru

    2016-04-01

    Rapid determination of centroid moment tensor (CMT) of earthquakes, namely the source centroid location, focal mechanism, and magnitude is important for early disaster responses and issuing Tsunami warnings. In order to evaluate capability of Turkey seismic network for rapid determinations of CMT, I investigate the source mechanism of the 2014 Aegean Sea earthquake (Mw 6.9). Although this event occur out of Turkey seismic network, I obtained stable CMT solution. The CMT solution of this earthquake represents a strike-slip fault, consistent with the geometry of the North Anatolian Fault (NAF), and the source-time function indicates that this event comprised several distinct subevents. Each subevent is considered to have ruptured a different fault segment. This observation indicates the existence of a mechanical barrier, namely a NAF segment boundary, at the hypocenter. I also determined CMT solutions of background seismicity. CMT solutions of background seismicity beneath the Aegean Sea represent strike-slip or normal faulting along the NAF or its branch faults. The tensional axes of these events are oriented northeast-southwest, indicating a transtensional tectonic regime. Beneath the Sea of Marmara, the CMT solutions represent mostly strike-slip faulting, consistent with the motion of the NAF, but we identified a normal fault event with a tensional axis parallel to the strike of the NAF. This mechanism indicates that a pull-apart basin, marking a segment boundary of the NAF, is developing there. Because ruptures of a fault system and large earthquake magnitudes are strongly controlled by the fault system geometry and fault length, mapping fault segments along NAF can help to improve the accuracy of scenarios developed for future disastrous earthquakes in the Marmara region.

  6. Teleconnections, Midlatitude Cyclones and Aegean Sea Turbulent Heat Flux Variability on Daily Through Decadal Time Scales

    NASA Technical Reports Server (NTRS)

    Romanski, Joy; Romanou, Anastasia; Bauer, Michael; Tselioudis, George

    2013-01-01

    We analyze daily wintertime cyclone variability in the central and eastern Mediterranean during 1958-2001, and identify four distinct cyclone states, corresponding to the presence or absence of cyclones in each basin. Each cyclone state is associated with wind flows that induce characteristic patterns of cooling via turbulent (sensible and latent) heat fluxes in the eastern Mediterranean basin and Aegean Sea. The relative frequency of occurrence of each state determines the heat loss from the Aegean Sea during that winter, with largest heat losses occurring when there is a storm in the eastern but not central Mediterranean (eNOTc), and the smallest occurring when there is a storm in the central but not eastern Mediterranean (cNOTe). Time series of daily cyclone states for each winter allow us to infer Aegean Sea cooling for winters prior to 1985, the earliest year for which we have daily heat flux observations. We show that cyclone states conducive to Aegean Sea convection occurred in 1991/1992 and 1992/1993, the winters during which deep water formation was observed in the Aegean Sea, and also during the mid-1970s and the winters of 1963/1964 and 1968/1969. We find that the eNOTc cyclone state is anticorrelated with the North Atlantic Oscillation (NAO) prior to 1977/1978. After 1977/1978, the cNOTe state is anticorrelated with both the NAO and the North Caspian Pattern (NCP), showing that the area of influence of large scale atmospheric teleconnections on regional cyclone activity shifted from the eastern to the central Mediterranean during the late 1970s. A trend toward more frequent occurrence of the positive phase of the NAO produced less frequent cNOTe states since the late 1970s, increasing the number of days with strong cooling of the Aegean Sea surface waters.

  7. Tsunami Propagation Database for the Mediterranean and Aegean Seas

    NASA Astrophysics Data System (ADS)

    Kanoglu, U.; Hoto, O.; Kalligeris, N.; Flouri, E.; Aydin, B.; Moore, C. W.; Synolakis, C. E.

    2012-12-01

    Pre-computed tsunami scenario databases are common tools to develop long- or short-term forecasting methodologies and hazard assessment approaches for tsunami-prone regions worldwide. The benefits of such databases include the possibility of probabilistic studies (Gonzalez et al., 2009, J. Geophys. Res. 114, Article Number: C11023), inundation mapping (Barberopoulou et al., 2011, Pure Appl. Geophys. 168(11), 2133-2146), or real-time forecasting (Wei et al., 2008, Geophys. Res. Lett. 35(4), Article Number: L04609). As a result, several tsunami propagation databases have been developed including one by NOAA's Pacific Marine Environmental Laboratory (PMEL), and another by the Australian Bureau of Meteorology (BOM). Pre-computed tsunami scenario databases utilize different approaches. PMEL's tsunami propagation database is based on the concept of a pre-computed tsunami scenarios consisting of propagation results from 100km x 50km fault planes with a slip value of 1m referred to as tsunami source functions. PMEL's source functions are placed along the subduction zones in several rows, covering known faults throughout the major ocean basins. Linearity of the tsunami propagation in the open ocean allows scaling and/or combination of the pre-computed tsunami source functions to generate a desired scenario. The BOM database considers five earthquakes with magnitudes changing from 7.0 to 9.0 at each location with 100km intervals along the subduction zone. However, to date, no similar approach has been computed along the subduction zones in the Aegean and Mediterranean Seas, even though, historically, there have been a considerable number of tsunami events which caused damage in the region (Ambraseys and Synolakis, 2010, J. Earthquake Eng. 14 (3), 309-330, Article Number: PII 919600673). A new project was initiated between Greece and Turkey supported by General Secretariat for Research & Technology, The Ministry for Development (GSRT) of Greece and The Scientific and

  8. Mixed Layer Depth in the Aegean, Marmara, Black and Azov Seas: Part II: Relation to the Sonic Layer Depth

    DTIC Science & Technology

    2009-03-03

    r.com/ locate / jmarsysMixed layer depth in the Aegean, Marmara, Black and Azov Seas : Part II: Relation to the sonic layer depth Robert W. Helber a...index terms: The Aegean Sea The Black Sea The Azov Sea Keywords: Sound transmission Mixed layer depth Climatologyt analysis of the seasonal evolution of...the sonic layer depth (SLD) relative to the mixed layer depth (MLD) for the Aegean, Marmara, Black, and Azov Seas . SLD identifies the acoustic ducting

  9. A new contribution to the Late Quaternary tephrostratigraphy of the Mediterranean: Aegean Sea core LC21

    NASA Astrophysics Data System (ADS)

    Satow, C.; Tomlinson, E. L.; Grant, K. M.; Albert, P. G.; Smith, V. C.; Manning, C. J.; Ottolini, L.; Wulf, S.; Rohling, E. J.; Lowe, J. J.; Blockley, S. P. E.; Menzies, M. A.

    2015-06-01

    Tephra layers preserved in marine sediments can contribute to the reconstruction of volcanic histories and potentially act as stratigraphic isochrons to link together environmental records. Recent developments in the detection of volcanic ash (tephra) at levels where none is macroscopically visible (so-called 'crypto-tephra') have greatly enhanced the potential of tephrostratigraphy for synchronising environmental and archaeological records by expanding the areas over which tephras are found. In this paper, crypto-tephra extraction techniques allow the recovery of 8 non-visible tephra layers to add to the 9 visible layers in a marine sediment core (LC21) from the SE Aegean Sea to form the longest, single core record of volcanic activity in the Aegean Sea. Using a novel, shard-specific methodology, sources of the tephra shards are identified on the basis of their major and trace element single-shard geochemistry, by comparison with geochemical data from proximal Mediterranean volcanic stratigraphies. The results indicate that the tephra layers are derived from 14 or 15 separate eruptions in the last ca 161 ka BP: 9 from Santorini; 2 or 3 from Kos, Yali, or Nisyros; 2 from the Campanian province; and one from Pantelleria. The attributions of these tephra layers indicate that 1) inter-Plinian eruptions from Santorini may have produced regionally significant tephra deposits, 2) marine tephrostratigraphies can provide unique and invaluable data to eruptive histories for island volcanoes, and 3) tephra from both Pantelleria and Campania may be used to correlate marine records from the Aegean Sea to those from the Tyrrhenian, Adriatic and Ionian Seas.

  10. Evolution of freshwater crab diversity in the Aegean region (Crustacea: Brachyura: Potamidae).

    PubMed

    Jesse, Ruth; Grudinski, Melanie; Klaus, Sebastian; Streit, Bruno; Pfenninger, Markus

    2011-04-01

    The aim of this study was to estimate the influence of the palaeogeographic and climatic history of the Aegean region on the diversity of freshwater crabs of the genus Potamon and to test whether this area served as source or reservoir in species diversity. Necessary species delimitation was accomplished by phylogenetic analyses of the mitochondrial markers COX1 and ND1, partial 16S rRNA gene and the tRNALeu gene. We found 14 genetic lineages of which nine could be assigned to previously recognised species. Temporal estimates of the splitting pattern in the phylogeny of Potamon indicated that a combination of geological and climatic events influenced their diversification. Within Potamon, the lineages separated into a western group and an eastern group. This first split in the genus occurred approximately 8.3-5.5 Mya, thus possibly correlated with the Messinian salinity crisis. A likelihood approach to geographic range evolution suggested for most species, occurring in the Aegean area, an origin in the Middle East. Moreover, there were no insular endemics in the central Aegean archipelago, therefore low sea-levels during the Pleistocene glacial periods possibly enabled dispersal to these islands, but subsequent rise in sea-level did not cause speciation. Nevertheless, the diversification of most lineages occurred during the Pleistocene epoch thus coinciding with Quaternary fluctuations of the climate.

  11. Trichoptera biodiversity of the Aegean and Adriatic sea basins in the republic of Kosovo.

    PubMed

    Ibrahimi, Halil; Kučinić, Mladen; Gashi, Agim; Grapci-Kotori, Linda

    2014-01-01

    We present the first preliminary inventory of Trichoptera taxa in the Aegean and Adriatic Sea basins in Kosovo that have previously received poor and fragmentary attention. Adult caddisflies were collected using ultraviolet (UV) light traps in 13 stations in areas of the Aegean Sea and Adriatic Sea drainage basins in Kosovo. Nineteen species out of 82, reported in this article, are first records for the Kosovo caddisfly fauna. Five genera are recorded for the first time in Kosovo: Brachycentrus, Ecclisopteryx, Psilopteryx, Thremma, and Oecetis. During this investigation, we found several Southeastern European endemic and rare species whose previous known distribution was limited to particular areas of this region, as well as other species whose distribution is considerably enlarged by this investigation: Polycentropus ierapetra, Polycentropus irroratus, Chaetopteryx stankovici, Drusus schmidi, Drusus tenellus, Potamophylax goulandriourum, Oecetis notata, and Notidobia melanoptera. Even though this article is a result of a limited sampling effort, it increases the number of Trichoptera taxa recorded for the Republic of Kosovo to 131.

  12. Static Stress Changes Inverted from Microseismicity in Eastern Aegean Sea

    NASA Astrophysics Data System (ADS)

    Leptokaropoulos, Konstantinos; Papadimitriou, Eleftheria; Orlecka-Sikora, Beata; Karakostas, Vassilios

    2014-05-01

    In this study we attempted to derive static stress field variations from the changes of earthquake production rates in Kusadasi bay and Samos island (eastern Aegean), by applying the Dieterich et al. (2000) Rate/State formulation. The calculation of stress changes from earthquake occurrence rates fluctuations should be obtained from catalogues which achieve adequate spatial and temporal resolution and well determined hypocenter coordinates. For this reason we took advantage of the data from a regional network operating since July of 2007, providing continuous monitoring of microseismicity, along with data available from seismological stations of the permanent Hellenic Unified Seismological Network (HUSN). The high accuracy and large sized regional catalogue is utilized for inverting seismicity rate changes into stress variation through a Rate/State dependent friction model. After explicitly determining the physical parameters incorporating in the modeling (reference seismicity rates, characteristic relaxation time, constitutive properties of fault zones) we investigated stress changes in both space and time regime and their possible connection with earthquake clustering and fault interactions. The main interest is focused on the June 2009 Samos Mw=5.1 event, which was followed by an intense seismic activity for several days. We attempt to reproduce and interpret stress changes both before and after the initiation of this seismic burst. The differences between the earthquake occurrence rates before and after the main shock are used as input data in a stress inversion algorithm based upon the Rate/State dependent friction concept in order to provide an estimation of stress changes. Diverse assumptions and combinations of the parameters values are tested for the model performance and sensitivity to be evaluated. The approach followed here could provide evidence of the robustness of the seismicity rate changes usage as a stress meter for both positive and negative

  13. The Etesian wind system and wind energy potential over the Aegean Sea

    NASA Astrophysics Data System (ADS)

    Dafka, Stella; Xoplaki, Elena; Garcia-Bustamante, Elena; Toreti, Andrea; Zanis, Prodromos; Luterbacher, Juerg

    2013-04-01

    The Mediterranean region lies in an area of great climatic interest since it is influenced by some of the most relevant mechanisms of the global climate system. In the frame of the three Europe 2020 priorities for a smart, sustainable and inclusive economy delivering high levels of employment, productivity and social cohesion, the Mediterranean energy plan is of paramount importance at the European level, being an area with a significant potential for renewable energy from natural sources that could play an important role in responding to climate change effects over the region. We present preliminary results on a study of the Etesian winds in the past, present and future time. We investigate the variability and predictability of the wind field over the Aegean. Statistical downscaling based on several methodologies will be applied (e.g. canonical correlation analysis and multiple linear regression). Instrumental time series, Era-Interim and the 20CR reanalyses will be used. Large-scale climate drivers as well as the influence of local/regional factors and their interaction with the Etesian wind field will be addressed. Finally, the Etesian wind resources on the present and future climate will be assessed in order to identify the potential areas suitable for the establishment of wind farms and the production of wind power in the Aegean Sea.

  14. 8 January 2013 Mw=5.7 North Aegean Sea Earthquake Sequence

    NASA Astrophysics Data System (ADS)

    Kürçer, Akın; Yalçın, Hilal; Gülen, Levent; Kalafat, Doǧan

    2014-05-01

    The deformation of the North Aegean Sea is mainly controlled by the westernmost segments of North Anatolian Fault Zone (NAFZ). On January 8, 2013, a moderate earthquake (Mw= 5.7) occurred in the North Aegean Sea, which may be considered to be a part of westernmost splay of the NAFZ. A series of aftershocks were occurred within four months following the mainschock, which have magnitudes varying from 1.9 to 5.0. In this study, a total of 23 earthquake moment tensor solutions that belong to the 2013 earthquake sequence have been obtained by using KOERI and AFAD seismic data. The most widely used Gephart & Forsyth (1984) and Michael (1987) methods have been used to carry out stress tensor inversions. Based on the earthquake moment tensor solutions, distribution of epicenters and seismotectonic setting, the source of this earthquake sequence is a N75°E trending pure dextral strike-slip fault. The temporal and spatial distribution of earthquakes indicate that the rupture unilaterally propagated from SW to NE. The length of the fault has been calculated as approximately 12 km. using the afterschock distribution and empirical equations, suggested by Wells and Coppersmith (1994). The stress tensor analysis indicate that the dominant faulting type in the region is strike-slip and the direction of the regional compressive stress is WNW-ESE. The 1968 Aghios earthquake (Ms=7.3; Ambraseys and Jackson, 1998) and 2013 North Aegean Sea earthquake sequences clearly show that the regional stress has been transferred from SW to NE in this region. The last historical earthquake, the Bozcaada earthquake (M=7.05) had been occurred in the northeast of the 2013 earthquake sequence in 1672. The elapsed time (342 year) and regional stress transfer point out that the 1672 earthquake segment is probably a seismic gap. According to the empirical equations, the surface rupture length of the 1672 Earthquake segment was about 47 km, with a maximum displacement of 170 cm and average displacement

  15. Mixed Layer Depth in the Aegean, Marmara, Black and Azov Seas: Part I: General Features

    DTIC Science & Technology

    2009-02-28

    r.com/ locate / jmarsysMixed layer depth in the Aegean, Marmara, Black and Azov Seas : Part I: General features A. Birol Kara a,⁎, Robert W. Helber a...suffer from lack of input T and S profiles in the Marmara and Azov Seas , thus they may not be representative.MonthlyMLDfields presented in this paper are...Boyer), .V.there has been no study which describes seasonal characteristics of MLD in the Aegean, Marmara, Black and Azov Seas , whose bottom

  16. Progress of KOERI Tsunami Warning System for the Eastern Mediterranean, Aegean and Black Seas

    NASA Astrophysics Data System (ADS)

    Necmioglu, Ocal; Meral Ozel, Nurcan; Ozer Sozdinler, Ceren; Yilmazer, Mehmet; Cokacar, Tulay; Comoglu, Mustafa; Pinar, Ali; Kekovali, Kivanc

    2016-04-01

    This presentation provides a progress report on the activities of the Bogazici University / Kandilli Observatory and Earthquake Research Institute - Regional Earthquake and Tsunami Monitoring Center (KOERI-RETMC) which provides services as a Candidate Tsunami Service Provider (CTSP) of ICG/NEAMTWS in the Eastern Mediterranean, Aegean and Black Seas since 1 July 2012. KOERI continues to operate 178 BB and 97 strong motion and 6 short period sensors and the regional coverage includes 77 stations from GFZ and additional 16 stations through bilateral agreements. One radar-type tide-gauge has been installed in Fethiye within the framework of "Inexpensive Device for Sea-Level Measurement" (IDSL) initiative offered as donation by the EC/JRC and planning is in progress for the possible installation of three more IDSLs in selected locations in the Aegean Sea coast of Turkey. The capabilities and the limitations of HF Radar technology for the purpose of tsunami detection in the Eastern Mediterranean has been identified and the maturity and the applicability of these systems for the possible use under the Tsunami Warning System has been determined. The development of the TsuComp as a user-friendly interface to be used in the assessment of tsunamigenic potential and as a single-point entry for message dissemination has been finalized. The work towards the creation of Tsunami Inundation Maps at the Tsunami Forecast Points in Turkey is near finalization. This work is partially funded by project ASTARTE - Assessment, Strategy And Risk Reduction for Tsunamis in Europe - FP7-ENV2013 6.4-3, Grant 603839. The authors would like to thank EC/JRC and Mr. Alessandro Annunziato for their continuous support in the operational activities of RETMC and IDSL initiative.

  17. Shallow structure and recent evolution of the Aegean Sea deduced from the seismic reflection analysis

    SciTech Connect

    Laure, M.; Mascle, J.

    1988-08-01

    Together with the Tyrrhenian Sea, the Aegean Sea represents one of two marine basins still developing as a consequence of the subduction of the African lithosphere beneath Europe. Despite many geophysical similarities with the Tyrrhenian Sea, the Aegean displays a specific structural segmentation characterized by two distinct domains separated by the central Aegean. To the north of the basin, the so-called North Aegean trough likely represents the western marine extension of the transtensive Anatolian transform fault zone. The northern margin of this area contains a series of disconnected, often thickly sedimented small basins that probably initiated during the late Miocene as a consequence of a dominantly north-south extension; typical uppermost Miocene (Messinian) formations can be observed on seismic grounds. To the south, the Cretan Sea shows clear evidence of important distensive events occurring during two main episodes and following two main trends; a dominantly north-south-directed extension is responsibile for most of the structural features detected along both the Cretan and southern Cyclades margins.

  18. Phytoplankton size-based dynamics in the Aegean Sea (Eastern Mediterranean)

    NASA Astrophysics Data System (ADS)

    Ignatiades, L.; Psarra, S.; Zervakis, V.; Pagou, K.; Souvermezoglou, E.; Assimakopoulou, G.; Gotsis-Skretas, O.

    2002-07-01

    This study represents one component of the large MTP-II-MATER (MAST-III) multidisiplinary project in the Mediterranean supported by EU. Data were collected during three cruises performed in Spring and Autumn 1997 and Spring 1998 from six stations of the North and five stations of the South Aegean Sea. The work assessed the spatial, vertical and temporal variations of size fractionated chlorophyll α, primary production (in situ), photosynthetic parameters (in situ) and the taxonomic composition of phytoplankton. The population structure and dynamics were greatly influenced by the different hydrographic conditions prevailing in the Northern and Southern Aegean Sea due to the influence of Black Sea and Levantine Sea waters, respectively. The picoplankton fraction (0.2-1.2 μm) predominated and accounted for the 56% to 49% of total chl α and the 51% to 41% of total primary production in the N. and S. Aegean Sea, respectively. Throughout the sampling area, the levels of nano+microplankton (>3.0 μm) were next in abundance proportions of total chl α (21-31%) and primary production (20-33%) and the levels of the ultraplankton (1.2-3.0 μm) were the lowest, contributing the 18-22% of total chl α and the 20-23% of total primary production. There was a highly significant ( P≤0.005-0.01) spatial, vertical and temporal influence on the biomass and productivity of all size classes in the N. Aegean and of most of them in S. Aegean. Light utilization efficiency ( ɛ%) and quantum yield ( ϕmax) exhibited a temporal trend having higher values in Spring than in Autumn as well as a trend affected by cell size, being higher for picoplankton in relation to ultraplankton and nano+microplankton. Assimilation ratios ( PB) increased with cell size. Daily primary production in the N. Aegean (81.36 mg C m -2 day -1) was higher than that in the S. Aegean (38.88 mg C m -2 day -1) but both are characterized as the most oligotrophic areas of the eastern Mediterranean.

  19. Analysis and Modeling Using Multi-Year Satellite Observations in the Aegean and Eastern Mediterranean Seas

    DTIC Science & Technology

    2006-12-01

    a network of buoys in in the Mediterranean Sea, as observed by the TOPEX/Posei R9 Aegean Sea, maintained by the Hellenic Centre for radar altimeter...Ocean Associates, 2004], including an imaging found in the circulation of the Western Mediterranean radar on the Space Shuttle. Two sources of data...numerical simu- high-resolution visible images and synthetic aperture lation of circulation by Pinardi et al. [1997] showed radar (SAR) images. that

  20. Structure of flows in the Northern Aegean Sea from a pilot drifter array

    NASA Astrophysics Data System (ADS)

    Kourafalou, V.; Olson, D.; Johns, W.; Kontoyiannis, H.; Zervakis, V.

    2003-04-01

    An array of thirty drifters deployed in the northern Aegean are used to consider the circulation in a complex archipelago of islands. The circulation of the Aegean is largely influenced by a combination of buoyancy from freshwaters introduced from the Black Sea via the Dardenelles Straits and from coastal rivers and by wind forcing. The latter is highly structured as the winds along the axis of the Aegean Sea are channeled between the orography of the Greek peninsula and islands. The above mechanisms are revealed in the drifter tracts. Preferred pathways that mark transport and exchange between the northern and southern parts of the basin are also evident. The drifters equipped with hourly GPS location and holly sock drogues provide information of time and space scales that have not been routinely sampled before. After a brief review of the overall circulation outlined by the array, the statistics of the turbulent field and its variation for the various subbasins are described. Of special interest are coastal plumes, motions induced as fluid passes between sub-basins, and the nature of cyclonic flows trapped within deep topographic pockets through the Aegean. An initial comparison of eddy statistics in relationship to wind events is also reported.

  1. Diagnostics of Cyclogenesis Over the Aegean Sea Using Potential Vorticity Inversion

    NASA Astrophysics Data System (ADS)

    Flocas, H. A.

    In this study an attempt is made to investigate comprehensively the dynamics of a case of cyclogenesis over the Aegean Sea within the context of the potential vorticity. At early stages the cyclogenesis is manifested by a large scale development at the upper levels over Adriatic Sea and Yugoslavia associated with an upper tropospheric potential vorticity anomaly. At later stages a smaller scale development was generated over Aegean Sea associated with a low-level potential vorticity anomaly and a surface warm anomaly. By means of a two-dimensional potential vorticity inversion it is demonstrated that the scale, the position and the strength of the involved anomalies contribute to the surface development, however, the low-level potential vorticity anomaly seems to constitute the most significant feature, more likely to be associated with condensation.

  2. Temporal and spatial variations in provenance of Eastern Mediterranean Sea sediments: Implications for Aegean and Aeolian arc volcanism

    NASA Astrophysics Data System (ADS)

    Klaver, Martijn; Djuly, Thomas; de Graaf, Stefan; Sakes, Alex; Wijbrans, Jan; Davies, Gareth; Vroon, Pieter

    2015-03-01

    The Eastern Mediterranean Sea (EMS) is the last remnant of the Tethys Ocean that has been subducted to the north since the Jurassic. Subduction has led to the formation of multiple island arcs in the EMS region where the Aeolian and Aegean arcs are currently active. The EMS is surrounded by continents and receives a large sediment input, part of which is transported down with the subducting slab into the mantle and potentially contributes a major flux to the arc volcanism. An along-arc gradient in the composition of subducting sediment has been evoked to explain the distinct geochemical signature of the easternmost volcanic centre of the Aegean arc, but direct evidence for this proposal is lacking. We present a detailed study of the mineralogical, major-, trace elements and Sr-Nd-Hf-Pb isotope composition of 45 Neogene EMS sediment samples obtained from Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP) drill sites and box cores to characterise their geochemical composition, distinguish provenance components and investigate the temporal and spatial variation in provenance to evaluate the potential changing contribution of subducted EMS sediment to Aegean and Aeolian arc volcanism. Based on trace element characteristics of EMS sediments, we can distinguish four provenance components. Nile sediment and Sahara dust are the main components, but contributions from the Tethyan ophiolite belt and arc volcanic rocks in the north are also recognised. Pliocene and Quaternary EMS sediment records a strong geochemical gradient where Nile River sediment entering the EMS in the east is progressively diluted by Sahara Desert dust towards the west. Pre-Messinian samples, however, have a remarkably homogeneous composition with Nile sediment characteristics. We relate this rapid increase in Sahara dust contribution to a late Miocene climate shift leading to decreased Nile runoff and aridification of the Sahara region. EMS sediment has a restricted range in Pb isotopes

  3. Large-scale bioprospecting of cyanobacteria, micro- and macroalgae from the Aegean Sea.

    PubMed

    Montalvão, Sofia; Demirel, Zeliha; Devi, Prabha; Lombardi, Valter; Hongisto, Vesa; Perälä, Merja; Hattara, Johannes; Imamoglu, Esra; Tilvi, Supriya Shet; Turan, Gamze; Dalay, Meltem Conk; Tammela, Päivi

    2016-05-25

    Marine organisms constitute approximately one-half of the total global biodiversity, being rich reservoirs of structurally diverse biofunctional components. The potential of cyanobacteria, micro- and macroalgae as sources of antimicrobial, antitumoral, anti-inflammatory, and anticoagulant compounds has been reported extensively. Nonetheless, biological activities of marine fauna and flora of the Aegean Sea have remained poorly studied when in comparison to other areas of the Mediterranean Sea. In this study, we screened the antimicrobial, antifouling, anti-inflammatory and anticancer potential of in total 98 specimens collected from the Aegean Sea. Ethanol extract of diatom Amphora cf capitellata showed the most promising antimicrobial results against Candida albicans while the extract of diatom Nitzschia communis showed effective results against Gram-positive bacterium, S. aureus. Extracts from the red alga Laurencia papillosa and from three Cystoseira species exhibited selective antiproliferative activity against cancer cell lines and an extract from the brown alga Dilophus fasciola showed the highest anti-inflammatory activity as measured in primary microglial and astrocyte cell cultures as well as by the reduction of proinflammatory cytokines. In summary, our study demonstrates that the Aegean Sea is a rich source of species that possess interesting potential for developing industrial applications.

  4. Peracarida populations of hard substrate assemblages in ports of the NW Aegean Sea (eastern Mediterranean)

    NASA Astrophysics Data System (ADS)

    Chintiroglou, C.-C.; Antoniadou, C.; Baxevanis, A.; Damianidis, P.; Karalis, P.; Vafidis, D.

    2004-02-01

    This study deals with the structure of Peracarida populations in four ports in the NW Aegean Sea, Greece, and with the degree this structure is influenced by the particular biotic and abiotic conditions that prevail in the ports. Quantitative samples were taken during summer and winter in two successive years from artificial hard substrates and were analysed using common biocoenotic methods. The examination of approximately 81,250 specimens revealed the presence of 24 Peracarida species, the most dominant of which were Corophium acutum, Leptochelia savignyi and Elasmopus rapax. All species are very common and have been reported from many sites and assemblages in the N Aegean Sea. The ratios of certain Peracarida genera are discussed as possible indicators of environmental health that may be used in long-term biomonitoring programmes on the impact of pollution in harbours.

  5. Mesozooplankton stable isotope composition in Cyprus coastal waters and comparison with the Aegean Sea (eastern Mediterranean)

    NASA Astrophysics Data System (ADS)

    Hannides, Cecelia C. S.; Zervoudaki, Soultana; Frangoulis, Constantin; Lange, Manfred A.

    2015-03-01

    Here we use bulk and amino acid-specific stable nitrogen (N) isotope analysis (AA-CSIA) to evaluate seasonal and regional change in mesozooplankton dynamics for the first time in coastal waters of the eastern Mediterranean. Cyprus mesozooplankton δ15N values were significantly higher in late winter (2.3‰) than in summer (1.2‰), and in all cases were less than the δ15N values of mesozooplankton in the northeast Aegean Sea (NEA; 3.4‰). AA-CSIA indicates that these differences can primarily be attributed to seasonal and regional change in mesozooplankton community trophic structure, with overall trophic position increasing by 0.2-0.3 in winter as compared to summer around Cyprus, and trophic position higher in the NEA than in Cyprus by 0.3-0.6. Such differences are most likely related to the larger contribution of carnivorous mesozooplankton observed in winter around Cyprus and in the NEA. Overall, our findings indicate change in bulk mesozooplankton δ15N value in the eastern Mediterranean is primarily driven by change in community trophic position, rather than variability in δ15N value at the base of the food web.

  6. Bacterial pollution, activity and heterotrophic diversity of the northern part of the Aegean Sea, Turkey.

    PubMed

    Çiftçi Türetken, Pelin S; Altuğ, Gülşen

    2016-02-01

    Isolation and characterization studies of marine heterotrophic bacteria are important to describe and understand eco-metobolism of the marine environments. In this study, diversity and community structures of the culturable heterotrophic bacteria, metabollicaly active bacteria and bacterial pollution in the coastal and offshore areas of Gökçeada Island, in the Northern Aegean Sea, Turkey were investigated from March 2012 to November 2013. The primary hydrographic parameters were recorded in situ. The frequency of the metabolically active bacteria was determined by using a modified staining technique. The indicator bacteria were determined by using membrane filtration technique; 126 bacteria isolates, 24 of them first records for this region, were identified using an automated micro-identification system, VITEK2 Compact30. The results showed that detected bacterial community profiles were significantly different when compared with previous studies conducted in polluted marine areas of Turkey. High frequency of faecal bacteria detected at station 2 indicated that increasing human activities and terrestrial pollution sources are shaping factors for possible risks, regarding recreational uses of this region, in the summer seasons.

  7. Climate change effects on the marine characteristics of the Aegean and Ionian Seas

    NASA Astrophysics Data System (ADS)

    Makris, Christos; Galiatsatou, Panagiota; Tolika, Konstantia; Anagnostopoulou, Christina; Kombiadou, Katerina; Prinos, Panayotis; Velikou, Kondylia; Kapelonis, Zacharias; Tragou, Elina; Androulidakis, Yannis; Athanassoulis, Gerasimos; Vagenas, Christos; Tegoulias, Ioannis; Baltikas, Vassilis; Krestenitis, Yannis; Gerostathis, Theodoros; Belibassakis, Kostantinos; Rusu, Eugen

    2016-12-01

    This paper addresses the effects of estimated climate change on the sea-surface dynamics of the Aegean and Ionian Seas (AIS). The main aim is the identification of climate change impacts on the severity and frequency of extreme storm surges and waves in areas of the AIS prone to flooding. An attempt is made to define design levels for future research on coastal protection in Greece. Extreme value analysis is implemented through a nonstationary generalized extreme value distribution function, incorporating time harmonics in its parameters, by means of statistically defined criteria. A 50-year time span analysis is adopted and changes of means and extremes are determined. A Regional Climate Model (RegCM3) is implemented with dynamical downscaling, forced by ECHAM5 fields under 20C3M historical data for the twentieth century and the SRES-A1B scenario for the twenty-first century. Storm surge and wave models (GreCSSM and SWAN, respectively) are used for marine climate simulations. Comparisons of model results with reanalysis and field data of atmospheric and hydrodynamic characteristics, respectively, are in good agreement. Our findings indicate that the dynamically downscaled RegCM3 simulation adequately reproduces the present general circulation patterns over the Mediterranean and Greece. Future changes in sea level pressure and mean wind fields are estimated to be small, yet significant for marine extremes. In general, we estimate a projected intensification of severe wave and storm surge events during the first half of the twenty-first century and a subsequent storminess attenuation leading to the resettlement of milder extreme marine events with increased prediction uncertainty in the second half of the twenty-first century.

  8. Assessment of organotin (butyltin species) contamination in marine biota from the Eastern Aegean Sea, Turkey.

    PubMed

    Kucuksezgin, F; Aydin-Onen, S; Gonul, L T; Pazi, I; Kocak, F

    2011-09-01

    The marine environment continues to be adversely affected by tributyltin (TBT) release from maritime traffic. Therefore the concentrations of TBT, dibutyltin (DBT) and monobutyltin (MBT) were measured in barnacles, mussels and fish along the Eastern Aegean coastline. The average concentrations of TBT ng Sn g⁻¹ were found to be 235 in fish, 116 in mussels and 635 in barnacles. The highest concentrations of TBT, DBT and MBT were observed in the barnacles which had been sampled in marinas and harbors. All mussels sampled showed values of TBT+DBT, which were below the "tolerable average residue level (TARL)" as currently accepted. This indicates a lack of risk to the consumer. However, 7 out of the 15 fish sampled displayed TBT+DBT levels above the TARL, which indicates that a fish consumer group may be at risk. Barnacles have high potential as biomonitors for the presence of organotin in the Aegean Sea.

  9. Air and seawater pollution and air-sea gas exchange of persistent toxic substances in the Aegean Sea: spatial trends of PAHs, PCBs, OCPs and PBDEs.

    PubMed

    Lammel, Gerhard; Audy, Ondřej; Besis, Athanasios; Efstathiou, Christos; Eleftheriadis, Kostas; Kohoutek, Jiři; Kukučka, Petr; Mulder, Marie D; Přibylová, Petra; Prokeš, Roman; Rusina, Tatsiana P; Samara, Constantini; Sofuoglu, Aysun; Sofuoglu, Sait C; Taşdemir, Yücel; Vassilatou, Vassiliki; Voutsa, Dimitra; Vrana, Branislav

    2015-08-01

    Near-ground air (26 substances) and surface seawater (55 substances) concentrations of persistent toxic substances (PTS) were determined in July 2012 in a coordinated and coherent way around the Aegean Sea based on passive air (10 sites in 5 areas) and water (4 sites in 2 areas) sampling. The direction of air-sea exchange was determined for 18 PTS. Identical samplers were deployed at all sites and were analysed at one laboratory. hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs) as well as dichlorodiphenyltrichloroethane (DDT) and its degradation products are evenly distributed in the air of the whole region. Air concentrations of p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) and o,p'-DDT and seawater concentrations of p,p'-DDE and p,p'-DDD were elevated in Thermaikos Gulf, northwestern Aegean Sea. The polychlorinated biphenyl (PCB) congener pattern in air is identical throughout the region, while polybrominated diphenylether (PBDE)patterns are obviously dissimilar between Greece and Turkey. Various pollutants, polycyclic aromatic hydrocarbons (PAHs), PCBs, DDE, and penta- and hexachlorobenzene are found close to phase equilibrium or net-volatilisational (upward flux), similarly at a remote site (on Crete) and in the more polluted Thermaikos Gulf. The results suggest that effective passive air sampling volumes may not be representative across sites when PAHs significantly partitioning to the particulate phase are included.

  10. Reconstructing Holocene sea surface salinity changes in the Northern Aegean Sea: evidence from morphological variations of Emiliania huxleyi-coccoliths

    NASA Astrophysics Data System (ADS)

    Herrle, Jens O.; Gebühr, Christina; Bollmann, Jörg; Giesenberg, Annika; Kranzdorf, Philip

    2013-04-01

    The Aegean Sea is a key area for our understanding of the impact of changes in the hydrological cycle on ocean circulation in the Mediterranean Sea. The Aegean Sea appears to be very sensitive to climate changes in Europe because of its small volume and the position between high- and low-latitude climate regimes. Therefore, it is assumed to record environmental change, especially changes in sea surface water salinity (SSS) without a significant time lag with respect to the forcing process (Rohling et al., 2002). However, up to date, SSS cannot be easily reconstructed from geological archives because several assumptions need to be made that lead to a significant error of the salinity estimates (e.g. Rohling, 2000). Here, we present the first high resolution SSS reconstruction from a Holocene sediment core based on a recently developed transfer function using the morphological variation of Emiliania huxleyi coccoliths (Bollmann & Herrle 2007, Bollmann et al., 2009). The core is located in the northern Aegean Sea (eastern Mediterranean Basin) and covers the time period 3 -11ka ago. Sea surface water salinity in the Aegean Sea has varied in concert with temperature oscillations as recorded in Greenland ice cores (iGISP2 ice core δ18O record) with a periodicity of about 900 years (Schulz & Paull, 2002). Four major SSS events can be identified at about 3.9, 4.7, 6.4, 7.4, and 8.2 ka in the northern Aegean Sea that correlate with increases in GISP2 δ18O (Schulz & Paull, 2002) as well as decreasing percentages of tree pollen studied at the same core expect for 3.9 ka (Kotthoff et al., 2008). The most prominent salinity increase occurred during the short-lived 8.2 kyr cold event (e.g., Rohling & Pälike, 2005), which was most likely triggered by a melt-water related perturbation of the Atlantic Meridional Overturning and associated decrease of ocean heat transport to the North Atlantic. We suggest that the salinity fluctuations in the northern Aegean Sea are related to

  11. Exploration of the Black, Aegean, and Mediterranean Seas Aboard E/V Nautilus

    NASA Astrophysics Data System (ADS)

    Bell, K. L.; Ballard, R. D.; Brennan, M. L.; Raineault, N. A.; Shank, T. M.; Mayer, L. A.; Roman, C.; Mitchell, G. A.; Coleman, D. F.

    2012-12-01

    In the summer of 2012, the Exploration Vessel (E/V) Nautilus undertook a two-month expedition to the Black, Aegean, and Mediterranean Seas. The primary goal of the Nautilus is to create a focus of international leadership for the development and integration of leading-edge technologies, educational programs, field operations, and public outreach programs for ocean exploration, in partnership with the NOAA Office of Ocean Exploration, National Geographic Society, Office of Naval Research, and corporate partners. To do so, the program uses a complement of deep submergence vehicle systems and telepresence technologies to engage scientists, educators and the public, both at sea and ashore, allowing them to become integral members of the on-board exploration team. When discoveries are made, experts ashore are notified and brought aboard virtually within a short period of time to help guide shipboard response before the ship moves on. The 2012 expedition is comprised of four areas of interest. Extensive sidescan mapping took place off the Turkish coasts of the southern Black Sea and eastern Aegean Sea, and was followed by remotely operated vehicle (ROV) dives on targets of archaeological, geological, and biological interest. In the Black Sea, additional work was done on the porewater chemistry of the sediments in the oxic, suboxic, and anoxic zones. Nautilus returned to the Anaximander Seamounts, including Kazan, Amserdam, Thessaloniki, and Athina, to further explore active and formerly active seep sites located in 2010. Finally, based on biological and geological discoveries made on Eratosthenes Seamount in the eastern Mediterranean Sea, we returned to further study chemosynthetic vent communities and tectonic processes.;

  12. Particulate and dissolved primary production along a pronounced hydrographic and trophic gradient (Turkish Straits System-NE Aegean Sea)

    NASA Astrophysics Data System (ADS)

    Lagaria, A.; Psarra, S.; Gogou, A.; Tuğrul, S.; Christaki, U.

    2013-06-01

    The rates of particulate (PPp) and dissolved primary production (PPd) were estimated along a trajectory of variable environmental regimes formed in a narrow shelf area, following the course of Black Sea water masses (BSW) passing through the Turkish Straits System (TSS) into the NE Aegean Sea (BS-AS outflow). Seven stations in total were sampled, covering a transect from the eastern edge of the Marmara Sea basin to the NE Aegean Sea, during two consecutive cruises performed in October 2008 within the framework of the EU SESAME project. Along the BS-AS outflow, depth-integrated over the surface BSW layer PPp decreased considerably from 91 to < 16 mg C m- 2 h- 1 whereas PPd increased from 3 to 10 mg C m- 2 h- 1. As a consequence, the relative importance of PPd over total production (percentage extracellular release, PER) increased from 6% (± 3% sd) in the Marmara Sea to 37% (± 4% sd) in the NE Aegean Sea. Total chlorophyll a concentration gradually decreased and phytoplankton community size-structure was modified, with pico-phytoplankton, that originally represented 35% (± 9% sd) in the Marmara Sea, gradually becoming dominant in the NE Aegean (77% ± 2% sd), substituting large nano- and micro-phytoplankton cells (> 5 μm). This study showed that PER increased along a gradient from mesotrophy to oligotrophy, probably due to nutrient deficiency constraining phytoplankton growth and was closely related to phytoplankton size-structure. In the oligotrophic NE Aegean Sea, phytoplankton exudation was a significant source of dissolved organic carbon for heterotrophic prokaryotes.

  13. Observed TEC Anomalies by GNSS Sites Preceding the Aegean Sea Earthquake of 2014

    NASA Astrophysics Data System (ADS)

    Ulukavak, Mustafa; Yal&ccedul; ınkaya, Mualla

    2016-11-01

    In recent years, Total Electron Content (TEC) data, obtained from Global Navigation Satellites Systems (GNSS) receivers, has been widely used to detect seismo-ionospheric anomalies. In this study, Global Positioning System - Total Electron Content (GPS-TEC) data were used to investigate ionospheric abnormal behaviors prior to the 2014 Aegean Sea earthquake (40.305°N 25.453°E, 24 May 2014, 09:25:03 UT, Mw:6.9). The data obtained from three Continuously Operating Reference Stations in Turkey (CORS-TR) and two International GNSS Service (IGS) sites near the epicenter of the earthquake is used to detect ionospheric anomalies before the earthquake. Solar activity index (F10.7) and geomagnetic activity index (Dst), which are both related to space weather conditions, were used to analyze these pre-earthquake ionospheric anomalies. An examination of these indices indicated high solar activity between May 8 and 15, 2014. The first significant increase (positive anomalies) in Vertical Total Electron Content (VTEC) was detected on May 14, 2014 or 10 days before the earthquake. This positive anomaly can be attributed to the high solar activity. The indices do not imply high solar or geomagnetic activity after May 15, 2014. Abnormal ionospheric TEC changes (negative anomaly) were observed at all stations one day before the earthquake. These changes were lower than the lower bound by approximately 10-20 TEC unit (TECU), and may be considered as the ionospheric precursor of the 2014 Aegean Sea earthquake

  14. Operational monitoring and forecasting in the Aegean Sea: system limitations and forecasting skill evaluation.

    PubMed

    Nittis, K; Zervakis, V; Perivoliotis, L; Papadopoulos, A; Chronis, G

    2001-01-01

    The POSEIDON system, based on a network of 11 oceanographic buoys and a system of atmospheric/oceanic models, provides real-time observations and forecasts of the marine environmental conditions in the Aegean Sea. The buoy network collects meteorological, sea state and upper-ocean physical and biochemical data. The efficiency and functionality of the various system components are being evaluated during the present pre-operational phase and discussed in this paper. The problem of bio-fouling on optical and chemical sensors is found to be a main limitation factor on the quality of data. Possible solutions to this problem as well as quality control methods that are being developed are also described. Finally, an evaluation of the numerical models is presented through the estimation of their forecasting skill for selected periods.

  15. Biodiversity of zoobenthic hard-substrate sublittoral communities in the Eastern Mediterranean (North Aegean Sea)

    NASA Astrophysics Data System (ADS)

    Antoniadou, Chryssanthi; Chintiroglou, Chariton

    2005-03-01

    The spatial dispersion of zoobenthos from sublittoral hard substrate communities in the northern part of the Aegean Sea has been studied during summer 1997 and 1998. Material was collected by SCUBA diving, by totally scraping off five replicate quadrates (400 cm 2 each) at three depth levels (15, 30, 40 m) from six sites located in Chalkidiki peninsula, plus one in Kavala Gulf. The examination of the 19,343 living specimens collected revealed the presence of 314 species. Though the multivariate analyses showed high similarity between stations, the structure of this sciaphilic algal community seems to have an increased spatial heterogeneity. Four distinct facies were recorded in accordance with the occurrence of different algal forms, the degree of hard substrate inclination and the water clarity. A short review on the biodiversity of sublittoral communities in the Mediterranean revealed the affinity between the western and the eastern basin and also among the photophilic and the sciaphilic algal communities.

  16. Concentration of heavy metals in seawater and sediments from the northern Aegean Sea, Greece

    SciTech Connect

    Fytianos, K; Vasilikiotis, G.S.

    1983-01-01

    The aim of the study presented was to investigate the distribution of heavy metals in seawater and sediments in areas, which face increasing marine pollution problems, due to the industrialization and especially in the closed gulfs of Thermaikos and Kavala in north Aegean sea. The city of Thessaloniki with more than 1,200,000 inhabitants and the surrounding industrial area use Thermaikos Gulf as the final receiver for their liquid wastes. The Gulf of Thermaikos receives domestic, agricultural, industrial and natural runoff from a heavily populated and fairly industrialized area. The heavy metal contamination is mainly affected by industrial wastes from oil refinery, steel industry, a fertilizer plant and some other industries located in the industrial area, west of the city.

  17. Metal levels in sediments and transplanted mussels in Pagassitikos Gulf (Aegean Sea, Eastern Mediterranean).

    PubMed

    Tsangaris, Catherine; Kaberi, Helen; Catsiki, Vassiliki-Angelique

    2013-07-01

    Metal concentrations were determined in surface sediments and transplanted mussels in a shallow semi-enclosed bay, Pagassitikos Gulf, Aegean Sea. Cu, Zn, Pb, Hg, and As levels in sediments were enriched close to point sources of pollution, i.e., Volos Port and cement plant. Fe, Mn, Cr, and Ni spatial distributions in sediments were rather uniform with increasing concentrations towards deeper sites, suggesting natural enrichment, whereas levels found in the port, although elevated, were not the highest in the study area. Spatial variations in concentrations of most metals in mussels transplanted nearshore were generally in accordance to those in sediments, with the highest Fe, Mn, Cr, Ni, and Cu levels in the port and the highest Hg levels close to the cement plant. Concentrations of metals in sediments and transplanted mussels were comparable to those reported in Mediterranean areas. Results indicate that pollution point sources contribute to anthropogenic metal enrichment in the study area.

  18. Macrofauna biodiversity of mussel bed assemblages in Thermaikos Gulf (northern Aegean Sea)

    NASA Astrophysics Data System (ADS)

    Chintiroglou, Chariton-Charles; Damianidis, Panagiotis; Antoniadou, Chryssanthi; Lantzouni, Marina; Vafidis, Dimitris

    2004-02-01

    Biomonitoring of mussel bed assemblages can provide valuable information about the impact of pollution on hard substrate assemblages. This study of Mytilus galloprovincialis mussel beds in Thermaikos Gulf (northern Aegean Sea) deals with the spatial and temporal structure of the associated fauna. Samples were collected and abiotic factors were measured in two successive years. Common biocoenotic methods were employed to analyze the data. The samples could be separated into three groups, with summer and winter samples being clearly different. A total of 100 species were found: polychaetes and crustaceans were the most dominant taxa. The assemblage shows high diversity with respect to species abundance. Biotic interactions within the assemblage appear to influence its composition, although the total evenness remains unaffected in space and time. The M. galloprovincialis assemblages can be found in clean as well as in polluted waters and, therefore, are of great interest in biomonitoring studies.

  19. Styela plicata: a new promising bioindicator of heavy metal pollution for eastern Aegean Sea coastal waters.

    PubMed

    Aydın-Önen, S

    2016-11-01

    As part of a research project, the concentrations of Cd, Cu, Pb, V, and Zn in the tissues of Styela plicata were investigated for the first time to determine if S. plicata is a suitable biological indicator for biomonitoring of heavy metals in eastern Aegean Sea coastal waters. To examine the relationships, heavy metal levels in suspended particulate matters (SPMs) and sediments were also determined. According to the results, the mean metal levels in SPM, sediments, and S. plicata samples could be arranged in the following order of abundance: Zn > Cu > Pb > V > Cd. As for heavy metal levels, significant positive correlations were noted between Cd-Pb, Cd-V, Cd-Zn, Cu-V, and Pb-V in SPM; Cd-Zn, Cu-Zn, Pb-Cd, Pb-Cu, and Pb-Zn in sediment; and Cu-Pb, Cu-Zn, and Pb-Zn in S. plicata samples. Positive relationships between these metals showed that they were originated from same sources and that they were associated with each other. Based on the findings, Zn, Cu, and Pb concentrations in suspended particulate matters, sediments, and S. plicata samples were generally represented with higher levels at stations that were used for boating, shipping, and related activities. As S. plicata is a strongest accumulator of V, the relatively low V levels observed in this study may indicate the lack of anthropogenic sources of this metal in the sampling stations. In conclusion, suspended particulate matter and sediment can be useful tool to detect the pollution status of the marine environment. Furthermore, the findings of this study highlighted that S. plicata is a promising alternative for the monitoring of heavy metal pollution for eastern Aegean Sea coasts.

  20. Centennial-scale paleoceanography during sapropel S1 deposition in the NE Aegean (Mediterranean Sea)

    NASA Astrophysics Data System (ADS)

    Triantaphyllou, Maria; Gogou, Alexandra; Dimiza, Margarita; Kostopoulou, Sofia; Parinos, Constantine; Roussakis, Grigoris; Geraga, Maria; Skampa, Elisavet; Bouloubassi, Ioanna; Fleitmann, Dominik; Zervakis, Vassilis; Velaoras, Dimitris; Diamantopoulou, Antonia; Sampatakaki, Angeliki; Lykousis, Vassilis

    2016-04-01

    Combined micropaleontological and geochemical analyses in the high-sedimentation gravity core M-4G, provided new centennial scale paleoceanographic data for the sapropel S1 deposition in the NE Aegean Sea. Sapropel layer S1a (10.2-8.0 ka) is deposited in dysoxic to oxic bottom waters; sediments are characterized by the high abundance of benthic foraminifers Chilostomella mediterranensis and Globobulimina affinis that are able to tolerate surface sediment and/or pore water oxygen depletion and the presence of the oxic mesotrophic-eutrophic U. mediterranea. Adequate preservation of organic matter is proven by the high organic carbon and loliolide and isololiolide contents, whereas the biomarker record and the abundances of eutrophic planktonic foraminifera document enhanced productivity. Both alkenone-based SSTs and δO18 G. bulloides records indicate coolings at 8.2 ka (S1a) and at ~7.8 ka (S1 interruption). Sapropelic layer S1b (7.7-6.4 ka) is characterized by rather oxic conditions marked by the prominent increase of U. mediterranea. The highly fluctuating SSTs demonstrate repeated coolings and associated dense water formation; major event at 7.4 ka, followed by cold spells at 7.0, 6.8, 6.5 ka. Besides, the increase of algal biomarkers, labile organic matter-feeding foraminifera and eutrophic planktonic species pinpoints rise in in situ marine productivity, which is enhanced by more efficient vertical convection due to repeated cold events. The associated contributions of labile marine organic matter (OM) along with fresher terrestrial OM inputs after ~7.7 ka BP imply alternative/ additional than the north Aegean riverine borderland sources for the influx of organic matter at the south Limnos Basin, also related to the inflow of highly productive Marmara/Black Sea waters

  1. Performance of Statistical Temporal Downscaling Techniques of Wind Speed Data Over Aegean Sea

    NASA Astrophysics Data System (ADS)

    Gokhan Guler, Hasan; Baykal, Cuneyt; Ozyurt, Gulizar; Kisacik, Dogan

    2016-04-01

    Wind speed data is a key input for many meteorological and engineering applications. Many institutions provide wind speed data with temporal resolutions ranging from one hour to twenty four hours. Higher temporal resolution is generally required for some applications such as reliable wave hindcasting studies. One solution to generate wind data at high sampling frequencies is to use statistical downscaling techniques to interpolate values of the finer sampling intervals from the available data. In this study, the major aim is to assess temporal downscaling performance of nine statistical interpolation techniques by quantifying the inherent uncertainty due to selection of different techniques. For this purpose, hourly 10-m wind speed data taken from 227 data points over Aegean Sea between 1979 and 2010 having a spatial resolution of approximately 0.3 degrees are analyzed from the National Centers for Environmental Prediction (NCEP) The Climate Forecast System Reanalysis database. Additionally, hourly 10-m wind speed data of two in-situ measurement stations between June, 2014 and June, 2015 are considered to understand effect of dataset properties on the uncertainty generated by interpolation technique. In this study, nine statistical interpolation techniques are selected as w0 (left constant) interpolation, w6 (right constant) interpolation, averaging step function interpolation, linear interpolation, 1D Fast Fourier Transform interpolation, 2nd and 3rd degree Lagrange polynomial interpolation, cubic spline interpolation, piecewise cubic Hermite interpolating polynomials. Original data is down sampled to 6 hours (i.e. wind speeds at 0th, 6th, 12th and 18th hours of each day are selected), then 6 hourly data is temporally downscaled to hourly data (i.e. the wind speeds at each hour between the intervals are computed) using nine interpolation technique, and finally original data is compared with the temporally downscaled data. A penalty point system based on

  2. Foraminifera eco-biostratigraphy of the southern Evoikos outer shelf, central Aegean Sea, during MIS 5 to present

    NASA Astrophysics Data System (ADS)

    Drinia, Hara; Antonarakou, Assimina; Tsourou, Theodora; Kontakiotis, George; Psychogiou, Maria; Anastasakis, George

    2016-09-01

    The South Evoikos Basin is a marginal basin in the Aegean Sea which receives little terrigenous supply and its sedimentation is dominated by hemipelagic processes. Late Quaternary benthic and planktonic foraminifera from core PAG-155 are investigated in order to understand their response to the glacial-interglacial cycles in this region. The quantitative analysis of planktonic foraminifera, coupled with accelerator mass spectrometry (14C-AMS) radiocarbon date measurements, provide an integrated chrono-stratigraphic time framework over the last 90 ka (time interval between late Marine Isotopic Stages 5 and 1; MIS5-MIS1). The temporary appearance and disappearance as well as several abundance peaks in the quantitative distribution of selected climate-sensitive planktonic species allowed the identification of several eco-bioevents, useful to accurately mark the boundaries of the eco-biozones widely recognized in the Mediterranean records and used for large-scale correlations. The established bio-ecozonation scheme allows a detailed palaecological reconstruction for the late Pleistocene archive in the central Aegean, and furthermore provides a notable contribution for palaeoclimatic studies, facilitating intercorrelations between various oceanographic basins. The quantitative analyses of benthic foraminifera identify four distinct assemblages, namely Biofacies: Elphidium spp., Haynesina spp. Biofacies, characterized by neritic species, dominated during the transition from MIS 5 to MIS 4; Cassidulina laevigata/carinata Biofacies dominated till 42 ka (transgressive trend from MIS 4 to MIS 3); Bulimina gibba Biofacies dominated from 42 ka to 9.5 ka (extensive regression MIS 3,2 through lowstand and early transgression; beginning of MIS 1); Bulimina marginata, Uvigerina spp. Biofacies dominated from 9.5 ka to the present (late transgression through early highstand; MIS 1)., This study showed that the South Evoikos Basin which is characterized by its critical depths and

  3. The Sponge Community of a Subtidal Area with Hydrothermal Vents: Milos Island, Aegean Sea

    NASA Astrophysics Data System (ADS)

    Pansini, M.; Morri, C.; Bianchi, C. N.

    2000-11-01

    Sponges were sampled by SCUBA diving at six subtidal rocky sites, three of which were close to hydrothermal vents, a common feature on the sea-floor off the south-east coast of Milos. Twenty-five species (2 Calcarea and 23 Demospongiae) were found, few compared with the 589 recorded for the Mediterranean, but an important addition to the scant information on the sponge fauna of the Aegean Sea. The number of species found at vent sites was consistently higher than that found at non-vent sites, but no vent-obligate species could be identified. However, Geodia cydonium and three species of Cliona ( C. copiosa, C. nigricans and C. rhodensis) showed a tendency to colonize vent areas. The former might take advantage of increased silica availability, the latter of the enhanced deposition of carbonates near vents. Substratum cover by sponges (estimated from wire-framed photographs of 0·7 m 2), varied greatly both among and within sites, mostly according to slope. Most sponge species preferred vertical to overhanging, shaded substrata. Proximity to vents seemed to have little or no influence on sponge cover, notwithstanding a primary effect on species diversity.

  4. Long-Term Marine Traffic Monitoring for Environmental Safety in the Aegean Sea

    NASA Astrophysics Data System (ADS)

    Giannakopoulos, T.; Gyftakis, S.; Charou, E.; Perantonis, S.; Nivolianitou, Z.; Koromila, I.; Makrygiorgos, A.

    2015-04-01

    The Aegean Sea is characterized by an extremely high marine safety risk, mainly due to the significant increase of the traffic of tankers from and to the Black Sea that pass through narrow straits formed by the 1600 Greek islands. Reducing the risk of a ship accident is therefore vital to all socio-economic and environmental sectors. This paper presents an online long-term marine traffic monitoring work-flow that focuses on extracting aggregated vessel risks using spatiotemporal analysis of multilayer information: vessel trajectories, vessel data, meteorological data, bathymetric / hydrographic data as well as information regarding environmentally important areas (e.g. protected high-risk areas, etc.). A web interface that enables user-friendly spatiotemporal queries is implemented at the frontend, while a series of data mining functionalities extracts aggregated statistics regarding: (a) marine risks and accident probabilities for particular areas (b) trajectories clustering information (c) general marine statistics (cargo types, etc.) and (d) correlation between spatial environmental importance and marine traffic risk. Towards this end, a set of data clustering and probabilistic graphical modelling techniques has been adopted.

  5. Sea cliff erosion in the eastern part of the North Aegean coastline, Northern Greece.

    PubMed

    Xeidakis, George S; Delimani, P K; Skias, S G

    2006-01-01

    The coastal zone is an area where many human activities are taking place. Erosion of the coast obstructs, in various ways, these activities creating occasionally serious socioeconomic and environmental problems. In this paper the coastal erosion problems encountered in the eastern Greek part of the North Aegean Sea Coast, a stretch of about 51 km long adjacent to the city of Alexandroupolis, are discussed. Given the observed type and location of erosion and other sea-action phenomena, the coast under study is divided in two parts/stretches. The western stretch, where the city of Alexandroupolis is presently extending, presents, mainly, cliff erosion problems and retreat of the coastline, very serious in some sections; whereas, the eastern stretch (to the east of the city) exhibits deposition and progression seawards due to the abundance of sediments supplied by Evros river delta. A classification of the coastline according to its relief, geologic material, erosion characteristics and rate, slope failure phenomena as well as the wave energy potential, is presented together with suggestions for case-appropriate mitigation and protection measures regarding the coastal erosion problems. The paper is focusing on the cliff erosion phenomena, since varying in height coastal cliffs made of soft rocks, cover the major part of the investigated coastline (western stretch).

  6. Assessment of SMOS Salinity and SST in the Aegean Sea (Greece) and correlations with MODIS SST measurements. Exploring the SSS and SST correlation to 137Cs inventory

    NASA Astrophysics Data System (ADS)

    Sykioti, Olga; Florou, Heleni

    2014-05-01

    . Additionally, for the same coordinates and for the same acquisition dates, we have retrieved SST (both at 4μm and 11μm) from MODIS Level 2 Ocean products. MODIS satellites provide nearly daily ocean color and SST measurements at 1km resolution with day and night coverage. Therefore, separate correlations are performed for AQUA or TERRA and day or night passes (when data exist). Despite significant differences in spatial resolution and acquisition time in the day, results show high correlation coefficients (r2 above 80%) between SMOS and MODIS SST. Concluding, concerning SSS in regional seas such as the Aegean Sea, SMOS presents significant problems and difficulties to overcome. SSS comparisons with the corresponding AQUARIUS ones are foreseen. Concerning SST, values are highly correlated to similar ones from other satellite systems such as MODIS. Considering that SMOS acquisitions are insensitive to cloud cover and despite the relatively low spatial resolution, they present a considerable advantage compared to optical systems. This ongoing study is being carried out in NOA and NCSR "D" in the frame of the coordinated ESA Cat-1 Project AOSMOS.4681 which is acknowledged.

  7. Viability and Management Targets of Mediterranean Demersal Fisheries: The Case of the Aegean Sea

    PubMed Central

    Tserpes, George; Maravelias, Christos; Carvalho, Natacha; Merino, Gorka

    2016-01-01

    Management of the Mediterranean demersal stocks has proven challenging mainly due to the multi-species character of the fisheries. In the present work, we focus on the multi-species demersal fisheries of the Aegean Sea (eastern Mediterranean) aiming to study the effects of different management measures on the main commercial stocks, as well as to explore the economic viability of the fisheries depending upon these resources, by means of simulated projections. Utilizing the limited available data, our results demonstrated that, under the current exploitation pattern, the economic viability of the fleets is threatened, particularly if fuel prices increase. Additionally, the biological targets set for the most exploited species, such as hake, will not be met under the current management regime. The projections also showed that the only management scenario under which both resource sustainability and economic viability of the fisheries are ensured is the decrease of fleet capacity in terms of vessel numbers. In this case, however, measures to support the fisheries-dependent communities need to be implemented to prevent the collapse of local economies due to employment decrease. Scenarios assuming selectivity improvements would be also beneficial for the stocks but they showed low economic performance and their application would threaten the viability of the fleets, particularly that of the trawlers. PMID:28033348

  8. Polychaetes associated with the sciaphilic alga community in the northern Aegean Sea: spatial and temporal variability

    NASA Astrophysics Data System (ADS)

    Antoniadou, C.; Nicolaidou, A.; Chintiroglou, C.

    2004-10-01

    Polychaete biodiversity has received little attention despite its importance in biomonitoring. This study describes polychaete diversity, and its spatial and temporal variability in infralittoral, hard substrate assemblages. Seven stations were chosen in the central area of the northern Aegean Sea. At each station, one to three depth levels were set (15, 30 and 40 m). Five replicates were collected by scuba diving with a quadrat sampler (400 cm2) from each station and depth level during summer for the spatial analysis, and seasonally for the study of temporal changes. Common biocoenotic methods were employed (estimation of numerical abundance, mean dominance, frequency, Margalef's richness, Shannon-Weaver index and Pielou's evenness). A total of 5,494 individuals, belonging to 79 species, were counted and classified. Diversity indices were always high. Clustering and multidimensional scaling techniques indicated a high heterogeneity of the stations, although these were all characterized by the sciaphilic alga community. A clear seasonal pattern was not detectable. Summer and autumn samples discriminate, while winter and spring form an even group. The abundance/biomass comparison indicated a dominance of k-strategy patterns, characteristic of stable communities.

  9. Offshore wind speed and wind power characteristics for ten locations in Aegean and Ionian Seas

    NASA Astrophysics Data System (ADS)

    Bagiorgas, Haralambos S.; Mihalakakou, Giouli; Rehman, Shafiqur; Al-Hadhrami, Luai M.

    2012-08-01

    This paper utilizes wind speed data measured at 3 and 10 m above water surface level using buoys at 10 stations in Ionian and Aegean Seas to understand the behaviour of wind and thereafter energy yield at these stations using 5 MW rated power offshore wind turbine. With wind power densities of 971 and 693 W/m2 at 50 m above water surface level, Mykonos and Lesvos were found to be superb and outstanding windy sites with wind class of 7 and 6, respectively. Other locations like Athos, Santorini and Skyros with wind power density of more than 530 W/m2 and wind class of 5 were found to be the excellent sites. Around 15-16% higher winds were observed at 10 m compared to that at 3 m. Lower values of wind speed were found during summer months and higher during winter time in most of the cases reported in the present work. Slightly decreasing (~2% per year) linear trends were observed in annual mean wind speed at Lesvos and Santorini. These trends need to be verified with more data from buoys or from nearby onshore meteorological stations. At Athos and Mykonos, increasing linear trends were estimated. At all the stations the chosen wind turbine could produce energy for more than 70% of the time. The wind speed distribution was found to be well represented by Weibull parameters obtained using Maximum likelihood method compared to WAsP and Method of Moments.

  10. Macrobenthic community structure over the continental margin of Crete (South Aegean Sea, NE Mediterranean)

    NASA Astrophysics Data System (ADS)

    Tselepides, Anastasios; Papadopoulou, Konstantia-N.; Podaras, Dimitris; Plaiti, Wanda; Koutsoubas, Drosos

    2000-08-01

    Macrobenthic faunal composition, abundance, biomass and diversity together with a suite of sedimentary environmental parameters were investigated on a seasonal basis in order to determine factors regulating faunal distribution over the oligotrophic continental margin of the island of Crete (South Aegean Sea, North Eastern Mediterranean). Macrofaunal species composition was similar to that of the western Mediterranean and the neighboring Atlantic having several common dominant species. Mean benthic biomass, abundance and diversity decreased with depth, with a major transition zone occurring at 540 m, beyond which values declined sharply. At comparable depths biomass and abundance values were considerably lower to those found in the Atlantic, high-lighting the extreme oligotrophy of the area. The continental margin of Crete was characterised by a high diversity upper continental shelf environment (dominated by surface deposit feeding polychaetes) and a very low diversity slope and deep-basin environment (dominated by carnivorous and filter feeding polychaetes). Classification and ordination analyses revealed the existence of four principle clusters divided by a faunal boundary between 200 and 540 m, as well as beyond 940 m depth. Significant correlations between macrofauna and sediment parameters led to the conclusion that besides depth, food availability (as manifested by the concentration of chloroplastic pigments) is the principle regulating factor in the system. Such being the case, the prevailing hydrographic features that structure the pelagic food web and are directly responsible for the propagation of organic matter to the benthos also affect its community structure.

  11. Internal wave measurements on the Cycladic Plateau of the Aegean Sea

    NASA Astrophysics Data System (ADS)

    Alford, Matthew H.; Gregg, Michael C.; Zervakis, Vassilis; Kontoyiannis, Harialos

    2012-01-01

    The internal wave climate in the southern Aegean Sea is examined with an array of two bottom-mounted acoustic Doppler current profilers and three profiling moorings deployed on the northern continental slope of the Cretan Sea for 3 months. Frequency spectra indicate an extremely weak internal wave continuum, about 4-10 times weaker than the Garrett-Munk and Levine reference levels. Spectra are instead dominated by semidiurnal internal tides and near-inertial waves, which are examined in detail by bandpass filtering. In the semidiurnal band, a barotropic tidal flow of ≈2 cm s-1 is observed, with a pronounced spring/neap modulation in phase with the lunar fortnightly cycle. One to two days following several of these spring tide periods, a distinct internal tide featuring 10-20 m vertical displacements and 15-20 cm s-1baroclinic velocities is detectable propagating upward and to the southeast. Time-mean energy increases a factor of 2-5 within about 100 m from the bottom, implying generation and/or scattering from the bottom, whose slope is nearly critical to semidiurnal internal waves over much of the array. Several strong, downward propagating near-inertial events are also seen, each of which occurs following a period of work done by the wind on the mixed layer as estimated from a nearby surface mooring. The high-frequency internal wave continuum is more temporally constant but increases substantially toward the end of the deployment. Significant but unexplained differences in kinetic energy occur between successive spring tide periods in the case of the internal tides and between successive wind events in the case of the near-inertial signals. Substantial variability is observed in the low-frequency flows, which likely contributes to the time variability of the internal wave signals.

  12. Levels of (210)Po in some commercial fish species consumed in the Aegean Sea coast of Turkey and the related dose assessment to the coastal population.

    PubMed

    Aközcan, S

    2013-04-01

    Concentrations of (210)Po were determined in the edible muscle tissue of five species of marine fish: Sardine (Sardine plichardus) and Anchovy (Engraulis encrasicolus), Red mullet (Mullus barbatus), Horse mackerel (Trachurus trachurus) and Gilt-head sea bream (Sparus aurata) collected from five stations in the Aegean Sea Region of Turkey during the fishery season 2010. The (210)Po concentrations in the fish samples were found to vary from not detected levels to 389 ± 45 Bq kg(-1) dry wt. These variations in (210)Po content in different species are probably due to differences in metabolism and feeding patterns. The highest levels for (210)Po were observed in Anchovy (E. encrasicolus) species.

  13. Evolution and fluxes of 137Cs in the Black Sea/Turkish Straits System/North Aegean Sea

    NASA Astrophysics Data System (ADS)

    Delfanti, R.; Özsoy, E.; Kaberi, H.; Schirone, A.; Salvi, S.; Conte, F.; Tsabaris, C.; Papucci, C.

    2014-07-01

    The vertical profiles of 137Cs were determined in the North Aegean, Marmara and Black Seas, to assess inventories and fluxes of the radionuclide in these basins. The inventory of 137Cs in the Western Black Sea integrated from the surface down to 400 m water depth is 3.4 ± 0.1 kBq m- 2, which is surprisingly close to the amount determined in 1988, decay corrected to 2007 (2.9 ± 0.1 kBq m- 2). On the other hand, based on the comparison of profiles roughly 20 years apart, it is estimated that about 1 kBq m- 2 has been transferred from above the halocline to depths below the halocline, emphasizing the effective redistribution of tracers within the same period. We estimate that about 12 TBq y- 1 of 137Cs presently leaves the Black Sea with the upper layer flow through the Bosphorus and only 2 TBq y- 1 is returned with the lower layer inflow of Mediterranean water from the Marmara Sea. Accounting for river fluxes, estimated on the order of 2 TBq y- 1 few years after the Chernobyl accident, and possibly decreased by now, we can thus estimate a net rate of loss of about 8-10 TBq y- 1. Investigating the effective redistribution in the upper water column, the supply by the inflowing Mediterranean water alone does not explain the increase of 137Cs concentration and inventory at intermediate depths in the Western Black Sea. The most important mechanism transferring 137Cs and dissolved contaminants from the surface water to the sub-pycnocline layer appears to be the turbulent entrainment of a larger quantity of Black Sea water into the inflowing plume of Mediterranean water through mixing processes on the southwestern shelf and continental slope following its exit from the Bosphorus. This process produces an extra export of some10 TBq y- 1 of 137Cs from the surface to the sub-pycnocline depths of the Black Sea, a quantity comparable in magnitude to the total export out from the basin. It is the entrainment flux resulting from the mixing, and the further advection and

  14. Temporal patterns of detachment faulting along Cycladic extensional metamorphic domes, Aegean region

    NASA Astrophysics Data System (ADS)

    Schneider, D. A.; Grasemann, B.; Heizler, M.; Vogel, H.; Iglseder, C.

    2007-12-01

    The Aegean region together with the surrounding mainland areas are known for Miocene to Recent active, notably extensional tectonics that are the result of the retreating Hellenic slab, gravitational collapse of the region and, since the Late Miocene to Early Pliocene, the westward escape of Anatolia relative to Eurasia. Project ACCEL (Aegean Core Complexes along an Extended Lithosphere) has collected an extensive modern structural dataset for the islands of Kea, Kithnos, and Serifos of the western Cyclades. On all three islands, crustal-scale, low-angle frictional-viscous shear zones have been identified and record strikingly consistent SSW-directed extensional kinematics together with a WNE-ESE shortening component. The geology of Kea is dominated by highly-strained, greenschist-facies schists, calc-silicates and marbles; a major, 100's m thick ultramylonite zone defines this northern island as a structural dome. White mica Ar-Ar thermochronometry performed on variably deformed units from different structural levels yield consistent Early Miocene (15-19 Ma) cooling ages across the entire island. Other pervasively deformed shallow crustal regions of the Cyclades (Tinos and Andros; b-type domes of Jolivet et al. 2004) also record similar Early Miocene cooling. Comparable geology and structure is exposed on Serifos although locally deformed under amphibolite-facies conditions and intruded in the south by a Late Miocene granodiorite. A major high strain zone that is present on the island is localized along an earlier (Late Eocene) granitic pluton. White micas from mylonites and gneisses along this shear zone and from rocks in the southern portion of the island yield Late Miocene (8-9 Ma) cooling ages, whereas greenschist-facies units in northern Serifos that are dominated by a different structural record of several phases of folding yield Oligocene (30-34 Ma) mica Ar-Ar cooling ages. Oligocene ages are similarly reported from Evvia and Sifnos, which are noted for

  15. Estimation of relative humidity based on artificial neural network approach in the Aegean Region of Turkey

    NASA Astrophysics Data System (ADS)

    Yasar, Abdulkadir; Simsek, Erdoğan; Bilgili, Mehmet; Yucel, Ahmet; Ilhan, Ilhami

    2012-01-01

    The aim of this study is to estimate the monthly mean relative humidity (MRH) values in the Aegean Region of Turkey with the help of the topographical and meteorological parameters based on artificial neural network (ANN) approach. The monthly MRH values were calculated from the measurement in the meteorological observing stations established in Izmir, Mugla, Aydin, Denizli, Usak, Manisa, Kutahya and Afyonkarahisar provinces between 2000 and 2006. Latitude, longitude, altitude, precipitation and months of the year were used in the input layer of the ANN network, while the MRH was used in output layer of the network. The ANN model was developed using MATLAB software, and then actual values were compared with those obtained by ANN and multi-linear regression methods. It seemed that the obtained values were in the acceptable error limits. It is concluded that the determination of relative humidity values is possible at any target point of the region where the measurement cannot be performed.

  16. New particle formation in the southern Aegean Sea during the Etesians: importance for CCN production and cloud droplet number

    NASA Astrophysics Data System (ADS)

    Kalkavouras, Panayiotis; Bossioli, Elissavet; Bezantakos, Spiros; Bougiatioti, Aikaterini; Kalivitis, Nikos; Stavroulas, Iasonas; Kouvarakis, Giorgos; Protonotariou, Anna P.; Dandou, Aggeliki; Biskos, George; Mihalopoulos, Nikolaos; Nenes, Athanasios; Tombrou, Maria

    2017-01-01

    This study examines how new particle formation (NPF) in the eastern Mediterranean in summer affects CCN (cloud condensation nuclei) concentrations and cloud droplet formation. For this, the concentration and size distribution of submicron aerosol particles, along with the concentration of trace gases and meteorological variables, were studied over the central (Santorini) and southern Aegean Sea (Finokalia, Crete) from 15 to 28 July 2013, a period that includes Etesian events and moderate northern surface winds. Particle nucleation bursts were recorded during the Etesian flow at both stations, with those observed at Santorini reaching up to 1.5 × 104 particles cm-3; the fraction of nucleation-mode particles over Crete was relatively diminished, but a higher number of Aitken-mode particles were observed as a result of aging. Aerosol and photochemical pollutants covaried throughout the measurement period; lower concentrations were observed during the period of Etesian flow (e.g., 43-70 ppbv for ozone and 1.5-5.7 µg m-3 for sulfate) but were substantially enhanced during the period of moderate surface winds (i.e., increase of up to 32 for ozone and 140 % for sulfate). We find that NPF can double CCN number (at 0.1 % supersaturation), but the resulting strong competition for water vapor in cloudy updrafts decreases maximum supersaturation by 14 % and augments the potential droplet number only by 12 %. Therefore, although NPF events may strongly elevate CCN numbers, the relative impacts on cloud droplet number (compared to pre-event levels) is eventually limited by water vapor availability and depends on the prevailing cloud formation dynamics and the aerosol levels associated with the background of the region.

  17. Ductile nappe stacking and refolding in the Cycladic Blueschist Unit: insights from Sifnos Island (south Aegean Sea)

    NASA Astrophysics Data System (ADS)

    Aravadinou, Eirini; Xypolias, Paraskevas; Chatzaras, Vasileios; Iliopoulos, Ioannis; Gerogiannis, Nikolaos

    2016-10-01

    New geological and structural mapping combined with kinematic and amphibole chemistry analyses is used to investigate the deformation history of the Cycladic Blueschist Unit (CBU) on Sifnos Island (Cyclades, Aegean Sea). We concentrate on north Sifnos, an area characterized by exceptionally well-preserved eclogites and blueschists. Our data show that the early, main phase (D2) of ductile deformation in the CBU occurred synchronous with the transition from prograde to close-to-peak retrograde conditions. This deformation phase took place at middle Eocene and is related to ESE-directed thrusting that emplaced the metavolcano-sedimentary subunit over the Marble subunit. The subsequent exhumation-related (D3) deformation is characterized by gently NE-plunging folds and NE-directed contractional shear zones that formed parallel to the axial planes of folds. NE-directed shearing occurred under blueschist and transitional blueschist-/greenschist-facies conditions during late Eocene-Oligocene and caused the restacking of the early nappe pile. We suggest that a mechanism of ductile extrusion of the CBU in a tectonic setting of net compression could explain better the recorded exhumation-related deformation than a mechanism of syn- and post-orogenic extension. Our new kinematic results in combination with previous works in the Cyclades area reveal a regional scale change in tectonic transport direction from (W)NW-(E)SE at Late Cretaceous-middle Eocene to (E)NE-(W)SW at late Eocene-Oligocene times. The observed change in transport direction may be governed by the relative motion of Africa with respect to Europe during Alpine orogeny.

  18. Particulate organic carbon export fluxes and size-fractionated POC/ 234Th ratios in the Ligurian, Tyrrhenian and Aegean Seas

    NASA Astrophysics Data System (ADS)

    Speicher, E. A.; Moran, S. B.; Burd, A. B.; Delfanti, R.; Kaberi, H.; Kelly, R. P.; Papucci, C.; Smith, J. N.; Stavrakakis, S.; Torricelli, L.; Zervakis, V.

    2006-11-01

    Measurements of 234Th/ 238U disequilibria and particle size-fractionated (1, 10, 20, 53, 70, 100 μm) organic C and 234Th were made to constrain estimates of the export flux of particulate organic C (POC) from the surface waters of the Ligurian, Tyrrhenian and Aegean Seas in March-June 2004. POC exported from the surface waters (75-100 m depth) averaged 9.2 mmol m -2 d -1 in the Ligurian and Tyrrhenian Seas (2.3±0.5-14.9±3.0 mmol m -2 d -1) and 0.9 mmol m -2 d -1 in the Aegean Sea. These results are comparable to previous measurements of 234Th-derived and sediment-trap POC fluxes from the upper 200 m in the Mediterranean Sea. Depth variations in the POC/ 234Th ratio suggest two possible controls. First, decreasing POC/ 234Th ratios with depth were attributed to preferential remineralization of organic C. Second, the occurrence of maxima or minima in the POC/ 234Th ratio near the DCM suggests influence by phytoplankton dynamics. To assess the accuracy of these data, the empirical 234Th-method was evaluated by quantifying the extent to which the 234Th-based estimate of POC flux, PPOC, deviates from the true flux, FPOC, defined as the p-ratio ( p-ratio= PPOC/FPOC= STh/SPOC, where S=particle sinking rate). Estimates of the p-ratio made using Stokes' Law and the particle size distributions of organic C and 234Th yield values ranging from 0.93-1.45. The proximity of the p-ratio to unity implies that differences in the sinking rates of POC- and 234Th-carrying particles did not bias 234Th-normalized POC fluxes by more than a factor of two.

  19. Seismicity and active tectonics at Coloumbo Reef (Aegean Sea, Greece): Monitoring an active volcano at Santorini Volcanic Center using a temporary seismic network

    NASA Astrophysics Data System (ADS)

    Dimitriadis, I.; Karagianni, E.; Panagiotopoulos, D.; Papazachos, C.; Hatzidimitriou, P.; Bohnhoff, M.; Rische, M.; Meier, T.

    2009-02-01

    western termination of the major ENE-WSW Santorini-Amorgos Fault Zone. Stress-tensor inversion of the available fault plane solutions from Coloumbo Reef, as well as existing neotectonic fault information from NE Santorini (Coloumbo peninsula), suggests that the NE Santorini-Coloumbo faults belong to a single rupture system, with a ~ 30° rotation of the local stress field with respect to the NNW-SSE regional extension field of the southern Aegean Sea. The observed change of the fault plane solutions shows that local conditions at the Coloumbo submarine volcano area control the observed faulting pattern.

  20. Assessment of island beach erosion due to sea level rise: the case of the Aegean archipelago (Eastern Mediterranean)

    NASA Astrophysics Data System (ADS)

    Monioudi, Isavela N.; Velegrakis, Adonis F.; Chatzipavlis, Antonis E.; Rigos, Anastasios; Karambas, Theophanis; Vousdoukas, Michalis I.; Hasiotis, Thomas; Koukourouvli, Nikoletta; Peduzzi, Pascal; Manoutsoglou, Eva; Poulos, Serafim E.; Collins, Michael B.

    2017-03-01

    The present contribution constitutes the first comprehensive attempt to (a) record the spatial characteristics of the beaches of the Aegean archipelago (Greece), a critical resource for both the local and national economy, and (b) provide a rapid assessment of the impacts of the long-term and episodic sea level rise (SLR) under different scenarios. Spatial information and other attributes (e.g., presence of coastal protection works and backshore development) of the beaches of the 58 largest islands of the archipelago were obtained on the basis of remote-sensed images available on the web. Ranges of SLR-induced beach retreats under different morphological, sedimentological and hydrodynamic forcing, and SLR scenarios were estimated using suitable ensembles of cross-shore (1-D) morphodynamic models. These ranges, combined with empirically derived estimations of wave run-up induced flooding, were then compared with the recorded maximum beach widths to provide ranges of retreat/erosion and flooding at the archipelago scale. The spatial information shows that the Aegean pocket beaches may be particularly vulnerable to mean sea level rise (MSLR) and episodic SLRs due to (i) their narrow widths (about 59 % of the beaches have maximum widths < 20 m), (ii) their limited terrestrial sediment supply, (iii) the substantial coastal development and (iv) the limited existing coastal protection. Modeling results indeed project severe impacts under mean and episodic SLRs, which by 2100 could be devastating. For example, under MSLR of 0.5 m - representative concentration pathway (RCP) 4.5 of the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate change (IPCC) - a storm-induced sea level rise of 0.6 m is projected to result in a complete erosion of between 31 and 88 % of all beaches (29-87 % of beaches are currently fronting coastal infrastructure and assets), at least temporarily. Our results suggest a very considerable risk which will require significant

  1. April 16, 2015 Crete Island Earthquake (Mw=5.9) Series and its Seismotectonic Significance, Southern Aegean Sea

    NASA Astrophysics Data System (ADS)

    Yalçın, Hilal; Kürçer, Akın; Gülen, Levent

    2016-04-01

    The active deformation of the southern Aegean Sea is a result of the northward motion of the African and Arabian Plates with respect to the Eurasian Plate in the Eastern Mediterranean Region. The Hellenic subduction zone plays a key role in the active tectonics of the region. On 16 April, 2015, a moderate earthquake occurred on the eastern part of Hellenic arc (south of Crete island), with a moment magnitude of Mw=5.9. A series of aftershocks were occurred within four months following the mainshock, which have magnitudes varying from Mw = 3.4 to 5.4. Source parameters of the 16 April 2015 earthquake have been modeled in order to reveal the regional stress tensor and the tectonic style of the region. In this study, the source parameters of the main shock and 36 aftershocks that have magnitudes M≥3.4 have been determined and modeled by seismic moment tensor waveform inversion method developed by Sokos and Zahradnik (2006) algorithm using the near-field and regional waveforms. The depth of earthquakes are varied from 2 to 61 km. Stress tensor can describe reliably principle stress axes (σ1, σ2, σ3), their relative size and stress field variations. Stress tensor inversions have been carried out using the Micheal method (1984, 1987). In this study, 16 April 2015 Crete Earthquake mainshock (Mw=5.9), a total of 36 earthquake moment tensor solutions that belong to the Crete earthquake sequence and 24 earthquake moment tensor solutions of previous main shocks in the region have been compiled and used in the stress inversion calculation. Orientations of σ1, σ2 and σ3 were computed and the principal directions are projected onto a lower hemisphere Wulff net. The best fit was attained for Phi = 0.38+/-0.13609 and indicated that the stress regime revealed strike-slip faulting with reverse component and for the azimuth and plunge pair of (-161.6°, 21.7°) for σ1, (-11.1°, 65.4°) for σ2 and (103.8°, 10.9°) for σ3. At the final step of the study, Gutenberg and

  2. Geochemistry of natural and anthropogenic metals in the coastal sediments of the island of Lesvos, Aegean Sea.

    PubMed

    Aloupi, M; Angelidis, M O

    2001-01-01

    The geochemistry of metals in the harbor and coastal zone of the town of Mytilene (island of Lesvos, Aegean Sea, Greece) was studied after normalization of the metal data to a conservative element. In the study area, Li was proven to be better suited than Al for such normalization and it was able to describe successfully the natural metal variability of the coastal sediments. Metal contamination (Cd, Cu, Pb, Zn) was recorded in the harbor sediments, while no pollution signs were detected in the wider coastal zone or the sediments of the ancient harbor, at the northern part of the town. The geochemical normalization of metal data to Li is a method that can detect the degree of metal contamination taking into consideration the natural metal variability in the sediments of a study area.

  3. Potential Health Hazard Assessment in Terms of Some Heavy Metals Determined in Demersal Fishes Caught in Eastern Aegean Sea.

    PubMed

    Yabanli, Murat; Alparslan, Yunus

    2015-10-01

    A heavy metal risk assessment based on estimated daily intake (EDI) and target hazard quotient was made for children and adults. Five fish species captured from the eastern Aegean Sea were analyzed for Cr, Cu, Cd, Hg and Pb by inductively coupled plasma spectroscopy in muscle tissue of red mullet (Mullus barbatus), surmullet (Mullus surmuletus), sand steenbras (Lithognathus mormyrus), common two-banded seabream (Diplodus vulgaris) and common pandora (Pagellus erythinus). The ranges for mean metal concentration (mg/kg wet wt) in the five species were 0.27-0.39 Cr, 0.12-0.22 Cu, 0.09-0.10 Hg and 0.10-0.12 Pb. All means were identical for Cd at 0.03 mg/kg wet wt. The EDI values for each metal were ascertained not to exceed the tolerable daily intake amount. Fish did not contain sufficiently high levels of these metals to pose a carcinogenic risk.

  4. Implementation of a reduced order Kalman filter to assimilate ocean color data into a coupled physical-biochemical model of the North Aegean Sea.

    NASA Astrophysics Data System (ADS)

    Kalaroni, Sofia; Tsiaras, Kostas; Economou-Amilli, Athena; Petihakis, George; Politikos, Dimitrios; Triantafyllou, George

    2013-04-01

    Within the framework of the European project OPEC (Operational Ecology), a data assimilation system was implemented to describe chlorophyll-a concentrations of the North Aegean, as well the impact on the European anchovy (Engraulis encrasicolus) biomass distribution provided by a bioenergetics model, related to the density of three low trophic level functional groups of zooplankton (heterotrophic flagellates, microzooplankton and mesozooplankton). The three-dimensional hydrodynamic-biogeochemical model comprises two on-line coupled sub-models: the Princeton Ocean Model (POM) and the European Regional Seas Ecosystem Model (ERSEM). The assimilation scheme is based on the Singular Evolutive Extended Kalman (SEEK) filter and its variant that uses a fixed correction base (SFEK). For the initialization, SEEK filter uses a reduced order error covariance matrix provided by the dominant Empirical Orthogonal Functions (EOF) of model. The assimilation experiments were performed for year 2003 using SeaWiFS chlorophyll-a data during which the physical model uses the atmospheric forcing obtained from the regional climate model HIRHAM5. The assimilation system is validated by assessing the relevance of the system in fitting the data, the impact of the assimilation on non-observed biochemical parameters and the overall quality of the forecasts.

  5. Recurrent intrusions of transitional waters of Eastern Mediterranean origin in the Cretan Sea as a tracer of Aegean Sea dense water formation events

    NASA Astrophysics Data System (ADS)

    Velaoras, Dimitris; Krokos, George; Theocharis, Alexander

    2015-06-01

    Available temperature and salinity data in the Cretan Sea from 1955 up to 2014 as well as literature sources were revisited in order to trace the appearance of low salinity, temperature, oxygen and nutrient-rich waters inside the basin at depths below the intermediate layer. First appearing as far back as 1961 in literature, these waters were found originating in the layers that separate intermediate and deep waters of the Eastern Mediterranean Sea (EMed) and were named Transitional Mediterranean Water (TMW) in the 1990s. Data analysis showed that the appearance of TMW in the Cretan Sea is a recurrent phenomenon connected to water mass exchanges between the Aegean Sea and the EMed. In particular, the inflow of TMW in the Cretan basin acts as compensation for the outflow of equally dense or denser masses from the Aegean. This export is a result of dense water formation (DWF) events taking place inside the Aegean Sea triggering TMW compensatory inflow into the Cretan Sea through the Cretan Straits. In this context, TMW intrusions in the Cretan basin can be used as a tracer of DWF in the Aegean Sea while the depth of the intrusion can provide valuable information about the intensity of the DWF event. The importance of TMW intrusions is not solely restricted to the tracing and evaluation of DWF events but could additionally expand to the impact on local ecological processes as TMW is a nutrient carrier for the oligotrophic Cretan Sea. It is obvious that this low salinity, temperature and oxygen layer is what was later named TMW. The core temperature, salinity and oxygen values reported by Miller (1974) fall within the range of values observed during the PELAGOS project in 1994, as noted in Section 'Presence of low salinity water masses below the intermediate layer in the Cretan Sea during the EMT event'. Using the same dataset provided by MEDATLAS 2002 database, a salinity transect along the Cretan Sea is reconstructed in Fig. 5. The bottle data originate from the

  6. Chemical properties and fluorescence of DOM in relation to biodegradation in the interconnected Marmara-North Aegean Seas during August 2008

    NASA Astrophysics Data System (ADS)

    Zeri, C.; Beşiktepe, Ş.; Giannakourou, A.; Krasakopoulou, E.; Tzortziou, M.; Tsoliakos, D.; Pavlidou, A.; Mousdis, G.; Pitta, E.; Scoullos, M.; Papathanassiou, E.

    2014-07-01

    The dynamics of dissolved organic matter (DOM) in the Marmara Sea-Dardanelles Straits-North Aegean Sea were investigated using measurements of dissolved organic carbon and nitrogen (DOC, DON), PARAFAC modeling of 3-D excitation-emission fluorescence spectra and bacterial production (BP) and respiration (BR) rates. In the surface brackish waters, chemical parameters showed an increase from the Aegean to the Marmara (DOC: 65-217 μmol L- 1; DON: 3.08-9.34 μmol L- 1; Dissolved Inorganic Nitrogen (DIN): 0.044-1.38), followed by an increase in BP rates (7.2-195 nmol L- 1 d- 1). In the subsurface waters, DIN also showed an increase in the Marmara basin (0.085-9.79 μmol L- 1) followed by an increase in BP rates (3.3-17.4 nmol L- 1 d- 1). PARAFAC modeling revealed three fluorescent components: λex/λem: < 260(330)/464 nm, humic-like; λex/λem: <(260) 285/364 nm, quinone-like; λex/λem: 270/308 nm, tyrosine-like. DOC:DON ratios were found similar for the Marmara (21 ± 3) and the N. Aegean Sea (19 ± 2). The slopes ΔDOC:ΔDON suggested that in the Marmara Sea mineralization processes require more carbon relative to nitrogen (22.3), whereas in the N. Aegean there is preferential removal of nitrogen over carbon (5.66). The lack of significant correlation between DOC and AOU (apparent oxygen utilization) in the deep Marmara waters indicates that particulate organic matter is important in deep mineralization processes.

  7. Old stories and lost pieces of the Eastern Mediterranean puzzle: a new approach to the tectonic evolution of the Western Anatolia and the Aegean Sea

    NASA Astrophysics Data System (ADS)

    Yaltırak, Cenk; Engin Aksu, Ali; Hall, Jeremy; Elitez, İrem

    2015-04-01

    During the last 20 or so years, the tectonic evolution of Aegean Sea and Western Anatolia has been dominantly explained by back-arc extension and escape tectonics along the North Anatolian Fault. Various datasets have been considered in the construction of general tectonic models, including the geometry of fault patterns, paleomagnetic data, extensional directions of the core complexes, characteristic changes in magmatism and volcanism, the different sense of Miocene rotation between the opposite sides of the Aegean Sea, and the stratigraphy and position of the Miocene and Pliocene-Quaternary basins. In these models, the roles of the Burdur-Fethiye Shear Zone, the Trakya-Eskişehir Fault Zone, the Anaximander Mountains and Isparta Angle have almost never been taken into consideration. The holistic evaluation of numerous land and marine researches in the Aegean Sea and western Anatolia suggest the following evolutionary stages: 1. during the early Miocene, Greece and western Anatolia were deformed under the NE-SW extensional tectonics associated with the back-arc extension, when core complexes and supra-detachment basins developed, 2. following the collision of the Anaximander Mountains and western Anatolia in early Miocene , the Isparta Angle locked this side of the western arc by generating a triangle-shaped compressional structure, 3. while the Isparta Angle penetrated into the Anatolia, the NE-striking Burdur-Fethiye Shear Zone in the west and NW-striking Trakya-Eskişehir Fault Zone in the north developed along the paleo-tectonic zones , 4. the formation of these two tectonic structures allowed the counterclockwise rotation of the western Anatolia in the middle Miocene and this rotation removed the effect of the back-arc extension on the western Anatolian Block, 5. the counterclockwise rotation developed with the early westward escape of the Western Anatolian reached up to 35-40o and Trakya-Eskişehir Fault Zone created a total dextral displacement of about 200

  8. Review of variations in Mw < 7 earthquake motions on position and TEC (Mw = 6.5 Aegean Sea earthquake sample)

    NASA Astrophysics Data System (ADS)

    Yildirim, Omer; Inyurt, Samed; Mekik, Cetin

    2016-02-01

    Turkey is a country located in the middle latitude zone, where tectonic activity is intensive. Recently, an earthquake of magnitude 6.5 Mw occurred offshore in the Aegean Sea on 24 May 2014 at 09:25 UTC, which lasted about 40 s. The earthquake was also felt in Greece, Romania, and Bulgaria in addition to Turkey. In recent years, ionospheric anomaly detection studies have been carried out because of seismicity with total electron content (TEC) computed from the global navigation satellite system's (GNSS) signal delays and several interesting findings have been published. In this study, both TEC and positional variations have been examined separately following a moderate size earthquake in the Aegean Sea. The correlation of the aforementioned ionospheric variation with the positional variation has also been investigated. For this purpose, a total of 15 stations was used, including four continuously operating reference stations in Turkey (CORS-TR) and stations in the seismic zone (AYVL, CANA, IPSA, and YENC), as well as international GNSS service (IGS) and European reference frame permanent network (EPN) stations. The ionospheric and positional variations of the AYVL, CANA, IPSA, and YENC stations were examined using Bernese v5.0 software. When the precise point positioning TEC (PPP-TEC) values were examined, it was observed that the TEC values were approximately 4 TECU (total electron content unit) above the upper-limit TEC value at four stations located in Turkey, 3 days before the earthquake at 08:00 and 10:00 UTC. At the same stations, on the day before the earthquake at 06:00, 08:00, and 10:00 UTC, the TEC values were approximately 5 TECU below the lower-limit TEC value. The global ionosphere model TEC (GIM-TEC) values published by the Centre for Orbit Determination in Europe (CODE) were also examined. Three days before the earthquake, at all stations, it was observed that the TEC values in the time period between 08:00 and 10:00 UTC were approximately 2 TECU

  9. Review of variations in Mw < 7 earthquake motions on position and tec (Mw = 6.5 aegean sea earthquake sample)

    NASA Astrophysics Data System (ADS)

    Yildirim, O.; Inyurt, S.; Mekik, C.

    2015-10-01

    Turkey is a country located in Middle Latitude zone and in which tectonic activity is intensive. Lastly, an earthquake of magnitude 6.5Mw occurred at Aegean Sea offshore on date 24 May 2014 at 12:25 UTC and it lasted approximately 40 s. The said earthquake was felt also in Greece, Romania and Bulgaria in addition to Turkey. In recent years seismic origin ionospheric anomaly detection studies have been done with TEC (Total Electron Contents) generated from GNSS (Global Navigation Satellite System) signals and the findings obtained have been revealed. In this study, TEC and positional variations have been examined seperately regarding the earthquake which occurred in the Aegean Sea. Then The correlation of the said ionospheric variation with the positional variation has been investigated. For this purpose, total fifteen stations have been used among which the data of four numbers of CORS-TR stations in the seismic zone (AYVL, CANA, IPSA, YENC) and IGS and EUREF stations are used. The ionospheric and positional variations of AYVL, CANA, IPSA and YENC stations have been examined by Bernese 5.0v software. When the (PPP-TEC) values produced as result of the analysis are examined, it has been understood that in the four stations located in Turkey, three days before the earthquake at 08:00 and 10:00 UTC, the TEC values were approximately 4 TECU above the upper limit TEC value. Still in the same stations, one day before the earthquake at 06:00, 08:00 and 10:00 UTC, it is being shown that the TEC values were approximately 5 TECU below the lower limit TEC value. On the other hand, the GIM-TEC values published by the CODE center have been examined. Still in all stations, it has been observed that three days before the earthquake the TEC values in the time portions of 08:00 and 10:00 UTC were approximately 2 TECU above, one day before the earthquake at 06:00, 08:00 and 10:00 UTC, the TEC values were approximately 4 TECU below the lower limit TEC value. Again, by using the same

  10. Aquatic animal resources in Prehistoric Aegean, Greece.

    PubMed

    Mylona, Dimitra

    2014-12-01

    This paper explores the early stages in the history of fishing in the Aegean Sea in Greece, and highlights its formative phases and its specific characteristics in different points in time. This is testified by various physical remains, such as fish bones, fishing tools, and representations in art, which are gathered in the course of archaeological research. The aquatic resources in the Aegean Sea have been exploited and managed for millennia by communities that lived near the water and often made a living from it. The earliest evidence for a systematic, intensive exploitation of marine resources in the Aegean Sea dates to the Mesolithic, eleven millennia ago. In the Neolithic period, the adoption of a sedentary, agro-pastoral way of life led to a reduction in the intensity of fishing and shellfish gathering. Its importance as an economic resource remained high only in certain regions of rich, eutrophic waters. In the Bronze Age, an era of social complexity and centralized economy, the exploitation of aquatic, mostly marine, resources became a complex, multi-faceted activity which involved subsistence, industry and ideology. The range of preferred fish and invertebrate species, the fishing technology, and the processing of fish and shellfish in order to produce elaborate foods or prestige items are all traceable aspects of the complex relationship between humans and the aquatic resources throughout the prehistory of fishing and shellfish gathering in the Aegean area. The broadening of collaboration between archaeology and physical sciences offers new means to explore these issues in a more thorough and nuanced manner.

  11. Marine pollution risk in a coastal city: use of an eco-genotoxic tool as a stress indicator in mussels from the Eastern Aegean Sea.

    PubMed

    Kacar, Asli; Pazi, Idil; Gonul, Tolga; Kucuksezgin, Filiz

    2016-08-01

    Coastal areas, such as bays, estuaries, and harbors, are heavily polluted since these areas are the settlements to which toxic chemicals from industrial and domestic wastes are discharged. The genetic damage was evaluated using bioindicator mussel Mytilus galloprovincialis caused by toxic chemicals (metals and polycyclic aromatic hydrocarbons) in İzmir and Çandarlı Bays (the Eastern Aegean Sea) through comet assay. Three sampling sites from the two bays were selected and the study was conducted during the spring and autumn periods. The highest levels of DNA damage expressed as %Tail-DNA were observed in İzmir Bay (34.60 % Tail-DNA) in the spring. Analysis of the correlation between PAHs and metals in mussels and %T-DNA in the hemolymph and gill cells showed a statistically significant positive correlation between %T-DNA and ∑PAH, chromium (p < 0.05). This study determined the pollution level of the İzmir and Çandarlı Bays by using the DNA damage to the mussel, which can identify the effects of environmental pollutants at the cellular levels. These results confirm that comet assay can be used to determine the temporal and spatial differences of DNA damage, and as a suitable tool for the measurement of genotoxicity in regions with low pollutant concentrations.

  12. Temporal trends of some trace metals in Lithophaga lithophaga (L., 1758) from Izmir Bay (Eastern Aegean Sea).

    PubMed

    Ozsuer, Meral; Sunlu, Ugur

    2013-10-01

    This study compared the levels of the trace metals zinc (Zn), cadmium (Cd), lead (Pb) and copper (Cu) in the bivalve Lithophaga lithophaga from Izmir Bay (Aegean Sea) between 2001 and 2011. Comparisons were made on the basis of season, as well as year. All values were measured by voltammetry. Median values of trace metals for all seasons in 2011 were 244.67 μg Zn g(-1), 1.09 μg Cd g(-1), 7.64 μg Pb g(-1) and 56.03 μg Cu g(-1) as dry weight. The results showed a general trend of decreasing Zn, Pb and Cu concentrations over time, but an increasing trend for Cd. Mean trace metal concentrations in individuals of L. lithophaga in 2011 exceeded the permissible limit published in the Turkish Food Codex for Pb, and closely approached the limit for Zn. The mean Cd concentration was within the permissible limit of the Turkish Food Codex, but exceeded the limit of the World Health Organization. Levels of Cu were within permissible limits of published regulations.

  13. Hydrodynamic features of the South Aegean Sea as derived from Argo T/ S and dissolved oxygen profiles in the area

    NASA Astrophysics Data System (ADS)

    Kassis, Dimitris; Krasakopoulou, Evangelia; Korres, Gerasimos; Petihakis, George; Triantafyllou, George S.

    2016-11-01

    In this work, the hydrodynamic picture of the South Aegean Sea is examined through an analysis of recent measurements in its sub-basins, the Myrtoan and Cretan Sea. Both sub-basins play an important role in the water circulation, exchange, and formation processes that affect the dynamics of the whole Eastern Mediterranean. For the first time, Bio-Argo floats were deployed in the area under the Greek Argo Research Infrastructure coordination. The acquired profiles cover an almost 2-year period (November 2013-July 2015) and are compared with previous Argo profiles and the re-processed time-series data recorded from the E1-M3A POSEIDON observatory operating in the area since 2007. The spatio-temporal distribution of the physical and chemical properties in each sub-basin is examined. Dense water formation events are revealed in the northern part (Myrtoan), while the wider area can be characterized as pre-conditioned. In the Cretan basin, a strong inter-annual variability of the salinity field at intermediate and deep layers is observed that is associated with water exchange from its open boundaries. Furthermore, comparison of the dissolved oxygen (DO) distribution with physical water properties within both the mixed layer, and at greater depths, indicated that relatively high but still under-saturated DO values are more likely to be associated with convection events. Finally, an updated picture of the physical properties and the DO distribution is presented based on the last 5 years of measurements and the recent introduction of Bio-Argo floats with DO sensors in the area.

  14. Geographic patterns of elemental deposition in the Aegean region of Turkey indicated by the lichen, Xanthoria parietina (L.) Th. Fr.

    PubMed

    Yenisoy-Karakaş, S; Tuncel, S G

    2004-08-15

    Lichen samples from different parts of the world have been known to accumulate elements to a greater degree than higher plants, if they are exposed to these elements from the atmosphere or from water and sediments. It has been hypothesized that lichens can be used to monitor air pollution around point and area emission sources. Local variation (variation in substrate, age and morphology of lichen samples) of element concentrations would not be large enough to affect the concentration patterns in large areas. We tested this hypothesis in the Aegean region of Turkey, which is very urbanized and industrialized. No such study has been conducted before in this part of the country. A total of 234 samples of the lichen Xanthoria parietina were collected from a 51,800-km2 area. Samples were washed and analyzed by INAA and ICP-AES for 35 elements. The range of the concentrations for most of the elements on a local scale was an order of magnitude lower than for the element concentrations on a regional scale. The mean local coefficient of variance (CV) was found to be 15, providing that the local variation did not affect the concentration of elements in the sampling region. According to cluster analysis, 8 (As, Hg, Pb, Sb, Fe, Mn, Na and K) elements are indicative of important local pollution locations and their zone of impact in the region. By mapping the concentrations of eight indicative elements in lichen Xanthoria parietina of the Aegean region, it was possible to relate deposition to the existence of known sources of pollution in certain areas. Location of pollution sources such as iron-steel plants, and coal burning in the cities, industrial activity and two important coal-fired power plants generally corresponded with locations of highest element accumulations in the lichens.

  15. Source of the tsunami generated by the 1650 AD eruption of Kolumbo submarine volcano (Aegean Sea, Greece)

    NASA Astrophysics Data System (ADS)

    Ulvrova, Martina; Paris, R.; Nomikou, P.; Kelfoun, K.; Leibrandt, S.; Tappin, D. R.; McCoy, F. W.

    2016-07-01

    The 1650 AD explosive eruption of Kolumbo submarine volcano (Aegean Sea, Greece) generated a destructive tsunami. In this paper we propose a source mechanism of this poorly documented tsunami using both geological investigations and numerical simulations. Sedimentary evidence of the 1650 AD tsunami was found along the coast of Santorini Island at maximum altitudes ranging between 3.5 m a.s.l. (Perissa, southern coast) and 20 m a.s.l. (Monolithos, eastern coast), corresponding to a minimum inundation of 360 and 630 m respectively. Tsunami deposits consist of an irregular 5 to 30 cm thick layer of dark grey sand that overlies pumiceous deposits erupted during the Minoan eruption and are found at depths of 30-50 cm below the surface. Composition of the tsunami sand is similar to the composition of the present-day beach sand but differs from the pumiceous gravelly deposits on which it rests. The spatial distribution of the tsunami deposits was compared to available historical records and to the results of numerical simulations of tsunami inundation. Different source mechanisms were tested: earthquakes, underwater explosions, caldera collapse, and pyroclastic flows. The most probable source of the 1650 AD Kolumbo tsunami is a 250 m high water surface displacement generated by underwater explosion with an energy of 2 × 1016 J at water depths between 20 and 150 m. The tsunamigenic explosion(s) occurred on September 29, 1650 during the transition between submarine and subaerial phases of the eruption. Caldera subsidence is not an efficient tsunami source mechanism as short (and probably unrealistic) collapse durations (< 5 min) are needed. Pyroclastic flows cannot be discarded, but the required flux (106 to 107 m3 · s- 1) is exceptionally high compared to the magnitude of the eruption.

  16. Source of the tsunami generated by the 1650 AD eruption of Kolumbo submarine volcano (Aegean Sea, Greece)

    NASA Astrophysics Data System (ADS)

    Ulvrova, Martina; Paris, Raphael; Nomikou, Paraskevi; Tappin, Dave

    2016-04-01

    The 1650 AD explosive eruption of Kolumbo submarine volcano (Aegean Sea, Greece) generated a destructive tsunami. In this paper we propose a source mechanism of this poorly documented tsunami using both geological investigations and numerical simulations. Sedimentary evidences of the 1650 AD tsunami were found along the coast of Santorini Island at maximum altitudes ranging between 3.5 m a.s.l. (Perissa, southern coast) and 20 m a.s.l. (Monolithos, eastern coast), corresponding to a minimum inundation of 360 and 630 m respectively. Tsunami deposits correspond to an irregular 5 to 30 cm thick layer of dark grey sand intercalated in soil at depths between 30 and 50 cm. Composition of the tsunami sand is similar to the composition of the present-day beach and clearly differs from the pumiceous gravelly soil. Spatial distribution of the tsunami deposits was confronted to available historical records and to the results of numerical simulations of tsunami inundation. Different scenarios of source mechanism were tested: earthquakes, underwater explosions, caldera collapse, and pyroclastic flows. The most probable source of the 1650 AD Kolumbo tsunami is a 250 m high water surface displacement generated by underwater explosion with an energy of ~2 E15 J at water depths between 20 and 150 m. The tsunamigenic explosion(s) occurred on September 29, 1650 during the transition between submarine and subaerial phases. Caldera subsidence is not an efficient source of tsunami, as short (and probably unrealistic) collapse durations (< 5 minutes) are needed. Pyroclastic flows cannot be discarded, but the required flux (E6 to E7 m³.s-1) is exceptionally high compared to the magnitude of the eruption.

  17. Radiometric dating of sediment cores from a hydrothermal vent zone off Milos Island in the Aegean Sea.

    PubMed

    Ugur, Aysun; Miquel, Juan-Carlos; Fowler, Scott W; Appleby, Peter

    2003-05-20

    Sediment cores from a hydrothermal vent zone off Milos Island in the Aegean Sea were dated using the 210Pb method. The average unsupported 210Pb inventory in the cores was calculated to be 3256 Bq m(-2). The corresponding mean annual 210Pb flux of 105 Bq m(-2) year(-1) is comparable to estimates of the atmospheric flux given in the literature. 210Pb fluxes calculated from the unsupported 210Pb inventories in cores are also comparable with the 210Pb vertical fluxes determined from settling particles off the coast of Milos Island. The highest unsupported 210Pb concentrations (89 Bq kg(-1)) were measured in the sediments nearest to the hydrothermal vent area suggesting that the sedimentation rate is lowest at this site. Direct gamma measurements of 210Pb were used to date three sediment cores that are located at different distances from the vent zone: one is in the immediate vicinity of the vent; and others are outside the zone. Sedimentation rates for these cores, calculated using the CRS and CIC models, ranged from 0.088+/-0.008 cm year(-1) to 0.14+/-0.01 cm year(-1). Where both models were applicable, the results given by the two methods were in good agreement. 137Cs concentrations in all three cores generally declined with depth but showed no clear signal of either the period of maximum fallout from weapons testing or the Chernobyl accident. 210Po activities were also measured and the maximum 210Po concentration was in the sediment surface layer (166 Bq kg(-1)).

  18. Distribution and diversity of sulfur-oxidizing Thiomicrospira spp. at a shallow-water hydrothermal vent in the Aegean Sea (Milos, Greece).

    PubMed

    Brinkhoff, T; Sievert, S M; Kuever, J; Muyzer, G

    1999-09-01

    A shallow-water hydrothermal vent system in the Aegean Sea close to the island of Milos (Greece) was chosen to study the diversity and distribution of the chemolithoautotrophic sulfur-oxidizing bacterium Thiomicrospira. Cell numbers in samples from different regions around a solitary vent decreased toward the center of the vent (horizontal distribution), as well as with depth (vertical distribution), corresponding to an increase in temperature (from ca. 25 to 60 degrees C) and a decrease in pH (from ca. pH 7 to 5). Thiomicrospira was one of the most abundant culturable sulfur oxidizers and was even dominant in one region. Phylogenetic analysis of Thiomicrospira spp. present in the highest most-probable-number (MPN) dilutions revealed that most of the obtained sequences grouped in two new closely related clusters within the Thiomicrospira branch. Two different new isolates, i.e., Milos-T1 and Milos-T2, were obtained from high-dilution (10(-5)) enrichments. Phylogenetic analysis indicated that isolate Milos-T1 is related to the recently described Thiomicrospira kuenenii and Hydrogenovibrio marinus, whereas isolate Milos-T2 grouped with the MPN sequences of cluster 2. The predominance of strain Milos-T2 was indicated by its identification in several environmental samples by hybridization analysis of denaturing gradient gel electrophoresis (DGGE) patterns and by sequencing of one of the corresponding bands, i.e., ML-1, from the DGGE gel. The results shown in this paper support earlier indications that Thiomicrospira species are important members of hydrothermal vent communities.

  19. Depositional environment, foraminifer content and ESR ages of Quaternary Gediz Delta Sediments (Eastern Aegean Sea, İzmir-Western Turkey)

    NASA Astrophysics Data System (ADS)

    Gökçe Benli, Ekin; Aydın, Hülya; İşintek, İsmail; Engin, Birol; Şengöçmen, Berna

    2016-04-01

    Sediments and fossil content of Gediz Delta (Eastern Aegean Sea - İzmir) were examined based on the drilling core samples of the YSK-C and SK-246 drilling. W-SW part of the Delta is represented by continental delta sediments up to 6 meters and shallow marine detritic sediments up to 35 meters in the YSK-C drilling. Continental part consists of an soiled, graveled, muddy and sandy sediment in terms of rich organic substance. As for marine part, it consists of bioclast, muddy, fine graveled sand and by repetition of pebble, sand and bioclast bearing mud layers. Bioclasts comprise of bivalvia, echinoid, ostracod, gastropod, foramifer and bryozoa fragments. Benthic foraminiferal fauna determinated in the marine levels are represented by 55 bethic, 2 planktonic species. These foraminifers and bioclasts reflect that the W-SW part of the delta, has been occured in marine conditions between 8-31m deep. E-NE part of the delta is generally represented by continental sediments up to 43.5m in SK-246 drilling. In addition, it includes marine levels in 18-19 m, 23-24 m and 36-37,5 m intervals. Continental sediments of E-NE part is generally represented by calcareous and sandy mud rocks which mostly includes ash, tuff, and pebble derived from Neogene volcanic rocks. As for marine levels, it is composed of calcareous mud stones and calcareous clay stones including very thin gastropod, bivalvia and ostracod in 18- 19 and 36-37.5 meters whereas it is represented by sandy mud stones including a great deal of bentic foraminifer, bivalvia, bryozoa, echinoid, gastropod in 23-24 metres. Thus show that E-NE part of the delta is usually in continental condition but it is occasionally covered by sea. In aging studies of YSK-C core done by ESR method, age of 8-9 m interval is determined to be 11. 376 ± 0,067 Ka; however ages of 10-11m and 24-25 m intervals are revealed to be 16.466 ± 0,016 Ka and 15.344 ± 0,021 Ka respectively; finally age of 25-26 m interval is found to be 19.995 ± 0

  20. Tracing metal pollution sources of plants and soils in Güzelhisar Basin of Aegean Region, Turkey

    NASA Astrophysics Data System (ADS)

    Czarnecki, Sezin; Görsch, Carolin; Colak Esetlili, Bihter; Esetlili, Tolga; Tepecik, Mahmut; Kurucu, Yusuf; Anac, Dilek; Düring, Rolf-Alexander

    2016-04-01

    The study area Güzelhisar Basin is 6 km far from the city Aliaga, Aegean Region in the west part of Turkey which represents a rather industrialized area having five large iron and steel mills, but also areas of agriculture. A grid system of 2.5 km to the east and 2.5 km to the west of the Güzelhisar Stream was studied. The area was grouped into three main areas as West, Middle, and East region. Every 500 meters soil samples were taken after the rainfall (April-May) in 2014 from the GPS determined points at 0-30 and 30-60 cm depth. Soil reaction of the study area was determined within the range from 5.87 to 6.61. Even though, the West and the Middle regions had weak carbonate concentrations, the East region was poor in carbonates and relatively high electrical conductivity was measured. Topsoil contamination was examined by all investigated elements with the exception of Cd. An increase in pseudo total metal contents of Cr, Cu, Mn, Ni, and Zn was observed with the increasing distance from the coast with a simultaneous decrease in pH. Moreover, high plant metal concentrations [mg kg-¹, ± sd] were detected for B [20.7 ± 23.9], Cu [7.99 ± 5.17], Mn (79.3 ± 89.2), Ni (3.50 ± 3.48), and Zn (25.5 ± 20.1). Transfer of the elements from soil to plants increased in the following order: Co < As < Cr < Pb < Mn < Ni < Cu < Zn < Cd << B.

  1. Suspended particulate matter estimates using optical and acoustic sensors: application in Nestos River plume (Thracian Sea, North Aegean Sea).

    PubMed

    Anastasiou, Sotiria; Sylaios, Georgios K; Tsihrintzis, Vassilios A

    2015-06-01

    The present study investigates the use of combined methods of optical and acoustic sensors, in collaboration with direct in situ measurements, for the calibration and validation of a model transforming acoustic backscatter intensity series into suspended particulate matter (SPM) concentration datasets. The model follows previously elaborated techniques, placing particular attention to the parameterization of the acoustic absorption index as a function of water physical properties. Results were obtained from the annual deployment (during 2007-2008) of an upward-facing acoustic Doppler current profiler (ADCP) (307 kHz), equipped with a Wave Array, and an optical backscatter sensor (OBS), at the bottom of Thassos Passage near Nestos River plume (Thracian Sea, Northern Greece). The OBS was calibrated through linear regression, using 2007 and 2012 field sampling data, exhibiting an error of 13-14 % due to chlorophyll presence. The ADCP signal was calibrated through simultaneous measurements of backscatter intensity and turbidity profiles. Harmonic analysis on the model-produced SPM concentrations explained the tidal influence on their variability, especially during the summer. Empirical orthogonal functions analysis revealed the impact of waves and wave-induced currents on SPM variability. Finally, Nestos River sediment load was found uncorrelated to the SPM change in Thassos Passage, due to the dispersal and sediment deposition near the river mouth.

  2. Investigation of heavy metal pollution in eastern Aegean Sea coastal waters by using Cystoseira barbata, Patella caerulea, and Liza aurata as biological indicators.

    PubMed

    Aydın-Önen, S; Öztürk, M

    2017-01-19

    In order to have an extensive contamination profile of heavy metal levels (Cd, Cu, Fe, Mn, Ni, Pb, and Zn), seawater, sediment, Patella caerulea, Cystoseira barbata, and Liza aurata were investigated by using inductively coupled plasma-atomic emission spectrometry (ICP-AES). Samples were collected from five coastal stations along the eastern Aegean Sea coast (Turkey) on a monthly basis from July 2002 through May 2003. According to the results of this study, heavy metal levels were arranged in the following sequence: Fe > Pb > Zn > Mn > Ni > Cu > Cd for water, Fe > Cu > Mn > Ni > Zn > Pb > Cd for sediment, Fe > Zn > Mn > Pb > Ni > Cd > Cu for C. barbata, Fe > Zn > Mn > Ni > Pb > Cu > Cd for P. caerulea, and Fe > Zn > Mn > Cu > Ni > Pb > Cd for L. aurata. Moreover, positive relationships between Fe in water and Mn in water, Fe in sediment and Mn in sediment, Fe in C. barbata and Mn in C. barbata, Fe in P. caerulea and Mn in P. caerulea, and Fe in L. aurata and Mn in L. aurata may suggest that these metals could be originated from the same anthropogenic source. C. barbata represented with higher bioconcentration factor (BCF) values, especially for Fe, Mn, and Zn values. This observation may support that C. barbata can be used as an indicator species for the determinations of Fe, Mn, and Zn levels. Regarding Turkish Food Codex Regulation's residue limits, metal values in L. aurata were found to be lower than the maximum permissible levels issued by Turkish legislation and also the recommended limits set by FAO/WHO guidelines. The results of the investigation indicated that P. caerulea, L. aurata, and especially C. barbata are quantitative water-quality bioindicators and biomonitoring subjects for biologically available metal accumulation for Aegean Sea coastal waters.

  3. Eastern-Mediterranean ventilation variability during sapropel S1 formation, evaluated at two sites influenced by deep-water formation from Adriatic and Aegean Seas

    NASA Astrophysics Data System (ADS)

    Filippidi, A.; Triantaphyllou, M. V.; De Lange, G. J.

    2016-07-01

    Present-day bottom-water ventilation in the Eastern Mediterranean basin occurs through deep-water convection originating from the two marginal basins, i.e. Adriatic and Aegean Seas. In the paleo record, long periods of enhanced deep-water formation have been alternating with shorter periods of reduced deep-water formation. The latter is related mainly to low-latitude humid climate conditions and the enhanced deposition and preservation of organic-rich sediment units (sapropels). This study focuses on sedimentary archives of the most-recent sapropel S1, retrieved from two sites under the direct influence of the two deep-water formation areas. Restricted oxygen conditions have developed rapidly at the beginning of S1 deposition in the Adriatic site, but bottom-water conditions have not persistently remained anoxic during the full interval of sapropel deposition. In fact, the variability in intensity and persistence of sedimentary redox conditions at the two deep-water formation sites is shown to be related to brief episodes of climate cooling. In the Adriatic site, sapropel deposition appears to have been interrupted twice. The 8.2 ka event, only recovered at the Adria site, is characterized by gradually increasing suboxic to possibly intermittently oxic conditions and decreasing Corg fluxes, followed by an abrupt re-establishment of anoxic conditions. Another important event that disrupted sapropel S1 formation, has taken place at ca. 7.4 cal ka BP. The latter event has been recovered at both sites. In the Adriatic site it is followed by a period of sedimentary conditions that gradually change from suboxic to more permanently oxic, as deduced from the Mn/Al pattern. Using the same proxy for suboxic/oxic sedimentary redox conditions, we observe that conditions in the Aegean Sea site shift to more permanently oxic from the 7.4 ka event onwards. However, at both sites the accumulation and preservation of enhanced amounts of organic matter have continued under these

  4. New constraints on the active tectonic deformation of the Aegean

    USGS Publications Warehouse

    Nyst, M.; Thatcher, W.

    2004-01-01

    Site velocities from six separate Global Positioning System (GPS) networks comprising 374 stations have been referred to a single common Eurasia-fixed reference frame to map the velocity distribution over the entire Aegean. We use the GPS velocity field to identify deforming regions, rigid elements, and potential microplate boundaries, and build upon previous work by others to initially specify rigid elements in central Greece, the South Aegean, Anatolia, and the Sea of Marmara. We apply an iterative approach, tentatively defining microplate boundaries, determining best fit rigid rotations, examining misfit patterns, and revising the boundaries to achieve a better match between model and data. Short-term seismic cycle effects are minor contaminants of the data that we remove when necessary to isolate the long-term kinematics. We find that present day Aegean deformation is due to the relative motions of four microplates and straining in several isolated zones internal to them. The RMS misfit of model to data is about 2-sigma, very good when compared to the typical match between coseismic fault models and GPS data. The simplicity of the microplate description of the deformation and its good fit to the GPS data are surprising and were not anticipated by previous work, which had suggested either many rigid elements or broad deforming zones that comprise much of the Aegean region. The isolated deforming zones are also unexpected and cannot be explained by the kinematics of the microplate motions. Strain rates within internally deforming zones are extensional and range from 30 to 50 nanostrain/year (nstrain/year, 10-9/year), 1 to 2 orders of magnitude lower than rates observed across the major microplate boundaries. Lower strain rates may exist elsewhere withi the microplates but are only resolved in Anatolia, where extension of 13 ?? 4 nstrain/ year is required by the data. Our results suggest that despite the detailed complexity of active continental deformation

  5. Geochemistry of mylonitic gneisses from the Cycladic Basement Unit (Paros and Serifos, Aegean Sea): implications for protoliths of the high-grade gneisses

    NASA Astrophysics Data System (ADS)

    McGrath, Annette; Stouraiti, Christina; Windley, Brian

    2016-10-01

    The nature of the protolith(s) of high-grade gneisses from the Aegean Cycladic Basement Unit of the islands of Paros and Serifos is investigated using whole-rock geochemistry and Sr-Nd-O isotopes, in order to better understand their origin and to compare with possible equivalents from the southern Aegean region. On Paros, the basement unit consists of heterogeneous, mylonitized upper amphibolite-grade paragneisses and associated migmatitic rocks, whereas on Serifos, it consists of a mylonitized felsic gneiss, intercalated with layers and lenses of S-type leucogranites and minor mafic metavolcanics. New Nd, Sr and O isotope data suggest a predominantly crustal-derived source in the gneiss protolith from both islands: high initial 87Sr/86Sr ratios (≥7052 to 0.711, calculated at 300 Ma), negative initial ɛNd (-2.8 to -7.7) values for bulk-rock gneiss samples, and high δ18O values of quartz separates (+10 to +12.7 ‰). Major and trace-element variations corroborate that chemical differentiation within the NW Paros gneiss subunit results from progressive migmatitization. Peraluminous gneisses from eastern Paros share clear similarities with metapelitic gneisses from the Naxos gneiss dome, in terms of their trace-element patterns, ɛNd (300) and O isotope characteristics. The mineral assemblage, the fine grain size (due to intense mylonitization), and the metaluminous affinity of the South Serifos grey quartzofeldpathic gneiss do not allow for an unambiguous interpretation for these undated rocks; however, a combination of geochemical parameters and tectonic discrimination diagrams indicates an immature siliciclastic (greywacke) protolith from a continental island arc setting. Sr-Nd isotopic systematics indicates an increasing lower crustal component in gneisses from NW Paros, which is closer to the migmatitic core of the Paros dome. The overall isotopic trend of the gneissic Cycladic Basement Unit on Paros is spatially correlated with that of the Naxos gneiss dome.

  6. Long-term monitoring of the impact of a capture-based bluefin tuna aquaculture on water column nutrient levels in the Eastern Aegean Sea, Turkey.

    PubMed

    Aksu, Mehmet; Kaymakçi-Başaran, Asli; Egemen, Ozdemir

    2010-12-01

    Capture-based aquaculture of Atlantic bluefin tuna in the Mediterranean has been expanding rapidly but little is known about its environmental impact. In order to understand the consequences of this new sector, long-term monitoring is needed. For this purpose, we investigated the impact of a capture-based tuna farm located in the Gerence Bay (Aegean Sea) on the water column on a seasonal basis from 2005 to 2008, where in the water column, temperature, salinity, pH, dissolved oxygen, nutrients (nitrite, nitrate, ammonium, and phosphate), and chlorophyll a, in the sediment organic carbon variables were measured. Although highest nutrient concentrations were observed at the cage station as compared to the two controls in the production period, differences were not statistically significant between stations. Monitoring of physico-chemical parameters, nutrients, and chlorophyll a in water column together with organic carbon in sediment did not show detectable impact of fattening of Atlantic bluefin tuna. This was probably caused by strong currents present in the area, location of the cages away from the coast, hence high water depth, controlled feeding, and periodic presence of tuna farming activity in the study area.

  7. Molecular Basis of β-Thalassemia in the Population of the Aegean Region of Turkey: Identification of A Novel Deletion Mutation.

    PubMed

    Ozkinay, Ferda; Onay, Huseyin; Karaca, Emin; Arslan, Esra; Erturk, Biray; Ece Solmaz, Asli; Tekin, Ismihan Merve; Cogulu, Ozgur; Aydinok, Yeşim; Vergin, Canan

    2015-01-01

    β-Thalassemia (β-thal) is the most common monogenic disorder in Turkey. The aim of this study was to investigate the spectrum of β-thal mutations in the Aegean region of Turkey. The data was derived from 1171 unrelated β-thal subjects, detected in a regional reference hospital between November 2004 and December 2013. Screening for the 22 common mutations was performed using the polymerase chain reaction (PCR)-reverse dot-blot method, and direct automated DNA sequencing for the unknown samples. Thirty-one different β-thal alleles were identified. Seven mutations, namely IVS-I-110 (G > A) (41.7%), IVS-I-1 (G > A) (8.9%), IVS-II-745 (C > G) (8.6%), codon 8 (-AA) (7.7%), IVS-II-1 (G > A) (7.2%), IVS-I-6 (T > C) (6.6%), codon 39 (C > T) (4.6%) accounted for 85.3% of the mutated alleles. Frequencies of the remaining 24 β-thal mutations were less than 2.2%; these included one novel mutation [HBB: c.206_212del (p.Leu69Profs*19)], and four others [-56 (G > C), codon 16 (-C), IVS-I (-3) (C > T) (codon 29), codon 76 (-C)] found in Turkey for the first time. The results will help to prevent severe β-thal through genetic counseling and prenatal diagnosis (PND) in the Aegean region of Turkey.

  8. The seasonal cycles of stratification and circulation in the Thermaikos Gulf Region Of Freshwater Influence (ROFI), north-west Aegean

    NASA Astrophysics Data System (ADS)

    Hyder, P.; Simpson, J. H.; Christopoulos, S.; Krestenitis, Y.

    2002-11-01

    The Thermaikos Gulf is a shallow basin in the north-west Aegean. Communication with the open Aegean is restricted by the long (170 km), narrow (˜50 km) nature of the Gulf and the weak tidal flows. In consequence, the northern section of the Gulf experiences severe water quality problems arising from the untreated sewage from the city of Thessaloniki (population 1.1 million), pollutant discharges from industry around the Gulf, and nutrient input from three rivers, which flow in near the head of the Gulf. New observations over a 16-month period during 1994-95 indicate distinct winter and summer circulation regimes. In winter (December-April), strong freshwater input (˜350 m 3/s) generates a thin (5 m), low salinity, surface layer which flows southward over much of the Gulf, above relatively homogeneous high-salinity waters that flow to the north. In the low-salinity layer, close to the river deltas, short pulses of extremely low-salinity water occur daily, principally as the result of releases from the Aliakmon hydro-electric power dam. Between October and February, a cold, dense water mass is observed in the deeper water of the eastern Gulf, which appears to originate in the shallow waters of central Saloniki Bay as the result of cooling during northerly gales. During winter it appears that buoyancy forcing from high run-off, in combination with persistent southward wind stress results in wind-enhanced estuarine exchange. In summer (July-September), the surface low-salinity layer is not well defined and is confined to the western Gulf in the vicinity of the river sources. Throughout the Gulf, a thicker (10-20 m) mixed layer with low salinity, warm waters overlies a strong pycnocline. A weak barotropic gyre is observed in the Gulf at this time. Monthly estimates of the total freshwater content of the northern Gulf indicate that this layer results in an accumulation of freshwater in the Gulf over the summer, when the local river input is at a minimum. It appears

  9. A new metamorphic map of Syros Island (Aegean Sea, Greece): implications for strain localization from prograde to retrograde path

    NASA Astrophysics Data System (ADS)

    Laurent, Valentin; Jolivet, Laurent; Roche, Vincent; Augier, Romain; Scaillet, Stéphane; Cardello, Luca

    2015-04-01

    The Aegean domain is located in the eastern part of the Mediterranean and has undergone a complex Alpine history that can be summarized in two successive episodes: (1) The formation of the Hellenides-Taurides belt due to the convergence between Eurasia and Africa; during this episode, a series of oceanic and continental nappes entered the subduction zone and were thrust on top of each other in a HP-LT metamorphic context. (2) From 35-30 Ma, an acceleration of slab retreat led to the collapse of the belt and the formation of large detachments. The island of Syros (Cycladic Blueschists belt) is worldwide known for the excellent preservation of HP-LT tectonic and metamorphic features associated with these processes, possibly providing one of the best places to study the deformation and metamorphic evolution of the subduction interface. Syros has recorded a complex deformation history during both the prograde and retrograde phase that resulted in the juxtaposition of two main units: (1) the Cycladic Blueschists Unit (CBU), and (2) the Vari unit cropping out in the SE of the island. Conflicting tectonic interpretations have been proposed to explain the evolution of the island, in part reflecting the lack of consensus about the detailed tectonic structure of the CBU. A new geological and metamorphic map of Syros is proposed to better characterize the different structures related to prograde and/or retrograde deformation stages. High-resolution field-mapping, combined with detailed structural-petrological observations, allows us to subdivide the CBU into three sub-units separated by major ductile shear zones. From top to bottom, these are: 1) the Kampos, 2) the Chroussa, and 3) the Posidonia units. Each of these units experienced similar peak eclogite-facies conditions (ca. 20 kbar - 550 °C), variably overprinted under blueschist- and greenschist-facies conditions across the nappe pile. New ductile structures have been discovered. Among those, a new large-scale top

  10. Tectono-stratigraphic evolution through successive extensional events of the Anydros Basin, hosting Kolumbo volcanic field at the Aegean Sea, Greece

    NASA Astrophysics Data System (ADS)

    Nomikou, P.; Hübscher, C.; Ruhnau, M.; Bejelou, K.

    2016-03-01

    The structural evolution of the South Aegean Sea is little explored due to the lack of marine seismic data. Our present day understanding is mainly based on some island outcrops and GPS measurements. In this study we discuss the rather incremental opening of the Anydros Basin in the Pliocene during six major tectonic pulses and the subsequent basin fill processes by interpreting seismic data and derived time isochore maps. Between the active pulses basin floor tilting persisted on a much lower rate. Seismic data illustrate the depositional processes in the emerging Anydros Basin. The observation of onlap fill strata, divergent reflection pattern, moat channels and contourite drifts imply that deposition was controlled by turbidity and contour currents as well as the tilting basin floor. The metamorphic Attico-Cycladic basement shows a rise that aligns along an NW-SE directed axis crossing Anydros island. This axis marks a structural change of the Santorini-Amorgos Ridge and thus represents a major structural boundary. Dip angles of NE-SW trending major faults, like the Santorini-Amorgos Fault, indicate normal faulting to be the superior mechanism forming the present horst and graben environment. Hence, the area is likely to be in a state of NW-SE directed extensional stresses forming the asymmetric graben structure of Anydros. Secondary fault clusters strike the same direction but show much steeper dip angles, possibly indicating strike-slip movement or resulting from deformational stresses along the hinge zones of the normal faults. The majority of the faults we discovered are located in the area of earthquake clusters, which is another indication of recent faulting. Ring faults around Kolumbo submarine volcano, result from caldera collapse and mark the diameter of the magma chamber approximately to 20 km.

  11. Geomorphological characteristics of the onshore/offshore volcanic edifices with respect to their evolutionary stage in the South Aegean Sea, Greece.

    NASA Astrophysics Data System (ADS)

    Carey, S.; Nomikou, P.; Papanikolaou, D.; Alexandri, M.

    2014-12-01

    Volcanism in the South Aegean Sea first occurred about 3-4 million years ago, along four different volcanic island groups, including both onshore and recently discovered offshore volcanoes: 1) Starting from the west, the Methana group consists of the Methana stratovolcano, composed exclusively of volcaniclastics and lavas, creating cones and domes onland and the Paphsanias submarine cone in the Epidavros tectonic graben, bordered by E-W normal faults. It has a 2 km basal diameter at 400 m depth and its top rises to 150 m. 2) The Milos-Antimilos group consists of volcanic domes and calderas onland and three submarine domes to the east of Antimilos. A hydrothermal vent field is limited in the SE coastal zone of Milos, 3) The Santorini group consists of: (i) the older volcanic cones of Christianna islets and three submarine domes east of them, (ii) Santorini volcano which during the last 500 ka experienced repeated caldera collapses following Plinian eruptions and edifice rebuilding, represented by the growth of the Kamenes islands after the last catastrophic Late Bronze age eruption. (iii) a chain of about twenty submarine volcanic domes and craters in the Kolumbo zone northeast of Santorini. Kolumbo volcano is a 3 km diameter cone with a 1500 m wide crater, a crater rim as shallow as 18 m depth and a flat crater floor at 505 m depth containing an active hydrothermal vent field degassing 99% of CO2. 4) The Kos-Nisyros group at the eastern edge of the Hellenic Volcanic arc, comprises several domes and craters offshore and Nisyros volcano consists exclusively of alternating lava and pyroclastic deposits following several phases of reconstruction and caldera collapse. The rhyodacitic domes of Profitis Ilias are the latest evolutionary stage of Nisyros volcano which disrupted a pre-existed caldera and may be regarded as an earlier reconstruction phase similar to the Kameni islands at Santorini. The volcanic relief reaches 1100-1200 m in most cases. This is produced from

  12. Normalization to lithium for the assessment of metal contamination in coastal sediment cores from the Aegean Sea, Greece.

    PubMed

    Aloupi, M; Angelidis, M O

    2001-07-01

    Sediment cores from the harbour and the coastal zone of Mytilene, island of Lesvos, Greece, were used to study the metal contamination caused by the discharge of untreated urban effluents into the sea. In the harbour. the upper layers were highly enriched in Cd, Cu, Pb and Zn, while no metal enrichment was recorded in the cores from the wider coastal zone. The metal data were normalized to Li (conservative element) to compensate for the natural textural and mineralogical variability. It was found that only the upper 18 cm of the core collected from the harbour of Mytilene could be reported as metal contaminated. Also, through the normalization procedure, it was found that the surface layers of coastal sediments assumed 'clean' were enriched in Pb, probably as a result of atmospheric transportation of the metal from the nearby town.

  13. Climatological Factors Affecting Electromagnetic Surface Ducting in the Aegean Sea Region

    DTIC Science & Technology

    2012-03-01

    19  x Figure 11.  The Azores or Bermuda High and southwest and south-central Asia thermal low tend to produce a...of Frequency (green lines with triangle markers), moisture mixing ratio at the surface level (blue lines with rhombus markers) and moisture mixing...of Frequency (green lines with triangle markers), moisture mixing ratio at the surface level (blue lines with rhombus markers) and moisture mixing

  14. Evaluation of sediment contamination by monoaromatic hydrocarbons in the coastal lagoons of Gulf of Saros, NE Aegean Sea.

    PubMed

    Ünlü, Selma; Alpar, Bedri

    2017-03-19

    The concentrations and distribution of monoaromatic hydrocarbons (benzene, toluene, ethyl benzene and the sum of m-, p- and o-, xylenes) were determined in the sediments of coastal lagoons of the Gulf of Saros, using a static headspace GC-MS. The total concentrations of BTEX compounds ranged from 368.5 to below detection limit 0.6μgkg(-1) dw, with a mean value of 61.5μgkg(-1) dw. The light aromatic fraction of m-, p-xylene was the most abundant compound (57.1% in average), and followed by toluene (38.1%)>ethylbenzene (4.1%)>o-xylene (2.5%)>benzene (1.1%). The factor analysis indicated that the levels and distribution of BTEX compounds depend on the type of contaminant source (mobile/point), absorbance of compounds in sediment, and mobility of benzene compound and degradation processes. Point sources are mainly related to agricultural facilities and port activities while the dispersion of compounds are related with their solubility, volatility and effect of sea/saline waters on lagoons.

  15. New boron isotopic evidence for sedimentary and magmatic fluid influence in the shallow hydrothermal vent system of Milos Island (Aegean Sea, Greece)

    NASA Astrophysics Data System (ADS)

    Wu, Shein-Fu; You, Chen-Feng; Lin, Yen-Po; Valsami-Jones, Eugenia; Baltatzis, Emmanuel

    2016-01-01

    Magmatic sources may contribute a significant amount of volatiles in geothermal springs; however, their role is poorly understood in submarine hydrothermal systems worldwide. In this study, new results of B and δ11B in 41 hydrothermal vent waters collected from the shallow hydrothermal system of Milos island in the Aegean Sea were combined with previously published data from other tectonic settings and laboratory experiments to quantify the effects of phase separation, fluid/sediment interaction and magmatic contribution. Two Cl-extreme solutions were identified, high-Cl waters (Cl as high as 2000 mM) and low-Cl waters (Cl < 80 mM). Both sets of waters were characterized by high B/Cl (~ 1.2-5.3 × 10- 3 mol/mol) and extremely low δ11B (1.4-6.3‰), except for the waters with Mg content of near the seawater value and δ11B = 10.3-17.4‰. These high-Cl waters with high B/Cl and low δ11B plot close to the vent waters in sediment-hosted hydrothermal system (i.e., Okinawa Trough) or fumarole condensates from on-land volcanoes, implying B addition from sediment or magmatic fluids plays an important role. This is in agreement with fluid/sediment interactions resulting in the observed B and δ11B, as well as previously reported Br/I/Cl ratios, supporting a scenario of slab-derived fluid addition with elevated B, 11B-rich, and low Br/Cl and I/Cl, which is derived from the dehydration of subducted-sediments. The slab fluid becomes subsequently mixed with the parent magma of Milos. The deep brine reservoir is partially affected by injections of magmatic fluid/gases during degassing. The results presented here are crucial for deciphering the evolution of the brine reservoirs involved in phase separation, fluid/sediment interaction and magmatic contribution in the deep reaction zone of the Milos hydrothermal system; they also have implications in the understanding of the formation of metallic vein mineralization.

  16. Tracing organic and inorganic pollution sources of agricultural crops and water resources in Güzelhisar Basin of the Aegean Region - Turkey

    NASA Astrophysics Data System (ADS)

    Czarnecki, Sezin; Colak Esetlili, Bihter; Esetlili, Tolga; Tepecik, Mahmut; Anac, Dilek; Düring, Rolf-Alexander

    2014-05-01

    The study area Güzelhisar Basin is 6 km far from the city Aliaga, Aegean Region in Turkey which represents a rather industrialized area having five large iron and steel factories, but also areas of agriculture. Steel industry in Aliaga is causing metal pollution. Around Güzelhisar Basin and nearby, the dominant crop fields are cotton, maize, vegetables, olive trees and vineyards. Güzelhisar stream and dam water is used for irrigation of the agricultural land. Due to contamination from metal industry in Aliaga, organic farming is not allowed in this region. Industrial activities in the region present a threat on sustainable agriculture. The region is a multi-impacted area in terms of several pollutant sources affecting soil and water quality. The overall objective of the project is to trace back plant nutrients (N, P, K, Ca, Mg, Na, Fe, Mn, Zn, Cu, and B), hazardous substances (i. e. persistent organic pollutants), radionuclides (40K, 232Th, 226Ra/238U), and metal contents (As, Cd, Cr, Co, Cu, Hg, Mn, Ni, Pb, and Zn) by examining the soils, agricultural crops and natural plants from Güzelhisar Basin and water and sediments from Güzelhisar stream and dam. Spatial distribution of pollution will be evaluated by regionalization methods. For this, an advanced analytical methodology will be applied which provides an understanding of sources and occurrence of the respective substances of concern. An innovative multi-tracer approach comprising organic and inorganic marker substances, will identify and quantitatively assess sources and their impact on water pollution and the pollutant pathways in this agricultural crop production system.

  17. Climate variability and socio-environmental changes in the northern Aegean (NE Mediterranean) during the last 1500 years

    NASA Astrophysics Data System (ADS)

    Gogou, Alexandra; Triantaphyllou, Maria; Xoplaki, Elena; Izdebski, Adam; Parinos, Constantine; Dimiza, Margarita; Bouloubassi, Ioanna; Luterbacher, Juerg; Kouli, Katerina; Martrat, Belen; Toreti, Andrea; Fleitmann, Dominik; Rousakis, Gregory; Kaberi, Helen; Athanasiou, Maria; Lykousis, Vasilios

    2016-04-01

    We provide new evidence on sea surface temperature (SST) variations and paleoceanographic/paleoenvironmental changes over the past 1500 years for the north Aegean Sea (NE Mediterranean). The reconstructions are based on multiproxy analyses, obtained from the high resolution (decadal to multi-decadal) marine record M2 retrieved from the Athos basin. Reconstructed SSTs show an increase from ca. 850 to 950 AD and from ca. 1100 to 1300 AD. A cooling phase of almost 1.5 °C is observed from ca. 1600 AD to 1700 AD. This seems to have been the starting point of a continuous SST warming trend until the end of the reconstructed period, interrupted by two prominent cooling events at 1832 ± 15 AD and 1995 ± 2 AD. Application of an adaptive Kernel smoothing suggests that the current warming in the reconstructed SSTs of the north Aegean might be unprecedented in the context of the past 1500 years. Internal variability in atmospheric/oceanic circulations systems as well as external forcing as solar radiation and volcanic activity could have affected temperature variations in the north Aegean Sea over the past 1500 years. The marked temperature drop of approximately ~2°C at 1832 ± 15 yr AD could be related to the 1809 ΑD 'unknown' and the 1815 AD Tambora volcanic eruptions. Paleoenvironmental proxy-indices of the M2 record show enhanced riverine/continental inputs in the northern Aegean after ca. 1450 AD. The palaeoclimatic evidence derived from M2 record is combined with a socio-environmental study of the history of the north Aegean region. We show that the cultivation of temperature-sensitive crops, i.e. walnut, vine and olive, co-occurred with stable and warmer temperatures, while its end coincided with a significant episode of cooler temperatures. Periods of agricultural growth in Macedonia coincide with periods of warmer and more stable SSTs, but further exploration is required in order to identify the causal links behind the observed phenomena. The Black Death likely

  18. Climate variability and socio-environmental changes in the northern Aegean (NE Mediterranean) during the last 1500 years

    NASA Astrophysics Data System (ADS)

    Gogou, Alexandra; Triantaphyllou, Maria; Xoplaki, Elena; Izdebski, Adam; Parinos, Constantine; Dimiza, Margarita; Bouloubassi, Ioanna; Luterbacher, Juerg; Kouli, Katerina; Martrat, Belen; Toreti, Andrea; Fleitmann, Dominik; Rousakis, Gregory; Kaberi, Helen; Athanasiou, Maria; Lykousis, Vasilios

    2016-03-01

    We provide new evidence on sea surface temperature (SST) variations and paleoceanographic/paleoenvironmental changes over the past 1500 years for the north Aegean Sea (NE Mediterranean). The reconstructions are based on multiproxy analyses, obtained from the high resolution (decadal to multi-decadal) marine record M2 retrieved from the Athos basin. Reconstructed SSTs show an increase from ca. 850 to 950 AD and from ca. 1100 to 1300 AD. A cooling phase of almost 1.5 °C is observed from ca. 1600 AD to 1700 AD. This seems to have been the starting point of a continuous SST warming trend until the end of the reconstructed period, interrupted by two prominent cooling events at 1832 ± 15 AD and 1995 ± 1 AD. Application of an adaptive Kernel smoothing suggests that the current warming in the reconstructed SSTs of the north Aegean might be unprecedented in the context of the past 1500 years. Internal variability in atmospheric/oceanic circulations systems as well as external forcing as solar radiation and volcanic activity could have affected temperature variations in the north Aegean Sea over the past 1500 years. The marked temperature drop of approximately ∼2 °C at 1832 ± 15 yr AD could be related to the 1809 ΑD 'unknown' and the 1815 AD Tambora volcanic eruptions. Paleoenvironmental proxy-indices of the M2 record show enhanced riverine/continental inputs in the northern Aegean after ca. 1450 AD. The paleoclimatic evidence derived from the M2 record is combined with a socio-environmental study of the history of the north Aegean region. We show that the cultivation of temperature-sensitive crops, i.e. walnut, vine and olive, co-occurred with stable and warmer temperatures, while its end coincided with a significant episode of cooler temperatures. Periods of agricultural growth in Macedonia coincide with periods of warmer and more stable SSTs, but further exploration is required in order to identify the causal links behind the observed phenomena. The Black Death

  19. Causes for contemporary regional sea level changes.

    PubMed

    Stammer, Detlef; Cazenave, Anny; Ponte, Rui M; Tamisiea, Mark E

    2013-01-01

    Regional sea level changes can deviate substantially from those of the global mean, can vary on a broad range of timescales, and in some regions can even lead to a reversal of long-term global mean sea level trends. The underlying causes are associated with dynamic variations in the ocean circulation as part of climate modes of variability and with an isostatic adjustment of Earth's crust to past and ongoing changes in polar ice masses and continental water storage. Relative to the coastline, sea level is also affected by processes such as earthquakes and anthropogenically induced subsidence. Present-day regional sea level changes appear to be caused primarily by natural climate variability. However, the imprint of anthropogenic effects on regional sea level-whether due to changes in the atmospheric forcing or to mass variations in the system-will grow with time as climate change progresses, and toward the end of the twenty-first century, regional sea level patterns will be a superposition of climate variability modes and natural and anthropogenically induced static sea level patterns. Attribution and predictions of ongoing and future sea level changes require an expanded and sustained climate observing system.

  20. Inferences of Integrated Lithospheric Strength from Plate-Scale Analyses of Deformation Observed in the Aegean-Anatolian Region and the Indian Ocean

    NASA Astrophysics Data System (ADS)

    Houseman, Gregory

    2016-04-01

    In the context of a comprehensive review of the rheology and strength of the lithosphere (Marine and Petroleum Geology, 2011, doi:10.1016/j.marpetgeo.2011.05.008), Evgene Burov described the difficulty of extrapolating rock deformation laws derived from laboratory experiments to the time and length scales that apply when the Earth's lithosphere is deformed. Not only does the extrapolation introduce a large uncertainty, but even the relative importance of different possible mechanisms of deformation may be uncertain. Even though lithospheric deformation has a strong conceptual and theoretical basis, it is therefore essential, as Burov argued, that deformation laws for the lithosphere must be calibrated by using observations of deformation that occurs on a lithospheric length scale and at geological strain rates. The influence of regionally varying factors like crustal thickness, geothermal gradient and tectonic environment may induce large variations in how rapidly the lithosphere may deform in response to an applied load, not least in the contrast from continent to ocean. Plates may be deformed by different loading mechanisms but, when deformation is distributed over a broad region, the strain-rate field may be approximately constant with depth and we may integrate the in-plane stress components across the thickness of the lithosphere to derive a depth-averaged constitutive law for the deformation. This approximation is the basis for the thin viscous sheet formulation of lithospheric deformation and, in combination with appropriate observations, it allows us to calibrate the integrated resistance to processes like regional extension or convergence. In this talk I will summarise what we learn about effective lithospheric rheology from two recent studies of the distribution and rates of diffuse deformation of the lithosphere in, firstly the Anatolian-Aegean region, and secondly the Central Indian Ocean. In the first case the distribution of deformation is consistent

  1. Wild fire effects on floristic diversity in three thermo-Mediterranean vegetation types in a small islet of eastern Aegean sea

    NASA Astrophysics Data System (ADS)

    Abraham, Eleni; Kyriazopoulos, Apostolos; Korakis, George; Parissi, Zoi; Chouvardas, Dimitrios

    2014-05-01

    Sclerophyllus scrub formations, the main vegetation type in many islands of the Aegean area, are characterized by their high biodiversity. Dominant shrub species of sclerophyllus formations are well adapted to dry season conditions by various anatomical and physiological mechanisms. As a result, their biomass acts as very flammable fine fuel, and consequently wild fires are very common in these ecosystems. Wildfire effects on vegetation and biodiversity in the Mediterranean basin have been studied and the results are diverse depending mainly on vegetation type and frequency of fire. The aim of this study was to evaluate the effects of wildfire on floristic diversity and species composition in three thermo-Mediterranean vegetation types 1) Sacropoterium spinosum phrygana, 2) low formations of Cistus creticus and 3) low formations of Cistus creticus in abandoned terraces. The research was conducted in Enoussa islet, which is located northeastern of Chios Island, in May 2013 (one year after the fire). Vegetation sampling was performed along five transects placed in recently burned and in adjacent unburned sites of each vegetation type. The plant cover and the floristic composition were measured, while diversity, evenness and dominance indices were determined for the vegetation data. Vegetation cover and the floristic diversity were significant lower and higher respectively in burned areas in comparison to the unburned. The woody species followed by the annual grasses and the annual forbs dominated in both burned and unburned areas. However, the woody species were significantly decreased in the burned areas in all vegetation types, while the annual grasses only in the burned areas of Sacropoterium spinosum phrygana and Cistus creticus in abandoned terraces. Inversely, the annual forbs significantly increased in the burned sites of Cistus creticus formations. The highest value of Morisita-Horn Index of similarity between burned and unburned sites (beta diversity) was

  2. Aegean tectonics, a record of slab-overriding plate interactions (Invited)

    NASA Astrophysics Data System (ADS)

    Jolivet, L.; Faccenna, C.; Huet, B.; Lecomte, E.; Labrousse, L.; Denèle, Y.; Le Pourhiet, L.; Lacombe, O.; Burov, E. B.; Meyer, B.; Suc, J.; Popescu, S.; Monié, P.; Philippon, M.; Gueydan, F.; Brun, J.; Paul, A.; Salaün, G.; Armijo, R.

    2010-12-01

    Two opposing visions of the Aegean backarc tectonics implicitly contain contrasting images of the rheological behaviour of the lihosphere, supported by different sets of observations. The propagation of the NAF and extension in the Corinth Rift suggest a strongly localising rheology whereas the formation of MCC in the Cyclades and the Rhodope suggests instead a more viscous behaviour. This paradox was the seminal question addressed by the ANR-EGEO programme (2007-2010) that leads to the following conclusions: (1) The exhumation of the Cycladic MCC’s is accommodated by the N-dipping North Cycladic Detachment System (NCDS) that partly reworks the Vardar suture and at the base by a series of thrusts, including the basal contact of the Cycladic Blueschists (CBS) over the Cycladic Basement (CB). The activity of LANF is due to the reactivation of pre-existing discontinuities such as thrusts or earlier detachments and much less to the interaction with granitic plutons. (2) Exhumation in the Cyclades has proceeded in two stages: (a) Eocene syn-orogenic exhumation within the subduction lower/upperplate interface while the post-orogenic Rhodope MCC formed further north, (b) Oligo-Miocene post-orogenic extension in an MCC mode coeval with syn-orogenic exhumation in Crete and the Peloponnese. (3) Both stages were associated with slab retreat, as early as the Eocene with an acceleration at 30-35 Ma. (4) The localisation of the presently active steeply-dipping normal faults on the southern margin of the Corinth Rift may have been preceded by a partial reworking of thrusts and syn-orogenic detachments by shallow-dipping decollements. (5) The localisation of the NAF in the Marmara Sea region and the Northern Aegean Sea is now accurately dated between 5.3 and 5 Ma Ma using the erosion and deposition surfaces that mark the Messinian salinity Crisis and nannofossils ages. (6) The formation of MCCs in the Cyclades resulted in the draining of the low viscosity lower crust from the

  3. Regional sea level change in the Thailand-Indonesia region

    NASA Astrophysics Data System (ADS)

    Fenoglio-Marc, L.; Becker, M. H.; Buchhaupt, C.

    2013-12-01

    It is expected that the regional sea level rise will strongly affect particular regions with direct impacts including submergence of coastal zones, rising water tables and salt intrusion into groundwaters. It can possibly also exacerbate other factors as floodings, associated to storms and hurricanes, as well as ground subsidence of anthropogenic nature. The Thailand-Vietnam-Indonesian region is one of those zones. On land, the Chao-Praya and Mekong Delta are fertile alluvial zones. The potential for sea level increases and extreme floodings due to global warming makes the Deltas a place where local, regional, and global environmental changes are converging. We investigate the relative roles of regional and global mechanisms resulting in multidecadal variations and inflections in the rate of sea level change. Altimetry and GRACE data are used to investigate the variation of land floodings. The land surface water extent is evaluated at 25 km sampling intervals over fifteen years (1993-2007) using a multisatellite methodology which captures the extent of episodic and seasonal inundations, wetlands, rivers, lakes, and irrigated agriculture, using passive and active (microwaves and visible observations. The regional sea level change is analysed during the period 1993-2012 using satellite altimetry, wind and ocean model data, tide gauge data and GPS. The rates of absolute eustatic sea level rise derived from satellite altimetry through 19-year long precise altimeter observations are in average higher than the global mean rate. Several tide gauge records indicate an even higher sea level rise relative to land. We show that the sea level change is closely linked to the ENSO mode of variability and strongly affected by changes in wind forcing and ocean circulation. We have determined the vertical crustal motion at a given tide gauge location by differencing the tide gauge sea level time-series with an equivalent time-series derived from satellite altimetry and by computing

  4. An integrated multi-parameter monitoring approach for the quantification and mitigation of the climate change impact on the coasts of Eastern Crete, S. Aegean Sea (Project AKTAIA)

    NASA Astrophysics Data System (ADS)

    Ghionis, George; Alexandrakis, George; Karditsa, Aikaterini; Sifnioti, Dafni; Vousdoukas, Michalis; Andreadis, Olympos; Petrakis, Stelios; Poulos, Serafim; Velegrakis, Adonis; Kampanis, Nikolaos; Lipakis, Michalis

    2014-05-01

    associated sediment transport and beach morphodynamics, calibrated with in situ data, is used to predict beach response and vulnerability to different climate change scenarios. Finally, the socio-economic impact of the climate change on the coastal zone will be assessed and a management protocol for the coastal zone and for the mitigation of the climate change impact will be developed. The ultimate scope of the project is to benefit the society by providing current and high quality information on the consequences of the climate change, especially those related to sea-level rise, and on the available protection and mitigation measures. In addition, the technological product will help in the proper planning of the required actions and technical interventions, reducing the need for costly, incomplete and frequently redundant localized studies and the risk of unsuccessful interventions. Acknowledgements The project is supported by the Action "Cooperation 2007-2013" (09SYN-31-711 "AKTAIA") of the Operational Program "Competitiveness and Entrepreneurship" co-funded by the European Regional Development Fund (ERDF) and the General Secretariat for Research and Technology (Hellenic Ministry of Education).

  5. Air-sea interactions in sea surface temperature frontal region

    NASA Astrophysics Data System (ADS)

    Pianezze, Joris; Redelsperger, Jean-Luc; Ardhuin, Fabrice; Reynaud, Thierry; Marié, Louis; Bouin, Marie-Noelle; Garnier, Valerie

    2015-04-01

    Representation of air-sea exchanges in coastal, regional and global models represent a challenge firstly due to the small scale of acting turbulent processes comparatively to the resolved scales of these models. Beyond this subgrid parameterization issue, a comprehensive understanding of air-sea interactions at the turbulent process scales is still lacking. Many successful efforts are dedicated to measure the energy and mass exchanges between atmosphere and ocean, including the effect of surface waves. In comparison less efforts are brought to understand the interactions between the atmospheric boundary layer and the oceanic mixing layer. In this regard, we are developing research mainly based on ideal and realistic numerical simulations which resolve very small scales (horizontal resolutions from 1 to 100 meters) in using grid nesting technics and coupled ocean-wave-atmosphere models. As a first step, the impact of marked gradients in sea surface temperatures (SST) on air-sea exchanges has been explored through realistic numerical simulations at 100m horizontal resolution. Results from simulations of a case observed during the FROMVAR experiment will be shown. The talk will mainly focus on the marked impact of SST front on the atmospheric boundary layer (stability and winds), the air-sea exchanges and surface parameters (rugosity, drag coefficient) Results will be also shown on the strong impact on the simulated atmosphere of small scale variability of SST field.

  6. Upper Limit for Regional Sea Level Projections

    NASA Astrophysics Data System (ADS)

    Jevrejeva, Svetlana; Jackson, Luke; Riva, Riccardo; Grinsted, Aslak; Moore, John

    2016-04-01

    With more than 150 million people living within 1 m of high tide future sea level rise is one of the most damaging aspects of warming climate. The latest Intergovernmental Panel on Climate Change report (AR5 IPCC) noted that a 0.5 m rise in mean sea level will result in a dramatic increase the frequency of high water extremes - by an order of magnitude, or more in some regions. Thus the flood threat to the rapidly growing urban populations and associated infrastructure in coastal areas are major concerns for society. Hence, impact assessment, risk management, adaptation strategy and long-term decision making in coastal areas depend on projections of mean sea level and crucially its low probability, high impact, upper range. With probabilistic approach we produce regional sea level projections taking into account large uncertainties associated with Greenland and Antarctica ice sheets contribution. We calculate the upper limit (as 95%) for regional sea level projections by 2100 with RCP8.5 scenario, suggesting that for the most coastlines upper limit will exceed the global upper limit of 1.8 m.

  7. Caribbean Sea Region Pyrrhocoroidea (Hemiptera: Pyrrhocoridae, Largidae).

    PubMed

    Schaefer, C W; Stehlík, J L

    2013-08-01

    A synopsis of the Pyrrhocoridae and Largidae (Pyrrhocoroidea) of the Caribbean Sea Region is given. Three new taxa are described: Dysdercus jamaicensis jindrai Stehlík n. subsp. (Dominican Republic); Largus fumosus fumosus Stehlík n. sp. (Panama-Barro Colorado Island); and Largus fumosus nigromembranaceus Stehlík n. subsp. (Panama). Largus pallidus Halstead is downgraded to a subspecies of Largus davisi Barber, i.e., L. davisi pallidus Halstead n. stat. The following new records are provided: Dysdercus (Dysdercus) andreae (Linnaeus) from Cayman Islands; Acinocoris elegans van Doesburg from Trinidad; Fibrenus pehlkei Schmidt and Largus maculatus Schmidt from Panama; and Largus obovatus (Barber) from Haiti. Altogether, we report 20 species and 3 subspecies of Pyrrhocoridae and 13 species and 2 subspecies of Largidae from the Caribbean Sea Region.

  8. Vertical diffusion and oxygen consumption during stagnation periods in the deep North Aegean

    NASA Astrophysics Data System (ADS)

    Zervakis, Vassilis; Krasakopoulou, Evangelia; Georgopoulos, Dimitris; Souvermezoglou, Ekaterini

    2003-01-01

    Ventilation of the deep basins of the North Aegean Sea takes place during relatively scarce events of massive dense water formation in that region. In the time intervals between such events, the bottom waters of each sub-basin are excluded from interaction with other water masses through advection or isopycnal mixing and the only process that changes their properties is diapycnal mixing with overlying waters. In this work we utilize a simple one-dimensional model in order to estimate the vertical eddy diffusion coefficient Kρ based on the observed rate of change of density and stratification. Vertical diffusivity is estimated for each of three sub-basins of the North Aegean, one of convex shape of the seabed and the other two of concave topography. It is noteworthy that the convex sub-basin exhibited much higher vertical diffusivity than the two concave sub-basins, a fact consistent with theoretical predictions that internal-wave-induced mixing is higher over the former shape of seabed. Furthermore, the estimates of Kρ are exploited in computing the vertical transport of dissolved oxygen through diffusion and the rate of oxygen consumption by decaying organic matter. The different levels of the estimated diffusion and oxygen consumption rates testify to the dynamical and biogeochemical characteristics of each basin.

  9. SeaWinds - Oceans, Land, Polar Regions

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The SeaWinds scatterometer on the QuikScat satellite makes global radar measurements -- day and night, in clear sky and through clouds. The radar data over the oceans provide scientists and weather forecasters with information on surface wind speed and direction. Scientists also use the radar measurements directly to learn about changes in vegetation and ice extent over land and polar regions.

    This false-color image is based entirely on SeaWinds measurements obtained over oceans, land, and polar regions. Over the ocean, colors indicate wind speed with orange as the fastest wind speeds and blue as the slowest. White streamlines indicate the wind direction. The ocean winds in this image were measured by SeaWinds on September 20, 1999. The large storm in the Atlantic off the coast of Florida is Hurricane Gert. Tropical storm Harvey is evident as a high wind region in the Gulf of Mexico, while farther west in the Pacific is tropical storm Hilary. An extensive storm is also present in the South Atlantic Ocean near Antarctica.

    The land image was made from four days of SeaWinds data with the aid of a resolution enhancement algorithm developed by Dr. David Long at Brigham Young University. The lightest green areas correspond to the highest radar backscatter. Note the bright Amazon and Congo rainforests compared to the dark Sahara desert. The Amazon River is visible as a dark line running horizontally though the bright South American rain forest. Cities appear as bright spots on the images, especially in the U.S. and Europe.

    The image of Greenland and the north polar ice cap was generated from data acquired by SeaWinds on a single day. In the polar region portion of the image, white corresponds to the largest radar return, while purple is the lowest. The variations in color in Greenland and the polar ice cap reveal information about the ice and snow conditions present.

    NASA's Earth Science Enterprise is a long-term research and technology program designed to

  10. Migration waves to the Baltic Sea region.

    PubMed

    Lappalainen, T; Laitinen, V; Salmela, E; Andersen, P; Huoponen, K; Savontaus, M-L; Lahermo, P

    2008-05-01

    In this study, the population history of the Baltic Sea region, known to be affected by a variety of migrations and genetic barriers, was analyzed using both mitochondrial DNA and Y-chromosomal data. Over 1200 samples from Finland, Sweden, Karelia, Estonia, Setoland, Latvia and Lithuania were genotyped for 18 Y-chromosomal biallelic polymorphisms and 9 STRs, in addition to analyzing 17 coding region polymorphisms and the HVS1 region from the mtDNA. It was shown that the populations surrounding the Baltic Sea are genetically similar, which suggests that it has been an important route not only for cultural transmission but also for population migration. However, many of the migrations affecting the area from Central Europe, the Volga-Ural region and from Slavic populations have had a quantitatively different impact on the populations, and, furthermore, the effects of genetic drift have increased the differences between populations especially in the north. The possible explanations for the high frequencies of several haplogroups with an origin in the Iberian refugia (H1, U5b, I1a) are also discussed.

  11. Mitochondrial control region variability in Mytilus galloprovincialis populations from the central-Eastern Mediterranean Sea.

    PubMed

    Giantsis, Ioannis A; Abatzopoulos, Theodore J; Angelidis, Panagiotis; Apostolidis, Apostolos P

    2014-06-30

    The variable domain 1 (VD1) domain of the control region and a small segment of the rrnaL gene of the F mtDNA type were sequenced and analyzed in 174 specimens of Mytilus galloprovincialis. Samples were collected from eight locations in four Central-Eastern (CE) Mediterranean countries (Italy, Croatia, Greece and Turkey). A new primer, specific for the F mtDNA type, was designed for the sequencing procedure. In total 40 different haplotypes were recorded, 24 of which were unique. Aside from the two populations situated in Thermaikos gulf (Northern Aegean, Greece), relatively high levels of haplotype and nucleotide diversity were estimated for both Central and Eastern Mediterranean populations. Eight out of the 40 haplotypes were shared by at least three populations while two of them were found in all populations. ΦST and cluster analysis revealed lack of structuring among CE Mediterranean populations with the exception of those located at the Sea of Marmara and Croatian coast which were highly differentiated. Apart from the species' inherit dispersal ability, anthropogenic activities, such as the repeated translocations of mussel spat, seem to have played an important role in shaping the current genetic population structure of CE M. galloprovincialis mussels.

  12. Mitochondrial Control Region Variability in Mytilus galloprovincialis Populations from the Central-Eastern Mediterranean Sea

    PubMed Central

    Giantsis, Ioannis A.; Abatzopoulos, Theodore J.; Angelidis, Panagiotis; Apostolidis, Apostolos P.

    2014-01-01

    The variable domain 1 (VD1) domain of the control region and a small segment of the rrnaL gene of the F mtDNA type were sequenced and analyzed in 174 specimens of Mytilus galloprovincialis. Samples were collected from eight locations in four Central-Eastern (CE) Mediterranean countries (Italy, Croatia, Greece and Turkey). A new primer, specific for the F mtDNA type, was designed for the sequencing procedure. In total 40 different haplotypes were recorded, 24 of which were unique. Aside from the two populations situated in Thermaikos gulf (Northern Aegean, Greece), relatively high levels of haplotype and nucleotide diversity were estimated for both Central and Eastern Mediterranean populations. Eight out of the 40 haplotypes were shared by at least three populations while two of them were found in all populations. ΦST and cluster analysis revealed lack of structuring among CE Mediterranean populations with the exception of those located at the Sea of Marmara and Croatian coast which were highly differentiated. Apart from the species’ inherit dispersal ability, anthropogenic activities, such as the repeated translocations of mussel spat, seem to have played an important role in shaping the current genetic population structure of CE M. galloprovincialis mussels. PMID:24983478

  13. Development of a cost-effective method for nitrate and nitrite determination in leafy plants and nitrate and nitrite contents of some green leafy vegetables grown in the Aegean region of Turkey.

    PubMed

    Ozdestan, Ozgül; Uren, Ali

    2010-05-12

    An accurate, fast, easily applicable, and cost-effective method for the determination of nitrate and nitrite was developed. This method was much more reliable than the cadmium column reduction method, which is a tedious and time-consuming procedure and not easily applicable. The principle of the method was reduction of nitrate to nitrite with cadmium acetate solution and zinc powder and then treatment with Griess reagent. Recovery of the method changed from 92.9 to 102.8%, and detection limit was found as 31.4 mg/kg. Coefficient of variation was 3.16% for intraday precision. Nitrate and nitrite contents of 10 types of leafy vegetables native to the Aegean region of Turkey were determined. Wild radish, chicory, fennel, blessed thistle, blue mallow, and chard were analyzed for the first time. Nitrate contents were found between 354.8 mg/kg for iceberg lettuce and 4653 mg/kg for wild radish. Tested vegetables contained <26.33 mg/kg nitrite.

  14. The Aegean in the Early 7th Millennium BC: Maritime Networks and Colonization.

    PubMed

    Horejs, B; Milić, B; Ostmann, F; Thanheiser, U; Weninger, B; Galik, A

    The process of Near Eastern neolithization and its westward expansion from the core zone in the Levant and upper Mesopotamia has been broadly discussed in recent decades, and many models have been developed to describe the spread of early farming in terms of its timing, structure, geography and sociocultural impact. Until now, based on recent intensive investigations in northwestern and western Anatolia, the discussion has mainly centred on the importance of Anatolian inland routes for the westward spread of neolithization. This contribution focuses on the potential impact of east Mediterranean and Aegean maritime networks on the spread of the Neolithic lifestyle to the western edge of the Anatolian subcontinent in the earliest phases of sedentism. Employing the longue durée model and the concept of 'social memory', we will discuss the arrival of new groups via established maritime routes. The existence of maritime networks prior to the spread of farming is already indicated by the high mobility of Epipalaeolithic/Mesolithic groups exploring the Aegean and east Mediterranean seas, and reaching, for example, the Cyclades and Cyprus. Successful navigation by these early mobile groups across the open sea is attested by the distribution of Melian obsidian. The potential existence of an additional Pre-Pottery Neolithic (PPN) obsidian network that operated between Cappadocia/Cilicia and Cyprus further hints at the importance of maritime coastal trade. Since both the coastal and the high seas networks were apparently already well established in this early period, we may further assume appropriate knowledge of geographic routes, navigational technology and other aspects of successful seafaring. This Mesolithic/PPN maritime know-how package appears to have been used by later groups, in the early 7th millennium calBC, exploring the centre of the Anatolian Aegean coast, and in time establishing some of the first permanent settlements in that region. In the present paper, we

  15. Meiofauna, microflora and geochemical properties of the late quaternary (Holocene) core sediments in the Gulf of Izmir (Eastern Aegean Sea, Turkey)

    NASA Astrophysics Data System (ADS)

    Yümün, Zeki Ü.; Meriç, Engin; Avşar, Niyazi; Nazik, Atike; Barut, İpek F.; Yokeş, Baki; Sagular, Enis K.; Yildiz, Ayşegül; Eryilmaz, Mustafa; Kam, Erol; Başsari, Asiye; Sonuvar, Bora; Dinçer, Feyza; Baykal, Kubilay; Kaya, Seyhan

    2016-12-01

    The Gulf of Izmir has seen the construction of marinas at four locations; Karşıyaka, Bayraklı, İnciraltı and Urla (Çeşmealtı). Six drilling holes have been structured for each location. Morphological abnormities observed in foraminifer tests, obtained from these core drillings, and coloring encountered in both foraminifer tests and ostracod carapeces, provide evidence of natural and unnatural environmental pollution. The objectives of this study are to identify micro and macro fauna, foraminifers in particular, contained within sediments in the above-mentioned locations; to investigate the background of pollution in the Gulf Region; and to determine pollution's impact upon benthic foraminifer and ostracods. Çeşmealtı foraminifera tests did not lead to color and morphological changes. But foraminifera tests samples collected from Karşıyaka, Bayraklı and İnciraltı led them to turn black (Plate 4-6). However, concentrations of heavy metals (Ni, Cr and Mn) obtained from the sediments of Karşıyaka, Bayraklı and İnciraltı locations are higher than those obtained from the Çeşmealtı samples and high concentrations of these elements may be the cause of the color change in the samples during the foraminifera tests. In Karşıyaka and Bayraklı ostracod samples, Bosquetina carinella, Pterygocythereis jonesi, Semicytherura species; in the Çeşmealtı/Urla zone, Cyprideis torosa; in İnciraltı, Pseudopsammocythere reniformis; and in four zones, Loxoconcha and Xestoleberis species were observed in the range of relative frequency. The same analyses were done on nannoplankton but they did not lead to color and morphological changes.

  16. Tectonics of the Red Sea region reassessed

    NASA Astrophysics Data System (ADS)

    Ghebreab, Woldai

    1998-11-01

    The brittle upper level of the continental crust had been rifted with or without ocean opening many times in many places during the geological past and the process is still happening. Since the advent of plate tectonic theory in the early 1960s, the formation of such rifts has been viewed in the context of plate tectonic processes that caused the repeated dispersal of supercontinents. Several researchers focused on the mechanisms of formation of continental rifts because some rifts, like the Red Sea and Gulf of Aden, are precursors to ocean basins and many hydrocarbons yet to be located which are either directly or indirectly related to rift structures. The East African Rift System and the Red Sea-Gulf of Aden young oceans have been considered as prime examples of the early stage of continental separation that has long been a testing ground for classical hypotheses of continental drift. The Red Sea separates the once contiguous Neoproterozoic Arabian-Nubian Shields and started opening about 25 Ma ago. Geophysics and geochronology of dredged basaltic rocks indicate that sea-floor spreading began at only about 4-5 Ma. Numerous multidisciplinary investigations have been carried out in this region. However, several questions remain unresolved. Examples pertain to the nature of the crust that underlies the shelves, the extent of the ocean floor, the interplay between sea-floor spreading, crustal extension and plutonic activity and mechanisms of rifting. Several mechanisms of rifting have been proposed for the formation of the Red Sea. Examples include extension by prolonged steep normal faulting (horst-graben terrain), early diffuse ductile extension followed by brittle deformation, low-angle lithospheric simple shear, low-angle shear and magmatic expansion, lithospheric thinning by faulting and dike injection, northeastward migration of asymmetric rifting over a fixed mantle plume and the formation of pull-apart basin(s) by transtension. The major differences between

  17. Variscan orogeny in the Black Sea region

    NASA Astrophysics Data System (ADS)

    Okay, Aral I.; Topuz, Gültekin

    2017-03-01

    Two Gondwana-derived Paleozoic belts rim the Archean/Paleoproterozoic nucleus of the East European Platform in the Black Sea region. In the north is a belt of Paleozoic passive-margin-type sedimentary rocks, which extends from Moesia to the Istanbul Zone and to parts of the Scythian Platform (the MOIS Block). This belt constituted the south-facing continental margin of the Laurussia during the Late Paleozoic. This margin was deformed during the Carboniferous by folding and thrusting and forms the Variscan foreland. In the south is a belt of metamorphic and granitic rocks, which extends from the Balkanides through Strandja, Sakarya to the Caucasus (BASSAC Block). The protoliths of the metamorphic rocks are predominantly late Neoproterozoic granites and Paleozoic sedimentary and igneous rocks, which were deformed and metamorphosed during the Early Carboniferous. There are also minor eclogites and serpentinites, mostly confined to the northern margin of the BASSAC Block. Typical metamorphism is of low pressure-high temperature type and occurred during the Early Carboniferous (Visean, 340-330 Ma) coevally with that observed in the Central Europe. Volumetrically, more than half of the crystalline belt is made up of Carboniferous-earliest Permian (335-294 Ma) granites. The type of metamorphism, its concurrent nature over 1800 km length of the BASSAC Block and voluminous acidic magmatism suggest that the thermal event probably occurred in the deep levels of a continental magmatic arc. The BASSAC arc collided with Laurussia in the mid-Carboniferous leading to the foreland deformation. The ensuing uplift in the Permian resulted in the deposition of continental red beds, which are associated with acidic magmatic rocks observed over the foreland as well as over the BASSAC Block. In the Black Sea region, there was no terminal collision of Laurussia with Gondwana during the Late Paleozoic and the Laurussia margin continued to face the Paleo-Tethyan ocean in the south.

  18. Variscan orogeny in the Black Sea region

    NASA Astrophysics Data System (ADS)

    Okay, Aral I.; Topuz, Gültekin

    2016-09-01

    Two Gondwana-derived Paleozoic belts rim the Archean/Paleoproterozoic nucleus of the East European Platform in the Black Sea region. In the north is a belt of Paleozoic passive-margin-type sedimentary rocks, which extends from Moesia to the Istanbul Zone and to parts of the Scythian Platform (the MOIS Block). This belt constituted the south-facing continental margin of the Laurussia during the Late Paleozoic. This margin was deformed during the Carboniferous by folding and thrusting and forms the Variscan foreland. In the south is a belt of metamorphic and granitic rocks, which extends from the Balkanides through Strandja, Sakarya to the Caucasus (BASSAC Block). The protoliths of the metamorphic rocks are predominantly late Neoproterozoic granites and Paleozoic sedimentary and igneous rocks, which were deformed and metamorphosed during the Early Carboniferous. There are also minor eclogites and serpentinites, mostly confined to the northern margin of the BASSAC Block. Typical metamorphism is of low pressure-high temperature type and occurred during the Early Carboniferous (Visean, 340-330 Ma) coevally with that observed in the Central Europe. Volumetrically, more than half of the crystalline belt is made up of Carboniferous-earliest Permian (335-294 Ma) granites. The type of metamorphism, its concurrent nature over 1800 km length of the BASSAC Block and voluminous acidic magmatism suggest that the thermal event probably occurred in the deep levels of a continental magmatic arc. The BASSAC arc collided with Laurussia in the mid-Carboniferous leading to the foreland deformation. The ensuing uplift in the Permian resulted in the deposition of continental red beds, which are associated with acidic magmatic rocks observed over the foreland as well as over the BASSAC Block. In the Black Sea region, there was no terminal collision of Laurussia with Gondwana during the Late Paleozoic and the Laurussia margin continued to face the Paleo-Tethyan ocean in the south.

  19. Geodynamic Evolution of the Banda Sea Region

    NASA Astrophysics Data System (ADS)

    Kaymakci, N.; Decker, J.; Orange, D.; Teas, P.; Van Heiningen, P.

    2013-12-01

    We've carried out a large on- and offshore study in Eastern Indonesia to characterize the major structures and to provide constraints on the Neogene geodynamic evolution of the Banda Sea region. The onshore portion utilized remote sensing data and published geology. We tied the onshore to the offshore using recently acquired high resolution bathymetric data (16m and 25m bin size) and 2D seismic profiles that extend from Sulawesi in the west to Irian Jaya in the east across the northern part of the Banda Arc. We interpret the northern boundary of the 'Birds Head' (BH) of Papua, the Sorong Fault, to be a sinistral strike-slip fault zone with a minimum of 48 km displacement over the last few million years. The western boundary fault of Cendrawasih Basin defines the eastern boundary of BH and corresponds to the Wandamen Peninsula which comprises high pressure metamorphic rocks, including eclogite and granulite facies rocks, with exhumation ages from 4 to 1 Ma. Earthquake focal mechanism solutions indicate that the eastern boundary of BH is linked with a large scale offshore normal fault which we suggest may be related to the exhumation of the Wandamen Peninsula. The eastern boundary of Cendrawasih Basin is defined by a large transpressive belt along which BH is decoupled from the rest of Papua / Irian Jaya. This interpretation is supported by recent GPS studies. We propose that the BH and the Pacific plate are coupled, and therefore the Birds Head is therefore completely detached from Irian Jaya. Furthermore, Aru Basin, located at the NE corner of Banda Arc, is a Fault-Fault-Transform (FFT) type triple junction. According to available literature information the Banda Sea includes three distinct basins with different geologic histories; the North Banda Sea Basin (NBSB) was opened during 12-7 Ma, Wetar-Damar Basin (WDB) during 7-3.5 Ma and Weber Basin (WB) 3-0 Ma. Our bathymetric and seismic data indicated that the NBSB and Weber Basin lack normal oceanic crust and are

  20. On the Impacts of Different Surface Forcing Regimes for Deep Water Formation in the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Josey, S.; Tsimplis, M.; Gomis, D.; Ruiz, S.; Marcos, M.; Somot, S.

    2009-04-01

    Deep water formation is known to occur at 3 major sites (the Gulf of Lions, Adriatic and Aegean Seas) in the Mediterranean basin. However, the role played by air-sea interaction in setting the frequency and strength of formation events (including major transient episodes such as that experienced in the Aegean sea in the early 1990s) is not well understood. We will explore this relationship using air-sea heat, freshwater and density flux fields, including output from downscaled versions (HIPOCAS and ARPERA) of the NCEP/NCAR and ECMWF reanalyses. The downscaled fields reveal small scale forcing features (including jet-like structures over the dense water formation sites) that are not present in the coarser resolution reanalysis datasets. They also show greater variability in the forcing of the Aegean and the Gulf of Lions than the Adriatic Sea. The differences between the forcing distributions of the Aegean and Adriatic will be discussed in detail and will be advanced as a potential cause for variations in frequency of dense water formation in these two regions.

  1. Climate Impacts on Sea Turtle Breeding Phenology in Greece and Associated Foraging Habitats in the Wider Mediterranean Region.

    PubMed

    Patel, Samir H; Morreale, Stephen J; Saba, Vincent S; Panagopoulou, Aliki; Margaritoulis, Dimitris; Spotila, James R

    2016-01-01

    Sea turtles are vulnerable to climate change impacts in both their terrestrial (nesting beach) and oceanic habitats. From 1982 to 2012, air and sea surface temperatures at major high use foraging and nesting regions (n = 5) of loggerhead turtles (Caretta caretta) nesting in Greece have steadily increased. Here, we update the established relationships between sea surface temperature and nesting data from Zakynthos (latitude: 37.7°N), a major nesting beach, while also expanding these analyses to include precipitation and air temperature and additional nesting data from two other key beaches in Greece: Kyparissia Bay (latitude: 37.3°N) and Rethymno, Crete (latitude: 35.4°N). We confirmed that nesting phenology at Zakynthos has continued to be impacted by breeding season temperature; however, temperature has no consistent relationship with nest numbers, which are declining on Zakynthos and Crete but increasing at Kyparissia. Then using statistically downscaled outputs of 14 climate models assessed by the Intergovernmental Panel on Climate Change (IPCC), we projected future shifts in nesting for these populations. Based on the climate models, we projected that temperature at the key foraging and breeding sites (Adriatic Sea, Aegean Sea, Crete, Gulf of Gabès and Zakynthos/Kyparissia Bay; overall latitudinal range: 33.0°-45.8°N) for loggerhead turtles nesting in Greece will rise by 3-5°C by 2100. Our calculations indicate that the projected rise in air and ocean temperature at Zakynthos could cause the nesting season in this major rookery to shift to an earlier date by as much as 50-74 days by 2100. Although an earlier onset of the nesting season may provide minor relief for nest success as temperatures rise, the overall climatic changes to the various important habitats will most likely have an overall negative impact on this population.

  2. Climate Impacts on Sea Turtle Breeding Phenology in Greece and Associated Foraging Habitats in the Wider Mediterranean Region

    PubMed Central

    Morreale, Stephen J.; Saba, Vincent S.; Panagopoulou, Aliki; Margaritoulis, Dimitris; Spotila, James R.

    2016-01-01

    Sea turtles are vulnerable to climate change impacts in both their terrestrial (nesting beach) and oceanic habitats. From 1982 to 2012, air and sea surface temperatures at major high use foraging and nesting regions (n = 5) of loggerhead turtles (Caretta caretta) nesting in Greece have steadily increased. Here, we update the established relationships between sea surface temperature and nesting data from Zakynthos (latitude: 37.7°N), a major nesting beach, while also expanding these analyses to include precipitation and air temperature and additional nesting data from two other key beaches in Greece: Kyparissia Bay (latitude: 37.3°N) and Rethymno, Crete (latitude: 35.4°N). We confirmed that nesting phenology at Zakynthos has continued to be impacted by breeding season temperature; however, temperature has no consistent relationship with nest numbers, which are declining on Zakynthos and Crete but increasing at Kyparissia. Then using statistically downscaled outputs of 14 climate models assessed by the Intergovernmental Panel on Climate Change (IPCC), we projected future shifts in nesting for these populations. Based on the climate models, we projected that temperature at the key foraging and breeding sites (Adriatic Sea, Aegean Sea, Crete, Gulf of Gabès and Zakynthos/Kyparissia Bay; overall latitudinal range: 33.0°—45.8°N) for loggerhead turtles nesting in Greece will rise by 3–5°C by 2100. Our calculations indicate that the projected rise in air and ocean temperature at Zakynthos could cause the nesting season in this major rookery to shift to an earlier date by as much as 50–74 days by 2100. Although an earlier onset of the nesting season may provide minor relief for nest success as temperatures rise, the overall climatic changes to the various important habitats will most likely have an overall negative impact on this population. PMID:27332550

  3. On how climate variability influences regional sea level change

    NASA Astrophysics Data System (ADS)

    Brunnabend, Sandra-Esther; Kusche, Jürgen; Rietbroek, Roelof; Forootan, Ehsan

    2016-04-01

    Regional trends in sea level change are strongly influenced by climate variations, such as ENSO (El-Nino Southern Oscillation), the IOD (Indian Ocean Dipole), or the PDO (Pacific Decadal Oscillation). Hence, before computing long term regional sea level change, these sea level variations need to be taken into account as they lead to strong dependencies of computed regional sea level trends on the time period of the investigation. In this study, sea level change during the years 1993 to 2013 is analysed to identify the dominant modes of sea level change caused by climate variations. Here, two different gridded altimetry products are analysed, namely ESA's combined CCI SeaLevel v1.1 ECV product (doi: 10.5270/esa-sea_level_cci-1993_2013-v_1.1-201412), and absolute dynamic topography produced by Ssalto/Duacs and distributed by Aviso, with support from Cnes (http://www.aviso.altimetry.fr/duacs/). Reconstructions using the different decomposition techniques including the standard principle component analysis (PCA), rotated empirical orthogonal functions (REOF) and independent component analysis (ICA) method are analysed. They are compared with sea level change modelled with the global finite-element sea-ice ocean model (FESOM). The results indicate that from the applied methods, ICA is most suitable to separate the individual climate variability signals in independent modes of sea level change. This especially holds for extracting the ENSO contribution in sea level changes, which was better separated by applying ICA, from both altimetry and modelled sea level products. In addition, it is presented how modelled sea level change reflects climate variations compared to that identified in the altimetry products.

  4. Hydrographic responses to regional covariates across the Kara Sea

    NASA Astrophysics Data System (ADS)

    Mäkinen, Jussi; Vanhatalo, Jarno

    2016-12-01

    The Kara Sea is a shelf sea in the Arctic Ocean which has a strong spatiotemporal hydrographic variation driven by river discharge, air pressure, and sea ice. There is a lack of information about the effects of environmental variables on surface hydrography in different regions of the Kara Sea. We use a hierarchical spatially varying coefficient model to study the variation of sea surface temperature (SST) and salinity (SSS) in the Kara Sea between years 1980 and 2000. The model allows us to study the effects of climatic (Arctic oscillation index (AO)) and seasonal (river discharge and ice concentration) environmental covariates on hydrography. The hydrographic responses to covariates vary considerably between different regions of the Kara Sea. River discharge decreases SSS in the shallow shelf area and has a neutral effect in the northern Kara Sea. The responses of SST and SSS to AO show the effects of different wind and air pressure conditions on water circulation and hence on hydrography. Ice concentration has a constant effect across the Kara Sea. We estimated the average SST and SSS in the Kara Sea in 1980-2000. The average August SST over the Kara Sea in 1995-2000 was higher than the respective average in 1980-1984 with 99.9% probability and August SSS decreased with 77% probability between these time periods. We found a support that the winter season AO has an impact on the summer season hydrography, and temporal trends may be related to the varying level of winter season AO index.

  5. Baltic Earth - Earth System Science for the Baltic Sea Region

    NASA Astrophysics Data System (ADS)

    Meier, Markus; Rutgersson, Anna; Lehmann, Andreas; Reckermann, Marcus

    2014-05-01

    The Baltic Sea region, defined as its river catchment basin, spans different climate and population zones, from a temperate, highly populated, industrialized south with intensive agriculture to a boreal, rural north. It encompasses most of the Scandinavian Peninsula in the west; most of Finland and parts of Russia, Belarus, and the Baltic states in the east; and Poland and small parts of Germany and Denmark in the south. The region represents an old cultural landscape, and the Baltic Sea itself is among the most studied sea areas of the world. Baltic Earth is the new Earth system research network for the Baltic Sea region. It is the successor to BALTEX, which was terminated in June 2013 after 20 years and two successful phases. Baltic Earth stands for the vision to achieve an improved Earth system understanding of the Baltic Sea region. This means that the research disciplines of BALTEX continue to be relevant, i.e. atmospheric and climate sciences, hydrology, oceanography and biogeochemistry, but a more holistic view of the Earth system encompassing processes in the atmosphere, on land and in the sea as well as in the anthroposphere shall gain in importance in Baltic Earth. Specific grand research challenges have been formulated, representing interdisciplinary research questions to be tackled in the coming years. A major means will be scientific assessments of particular research topics by expert groups, similar to the BACC approach, which shall help to identify knowledge gaps and develop research strategies. Preliminary grand challenges and topics for which Working Groups have been installed include: • Salinity dynamics in the Baltic Sea • Land-Sea biogeochemical feedbacks in the Baltic Sea region • Natural hazards and extreme events in the Baltic Sea region • Understanding sea level dynamics in the Baltic Sea • Understanding regional variability of water and energy exchange • Utility of Regional Climate Models • Assessment of Scenario Simulations

  6. Contemporary kinematics of the southern Aegean and the Mediterranean Ridge

    NASA Astrophysics Data System (ADS)

    Kreemer, Corné; Chamot-Rooke, Nicolas

    2004-06-01

    direction of S24°W +/- 1° towards stable Nubia (NU). Our model confirms that there is a clear divergence between the western and eastern Hellenic arc and we argue for a causal relation between the outward motion of the arc and the gradient in the regional geoid anomaly. Our results suggest that a significant driving source of the surface velocity field lies south of the Hellenic arc and only for the southeastern Aegean could there be some effect as a result of gravitational collapse associated with density differences within the overriding plate.

  7. Elastic-Anelastic properties beneath the Aegean inferred from long period Rayleigh Waves

    NASA Astrophysics Data System (ADS)

    Kassaras, I.; Louis, F.; Makropoulos, K.; Kaviris, G.

    2007-12-01

    This work is towards contributing to the better knowledge of the deep structure of the Aegean by introducing experimental elastic and anelastic parameters via the study of long period Rayleigh waves. For this scope path- average phase velocities and attenuation coefficients of fundamental Rayleigh waves crossing the Aegean were extracted over the period range 10-100 s. It is mean worth that it is the first time that anelastic parameters of the long period wavefield are determined for the region. The wavetrains were recorded at the broadband stations installed some years ago in the Aegean region for the SEISFAULTGREECE project. The stochastic inversion algorithm has been used to derive 36 path-average models of shear velocity and 19 path-average models of inverse shear Q down to 200 km. Average over the study region shear Q values at depths from 0 to 200 km range between 29±13. The observed low shear Q likely indicate that fluids reside in lower crustal, as well as upper mantle depths. Furthermore, the elastic and anelastic 1-D path-average models were combined in a continuous regionalization tomographic scheme to obtain a 3-D model of shear velocity variation down to 200 km and a 3-D model of inverse shear Q variation down to 120 km. The most prominent features in the tomograms are: a) A low shear velocity zone in the back-arc region, especially in the central and north Aegean. This region is located south of the North Aegean Trough (the western edge of the North Anatolian Fault) and correlates well with the derived anelastic tomograms which present high attenuation in this area. b) A high velocity/low attenuation zone in South Aegean indicating the subducted African lithosphere beneath the Aegean. The zone in central and north Aegean characterized by low velocities/high attenuation is compatible with a region of high extensional strain rates, recent volcanism and high heat flow. These observations suggest a hot or perhaps partially molten upper mantle and

  8. Can regional climate engineering save the summer Arctic sea ice?

    NASA Astrophysics Data System (ADS)

    Tilmes, S.; Jahn, Alexandra; Kay, Jennifer E.; Holland, Marika; Lamarque, Jean-Francois

    2014-02-01

    Rapid declines in summer Arctic sea ice extent are projected under high-forcing future climate scenarios. Regional Arctic climate engineering has been suggested as an emergency strategy to save the sea ice. Model simulations of idealized regional dimming experiments compared to a business-as-usual greenhouse gas emission simulation demonstrate the importance of both local and remote feedback mechanisms to the surface energy budget in high latitudes. With increasing artificial reduction in incoming shortwave radiation, the positive surface albedo feedback from Arctic sea ice loss is reduced. However, changes in Arctic clouds and the strongly increasing northward heat transport both counteract the direct dimming effects. A 4 times stronger local reduction in solar radiation compared to a global experiment is required to preserve summer Arctic sea ice area. Even with regional Arctic dimming, a reduction in the strength of the oceanic meridional overturning circulation and a shut down of Labrador Sea deep convection are possible.

  9. Time of emergence for regional sea-level change

    NASA Astrophysics Data System (ADS)

    Lyu, Kewei; Zhang, Xuebin; Church, John A.; Slangen, Aimée B. A.; Hu, Jianyu

    2014-11-01

    Determining the time when the climate change signal from increasing greenhouse gases exceeds and thus emerges from natural climate variability (referred to as the time of emergence, ToE) is an important climate change issue. Previous ToE studies were mainly focused on atmospheric variables. Here, based on three regional sea-level projection products available to 2100, which have increasing complexity in terms of included processes, we estimate the ToE for sea-level changes relative to the reference period 1986-2005. The dynamic sea level derived from ocean density and circulation changes alone leads to emergence over only limited regions. By adding the global-ocean thermal expansion effect, 50% of the ocean area will show emergence with rising sea level by the early-to-middle 2040s. Including additional contributions from land ice mass loss, land water storage change and glacial isostatic adjustment generally enhances the signal of regional sea-level rise (except in some regions with decreasing total sea levels), which leads to emergence over more than 50% of the ocean area by 2020. The ToE for total sea level is substantially earlier than that for surface air temperature and exhibits little dependence on the emission scenarios, which means that our society will face detectable sea-level change and its potential impacts earlier than surface air warming.

  10. On the characteristics of sea breezes over Nigerian coastal region

    NASA Astrophysics Data System (ADS)

    Abatan, Abayomi A.; Abiodun, Babatunde J.; Omotosho, Bayo J.

    2014-04-01

    This paper describes the characteristics of sea breezes over the coastal region of Nigeria. While considerable attention has been paid to monsoon circulation over this coastal region, there is virtually no information in literature on sea breezes over the region. This study analyzed 5 years (1979-1983) data of hourly temperature and wind speed and direction from four coastal stations in Nigerian—Lagos, Warri, Port-Harcourt, and Calabar—in order to examine the characteristics of the sea breeze in the region. The results show that sea breeze usually started between 1000 and 1200 UTC, attained maximum strength of about 2-5 m s-1 in the afternoon around 1500-1600 UTC and subsided between 2000 and 2200 UTC. Consistent with maxima temperature contrast between land and sea, the maximum frequency of sea breeze occurs in February-May and September-November, with duration of about 11-13 h. The diurnal variation of wind vectors with time, portrayed by means of hodograph, shows that sea breeze rotates clockwise and anticlockwise over the region. We found that only the stations adjacent to bay demonstrate clockwise rotation during the day.

  11. Chronology for the Aegean Late Bronze Age 1700-1400 B.C.

    PubMed

    Manning, Sturt W; Ramsey, Christopher Bronk; Kutschera, Walter; Higham, Thomas; Kromer, Bernd; Steier, Peter; Wild, Eva M

    2006-04-28

    Radiocarbon (carbon-14) data from the Aegean Bronze Age 1700-1400 B.C. show that the Santorini (Thera) eruption must have occurred in the late 17th century B.C. By using carbon-14 dates from the surrounding region, cultural phases, and Bayesian statistical analysis, we established a chronology for the initial Aegean Late Bronze Age cultural phases (Late Minoan IA, IB, and II). This chronology contrasts with conventional archaeological dates and cultural synthesis: stretching out the Late Minoan IA, IB, and II phases by approximately 100 years and requiring reassessment of standard interpretations of associations between the Egyptian and Near Eastern historical dates and phases and those in the Aegean and Cyprus in the mid-second millennium B.C.

  12. Plant speciation in continental island floras as exemplified by Nigella in the Aegean Archipelago.

    PubMed

    Comes, Hans Peter; Tribsch, Andreas; Bittkau, Christiane

    2008-09-27

    Continental shelf island systems, created by rising sea levels, provide a premier setting for studying the effects of geographical isolation on non-adaptive radiation and allopatric speciation brought about by genetic drift. The Aegean Archipelago forms a highly fragmented complex of mostly continental shelf islands that have become disconnected from each other and the mainland in relatively recent geological times (ca <5.2 Ma). These ecologically fairly homogenous islands thus provide a suitable biogeographic context for assessing the relative influences of past range fragmentation, colonization, gene flow and drift on taxon diversification. Indeed, recent molecular biogeographic studies on the Aegean Nigella arvensis complex, combining phylogenetic, phylogeographic and population level approaches, exemplify the importance of allopatry and genetic drift coupled with restricted gene flow in driving plant speciation in this continental archipelago at different temporal and spatial scales. While the recent (Late Pleistocene) radiation of Aegean Nigella, as well as possible instances of incipient speciation (in the Cyclades), is shown to be strongly conditioned by (palaeo)geographic factors (including changes in sea level), shifts in breeding system (selfing) and associated isolating mechanisms have also contributed to this radiation. By contrast, founder event speciation has probably played only a minor role, perhaps reflecting a migratory situation typical for continental archipelagos characterized by niche pre-emption because of a long established resident flora. Overall, surveys of neutral molecular markers in Aegean Nigella have so far revealed population genetic processes that conform remarkably well to predictions raised by genetic drift theory. The challenge is now to gain more direct insights into the relative importance of the role of genetic drift, as opposed to natural selection, in the phenotypic and reproductive divergence among these Aegean plant

  13. Lithospheric strength and elastic thickness of the Barents Sea and Kara Sea region

    NASA Astrophysics Data System (ADS)

    Gac, Sébastien; Klitzke, Peter; Minakov, Alexander; Faleide, Jan Inge; Scheck-Wenderoth, Magdalena

    2016-11-01

    Interpretation of tomography data indicates that the Barents Sea region has an asymmetric lithospheric structure characterized by a thin and hot lithosphere in the west and a thick and cold lithosphere in the east. This suggests that the lithosphere is stronger in the east than in the west. This asymmetric lithosphere strength structure may have a strong control on the lithosphere response to tectonic and surface processes. In this paper, we present computed strength and effective elastic thickness maps of the lithosphere of the Barents Sea and Kara Sea region. Those are estimated using physical parameters from a 3D lithospheric model of the Barents Sea and Kara Sea region. The lithospheric strength is computed assuming a temperature-dependent ductile and brittle rheology for sediments, crust and mantle lithosphere. Results show that lithospheric strength and elastic thickness are mostly controlled by the lithosphere thickness. The model generally predicts much larger lithospheric strength and elastic thickness for the Proterozoic parts of the East Barents Sea and Kara Sea. Locally, the thickness and lithology of the continental crust disturb this general trend. At last, the gravitational potential energy (GPE) is computed. Our results show that the difference in GPE between the Barents Sea and the Mid-Atlantic Ridge provides a net horizontal force large enough to cause contraction in the western and central Barents Sea.

  14. Relating Regional Arctic Sea Ice and climate extremes over Europe

    NASA Astrophysics Data System (ADS)

    Ionita-Scholz, Monica; Grosfeld, Klaus; Lohmann, Gerrit; Scholz, Patrick

    2016-04-01

    The potential increase of temperature extremes under climate change is a major threat to society, as temperature extremes have a deep impact on environment, hydrology, agriculture, society and economy. Hence, the analysis of the mechanisms underlying their occurrence, including their relationships with the large-scale atmospheric circulation and sea ice concentration, is of major importance. At the same time, the decline in Arctic sea ice cover during the last 30 years has been widely documented and it is clear that this change is having profound impacts at regional as well as planetary scale. As such, this study aims to investigate the relation between the autumn regional sea ice concentration variability and cold winters in Europe, as identified by the numbers of cold nights (TN10p), cold days (TX10p), ice days (ID) and consecutive frost days (CFD). We analyze the relationship between Arctic sea ice variation in autumn (September-October-November) averaged over eight different Arctic regions (Barents/Kara Seas, Beaufort Sea, Chukchi/Bering Seas, Central Arctic, Greenland Sea, Labrador Sea/Baffin Bay, Laptev/East Siberian Seas and Northern Hemisphere) and variations in atmospheric circulation and climate extreme indices in the following winter season over Europe using composite map analysis. Based on the composite map analysis it is shown that the response of the winter extreme temperatures over Europe is highly correlated/connected to changes in Arctic sea ice variability. However, this signal is not symmetrical for the case of high and low sea ice years. Moreover, the response of temperatures extreme over Europe to sea ice variability over the different Arctic regions differs substantially. The regions which have the strongest impact on the extreme winter temperature over Europe are: Barents/Kara Seas, Beaufort Sea, Central Arctic and the Northern Hemisphere. For the years of high sea ice concentration in the Barents/Kara Seas there is a reduction in the number

  15. Forecasting skill assessment of an oil spill simulation system in the NE Aegean and atmospheric forcing perturbation experiments

    NASA Astrophysics Data System (ADS)

    Kailas, Marios; Chrysagi, Eyrydice; Sofianos, Sarantis

    2016-04-01

    In the present study, the predictive skill of an oil spill simulation system implemented in the Northern Aegean Sea was evaluated using field observations from surface drifters, provided in the framework of the TOSCA project. The system produces satisfactory results as in most cases the forecasting error is quite small, allowing the operational use of the forecast. In order to examine the sensitivity of the forecast to atmospheric forcing, additional simulations with perturbed atmospheric conditions were performed, using a time-shifting technique. In most experiments the differences between the simulations are relatively small, most likely due to slow oceanic response to variations in the wind fields. From the individual simulations an ensemble forecast was created, the results of which were also compared with the observations. The results suggest that by applying this method a safer forecast can be provided, especially regarding cases for which the wind-driven circulation is predominant. However, in cases where the circulation is characterized by intense velocity gradients (in the NE Aegean this is associated with the thermohaline front created by the Black Sea Water inflow), larger differences are present. They are related to imprecise representation of the location of the front. In these cases, the ensemble method produced no significant improvement since the relatively small differences between the trajectories of the ensemble members indicate that the position of the front in not significantly affected by the wind perturbations, based on the spatio-temporal scales examined. It is concluded that in regions with large spatio-temporal variability, an ensemble forecast produced by simulations generated from perturbed initial conditions could possibly lead to more robust results.

  16. Atmospheric forcing of sea ice anomalies in the Ross Sea Polynya region

    NASA Astrophysics Data System (ADS)

    Dale, Ethan; McDonald, Adrian; Rack, Wolfgang

    2016-04-01

    Despite warming trends in global temperatures, sea ice extent in the southern hemisphere has shown an increasing trend over recent decades. Wind-driven sea ice export from coastal polynyas is an important source of sea ice production. Areas of major polynyas in the Ross Sea, the region with largest increase in sea ice extent, have been suggested to produce the vast amount of the sea ice in the region. We investigate the impacts of strong wind events on polynyas and the subsequent sea ice production. We utilize Bootstrap sea ice concentration (SIC) measurements derived from satellite based, Special Sensor Microwave Imager (SSM/I) brightness temperature images. These are compared with surface wind measurements made by automatic weather stations of the University of Wisconsin-Madison Antarctic Meteorology Program. Our analysis focusses on the winter period defined as 1st April to 1st November in this study. Wind data was used to classify each day into characteristic regimes based on the change of wind speed. For each regime, a composite of SIC anomaly was formed for the Ross Sea region. We found that persistent weak winds near the edge of the Ross Ice Shelf are generally associated with positive SIC anomalies in the Ross Sea polynya area (RSP). Conversely we found negative SIC anomalies in this area during persistent strong winds. By analyzing sea ice motion vectors derived from SSM/I brightness temperatures, we find significant sea ice motion anomalies throughout the Ross Sea during strong wind events. These anomalies persist for several days after the strong wing event. Strong, negative correlations are found between SIC within the RSP and wind speed indicating that strong winds cause significant advection of sea ice in the RSP. This rapid decrease in SIC is followed by a more gradual recovery in SIC. This increase occurs on a time scale greater than the average persistence of strong wind events and the resulting Sea ice motion anomalies, highlighting the production

  17. Regional dependence in the rapid loss of Arctic sea ice

    NASA Astrophysics Data System (ADS)

    Close, Sally; Houssais, Marie-Noëlle; Herbaut, Christophe

    2016-04-01

    The accelerating rate of sea ice decline in the Arctic, particularly in the summer months, has been well documented by previous studies. However, the methods of analysis used to date have tended to employ pre-defined regions over which to determine sea ice loss, potentially masking regional variability within these regions. Similarly, evidence of acceleration has frequently been based on decade-to-decade comparisons that do not precisely quantify the timing of the increase in rate of decline. In this study, we address this issue by quantifying the onset time of rapid loss in sea ice concentration on a point-by-point basis, using an objective method applied to satellite passive microwave data. Seasonal maps of onset time are produced, and reveal strong regional dependency, with differences of up to 20 years in onset time between the various subregions of the Arctic. In certain cases, such as the Laptev Sea, strong spatial variability is found even at the regional scale, suggesting that caution should be employed in the use of geographically-based region definitions that may be misaligned with the physical response. The earliest onset times are found in the Pacific sector, where certain areas undergo a transition ca. 1992. In contrast, onset times in the Atlantic sector are much more recent. Rates of decline prior to and following the onset of rapid decline are calculated, and suggest that the post-onset rate of loss is weakest in the Pacific sector and greatest in the Barents Sea region. Coherency is noted in the season-to-season response, both at interannual and longer time scales. Our results describe a series of spatially self-consistent regional responses, and may be useful in understanding the primary drivers of recent sea ice loss.

  18. The spreading of the Chernobyl signature from the North Aegean waters to the Eastern Mediterranean basin

    NASA Astrophysics Data System (ADS)

    Papucci, C.; Delfanti, R.; Lorenzelli, R.; Zervakis, V.; Georgopoulos, D.

    2003-04-01

    The Chernobyl accident (26 April 1986) produced a patchy deposition of radionuclides over the Eastern and Northern basins of the Mediterranean Sea, that was superimposed over the previous fallout from atmospheric nuclear weapon tests. The deposition of Chernobyl-derived 137Cs was particularly heavy onto the Black Sea (3000 TBq) and the Aegean -- Ionian Seas along the Greek coasts (800 TBq). Moreover, as the Black Sea still receives a delayed input of Chernobyl 137Cs from the rivers Danube and Dniepr, the output of surface water through the Dardanelles Straits constitutes a "permanent" point source of this conservative radionuclide into the North Aegean Sea. The water exiting the Dardanelles undergoes mixing with North Aegean surface water. Due to its low salinity this water acts as an insulation layer and, consequently, deep-water formation is rather infrequent in the North Aegean, taking place only at periods of reduced Black Sea outflow and/or exceptionally cold and dry winters. In the last 20 years there have been two major deep-water formation events in the North Aegean: in winter 1987 (just after the Chernobyl accident), and in winter 1993. Actually, these two episodes have deeply modified the vertical profiles of 137Cs with respect to 1984, before the Chernobyl accident. In 1999--2001, in the (isolated from advection) Lemnos and N-Skyros Basins, the 137Cs concentration increased from the surface to the bottom; in the deep waters it was about 5 Bq m-3, five times higher than in 1984. These deep waters formed in 1993, are characterised by high salinity and density and their major contributor was water of Levantine/Cretan origin. The Chernobyl input also caused a considerable increase in 137Cs concentrations in the Cretan Deep Waters flowing through the Antikythera Strait: the typical concentration in this water mass was, in 1999, 2.5 -- 2.8 Bq m-3, almost three times higher than that in the deep Cretan basin in 1984. This strong signal is spreading in the

  19. Monitoring the Dead Sea Region by Multi-Parameter Stations

    NASA Astrophysics Data System (ADS)

    Mohsen, A.; Weber, M. H.; Kottmeier, C.; Asch, G.

    2015-12-01

    The Dead Sea Region is an exceptional ecosystem whose seismic activity has influenced all facets of the development, from ground water availability to human evolution. Israelis, Palestinians and Jordanians living in the Dead Sea region are exposed to severe earthquake hazard. Repeatedly large earthquakes (e.g. 1927, magnitude 6.0; (Ambraseys, 2009)) shook the whole Dead Sea region proving that earthquake hazard knows no borders and damaging seismic events can strike anytime. Combined with the high vulnerability of cities in the region and with the enormous concentration of historical values this natural hazard results in an extreme earthquake risk. Thus, an integration of earthquake parameters at all scales (size and time) and their combination with data of infrastructure are needed with the specific aim of providing a state-of-the-art seismic hazard assessment for the Dead Sea region as well as a first quantitative estimate of vulnerability and risk. A strong motivation for our research is the lack of reliable multi-parameter ground-based geophysical information on earthquakes in the Dead Sea region. The proposed set up of a number of observatories with on-line data access will enable to derive the present-day seismicity and deformation pattern in the Dead Sea region. The first multi-parameter stations were installed in Jordan, Israel and Palestine for long-time monitoring. All partners will jointly use these locations. All stations will have an open data policy, with the Deutsches GeoForschungsZentrum (GFZ, Potsdam, Germany) providing the hard and software for real-time data transmission via satellite to Germany, where all partners can access the data via standard data protocols.

  20. A lithosphere-scale structural model of the Barents Sea and Kara Sea region

    NASA Astrophysics Data System (ADS)

    Klitzke, P.; Faleide, J. I.; Scheck-Wenderoth, M.; Sippel, J.

    2014-07-01

    The Barents Sea and Kara Sea region as part of the European Arctic shelf, is geologically situated between the Proterozoic East-European Craton in the south and early Cenozoic passive margins in the north and the west. Proven and inferred hydrocarbon resources encouraged numerous industrial and academic studies in the last decades which brought along a wide spectrum of geological and geophysical data. By evaluating all available interpreted seismic refraction and reflection data, geological maps and previously published 3-D-models, we were able to develop a new lithosphere-scale 3-D-structural model for the greater Barents Sea and Kara Sea region. The sedimentary part of the model resolves four major megasequence boundaries (earliest Eocene, mid-Cretaceous, mid-Jurassic and mid-Permian). Downwards, the 3-D-structural model is complemented by the top crystalline crust, the Moho and a newly calculated lithosphere-asthenosphere boundary (LAB). The thickness distribution of the main megasequences delineates five major subdomains differentiating the region (the northern Kara Sea, the southern Kara Sea, the eastern Barents Sea, the western Barents Sea and the oceanic domain comprising the Norwegian-Greenland Sea and the Eurasia Basin). The vertical resolution of five sedimentary megasequences allows comparing for the first time the subsidence history of these domains directly. Relating the sedimentary structures with the deeper crustal/lithospheric configuration sheds some light on possible causative basin forming mechanisms that we discuss. The newly calculated LAB deepens from the typically shallow oceanic domain in three major steps beneath the Barents and Kara shelves towards the West-Siberian Basin in the east. Thereby, we relate the shallow continental LAB and slow/hot mantle beneath the southwestern Barents Sea with the formation of deep Paleozoic/Mesozoic rift basins. Thinnest continental lithosphere is observed beneath Svalbard and the NW Barents Sea where no

  1. BALTEX - A science broker for the Baltic Sea Region

    NASA Astrophysics Data System (ADS)

    Reckermann, M.; von Storch, H.; Langner, J.; Omstedt, A. T.

    2010-12-01

    BALTEX (the Baltic Sea Experiment) is an interdisciplinary research network of scientists involved in environmental research dedicated to the Baltic Sea drainage basin (including disciplines such as meteorology, hydrology, oceanography, biogeochemistry and climate research). Originally founded in 1992 as a Continental Scale Experiment in GEWEX (the Global Energy and Water Cycle Experiment within the World Climate Research Programme (WCRP) of the World Meteorological Organization, WMO), it was intended to form a common science, communication and data platform with the overall goal to integrate efforts to gain a better understanding of the water and energy cycle in the Baltic Sea basin. BALTEX Phase II (since 2003) has extended the scope to research on regional climate change and variability, climate change impacts on biogeochemistry and water management, but also made first steps towards overarching social and political issues as cross-cutting activities in the context of the scientific objectives. An important aspect of BALTEX Phase II is a more holistic approach towards observing, understanding and modelling major environmental relevant for the entire Baltic Sea region. Parts of the BALTEX Phase II research activities thus contribute to the establishment of a high resolution integrated modelling system for Northern Europe, embedded in an Earth System Model. An outstanding product of BALTEX as a “knowledge broker” for regional political institutions is the BACC report. Following to a large extent the method of IPCC, a regional assessment report on climate change in the Baltic Sea basin was compiled, which summarizes the published scientifically legitimate knowledge on regional climate change in the Baltic Sea basin and its impacts. The assessment, known as the BACC report (BALTEX Assessment of Climate Change for the Baltic Sea Basin; BACC author team 2008, Reckermann et al., 2008) was published in 2008 as a book. A survey among climate researchers in the area

  2. Diagnostic sea ice predictability in the pan-Arctic and U.S. Arctic regional seas

    NASA Astrophysics Data System (ADS)

    Cheng, Wei; Blanchard-Wrigglesworth, Edward; Bitz, Cecilia M.; Ladd, Carol; Stabeno, Phyllis J.

    2016-11-01

    This study assesses sea ice predictability in the pan-Arctic and U.S. Arctic regional (Bering, Chukchi, and Beaufort) seas with a purpose of understanding regional differences from the pan-Arctic perspective and how predictability might change under changing climate. Lagged correlation is derived using existing output from the Community Earth System Model Large Ensemble (CESM-LE), Pan-Arctic Ice-Ocean Modeling and Assimilation System, and NOAA Coupled Forecast System Reanalysis models. While qualitatively similar, quantitative differences exist in Arctic ice area lagged correlation in models with or without data assimilation. On regional scales, modeled ice area lagged correlations are strongly location and season dependent. A robust feature in the CESM-LE is that the pan-Arctic melt-to-freeze season ice area memory intensifies, whereas the freeze-to-melt season memory weakens as climate warms, but there are across-region variations in the sea ice predictability changes with changing climate.

  3. The Middle Pleistocene archaeological record of Greece and the role of the Aegean in hominin dispersals: new data and interpretations

    NASA Astrophysics Data System (ADS)

    Tourloukis, Vangelis; Karkanas, Panagiotis

    2012-06-01

    In the debate about hominin dispersals, Greece is expected to have been among the core areas for the peopling of Eurasia, serving as a 'refugium' and source region for (re)colonizations. Yet, its early Pleistocene record is still scarce, forming a conspicuous 'gap' in the early human geography of the Mediterranean. Here we investigate this gap and provide for the first time a synthesis of the Lower Palaeolithic record of Greece. Our study adopts a geoarchaeological approach to explain the current status of the record and argues that the 'absence of evidence' should be understood as the result of the biasing effects of erosional geomorphic processes and not as an indication of a former absence of hominins. In this line, the potential for archaeological preservation and recovery is assessed as a function of landscape dynamics. Climatic seasonality, tectonic activity, high relief and marine inundations have altogether contributed to significant reworking and/or total loss of archaeological sites: in spatial terms, only about 2-5% of the Lower Palaeolithic record of Greece may have survived up to the present. On the other hand, we interpret recent geological data, which show that half of the Aegean Sea would have been subaerially exposed for most of the early Pleistocene. Our results emphasize the potentially central role of the Aegean region in hominin dispersals, both as a biogeographical landbridge and as a highly productive landscape for occupation. This conclusion opens up new prospects for future fieldwork in an area that was hitherto essentially neglected. Finally, in showing how geomorphic processes bias site distribution patterns, the results and methodological perspective developed here can be seen as having implications that are wider than the geographical limits of the Greek Peninsula: they are pertinent to the investigation and interpretation of the early Pleistocene archaeological records in the highly dynamic landscapes of southern Europe - if not in

  4. Hydrocarbon production concepts for dynamic annual sea ice regions

    SciTech Connect

    Wang, A.T.; Poplin, J.P.; Heure, C.E.

    1995-02-01

    Petroleum production from Russian seas such as the northern Timan-Pechora Basin (Pechora Sea) and the northeastern Sakhalin island Shelf (Sea of Okhotsk) is likely to occur in the near future. Several different types of offshore structures may be needed in the Russian arctic offshore to support development activities. These structures may include: a number of production structures for offshore fields, subsea pipelines, a regional tanker terminal, and ice-breaking tankers. Dynamic first-year sea ice will be a major design consideration for offshore structures considered for use in these areas. Exxon previously performed engineering studies for petroleum development in Norton Sound off the west coast of Alaska. Norton Sound is also an area of dynamic first-year sea ice, so many of the lessons learned and much of the technology developed for that region are considered to be applicable to the Pechora Sea and the Sakhalin Shelf. Several of the concepts for production structures, pipelines, terminals, and tankers are presented along with a discussion of the related ice technology. Field and laboratory studies undertaken to collect environmental data are described along with a probabilistic load calculation procedure for structure design. More recent work by Exxon to enhance technology since the Norton Sound studies is also presented along with a discussion of recommended future work activities.

  5. Egyptian Red Sea petroleum geology and regional geophysical evaluation

    SciTech Connect

    Ahmed, Y.H.; Shalaan, A.A.; Zaki, H.A. )

    1991-08-01

    The World Bank-executed Red Sea/Gulf of Aden Regional Hydrocarbon Study Project was organized to synthesize data on the Red Sea and Gulf of Aden basins. The primary objectives were to encourage increased hydrocarbon exploration techniques basin wide, and to train national geoscientists in exploration techniques. The study was carried out be task forces for each participating country, working in Cairo under the supervision of World Bank technical personnel. In addition, biostratigraphic, paleoenvironmental, and lithostratigraphic analyses by Robertson Group and geochemical studies and BEICIP were carried out on well cuttings and core samples. The study of the Egyptian Red Sea was based on public-domain exploration data, published information, and data released by operating companies. This included reports, sections, and wireline logs from 13 well, samples from ten wells for biostratigraphic analysis, and samples from eight wells for geochemical analysis. Interpretation was carried out on 4,350 line-km of seismic data selected from a grid of 19,000 line-km of data. Four horizons were identified on a regional basis, including the sea floor, top, and near base of middle to upper Miocene evaporites, and approximate acoustic basement. The results show that the Egyptian Red Sea is similar to the better known, productive Gulf of Suez in many respects, including overall tectonic evolution and structural style, present geothermal gradients, and Miocene to Holocene stratigraphic sequence. Based in part on this similarity, the Egyptian Red Sea appears to contain the necessary elements for an attractive petroleum potential.

  6. How Changing Human Lifestyles are Shaping Europe's Regional Seas

    NASA Astrophysics Data System (ADS)

    Mee, L. D.; Lowe, C. D.; Langmead, O.; McQuatters-Gollop, A.; Attrill, M.; Cooper, P.; Gilbert, A.; Knudsen, S.; Garnacho, E.

    2007-05-01

    European society is experiencing unprecedented changes triggered by expansion of the European Union, the fall of Communism, economic growth and the onset of globalisation. Europe's regional seas, the Baltic, Black Sea, Mediterranean and North-East Atlantic (including the North Sea), provide key goods and services to the human population but have suffered from severe degradation in past decades. Their integrity as coupled social and ecological systems depends on how humanity will anticipate potential problems and deal with its ecological footprint in the future. We report the outcome of an EU-funded 15-country, 28 institution project entitled European Lifestyles and Marine Ecosystems (ELME). Our studies were designed to inform new EU policy and legislation that incorporates Ecosystem-Based Management. ELME has modelled the key relationships between economic and social drivers (D), environmental pressures (P) and changes in the state of the environment (S) in Europe's regional seas. We examined four key issues in each sea: habitat change, eutrophication, chemical pollution and fisheries. We developed conceptual models for each regional sea and employed a novel stochastic modelling technique to examine the interrelationship between key components of the conceptual models. We used the models to examine 2-3 decade projections of current trends in D, P and S and how a number of alternative development scenarios might modify these trends. These simulations demonstrate the vulnerability of Europe's seas to human pressure. As affluence increases in countries acceding to the EU, so does the demand for marine goods and services. There are `winners' and `losers' amongst marine species; the winners are often species that are opportunistic invaders or those with low economic value. In the case of eutrophication, semi-enclosed seas such as the Baltic or Black Sea are already affected by the `legacy of the past'; nutrients that have accumulated in soils, ground waters and

  7. A Study of Mobile Trough Genesis Over The Yellow Sea-East China Sea Region

    DTIC Science & Technology

    2011-07-21

    Mongolian Plateau. The maximum that extends over the Yellow Sea and East China Sea is the only region of enhanced mobile trough formation which is...Gammon used PTD to further investigate mobile troughs and extratropical cyclones. An investigation of mobile trough formation over the Mongolian Plateau...over the Mongolian plateau. The results from the previous studies provide a measure of confidence for this research. Two case studies were chosen using

  8. Droughts in the Miocene of the Black Sea region

    NASA Astrophysics Data System (ADS)

    Vasiliev, Iuliana; Reichart, Gert-Jan; Grothe, Arjen; Krijgsman, Wout

    2016-04-01

    Since Miocene the Black Sea has been highly sensitive to fluctuations in the hydrological cycle. These fluctuations were principally determined by Black Sea's recurrently restricted connections to the Open Ocean and by its specific paleogeographic location between the dry Mediterranean domain and more humid higher northern latitudes. To determine the nature of changes in the hydrological budget of the Black Sea occurring during the late Miocene we use compound-specific hydrogen isotope ratios on terrestrial and aquatic biomarkers extracted from two different locations: 1) the sedimentary succession of Zhelezniy Rog land based section of Taman in Russia and 2) the deep sea sedimentary succession recovered in 1975 from the Black Sea (DSDP 42B, Hole 380A). The carbon and hydrogen isotopic composition of n-alkanes as well as alkenones and palynology indicate large environmental changes in the Black Sea and/or in the sources of the water entering the Black Sea during the late Miocene. The hydrogen isotopes of alkenones, showing an enrichment of more than 80 ‰ at the end of the Miocene, imply a major shift in basin hydrology, possibly resulting in severely increased salinity. These changes in hydrogen isotopic composition of the alkenones concur both with sharp shifts in reconstructed sea surface temperature and palynological assemblages. Two intervals with negative water budget were identified, most likely caused by enhanced evaporation. The older and longer dry/evaporative phase predates the Maeotian/Pontian boundary (regional stages) at ~6.1 Ma. The younger negative water budget phase is partly coeval to the Messinian salinity crisis of Mediterranean. Both shifts to highly evaporative conditions are recorded in both Taman Peninsula (Russia) and DSDP 42B 380A locations. These recurrent dryer phases were, most likely, the result of important hydrological changes over a significantly larger area around the Black Sea area during the upper Miocene.

  9. Early farmers from across Europe directly descended from Neolithic Aegeans.

    PubMed

    Hofmanová, Zuzana; Kreutzer, Susanne; Hellenthal, Garrett; Sell, Christian; Diekmann, Yoan; Díez-Del-Molino, David; van Dorp, Lucy; López, Saioa; Kousathanas, Athanasios; Link, Vivian; Kirsanow, Karola; Cassidy, Lara M; Martiniano, Rui; Strobel, Melanie; Scheu, Amelie; Kotsakis, Kostas; Halstead, Paul; Triantaphyllou, Sevi; Kyparissi-Apostolika, Nina; Urem-Kotsou, Dushka; Ziota, Christina; Adaktylou, Fotini; Gopalan, Shyamalika; Bobo, Dean M; Winkelbach, Laura; Blöcher, Jens; Unterländer, Martina; Leuenberger, Christoph; Çilingiroğlu, Çiler; Horejs, Barbara; Gerritsen, Fokke; Shennan, Stephen J; Bradley, Daniel G; Currat, Mathias; Veeramah, Krishna R; Wegmann, Daniel; Thomas, Mark G; Papageorgopoulou, Christina; Burger, Joachim

    2016-06-21

    Farming and sedentism first appeared in southwestern Asia during the early Holocene and later spread to neighboring regions, including Europe, along multiple dispersal routes. Conspicuous uncertainties remain about the relative roles of migration, cultural diffusion, and admixture with local foragers in the early Neolithization of Europe. Here we present paleogenomic data for five Neolithic individuals from northern Greece and northwestern Turkey spanning the time and region of the earliest spread of farming into Europe. We use a novel approach to recalibrate raw reads and call genotypes from ancient DNA and observe striking genetic similarity both among Aegean early farmers and with those from across Europe. Our study demonstrates a direct genetic link between Mediterranean and Central European early farmers and those of Greece and Anatolia, extending the European Neolithic migratory chain all the way back to southwestern Asia.

  10. Early farmers from across Europe directly descended from Neolithic Aegeans

    PubMed Central

    Hofmanová, Zuzana; Kreutzer, Susanne; Hellenthal, Garrett; Sell, Christian; Diekmann, Yoan; Díez-del-Molino, David; van Dorp, Lucy; López, Saioa; Kousathanas, Athanasios; Link, Vivian; Kirsanow, Karola; Cassidy, Lara M.; Martiniano, Rui; Strobel, Melanie; Scheu, Amelie; Kotsakis, Kostas; Halstead, Paul; Triantaphyllou, Sevi; Kyparissi-Apostolika, Nina; Ziota, Christina; Adaktylou, Fotini; Gopalan, Shyamalika; Bobo, Dean M.; Winkelbach, Laura; Blöcher, Jens; Unterländer, Martina; Leuenberger, Christoph; Çilingiroğlu, Çiler; Horejs, Barbara; Gerritsen, Fokke; Shennan, Stephen J.; Bradley, Daniel G.; Currat, Mathias; Veeramah, Krishna R.; Thomas, Mark G.; Papageorgopoulou, Christina; Burger, Joachim

    2016-01-01

    Farming and sedentism first appeared in southwestern Asia during the early Holocene and later spread to neighboring regions, including Europe, along multiple dispersal routes. Conspicuous uncertainties remain about the relative roles of migration, cultural diffusion, and admixture with local foragers in the early Neolithization of Europe. Here we present paleogenomic data for five Neolithic individuals from northern Greece and northwestern Turkey spanning the time and region of the earliest spread of farming into Europe. We use a novel approach to recalibrate raw reads and call genotypes from ancient DNA and observe striking genetic similarity both among Aegean early farmers and with those from across Europe. Our study demonstrates a direct genetic link between Mediterranean and Central European early farmers and those of Greece and Anatolia, extending the European Neolithic migratory chain all the way back to southwestern Asia. PMID:27274049

  11. Atmospheric forcing of sea ice anomalies in the Ross Sea polynya region

    NASA Astrophysics Data System (ADS)

    Dale, Ethan R.; McDonald, Adrian J.; Coggins, Jack H. J.; Rack, Wolfgang

    2017-01-01

    We investigate the impacts of strong wind events on the sea ice concentration within the Ross Sea polynya (RSP), which may have consequences on sea ice formation. Bootstrap sea ice concentration (SIC) measurements derived from satellite SSM/I brightness temperatures are correlated with surface winds and temperatures from Ross Ice Shelf automatic weather stations (AWSs) and weather models (ERA-Interim). Daily data in the austral winter period were used to classify characteristic weather regimes based on the percentiles of wind speed. For each regime a composite of a SIC anomaly was formed for the entire Ross Sea region and we found that persistent weak winds near the edge of the Ross Ice Shelf are generally associated with positive SIC anomalies in the Ross Sea polynya and vice versa. By analyzing sea ice motion vectors derived from the SSM/I brightness temperatures we find significant sea ice motion anomalies throughout the Ross Sea during strong wind events, which persist for several days after a strong wind event has ended. Strong, negative correlations are found between SIC and AWS wind speed within the RSP indicating that strong winds cause significant advection of sea ice in the region. We were able to partially recreate these correlations using colocated, modeled ERA-Interim wind speeds. However, large AWS and model differences are observed in the vicinity of Ross Island, where ERA-Interim underestimates wind speeds by a factor of 1.7 resulting in a significant misrepresentation of RSP processes in this area based on model data. Thus, the cross-correlation functions produced by compositing based on ERA-Interim wind speeds differed significantly from those produced with AWS wind speeds. In general the rapid decrease in SIC during a strong wind event is followed by a more gradual recovery in SIC. The SIC recovery continues over a time period greater than the average persistence of strong wind events and sea ice motion anomalies. This suggests that sea ice

  12. Red Sea Kinematics in Relation to the Regional Tectonics Setting

    NASA Astrophysics Data System (ADS)

    Alotaibi, T.; Furlong, K. P.

    2015-12-01

    The Red sSea extensional system started approximately 22+3 Ma. Although, there is evidence that lithospheric weakening and associated incipient extension may have taken place since 30 Ma. There is oceanic crust found in the southern part of the rift, while the northern-most part still involves continental stretching. Meantime magnetic anomalies have been observed for the southern rift, the northern rift is characterized by several deeps where magnetic anomalies have been observed as well as an indication of the transition from continental to oceanic rifting. GPS stations along the Red Sea are consistent with kinematics implied from the magnetic anomalies - an opening rate in the southern part of ~ 15 mm/yr relative to Eurasia fixed while the opening rate in the is ~8 mm/yr. This significant decreasing of the opening rate towards the north implies complexity within the Red Sea extensional system.Our purpose here is to place the Red Sea extensional kinematics within the regional tectonics context by combining constraints on the rate or style of extension within the Red Sea with tectonic activities on the adjacent continental regions. To accomplish this, we will model the extensional kinematics through time by comparing recent kinematics based on the geophysical observations with ones that based on geological observations. In terms of present-day geophysical observations, we have GPS and magnetic anomalies data, and crustal and lithospheric thickness. Geological observations primarily come from stratigraphic and structural data sets.Our overall target is to construct a tectonic model that links the timing of the change in the style and extensional rate with the tectonic activities in Afar, Gulf of Aden, Zagros, Dead Sea fault and Anatolian region.

  13. Late holocene climate changes in the Sea of Azov region

    NASA Astrophysics Data System (ADS)

    Matishov, G. G.; Novenko, E. Yu.; Krasnorutskaya, K. V.

    2012-05-01

    The results of paleoclimatic reconstructions made with the help of the information-statistical method developed by V.A. Klimanov based on palynological data from the Sea of Azov bottom sediments. For the period of the last 3000 years, four phases of warm and dry climates and three phases of relatively cool and humid climates were identified. The latter phases were characterized by wider expansion of tree vegetation in the region around the Sea of Azov. The range of mean annual temperatures between warmer and cooler intervals was about 4°C.

  14. Petroleum geology of Azov-Black Sea region

    SciTech Connect

    Lukin, A.; Trofimenko, G.

    1995-08-01

    The main features of tectonics, stratigraphy, paleogeography, lithology, hydrogeology, geothermics and hydrocarbon-bearingness of Azov-Black Sea Region are characterized on the basis of present-day data. Among the most prospective petroliferous complexes one ought to mention: Paleozoic (S - D - C{sub 1}) of Near-Dobrudga foredeep, Triassic - Jurassic of the Black Sea (shelf and continental slope); Lower Cretaceous of the various parts of the Region; Upper Cretaceous of the Black Sea shelf; Paleocene-Eocene of Azov Sea. In addition certain prospects are connected with Precambrian and Paleozoic basements within conjunction zone between Eastern-Europe platform and Scythian plate. Geodynamic evolution of the Region is considered with determination of tension and compression stages and characteristic of the main regularities of diapirs, mud volcanos, swells, horsts and grabens distribution. There determined the most interesting types of hydrocarbon traps connected with various tectonic forms, river and deltaic channels, bars, conturites, carbonate reefs, etc. Paleogeothermic and paleogeodynamic reconstructions allow to determine the main phases of oil and gas accumulation. The most prospective oil-gas-bearing zones and areas are mapped.

  15. Modelling of the anthropogenic tritium transient and its decay product helium-3 in the Mediterranean Sea using a high-resolution regional model

    NASA Astrophysics Data System (ADS)

    Ayache, M.; Dutay, J.-C.; Jean-Baptiste, P.; Beranger, K.; Arsouze, T.; Beuvier, J.; Palmieri, J.; Le-vu, B.; Roether, W.

    2015-05-01

    This numerical study provides the first simulation of the anthropogenic tritium invasion and its decay product helium-3 (3He) in the Mediterranean Sea. The simulation covers the entire tritium (3H) transient generated by the atmospheric nuclear weapons tests performed in the 1950s and early 1960s and is run till 2011. Tritium, helium-3 and their derived age estimates are particularly suitable for studying intermediate and deep-water ventilation and spreading of water masses at intermediate/deep levels. The simulation is made using a high-resolution regional model NEMO (Nucleus for European Modelling of the Ocean), in a regional configuration for the Mediterranean Sea called MED12, forced at the surface with prescribed tritium evolution derived from observations. The simulation is compared to measurements of tritium and helium-3 performed along large-scale transects in the Mediterranean Sea during the last few decades on cruises of R/V Meteor: M5/6, M31/1, M44/4, M51/2, M84/3, and R/V Poseidon: 234. The results show that the input function used for the tritium generates a realistic distribution of the main hydrographic features of the Mediterranean Sea circulation. In the eastern basin, the results highlight the weak formation of Adriatic Deep Water in the model, which explains its weak contribution to the Eastern Mediterranean Deep Water (EMDW) in the Ionian sub-basin. It produces a realistic representation of the Eastern Mediterranean Transient (EMT) signal, simulating a deep-water formation in the Aegean sub-basin at the beginning of 1993, with a realistic timing of deep-water renewal in the eastern basin.

  16. Assessment of impact of geochemical and environmental properties on the meiofauna (benthic foraminifer, ostracod, mollusc) assemblages: A case study in The Late Quaternary Sediments In The Gulf Of Izmir (Eastern Aegean Sea)

    NASA Astrophysics Data System (ADS)

    Yümün, Zeki Ü.

    2016-04-01

    The drilling samples collected from varying depths at 1.00-13.00 m at four different localities of Karsiyaka, Bayrakli, Inciralti and Urla (Çesmealti) in the Gulf of Izmir were studied for their geochemical, sedimantological and micropaleontological properties. The purpose of this study is to describe the meiofauna of the sediments, to determine the pollution history of the gulf and to show the effect of the pollution on the foraminifera and ostracoda. Examination of the loose sediments reveals that the gulf has been affected by the sea for a long time, and it had a rich microfaunal assemblages. Both foraminiferal tests and ostracod carapaces have coloring, and morphological abnormalities have been determined in foraminiferal tests. Peneroplis pertusus (Forskal) and P. planatus (Fichtel and Moll) have blue and black colored tests, while morphological abnormalities were observed on the tests of Ammonia compacta Hofker, Elphidium complanatum (d'Orbigny), E. crispum (Linné), E. macellum (Fichtel and Moll). The ostracod carapaces are generally gray-black colored. Heavy metal (Cr, Mn, Zn, Co, Ni, Cu) analyses have been carried out on the sediments of the Gulf of Izmir. Heavy metal concentrations are high in Bayrakli, and low in Urla (Çesmealti). Cr, Mn and Zn values are the highest in Bayrakli, whereas Co, Ni and Cu values are the highest in Inciralti. Scanning Electron Microscope (SEM) analyses were performed and no heavy metal was detected on the white and colored ostracod carapaces. When the white and colored ostracod carapaces are compared, the coloured ostracode carapace has higher Mg content, and also includes Fe, Al, N, Cl and K. Based on the results obtained, it is observed that the Bayrakli region have been more affected by the pollution than Urla (Çesmealti).

  17. On ecosystem-based regions in the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Ojaveer, Evald; Kalejs, Margers

    2008-11-01

    Maintenance of diversity of life in the sea and supporting sustainable use of marine resources require an ecosystem approach. The principles of differentiation of large geographical units on the ecosystem basis that could be applied in research and for the assessment and management of ecosystems and resources in the Baltic Sea have not been satisfactorily formulated up to now. Long-term data series collected by the authors and literature sources were used to subdivide the Baltic Sea into regional ecosystem units. Ten regions (Kattegat, Belts and the Sound, Arkona, Southwest, Eastern and Northwest of the Baltic Proper, Gulf of Riga, Gulf of Finland, Bothnian Sea, Bothnian Bay) were differentiated, some of them including sub-regions. They were grouped into three macroregions (the Transition Area, Baltic Proper and Large Gulfs). Hydrodynamic and geomorphological characters and the areas of local populations of organisms developed as a result of adaptation of species to their habitats constituted the main basis of the division. Circular cyclonic density-dependent currents in the deeps facilitate levelling of the conditions and integrate ecosystems in the regions. They are also responsible for the establishment of the regional depots of nutrients. The nutrients for the biological production are supplied mainly via the zones of intense vertical mixing (high-energy zones) to the euphotic layer. The regions differ in essential environmental conditions. In the process of adaptation to their habitats fishes (herring Clupea harengus membras, sprat Sprattus sprattus balticus, cod Gadus morhua callarias, flounder Platichthys flesus trachurus etc.) and other organisms have developed infraspecific units. The ecosystems and infraspecific units of exploited species should be assessed and managed separately if their vital parameters significantly differ from one another.

  18. Ethiopian Red Sea petroleum geology and regional geophysical evaluation

    SciTech Connect

    Assefa, A. Tadesse, K.; Worku, T.; Tsadik, E.G. )

    1991-08-01

    The World Bank-executed Red Sea/Gulf of Aden Regional Hydrocarbon Study Project was organized to synthesize data on the Red Sea and Gulf of Aden basins. The primary objectives were to encourage increased hydrocarbon exploration activity within the project area by applying recent exploration techniques basin wide, and to train national geoscientists in exploration techniques. The study of the Ethiopian Red Sea and Gulf of Aden was based on public-domain exploration data, published information, and data released by operating companies. These included reports, sections and wire lines logs from eight wells, samples from seven wells for biostratigraphic analysis, and samples from five wells for geochemical analysis. Interpretation was carried out on 6,600 line-km of seismic data selected from a grid of 29,710 line-km. Four horizons were identified on a regional basis, including the sea floor, top and near base of Middle to Upper Miocene evaporites, and approximate acoustic basement. A bathymetric map, three structure-contour maps, and three interval isopach maps were prepared using digitized picks from the interpreted seismic. The results show that the Ethiopian Red Sea is similar to the better known productive Gulf of Suez in some respects, including the overall tectonic evolution and the Miocene to Holocene stratigraphic sequence. Nevertheless, significant differences result from the location of the Ethiopian Red Sea in the transition zone to the Afar area. An important difference is the development of two major en echelon trends of rifting separated by a block with limited extension in the Danakil Alps. The resulting variations in sedimentary sequence, structural style, and geothermal gradient suggest that a favorable petroleum potential may be present locally in both pre-evaporite and post-evaporite objectives.

  19. Regional variability in sea ice melt in a changing Arctic.

    PubMed

    Perovich, Donald K; Richter-Menge, Jacqueline A

    2015-07-13

    In recent years, the Arctic sea ice cover has undergone a precipitous decline in summer extent. The sea ice mass balance integrates heat and provides insight on atmospheric and oceanic forcing. The amount of surface melt and bottom melt that occurs during the summer melt season was measured at 41 sites over the time period 1957 to 2014. There are large regional and temporal variations in both surface and bottom melting. Combined surface and bottom melt ranged from 16 to 294 cm, with a mean of 101 cm. The mean ice equivalent surface melt was 48 cm and the mean bottom melt was 53 cm. On average, surface melting decreases moving northward from the Beaufort Sea towards the North Pole; however interannual differences in atmospheric forcing can overwhelm the influence of latitude. Substantial increases in bottom melting are a major contributor to ice losses in the Beaufort Sea, due to decreases in ice concentration. In the central Arctic, surface and bottom melting demonstrate interannual variability, but show no strong temporal trends from 2000 to 2014. This suggests that under current conditions, summer melting in the central Arctic is not large enough to completely remove the sea ice cover.

  20. Regional variability in sea ice melt in a changing Arctic

    PubMed Central

    Perovich, Donald K.; Richter-Menge, Jacqueline A.

    2015-01-01

    In recent years, the Arctic sea ice cover has undergone a precipitous decline in summer extent. The sea ice mass balance integrates heat and provides insight on atmospheric and oceanic forcing. The amount of surface melt and bottom melt that occurs during the summer melt season was measured at 41 sites over the time period 1957 to 2014. There are large regional and temporal variations in both surface and bottom melting. Combined surface and bottom melt ranged from 16 to 294 cm, with a mean of 101 cm. The mean ice equivalent surface melt was 48 cm and the mean bottom melt was 53 cm. On average, surface melting decreases moving northward from the Beaufort Sea towards the North Pole; however interannual differences in atmospheric forcing can overwhelm the influence of latitude. Substantial increases in bottom melting are a major contributor to ice losses in the Beaufort Sea, due to decreases in ice concentration. In the central Arctic, surface and bottom melting demonstrate interannual variability, but show no strong temporal trends from 2000 to 2014. This suggests that under current conditions, summer melting in the central Arctic is not large enough to completely remove the sea ice cover. PMID:26032323

  1. Holocene Sea-Level Database For The Caribbean Region

    NASA Astrophysics Data System (ADS)

    Khan, N. S.; Horton, B.; Engelhart, S. E.; Peltier, W. R.; Scatena, F. N.; Vane, C. H.; Liu, S.

    2013-12-01

    Holocene relative sea-level (RSL) records from far-field locations are important for understanding the driving mechanisms controlling the nature and timing of the mid-late Holocene reduction in global meltwaters and providing background rates of late Holocene RSL change with which to compare the magnitude of 20th century RSL rise. The Caribbean region has traditionally been considered far-field (i.e., with negligible glacio-isostatic adjustment (GIA) influence), although recent investigations indicate otherwise. Here, we consider the spatial variability in glacio-isostatic, tectonic and local contributions on RSL records from the circum-Caribbean region to infer a Holocene eustatic sea-level signal. We have constructed a database of quality-controlled, spatially comprehensive, Holocene RSL observations for the circum-Caribbean region. The database contains over 500 index points, which locate the position of RSL in time and space. The database incorporates sea-level observations from a latitudinal range of 5°N to 25°N and longitudinal range of 55°W to 90°W. We include sea-level observations from 11 ka BP to present, although the majority of the index points in the database are younger than 8 ka BP. The database is sub-divided into 13 regions based on the distance from the former Laurentide Ice Sheet and regional tectonic setting. The index points were primarily derived from mangrove peat deposits, which in the Caribbean form in the upper half of the tidal range, and corals (predominantly Acropora palmata), the growth of which is constrained to the upper 5 m of water depth. The index points are classified on the basis of their susceptibility to compaction (e.g., intercalated, basal). The influence of temporal changes in tidal range on index points is also considered. The sea-level reconstructions demonstrate that RSL did not exceed the present height (0 m) during the Holocene in the majority of locations, except at sites in Suriname/Guayana and possibly Trinidad

  2. Impact of Diurnal Warming on Assimilation of Satellite Observations of Sea Surface Temperature

    DTIC Science & Technology

    2014-09-09

    insolation in the southeast, and conditions can be significantly cooler to the north in the Aegean Sea, a region exposed to cold continental wind...independent SST observations from drifting buoys. While all in situ surface-only observations are withheld from the assimilative model forecasts and...Other, similarly withheld surface in-situ observations such as those from fixed buoy locations or shipboard observations might be used, but the drifting

  3. Setting Priorities for Regional Conservation Planning in the Mediterranean Sea

    PubMed Central

    Micheli, Fiorenza; Levin, Noam; Giakoumi, Sylvaine; Katsanevakis, Stelios; Abdulla, Ameer; Coll, Marta; Fraschetti, Simonetta; Kark, Salit; Koutsoubas, Drosos; Mackelworth, Peter; Maiorano, Luigi; Possingham, Hugh P.

    2013-01-01

    Spatial prioritization in conservation is required to direct limited resources to where actions are most urgently needed and most likely to produce effective conservation outcomes. In an effort to advance the protection of a highly threatened hotspot of marine biodiversity, the Mediterranean Sea, multiple spatial conservation plans have been developed in recent years. Here, we review and integrate these different plans with the goal of identifying priority conservation areas that represent the current consensus among the different initiatives. A review of six existing and twelve proposed conservation initiatives highlights gaps in conservation and management planning, particularly within the southern and eastern regions of the Mediterranean and for offshore and deep sea habitats. The eighteen initiatives vary substantially in their extent (covering 0.1–58.5% of the Mediterranean Sea) and in the location of additional proposed conservation and management areas. Differences in the criteria, approaches and data used explain such variation. Despite the diversity among proposals, our analyses identified ten areas, encompassing 10% of the Mediterranean Sea, that are consistently identified among the existing proposals, with an additional 10% selected by at least five proposals. These areas represent top priorities for immediate conservation action. Despite the plethora of initiatives, major challenges face Mediterranean biodiversity and conservation. These include the need for spatial prioritization within a comprehensive framework for regional conservation planning, the acquisition of additional information from data-poor areas, species or habitats, and addressing the challenges of establishing transboundary governance and collaboration in socially, culturally and politically complex conditions. Collective prioritised action, not new conservation plans, is needed for the north, western, and high seas of the Mediterranean, while developing initial information

  4. Setting priorities for regional conservation planning in the Mediterranean Sea.

    PubMed

    Micheli, Fiorenza; Levin, Noam; Giakoumi, Sylvaine; Katsanevakis, Stelios; Abdulla, Ameer; Coll, Marta; Fraschetti, Simonetta; Kark, Salit; Koutsoubas, Drosos; Mackelworth, Peter; Maiorano, Luigi; Possingham, Hugh P

    2013-01-01

    Spatial prioritization in conservation is required to direct limited resources to where actions are most urgently needed and most likely to produce effective conservation outcomes. In an effort to advance the protection of a highly threatened hotspot of marine biodiversity, the Mediterranean Sea, multiple spatial conservation plans have been developed in recent years. Here, we review and integrate these different plans with the goal of identifying priority conservation areas that represent the current consensus among the different initiatives. A review of six existing and twelve proposed conservation initiatives highlights gaps in conservation and management planning, particularly within the southern and eastern regions of the Mediterranean and for offshore and deep sea habitats. The eighteen initiatives vary substantially in their extent (covering 0.1-58.5% of the Mediterranean Sea) and in the location of additional proposed conservation and management areas. Differences in the criteria, approaches and data used explain such variation. Despite the diversity among proposals, our analyses identified ten areas, encompassing 10% of the Mediterranean Sea, that are consistently identified among the existing proposals, with an additional 10% selected by at least five proposals. These areas represent top priorities for immediate conservation action. Despite the plethora of initiatives, major challenges face Mediterranean biodiversity and conservation. These include the need for spatial prioritization within a comprehensive framework for regional conservation planning, the acquisition of additional information from data-poor areas, species or habitats, and addressing the challenges of establishing transboundary governance and collaboration in socially, culturally and politically complex conditions. Collective prioritised action, not new conservation plans, is needed for the north, western, and high seas of the Mediterranean, while developing initial information-based plans

  5. Geodynamics of the Gibraltar Arc and the Alboran Sea region

    NASA Astrophysics Data System (ADS)

    Corsini, M.; Chalouan, A.; Galindo-Zaldivar, J.

    2014-07-01

    Located at the Westernmost tip of the Mediterranean sea, the Gibraltar Arc is a very complex zone. The Betics in Spain and the Rif belt in Morocco surround the Alboran sea characterized by a thinned continental crust. The geodynamic evolution of this region results from the convergence of African and Iberian margins since the Late Cretaceous. It is controlled both by plate convergence and mantle dynamics, which significantly impact on morphology, sedimentary environments, tectonics, metamorphism and magmatism. We present here the contents of the special issue on the Gibraltar Arc and nearby regions, following the workshop organized at the University Abdelmalek Essaadi of Tetouan in Morocco from 27 to 28 October, 2011. The goal of this international workshop was to have an overview of the actual advance in research concerning the Rif and Betics chains, the Alboran basin, and their influence on the Iberian and African forelands.

  6. Sub-Regional Sea Ice Preferences of Pacific Walrus in the Bering Sea Using SAR Data

    NASA Astrophysics Data System (ADS)

    Sacco, A.; Mahoney, A. R.; Eicken, H.; Johnson, M. A.; Ray, C.

    2014-12-01

    The Pacific walrus (O. r. divergens) uses winter sea ice in the Bering Sea for numerous parts of its natural history including courtship, foraging, and migration. Recent and predicted loss of sea ice has caused the Pacific walrus to be considered for an elevated status under the Endangered Species Act. Study of the ice conditions during this period is required to investigate changes in the Bering Sea ice pack and its effects on walrus sustainability. Using Radarsat-1 data and second-order texture statistics, a classification system was devised to separate sea ice into three distinguishable classes based on walrus needs of open water availability in the pack ice: discontinuous pack ice, continuous pack ice, and open water. Classifications are performed on sub-regional image areas to facilitate classification of heterogeneous seascapes which are thought to be distinguishable by walrus. Spatial, as well as temporal, changes in the seascape cover, based on the classification, are achieved. These results are then combined with ship-based observations of walrus to quantify walrus habitat preference. The three-class algorithm has a success rate of 94% for the discontinuous ice and continuous pack ice. Radarsat-1 images from 2004 - 2008 were analyzed for changes in seasonal and annual discontinuous ice extent. After classification, the spatial extent of discontinuous ice was found to vary throughout 2004 - 2008 in the Bering Sea shelf. Walrus are also shown to prefer discontinuous pack far from the southernmost ice edge. Maps of walrus habitat preference and persistent areas of sea ice seascapes are created and then can be used for the walrus' status consideration under the Endangered Species Act in addition to general species management issues.

  7. Regional magnetic fields as navigational markers for sea turtles.

    PubMed

    Lohmann, K J; Cain, S D; Dodge, S A; Lohmann, C M

    2001-10-12

    Young loggerhead sea turtles (Caretta caretta) from eastern Florida undertake a transoceanic migration in which they gradually circle the north Atlantic Ocean before returning to the North American coast. Here we report that hatchling loggerheads, when exposed to magnetic fields replicating those found in three widely separated oceanic regions, responded by swimming in directions that would, in each case, help keep turtles within the currents of the North Atlantic gyre and facilitate movement along the migratory pathway. These results imply that young loggerheads have a guidance system in which regional magnetic fields function as navigational markers and elicit changes in swimming direction at crucial geographic boundaries.

  8. Attributing extreme precipitation in the Black Sea region to sea surface warming

    NASA Astrophysics Data System (ADS)

    Meredith, Edmund; Semenov, Vladimir; Maraun, Douglas; Park, Wonsun; Chernokulsky, Alexander

    2016-04-01

    Higher sea surface temperatures (SSTs) warm and moisten the overlying atmosphere, increasing the low-level atmospheric instability, the moisture available to precipitating systems and, hence, the potential for intense convective systems. Both the Mediterranean and Black Sea regions have seen a steady increase in summertime SSTs since the early 1980s, by over 2 K in places. This raises the question of how this SST increase has affected convective precipitation extremes in the region, and through which mechanisms any effects are manifested. In particular, the Black Sea town of Krymsk suffered an unprecedented precipitation extreme in July 2012, which may have been influenced by Black Sea warming, causing over 170 deaths. To address this question, we adopt two distinct modelling approaches to event attribution and compare their relative merits. In the first, we use the traditional probabilistic event attribution approach involving global climate model ensembles representative of the present and a counterfactual past climate where regional SSTs have not increased. In the second, we use the conditional event attribution approach, taking the 2012 Krymsk precipitation extreme as a showcase example. Under the second approach, we carry out ensemble sensitivity experiments of the Krymsk event at convection-permitting resolution with the WRF regional model, and test the sensitivity of the event to a range of SST forcings. Both experiments show the crucial role of recent Black Sea warming in amplifying the 2012 Krymsk precipitation extreme. In the conditional event attribution approach, though, the explicit simulation of convective processes provides detailed insight into the physical mechanisms behind the extremeness of the event, revealing the dominant role of dynamical (i.e. static stability and vertical motions) over thermodynamical (i.e. increased atmospheric moisture) changes. Additionally, the wide range of SST states tested in the regional setup, which would be

  9. The fate of gas hydrates in the Barents Sea and Kara Sea region

    NASA Astrophysics Data System (ADS)

    Klitzke, Peter; Scheck-Wenderoth, Magdalena; Schicks, Judith; Luzi-Helbing, Manja; Cacace, Mauro; Jacquey, Antoine; Sippel, Judith; Faleide, Jan Inge

    2016-04-01

    The Barents Sea and Kara Sea are located in the European Arctic. Recent seismic lines indicate the presence of gas hydrates in the Barents Sea and Kara Sea region. Natural gas hydrates contain huge amounts of methane. Their stability is mainly sensitive to pressure and temperature conditions which make them susceptible for climate change. When not stable, large volumes of methane will be released in the water column and - depending on the water depth - may also be released into the atmosphere. Therefore, studying the evolution in time and space of the gas hydrates stability zone in the Barents Sea region is of interest for both environmental impact and energy production. In this study, we assess the gas hydrate inventory of the Barents Sea and Kara Sea under the light of increasing ocean bottom temperatures in the next 200 years. Thereby, we make use of an existing 3D structural and thermal model which resolves five sedimentary units, the crystalline crust and the lithospheric mantle. The sedimentary units are characterised by the prevailing lithology and porosity including effects of post-depositional erosion which strongly affect the local geothermal gradient. Governing equations for the conductive 3D thermal field and momentum balance have been integrated in a massively parallel finite-element-method based framework (MOOSE). The MOOSE framework provides a powerful and flexible platform to solve multiphysics problems implicitly on unstructured meshes. First we calculate the present-day steady-state 3D thermal field. Subsequently, we use the latter as initial condition to calculate the transient 3D thermal field for the next 200 years considering an ocean temperature model as upper boundary. Temperature and load distributions are then used to calculate the thickness of the gas hydrate stability zone for each time step. The results show that the gas hydrate stability zone strongly varies in the region due to the local geothermal gradient changes. The latter

  10. Study of sea ice regions using AltiKa measurements

    NASA Astrophysics Data System (ADS)

    Poisson, Jean-Christophe; Thibaut, Pierre; Hoang, Duc; Boy, François; Guillot, Amandine; Picot, Nicolas

    2015-04-01

    Since the launch of the SARAL/AltiKa mission on February 25th, 2013, altimeter measurements of excellent quality are acquired all over the globe for the first time in Ka-band. One of the main benefits of the Ka-band is to have a very low penetration length in the ice (unlike the Ku-band historically used by previous altimetry missions), which allows to significantly reduce measurements uncertainties of the sea ice topography. Flying on the Envisat orbit and providing measurements at 40 Hz, the exploitation of AltiKa waveforms on sea ice is of great interest. Sea ice covered regions are characterized by a large number of different surfaces with a multitude of backscattering properties rapidly evolving with time. Thanks to the high resolution and precision of the AltiKa measurements, backscattering properties from each of these surfaces (first year ice, multiyear ice, fast ice, leads, polynyas, etc. …) can be observed through rapid changes of the returned echo shape. In the framework of the PEACHI project (Prototype for Expertise on AltiKa, for Coastal, Hydrology and Ice funded by CNES) which aims at analyzing and improving AltiKa measurements, a waveform processing based on an altimeter echo classification is developed and performed on all available AltiKa data in the Arctic ocean. Through this processing a study is conducted on the the evolution of the sea ice cover observed in Ka-band.

  11. Divergent patterns of recent sea ice cover across the Bering, Chukchi, and Beaufort seas of the Pacific Arctic Region

    NASA Astrophysics Data System (ADS)

    Frey, Karen E.; Moore, G. W. K.; Cooper, Lee W.; Grebmeier, Jacqueline M.

    2015-08-01

    Over the past three decades of the observed satellite record, there have been significant changes in sea ice cover across the Bering, Chukchi, and Beaufort seas of the Pacific Arctic Region (PAR). Satellite data reveal that patterns in sea ice cover have been spatially heterogeneous, with significant declines in the Chukchi and Beaufort seas, yet more complex multi-year variability in the Bering Sea south of St. Lawrence Island. These patterns in the Chukchi and Beaufort seas have intensified since 2000, indicating a regime shift in sea ice cover across the northern portion of the PAR. In particular, satellite data over 1979-2012 reveal localized decreases in sea ice presence of up to -1.64 days/year (Canada Basin) and -1.24 days/year (Beaufort Sea), which accelerated to up to -6.57 days/year (Canada Basin) and -12.84 days/year (Beaufort Sea) over the 2000-2012 time period. In contrast, sea ice in the Bering Sea shows more complex multi-year variability with localized increases in sea ice presence of up to +8.41 days/year since 2000. The observed increases in sea ice cover since 2000 in the southern Bering Sea shelf region are observed in wintertime, whereas sea ice losses in the Canada Basin and Beaufort Sea have occurred during summer. We further compare sea ice variability across the region with the National Centers for Environmental Prediction (NCEP) North American Regional Reanalysis (NARR) wind and air temperature fields to determine the extent to which this recent variability is driven by thermal vs. wind-driven processes. Results suggest that for these localized areas that are experiencing the most rapid shifts in sea ice cover, those in the Beaufort Sea are primarily wind driven, those offshore in the Canada Basin are primarily thermally driven, and those in the Bering Sea are influenced by elements of both. Sea ice variability (and its drivers) across the PAR provides critical insight into the forcing effects of recent shifts in climate and its likely

  12. Recent Seismicity and Deformation Patterns in the Ionian Sea region

    NASA Astrophysics Data System (ADS)

    Chouliaras, Gerasimos; Chousianitis, Konstantinos; Drakatos, Georgios; Makropoulos, Konstantinos

    2013-04-01

    The Ionian Sea, between the Calabrian and Hellenic Arcs, is a the most seismically active area in Europe due to the active collision and subduction processes that involve the African and Eurasian plates. Many large and catastrophic earthquakes have occurred along the western coasts of Greece and offshore in the Ionian islands throughout history, however it was following the 'Great Ionian Earthquake', which struck the southern Ionian islands on August 12th, 1953, that a Wood-Anderson seismograph was installed on the island of Kefalonia by the National Observatory of Athens (NOA). Subsequently, the NOA seismographic network expanded and improved with new station installations and standard observatory practice, in order to produce detailed monthly bulletins and a homogeneous and complete earthquake catalog. During the last five years and in order to further improve the assessment of the tectonic stress field and the seismic hazard of the Ionian Sea region, NOA established six permanent GPS stations on the islands and in Western Greece, all transmitting real-time data. In this study we determine and map: a) the spatial and temporal seismicity rate changes, b) the tectonic stress field associated with the recent seismicity and c) the GPS deformation patterns, of the Ionian Sea region. From this multi-parameter approach, the results converge to indicate that advances or retardations of the seismicity follow the patterns of stress increase and decrease as predicted by the Coulomb hypothesis.

  13. Air-sea exchange over Black Sea estimated from high resolution regional climate simulations

    NASA Astrophysics Data System (ADS)

    Velea, Liliana; Bojariu, Roxana; Cica, Roxana

    2013-04-01

    Black Sea is an important influencing factor for the climate of bordering countries, showing cyclogenetic activity (Trigo et al, 1999) and influencing Mediterranean cyclones passing over. As for other seas, standard observations of the atmosphere are limited in time and space and available observation-based estimations of air-sea exchange terms present quite large ranges of uncertainty. The reanalysis datasets (e.g. ERA produced by ECMWF) provide promising validation estimates of climatic characteristics against the ones in available climatic data (Schrum et al, 2001), while cannot reproduce some local features due to relatively coarse horizontal resolution. Detailed and realistic information on smaller-scale processes are foreseen to be provided by regional climate models, due to continuous improvements of physical parameterizations and numerical solutions and thus affording simulations at high spatial resolution. The aim of the study is to assess the potential of three regional climate models in reproducing known climatological characteristics of air-sea exchange over Black Sea, as well as to explore the added value of the model compared to the input (reanalysis) data. We employ results of long-term (1961-2000) simulations performed within ENSEMBLE project (http://ensemblesrt3.dmi.dk/) using models ETHZ-CLM, CNRM-ALADIN, METO-HadCM, for which the integration domain covers the whole area of interest. The analysis is performed for the entire basin for several variables entering the heat and water budget terms and available as direct output from the models, at seasonal and annual scale. A comparison with independent data (ERA-INTERIM) and findings from other studies (e.g. Schrum et al, 2001) is also presented. References: Schrum, C., Staneva, J., Stanev, E. and Ozsoy, E., 2001: Air-sea exchange in the Black Sea estimated from atmospheric analysis for the period 1979-1993, J. Marine Systems, 31, 3-19 Trigo, I. F., T. D. Davies, and G. R. Bigg (1999): Objective

  14. Earthquake Scenario-Based Tsunami Wave Heights in the Eastern Mediterranean and Connected Seas

    NASA Astrophysics Data System (ADS)

    Necmioglu, Ocal; Özel, Nurcan Meral

    2015-12-01

    We identified a set of tsunami scenario input parameters in a 0.5° × 0.5° uniformly gridded area in the Eastern Mediterranean, Aegean (both for shallow- and intermediate-depth earthquakes) and Black Seas (only shallow earthquakes) and calculated tsunami scenarios using the SWAN-Joint Research Centre (SWAN-JRC) code ( Mader 2004; Annunziato 2007) with 2-arcmin resolution bathymetry data for the range of 6.5—Mwmax with an Mw increment of 0.1 at each grid in order to realize a comprehensive analysis of tsunami wave heights from earthquakes originating in the region. We defined characteristic earthquake source parameters from a compiled set of sources such as existing moment tensor catalogues and various reference studies, together with the Mwmax assigned in the literature, where possible. Results from 2,415 scenarios show that in the Eastern Mediterranean and its connected seas (Aegean and Black Sea), shallow earthquakes with Mw ≥ 6.5 may result in coastal wave heights of 0.5 m, whereas the same wave height would be expected only from intermediate-depth earthquakes with Mw ≥ 7.0 . The distribution of maximum wave heights calculated indicate that tsunami wave heights up to 1 m could be expected in the northern Aegean, whereas in the Black Sea, Cyprus, Levantine coasts, northern Libya, eastern Sicily, southern Italy, and western Greece, up to 3-m wave height could be possible. Crete, the southern Aegean, and the area between northeast Libya and Alexandria (Egypt) is prone to maximum tsunami wave heights of >3 m. Considering that calculations are performed at a minimum bathymetry depth of 20 m, these wave heights may, according to Green's Law, be amplified by a factor of 2 at the coastline. The study can provide a basis for detailed tsunami hazard studies in the region.

  15. Changes in extreme regional sea level under global warming

    NASA Astrophysics Data System (ADS)

    Brunnabend, S.-E.; Dijkstra, H. A.; Kliphuis, M. A.; Bal, H. E.; Seinstra, F.; van Werkhoven, B.; Maassen, J.; van Meersbergen, M.

    2017-01-01

    An important contribution to future changes in regional sea level extremes is due to the changes in intrinsic ocean variability, in particular ocean eddies. Here, we study a scenario of future dynamic sea level (DSL) extremes using a high-resolution version of the Parallel Ocean Program and generalized extreme value theory. This model is forced with atmospheric fluxes from a coupled climate model which has been integrated under the IPCC-SRES-A1B scenario over the period 2000-2100. Changes in 10-year return time DSL extremes are very inhomogeneous over the globe and are related to changes in ocean currents and corresponding regional shifts in ocean eddy pathways. In this scenario, several regions in the North Atlantic experience an increase in mean DSL of up to 0.4 m over the period 2000-2100. DSL extremes with a 10-year return time increase up to 0.2 m with largest values in the northern and eastern Atlantic.

  16. Regional Ocean Colour Remote Sensing Algorithm for the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Hieronymi, Martin; Muller, Dagmar; Krasemann, Hajo; Schonfeld, Wolfgang; Rottgers, Rudiger; Doerffer, Roland

    2015-12-01

    The Baltic Sea is a challenging study site from an optically point of view. Its partly highly absorbing waters are mainly associated with the presence of coloured dissolved organic matter and often accompanied by non-algae absorbing particles. In addition, the Baltic Sea area is characterised by massive annual surface blooms of cyanobacteria. In Europe, the Baltic Sea is a very specific and important case study with intense user interest. In the framework of different research projects as the “Ocean Colour Climate Change Initiative”, the “SEOM OC Extreme Case 2 Waters”, and partly “MyOcean”, we aim to develop an optimised, error-characterised, regional ocean colour processor applicable to several satellite sensors, like MODIS, MERIS, VIIRS, and OLCI. The procedure, which is used to determine inherent optical properties and different water constituents’ concentrations from remote sensing reflectance, is an artificial Neural Network (NN). We provide first results of comparisons of in-situ data with different ocean colour products.

  17. 15 CFR 918.6 - Duration of Sea Grant Regional Consortium designation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Consortium designation. 918.6 Section 918.6 Commerce and Foreign Trade Regulations Relating to Commerce and... REGULATIONS SEA GRANTS § 918.6 Duration of Sea Grant Regional Consortium designation. Designation will be made... consistent with the goals of the Act. Continuation of the Sea Grant Regional Consortium designation...

  18. 15 CFR 918.6 - Duration of Sea Grant Regional Consortium designation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Consortium designation. 918.6 Section 918.6 Commerce and Foreign Trade Regulations Relating to Commerce and... REGULATIONS SEA GRANTS § 918.6 Duration of Sea Grant Regional Consortium designation. Designation will be made... consistent with the goals of the Act. Continuation of the Sea Grant Regional Consortium designation...

  19. 15 CFR 918.6 - Duration of Sea Grant Regional Consortium designation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Consortium designation. 918.6 Section 918.6 Commerce and Foreign Trade Regulations Relating to Commerce and... REGULATIONS SEA GRANTS § 918.6 Duration of Sea Grant Regional Consortium designation. Designation will be made... consistent with the goals of the Act. Continuation of the Sea Grant Regional Consortium designation...

  20. 15 CFR 918.6 - Duration of Sea Grant Regional Consortium designation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Consortium designation. 918.6 Section 918.6 Commerce and Foreign Trade Regulations Relating to Commerce and... REGULATIONS SEA GRANTS § 918.6 Duration of Sea Grant Regional Consortium designation. Designation will be made... consistent with the goals of the Act. Continuation of the Sea Grant Regional Consortium designation...

  1. 15 CFR 918.6 - Duration of Sea Grant Regional Consortium designation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Consortium designation. 918.6 Section 918.6 Commerce and Foreign Trade Regulations Relating to Commerce and... REGULATIONS SEA GRANTS § 918.6 Duration of Sea Grant Regional Consortium designation. Designation will be made... consistent with the goals of the Act. Continuation of the Sea Grant Regional Consortium designation...

  2. Modelling of the anthropogenic tritium transient and its decay product helium-3 in the Mediterranean Sea using a high-resolution regional model

    NASA Astrophysics Data System (ADS)

    Ayache, M.; Dutay, J.-C.; Jean-Baptiste, P.; Beranger, K.; Arsouze, T.; Beuvier, J.; Palmieri, J.; Le-vu, B.; Roether, W.

    2014-12-01

    This numerical study provides the first simulation of the anthropogenic tritium invasion and its decay product helium-3 (3He) in the Mediterranean Sea. The simulation covers the entire tritium (3H) transient generated by the atmospheric nuclear-weapon tests performed in the 1950s and early 1960s and run till 2011. Tritium, helium-3 and their derived age estimates are particularly suitable for studying intermediate and deep-water ventilation and spreading of water masses at intermediate/deep levels. The simulation is made using a high resolution regional model NEMO-MED12 forced at the surface with prescribed tritium evolution derived from observations. The simulation is compared to measurements of tritium and helium-3 performed along large-scale transects in the Mediterranean Sea during the last few decades on cruises of Meteor M5/6, M31/1, M44/4, M51/2, M84/3, and Poseidon 234. The results show that the input function used for the tritium, generates a realistic distribution of the main hydrographic features of the Mediterranean Sea circulation. In the eastern basin, the results highlight the weak formation of Adriatic Deep Water in the model, which explains its weak contribution to the Eastern Mediterranean Deep Water in the Ionian sub-basin. It produces a realistic representation of the Eastern Mediterranean Transient signal, simulating a deep-water formation in the Aegean sub-basin at the beginning of the 1993, with a realistic timing of deep-water renewal in the eastern basin. In the western basin, the unusual intense deep convection event of winter 2005 in the Gulf of Lions during the Western Mediterranean Transition is simulated. However the spreading of the recently ventilated deep water toward the South is too weak. The ventilation and spreading of the Levantine Intermediate Water from the eastern basin toward the western basin is simulated with realistic tracer-age distribution compared to observation-based estimates.

  3. Moho depth and crustal thinning in the Marmara Sea region from gravity data inversion

    NASA Astrophysics Data System (ADS)

    Kende, Julia; Henry, Pierre; Bayrakci, Gaye; Özeren, Sinan; Grall, Céline

    2016-04-01

    With a width comparable to the brittle crust thickness, the Sea of Marmara strike-slip basin appears as an intermediate case between two much studied end-member cases of basin-width-to-brittle-crust-thickness ratio: the Dead Sea and the Death Valley. But geophysical studies have shown evidences of at least 5 km of mantle uplift under the Marmara Sea, much larger than in the two other cases. We compiled data from reflection, refraction and tomography seismic studies to correct satellite and survey vessel gravity data (acquired during MARSITE cruise of Ifremer R/V Pourquoi Pas ?) from the effect of topography and sedimentary basins. Assuming that no other crustal mass heterogeneity affects the gravity measurement, we inverted the residual, with constraints from seismic studies, to calculate the topography of the Moho. The 3D model obtained shows a mantle uplift broadly correlated with the Marmara deep basins, but the crustal thinning spreads southward further than the basin limits, This is explained by ductile flow in the lower crust between a northern zone where the thinning is closely related to the Marmara Fault strike-slip basins and a southern zone where extension appears associated with older crustal detachment systems. Finally, we estimated the extension budget in the area during the Marmara Sea formation by comparing our 3D crust volume with an initial crust of constant thickness. The increase in surface area, 2100±300 km2, is compatible with present day GPS velocity field measurement assuming steady state and an initiation of extension in the area about 5 Myr ago. We conclude that although the zone went through tectonic reorganizations during the Pliocene as the North Anatolian Fault system propagated westward, the overall extension rate in the area could have been stable, or decreasing with time, and thus should be understood in a broader geodynamic framework comprising the Aegean subduction.

  4. Regional diversity of amphipoda in the Caribbean Sea.

    PubMed

    Martín, Alberto; Díaz, Yusbelly; Miloslavich, Patricia; Escobar-Briones, Elva; Guerra-García, José Manuel; Ortiz, Manuel; Valencia, Bellineth; Giraldo, Alan; Klein, Eduardo

    2013-12-01

    The order Amphipoda is one of the most diverse within Peracarids, and comprises 6950 described marine species. Amphipod research in the Caribbean Sea began in the late 1800s, but has increased significantly since 1980. In this study, we analized the amphipod biodiversity (Caprellidea, Gammaridea, Hyperiidea, and Ingolfiellidea) of the Caribbean Sea. For this, we compiled available data on species diversity of marine amphipods (data bases: WoRMS and OBIS and published species lists) into a comprehensive taxonomic list by country for the ecoregions of the Caribbean. Additionally, we analized the relative contribution of each country to regional diversity and the rate of discovery of new species. The Caribbean amphipod fauna is composed of 535 species within 236 genera and 73 families for the higher taxon. The Western Caribbean ecoregion holds the largest diversity (282 species), while the Eastern Caribbean recorded the lowest one (73). Mexico and Venezuela recorded the largest number of species with 266 and 206, respectively. Twelve countries had less than 50 species. The richest suborder is the Gammaridea with 381 species followed by the suborder Hyperiidea with 116. From the total of 535 amphipod species reported for the Caribbean region, 218 have the Caribbean as the holotype locality, and 132 are endemic (about 25% of the total). Areas of higher diversity seem to be concentrated along the Mexican Caribbean, Cuba and the Northern coast of South America (Venezuela-Colombia); however, such pattern is most likely reflecting local collection efforts and taxonomic expertise rather than actual distribution. Knowledge of amphipod species is mostly limited to shallow, near-shore waters, with little infonnation available on the deep sea fauna. Regional research priorities for this group should be focused on completing shallow water coastal inventories of species in Central America and the Greater and Lesser Antilles. In addition, sampling the deep sea ecosystems should

  5. Evolutionary processes in a continental island system: molecular phylogeography of the Aegean Nigella arvensis alliance (Ranunculaceae) inferred from chloroplast DNA.

    PubMed

    Bittkau, C; Comes, H P

    2005-11-01

    Continental shelf island systems, created by rising sea levels, provide a premier setting for studying the effects of past fragmentation, dispersal, and genetic drift on taxon diversification. We used phylogeographical (nested clade) and population genetic analyses to elucidate the relative roles of these processes in the evolutionary history of the Aegean Nigella arvensis alliance (= 'coenospecies'). We surveyed chloroplast DNA (cpDNA) variation in 455 individuals from 47 populations (nine taxa) of the alliance throughout its core range in the Aegean Archipelago and surrounding mainland areas of Greece and Turkey. The study revealed the presence of three major lineages, with largely nonoverlapping distributions in the Western, Central, and Eastern Aegean. There is evidence supporting the idea that these major lineages evolved in situ from a widespread (pan-Aegean) ancestral stock as a result of multiple fragmentation events, possibly due to the influence of post-Messinian sea flooding, Pleistocene eustatic changes and corresponding climate fluctuations. Over-sea dispersal and founder events appear to have played a rather insignificant role in the group's history. Rather, all analytical approaches identified the alliance as an organism group with poor seed dispersal capabilities and a susceptibility to genetic drift. In particular, we inferred that the observed level of cpDNA differentiation between Kikladian island populations of Nigella degenii largely reflects population history, (viz. Holocene island fragmentation) and genetic drift in the near absence of seed flow since their time of common ancestry. Overall, our cpDNA data for the N. arvensis alliance in general, and N. degenii in particular, indicate that historical events were important in determining the phylogeographical patterns seen, and that genetic drift has historically been relatively more influential on population structure than has cytoplasmic gene flow.

  6. 76 FR 3089 - Proposed Information Collection; Comment Request; Alaska Region Bering Sea & Aleutian Islands...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-19

    ... Region Bering Sea & Aleutian Islands Crab Permits AGENCY: National Oceanic and Atmospheric Administration... of a currently approved collection. The Crab Rationalization Program allocates Bering Sea and Aleutian Islands (BSAI) crab resources among harvesters, processors, and coastal communities through...

  7. 76 FR 3090 - Proposed Information Collection; Comment Request; Alaska Region; Bering Sea and Aleutian Islands...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-19

    ... Region; Bering Sea and Aleutian Islands Crab Arbitration AGENCY: National Oceanic and Atmospheric... extension of a currently approved collection. The Crab Rationalization Program allocates Bering Sea and Aleutian Islands (BSAI) crab resources among harvesters, processors, and coastal communities through...

  8. Regional High-resolution Coupled Atmosphere Ocean Modelling in the North Sea Region

    NASA Astrophysics Data System (ADS)

    Dumenil-Gates, Lydia; Bülow, Katharina; Ganske, Anette; Heinrich, Hartmut; Klein, Birgit; Klein, Holger; Möller, Jens; Rosenhagen, Gudrun; Schade, Nils; Hüttl-Kabus, Sabine; Tinz, Birger

    2015-04-01

    The analysis of climate projections in the North Sea area is one of the research tasks of the research programme KLIWAS of the German Federal Ministry of Transport and Digital Infrastructure. A multi-model ensemble of three coupled regional atmosphere-ocean models was set up comprising very high resolution simulations for the German coastal regions of the North Sea and the Baltic to represent the complex land-sea-atmosphere conditions in the region. The ensemble consists of simulations made in cooperation with the Swedish Meteorological and Hydrological Institute, the Climate Service Centre and the Max-Planck-Institute for the period of 1950 to 2100. The KLIWAS project thereby adds coupled models to the band-width of possible future climate conditions in the atmosphere as given by the ENSEMBLES project, which were also analyzed. The coupled results are evaluated for present-day climate using a North Sea climatology of maritime conditions at a matching high resolution. In the future climate, while air and water temperatures will rise to the year 2100, the mean wind speed does not show a significant trend, but large decadal variability. The frequency of occurrence of westerly wind directions increases in the majority of simulations and results in an increase of significant wave height in the eastern parts of the North Sea. In an interdisciplinary approach, these results are used to provide regional to local information for the development of adaptation strategies for the estuary, and climate-proofing of infrastructure in the wider context of the project.

  9. Revisiting the insect mitochondrial molecular clock: the mid-Aegean trench calibration.

    PubMed

    Papadopoulou, Anna; Anastasiou, Ioannis; Vogler, Alfried P

    2010-07-01

    Phylogenetic trees in insects are frequently dated by applying a "standard" mitochondrial DNA (mtDNA) clock estimated at 2.3% My(-1), but despite its wide use reliable calibration points have been lacking. Here, we used a well-established biogeographic barrier, the mid-Aegean trench separating the western and eastern Aegean archipelago, to estimate substitution rates in tenebrionid beetles. Cytochrome oxidase I (cox1) for six codistributed genera across 28 islands (444 individuals) on both sides of the mid-Aegean trench revealed 60 independently coalescing entities delimited with a mixed Yule-coalescent model. One representative per entity was used for phylogenetic analysis of mitochondrial (cox1, 16S rRNA) and nuclear (Mp20, 28S rRNA) genes. Six nodes marked geographically congruent east-west splits whose separation was largely contemporaneous and likely to reflect the formation of the mid-Aegean trench at 9-12 Mya. Based on these "known" dates, a divergence rate of 3.54% My(-1) for the cox1 gene (2.69% when combined with the 16S rRNA gene) was obtained under the preferred partitioning scheme and substitution model selected using Bayes factors. An extensive survey suggests that discrepancies in mtDNA substitution rates in the entomological literature can be attributed to the use of different substitution models, the use of different mitochondrial gene regions, mixing of intraspecific with interspecific data, and not accounting for variance in coalescent times or postseparation gene flow. Different treatments of these factors in the literature confound estimates of mtDNA substitution rates in opposing directions and obscure lineage-specific differences in rates when comparing data from various sources.

  10. Shallow Drilling In The Salton Sea Region, The Thermal Anomaly

    SciTech Connect

    Newmark, R. L.; Kasameyer, P. W.; Younker, L. W.

    1987-01-01

    During two shallow thermal drilling programs, thermal measurements were obtained in 56 shallow (76.2 m) and one intermediate (457.3 m) depth holes located both onshore and offshore along the southern margin of the Salton Sea in the Imperial Valley, California. These data complete the surficial coverage of the thermal anomaly, revealing the shape and lateral extent of the hydrothermal system. The thermal data show the region of high thermal gradients to extend only a short distance offshore to the north of the Quaternary volcanic domes which are exposed along the southern shore of the Salton Sea. The thermal anomaly has an arcuate shape, about 4 km wide and 12 km long. Across the center of the anomaly, the transition zone between locations exhibiting high thermal gradients and those exhibiting regional thermal gradients is quite narrow. Thermal gradients rise from near regional (0.09 C/m) to extreme (0.83 C/m) in only 2.4 km. The heat flow in the central part of the anomaly is >600 mW/m{sup 2} and in some areas exceeds 1200 mW/m{sup 2}. The shape of the thermal anomaly is asymmetric with respect to the line of volcanoes previously thought to represent the center of the field, with its center line offset south of the volcanic buttes. There is no broad thermal anomaly associated with the magnetic high that extends offshore to the northeast from the volcanic domes. These observations of the thermal anomaly provide important constraints for models of the circulation of the hydrothermal system. Thermal budgets based on a simple model for this hydrothermal system indicate that the heat influx rate for local ''hot spots'' in the region may be large enough to account for the rate of heat flux from the entire Salton Trough.

  11. Sensitivity of modeled atmospheric nitrogen species and nitrogen deposition to variations in sea salt emissions in the North Sea and Baltic Sea regions

    NASA Astrophysics Data System (ADS)

    Neumann, Daniel; Matthias, Volker; Bieser, Johannes; Aulinger, Armin; Quante, Markus

    2016-03-01

    Coarse sea salt particles are emitted ubiquitously from the ocean surface by wave-breaking and bubble-bursting processes. These particles impact the atmospheric chemistry by affecting the condensation of gas-phase species and, thus, indirectly the nucleation of new fine particles, particularly in regions with significant air pollution. In this study, atmospheric particle concentrations are modeled for the North Sea and Baltic Sea regions in northwestern Europe using the Community Multiscale Air Quality (CMAQ) modeling system and are compared to European Monitoring and Evaluation Programme (EMEP) measurement data. The sea salt emission module is extended by a salinity-dependent scaling of the sea salt emissions because the salinity in large parts of the Baltic Sea is very low, which leads to considerably lower sea salt mass emissions compared to other oceanic regions. The resulting improvement in predicted sea salt concentrations is assessed. The contribution of surf zone emissions is considered separately. Additionally, the impacts of sea salt particles on atmospheric nitrate and ammonium concentrations and on nitrogen deposition are evaluated. The comparisons with observational data show that sea salt concentrations are commonly overestimated at coastal stations and partly underestimated farther inland. The introduced salinity scaling improves the predicted Baltic Sea sea salt concentrations considerably. The dates of measured peak concentrations are appropriately reproduced by the model. The impact of surf zone emissions is negligible in both seas. Nevertheless, they might be relevant because surf zone emissions were cut at an upper threshold in this study. Deactivating sea salt leads to minor increases in NH3 + NH4+ and HNO3 + NO3- and a decrease in NO3- concentrations. However, the overall effect on NH3 + NH4+ and HNO3 + NO3- concentrations is smaller than the deviation from the measurements. Nitrogen wet deposition is underestimated by the model at most

  12. box modeling of the eastern mediterranean sea

    NASA Astrophysics Data System (ADS)

    Ashkenazy, Y.; Stone, P. H.

    2003-04-01

    Recently (~1990) a new source of deep water formation in the Eastern Mediterranean was found in the southern part of the Aegean sea. Till then, the only source of deep water formation in the Eastern Mediterranean was in the Adriatic sea; the rate of the deep water formation of the new Aegean source is 1Sv=10^6m^3/s, three times larger then the Adriatic source. We develop a simple 3 box-model to study the stability of the thermohaline circulation of the Eastern Mediterranean sea. The 3 boxes represent the Adriatic sea, Aegean sea, and the Ionian sea. The boxes exchange heat and salinity and may be described by a set of nonlinear differential equations. We analytically analyze these equations and find that the system may have one, two, or four stable flux states. We consider two cases for which the temperatures of the boxes are (i) fixed or (ii) variable. After setting the parameters to correspond to the Eastern Mediterranean we find that the system has two stable states, one with (i) two thermally dominant sources of deep water formation in the Adriatic and Aegean and the other with (ii) a salinity dominant source of deep water formation in the Adriatic and a thermally dominant source in the Aegean. While the Adriatic thermally dominant source is comparable to the observed flux of 0.3Sv the Aegean source has much smaller flux than the observed value. This situation is analogous to the state of the thermohaline circulation pre 1990 where the only source of deep water formation was in the Adriatic. If we decrease the atmospheric temperature of the Aegean box by 2C in accordance with recent observations, we find that the deep water formation of the Aegean increases significantly to a value comparable to the recently observed flux.

  13. 15 CFR 918.5 - Eligibility, qualifications, and responsibilities-Sea Grant Regional Consortia.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... administrations, regional authorities, regional business and industry, and other regional educational institutions... to Commerce and Foreign Trade (Continued) NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT... qualifying areas which are pertinent to the Consortium's program: (1) Leadership. The Sea Grant...

  14. 15 CFR 918.5 - Eligibility, qualifications, and responsibilities-Sea Grant Regional Consortia.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... administrations, regional authorities, regional business and industry, and other regional educational institutions... to Commerce and Foreign Trade (Continued) NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT... qualifying areas which are pertinent to the Consortium's program: (1) Leadership. The Sea Grant...

  15. 15 CFR 918.5 - Eligibility, qualifications, and responsibilities-Sea Grant Regional Consortia.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... administrations, regional authorities, regional business and industry, and other regional educational institutions... to Commerce and Foreign Trade (Continued) NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT... qualifying areas which are pertinent to the Consortium's program: (1) Leadership. The Sea Grant...

  16. Regional Sea Level Variation: California Coastal Subsidence (Invited)

    NASA Astrophysics Data System (ADS)

    Blewitt, G.; Hammond, W. C.; Nerem, R.

    2013-12-01

    Satellite altimetry over the last two decades has measured variations in geocentric sea level (GSL), relative to the Earth system center of mass, providing valuable data to test models of physical oceanography and the effects of global climate change. The societal impacts of sea level change however relate to variations in local sea level (LSL), relative to the land at the coast. Therefore, assessing the impacts of sea level change requires coastal measurements of vertical land motion (VLM). Indeed, ΔLSL = ΔGSL - ΔVLM, with subsidence mapping 1:1 into LSL. Measurements of secular coastal VLM also allow tide-gauge data to test models of GSL over the last century in some locations, which cannot be provided by satellite data. Here we use GPS geodetic data within 15 km of the US west coast to infer regional, secular VLM. A total of 89 GPS stations met the criteria that time series span >4.5 yr, and do not have obvious non-linear variation, as may be caused by local instability. VLM rates for the GPS stations are derived in the secular reference frame ITRF2008, which aligns with the Earth system center of mass to ×0.5 mm/yr. We find that regional VLM has different behavior north and south of the Mendocino Triple Junction (MTJ). The California coast has a coherent regional pattern of subsidence averaging 0.5 mm/yr, with an increasing trend to the north. This trend generally matches GIA model predictions. Around San Francisco Bay, the observed coastal subsidence of 1.0 mm/yr coherently decreases moving away from the Pacific Ocean to very small subsidence on the east shores of the bay. This gradient is likely caused by San Andreas-Hayward Fault tectonics, and possibly by differential surface loading across the bay and Sacramento-San Joachim River Delta. Thus in addition to the trend in subsidence from GIA going northward along the California coast, tectonics may also play a role where the plate boundary fault system approaches the coast. In contrast, we find that VLM

  17. Modeling of the anthropogenic tritium transient, and its decay product Helium-3, in the Mediterranean Sea, using a high-resolution regional model.

    NASA Astrophysics Data System (ADS)

    Ayache, Mohamed; Dutay, Jean-Claude; Jean-Baptiste, Philippe; Beranger, Karine; Arsouze, Thomas; Beuvier, Jonathan; Palmieri, Julien; Le-Vu, Briac; Roether, Wolfgang

    2014-05-01

    This numerical study provides, for the first time in the Mediterranean Sea, a simulation of the anthropogenic tritium invasion and its decay product helium-3. The simulation is starting in 1950 and go up to 2011. It thus covers a 60-year period spanning the entire tritium transient generated by the atmospheric nuclear-weapon tests performed in the 1950s and early 1960s. The tritium is known as a passive tracer, which allows a good representation/signature of the upper water stratification, as well as, the high mixing in convection areas and the spreading at intermediate/deep levels. The tracer simulation is done using a high resolution regional model NEMO-MED12 (Beuvier et al., JGR, 2012) with at surface prescribed tritium concentration according to the temporal evolution derived from observations (see Roether et al., OS, 2013). Several measurement of tritium and helium-3 performed along large scale transects in the Mediterranean Sea during the last decades allow a comparison of the simulated results with numerous in situ sections from cruises of Meteor M5/6, M31/1, M44/4, M51/2, M84/3, and Poseidon 234. The results show that the parameterization used for the tritium boundary conditions generates realistic results. Besides we calculate the tracer-age distributions according to the relationship between tritium and its radioactive decay product helium-3. In the eastern basin, the tracer simulation results highlight the weak formation of Adriatic Deep Water (ADW) in the Adriatic Sea followed by a week contribution to the Eastern Mediterranean Deep Water (EMDW) in the Ionian sub-basin while it shows a good representation of the Eastern Mediterranean Transient (EMT) signal from the Aegean Sea followed by a great contribution to the EMDW. In the western basin, the particularly intense deep convection event of winter 2005 in the Gulf of Lions during the Western Mediterranean Transition (WMT) is well simulated. However the spreading of the recently ventilated deep water to

  18. Mesozooplankton in the open Black Sea: Regional and seasonal characteristics

    NASA Astrophysics Data System (ADS)

    Arashkevich, Elena G.; Stefanova, Kremena; Bandelj, Vinko; Siokou, Ioanna; Terbiyik Kurt, Tuba; Ak Orek, Yesim; Timofte, Florin; Timonin, Alexander; Solidoro, Cosimo

    2014-07-01

    Coordinated cruises conducted in the Black Sea offshore waters in spring and autumn 2008, within the framework of European project SESAME, allowed the obtainment of a quasi-synoptic picture of the mesozooplankton standing stock and community composition. A clear spatial difference in total abundance was observed in spring with higher values over the slope than over the deep basin, due to the development of the fast boundary current. In autumn, standing stock was lower than in spring; weakening of the boundary current and extensive eddy formation caused small-scale variability in mesozooplankton distribution and intensification of the exchange between the different parts of the sea. In both seasons, copepods comprised the bulk (62-95%) of mesozooplankton biomass. Community composition variability was tested for the first time using data obtained from the entire basin; the application of neural network analysis (Self-organizing Maps) revealed a rather homogenous picture of community composition. The development of cladocerans in autumn resulted in the differentiation of the slope areas from the deep basin. Mass development of the heterotrophic dinoflagellate Noctiluca scintillans was observed in the western and north-western areas in autumn. No change in standing stock values and community composition seem to have occurred since 2000 in the north-eastern region.

  19. Sensitivity of modeled atmospheric nitrogen species to variations in sea salt emissions in the North and Baltic Sea regions

    NASA Astrophysics Data System (ADS)

    Neumann, D.; Matthias, V.; Bieser, J.; Aulinger, A.; Quante, M.

    2015-10-01

    Coarse sea salt particles are emitted ubiquitously from the oceans' surfaces by wave breaking and bubble bursting processes. These particles impact atmospheric chemistry by affecting condensation of gas-phase species and nucleation of new fine particles, particularly in regions with high air pollution. In this study, atmospheric particle concentrations are modeled for the North and Baltic Sea regions, Northwestern Europe, using the Community Multiscale Air Quality (CMAQ) modeling system and evaluated against European Monitoring and Evaluation Programme (EMEP) measurement data. As model extension, sea salt emissions are scaled by water salinity because of low salinity in large parts of the Baltic Sea and in certain river estuaries. The resulting improvement in predicted sea salt concentrations is assessed. The contribution of surf zone emissions is separately considered. Additionally, the impact of sea salt particles on atmospheric nitrate, ammonium and sulfate concentrations is evaluated. The comparisons show that sea salt concentrations are commonly overestimated at coastal stations and partly underestimated when going inland. The introduced salinity scaling improves predicted Baltic Sea sea salt concentrations considerably. Dates of measured peak concentrations are appropriately reproduced by the model. The impact of surf zone emissions is negligible in both seas. Nevertheless, they might be relevant because surf zone emissions were cut at an upper threshold in this study. Deactivating sea salt leads to a minor increase of NH4+ and NO3- and a minor decrease of SO42- concentrations. However, the overall effect is very low and lower than the deviation from measurements. Size resolved measurements of Na+, NH4+, NO3-, and SO42- are needed for a more detailed analysis on the impact of sea salt particles.

  20. Backarc extension, detachments and granitoids in the Aegean, their relations to slab tear and asthenospheric flow

    NASA Astrophysics Data System (ADS)

    Jolivet, Laurent; Menant, Armel; Rabillard, Aurélien; Arbaret, Laurent; Augier, Romain; Gumiaux, Charles

    2013-04-01

    The Cycladic granitoids (Ikaria, Mykonos, Naxos, Kos, Lavrion, Serifos, Tinos) intruded the Aegean crust during a rather short period (17-10 Ma) compared to the much longer Oligo-Miocene crustal thinning phase (35 Ma to the Present). Their geochemical characteristics show that their sources have changed through time and space, with a progressive decreasing component of continental crust contamination with time and from east to west. They all interacted with large-scale detachments, namely the North Cycladic Detachment System (NCDS) in the north and the West Cycladic Detachment System (WCDS) in the south. In Mykonos, Naxos, Serifos and Ikaria the plutons are also associated with a high-temperature metamorphic dome of Miocene age. Their intrusion period roughly covers the same time window as the fast clockwise rotation of the western Aegean evidenced by paleomagnetic measurements and they are contemporaneous with a surge of alkaline volcanism in the eastern Aegean that can be related to a slab tear imaged below western Anatolia. The continental crust component in the Middle Miocene Cycladic plutons is not found in the early Miocene plutons of the northern Aegean, like in Kavala and Vrondou. They thus probably record a quite sudden thermal event in the Cyclades that led to the partial melting of the extending deep crust. We propose a model involving slab tear starting at ~17 Ma, fast retreat of the slab west of the tear and southwestward influx of hot asthenospheric material below the Aegean crust, leading to melting of the lower crust. Partial melting of the whole lower crust above the hot asthenospheric flow could explain the flat Moho observed below the Cyclades. The close proximity of plutons with the detachments suggests that their ascent toward the upper crust is favoured by the extreme extension at work there. The first granitoids in the region of the tear (Ikaria) are the richest in crustal component and this component decreases while the crust thins more and

  1. On the geodynamics of the Aegean rift

    NASA Astrophysics Data System (ADS)

    Agostini, Samuele; Doglioni, Carlo; Innocenti, Fabrizio; Manetti, Piero; Tonarini, Sonia

    2010-06-01

    The Aegean rift is considered to be either a classic backarc basin, or the result of the westward escape of Anatolia, or the effect of a gravitational collapse of an over-thickened lithosphere. Here these models are questioned. We alternatively present a number of geodynamic and magmatic constraints suggesting a simple model for the genesis of the extension as being related to the differential advancement of the upper lithosphere over a heterogeneous lower African plate. The Greek microplate overrides the Ionian oceanic segment of the African plate faster than the Anatolian microplate over the thicker Levantine more continental segment. This setting is evidenced by GPS-velocity gradient in the hangingwall of the Hellenic-Cyprus subduction system and requires a zone of rifting splitting the hangingwall into two microplates. This mechanism is unrelated to the replacement of retreated slab by the asthenosphere as typically occurs in the backarc of west-directed subduction zones. The supposed greater dehydration of the Ionian segment of the slab is providing a larger amount of fluids into the low velocity channel at the top of the asthenosphere, allowing a faster decoupling between the Greek microplate and the underlying mantle with respect to the Anatolian microplate. Slab ruptures associated with the differential retreat controlled by the inherited lithospheric heterogeneities in the lower plate and the proposed upwelling of the mantle suggested by global circulation models would explain the occurrence and coexistence of slab-related and slab-unrelated magmatism.

  2. Arc-continent collision in Banda Sea region

    SciTech Connect

    Bowin, C.; Purdy, G.M.; Johnston, C.; Shor, G.; Lawver, L.; Hartono, H.M.S.; Jezek, P.

    1980-06-01

    A 2-month marine geophysical study of the Banda arc region was conducted in late 1976 using the R/V Atlantis II of WHOI' and the R/V Thomas Washington of SIO; 19 seismic refraction lines were successfully completed. Oceanic crust underlies the Banda Sea and Weber Deep. Continental crust 35 to 40 km thick underlies the Australian Shelf. Thick continental crust is also present beneath the Timor and Aru Troughs. Low-amplitude magnetic anomalies are present over the Australian Shelf and extend to near the western edge of the Banda outer arc and, together with the presence of metamorphic rocks, suggest that continental crust may extend to the eastern lip of the Weber Deep. Continuous seismic reflection profiling shows the Australian Shelf sedimentary sequence dipping beneath the accretionary prisms of the outer Banda arc at the Timor and Seram Troughs: the tectonic front of the subduction zone lies along the axis of these troughs. The bathymetric profile on the outer flank of the Timor and Seram Troughs is unusual in that the profile asymptotically approaches a shallow depth near sea level and no outer rise is present as at oceanic trenches. It is concluded that the Outer Banda arc from Buru around to Timor, and possibly to Sumba, contained Australian continental crustal blocks and fragments prior to its collision with the Australian margin in the last 3 to 6 m.y. Continuous convergence following the addition of a thick Australian margin sedimentary sequence to the south Banda subduction zone has led to deformation being distributed over the width of the arc and not simply being taken up on a single thrust surface. This scenario helps reconcile the geologic relations on Timor, Seram, and Buru with the structural continuity of the Timor Trough with the Java Trench. 30 figures, 1 table.

  3. Diversity and Distribution of Deep-Sea Shrimps in the Ross Sea Region of Antarctica

    PubMed Central

    Basher, Zeenatul; Bowden, David A.; Costello, Mark J.

    2014-01-01

    Although decapod crustaceans are widespread in the oceans, only Natantia (shrimps) are common in the Antarctic. Because remoteness, depth and ice cover restrict sampling in the South Ocean, species distribution modelling is a useful tool for evaluating distributions. We used physical specimen and towed camera data to describe the diversity and distribution of shrimps in the Ross Sea region of Antarctica. Eight shrimp species were recorded: Chorismus antarcticus; Notocrangon antarcticus; Nematocarcinus lanceopes; Dendrobranchiata; Pasiphaea scotiae; Pasiphaea cf. ledoyeri; Petalidium sp., and a new species of Lebbeus. For the two most common species, N. antarcticus and N. lanceopes, we used maximum entropy modelling, based on records of 60 specimens and over 1130 observations across 23 sites in depths from 269 m to 3433 m, to predict distributions in relation to environmental variables. Two independent sets of environmental data layers at 0.05° and 0.5° resolution respectively, showed how spatial resolution affected the model. Chorismus antarcticus and N. antarcticus were found only on the continental shelf and upper slopes, while N. lanceopes, Lebbeus n. sp., Dendrobranchiata, Petalidium sp., Pasiphaea cf. ledoyeri, and Pasiphaea scotiae were found on the slopes, seamounts and abyssal plain. The environmental variables that contributed most to models for N. antarcticus were depth, chlorophyll-a concentration, temperature, and salinity, and for N. lanceopes were depth, ice concentration, seabed slope/rugosity, and temperature. The relative ranking, but not the composition of these variables changed in models using different spatial resolutions, and the predicted extent of suitable habitat was smaller in models using the finer-scale environmental layers. Our modelling indicated that shrimps were widespread throughout the Ross Sea region and were thus likely to play important functional role in the ecosystem, and that the spatial resolution of data needs to be

  4. Diversity and distribution of deep-sea shrimps in the Ross Sea region of Antarctica.

    PubMed

    Basher, Zeenatul; Bowden, David A; Costello, Mark J

    2014-01-01

    Although decapod crustaceans are widespread in the oceans, only Natantia (shrimps) are common in the Antarctic. Because remoteness, depth and ice cover restrict sampling in the South Ocean, species distribution modelling is a useful tool for evaluating distributions. We used physical specimen and towed camera data to describe the diversity and distribution of shrimps in the Ross Sea region of Antarctica. Eight shrimp species were recorded: Chorismus antarcticus; Notocrangon antarcticus; Nematocarcinus lanceopes; Dendrobranchiata; Pasiphaea scotiae; Pasiphaea cf. ledoyeri; Petalidium sp., and a new species of Lebbeus. For the two most common species, N. antarcticus and N. lanceopes, we used maximum entropy modelling, based on records of 60 specimens and over 1130 observations across 23 sites in depths from 269 m to 3433 m, to predict distributions in relation to environmental variables. Two independent sets of environmental data layers at 0.05° and 0.5° resolution respectively, showed how spatial resolution affected the model. Chorismus antarcticus and N. antarcticus were found only on the continental shelf and upper slopes, while N. lanceopes, Lebbeus n. sp., Dendrobranchiata, Petalidium sp., Pasiphaea cf. ledoyeri, and Pasiphaea scotiae were found on the slopes, seamounts and abyssal plain. The environmental variables that contributed most to models for N. antarcticus were depth, chlorophyll-a concentration, temperature, and salinity, and for N. lanceopes were depth, ice concentration, seabed slope/rugosity, and temperature. The relative ranking, but not the composition of these variables changed in models using different spatial resolutions, and the predicted extent of suitable habitat was smaller in models using the finer-scale environmental layers. Our modelling indicated that shrimps were widespread throughout the Ross Sea region and were thus likely to play important functional role in the ecosystem, and that the spatial resolution of data needs to be

  5. Characteristics of convective boundary layer over the Arabian sea region

    SciTech Connect

    Parasnis, S.S.

    1996-12-31

    The Convective Boundary Layer (CBL) over the oceanic regions plays an important role in regulating the transport of energy and moisture upward into the atmosphere from the surface. CBL structure over the Arabian sea region has been explored using the aerological soundings at two ships viz. SHIRSHOV (12.5{degrees}N, 68{degrees}E ) and OKEAN (14.5{degrees} N, 66{degrees} E) during MONSOON-77. Conserved variable analysis of the mean data sets obtained during the period of 29 June - 16 July, 1977 revealed salient features of the CBL over these regions. The vertical gradients of saturation point parameters viz. virtual potential temperature ({Theta}{sub v}), equivalent potential temperature ({Theta}{sub e}), saturated equivalent potential temperature ({Theta}{sub es}), saturation pressure deficit (P*) and the mixing ratio (q) were used to characterize the different sublayers such as subcloud layer, cloud layer and inversion/stable layer. The mean cloud base was around 950 hPa and the subcloud layer has nearly constant {Theta}{sub v}. The moist layer was associated with unstable {Theta}{sub es} with nearly constant value of P* ({approximately} -40 hPa). This cloud layer was capped by the stable (over OKEAN). The {Theta}{sub e} minimum over OKEAN was observed at 650 hPa (50 hPa above the CBL top) indicating that at some time the convection had reached deeper levels. The {Theta}{sub e} -q diagrams showed a characteristic mixing line up through the cloud and stable layer to the top of CBL. The low level stability analysis using the {Theta}{sub e} and {Theta}{sub es} profiles indicated conditions favorable for shallow convection over OKEAN and for deep convection over SHIRSHOV. The above characteristic features could be attributed to the prevailing weather conditions at OKEAN and SHIRSHOV. The results are discussed.

  6. Nestedness in centipede (Chilopoda) assemblages on continental islands (Aegean, Greece)

    NASA Astrophysics Data System (ADS)

    Simaiakis, Stylianos Michail; Martínez-Morales, Miguel Angel

    2010-05-01

    In natural ecosystems, species assemblages among isolated ecological communities such as continental islands often show a nested pattern in which biotas of sites with low species richness are non-random subsets of biotas of richer sites. The distribution of centipede (Chilopoda) species in the central and south Aegean archipelago was tested for nestedness. To achieve this aim we used distribution data for 53 species collected on 24 continental Aegean islands (Kyklades and Dodekanisa). Based on the first-order jackknife estimator, most of islands were comprehensively surveyed. In order to quantify nestedness, we used the nestedness temperature calculator (NTC) as well as the nestedness metric based on overlap and decreasing Fill (NODF). NTC indicated that data exhibited a high degree of nestedness in the central and south Aegean island complexes. As far as the Kyklades and Dodekanisa are concerned, NTC showed less nested centipede structures than the 24 islands. Likewise, NODF revealed a significant degree of nestedness in central and south Aegean islands. It also showed that biotas matrices without singletons were more nested than the complete ones (Aegean, Kyklades and Dodekanisa). The two commonest centipede taxa (lithobiomorphs and geophilomorphs) contributed differently to centipede assemblages. In the Kyklades and Dodekanisa, geophilomorphs did not show a reliable nested arrangement unlike lithobiomorphs. In relation to the entire data set, nestedness was positively associated with the degree of isolation. In the Kyklades altitudinal range best explained nestedness patterns, while in Dodekanisa habitat heterogeneity proved to be more important for the centipede communities. Island area does not seem to be a significant explanatory variable. Some of our results from the Kyklades were critically compared with those for terrestrial isopod and land snail nested assemblages from the same geographical area. The complex geological and palaeogeographical history of

  7. Magnetotellurics and Transient Electromagnetics to Investigate the Geoelectric Structure of Southern Aegean, Greece

    NASA Astrophysics Data System (ADS)

    Makris, J. P.; Kalisperi, D.; Smirnov, M.; Rigakis, H.; Romano, G.; Kokologiannakis, A.; Pentes, G.; Pentaris, F.; Skoulakis, A.; Perrone, A.; Kouli, M.; Vallianatos, F.

    2014-12-01

    Since 2012 a great number of onshore magnetotelluric (MT) and Transient Electromagnetic (TEM) measurements have been conducted in Southern Aegean, Greece. The survey included Crete, almost all the islands of Dodecanese and Southern Cyclades, Southern Peloponnese, and the islands Kithira, Antikithira and Gavdos. Southern Aegean Sea, featuring the Southern Hellenic Arc (HA) of the Hellenic Subduction Zone (HSZ) and the Hellenic Volcanic Arc (HVA), depicts complex geotectonics and the most intense seismicity and geodynamics of Western Eurasia. In this work we summarize the most important results of the MT and TEM combined analysis and modelling. Furthermore, two permanent telemetric MT stations were installed and operated in Western Crete and Rhodes, respectively, to be used as remote reference and to investigate possible transient seismoelectromagnetic signals. The case of the October 12, 2013 strong earthquake (Mb6.4) is discussed. The research was conducted in the framework of the project entitled "MagnetoTellurics in studying Geodynamics of the hEllenic Arc (MT-GEAR)", co-funded by the European Social Fund (ESF) and National Resources within the context of the Action "Supporting Postdoctoral Researchers" of the Operational Programme 'Education and Lifelong Learning'.

  8. Regional seasonal forecasts of the Arctic sea ice in two coupled climate models

    NASA Astrophysics Data System (ADS)

    Chevallier, Matthieu; Guémas, Virginie; Salas y Mélia, David; Doblas-Reyes, Francisco

    2015-04-01

    The predictive capabilities of two state-of-the-art coupled atmosphere-ocean global climate models (CNRM-CM5.1 and EC-Earth v2.3) in seasonal forecasting of the Arctic sea ice will be presented with a focus on regional skill. 5-month hindcasts of September sea ice area in the Arctic peripherial seas (Barents-Kara seas, Laptev-East Siberian seas, Chukchi sea and Beaufort sea) and March sea ice area in the marginal ice zones (Barents, Greenland, Labrador, Bering and Okhotsk sea) have been produced over the period 1990-2009. Systems mainly differ with respect to the initialization strategy, the ensemble generation techniques and the sea ice components. Predictive skill, assessed in terms of actual and potential predictability, is comparable in the two systems for both summer and winter hindcasts. Most interestingly, the multi-model prediction is often better than individual predictions in several sub-basins, including the Barents sea in the winter and most shelf seas in the summer. Systematic biases are also reduced using the multi-model predictions. Results from this study show that a regional zoom of global seasonal forecasts could be useful for operational needs. This study also show that the multi-model approach may be the step forward in producing accurate and reliable seasonal forecasts based on coupled global climate models.

  9. A three-step model to assess shoreline and offshore susceptibility to oil spills: the South Aegean (Crete) as an analogue for confined marine basins.

    PubMed

    Alves, Tiago M; Kokinou, Eleni; Zodiatis, George

    2014-09-15

    This study combines bathymetric, geomorphological, geological data and oil spill predictions to model the impact of oil spills in two accident scenarios from offshore Crete, Eastern Mediterranean. The aim is to present a new three-step method of use by emergency teams and local authorities in the assessment of shoreline and offshore susceptibility to oil spills. The three-step method comprises: (1) real-time analyses of bathymetric, geomorphological, geological and oceanographic data; (2) oil dispersion simulations under known wind and sea current conditions; and (3) the compilation of final hazard maps based on information from (1) and (2) and on shoreline susceptibility data. The results in this paper show that zones of high to very-high susceptibility around the island of Crete are related to: (a) offshore bathymetric features, including the presence of offshore scarps and seamounts; (b) shoreline geology, and (c) the presence near the shore of sedimentary basins filled with unconsolidated deposits of high permeability. Oil spills, under particular weather and oceanographic conditions, may quickly spread and reach the shoreline 5-96 h after the initial accident. As a corollary of this work, we present the South Aegean region around Crete as a valid case-study for confined marine basins, narrow seaways, or interior seas around island groups.

  10. Investigations at regional scales of reconstruct sea level variability over the past 50 years

    NASA Astrophysics Data System (ADS)

    Becker, M.; Meyssignac, B.; Llovel, W.; Cazenave, A. A.; Rogel, P.

    2010-12-01

    Sea level rise is a major consequence of global warming, which threatens many low-lying, highly populated coastal regions of the world. In such regions, sea level rise amplifies other stresses due to natural phenomena (e.g., sediment load-induced ground subsidence in deltaic areas, vertical ground motions due to tectonics, volcanism and post-glacial rebound, etc.) or human activities (e.g., ground subsidence due to ground water pumping and/or oil extraction, urbanisation, etc.). Observations for the recent decades from tide gauges and satellite altimetry show that sea level rise is far from being geographically uniform. Here we present an analysis of decadal / multi-decadal sea level variations in a number of selected regions: Tropical Pacific, Indian Ocean, Gulf of Mexico and Caribbean region. For that purpose, we use a reconstruction of past sea level -last 50 years- based on the joint statistical analysis of tide gauge records and gridded sea level from an ocean circulation model. We highlight the sea level trends over the past 50 years in each region. Comparison between reconstructed sea-level trends with tide gauge records at sites not included in the reconstruction shows general good agreement, suggesting that regional trend patterns infer from the reconstruction are realistic (in addition, reconstructed sea-level agrees well with altimeter measurements since 1993). We find above-global average sea level rise since 1950 at several islands in the Eastern Tropical Pacific (Funafuti, Samoa, Kiribati, Cook Islands). Empirical Orthogonal Function (EOF) analyses are performed for each region to describe accurately the spatio-temporal interannual variability. We also compute spatial trend patterns in thermal expansion to determine which part of the observed regional sea level variability can be attributed to change in ocean temperature.

  11. Three-dimensional instantaneous dynamics modeling of present-day Aegean subduction

    NASA Astrophysics Data System (ADS)

    Glerum, Anne; Thieulot, Cedric; Pranger, Casper; van Hinsbergen, Douwe; Fraters, Menno; Spakman, Wim

    2015-04-01

    The Aegean region (Eastern Mediterranean) is exemplary of the interaction between crustal tectonics, plate motion, subduction and mantle flow: African subduction underneath the region has been continuous for at least the last 100 My, leading to about 2100-2500 km of subducted lithosphere residing in the mantle (van Hinsbergen et al., 2005). During this subduction, decoupled upper continental and oceanic crust accreted into a wedge of stacked nappes. In turn, these nappes have been significantly extended, predominantly during the last 25 My, due to the retreat of the African slab relative to Eurasia (van Hinsbergen and Schmid, 2012). As a first step to better understanding the coupling of the tectonic evolution of the crust and the underlying mantle dynamics, we are developing 3-D numerical models of the instantaneous dynamics of the present-day Aegean subduction system using the finite element code ASPECT (Kronbichler et al., 2012). The instantaneous models are set up with initial slab geometries derived from tomography and realistic plate boundary configurations and incorporate the major crustal weak zones of the overriding plate. Our modeling results in predictions of flow fields and stress, strain rate and rotation rate fields for the present-day tectonic setting of the Aegean region. By comparing our various model predictions to the widely available observations, such as focal mechanisms, GPS velocities and seismic anisotropy, we aim at an improved understanding of how mantle flow, subduction morphology and possibly slab segmentation, as well as the rheological behavior of the overriding plate, control present-day tectonic deformation. We expect to show preliminary results of this comparison. Kronbichler, M., Heister, T. and Bangerth, W. (2012), High Accuracy Mantle Convection Simulation through Modern Numerical Methods, Geophysical Journal International, 191, 12-29. Van Hinsbergen, D. J. J., Hafkenscheid, E., Spakman, W., Meulenkamp, J. E. and Wortel, R. (2005

  12. The Importance of a U.S. Security Strategy in the Caspian Black Sea Region

    DTIC Science & Technology

    2010-04-13

    between southeastern Europe and Asia Minor. Excluding its northern arm, the Sea of Azov , the Black Sea occupies about 168,500 square miles (436,400...Strategy in the Caspian Black Sea N/A Region Sb. GRANT NUMBER N/A Sc. PROGRAM ELEMENT NUMBER NIA 6. AUTHOR(S) Sd. PROJECT NUMBER Cobb, Scott E...STATEMENT Unlimited 13. SUPPLEMeNTARY NOTES N/A 14. ABSTRACT The Caspian Black Sea Region is located at the strategically important intersection of the

  13. Influence of coupling on atmosphere, sea ice and ocean regional models in the Ross Sea sector, Antarctica

    NASA Astrophysics Data System (ADS)

    Jourdain, Nicolas C.; Mathiot, Pierre; Gallée, Hubert; Barnier, Bernard

    2011-04-01

    Air-sea ice-ocean interactions in the Ross Sea sector form dense waters that feed the global thermohaline circulation. In this paper, we develop the new limited-area ocean-sea ice-atmosphere coupled model TANGO to simulate the Ross Sea sector. TANGO is built up by coupling the atmospheric limited-area model MAR to a regional configuration of the ocean-sea ice model NEMO. A method is then developed to identify the mechanisms by which local coupling affects the simulations. TANGO is shown to simulate realistic sea ice properties and atmospheric surface temperatures. These skills are mostly related to the skills of the stand alone atmospheric and oceanic models used to build TANGO. Nonetheless, air temperatures over ocean and winter sea ice thickness are found to be slightly improved in coupled simulations as compared to standard stand alone ones. Local atmosphere ocean feedbacks over the open ocean are found to significantly influence ocean temperature and salinity. In a stand alone ocean configuration, the dry and cold air produces an ocean cooling through sensible and latent heat loss. In a coupled configuration, the atmosphere is in turn moistened and warmed by the ocean; sensible and latent heat loss is therefore reduced as compared to the stand alone simulations. The atmosphere is found to be less sensitive to local feedbacks than the ocean. Effects of local feedbacks are increased in the coastal area because of the presence of sea ice. It is suggested that slow heat conduction within sea ice could amplify the feedbacks. These local feedbacks result in less sea ice production in polynyas in coupled mode, with a subsequent reduction in deep water formation.

  14. Does the Maritime Continent region affect sea level change of the eastern Indian Ocean?

    NASA Astrophysics Data System (ADS)

    Llovel, W.; Lee, T.

    2014-12-01

    The Maritime Continent region, in particular, the Indonesian Sea, regulates the oceanic communication between the Pacific and Indian Oceans. Previous studies suggest that the freshwater transported from the South China Sea to the Indonesian Sea affects the magnitude and structure of the Indonesian throughflow, and the strong tidal mixing in the Indonesian Sea alters the time mean vertical structure of the water mass carried from the Pacific to the Indian Oceans. Sea level changes in the eastern Indian Ocean is known to be affected by those in the northwestern Pacific via coastal Kelvin wave propagation through the Indonesian Sea. However, whether the Maritime Continent region influences sea level changes in the eastern Indian Ocean has not been investigated. In this study, we used Argo floats and satellite altimeter data to study the near decadal change of sea level during the 2005-2013 period. We found that the steric sea level change in eastern Indian Ocean cannot be fully explained by either local forcing or the transmission of steric signal from the western Pacific. This implicates the potential role of the Maritime Continent region in regulating sea level changes in the eastern Indian Ocean.

  15. Regional variability of a projected sea ice-free Arctic during the summer months

    NASA Astrophysics Data System (ADS)

    Laliberté, F.; Howell, S. E. L.; Kushner, P. J.

    2016-01-01

    Climate projections of sea ice retreat under anthropogenic climate change at the regional scale and in summer months other than September have largely not been evaluated. Information at this level of detail is vital for future planning of safe Arctic marine activities. Here the timing of when Arctic waters will be reliably ice free across Arctic regions from June to October is presented. It is shown that during this century regions along the Northern Sea Route and Arctic Bridge will be more reliably ice free than regions along the Northwest Passage and the Transpolar Sea Route, which will retain substantial sea ice cover past midcentury. Moreover, ice-free conditions in the Arctic will likely be confined to September for several decades to come in many regions. Projections using a selection of models that accounts for agreement of models in each region and calendar month with observations yield similar conclusions.

  16. Zircon crytallization and recycling in the magma chamber of the rhyolitic Kos Plateau Tuff (Aegean arc)

    USGS Publications Warehouse

    Bachman, O.; Charlier, B.L.A.; Lowenstern, J. B.

    2007-01-01

    In contrast to most large-volume silicic magmas in continental arcs, which are thought to evolve as open systems with significant assimilation of preexisting crust, the Kos Plateau Miff magma formed dominantly by crystal fractionation of mafic parents. Deposits from this ??? 60 km3 pyroclastic eruption (the largest known in the Aegean arc) lack xenocrystic zircons [secondary ion mass spectrometry (SIMS) U-Pb ages on zircon cores never older than 500 ka] and display Sr-Nd whole-rock isotopic ratios within the range of European mantle in an area with exposed Paleozoic and Tertiary continental crust; this evidence implies a nearly closed-system chemical differentiation. Consequently, the age range provided by zircon SIMS U-Th-Pb dating is a reliable indicator of the duration of assembly and longevity of the silicic magma body above its solidus. The age distribution from 160 ka (age of eruption by sanidine 40Ar/39Ar dating; Smith et al., 1996) to ca. 500 ka combined with textural characteristics (high crystal content, corrosion of most anhydrous phenocrysts, but stability of hydrous phases) suggest (1) a protracted residence in the crust as a crystal mush and (2) rejuvenation (reduced crystallization and even partial resorption of minerals) prior to eruption probably induced by new influx of heat (and volatiles). This extended evolution chemically isolated from the surrounding crust is a likely consequence of the regional geodynamics because the thinned Aegean microplate acts as a refractory container for magmas in the dying Aegean subduction zone (continent-continent subduction). ?? 2007 Geological Society of America.

  17. Zircon crystallization and recycling in the magma chamber of the rhyolitic Kos Plateau Tuff (Aegean arc)

    USGS Publications Warehouse

    Bachman, O.; Charlier, B.L.A.; Lowenstern, J. B.

    2007-01-01

    In contrast to most large-volume silicic magmas in continental arcs, which are thought to evolve as open systems with significant assimilation of preexisting crust, the Kos Plateau Tuff magma formed dominantly by crystal fractionation of mafic parents. Deposits from this ~60 km3 pyroclastic eruption (the largest known in the Aegean arc) lack xenocrystic zircons [secondary ion mass spectrometry (SIMS) U-Pb ages on zircon cores never older than 500 ka] and display Sr-Nd whole-rock isotopic ratios within the range of European mantle in an area with exposed Paleozoic and Tertiary continental crust; this evidence implies a nearly closed-system chemical differentiation. Consequently, the age range provided by zircon SIMS U-Th-Pb dating is a reliable indicator of the duration of assembly and longevity of the silicic magma body above its solidus. The age distribution from 160 ka (age of eruption by sanidine 40Ar/39Ar dating; Smith et al., 1996) to ca. 500 ka combined with textural characteristics (high crystal content, corrosion of most anhydrous phenocrysts, but stability of hydrous phases) suggest (1) a protracted residence in the crust as a crystal mush and (2) rejuvenation (reduced crystallization and even partial resorption of minerals) prior to eruption probably induced by new influx of heat (and volatiles). This extended evolution chemically isolated from the surrounding crust is a likely consequence of the regional geodynamics because the thinned Aegean microplate acts as a refractory container for magmas in the dying Aegean subduction zone (continent-continent subduction).

  18. High-resolution regional modelling of natural and anthropogenic radiocarbon in the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Ayache, Mohamed; Dutay, Jean-Claude; Mouchet, Anne; Tisnérat-Laborde, Nadine; Montagna, Paolo; Tanhua, Toste; Siani, Giuseppe; Jean-Baptiste, Philippe

    2017-03-01

    A high-resolution dynamical model (Nucleus for European Modelling of the Ocean, Mediterranean configuration - NEMO-MED12) was used to give the first simulation of the distribution of radiocarbon (14C) across the whole Mediterranean Sea. The simulation provides a descriptive overview of both the natural pre-bomb 14C and the entire anthropogenic radiocarbon transient generated by the atmospheric bomb tests performed in the 1950s and early 1960s. The simulation was run until 2011 to give the post-bomb distribution. The results are compared to available in situ measurements and proxy-based reconstructions. The radiocarbon simulation allows an additional and independent test of the dynamical model, NEMO-MED12, and its performance to produce the thermohaline circulation and deep-water ventilation. The model produces a generally realistic distribution of radiocarbon when compared with available in situ data. The results demonstrate the major influence of the flux of Atlantic water through the Strait of Gibraltar on the inter-basin natural radiocarbon distribution and characterize the ventilation of intermediate and deep water especially through the propagation of the anthropogenic radiocarbon signal. We explored the impact of the interannual variability on the radiocarbon distribution during the Eastern Mediterranean Transient (EMT) event. It reveals a significant increase in 14C concentration (by more than 60 ‰) in the Aegean deep water and at an intermediate level (value up to 10 ‰) in the western basin. The model shows that the EMT makes a major contribution to the accumulation of radiocarbon in the eastern Mediterranean deep waters.

  19. Features of Malignancy Prevalence among Children in the Aral Sea Region

    PubMed

    Mamyrbayev, Arstan; Dyussembayeva, Nailya; Ibrayeva, Lyazzat; Satenova, Zhanna; Tulyayeva, Anara; Kireyeva, Nurgul; Zholmukhamedova, Dinara; Rybalkina, Dina; Yeleuov, Galymzhan; Yeleuov, Almasbek

    2016-12-01

    Objective: A study of primary cancer morbidity among children and subsequent calculation of average annual incidence were carried out for boys and girls, and young men and women in Kazakhstan. Methods: The investigated population lived in three areas of the Aral Sea region: designated catastrophe (Aral, Kazalt, Shalkar regions), crisis (Zhalagash, Karmakshy, Shiely regions), pre-crisis (Irgiz, Arys, Ulytau regions). Zhanaarka region of Karaganda oblast was applied as a control. Parameters were retrospective analyzed for the 10 years from 2004 to 2013. Result: The results indicate that indices of children cancer morbidity were slightly higher in the Aral Sea region than in the control district, but they were comparable with similar data from studies in other regions. In all areas of the Aral Sea region, except for Ulytau, primary cancer morbidity exceeded the control level by 1.3-2.7 times (4.7%000). Hematological malignancies, including solid tumors - tumors of musculoskeletal system and skin, digestive system, brain and central nervous system predominated. Stress levels in zones of the Aral Sea region were slightly higher in the crisis zone than in the catastrophe zone that can be explained by the phenomenon of wave-like dynamics of disease growth risk. Gender differences in characteristics of malignancy formation were not more pronounced in the studied region. Conclusion: Indices of children cancer are slightly higher in the Aral Sea region than in the control area of Kazakhstan, but they are comparable to results for other regions.

  20. The regional geology and hydrocarbon potential of the Baltic Sea

    SciTech Connect

    Haselton, T.M. ); Brangulis, A.P.; Margulis, L.S. ); Kanev, S. )

    1991-08-01

    The Baltic Sea is roughly equivalent in size to the North Sea. Like the North Sea, is has an excellent oil prone source rock present over most of the area. In the entire Baltic Sea about 40 wells have been drilled. During the 1980s, exploration was carried out in the Soviet, Polish, and East German sectors of the Baltic Sea by Petrobaltic. Twenty-eight wells were drilled, 14 of which tested hydrocarbons. Two wells have been drilled in Danish waters and 11 in Swedish waters - all dry holes. Most of the Baltic Sea is included in the Baltic syneclise. In the deepest part of the basin a full Paleozoic and Mesozoic section is present. Major structural features are associated with reactivation of old basement faults. Most hydrocarbon discoveries are associated with structural arches. Exploration targets are Cambrian sandstones and Ordovician and Silurian reefs. The major discoveries are the B3 field in Poland and the D6 field offshore Lithuania and Kaliningrad, both of which have in-place reserves of around 100 million bbl. The Teisseyre-Tornquist line to the southwest represents the plate boundary between the East European platform and Europe. Repeated strike slip movements along this zone result in a complex pattern of extensional and compressional features in the Danish and German sectors. Primary exploration targets include Permian carbonates and sandstones as well as older zones. Gas has been tested in the German sector onshore.

  1. PREFACE: Donald D Harrington Symposium on the Geology of the Aegean

    NASA Astrophysics Data System (ADS)

    Catlos, Elizabeth J.

    2008-03-01

    This volume of the IOP Conference Series: Earth and Environmental Sciences presents a selection of papers given at the Donald D Harrington Symposium on the Geology of the Aegean held on the campus of the University of Texas at Austin on April 28-30, 2008. Donald D Harrington was born in Illinois in 1899 and moved westward after serving in the Army Air Corps during World War I. Mr Harrington took a position as a landman with Marlin Oil Company in Oklahoma. When the Texas Panhandle oil boom hit in 1926, he moved to Amarillo, Texas, where he met Sybil Buckingham—the granddaughter of one of Amarillo's founding families. They married in 1935 and went on to build one of the most successful independent oil and gas operations in Texas history. The couple created the Don and Sybil Harrington Foundation in 1951 to support worthy causes such as museums, medical research, education, and the arts. At the Harrington Symposium on the Geology of the Aegean, researchers presented papers organized under five general themes: (1) the geology of Aegean in general (2) the geologic history of specific domains within the Aegean (Cyclades, Menderes, Kazdag, Rhodope, Crete, southern Balkans, etc) (3) the dynamic tectonic processes that occur within the Aegean (4) its geo-archeological history, natural history and hazards and (5) comparisons of the Aegean to regions elsewhere (e.g., Basin and Ranges; Asian extensional terranes). The Aegean is a locus of dynamic research in a variety of fields, and the symposium provided an opportunity for geologists from a range of disciplines to interact and share new results and information about their research in the area. At the opening reception in the Harry S Ransom Center, Dr Clark Burchfiel (Massachusetts Institute of Technology, USA) provided a keynote address on the outstanding geologic problems of the Aegean region. His paper in this volume outlines a framework for future studies. We also call attention to a paper in this volume by Dr Y

  2. The impact of regional Arctic sea ice loss on atmospheric circulation and the NAO

    NASA Astrophysics Data System (ADS)

    Anker Pedersen, Rasmus; Cvijanovic, Ivana; Langen, Peter Lang; Vinther, Bo

    2016-04-01

    Reduction of the Arctic sea ice cover can affect the atmospheric circulation, and thus impact the climate beyond the Arctic. The atmospheric response may, however, vary with the geographical location of sea ice loss. The atmospheric sensitivity to the location of sea ice loss is studied using a general circulation model in a configuration that allows combination of a prescribed sea ice cover and an active mixed layer ocean. This hybrid setup makes it possible to simulate the isolated impact of sea ice loss and provides a more complete response compared to experiments with fixed sea surface temperatures. Three investigated sea ice scenarios with ice loss in different regions all exhibit substantial near-surface warming which peaks over the area of ice loss. The maximum warming is found during winter, delayed compared to the maximum sea ice reduction. The wintertime response of the mid-latitude atmospheric circulation shows a non-uniform sensitivity to the location of sea ice reduction. While all three scenarios exhibit decreased zonal winds related to high-latitude geopotential height increases, the magnitudes and locations of the anomalies vary between the simulations. Investigation of the North Atlantic Oscillation reveals a high sensitivity to the location of the ice loss. The northern center of action exhibits clear shifts in response to the different sea ice reductions. Sea ice loss in the Atlantic and Pacific sectors of the Arctic cause westward and eastward shifts, respectively.

  3. Regional sea level variability from ice sheets, glaciers and land hydrology

    NASA Astrophysics Data System (ADS)

    Velicogna, I.; Hsu, C. W.

    2014-12-01

    Closing the sea level budget is a most important scientific and societal issue of climate change. Here, we report on the status of ice sheets and glaciers mass balance throughout the world and their contribution to sea level rise using time series of time-variable gravity from the NASA/DLR GRACE satellite mission for the time period 2003-2014. We also evaluate static regional sea level variations (or sea level fingerprints, SLF) from these observations of ice sheet and glacier loss, combined with observations of changes in global land hydrology also from GRACE, and water input from the atmosphere from re-analysis data. We evaluate the relative contribution of each component to regional sea level. We compare the cumulative SLF signal at global scale and at the scale of large ocean basins with satellite altimetry data corrected for the steric component from Argo floats. We find an excellent agreement between the two datasets. Although the regional SLF do not include sea level variations from ocean dynamics that re-distributes water mass around the world's oceans at the analyzed scales, we find that the SLF represent a large fraction of the trend and annual amplitude of the sea level signal. We also show an analysis of the contributions of regional sea level from mass changes in Greenland and Antarctica going back to the 1970s. This work was conducted at the University of California Irvine and at Caltech's Jet Propulsion Laboratory under a contract with the National Aeronautics and Space Administration.

  4. On the regional characteristics of past and future sea-level change (Invited)

    NASA Astrophysics Data System (ADS)

    Timmermann, A.; McGregor, S.

    2010-12-01

    Global sea-level rise due to the thermal expansion of the warming oceans and freshwater input from melting glaciers and ice-sheets is threatening to inundate low-lying islands and coast-lines worldwide. At present global mean sea level rises at 3.1 ± 0.7 mm/yr with an accelerating tendency. However, the magnitude of recent decadal sea-level trends varies greatly spatially attaining values of up to 10 mm/yr in some areas of the western tropical Pacific. Identifying the causes of recent regional sea-level trends and understanding the patterns of future projected sea-level change is of crucial importance. Using a wind-forced simplified dynamical ocean model, we show that the regional features of recent decadal and multidecadal sea-level trends in the tropical Indo-Pacific can be attributed to changes in the prevailing wind-regimes. Furthermore it is demonstrated that within an ensemble of ten state-of-the art coupled general circulation models, forced by increasing atmospheric CO2 concentrations over the next century, wind-induced re-distributions of upper-ocean water play a key role in establishing the spatial characteristics of projected regional sea-level rise. Wind-related changes in near- surface mass and heat convergence near the Solomon Islands, Tuvalu, Kiribati, the Cook Islands and French Polynesia oppose, but can not cancel the regional signal of global mean sea-level rise.

  5. Regional differences in the spatial and temporal heterogeneity of oceanographic habitat used by Steller sea lions.

    PubMed

    Lander, Michelle E; Loughlin, Thomas R; Logsdon, Miles G; VanBlaricom, Glenn R; Fadely, Brian S; Fritz, Lowell W

    2009-09-01

    Over the past three decades, the decline and altered spatial distribution of the western stock of Steller sea lions (Eumetopias jubatus) in Alaska have been attributed to changes in the distribution or abundance of their prey due to the cumulative effects of fisheries and environmental perturbations. During this period, dietary prey occurrence and diet diversity were related to population decline within metapopulation regions of the western stock of Steller sea lions, suggesting that environmental conditions may be variable among regions. The objective of this study, therefore, was to examine regional differences in the spatial and temporal heterogeneity of oceanographic habitat used by Steller sea lions within the context of recent measures of diet diversity and population trajectories. Habitat use was assessed by deploying satellite-depth recorders and satellite relay data loggers on juvenile Steller sea lions (n = 45) over a five-year period (2000-2004) within four regions of the western stock, including the western, central, and eastern Aleutian Islands, and central Gulf of Alaska. Areas used by sea lions during summer months (June, July, and August) were demarcated using satellite telemetry data and characterized by environmental variables (sea surface temperature [SST] and chlorophyll a [chl a]), which possibly serve as proxies for environmental processes or prey. Spatial patterns of SST diversity and Steller sea lion population trends among regions were fairly consistent with trends reported for diet studies, possibly indicating a link between environmental diversity, prey diversity, and distribution or abundance of Steller sea lions. Overall, maximum spatial heterogeneity coupled with minimal temporal variability of SST appeared to be beneficial for Steller sea lions. In contrast, these patterns were not consistent for chl a, and there appeared to be an ecological threshold. Understanding how Steller sea lions respond to measures of environmental

  6. Cluster analysis of indermediate deep events in the southeastern Aegean

    NASA Astrophysics Data System (ADS)

    Ruscic, Marija; Becker, Dirk; Brüstle, Andrea; Meier, Thomas

    2015-04-01

    The Hellenic subduction zone (HSZ) is the seismically most active region in Europe where the oceanic African litosphere is subducting beneath the continental Aegean plate. Although there are numerous studies of seismicity in the HSZ, very few focus on the eastern HSZ and the Wadati-Benioff-Zone of the subducting slab in that part of the HSZ. In order to gain a better understanding of the geodynamic processes in the region a dense local seismic network is required. From September 2005 to March 2007, the temporary seismic network EGELADOS has been deployed covering the entire HSZ. It consisted of 56 onshore and 23 offshore broadband stations with addition of 19 stations from GEOFON, NOA and MedNet to complete the network. Here, we focus on a cluster of intermediate deep seismicity recorded by the EGELADOS network within the subducting African slab in the region of the Nysiros volcano. The cluster consists of 159 events at 80 to 190 km depth with magnitudes between 0.2 and 4.1 that were located using nonlinear location tool NonLinLoc. A double-difference earthquake relocation using the HypoDD software is performed with both manual readings of onset times and differential traveltimes obtained by separate cross correlation of P- and S-waveforms. Single event locations are compared to relative relocations. The event hypocenters fall into a thin zone close to the top of the slab defining its geometry with an accuracy of a few kilometers. At intermediate depth the slab is dipping towards the NW at an angle of about 30°. That means it is dipping steeper than in the western part of the HSZ. The edge of the slab is clearly defined by an abrupt disappearance of intermediate depths seismicity towards the NE. It is found approximately beneath the Turkish coastline. Furthermore, results of a cluster analysis based on the cross correlation of three-component waveforms are shown as a function of frequency and the spatio-temporal migration of the seismic activity is analysed.

  7. Warm Greenland during the last interglacial: the role of regional changes in sea ice cover

    NASA Astrophysics Data System (ADS)

    Merz, Niklaus; Born, Andreas; Raible, Christoph C.; Stocker, Thomas F.

    2016-10-01

    The last interglacial, also known as the Eemian, is characterized by warmer than present conditions at high latitudes. This is implied by various Eemian proxy records as well as by climate model simulations, though the models mostly underestimate the warming with respect to proxies. Simulations of Eemian surface air temperatures (SAT) in the Northern Hemisphere extratropics further show large variations between different climate models, and it has been hypothesized that this model spread relates to diverse representations of the Eemian sea ice cover. Here we use versions 3 and 4 of the Community Climate System Model (CCSM3 and CCSM4) to highlight the crucial role of sea ice and sea surface temperatures changes for the Eemian climate, in particular in the North Atlantic sector and in Greenland. A substantial reduction in sea ice cover results in an amplified atmospheric warming and thus a better agreement with Eemian proxy records. Sensitivity experiments with idealized lower boundary conditions reveal that warming over Greenland is mostly due to a sea ice retreat in the Nordic Seas. In contrast, sea ice changes in the Labrador Sea have a limited local impact. Changes in sea ice cover in either region are transferred to the overlying atmosphere through anomalous surface energy fluxes. The large-scale spread of the warming resulting from a Nordic Seas sea ice retreat is mostly explained by anomalous heat advection rather than by radiation or condensation processes. In addition, the sea ice perturbations lead to changes in the hydrological cycle. Our results consequently imply that both temperature and snow accumulation records from Greenland ice cores are sensitive to sea ice changes in the Nordic Seas but insensitive to sea ice changes in the Labrador Sea. Moreover, the simulations suggest that the uncertainty in the Eemian sea ice cover accounts for 1.6 °C of the Eemian warming at the NEEM ice core site. The estimated Eemian warming of 5 °C above present day

  8. Environmental Assessment for Selected Regions in the Mediterranean Sea

    DTIC Science & Technology

    1992-01-01

    Iti extends north to Sicily, Italy, and Greece, connecting the Adriatic Sea by the Strait of Otranto ; east to a line from Akra Kios south to 340N... Otranto into this basin.I. 2.3 Straits of Sicily and Sardinia I The Strait of Sicily separates the western Mediterranean basins from those of the

  9. Geopolitical Interests in the Black Sea / Caspian Region

    DTIC Science & Technology

    2011-03-21

    passing the overloaded Bosporus and Dardanelles Straits. For Russia and the coastal states of the Black Sea, but also for the countries of the...limitations; oil tankers with a length of over 200 meters or those which carry dangerous freights can pass the Straits only during the day, a fact

  10. A continuum model of continental deformation above subduction zones - Application to the Andes and the Aegean

    NASA Technical Reports Server (NTRS)

    Wdowinski, Shimon; O'Connell, Richard J.; England, Philip

    1989-01-01

    A continuum model of continental deformation above subduction zones was developed that combines the viscous sheet and the corner flow models; the continental lithosphere is described by a two-dimensional sheet model that considers basal drag resulting from the viscous asthenosphere flow underneath, and a corner flow model with a deforming overlying plate and a rigid subducting plate is used to calculate the shear traction that acts on the base of the lithosphere above a subduction zone. The continuum model is applied to the Andes and the Aegean deformations, which represent, respectively, compressional and extensional tectonic environments above subduction zones. The models predict that, in a compressional environment, a broad region of uplifted topography will tend to develop above a more steeply dippping slab, rather than above a shallower slab, in agreement with observations in the various segments of the central Andes. For an extensional environment, the model predicts that a zone of compression can develop near the trench, and that extensional strain rate can increase with distance from the trench, as is observed in the Aegean.

  11. Satellite microwave radiometry of sea ice of polar regions: a review

    NASA Astrophysics Data System (ADS)

    Tikhonov, V. V.; Raev, M. D.; Sharkov, E. A.; Boyarskii, D. A.; Repina, I. A.; Komarova, N. Yu.

    2016-12-01

    This is a review of methods of passive microwave satellite monitoring of the sea-ice cover in polar regions. We briefly describe the microwave radiometers launched into the Earth's orbit and provide data used in studies of Arctic and Antarctic sea ice. We give a detailed description of currently used algorithms for determining the sea-ice concentration and cover in polar regions according to satellite microwave radiometry. The methods for constructing these algorithms and their related drawbacks are considered. The final section of this paper briefly analyzes the studies that compare current algorithms with each other, with radar data, infrared data, and data of visual ship observations.

  12. Quantifying some of the impacts of dust and other aerosol on the Caspian Sea region using a regional climate model

    NASA Astrophysics Data System (ADS)

    Elguindi, N.; Solmon, F.; Turuncoglu, U.

    2016-01-01

    The Central Asian deserts are a major dust source region that can potentially have a substantial impact on the Caspian Sea. Despite major advances in the modeling and prediction of the Caspian Sea Level (CSL) during recent years, no study to date has investigated the climatic effects of dust on the hydrological budget of the Sea. In this study, we utilize a regional climate model coupled to an interactive emission and transport scheme to simulate the effects of dust and other aerosol in the Caspian region. First, we present a validation of the model using a variety of AOD satellite observations as well as a climatology of dust storms. Compared to the range of satellite estimates, the model's AOD climatology is closer to the lower end of the observations, and exhibit a significant underestimation over the clay deserts found on the Ustyurt plateau and north of the Aral Sea. Nevertheless, we find encouraging results in that the model is able to reproduce the gradient of increasing AOD intensity from the middle to the southern part of the Sea. Spatially, the model reproduces reasonably well the observed climatological dust storm frequency maps which show that the most intense dust source regions to be found in the Karakum desert in Turkmenistan and Kyzylkum desert in Uzbekistan east of the Aral Sea. In the second part of this study we explore some impacts of dust and other aerosol on the climatology of the region and on the energy budget of the Sea. We find that the overall direct radiative effects of dust and other aerosol reduce the amount of shortwave radiation reaching the surface, dampen boundary layer turbulence and inhibit convection over the region. We also show that by including dust and aerosol in our simulation, we are able to reduce the positive biases in sea surface temperatures by 1-2 °C. Evaporation is also considerably reduced, resulting in an average difference of approximately 10 mm year^{-1} in the Sea's hydrological budget which is substantial

  13. Regional Changes in the Sea Ice Cover and Ice Production in the Antarctic

    NASA Technical Reports Server (NTRS)

    Comiso, Josefino C.

    2011-01-01

    Coastal polynyas around the Antarctic continent have been regarded as sea ice factories because of high ice production rates in these regions. The observation of a positive trend in the extent of Antarctic sea ice during the satellite era has been intriguing in light of the observed rapid decline of the ice extent in the Arctic. The results of analysis of the time series of passive microwave data indicate large regional variability with the trends being strongly positive in the Ross Sea, strongly negative in the Bellingshausen/Amundsen Seas and close to zero in the other regions. The atmospheric circulation in the Antarctic is controlled mainly by the Southern Annular Mode (SAM) and the marginal ice zone around the continent shows an alternating pattern of advance and retreat suggesting the presence of a propagating wave (called Antarctic Circumpolar Wave) around the circumpolar region. The results of analysis of the passive microwave data suggest that the positive trend in the Antarctic sea ice cover could be caused primarily by enhanced ice production in the Ross Sea that may be associated with more persistent and larger coastal polynyas in the region. Over the Ross Sea shelf, analysis of sea ice drift data from 1992 to 2008 yields a positive rate-of-increase in the net ice export of about 30,000 km2 per year. For a characteristic ice thickness of 0.6 m, this yields a volume transport of about 20 km3/year, which is almost identical, within error bars, to our estimate of the trend in ice production. In addition to the possibility of changes in SAM, modeling studies have also indicated that the ozone hole may have a role in that it causes the deepening of the lows in the western Antarctic region thereby causing strong winds to occur offthe Ross-ice shelf.

  14. A Regional Model for Seasonal Sea Ice Prediction in the Pacific Sector of the Arctic

    NASA Astrophysics Data System (ADS)

    Yuan, X.; Li, Y.; Chen, D.; Zhang, Q.; Li, C.; Niu, F.; Sun, Y.

    2015-12-01

    The recent results from a linear Markov model for seasonal prediction of pan-Arctic sea ice concentration (SIC) show that sea ice in the Pacific sector has the lowest predictability compared to other regions. One reason could be that the climate variability in the Atlantic sector is so dominant that other signals in the Arctic climate system do not appear in the leading modes used for model construction. This study develops a regional Markov model to improve seasonal forecasting of SIC in the Pacific sector. The model climate system consists of various combinations of the monthly mean series of SIC, sea surface temperature (SST), surface air temperature (SAT), pressure/geopotential height fields and winds at pressure levels. Multivariate empirical orthogonal functions (MEOF) and rotated MEOF are applied to each set of data to reduce the model dimensions. After a series of experiments, the final model configuration selects 23 rotated MEOF modes from a data matrix of three variables (SIC, SST and SAT). This regional model shows considerable improvement in the prediction skill in the Pacific sector in all seasons. The anomaly correlation skill increases by 0.2 at 1- to 4-month leads in the Bering Sea, and by 0.1 at 1- to 10-month leads in the Sea of Okhotsk. In general, the model performs better in summer and fall than in winter and spring. On average, the correlation skill can reach 0.6 at a 2-month (4-month) lead in the Bering Sea (the Sea of Okhotsk).

  15. Seismic features of regional earthquakes around the Yellow Sea and their tectonic implications

    NASA Astrophysics Data System (ADS)

    Choi, H.; Hong, T.

    2012-12-01

    The Yellow Sea belongs to the eastern Eurasian plate. It is surrounded by the eastern China and Korean Peninsula. It is known that there is a collision belt between the North and South China blocks, which may be extended to the Korean Peninsula. The location of collision around the Korean Peninsula still remains under debate. In particular, the collision location in the Yellow Sea is unclear due to limitation in physical accessibility by presence of oceanic environment and national borders. We investigate seismic features including seismicity, focal mechanism solutions and ambient stress fields around the Yellow Sea, and identify the collision location in the Yellow Sea. The focal mechanism solutions are determined by the waveform inversion and seismic wave polarity analyses. The representative ambient stress fields are induced by interpolating individual P and T axes of single events. Compared to the southeastern China, Yellow Sea and Korean Peninsula, high seismicity is found in the northeastern China. The ambient stress field around the Yellow Sea displays ENE-WSW compressional direction, which is consistently observed in the eastern China and Korean Peninsula. The strike-slip faulting events are typically expected in the eastern China, Yellow Sea and Korean Peninsula which belong to the intraplate zone. However, unusual normal faulting events with ENE-WSW directional strikes are observed in a narrow region between the Shandong Peninsula (eastern China) and the central Korean Peninsula. The observation suggests that the collision belt is extended to the Korean Peninsula across the Yellow Sea. The normal faulting region around the Yellow Sea corresponds to the region that experienced the paleo-tectonic evolution. Moderate to large earthquakes may occur in such region due to the reverse activation of the paleo-tectonic structures by current tectonic forces in the future.

  16. Land subsidence and relative sea-level rise in the southern Chesapeake Bay region

    USGS Publications Warehouse

    Eggleston, Jack; Pope, Jason

    2013-01-01

    The southern Chesapeake Bay region is experiencing land subsidence and rising water levels due to global sea-level rise; land subsidence and rising water levels combine to cause relative sea-level rise. Land subsidence has been observed since the 1940s in the southern Chesapeake Bay region at rates of 1.1 to 4.8 millimeters per year (mm/yr), and subsidence continues today. This land subsidence helps explain why the region has the highest rates of sea-level rise on the Atlantic Coast of the United States. Data indicate that land subsidence has been responsible for more than half the relative sea-level rise measured in the region. Land subsidence increases the risk of flooding in low-lying areas, which in turn has important economic, environmental, and human health consequences for the heavily populated and ecologically important southern Chesapeake Bay region. The aquifer system in the region has been compacted by extensive groundwater pumping in the region at rates of 1.5- to 3.7-mm/yr; this compaction accounts for more than half of observed land subsidence in the region. Glacial isostatic adjustment, or the flexing of the Earth’s crust in response to glacier formation and melting, also likely contributes to land subsidence in the region.

  17. The analysis of temporal variations in regional models of the Sargasso Sea from GEOS-3 altimetry

    NASA Technical Reports Server (NTRS)

    Mather, R. S.; Coleman, R.; Hirsch, B.

    1978-01-01

    The dense coverage of short pulse mode GEOS-3 altimeter data in the western North Atlantic provides a basis for studying time variations in the sea surface heights in the Sargasso Sea. Two techniques are utilized: the method of regional models, and the analysis of overlapping passes. An 88 percent correlation is obtained between the location of cyclonic eddies obtained from infrared imagery and sea surface height minima in the altimeter models. This figure drops to 59 percent in the case of correlations with maxima and minima of surface temperature fields. The analysis of overlapping passes provides a better picture of instantaneous sea state through wavelengths greater than 30 km. The variability of the Sargasso Sea through wavelengths between 150 km and 5000 km is estimated at + or - 28 cm. This value is in reasonable agreement with oceanographic estimates and is compatible with the eddy kinetic energy of a wind driven circulation.

  18. Contaminants and sea ducks in Alaska and the circumpolar region

    USGS Publications Warehouse

    Henny, Charles J.; Rudis, Deborah D.; Roffe, Thomas J.; Robinson-Wilson, Everett

    1995-01-01

    We review nesting sea duck population declines in Alaska during recent decades and explore the possibility that contaminants may be implicated. Aerial surveys of the surf scoter (Melanitta perspicillata), white-winged scoter (M. fusca), black scoter (M. nigra), oldsquaw (Clangula hyemalis), spectacled eider (Somateria fischeri), and Steller's eider (Polysticta stelleri) show long-term breeding population declines, especially the latter three species. The spectacled eider was recently classified threatened under the Endangered Species Act. In addition, three other diving ducks, which commonly winter in coastal areas, have declined from unknown causes. Large die-offs of all three species of scoters during molt, a period of high energy demand, were documented in August 1990, 1991, and 1992 at coastal reefs in southeastern Alaska. There was no evidence of infectious diseases in those scoters. The die-offs may or may not be associated with the long-term declines. Many scoters had elevated renal concentrations of cadmium (high of 375 μg/g dry weight [dw]). Effects of cadmium in sea ducks are not well understood. Selenium concentrations in livers of nesting white-winged scoters were high; however, the eggs they laid contained less selenium than expected based on relationships for freshwater bird species. Histological evaluation found a high prevalence of hepatocellular vacuolation (49%), a degenerative change frequently associated with sublethal toxic insult. Cadmium and selenium mean liver concentrations were generally higher in those birds with more severe vacuolation; however, relationships were not statistically significant. We do not know if sea duck population declines are related to metals or other contaminants.

  19. Contaminants and sea ducks in Alaska and the circumpolar region.

    PubMed Central

    Henny, C J; Rudis, D D; Roffe, T J; Robinson-Wilson, E

    1995-01-01

    We review nesting sea duck population declines in Alaska during recent decades and explore the possibility that contaminants may be implicated. Aerial surveys of the surf scoter (Melanitta perspicillata), white-winged scoter (M. fusca), black scoter (M. nigra), oldsqaw (Clangula hyemalis), spectacled eider (Somateria fischeri), and Steller's eider (Polysticta stellei) show long-term breeding population declines, especially the latter three species. The spectacled eider was recently classified threatened under the Endangered Species Act. In addition, three other diving ducks, which commonly winter in coastal areas, have declined from unknown causes. Large die-offs of all three species of scoters during molt, a period of high energy demand, were documented in August 1990, 1991, and 1992 at coastal reefs in southeastern Alaska. There was no evidence of infectious diseases in those scoters. The die-offs may or may not be associated with the long-term declines. Many scoters had elevated renal concentrations of cadmium (high of 375 micrograms/g dry weight [dw]). Effects of cadmium in sea ducks are not well understood. Selenium concentrations in livers of nesting white-winged scoters were high; however, the eggs they laid contained less selenium than expected based on relationships for freshwater bird species. Histological evaluation found a high prevalence of hepatocellular vacuolation (49%), a degenerative change frequently associated with sublethal toxic insult. Cadmium and selenium mean liver concentrations were generally higher in those birds with more severe vacuolation; however, relationships were not statistically significant. We do not know if sea duck population declines are related to metals or other contaminants. PMID:7556023

  20. Contaminants and sea ducks in Alaska and the circumpolar region

    USGS Publications Warehouse

    Henny, C.J.; Rudis, D.D.; Roffe, T.J.; Robinson-Wilson, E.

    1995-01-01

    We review nesting sea duck population declines in Alaska during recent decades and explore the possibility that contaminants may be implicated. Aerial surveys of the surf scoter (Melanitta perspicillata) , white-winged scoter (M. fusca) , black scoter (M. nigra) , oldsquaw (Clangula hyemalis) , spectacled eider (Somateria fischeri) , and Steller's eider (Polysticta stelleri) show long-term breeding population declines, especially the latter three species. The spectacled eider was recently classified threatened under the Endangered Species Act. In addition, three other diving ducks, which commonly winter in coastal areas, have declined from unknown causes. Large die-offs of all three species of scoters during molt, a period of high energy demand, were documented in August 1990, 1991, and 1992 at coastal reefs in southeastern Alaska. There was no evidence of infectious diseases in those scoters. The die-offs may or may not be associated with the long-term declines. Many scoters had elevated renal concentrations of cadmium (high of 375 ?g/g dry weight [dw]). Effects of cadmium in sea ducks are not well understood. Selenium concentrations in livers of nesting white-winged scoters were high ; however, the eggs they laid contained less selenium than expected based on relationships for freshwater bird species. Histological evaluation found a high prevalence of hepatocellular vacuolation (49%) , a degenerative change frequently associated with sublethal toxic insult. Cadmium and selenium mean liver concentrations were generally higher in those birds with more severe vacuolation ; however, relationships were not statistically significant. We do not know if sea duck population declines are related to metals or other contaminants.

  1. Persistent organochlorine pesticides and polychlorinated biphenyls in air of the North Sea region and air-sea exchange.

    PubMed

    Mai, Carolin; Theobald, Norbert; Hühnerfuss, Heinrich; Lammel, Gerhard

    2016-12-01

    Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were studied to determine occurrence, levels and spatial distribution in the marine atmosphere and surface seawater during cruises in the German Bight and the wider North Sea in spring and summer 2009-2010. In general, the concentrations found in air are similar to, or below, the levels at coastal or near-coastal sites in Europe. Hexachlorobenzene and α-hexachlorocyclohexane (α-HCH) were close to phase equilibrium, whereas net atmospheric deposition was observed for γ-HCH. The results suggest that declining trends of HCH in seawater have been continuing for γ-HCH but have somewhat levelled off for α-HCH. Dieldrin displayed a close to phase equilibrium in nearly all the sampling sites, except in the central southwestern part of the North Sea. Here atmospheric deposition dominates the air-sea exchange. This region, close to the English coast, showed remarkably increased surface seawater concentrations. This observation depended neither on riverine input nor on the elevated abundances of dieldrin in the air masses of central England. A net depositional flux of p,p'-DDE into the North Sea was indicated by both its abundance in the marine atmosphere and the changes in metabolite pattern observed in the surface water from the coast towards the open sea. The long-term trends show that the atmospheric concentrations of DDT and its metabolites are not declining. Riverine input is a major source of PCBs in the German Bight and the wider North Sea. Atmospheric deposition of the lower molecular weight PCBs (PCB28 and PCB52) was indicated as a major source for surface seawater pollution.

  2. Interannual Arctic sea ice variability and associated winter weather patterns: A regional perspective for 1979-2014

    NASA Astrophysics Data System (ADS)

    Chen, Hans W.; Alley, Richard B.; Zhang, Fuqing

    2016-12-01

    Using Arctic sea ice concentration derived from passive microwave satellite observations in autumn and early winter over the 1979-2014 period, the Arctic region was objectively classified into several smaller regions based on the interannual sea ice variability through self-organizing map analyses. The trend in regional sea ice extent (RSIE) in each region was removed using an adaptive, nonlinear, and nonstationary method called Ensemble Empirical Mode Decomposition, which captures well the accelerating decline of Arctic RSIEs in recent decades. Although the linear trend in RSIE is negative in all regions in both seasons, there are marked differences in RSIE trends and variability between regions, with the largest negative trends found during autumn in the Beaufort Sea, the Barents-Kara Seas, and the Laptev-East Siberian Seas. Winter weather patterns associated with the nonlinearly detrended RSIEs show distinct features for different regions and tend to be better correlated with the autumn than early winter RSIE anomalies. Sea ice losses in the Beaufort Sea and the Barents-Kara Seas are both associated with a cooling of Eurasia, but in the former case the circulation anomaly is reminiscent of a Rossby wave train, whereas in the latter case the pattern projects onto the negative phase of the Arctic Oscillation. These results highlight the nonuniform changes in Arctic sea ice and suggest that regional sea ice variations may play a crucial role for the winter weather patterns.

  3. Tuberculosis in St. Petersburg and the Baltic Sea region.

    PubMed

    Samarina, Arina; Zhemkov, Vladimir; Zakharova, Olga; Hoffner, Sven

    2007-01-01

    Tuberculosis (TB) remains a global public health concern and challenges the national structures for infection control and health care, as well as international institutions, to develop and implement new strategies to control and combat this disease. In our report, we investigated the TB epidemiological situation in St. Petersburg and the countries around the Baltic Sea using national epidemiological statistics and epidemiological reports of international organizations, such as the WHO and Euro-TB. After the disintegration of the Soviet Union, a steep increase in tuberculosis was seen in the Russian Federation, St. Petersburg and the Baltic States, after which it stabilized at levels significantly higher compared to the Nordic countries. Moreover, the epidemiological situation in St. Petersburg and the Baltic States was aggravated by the emergence and spread of TB/HIV coinfection, as well as that of drug-resistant M. tuberculosis, which imposed further difficulties in gaining control of TB. During the studied period, the TB burden in neither St. Petersburg nor Baltic States has had a significant impact on the epidemiology in the low TB burden neighbouring countries around the Baltic Sea.

  4. The SeaDataNet data products: regional temperature and salinity historical data collections

    NASA Astrophysics Data System (ADS)

    Simoncelli, Simona; Coatanoan, Christine; Bäck, Orjan; Sagen, Helge; Scoy, Serge; Myroshnychenko, Volodymyr; Schaap, Dick; Schlitzer, Reiner; Iona, Sissy; Fichaut, Michele

    2016-04-01

    Temperature and Salinity (TS) historical data collections covering the time period 1900-2013 were created for each European marginal sea (Arctic Sea, Baltic Sea, Black Sea, North Sea, North Atlantic Ocean and Mediterranean Sea) within the framework of SeaDataNet2 (SDN) EU-Project and they are now available as ODV collections through the SeaDataNet web catalog at http://sextant.ifremer.fr/en/web/seadatanet/. Two versions have been published and they represent a snapshot of the SDN database content at two different times: V1.1 (January 2014) and V2 (March 2015). A Quality Control Strategy (QCS) has been developped and continuously refined in order to improve the quality of the SDN database content and to create the best product deriving from SDN data. The QCS was originally implemented in collaboration with MyOcean2 and MyOcean Follow On projects in order to develop a true synergy at regional level to serve operational oceanography and climate change communities. The QCS involved the Regional Coordinators, responsible of the scientific assessment, the National Oceanographic Data Centers (NODC) and the data providers that, on the base of the data quality assessment outcome, checked and eventually corrected anomalies in the original data. The QCS consists of four main phases: 1) data harvesting from the central CDI; 2) file and parameter aggregation; 3) quality check analysis at regional level; 4) analysis and correction of data anomalies. The approach is iterative to facilitate the upgrade of SDN database content and it allows also the versioning of data products with the release of new regional data collections at the end of each QCS loop. SDN data collections and the QCS will be presented and the results summarized.

  5. The distribution and composition of deep-sea microbenthos in a bathyal region of the western Coral Sea

    NASA Astrophysics Data System (ADS)

    Alongi, Daniel M.

    1987-07-01

    The distribution and composition of bathyal (298-1610 m) microbenthos were examined on the Queensland continental slope, the Coral Sea Plateau and the adjacent Queensland and Townsville troughs in the western Coral Sea. Two conspicuous changes in community composition were recorded: (1) ciliates were undetected below 700 m and (2) yeasts and yeast-like cells were undetected above 1150 m. Densities of flagellates decreased, whereas amoebae densities increased significantly with water depth. Densities of living Foraminifera ( overlinex = 56 cm-2) increased significantly from the continental slope to the adjacent troughs. Bacterial numbers ranged from 0.1 to 71.0 × 10 8 cells g -1 dry wt of sediment and decreased significantly with water depth. Chlorophyll a (0.0-19.0 μg g -1 dry wt) and phaeopigment (0.0-4.9 μg g -1 dry wt) concentrations suggest that phytodetritus is a major source of organic matter in this tropical region. Concentrations of organic carbon (0.22-0.52%) and nitrogen (<0.01-0.02%) were low compared to most other deep-sea sediments, with a shallow sediment depth distribution indicating little burial of organic matter. These findings, coupled with the presence of abundant protozoan populations (˜10 6 m -2), suggest the potential for rapid microbial activity and dentrital utilization in bathyal surface sediments of the western Coral Sea.

  6. Biogeography of the Lord Howe Rise region, Tasman Sea

    NASA Astrophysics Data System (ADS)

    Przeslawski, Rachel; Williams, Alan; Nichol, Scott L.; Hughes, Michael G.; Anderson, Tara J.; Althaus, Franziska

    2011-04-01

    The two principal aims of this study were to synthesise physical and biological information to characterise the Lord Howe Rise (LHR) region and to use recent survey collections of benthic invertebrates (mostly large benthic epifauna) to describe its biogeography at regional and sub-regional scales. The LHR region is large (1.95 million km 2), spans tropical and cool temperate latitudes (18.4 to 40.3°S), and is influenced by several ocean currents, notably the East Australian Current and the Tasman Front. Our analyses revealed that biological patterns were related to two groups of geomorphic morphotypes found in this topographically complex region: subdued bathymetric features (expansive soft sediment basins and plateaus) and raised bathymetric features (scattered seamounts, guyots, knolls, and pinnacles). Raised bathymetric features in the LHR region were more likely to support richer and more abundant epifaunal assemblages dominated by suspension feeding invertebrates on hard substrata compared to subdued features which were dominated by infauna and detritivores in soft sediments. However, this trend does not apply to all raised bathymetric features (e.g., Gifford Guyot), with variations in depth, elevation, latitude, and particularly substrata affected the composition of biological assemblages. In addition, some demersal fishes, ophiuroids, and other benthic invertebrates showed distinct north-south delineations that coincide with the influence of the Tasman Front and thermal gradients. While the lack of spatially- and temporally- replicated data in the region limits our interpretation of survey data, paleo-environmental processes and examples from other regions provide some indication of how dispersal influences migration, speciation, and endemism in the LHR region. Although our current knowledge is limited, it is hoped that this review will help inform future studies in the area, as equitable examination of biological, geological, and oceanographic

  7. Historical whaling records reveal major regional retreat of Antarctic sea ice

    NASA Astrophysics Data System (ADS)

    Cotté, Cédric; Guinet, Christophe

    2007-02-01

    Several studies have provided evidence of a reduction of the Antarctic sea ice extent. However, these studies were conducted either at a global scale or at a regional scale, and possible inter-regional differences were not analysed. Using the long-term whaling database we investigated circum-Antarctic changes in summer sea ice extent from 1931 to 1987. Accounting for bias inherent in the whaling method, this analysis provides new insight into the historical ice edge reconstruction and inter-regional differences. We highlight a reduction of the sea ice extent occurring in the 1960s, mainly in the Weddell sector where the change ranged from 3° to 7.9° latitude through summer. Although the whaling method may not be appropriate for detecting fine-scale change, these results provide evidence for a heterogeneous circumpolar change of the sea ice extent. The shift is temporally and spatially consistent with other environmental changes detected in the Weddell sector and also with a shift in the Southern Hemisphere annular mode. The large reduction of the sea ice extent has probably influenced the ecosystem of the Weddell Sea, particularly the krill biomass.

  8. The interpretation of crustal dynamics data in terms of plate interactions and active tectonics of the Anatolian Plate and surrounding regions in the Middle East

    NASA Technical Reports Server (NTRS)

    Toksoz, M. Nafi

    1987-01-01

    The primary effort in this study during the past year has been directed along two separate lines: (1) expanding finite element models to include the entire Anatolian plate, the Aegean Sea and the Northeastern Mediterranean Sea, and (2) investigating the relationship between fault geometry and earthquake activity for the North Anatolian and similar strike-slip faults (e.g., San Andreas Fault). Both efforts are designed to provide an improved basis for interpreting the Crustal Dynamics measurements NASA has planned for this region. The initial phases of both investigations have been completed and the results are being prepared for publication. These investigations are described briefly.

  9. Holocene deposits in the Mangyshlak Peninsula, North Caspian Sea region

    NASA Astrophysics Data System (ADS)

    Bezrodnykh, Yu. P.; Deliya, S. V.; Romanyuk, B. F.; Fedorov, V. I.; Sorokin, V. M.; Luksha, V. L.

    2014-07-01

    Comprehensive analysis of the data of high-precision seismoacoustic profiling, drilling and sampling of deposits using seabed corers, biostratigraphic studies, and radiocarbon age data was performed for the first time for Mangyshlak sediments in several bottom sites of the North Caspian. It was found that the Mangyshlak sediments comprise numerous linearly stretched depressions of 5-10 m in depth (morphologically similar to modern substeppe ilmen areas in the Volga River delta), which are covered by the Novocaspian sedimentary cover, and river incisions (among them the largest Volga River valley). In addition, the Mangyshlak sediments comprise the deltaic alluvial fans of different sizes along the shelf zone of the North Caspian. Analysis of mollusks and biogenic remains indicates that accumulation of the Mangyshlak sediments occurred in freshwater and slightly salty water environments under various hydrodynamic and hydrochemical conditions. According to radiocarbon dating of organic matter, the Mangyshlak sediments formed during sea regression in the range of 10-8 ka (isotopic age) or 11.5-8.5 ka (calendar age). Several types of sediments are distinguished: clayey-carbonate sediments, enriched with organic matter up to the formation of sapropel and peat, accumulated at the lowest sea level; weakly calcareous silty-clayey silts, formed during the subsequent intense filling of paleodepressions with terrigenous material. The features of the mineral composition of sediments are as follows: polymineral composition of clayey material with a high proportion of hydromica and disordered mixed-layered formations, a high content of minerals of the epidote group, amphiboles, and other accessory minerals. All of this indicates a genetic relationship between the Mangyshlak sediments and the Volga terrigenous material.

  10. BIAS: A Regional Management of Underwater Sound in the Baltic Sea.

    PubMed

    Sigray, Peter; Andersson, Mathias; Pajala, Jukka; Laanearu, Janek; Klauson, Aleksander; Tegowski, Jaroslaw; Boethling, Maria; Fischer, Jens; Tougaard, Jakob; Wahlberg, Magnus; Nikolopoulos, Anna; Folegot, Thomas; Matuschek, Rainer; Verfuss, Ursula

    2016-01-01

    Management of the impact of underwater sound is an emerging concern worldwide. Several countries are in the process of implementing regulatory legislations. In Europe, the Marine Strategy Framework Directive was launched in 2008. This framework addresses noise impacts and the recommendation is to deal with it on a regional level. The Baltic Sea is a semienclosed area with nine states bordering the sea. The number of ships is one of the highest in Europe. Furthermore, the number of ships is estimated to double by 2030. Undoubtedly, due to the unbound character of noise, an efficient management of sound in the Baltic Sea must be done on a regional scale. In line with the European Union directive, the Baltic Sea Information on the Acoustic Soundscape (BIAS) project was established to implement Descriptor 11 of the Marine Strategy Framework Directive in the Baltic Sea region. BIAS will develop tools, standards, and methodologies that will allow for cross-border handling of data and results, measure sound in 40 locations for 1 year, establish a seasonal soundscape map by combining measured sound with advanced three-dimensional modeling, and, finally, establish standards for measuring continuous sound. Results from the first phase of BIAS are presented here, with an emphasis on standards and soundscape mapping as well as the challenges related to regional handling.

  11. Interannual and regional variability of ecosystem dynamics in the Black Sea

    NASA Astrophysics Data System (ADS)

    Fach, Bettina A.; Cannaby, Heather; Dorofeyev, Viktor L.; Kubryakov, Alexander I.; Salihoglu, Baris; Korotaev, Gennady K.; Oguz, Temel; Kideys, Ahmet E.

    2013-04-01

    A three-dimensional hydrodynamic ecosystem model developed for the Black Sea was used to investigate the influence of anthropogenic drivers on marine ecosystem functioning in the Black Sea with a special focus on regional differences. Data from the ECMWF 40 Year Re-analysis global atmospheric circulation model (ERA-40) were used to force a coupled hydrodynamic ecosystem model (BIMS) for a hindcast simulation from 1980-2000. Model skill was assessed by model comparisons with SeaWiFS surface chlorophyll distributions. We study the regional differences the introduction of invasive comb jelly Mnemiopsis leidyi has on modeled ecosystem dynamics as well as the regional influence of changing river nutrient loads on ecosystem dynamics. We can demonstrate clearly that the appearance of M. Leidyi changes ecosystem functioning through exerting grazing pressure on zooplankton and thereby changing the seasonal cycle of phytoplankton and zooplankton species significantly. On the north-western shelf this effect is less pronounced than in the southeast Black Sea, where zooplankton is grazed down more heavily, allowing for higher phytoplankton biomass. In addition, the Black Sea ecosystem shows strong regional nitrate limitation, and high sensitivity to increased eutrophication: A 50% increase in nutrient loading causes a 48% increase in primary production in the eastern regions of the Black Sea, while the north-western shelf reacts more moderately. Despite an increase in primary production, chlorophyll-a concentrations typically respond weakly to changes in nitrate availability. This indicates that increased grazing closely mirrors an increase in productivity. This is confirmed by an increase in zooplankton biomass. It is important to note that for this reason simulated chlorophyll concentration is not a good indicator of eutrophication in the Black Sea. The reduction in the productivity of the entire Black Sea system associated with a reduction in riverine nutrient loadings is

  12. Using existing data and focused surveys to highlight Cuvier's beaked whales favourable areas: a case study in the central Tyrrhenian Sea.

    PubMed

    Gannier, Alexandre

    2011-01-01

    This study focuses on the necessary elements to implement strategic mitigation in order to avoid Cuvier's beaked whale (CBW) strandings linked to intense sound sources, such as military active sonars, in the Mediterranean Sea. A careful review of stranding data and the analysis of existing survey results are required to highlight the main characters of the species regional distribution. Focused and repeated surveys are needed to confirm that possible favourable areas, such as the Balearic, Tyrrhenian or Aegean Seas, are really favourable CBW habitats. These surveys should be carried out with sea states 0 to 1 in order to minimize the risk of false absence data. Among the regions of interest, the central Tyrrhenian Sea was surveyed with a 12 m sailboat in 2007 and 2008. With 907 km of effective effort, a mean sighting rate of 1.9 CBW school/100 km was obtained, which is amongst the highest densities recorded in the Mediterranean.

  13. Pelagic-benthic coupling and diagenesis of nucleic acids in a deep-sea continental margin and an open-slope system of the Eastern Mediterranean.

    PubMed

    Dell'anno, Antonio; Corinaldesi, Cinzia; Stavrakakis, Spyros; Lykousis, Vasilis; Danovaro, Roberto

    2005-10-01

    Downward fluxes of nucleic acids adsorbed onto settling particles play a key role in the supply of organic phosphorus and genetic material to the ocean interior. However, information on pelagic-benthic coupling, diagenesis, and processes controlling nucleic acid preservation in deep-sea sediments is practically nonexistent. In this study, we compared nucleic acid fluxes, sedimentary DNA and RNA concentrations, and the enzymatically hydrolyzable fraction of DNA in a bathyal continental margin (North Aegean Sea) and an open-sea system (South Aegean Sea) of the Eastern Mediterranean. The two systems displayed contrasting patterns of nucleic acid fluxes, which increased significantly with depth in the North Aegean Sea and decreased with depth in the South Aegean Sea. These results suggest that in continental margin and open-ocean systems different processes control the nucleic acid supply to the sea floor. Differences in nucleic acid fluxes were reflected by nucleic acid concentrations in the sediments, which reached extremely high values in the North Aegean Sea. In this system, a large fraction of DNA may be buried, as suggested by the large fraction of DNA resistant to nuclease degradation and by estimates of burial efficiency (ca. eight times higher in the North than in the South Aegean Sea). Overall, the results reported here suggest that the preservation of DNA in deeper sediment layers may be favored in benthic systems characterized by high sedimentation rates.

  14. Condition of groundfish resources of the eastern Bering Sea and Aleutian Islands region in 1982

    SciTech Connect

    Bakkala, R.G.; Low, L.; Ito, D.H.; Narita, R.E.; Ronholt, L.L.

    1983-03-01

    This report contains an assessment of the condition of groundfish and squid in the eastern Bering Sea and Aleutian Islands region through 1982. The assessments are based on species-by-species analyses of the data collected from the commercial fishery and research vessel surveys. Most of the resources in the Bering Sea-Aleutians management region are in good condition, including walleye pollock, Pacific cod, the flatfishes, and Atka mackerel. Pacific cod and yellowfin sole are in excellent condition and at historic high levels of abundance.

  15. Studying luminescent characteristics of the specific surfactants in various regions of the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Drozdowska, V.; Darecki, M.; Gutowska, D.; Makuch, P.; Kowalczyk, J.; Strzałkowska, A.; Petelski, T.; Piskozub, J.

    2012-04-01

    The sea surface layer is the interface between the atmosphere and marine environment, where there are a variety of physical, biological and chemical processes that contribute to accumulation and exchange of surface-active-agents (surfactants). At the same time the dynamic properties of the water surface (surface wave spectrum) and fluxes (especially in gas exchange and production of marine aerosol) and even the apparent and real optical properties of seawater are affected by the surfactants gathered on the sea surface. Moreover, the presence of the surface film may restrict the supply of light energy into the depths of the sea. The study was conducted in different regions of the Baltic Sea which also assessed the impact of external environment (estuaries, vicinity of the ports and shipping routs) on the marine environment. The primary scientific objectives were: - to investigate the variability of luminescent properties of surfactants and organic matter contained in the surface film and layer of the sea from the results of spectrophotometric studies. - to find any special surfactants (characterized by luminescent properties) occurring in certain regions of the Baltic. The practical aim was to answer the question whether and to what extent changes in luminescence properties of organic matter contained in the film and the layer depend on the biological activity of the basin and how they affect the water leaving radiance remotely measured over the surface of the sea.

  16. Response of the Arabian Sea to global warming and associated regional climate shift.

    PubMed

    Kumar, S Prasanna; Roshin, Raj P; Narvekar, Jayu; Kumar, P K Dinesh; Vivekanandan, E

    2009-12-01

    The response of the Arabian Sea to global warming is the disruption in the natural decadal cycle in the sea surface temperature (SST) after 1995, followed by a secular warming. The Arabian Sea is experiencing a regional climate-shift after 1995, which is accompanied by a five fold increase in the occurrence of "most intense cyclones". Signatures of this climate-shift are also perceptible over the adjacent landmass of India as: (1) progressively warmer winters, and (2) decreased decadal monsoon rainfall. The warmer winters are associated with a 16-fold decrease in the decadal wheat production after 1995, while the decreased decadal rainfall was accompanied by a decline of vegetation cover and increased occurrence of heat spells. We propose that in addition to the oceanic thermal inertia, the upwelling-driven cooling provided a mechanism that offset the CO(2)-driven SST increase in the Arabian Sea until 1995.

  17. Wintertime enhancements of sea salt aerosol in polar regions consistent with a sea ice source from blowing snow

    NASA Astrophysics Data System (ADS)

    Huang, Jiayue; Jaeglé, Lyatt

    2017-03-01

    Sea salt aerosols (SSA) are generated via air bubbles bursting at the ocean surface as well as by wind mobilization of saline snow and frost flowers over sea-ice-covered areas. The relative magnitude of these sources remains poorly constrained over polar regions, affecting our ability to predict their impact on halogen chemistry, cloud formation, and climate. We implement a blowing snow and a frost flower emission scheme in the GEOS-Chem global chemical transport model, which we validate against multiyear (2001-2008) in situ observations of SSA mass concentrations at three sites in the Arctic, two sites in coastal Antarctica, and from the 2008 ICEALOT cruise in the Arctic. A simulation including only open ocean emissions underestimates SSA mass concentrations by factors of 2-10 during winter-spring for all ground-based and ship-based observations. When blowing snow emissions are added, the model is able to reproduce observed wintertime SSA concentrations, with the model bias decreasing from a range of -80 to -34 % for the open ocean simulation to -2 to +9 % for the simulation with blowing snow emissions. We find that the frost flower parameterization cannot fully explain the high wintertime concentrations and displays a seasonal cycle decreasing too rapidly in early spring. Furthermore, the high day-to-day variability of observed SSA is better reproduced by the blowing snow parameterization. Over the Arctic (> 60° N) (Antarctic, > 60° S), we calculate that submicron SSA emissions from blowing snow account for 1.0 Tg yr-1 (2.5 Tg yr-1), while frost flower emissions lead to 0.21 Tg yr-1 (0.25 Tg yr-1) compared to 0.78 Tg yr-1 (1.0 Tg yr-1) from the open ocean. Blowing snow emissions are largest in regions where persistent strong winds occur over sea ice (east of Greenland, over the central Arctic, Beaufort Sea, and the Ross and Weddell seas). In contrast, frost flower emissions are largest where cold air temperatures and open leads are co-located (over the Canadian

  18. Satellite Altimetry-Based Sea Level at Global and Regional Scales

    NASA Astrophysics Data System (ADS)

    Ablain, M.; Legeais, J. F.; Prandi, P.; Marcos, M.; Fenoglio-Marc, L.; Dieng, H. B.; Benveniste, J.; Cazenave, A.

    2017-01-01

    Since the beginning of the 1990s, sea level is routinely measured using high-precision satellite altimetry. Over the past 25 years, several groups worldwide involved in processing the satellite altimetry data regularly provide updates of sea level time series at global and regional scales. Here we present an ongoing effort supported by the European Space Agency (ESA) Climate Change Initiative Programme for improving the altimetry-based sea level products. Two main objectives characterize this enterprise: (1) to make use of ESA missions (ERS-1 and 2 and Envisat) in addition to the so-called `reference' missions like TOPEX/Poseidon and the Jason series in the computation of the sea level time series, and (2) to improve all processing steps in order to meet the Global Climate Observing System (GCOS) accuracy requirements defined for a set of 50 Essential Climate Variables, sea level being one of them. We show that improved geophysical corrections, dedicated processing algorithms, reduction of instrumental bias and drifts, and careful linkage between missions led to improved sea level products. Regarding the long-term trend, the new global mean sea level record accuracy now approaches the GCOS requirements (of 0.3 mm/year). Regional trend uncertainty has been reduced by a factor of 2, but orbital and wet tropospheric corrections errors still prevent fully reaching the GCOS accuracy requirement. Similarly at the interannual time scale, the global mean sea level still displays 2-4 mm errors that are not yet fully understood. The recent launch of new altimetry missions (Sentinel-3, Jason-3) and the inclusion of data from currently flying missions (e.g., CryoSat, SARAL/AltiKa) may provide further improvements to this important climate record.

  19. Yemeni Red Sea and Gulf of Aden petroleum geology and regional geophysical evaluation

    SciTech Connect

    Al-Sanabani, M.; Said, F.M. )

    1991-08-01

    The World Bank-executed Red Sea/Gulf of Aden Regional Hydrocarbon Study Project was organized to synthesize data on the Red Sea and Gulf of Aden basins. The study of Yemeni Red Sea and Gulf of Aden was based on public-domain exploration data, published information, and data released by operating companies. These included reports, sections, and wireline logs from 15 well, samples from 15 wells for biostratigraphic analysis, and samples from 11 wells for geochemical analysis. Interpretation was carried out on 7,419 line-km of seismic data selected from a grid of 21,623 line-km of data. Four horizons were identified on a regional basis in the Red Sea area, including the sea floor, top, and near base of middle to upper Miocene evaporites, and approximate acoustic basement, as well as equivalent series in the Gulf of Aden. Bathymetric, structure-contour, and interval isopach maps were prepared using digitized picks from the interpreted seismic. Examples of each of these interpreted results will be on display. The results show that the Yemeni Red Sea is similar to the better known, productive Gulf of Suez in its tectonic evolution, and in its Miocene to Holocene stratigraphic sequence. Surface shows on the east side of the southern Red Sea in the Yemeni part of the basin suggest that this area contain the necessary elements for several attractive petroleum plays. The Yemeni Red Sea appears to contain the necessary elements for an attractive petroleum potential. The Yemeni Gulf of Aden, on the other hand, shows an attractive potential chiefly in pre-rift Mesozoic to Eocene units, with more limited potential in Oligocene to younger units.

  20. The implementation of sea ice model on a regional high-resolution scale

    NASA Astrophysics Data System (ADS)

    Prasad, Siva; Zakharov, Igor; Bobby, Pradeep; McGuire, Peter

    2015-09-01

    The availability of high-resolution atmospheric/ocean forecast models, satellite data and access to high-performance computing clusters have provided capability to build high-resolution models for regional ice condition simulation. The paper describes the implementation of the Los Alamos sea ice model (CICE) on a regional scale at high resolution. The advantage of the model is its ability to include oceanographic parameters (e.g., currents) to provide accurate results. The sea ice simulation was performed over Baffin Bay and the Labrador Sea to retrieve important parameters such as ice concentration, thickness, ridging, and drift. Two different forcing models, one with low resolution and another with a high resolution, were used for the estimation of sensitivity of model results. Sea ice behavior over 7 years was simulated to analyze ice formation, melting, and conditions in the region. Validation was based on comparing model results with remote sensing data. The simulated ice concentration correlated well with Advanced Microwave Scanning Radiometer for EOS (AMSR-E) and Ocean and Sea Ice Satellite Application Facility (OSI-SAF) data. Visual comparison of ice thickness trends estimated from the Soil Moisture and Ocean Salinity satellite (SMOS) agreed with the simulation for year 2010-2011.

  1. Residence times in shallow waters help explain regional differences in Wadden Sea eutrophication

    NASA Astrophysics Data System (ADS)

    Schwichtenberg, Fabian; Callies, Ulrich; van Beusekom, Justus E. E.

    2016-11-01

    Regional variations in eutrophication levels of tidal basins in the Wadden Sea can be caused by external factors, like organic matter import, and internal factors like the morphology and hydrodynamics of the receiving tidal basin. For instance, benthic nutrients from remineralized organic matter may be more concentrated in shallow basins or diluted in basins with high exchange rates. In addition, the location of a monitoring station may determine which basin-specific water masses are actually observed. In the present paper a hydrodynamic intertidal imprint (IMP) is estimated for ten stations in various tidal basins of the Wadden Sea. The fraction of time water masses spent in intertidal areas prior to observation is calculated by linking the Lagrangian transport module PELETS to already existing hourly reconstructions of currents between 1959 and 2003. Irrespective of water depth, additional calculations of mean residence times (MRT) in the Wadden Sea indicate whether, in the case of low IMP values, water masses originate from coastal areas or tidal channels. Results show distinct regional differences, with highest values in the eastern part of the Dutch sector of the southern Wadden Sea (IMP=77%, MRT=99%) and lowest values in the German/Danish sector of the northern Wadden Sea (IMP=1.1%, MRT=21%). The IMP correlates positively with observed nutrient levels (R2=0.83). Evidently, this residence time-based intertidal signal is pivotal in explaining regional variations in eutrophication levels revealed by long-term comparative data from different monitoring stations.

  2. Residence times in shallow waters help explain regional differences in Wadden Sea eutrophication

    NASA Astrophysics Data System (ADS)

    Schwichtenberg, Fabian; Callies, Ulrich; van Beusekom, Justus E. E.

    2017-04-01

    Regional variations in eutrophication levels of tidal basins in the Wadden Sea can be caused by external factors, like organic matter import, and internal factors like the morphology and hydrodynamics of the receiving tidal basin. For instance, benthic nutrients from remineralized organic matter may be more concentrated in shallow basins or diluted in basins with high exchange rates. In addition, the location of a monitoring station may determine which basin-specific water masses are actually observed. In the present paper a hydrodynamic intertidal imprint (IMP) is estimated for ten stations in various tidal basins of the Wadden Sea. The fraction of time water masses spent in intertidal areas prior to observation is calculated by linking the Lagrangian transport module PELETS to already existing hourly reconstructions of currents between 1959 and 2003. Irrespective of water depth, additional calculations of mean residence times (MRT) in the Wadden Sea indicate whether, in the case of low IMP values, water masses originate from coastal areas or tidal channels. Results show distinct regional differences, with highest values in the eastern part of the Dutch sector of the southern Wadden Sea (IMP=77%, MRT=99%) and lowest values in the German/Danish sector of the northern Wadden Sea (IMP=1.1%, MRT=21%). The IMP correlates positively with observed nutrient levels (R2=0.83). Evidently, this residence time-based intertidal signal is pivotal in explaining regional variations in eutrophication levels revealed by long-term comparative data from different monitoring stations.

  3. Validation of a regional Indonesian Seas model based on a comparison between model and INSTANT transports

    NASA Astrophysics Data System (ADS)

    Rosenfield, D.; Kamenkovich, V.; O'Driscoll, K.; Sprintall, J.

    2010-08-01

    The International Nusantara Stratification and Transport (INSTANT) program measured currents through multiple Indonesian Seas passages simultaneously over a three-year period (from January 2004 to December 2006). The Indonesian Seas region has presented numerous challenges for numerical modelers — the Indonesian Throughflow (ITF) must pass over shallow sills, into deep basins, and through narrow constrictions on its way from the Pacific to the Indian Ocean. As an important region in the global climate puzzle, a number of models have been used to try and best simulate this throughflow. In an attempt to validate our model, we present a comparison between the transports calculated from our model and those calculated from the INSTANT in situ measurements at five passages within the Indonesian Seas (Labani Channel, Lifamatola Passage, Lombok Strait, Ombai Strait, and Timor Passage). Our Princeton Ocean Model (POM) based regional Indonesian Seas model was originally developed to analyze the influence of bottom topography on the temperature and salinity distributions in the Indonesian seas region, to disclose the path of the South Pacific Water from the continuation of the New Guinea Coastal Current entering the region of interest up to the Lifamatola Passage, and to assess the role of the pressure head in driving the ITF and in determining its total transport. Previous studies found that this model reasonably represents the general long-term flow (seasons) through this region. The INSTANT transports were compared to the results of this regional model over multiple timescales. Overall trends are somewhat represented but changes on timescales shorter than seasonal (three months) and longer than annual were not considered in our model. Normal velocities through each passage during every season are plotted. Daily volume transports and transport-weighted temperature and salinity are plotted and seasonal averages are tabulated.

  4. Two centuries of observed atmospheric variability and change over the North Sea region

    NASA Astrophysics Data System (ADS)

    Stendel, Martin; van den Besselaar, Else; Hannachi, Abdel; Kent, Elizabeth; Lefebvre, Christiana; Rosenhagen, Gudrun; Schenk, Frederik; van der Schrier, Gerard; Woollings, Tim

    2016-04-01

    In the upcoming North Sea Region Climate Change Assessment (NOSCCA), we present a synthesis of current knowledge about past, present and possible future climate change in the North Sea region. A climate change assessment from published scientific work has been conducted as a kind of regional IPCC report, and a book has been produced that will be published by Springer in 2016. In the framework of the NOSCCA project, we examine past and present studies of variability and changes in atmospheric variables within the North Sea region over the instrumental period, roughly the past 200 years, based on observations and reanalyses. The variables addressed in this presentation are large-scale circulation, pressure and wind, surface air temperature, precipitation and radiative properties (clouds, solar radiation, and sunshine duration). While air temperature over land, not unexpectedly, has increased everywhere in the North Sea region, with strongest trends in spring and in the north of the region, a precipitation increase has been observed in the north and a decrease in the south of the region. This pattern goes along with a north-eastward shift of storm tracks and is in agreement with climate model projections under enhanced greenhouse gas concentrations. For other variables, it is not obvious which part of the observed changes may be due to anthropogenic activities and which is internally forced. It remains also unclear to what extent atmospheric circulation over the North Sea region is influenced by distant factors, in particular Arctic sea-ice decline in recent decades. There are indications of an increase in the number of deep cyclones (but not in the total number of cyclones), while storminess since the late 19th century shows no robust trends. The persistence of circulation types appears to have increased over the last century, and consequently, there is an indication for 'more extreme' extreme events. However, changes in extreme weather events are difficult to assess

  5. Regional to Global Assessments of Phytoplankton Dynamics From The SeaWiFS Mission

    NASA Technical Reports Server (NTRS)

    Siegel, David; Behrenfeld, Michael; Maritorena, Stephanie; McClain, Charles R.; Antoine, David; Bailey, Sean W.; Bontempi, Paula S.; Boss, Emmanuel S.; Dierssen, Heidi M.; Doney, Scott C.; Eplee, R. E., Jr.; Evans, Robert H.; Feldman, Gene C.; Fields, Erik; Franz, Bryan A.; Kuring, Norman A.; Mengelt, Claudia; Nelson, Norman B.; Patt, Fred S.; Robinson, Wayne D.; Sarmiento, J. L.; Swan, C. M.; Werdell, Paul J.; Westberry, T. K.; Wilding, John G.; Yoder, J. A.

    2013-01-01

    Photosynthetic production of organic matter by microscopic oceanic phytoplankton fuels ocean ecosystems and contributes roughly half of the Earth's net primary production. For 13 years, the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) mission provided the first consistent, synoptic observations of global ocean ecosystems. Changes in the surface chlorophyll concentration, the primary biological property retrieved from SeaWiFS, have traditionally been used as a metric for phytoplankton abundance and its distribution largely reflects patterns in vertical nutrient transport. On regional to global scales, chlorophyll concentrations covary with sea surface temperature (SST) because SST changes reflect light and nutrient conditions. However, the oceanmay be too complex to be well characterized using a single index such as the chlorophyll concentration. A semi-analytical bio-optical algorithm is used to help interpret regional to global SeaWiFS chlorophyll observations from using three independent, well-validated ocean color data products; the chlorophyll a concentration, absorption by CDM and particulate backscattering. First, we show that observed long-term, global-scale trends in standard chlorophyll retrievals are likely compromised by coincident changes in CDM. Second, we partition the chlorophyll signal into a component due to phytoplankton biomass changes and a component caused by physiological adjustments in intracellular chlorophyll concentrations to changes in mixed layer light levels. We show that biomass changes dominate chlorophyll signals for the high latitude seas and where persistent vertical upwelling is known to occur, while physiological processes dominate chlorophyll variability over much of the tropical and subtropical oceans. The SeaWiFS data set demonstrates complexity in the interpretation of changes in regional to global phytoplankton distributions and illustrates limitations for the assessment of phytoplankton dynamics using chlorophyll

  6. The influence of regional Arctic sea-ice decline on stratospheric and tropospheric circulation

    NASA Astrophysics Data System (ADS)

    McKenna, Christine; Bracegirdle, Thomas; Shuckburgh, Emily; Haynes, Peter

    2016-04-01

    Arctic sea-ice extent has rapidly declined over the past few decades, and most climate models project a continuation of this trend during the 21st century in response to greenhouse gas forcing. A number of recent studies have shown that this sea-ice loss induces vertically propagating Rossby waves, which weaken the stratospheric polar vortex and increase the frequency of sudden stratospheric warmings (SSWs). SSWs have been shown to increase the probability of a negative NAO in the following weeks, thereby driving anomalous weather conditions over Europe and other mid-latitude regions. In contrast, other studies have shown that Arctic sea-ice loss strengthens the polar vortex, increasing the probability of a positive NAO. Sun et al. (2015) suggest these conflicting results may be due to the region of sea-ice loss considered. They find that if only regions within the Arctic Circle are considered in sea-ice projections, the polar vortex weakens; if only regions outwith the Arctic Circle are considered, the polar vortex strengthens. This is because the anomalous Rossby waves forced in the former/latter scenario constructively/destructively interfere with climatological Rossby waves, thus enhancing/suppressing upward wave propagation. In this study, we investigate whether Sun et al.'s results are robust to a different model. We also divide the regions of sea-ice loss they considered into further sub-regions, in order to examine the regional differences in more detail. We do this by using the intermediate complexity climate model, IGCM4, which has a well resolved stratosphere and does a good job of representing stratospheric processes. Several simulations are run in atmosphere only mode, where one is a control experiment and the others are perturbation experiments. In the control run annually repeating historical mean surface conditions are imposed at the lower boundary, whereas in each perturbation run the model is forced by SST perturbations imposed in a specific

  7. A New Regional Bathymetry Map of the Amundsen Sea, West Antarctica

    NASA Astrophysics Data System (ADS)

    Nitsche, F. O.; Jacobs, S.; Gohl, K.; Gauger, S.; Larter, R. D.; Deen, T.

    2006-12-01

    The Amundsen Sea continental shelf is one of the remotest areas of coastal Antarctica, and was relatively unexplored until the late 1980s. Over the last two decades, however, it has increasingly become the focus of a strong interest in West Antarctic Ice Sheet (WAIS) sensitivity to warming and oceanographic changes on a range of timescales. One concern is that a change in the ocean circulation and/or properties, aided by deep glacial troughs in the sea floor, could be responsible for the reported thinning ice shelves and accelerating glaciers in this sector. This has potentially global implications as there is enough ice in the Amundsen Sea sector of the WAIS to raise global sea level by 1.5 m. Oceanographic and geological interest has led to several cruises, one result of which is that there is now sufficient bathymetric data to compile a fairly detailed regional map of the Amundsen continental shelf. We have combined the available multibeam and single beam bathymetry data from this region and created a new regional bathymetric map of the Amundsen Sea continental shelf and slope. We also integrated data from the BEDMAP project, the US Airborne Geophysical Survey of the Amundsen Sea Embayment, Antarctica (AGASEA) and the UK Basal Balance And Synthesis (BBAS) project for the surrounding land and ice-covered area. After cleaning the individual data sets we used a natural neighbor algorithm to interpolate between the existing data and create a grid at 5 km raster resolution. The most prominent regional feature is a series of separate trough systems along the inner shelf, which are aligned with present glaciers, separated by shallower ridges, and shoaling seaward. These troughs identify pathways of glacial flow during glaciations and now serve as conduits and reservoirs for warm Circumpolar Deep Water that contributes to high melting rates near ice shelf grounding lines.

  8. Timing and regional patterns of snowmelt on Antarctic sea ice from passive microwave satellite observations

    NASA Astrophysics Data System (ADS)

    Arndt, Stefanie; Willmes, Sascha; Dierking, Wolfgang; Nicolaus, Marcel

    2016-04-01

    The better understanding of temporal variability and regional distribution of surface melt on Antarctic sea ice is crucial for the understanding of atmosphere-ocean interactions and the determination of mass and energy budgets of sea ice. Since large regions of Antarctic sea ice are covered with snow during most of the year, observed inter-annual and regional variations of surface melt mainly represents melt processes in the snow. It is therefore important to understand the mechanisms that drive snowmelt, both at different times of the year and in different regions around Antarctica. In this study we combine two approaches for observing both surface and volume snowmelt by means of passive microwave satellite data. The former is achieved by measuring diurnal differences of the brightness temperature TB at 37 GHz, the latter by analyzing the ratio TB(19GHz)/TB(37GHz). Moreover, we use both melt onset proxies to divide the Antarctic sea ice cover into characteristic surface melt patterns from 1988/89 to 2014/15. Our results indicate four characteristic melt types. On average, 43% of the ice-covered ocean shows diurnal freeze-thaw cycles in the surface snow layer, resulting in temporary melt (Type A), less than 1% shows continuous snowmelt throughout the snowpack, resulting in strong melt over a period of several days (Type B), 19% shows Type A and B taking place consecutively (Type C), and for 37% no melt is observed at all (Type D). Continuous melt is primarily observed in the outflow of the Weddell Gyre and in the northern Ross Sea, usually 20 days after the onset of temporary melt. Considering the entire data set, snowmelt processes and onset do not show significant temporal trends. Instead, areas of increasing (decreasing) sea-ice extent have longer (shorter) periods of continuous snowmelt.

  9. Ultrasound imaging of the inguinal region of adult male loggerhead sea turtles (Caretta caretta).

    PubMed

    Pease, Anthony; Blanvillain, Gaëlle; Rostal, David; Owens, David; Segars, Al

    2010-03-01

    The biology and reproductive anatomy of male loggerhead sea turtles (Caretta caretta) have been difficult to study. The principle method for evaluation of the coelomic cavity in both adult and juvenile male sea turtles is celioscopy. The purpose of this study was to describe the technique and structures seen when scanning the inguinal region of live, wild-caught, adult male loggerhead sea turtles and to compare these findings to those resulting from celioscopy and necropsy. Twenty-one adult male loggerhead sea turtles were collected by trawling in the Cape Canaveral shipping channel in April 2007. All turtles were placed in dorsal recumbency and imaged with a Sonosite 180 Vet Plus (Sonosite, Inc., Bothell, Washington 98021, USA) and a microconvex, 4-7-MHz curvilinear array probe. The inguinal region was divided into four quadrants: cranial, lateral, medial, and caudal. Celioscopy was performed on 13 turtles, and biopsies were obtained of the testes and the epididymides to confirm correct identification of the structures. In the cranial aspect of the inguinal region, the urinary bladder and large and small intestines were identified. In the lateral inguinal region, the lung and kidney were seen. In the medial aspect of the inguinal region, the testis and epididymis were routinely identified. In the caudal aspect of the inguinal region, the coxofemoral joint was seen. A small learning curve was required; however, correlation with celioscopy and biopsy showed that consistent, repeatable identification of caudal coelomic structures was easily achieved. Ultrasound provided an inexpensive, rapid, noninvasive method to evaluate the reproductive anatomy of live-captured, male loggerhead sea turtles.

  10. 75 FR 59687 - Proposed Information Collection; Comment Request; Alaska Region Bering Sea & Aleutian Islands...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-28

    ... Region Bering Sea & Aleutian Islands (BSAI) Crab Economic Data Reports AGENCY: National Oceanic and... communities and monitors the ``economic stability for harvesters, processors, and coastal communities.'' The Magnuson-Stevens Act provides specific guidance on the CR Program's mandatory economic data...

  11. Stability of the Black Sea Littoral Region: Focus on the Montreux Convention

    DTIC Science & Technology

    2012-04-27

    the countries of the BSLR and their immediate neighbors are home to immense amounts of crude oil, natural gas, wheat, corn, and barley ; with large...regional countries and Ukrainian combined grain exports (20% of world’s grains shipped from the Black Sea) ranked first and third in global barley and

  12. Recent Research in Black Sea Region on Assessment in Education (Review)

    ERIC Educational Resources Information Center

    Pipia, Ekaterine

    2016-01-01

    This article is written to inform educational community particularly in the respect of new tendencies in educational assessment and present a clear-cut picture of the recent studies conducted in the Black Sea Region. The review paper refers to the following countries: Georgia, Russia, Turkey and Ukraine. It stresses the prevalent approach detected…

  13. Regional Sea Level Changes Projected by the NASA/GISS Atmosphere-Ocean Model

    NASA Technical Reports Server (NTRS)

    Russell, Gary L.; Gornitz, Vivien; Miller, James R.

    1999-01-01

    Sea level has been rising for the past century, and inhabitants of the Earth's coastal regions will want to understand and predict future sea level changes. In this study we present results from new simulations of the Goddard Institute for Space Studies (GISS) global atmosphere-ocean model from 1950 to 2099. Model results are compared with observed sea level changes during the past 40 years at 17 coastal stations around the world. Using observed levels of greenhouse gases between 1950 and 1990 and a compounded 0.5% annual increase in Co2 after 1990, model projections show that global sea level measured from 1950 will rise by 61 mm in the year 2000, by 212 mm in 2050, and by 408 mm in 2089. By 2089, two thirds of the global sea level rise will be due to thermal expansion and one third will be due to ocean mass changes. The spatial distribution of sea level rise is different than that projected by rigid lid ocean models.

  14. Foraminiferal stable isotope constraints on salinity changes in the deglacial and early Holocene Baltic Sea region

    NASA Astrophysics Data System (ADS)

    Quintana Krupinski, Nadine; Filipsson, Helena; Bokhari-Friberg, Yasmin; Knudsen, Karen-Luise; Mackensen, Andreas; Groeneveld, Jeroen; Austin, William

    2015-04-01

    The northern European Baltic Sea shows evidence of strong coupling with North Atlantic climate over recent glacial-interglacial cycles, but existing climate proxy evidence from regional sediment records suggest that the coupling may occur through non-linear processes. High-resolution regional climate records in Europe and from the Baltic Sea are critical for evaluating this coupling and the regional sensitivity to North Atlantic and global climate signals. However, evaluating the drivers and mechanisms of proposed links between the North Atlantic and Baltic Sea climate has often been hampered by a lack of long, continuous, high-resolution climate records from this area. New high-resolution sediment cores collected by IODP/ECORD Expedition 347 (Baltic Sea Paleoenvironment) allow such records to be generated, including foraminiferal geochemistry records of Baltic Sea hydrographic conditions during the most recent deglaciation and early Holocene (~19-7 cal. ka). The dramatic changes in salinity, sea level, circulation, temperature, and oxygenation during this period, e.g. through massive meltwater release from proglacial lakes and the early Holocene inundation of the Baltic by seawater highlight these non-linear links between the Baltic and North Atlantic. This work uses benthic foraminiferal stable isotope records (δ18O and δ13C) from sites in the western Baltic (M0059, Lillebælt, early Holocene marine stage (Littorina Sea)) and Kattegat (M0060, Anholt, deglaciation) to constrain salinity changes during these intervals. Because of the dramatic changes in salinity this region experiences today and during the study periods, oxygen isotope records (δ18O) here primarily reflect a signal of changing salinity, with a reduced temperature effect. Early δ18O results from the western Baltic (M0059) show a trend of declining δ18O/salinity during the first several kyr of the Littorina Sea stage, in agreement with previous work indicating declining salinity due to gradual

  15. Global and regional sea level change during the 20th century

    NASA Astrophysics Data System (ADS)

    Wenzel, Manfred; Schröter, Jens

    2014-11-01

    Sea level variations prior to the launch of satellite altimeters are estimated by analyzing historic tide gauge records. Recently, a number of groups have reconstructed sea level by applying EOF techniques to fill missing observations. We complement this study with alternative methods. In a first step gaps in 178 records of sea level change are filled using the pattern recognition capabilities of artificial neural networks. Afterward satellite altimetry is used to extrapolate local sea level change to global fields. Patterns of sea level change are compared to prior studies. Global mean sea level change since 1900 is found to be 1.77±0.38 mm yr-1 on average. Local trends are essentially positive with the highest values found in the western tropical Pacific and in the Indian Ocean east of Madagascar where it reaches about +6 mm yr-1. Regions with negative trends are spotty with a minimum value of about -2 mm yr-1 south of the Aleutian Islands. Although the acceleration found for the global mean, +0.0042 ± 0.0092 mm yr-2, is not significant, local values range from -0.1 mm yr-2 in the central Indian Ocean to +0.1 mm yr-2 in the western tropical Pacific and east of Japan. These extrema are associated with patterns of sea level change that differ significantly from the first half of the analyzed period (i.e., 1900-1950) to the second half (1950-2000). We take this as an indication of long period oceanic processes that are superimposed to the general sea level rise.

  16. Interannual and Regional Variability of Southern Ocean Snow on Sea Ice and its Correspondence with Sea Ice Cover and Atmospheric Circulation Patterns

    NASA Technical Reports Server (NTRS)

    Markus, T.; Cavalieri, D. J.

    2006-01-01

    Snow depth on sea ice plays a critical role in the heat exchange between ocean and atmosphere because of its thermal insulation property. Furthermore, a heavy snow load on the relatively thin Southern Ocean sea-ice cover submerges the ice floes below sea level, causing snow-to-ice conversion. Snowfall is also an important freshwater source into the weakly stratified ocean. Snow depth on sea-ice information can be used as an indirect measure of solid precipitation. Satellite passive microwave data are used to investigate the interannual and regional variability of the snow cover on sea ice. In this study we make use of 12 years (1992-2003) of Special Sensor Microwave/Imager (SSM/I) radiances to calculate average monthly snow depth on the Antarctic sea-ice cover. The results show a slight increase in snow depth and a partial eastward propagation of maximum snow depths, which may be related to the Antarctic Circumpolar Wave.

  17. Regionally differentiated contribution of mountain glaciers and ice caps to future sea-level rise

    NASA Astrophysics Data System (ADS)

    Radić, Valentina; Hock, Regine

    2011-02-01

    The contribution to sea-level rise from mountain glaciers and ice caps has grown over the past decades. They are expected to remain an important component of eustatic sea-level rise for at least another century, despite indications of accelerated wastage of the ice sheets. However, it is difficult to project the future contribution of these small-scale glaciers to sea-level rise on a global scale. Here, we project their volume changes due to melt in response to transient, spatially differentiated twenty-first century projections of temperature and precipitation from ten global climate models. We conduct the simulations directly on the more than 120,000 glaciers now available in the World Glacier Inventory, and upscale the changes to 19 regions that contain all mountain glaciers and ice caps in the world (excluding the Greenland and Antarctic ice sheets). According to our multi-model mean, sea-level rise from glacier wastage by 2100 will amount to 0.124+/-0.037m, with the largest contribution from glaciers in Arctic Canada, Alaska and Antarctica. Total glacier volume will be reduced by 21+/-6%, but some regions are projected to lose up to 75% of their present ice volume. Ice losses on such a scale may have substantial impacts on regional hydrology and water availability.

  18. Temporal variations in regional models of the Sargasso Sea from GEOS-3 altimetry

    NASA Technical Reports Server (NTRS)

    Mather, R. S.; Coleman, R.; Hirsch, B.

    1980-01-01

    The paper considers temporal variations in regional models of the Sargasso sea from GEOS-3 telemetry. The methods of regional models and the analysis of overlapping passes are utilized, and short-wave maxima and minima in the regional surface models are examined for correlations with surface and remote sensed infrared temperature data supplemented with subsurface expendable bathythermograph data (XBT). The analysis of overlapping passes provide a better picture of instanteneous sea surface height (SSH) variability through wavelengths greater than 30 km. Correlation studies with cyclonic and anticyclonic ocean eddies from infrared imagery and XBT data indicate satisfactory agreement with equivalent SSH features 98% of the time if the time varying factors are allowed for.

  19. Sea surface temperature 1871-2099 in 38 cells in the Caribbean region.

    PubMed

    Sheppard, Charles; Rioja-Nieto, Rodolfo

    2005-09-01

    Sea surface temperature (SST) data with monthly resolution are provided for 38 cells in the Caribbean Sea and Bahamas region, plus Bermuda. These series are derived from the HadISST1 data set for historical time (1871-1999) and from the HadCM3 coupled climate model for predicted SST (1950-2099). Statistical scaling of the forecast data sets are performed to produce confluent SST series according to a now established method. These SST series are available for download. High water temperatures in 1998 killed enormous amounts of corals in tropical seas, though in the Caribbean region the effects at that time appeared less marked than in the Indo-Pacific. However, SSTs are rising in accordance with world-wide trends and it has been predicted that temperature will become increasingly important in this region in the near future. Patterns of SST rise within the Caribbean region are shown, and the importance of sub-regional patterns within this biologically highly interconnected area are noted.

  20. Separating regional and global sea level contributions with an inverse multi-sensor approach

    NASA Astrophysics Data System (ADS)

    Kusche, J.; Jensen, L.; Rietbroek, R.

    2012-12-01

    We quantify the effect of mass flux (ice sheets, glaciers, land water storage) and steric changes on long-term and seasonal regional and global sea level variability. We perform a joint inversion with GRACE time-variable gravity and Jason-1/2 altimetric data and compare our results with those obtained with other methods. In this way, we are able to explain 1,45 mm/a of the 1,93 mm/a total sea level rise observed for 8/2002-7/2009. An inverse method to separate the temporal evolution of about 100 'fingerprints' of glacier and ice-sheet melting, thermal expansion, changes in catchment water storage and glacial isostatic adjustment from spaceborne gravity and altimetry data has been developed. Our method takes into account the effects of self-gravitation, elastic loading of the ocean bottom, and the response of Earth rotation to mass redistribution. For comparison, we also calculate the contributions of the individual catchments to sea level change from GRACE directly using a standard basin averaging method. While we find considerable differences between methods for catchment mass flux, GRACE-only results are quite robust in terms of global and regional sea level change. However, it turns out that adding Jason altimetry does provide valuable information in an inverse multi-sensor approach. In terms of global sea level rise, our results indicate, for example, a steric contribution of 0,35 mm/a in the considered time frame. Regionally, however, the contribution of ice sheets, glaciers, land water and steric changes displays strong variations. We will show results including error estimates for various regions.

  1. Tropical Marginal Seas: Priority Regions for Managing Marine Biodiversity and Ecosystem Function

    NASA Astrophysics Data System (ADS)

    McKinnon, A. David; Williams, Alan; Young, Jock; Ceccarelli, Daniela; Dunstan, Piers; Brewin, Robert J. W.; Watson, Reg; Brinkman, Richard; Cappo, Mike; Duggan, Samantha; Kelley, Russell; Ridgway, Ken; Lindsay, Dhugal; Gledhill, Daniel; Hutton, Trevor; Richardson, Anthony J.

    2014-01-01

    Tropical marginal seas (TMSs) are natural subregions of tropical oceans containing biodiverse ecosystems with conspicuous, valued, and vulnerable biodiversity assets. They are focal points for global marine conservation because they occur in regions where human populations are rapidly expanding. Our review of 11 TMSs focuses on three key ecosystems - coral reefs and emergent atolls, deep benthic systems, and pelagic biomes - and synthesizes, illustrates, and contrasts knowledge of biodiversity, ecosystem function, interaction between adjacent habitats, and anthropogenic pressures. TMSs vary in the extent that they have been subject to human influence - from the nearly pristine Coral Sea to the heavily exploited South China and Caribbean Seas - but we predict that they will all be similarly complex to manage because most span multiple national jurisdictions. We conclude that developing a structured process to identify ecologically and biologically significant areas that uses a set of globally agreed criteria is a tractable first step toward effective multinational and transboundary ecosystem management of TMSs.

  2. Tropical marginal seas: priority regions for managing marine biodiversity and ecosystem function.

    PubMed

    McKinnon, A David; Williams, Alan; Young, Jock; Ceccarelli, Daniela; Dunstan, Piers; Brewin, Robert J W; Watson, Reg; Brinkman, Richard; Cappo, Mike; Duggan, Samantha; Kelley, Russell; Ridgway, Ken; Lindsay, Dhugal; Gledhill, Daniel; Hutton, Trevor; Richardson, Anthony J

    2014-01-01

    Tropical marginal seas (TMSs) are natural subregions of tropical oceans containing biodiverse ecosystems with conspicuous, valued, and vulnerable biodiversity assets. They are focal points for global marine conservation because they occur in regions where human populations are rapidly expanding. Our review of 11 TMSs focuses on three key ecosystems-coral reefs and emergent atolls, deep benthic systems, and pelagic biomes-and synthesizes, illustrates, and contrasts knowledge of biodiversity, ecosystem function, interaction between adjacent habitats, and anthropogenic pressures. TMSs vary in the extent that they have been subject to human influence-from the nearly pristine Coral Sea to the heavily exploited South China and Caribbean Seas-but we predict that they will all be similarly complex to manage because most span multiple national jurisdictions. We conclude that developing a structured process to identify ecologically and biologically significant areas that uses a set of globally agreed criteria is a tractable first step toward effective multinational and transboundary ecosystem management of TMSs.

  3. Attributing causes of regional climate change in the Baltic Sea area

    NASA Astrophysics Data System (ADS)

    Bhend, Jonas; Gaillard-Lemdahl, Marie-José; Hansson, Hans-Christen

    2015-04-01

    Here we assess to what extent the effect of forcing mechanisms on the observed climate change in the Baltic Sea area can be detected. In particular, we assess the effect of factors causing large-scale warming (mainly anthropogenic greenhouse gases) and the regional effect of atmospheric aerosols and land-cover and land-use changes. Unfortunately, only very few targeted analyses for the Baltic catchment area are available at the moment, but findings at the regional scale are generally qualitatively consistent with global or hemispheric analyses. The observed warming in summer cannot be explained without human influence (in particular the warming effect of increasing atmospheric greenhouse gas concentrations). In other seasons and for other aspects of regional warming, findings are mixed or not significant as of yet. In addition, large-scale circulation and rainfall changes in the northern hemisphere and the Arctic have been detected to exceed natural internal variability. Other aspects of regional climate change including changes in storminess, snow properties, runoff and the changing physical properties of the Baltic Sea have not been formally attributed to human influence yet. Scientific understanding of the effect of aerosols on regional climate is still accumulating. It is likely that the major emission changes in Europe have had an effect on the climate in the Baltic region, the magnitude of which, however, is still unknown. Development of the modelling capability and targeted analyses are urgently needed to reduce the uncertainties related to the effect of aerosol changes on regional observed climate change. Historic deforestation and recent reforestation are the major anthropogenic land-cover changes affecting the Baltic Sea area. From all studies at hand it can be concluded that there is no evidence that anthropogenic land-cover change would be one of the forcings behind the recent warming in the Baltic region. However, past anthropogenic land-cover change

  4. Dynamic Triggering of Earthquakes in the Salton Sea Region of Southern California from Large Regional and Teleseismic Earthquakes

    NASA Astrophysics Data System (ADS)

    Doran, A.; Meng, X.; Peng, Z.; Wu, C.; Kilb, D. L.

    2010-12-01

    We perform a systematic survey of dynamically triggered earthquakes in the Salton Sea region of southern California using borehole seismic data recordings (2007 to present). We define triggered events as high-frequency seismic energy during large-amplitude seismic waves of distant earthquakes. Our mainshock database includes 26 teleseismic events (epicentral distances > 1000 km; Mw ≥ 7.5), and 8 regional events (epicentral distances 100 - 1000 km; Mw ≥ 5.5). Of these, 1 teleseismic and 7 regional events produce triggered seismic activity within our study region. The triggering mainshocks are not limited to specific azimuths. For example, triggering is observed following the 2008 Mw 6.0 Nevada earthquake to the north and the 2010 Mw7.2 Northern Baja California earthquake to the south. The peak ground velocities in our study region generated by the triggering mainshocks exceed 0.03 cm/s, which corresponds to a dynamic stress of ~2 kPa. This apparent triggering threshold is consistent with thresholds found in the Long Valley Caldera (Brodsky and Prejean, 2005), the Parkfield section of San Andreas Fault (Peng et al., 2009), and near the San Jacinto Fault (Kane et al., 2007). The triggered events occur almost instantaneously with the arrival of large amplitude seismic waves and appear to be modulated by the passing surface waves, similar to recent observations of triggered deep “non-volcanic” tremor along major plate boundary faults in California, Cascadia, Japan, and Taiwan (Peng and Gomberg, 2010). However, unlike these deep ‘tremor’ events, the triggered signals we find in this study have very short P- to S-arrival times, suggesting that they likely originate from brittle failure in the shallow crust. Confirming this, spectra of the triggered signals mimic spectra of typical shallow events in the region. Extending our observation time window to ~1 month following the mainshock event we find that for the 2010 Mw 7.2 Northern Baja California mainshock

  5. Sea level variability influencing coastal flooding in the Swan River region, Western Australia

    NASA Astrophysics Data System (ADS)

    Eliot, Matt

    2012-02-01

    Coastal flooding refers to the incidence of high water levels produced by water level fluctuations of marine origin, rather than riverine floods. An understanding of the amplitude and frequency of high water level events is essential to foreshore management and the design of many coastal and estuarine facilities. Coastal flooding events generally determine public perception of sea level phenomena, as they are commonly associated with erosion events. This investigation has explored the nature of coastal flooding events affecting the Swan River Region, Western Australia, considering water level records at four sites in the estuary and lower river, extending from the mouth of the Swan River to 40 km upstream. The analysis examined the significance of tides, storms and mean sea level fluctuations over both seasonal and inter-annual time scales. The relative timing of these processes is significant for the enhanced or reduced frequency of coastal flooding. These variations overlie net sea level rise previously reported from the coastal Fremantle record, which is further supported by changes to the distribution of high water level events at an estuarine tidal station. Seasonally, coastal flooding events observed in the Swan River region are largely restricted to the period from May to July due to the relative phases of the annual mean sea fluctuation and biannual tidal cycle. Although significant storm surge events occur outside this period, their impact is normally reduced, as they are superimposed on lower tidal and mean sea level conditions. Over inter-annual time scales tide, storminess and mean sea level produce cycles of enhanced and depressed frequency of coastal flooding. For the Swan River region, the inter-annual tidal variation is regular, dominated by the 18.6 year lunar nodal cycle. Storminess and mean sea level variations are independent and irregular, with cycles from 3 to 10 year duration. Since 1960, these fluctuations have not occurred in phase

  6. The Solomon Sea eddy activity from a 1/36° regional model

    NASA Astrophysics Data System (ADS)

    Djath, Bughsin; Babonneix, Antoine; Gourdeau, Lionel; Marin, Frédéric; Verron, Jacques

    2013-04-01

    In the South West Pacific, the Solomon Sea exhibits the highest levels of eddy kinetic energy but relatively little is known about the eddy activity in this region. This Sea is directly influenced by a monsoonal regime and ENSO variability, and occupies a strategical location as the Western Boundary Currents exiting it are known to feed the warm pool and to be the principal sources of the Equatorial UnderCurrent. During their transit in the Solomon Sea, meso-scale eddies are suspected to notably interact and influence these water masses. The goal of this study is to give an exhaustive description of this eddy activity. A dual approach, based both on altimetric data and high resolution modeling, has then been chosen for this purpose. First, an algorithm is applied on nearly 20 years of 1/3° x 1/3° gridded SLA maps (provided by the AVISO project). This allows eddies to be automatically detected and tracked, thus providing some basic eddy properties. The preliminary results show that two main and distinct types of eddies are detected. Eddies in the north-eastern part shows a variability associated with the mean structure, while those in the southern part are associated with generation/propagation processes. However, the resolution of the AVISO dataset is not very well suited to observe fine structures and to match with the numerous islands bordering the Solomon Sea. For this reason, we will confront these observations with the outputs of a 1/36° resolution realistic model of the Solomon Sea. The high resolution numerical model (1/36°) indeed permits to reproduce very fine scale features, such as eddies and filaments. The model is two-way embedded in a 1/12° regional model which is itself one-way embedded in the DRAKKAR 1/12° global model. The NEMO code is used as well as the AGRIF software for model nestings. Validation is realized by comparison with AVISO observations and available in situ data. In preparing the future wide-swath altimetric SWOT mission that is

  7. Simulating multi-decadal variability of Caspian Sea level changes using regional climate model outputs

    NASA Astrophysics Data System (ADS)

    Elguindi, N.; Giorgi, F.

    2006-02-01

    The Caspian Sea is the largest enclosed body of water on earth, covering approximately 4×105 km2 and sharing its coast with five countries (Iran, Azerbaijan, Kazakhstan, Russia and Turkmenistan). Because it has no outlet to the ocean the Caspian Sea level (CSL) has undergone rapid shifts in response to climatic forcings, and these have been devastating for the surrounding countries. In this paper we present the initial results of a modeling effort aimed at building a regional climate model for the Caspian Sea basin suitable to study the response of the CSL to interdecadal climate variability and anthropogenic climate change. Simulations are performed using the International Centre for Theoretical Physics (ICTP) regional climate model RegCM at a 50 km grid spacing for the period 1948 1990. During this period an abrupt shift occurred in the sea level after 1977, when the CSL rose about two meters until the early 1990s. Using a simple equation of hydrologic balance for the Caspian Sea basin to predict the CSL, we show that the model is able to reproduce the observed CSL changes at interannual to multidecadal scales. The correlation coefficient between the simulated and observed annual CSL changes is 0.91 and the model is able to reproduce the abrupt shift in CSL which occurred after 1977. Analysis of the climatologies before and after 1977 indicate that the CSL rise was mostly due to an increase in precipitation over the northern basin and a decrease in evaporation over the sea, primarily during the warm season. We plan to apply our model to the investigation of the response of the CSL to anthropogenic climate forcings.

  8. Simulating the water balance of the Aral Sea with a coupled regional climate-lake model

    USGS Publications Warehouse

    Small, E.E.; Sloan, L.C.; Hostetler, S.; Giorgi, F.

    1999-01-01

    Before coupled atmosphere-lake models can be used to study the response of large lake systems to climatic forcings, we must first evaluate how well they simulate the water balance and associated lake atmosphere interactions under present-day conditions. We evaluate the hydrology simulated by a lake model coupled to NCAR's regional climate model (RegCM2) in a study of the Aral Sea. The meteorological variables that are input to the lake model are simulated well by RegCM2. Simulated surface air temperatures closely match observed values, except during spring and fall when the simulated temperatures are too cold. The magnitude of precipitation is too high in the region surrounding the Aral Sea during summer and fall. On a yearly basis, RegCM2 produces a reasonable amount of runoff throughout the drainage basin. The lake model coupled to RegCM2 accurately simulates Aral Sea surface temperatures (SSTs). The lake model also simulates observed mid-winter ice fraction well, although the onset of ice growth occurs too late in the year and the ice melts too rapidly in the spring. The simulated annual evaporation from the Aral Sea is consistent with observed estimates; however, the simulated evaporation is greater than observed during summer and less than observed during winter. In a "stand-alone" lake model simulation, the simulated Aral Sea hydrology does not match observations as closely as in the coupled model experiment. These results suggest that a stand-alone lake model would not accurately simulate the hydrologic response of the Aral Sea to various forcings. Copyright 1999 by the American Geophysical Union.

  9. Emerging Persistent Organic Pollutants in Chinese Bohai Sea and Its Coastal Regions

    PubMed Central

    Wang, Yawei; Pan, Yuanyuan

    2014-01-01

    Emerging persistent organic pollutants (POPs) have widely aroused public concern in recent years. Polybrominated diphenyl ethers (PBDEs) and perfluorooctane sulfonyl fluoride/perfluorooctane sulfonic acid (POSF/PFOS) had been newly listed in Stockholm Convention in 2009, and short chain chlorinated paraffins (SCCPs) and hexabromocyclododecanes (HBCDs) were listed as candidate POPs. Bohai Sea is located in the arms of numbers of industrial cities, the semienclosed location of which makes it an ideal sink of emerging pollutants. In the present paper, latest contamination status of emerging POPs in Bohai Sea was reviewed. According to the literature data, Bohai Sea areas are not heavily contaminated by emerging POPs (PBDE: 0.01–720 ng/g; perfluorinated compounds: 0.1–304 ng/g; SCCPs: 64.9–5510 ng/g; HBCDs: nd-634 ng/g). Therefore, humans are not likely to be under serious risk of emerging POPs exposure through consuming seafood from Bohai Sea. However, the ubiquitous occurrence of emerging POPs in Bohai Sea region might indicate that more work should be done to expand the knowledge about potential risk of emerging POPs pollution. PMID:24688410

  10. Potential sea salt aerosol sources from frost flowers in the pan-Arctic region

    SciTech Connect

    Xu, Li; Russell, Lynn M.; Burrows, Susannah M.

    2016-09-23

    In order to better represent observed wintertime aerosol concentrations at Barrow, Alaska, we implemented an observationally-based parameterization for estimating sea salt production from frost flowers in the Community Earth System Model (CESM). In this work, we evaluate the potential influence of this sea salt source on the pan-Arctic (60ºN-90ºN) climate. Results show that frost flower salt emissions substantially increase the modeled surface sea salt aerosol concentration in the winter months when new sea ice and frost flowers are present. The parameterization reproduces both the magnitude and seasonal variation of the observed submicron sea salt aerosol concentration at surface in Barrow during winter much better than the standard CESM simulation without a frost-flower salt particle source. Adding these frost flower salt particle emissions increases aerosol optical depth by 10% and results in a small cooling at surface. The increase in salt particle mass concentrations of a factor of 8 provides nearly two times the cloud condensation nuclei concentration, as well as 10% increases in cloud droplet number and 40% increases in liquid water content near coastal regions adjacent to continents. These cloud changes reduce longwave cloud forcing by 3% and cause a small surface warming, increasing the downward longwave flux at the surface by 2 W m-2 in the pan-Arctic under the present-day climate.

  11. Geometry, thermal structure and kinematics of the metamorphic dome of Ikaria (eastern Cyclades, Greece): implication for Aegean tectonics

    NASA Astrophysics Data System (ADS)

    Beaudoin, Alexandre; Laurent, Valentin; Augier, Romain; Jolivet, Laurent; Lahfid, Abdeltif; Arbaret, Laurent; Rabillard, Aurélien

    2014-05-01

    The Aegean domain has been characterized since the Oligocene by extensional tectonics caused by the southward retreat of the African slab subducting beneath Eurasia. Structures and associated kinematics relative to this extensional tectonics are well constrained in the western Cyclades and the Menderes massif of western Turkey. Major extensional detachments such as the North Cycladic Detachment System (NCDS) or the Simav Detachment have accommodated the exhumation of a series of metamorphic core complexes (MCC) from Andros-Tinos-Mykonos in the west to the northern Menderes massif in the east. However, the transition between the NCDS and the Simav Detachment is currently not understood. This transition is located above a large-scale tear in the Aegean slab and its effects on the kinematics of deformation and P-T-t evolution of the overlying thinned crust are not known. The geology of Ikaria Island, located in this region, remains poorly known and the few existing studies are strikingly conflicting. This work attempts to clarify the geology of Ikaria by a new geological mapping and structural field study coupled with a thermometric study by Raman spectrometry of carbonaceous material (RSCM). Foliation over the whole island defines a structural dome, lately intruded by intrusive granitic bodies. Lineation shows a ca. N-S ductile stretching associated with an overall top-to-the-North sense of shear. Final exhumation of the dome was thus completed by a system of two top-to-the-North detachments, operating in the ductile and then the brittle fields. The proposed tectono-metamorphic evolution of the dome is consistent with the evolution of the northern Aegean area, suggesting that Ikaria belongs to the Aegean MCC and that the NCDS continues eastward. Besides, the distribution of RSCM temperatures within the dome and the presence of migmatites in the western part of the island comply with the description of migmatite-cored MCC such as Naxos or Mykonos. A better

  12. Peeking through the trapdoor: Historical biogeography of the Aegean endemic spider Cyrtocarenum Ausserer, 1871 with an estimation of mtDNA substitution rates for Mygalomorphae.

    PubMed

    Kornilios, P; Thanou, E; Kapli, P; Parmakelis, A; Chatzaki, M

    2016-05-01

    The Aegean region, located in the Eastern Mediterranean, is an area of rich biodiversity and endemism. Its position, geographical configuration and complex geological history have shaped the diversification history of many animal taxa. Mygalomorph spiders have drawn the attention of researchers, as excellent model systems for phylogeographical investigations. However, phylogeographic studies of spiders in the Aegean region are scarce. In this study, we focused on the phylogeography of the endemic ctenizid trap-door spider Cyrtocarenum Ausserer, 1871. The genus includes two morphologically described species: C. grajum (C.L. Koch, 1836) and C. cunicularium (Olivier, 1811). We sampled 60 specimens from the distributions of both species and analyzed four mitochondrial and two nuclear markers. Cyrtocarenum served as an example to demonstrate the importance of natural history traits in the inference of phylogeographic scenarios. The mtDNA substitution rates inferred for the genus are profoundly higher compared to araneomorph spiders and other arthropods, which seems tightly associated with their biology. We evaluate published mtDNA substitution rates followed in the literature for mygalomorph spiders and discuss potential pitfalls. Following gene tree (maximum likelihood, Bayesian inference) and species tree approaches ((*)BEAST), we reconstructed a time-calibrated phylogeny of the genus. These results, combined with a biogeographical ancestral-area analysis, helped build a biogeographic scenario that describes how the major palaeogeographic and palaeoclimatic events of the Aegean may have affected the distribution of Cyrtocarenum lineages. The diversification of the genus seems to have begun in the Middle Miocene in the present west Aegean area, while major phylogenetic events occurred at the Miocene-Pliocene boundary for C. cunicularium, probably related to the Messinian Salinity Crisis. Our results also demonstrate the clear molecular distinction of the two

  13. Estimating shipping emissions in the region of the Sea of Marmara, Turkey.

    PubMed

    Deniz, Cengiz; Durmuşoğlu, Yalçin

    2008-02-01

    Ship emissions are significantly increasing globally and have remarkable impact on air quality on sea and land. These emissions contribute serious adverse health and environmental effects. Territorial waters, inland seas and ports are the regions most affected by ship emissions. As an inland sea the Sea of Marmara is an area that has too much ship traffic. Since the region of the Marmara is highly urbanized, emissions from ships affect human health and the overall environment. In this paper exhaust gas emissions from ships in the Sea of Marmara and the Turkish Straits are calculated by utilizing the data acquired in 2003. Main engine types, fuel types, operations types, navigation times and speeds of vessels are taken into consideration in the study. Total emissions from ships in the study area were estimated as 5,451,224 t y(-1) for CO(2), 111,039 t y(-1) for NO(x), 87,168 t y(-1) for SO(2), 20,281 t y(-1) for CO, 5801 t y(-1) for VOC, 4762 t y(-1) for PM. The shipping emissions in the region are equivalent to 11% of NO(x) 0.1% of CO and 0.12% of PM of the corresponding total emissions in Turkey. The shipping emissions in the area are 46% of NO(x), 25% of PM and 1.5% of CO of road traffic emissions in Turkey data between which and correspond to a higher level than aircraft emissions and rail emissions in Turkey.

  14. Large-Scale Covariability Between Aerosol and Precipitation Over the 7-SEAS Region: Observations and Simulations

    NASA Technical Reports Server (NTRS)

    Huang, Jingfeng; Hsu, N. Christina; Tsay, Si-Chee; Zhang, Chidong; Jeong, Myeong Jae; Gautam, Ritesh; Bettenhausen, Corey; Sayer, Andrew M.; Hansell, Richard A.; Liu, Xiaohong; Jiang, Jonathan H.

    2012-01-01

    One of the seven scientific areas of interests of the 7-SEAS field campaign is to evaluate the impact of aerosol on cloud and precipitation (http://7-seas.gsfc.nasa.gov). However, large-scale covariability between aerosol, cloud and precipitation is complicated not only by ambient environment and a variety of aerosol effects, but also by effects from rain washout and climate factors. This study characterizes large-scale aerosol-cloud-precipitation covariability through synergy of long-term multi ]sensor satellite observations with model simulations over the 7-SEAS region [10S-30N, 95E-130E]. Results show that climate factors such as ENSO significantly modulate aerosol and precipitation over the region simultaneously. After removal of climate factor effects, aerosol and precipitation are significantly anti-correlated over the southern part of the region, where high aerosols loading is associated with overall reduced total precipitation with intensified rain rates and decreased rain frequency, decreased tropospheric latent heating, suppressed cloud top height and increased outgoing longwave radiation, enhanced clear-sky shortwave TOA flux but reduced all-sky shortwave TOA flux in deep convective regimes; but such covariability becomes less notable over the northern counterpart of the region where low ]level stratus are found. Using CO as a proxy of biomass burning aerosols to minimize the washout effect, large-scale covariability between CO and precipitation was also investigated and similar large-scale covariability observed. Model simulations with NCAR CAM5 were found to show similar effects to observations in the spatio-temporal patterns. Results from both observations and simulations are valuable for improving our understanding of this region's meteorological system and the roles of aerosol within it. Key words: aerosol; precipitation; large-scale covariability; aerosol effects; washout; climate factors; 7- SEAS; CO; CAM5

  15. Modeling the Response of the Mediterranean Sea Level to Global and Regional Climatic Phenomena

    NASA Astrophysics Data System (ADS)

    Natsiopoulos, D. A.; Vergos, G. S.; Tziavos, I. N.

    2016-08-01

    The exploitation of satellite altimetry data from past and current satellite missions is crucial to both oceanographic and geodetic applications. This work presents a correlation analysis of Jason-1, Jason-2 and CryoSat-2 Sea Level Anomalies (SLAs) with global and regional climatic indexes that influence the ocean state. The Southern Oscillation Index, North Atlantic Oscillation index and Mediterranean Oscillation Index have been investigated, as representative of climate-change and seasonal forcing on the sea level. The raw data used are SLA values from Jason-1, Jason-2 (2002-2014) and CryoSat-2 (2010-2014) over the entire Mediterranean Basin. The possible correlation is investigated in seasonal and monthly scale, while a regional multiple regression and a principal component analysis between the SLAs and oscillation indexes is carried out. Finally, evidence of the sea level cyclo-stationarity in the Mediterranean Sea is deduced from the analysis of empirically derived covariance functions at monthly intervals from the available SLA data.

  16. Potential sea salt aerosol sources from frost flowers in the pan-Arctic region

    NASA Astrophysics Data System (ADS)

    Xu, Li; Russell, Lynn M.; Burrows, Susannah M.

    2016-09-01

    In order to better represent observed wintertime aerosol mass and number concentrations in the pan-Arctic (60°N-90°N) region, we implemented an observationally based parameterization for estimating sea salt production from frost flowers in the Community Earth System Model (CESM, version 1.2.1). In this work, we evaluate the potential influence of this sea salt source on the pan-Arctic climate. Results show that frost flower salt emissions increase the modeled surface sea salt aerosol mass concentration by roughly 200% at Barrow and 100% at Alert and accumulation-mode number concentration by about a factor of 2 at Barrow and more than a factor of 10 at Alert in the winter months when new sea ice and frost flowers are present. The magnitude of sea salt aerosol mass and number concentrations at the surface in Barrow during winter simulated by the model configuration that includes this parameterization agrees better with observations by 48% and 12%, respectively, than the standard CESM simulation without a frost flower salt particle source. At Alert, the simulation with this parameterization overestimates observed sea salt aerosol mass concentration by 150% during winter in contrast to the underestimation of 63% in the simulation without this frost flower source, while it produces particle number concentration about 14% closer to observation than the standard CESM simulation. However, because the CESM version used here underestimates transported sulfate in winter, the reference accumulation-mode number concentrations at Alert are also underestimated. Adding these frost flower salt particle emissions increases sea salt aerosol optical depth by 10% in the pan-Arctic region and results in a small cooling at the surface. The increase in salt aerosol mass concentrations of a factor of 8 provides nearly two times the cloud condensation nuclei concentration at supersaturation of 0.1%, as well as 10% increases in cloud droplet number and 40% increases in liquid water content

  17. An integrated approach to teaching Aegean archaeology and archaeological science

    NASA Astrophysics Data System (ADS)

    Pitcairn, Erica Glenn

    Outlined here is a course that would serve as an introduction to archaeological science, specifically within the context of Aegean Prehistory. The main objective of this course is to expose students early in their archaeological careers to a variety of methods and questions, and to depart from the culture-historical perspective that typifies introductory survey courses. The class structure is equal parts lecture and discussion, moving between learning how the methods work and evaluating case studies. All graded assignments build on one another, guiding the students through designing their own research project. The ultimate goals of the assignments are to build key writing and professional skills, develop a basic understanding of research design, and to instill confidence that the student can contribute to the production of knowledge, whatever field he or she decides to pursue.

  18. Fog water collection under sea breeze conditions in the Western Mediterranean basin (Valencia region, Spain)

    NASA Astrophysics Data System (ADS)

    Azorin-Molina, C.; Corell, D.; Estrela, M. J.; Valiente, J. A.

    2010-07-01

    Orographic fog occurrences associated with sea breezes determine water collection potential over the mountain ranges near the Mediterranean coast of the Iberian Peninsula. Previous works have confirmed that the effect of sea breezes on cloud genera is to increase the frequency of low (Stratus) and convective (Cumulus) clouds. The primary impact of sea breeze flows corresponds to low stratiform clouds (Stratus, St, and Stratocumulus, Sc) formed in the convective internal boundary layer due to the inflow of moist sea air at lower levels. The formation of Sc clouds is caused by the rising and cooling of turbulent moist sea air over the highest slopes of the mountains at the end of the day. In the most Sc formation, we also observed dense fog banks of Stratus nebulosus (St neb) and dew during the early next morning, covering the inland topographical depressions. The aim of this study is to statistically analyze the impact of sea breezes on fog water collection in the convective internal boundary layer. The study area is located in the eastern of the Iberian Peninsula (Valencia region, Spain) and the survey corresponds to a 7-yr study period (2003-2009). This research is based upon a small network of eight passive fog water collectors distributed over 6 coastal- and 2 inland-mountain areas. A cylindrical fog water instrument (i.e. omnidirectional collection efficiency) based on the ASRC (Atmospheric Science Research Centre, State University of New York) string collector is used to sample fog water volumes on a daily basis. These stations also sampled temperature, humidity, wind speed and direction and precipitation measurements. The current study used these meteorological measurements to apply an automated and manual selection methodologies for identifying past sea breeze episodes. The dataset created by means of these selection techniques allows for the study of fog water volumes associated with sea breeze situations. A detailed statistical characterization of the

  19. The contribution of ship emissions to air pollution in the North Sea regions.

    PubMed

    Matthias, Volker; Bewersdorff, Ines; Aulinger, Armin; Quante, Markus

    2010-06-01

    As a consequence of the global distribution of manufacturing sites and the increasing international division of labour, ship traffic is steadily increasing and is becoming more and more important as an origin of air pollution. This study investigates the impact of ship emissions in coastal areas of the North Sea under conditions of the year 2000 by means of a regional chemistry transport model which runs on a sufficiently high resolution to study air pollution in coastal regions. It was found that northern Germany and Denmark in summer suffer from more than 50% higher sulphate, nitrate and ammonium aerosol concentrations due to contributions from ships. The implementation of a sulphur emission control area (SECA) in the North Sea, as it was implemented at the end of 2007, directly results in reduced sulphur dioxide and sulphate aerosol concentrations while nitrate aerosol concentrations are slightly increased.

  20. Influence of regional tectonics on halokinesis in the Nordkapp Basin, Barents Sea

    SciTech Connect

    Nilsen, K.T.; Johansen, J.T.; Vendeville, B.C.

    1996-12-31

    Seismic analysis of salt structures in the Nordkapp Basin, a deep salt basin in the southern Barents Sea, combined with experimental modeling suggests that regional tectonics closely controlled diapiric growth. Diapirs formed in the Early Triassic during basement-involved regional extension. The diapirs then rose rapidly by passive growth and exhausted their source layer. Regional extension in the Middle-Late Triassic triggered down-to-the-basin gravity gliding, which laterally shortened the diapirs. This squeezed salt out of diapir stems, forcing diapirs to rise, extrude, and form diapir overhangs. After burial under more than 1000 m of Upper Triassic-Lower Cretaceous sediments, the diapirs were rejuvenated by a Late Cretaceous episode of regional extension and gravity gliding, which deformed their thick roofs. After extension, diapirs stopped rising and were buried under 1500 m of lower Tertiary sediments. Regional compression of the Barents Sea region in the middle Tertiary caused one more episode of diapiric rise. Diapirs in the Nordkapp Basin are now extinct.

  1. Non-linear feedbacks affecting sea ice deformation in the Regional Arctic System Model (RASM)

    NASA Astrophysics Data System (ADS)

    Roberts, A.; Maslowski, W.; Mills, T.; Hunke, E. C.; Craig, A.; Osinski, R.; Cassano, J. J.; Duvivier, A.; Hughes, M.; Zeng, X.; Brunke, M.; Gutowski, W. J., Jr.; Fisel, B. J.

    2014-12-01

    We present the latest results of high-resolution sea ice simulations from the fully coupled Regional Arctic System Model (RASM), including explicit melt ponds, form drag and anisotropic sea ice rheology. RASM is a pan-Arctic model composed of the Parallel Ocean Program (POP) and Los Alamos Sea ice Model (CICE5) at ~9km resolution, coupled to the Weather Research and Forecasting Model (WRF) and Variable Infiltration Capacity (VIC) model at 50km resolution using the Community Earth System Model (CESM) coupling framework. Using RASM, we have analyzed coupled feedbacks resulting from different sea ice mechanics formulations. Strong spatial and temporal scaling of sea ice deformation has been observed in the Arctic using the Radarsat Geophysical Processing System and Global Positioning System equipped buoys. Whereas previous results from stand-alone ice-ocean simulations suggest that the established Elastic Viscous Plastic (EVP) rheology is unable to replicate these features, RASM simulates the observed scaling using EVP, with a spatial scaling fractal dimension of around -0.23, as compared to the observed range of -0.18 to -0.20. Using this metric, we extend our analysis to test for spatial scaling in sea ice deformation using a recently revised EVP formulation, as well as the new Elastic Plastic Anistropic rheology in CICE5. Our results suggest that a fundamental source of scaling stems from feedbacks associated with frequent coupling between high resolution ocean and atmospheric models, and this result serves as an example of the broader utility of limited-area, fully coupled models in isolating coupled feedbacks and evaluating them using daily in-situ and satellite measurements.

  2. The Caspian Sea regionalism in a globalized world: Energy security and regional trajectories of Azerbaijan and Iran

    NASA Astrophysics Data System (ADS)

    Hedjazi, Babak

    2007-12-01

    This dissertation is fundamentally about the formation of new regional spaces in Central Eurasia viewed from a dynamic, comparative and historical approach. Analyzing the global-local economic and political interactions and their consequences on resource rich countries of the Caspian Sea enable us to reframe security as a central element of the new global order. In this respect, the dissertation examines how two particular states, Azerbaijan and Iran, respond to the changing global security environment and optimize their capacity to absorb or control change. Here, security as I conceive is multidimensional and engages various social, political and economic domains. My research is articulated along three hypotheses regarding the formation of a new regional space and its consequences on territorial polarization and interstate rivalry. These hypotheses, respectively and cumulatively, elucidate global and domestic contexts of regional space formation, regional strategic and discursive trajectories, and regional tensions of global/local interactions. In order to empirically test these hypotheses, a series of thirty interviews were conducted by the author with local and foreign business representatives, civilian and government representatives, and corroborated by economic data collected from the International Energy Agency. The findings of the research validate the primary assumption of the dissertation that Azerbaijan and Iran have chosen the regional scale to address discrepancies between their aspired place in the new world order and the reality of their power and international status. Extending the argument for structural scarcity of oil towards contenders, this dissertation concludes that the Caspian oil has become a fundamental element of the regional discourse. The mismatch between the rhetoric of sovereign rights and energy security on one side and the reality of regional countries' powerlessness and their need to reach international markets on the other side are

  3. Characterization of OMI tropospheric NO2 over the Baltic Sea region

    NASA Astrophysics Data System (ADS)

    Ialongo, I.; Hakkarainen, J.; Hyttinen, N.; Jalkanen, J.-P.; Johansson, L.; Boersma, K. F.; Krotkov, N.; Tamminen, J.

    2014-08-01

    Satellite-based data are very important for air-quality applications in the Baltic Sea region, because they provide information on air pollution over the sea and where ground-based and aircraft measurements are not available. Both the emissions from urban sites over land and ships over sea, contribute to tropospheric NO2 levels. Tropospheric NO2 monitoring at high latitudes using satellite data is challenging because of the reduced light hours in winter and the weak signal due to the low Sun, which make the retrieval complex. This work presents a characterization of tropospheric NO2 columns based on case-study analysis in the Baltic Sea region, using the Ozone Monitoring Instrument (OMI) tropospheric NO2 standard product. Previous works have focused on larger seas and lower latitudes. The results of this paper showed that, despite the regional area of interest, it is possible to distinguish the signal from the main coastal cities and from the ships by averaging the data over a~seasonal time range. The summertime NO2 emission and lifetime values (E' = (1.5 ± 0.6) mol s-1 and τ = (3 ± 1) h, respectively) in Helsinki were estimated from the decay of the signal with distance from the city center. These results agree within the uncertainties with the emissions from the existing database. For comparison, the results for the cities of Saint Petersburg and Stockholm are also shown. The method developed for megacities was successfully applied to smaller-scale sources, in both size and intensity, which are located at high latitudes (~60° N). The same methodology could be applied to similar-scale cities elsewhere, as long as they are relatively isolated from other sources. Transport by the wind plays an important role in the Baltic Sea region. The NO2 spatial distribution is mainly determined by the contribution of westerly winds, which dominate the wind patterns during summer. The comparison between the ship emissions from model calculations and OMI NO2 tropospheric

  4. Assessment of Precipitation Forecast Accuracy over Eastern Black Sea Region using WRF-ARW

    NASA Astrophysics Data System (ADS)

    Bıyık, G.; Unal, Y.; Onol, B.

    2009-09-01

    Surface topography such as mountain barriers, existing water bodies and semi-permanent mountain glaciers changes large scale atmospheric patterns and creates a challenge for a reliable precipitation prediction. Eastern Black sea region of Turkey is an example. Black Sea Mountain chains lies west to east along the coastline with the average height of 2000 m and the highest point is 3973 m, and from the coastline to inland there is a very sharp topography change. For this project we select the Eastern Black Sea region of Turkey to assess precipitation forecast accuracy. This is a unique region of Turkey which receive both highest amount of precipitation and precipitation throughout whole year. Amount of rain and snow is important because they supply water to the main river systems of Turkey. Turkey is in general under the influence of both continental polar (Cp) and tropical air masses. Their interaction with the orography causes orographic precipitation being effective on the region. Also Caucasus Mountains, which is the highest point of Georgia, moderates the climate of the southern parts by not letting penetration of colder air masses from north. Southern part of the western Black Sea region has more continental climate because of the lee side effect of the mountains Therefore, precipitation forecast in the region is important for operational forecasters and researchers. Our aim in this project is to investigate WRF precipitation accuracy during 10 extreme precipitation, 10 normal precipitation and 10 no precipitation days by using forecast for two days ahead. Cases are selected in years between 2000 and 2003. Eleven Eastern Black Sea stations located along the coastline are used to determine 20 extreme and 10 average precipitation days. During project, three different resolutions with three nested domains are tested to determine the model sensivity to domain boundaries and resolution. As a result of our tests, 6 km resolution for finer domain was found suitable

  5. Climatological aspects of mesoscale cyclogenesis over the Ross Sea and Ross Ice shelf regions of Antarctica

    SciTech Connect

    Carrasco, J.F.; Bromwich, D.H.

    1994-11-01

    A one-year (1988) statistical study of mesoscale cyclogenesis near Terra Nova Bay and Byrd Glacier, Antarctica, was conducted using high-resolution digital satellite imagery and automatic weather station data. Results indicate that on average two (one) mesoscale cyclones form near Terra Nova Bay (Byrd Glacier) each week, confirming these two locations as mesoscale cyclogeneis areas. The maximum (minimum) weekly frequency of mesoscale cyclones occurred during the summer (winter). The satellite survey of mesoscale vortices was extended over the Ross Sea and Ross Ice Shelf. Results suggest southern Marie Byrd Land as another area of mesoscale cyclone formation. Also, frequent mesoscale cyclonic activity was noted over the Ross Sea and Ross Ice Shelf, where, on average, six and three mesoscale vortices were observed each week, respectively, with maximum (minimum) frequency during summer (winter) in both regions. The majority (70-80%) of the vortices were of comma-cloud type and were shallow. Only around 10% of the vortices near Terra Nova Bay and Byrd Glacier were classified as deep vortices, while over the Ross Sea and Ross Ice Shelf around 20% were found to be deep. The average large-scale pattern associated with cyclogenesis days near Terra Nova Bay suggests a slight decrease in the sea level pressure and 500-hPa geopotential height to the northwest of this area with respect to the annual average. This may be an indication of the average position of synoptic-scale cyclones entering the Ross Sea region. Comparison with a similar study but for 1984-85 shows that the overall mesoscale cyclogenesis activity was similar during the three years, but 1985 was found to be the year with greater occurrence of {open_quotes}significant{close_quotes} mesoscales cyclones. The large-scale pattern indicates that this greater activity is related to a deeper circumpolar trough and 500-hPa polar vortex for 1985 in comparison to 1984 and 1988. 64 refs., 13 figs., 5 tabs.

  6. Prophage-Encoded Staphylococcal Enterotoxin A: Regulation of Production in Staphylococcus aureus Strains Representing Different Sea Regions.

    PubMed

    Zeaki, Nikoleta; Susilo, Yusak Budi; Pregiel, Anna; Rådström, Peter; Schelin, Jenny

    2015-12-09

    The present study investigates the nature of the link between the staphylococcal enterotoxin A (SEA) gene and the lifecycle of Siphoviridae bacteriophages, including the origin of strain variation regarding SEA production after prophage induction. Five strains representing three different genetic lines of the sea region were studied under optimal and prophage-induced growth conditions and the Siphoviridae lifecycle was followed through the phage replicative form copies and transcripts of the lysogenic repressor, cro. The role of SOS response on prophage induction was addressed through recA transcription in a recA-disruption mutant. Prophage induction was found to increase the abundance of the phage replicative form, the sea gene copies and transcripts and enhance SEA production. Sequence analysis of the sea regions revealed that observed strain variances were related to strain capacity for prophage induction, rather than sequence differences in the sea region. The impact of SOS response activation on the phage lifecycle was demonstrated by the absence of phage replicative form copies in the recA-disruption mutant after prophage induction. From this study it emerges that all aspects of SEA-producing strain, the Siphoviridae phage and the food environment must be considered when evaluating SEA-related hazards.

  7. Quantifying and Projecting Relative Sea-Level Rise At The Regional Scale: The Bangladesh Sea-Level Project (BanD-AID)

    NASA Astrophysics Data System (ADS)

    Shum, C. K.; Kuo, C. Y.; Guo, J.; Shang, K.; Tseng, K. H.; Wan, J.; Calmant, S.; Ballu, V.; Valty, P.; Kusche, J.; Hossain, F.; Khan, Z. H.; Rietbroek, R.; Uebbing, B.

    2014-12-01

    The potential for accelerated sea-level rise under anthropogenic warming is a significant societal problem, in particular in world's coastal deltaic regions where about half of the world's population resides. Quantifying geophysical sources of sea-level rise with the goal of improved projection at local scales remains a complex and challenging interdisciplinary research problem. These processes include ice-sheet/glacier ablations, steric sea-level, solid Earth uplift or subsidence due to GIA, tectonics, sediment loading or anthropogenic causes, hydrologic imbalance, and human processes including water retention in reservoirs and aquifer extraction. The 2013 IPCC AR5 concluded that the observed and explained geophysical causes of global geocentric sea-level rise, 1993-2010, is closer towards closure. However, the discrepancy reveals that circa 1.3→37.5% of the observed sea-level rise remains unexplained. This relatively large discrepancy is primarily attributable to the wide range of estimates of respective contributions of Greenland and Antarctic ice-sheets and mountain/peripheral glaciers to sea-level rise. Understanding and quantifying the natural and anthropogenic processes governing solid Earth (land, islands and sea-floor) uplift or subsidence at the regional and local scales remain elusive to enable addressing coastal vulnerability due to relative sea-level rise hazards, such as the Bangladesh Delta. This study focuses on addressing coastal vulnerability of Bangladesh, a Belmont Forum/IGFA project, BanD-AID (http://Belmont-SeaLevel.org). Sea-level rise, along with tectonic, sediment load and groundwater extraction induced land uplift/subsidence, have exacerbated Bangladesh's coastal vulnerability, affecting 150 million people in one of the world's most densely populated regions. Here we present preliminary results using space geodetic observations, including satellite radar and laser altimetry, GRACE gravity, tide gauge, hydrographic, and GPS/InSAR observed

  8. Characterization of Bacterial Communities in Deep-Sea Hydrothermal Vents from Three Oceanic Regions.

    PubMed

    He, Tianliang; Zhang, Xiaobo

    2016-04-01

    Deep-sea hydrothermal vents are considered to be one of the most spectacular ecosystems on Earth. Microorganisms form the basis of the food chain in vents controlling the vent communities. However, the diversity of bacterial communities in deep-sea hydrothermal vents from different oceans remains largely unknown. In this study, the pyrosequencing of 16S rRNA gene was used to characterize the bacterial communities of the venting sulfide, seawater, and tubeworm trophosome from East Pacific Rise, South Atlantic Ridge, and Southwest Indian Ridge, respectively. A total of 23,767 operational taxonomic units (OTUs) were assigned into 42 different phyla. Although Proteobacteria, Actinobacteria, and Bacteroidetes were the predominant phyla in all vents, differences of bacterial diversity were observed among different vents from three oceanic regions. The sulfides of East Pacific Rise possessed the most diverse bacterial communities. The bacterial diversities of venting seawater were much lower than those of vent sulfides. The symbiotic bacteria of tubeworm Ridgeia piscesae were included in the bacterial community of vent sulfides, suggesting their significant ecological functions as the primary producers in the deep-sea hydrothermal vent ecosystems. Therefore, our study presented a comprehensive view of bacterial communities in deep-sea hydrothermal vents from different oceans.

  9. Potential Inundation due to Rising Sea Levels in the San Francisco Bay Region

    USGS Publications Warehouse

    Knowles, Noah

    2009-01-01

    An increase in the rate of sea level rise is one of the primary impacts of projected global climate change. To assess potential inundation associated with a continued acceleration of sea level rise, the highest resolution elevation data available were assembled from various sources and mosaicked to cover the land surfaces of the San Francisco Bay region. Next, to quantify high water levels throughout the bay, a hydrodynamic model of the San Francisco Estuary was driven by a projection of hourly water levels at the Presidio. This projection was based on a combination of climate model outputs and empirical models and incorporates astronomical, storm surge, El Niño, and long-term sea level rise influences. Based on the resulting data, maps of areas vulnerable to inundation were produced, corresponding to specific amounts of sea level rise and recurrence intervals. These maps portray areas where inundation will likely be an increasing concern. In the North Bay, wetland survival and developed fill areas are at risk. In Central and South bays, a key feature is the bay-ward periphery of developed areas that would be newly vulnerable to inundation. Nearly all municipalities adjacent to South Bay face this risk to some degree. For the Bay as a whole, as early as 2050 under this scenario, the one-year peak event nearly equals the 100-year peak event in 2000. Maps of vulnerable areas are presented and some implications discussed.

  10. The Antarctic region as a marine biodiversity hotspot for echinoderms: Diversity and diversification of sea cucumbers

    NASA Astrophysics Data System (ADS)

    Mark O'Loughlin, P.; Paulay, Gustav; Davey, Niki; Michonneau, François

    2011-03-01

    The Antarctic region is renowned for its isolated, unusual, diverse, and disharmonic marine fauna. Holothuroids are especially diverse, with 187 species (including 51 that are undescribed) recorded south of the Antarctic Convergence. This represents ˜4% of the documented Antarctic marine biota, and ˜10% of the world's holothuroid diversity. We present evidence that both inter-regional speciation with southern cold-temperate regions and intra-regional diversification has contributed to species richness. The Antarctic fauna is isolated, with few shallow-water Antarctic species known from north of the Convergence, yet several species show recent transgression of this boundary followed by genetic divergence. Interchange at longer time scales is evidenced by the scarcity of endemic genera (10 of 55) and occurrence of all six holothuroid orders within the region. While most Antarctic holothuroid morphospecies have circum-polar distributions, mtDNA sequence data demonstrate substantial geographic differentiation in many of these. Thus, most of the 37 holothuroid species recorded from shelf/slope depths in the Weddell Sea have also been found in collections from Prydz Bay and the Ross Sea. Yet 17 of 28 morphospecies and complexes studied show allopatric differentiation around the continent, on average into three divergent lineages each, suggesting that morphological data fails to reflect the level of differentiation. Interchange and local radiation of colonizers appear to have rapidly built diversity in the Antarctic, despite the potential of cold temperatures (and associated long generation times) to slow the rate of evolution.

  11. Earthquake swarms reveal submarine magma unrest induced by distant mega-earthquakes: Andaman Sea region

    NASA Astrophysics Data System (ADS)

    Špičák, Aleš; Vaněk, Jiří

    2016-02-01

    Little is known about earthquake-triggered magma intrusions or eruptions of submarine volcanoes. The analysis of teleseismic earthquake occurrence performed in this study offers a tool to address such enigmatic and inaccessible processes. In the past ten years, the Andaman Sea region repeatedly became a site of shallow earthquake swarms that followed distant mega-earthquakes by days to weeks. The MW 9.1 December 26, 2004 Sumatra-Andaman earthquake was followed by two earthquake swarms about 600 km northward in the Andaman Sea region, delayed by 30 and 35 days, respectively. Earthquakes of one of these seismic episodes, the extensive January 2005 earthquake swarm, migrated laterally at a rate of about 0.25 km per hour during the swarm evolution. The strong Indian Ocean MW 8.6 and 8.2 April 11, 2012 earthquake doublet west of Northern Sumatra was followed by an earthquake swarm approximately 800 km northward in the Andaman Sea region, delayed by 13 days. All the three swarms that followed the 2004 and 2012 mega-earthquakes occurred beneath distinct seamounts and seafloor ridges. Based on the observations of migration of earthquakes during the swarm and swarm occurrence beneath distinct highs at the seafloor, we conclude that these earthquake swarms probably resulted as a consequence of magma unrest induced by static and/or dynamic stress changes following the distant mega-earthquakes. Repeated occurrence of such a phenomenon suggests that the arc magma reservoirs beneath the Andaman Sea have recently reached some form of criticality and are vulnerable to even small stress changes. The Andaman seafloor could thus become a site of submarine volcanic eruptions in near future and deserves close attention of Earth scientists.

  12. The character and significance of basement rocks of the southern Molucca Sea region

    NASA Astrophysics Data System (ADS)

    Hall, Robert; Nichols, Gary; Ballantyne, Paul; Charlton, Tim; Ali, Jason

    Pre-Neogene basement rocks in the southern Molucca Sea region include ophiolitic rocks, arc volcanic rocks and continental rocks. The ophiolitic complexes are associated with arc and forearc igneous and sedimentary rocks. They are interpreted as the oldest parts of the Philippine Sea Plate with equivalents in the ridges and plateaux of the northern Philippine Sea. In the Molucca Sea region igneous components include rocks with a "supra-subduction zone" character, bonintic volcanic rocks and basic volcanic rocks with a "within-plate" character; "MORB-type" rocks are rare or absent. The ophiolitic rocks are overlain by Upper Cretaceous and Eocene sedimentary and volcanic rocks. Plutonic rocks of island arc origin which intrude the ophiolites yield Late Cretaceous radiometric ages and amphibolites with ophiolitic protoliths yield Eocene ages. The "supra-subduction zone" ophiolites are speculated to have originated during a mid-Cretaceous plate reorganization event. For the Late Cretaceous and Eocene the present-day Marianas arc and forearc provides an attractive model. Volcanic rocks from the basement of Morotai, western Halmahera and much of Bacan. These also have an island arc character and are probably of Late Cretaceous-Paleogene age. Both the arc volcanic rocks and the ophiolitic complexes are overlain by shallow water Eocene limestones and an Oligocene rift sequence including basaltic pillow lavas and volcaniclastic turbidites. The distribution of the Eocene-Oligocene sequences indicate pre-Mid/Late Eocene amalgamation of the ophiolitic and arc terranes. Mid Eocene-Oligocene extension appears to be synchronous with opening of the central West Philippine Basin. Continental crust probably arrived in this region in the Late Paleogene-Early Neogene, either due to collision of the Australian margin with Pacific arc-ophiolite terranes or by terrane movement along the Sorong Fault Zone.

  13. 78 FR 60892 - Outer Continental Shelf (OCS), Alaska OCS Region, Chukchi Sea Planning Area, Proposed Oil and Gas...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-02

    ... Bureau of Ocean Energy Management Outer Continental Shelf (OCS), Alaska OCS Region, Chukchi Sea Planning Area, Proposed Oil and Gas Lease Sale 237 (Lease Sale 237) MMAA104000 AGENCY: Bureau of Ocean Energy... addressed in this Call (``Program Area'') is located offshore Alaska in the Chukchi Sea Planning Area....

  14. Quantitative reconstruction of Holocene sea ice and sea surface temperature off West Greenland from the first regional diatom data set

    NASA Astrophysics Data System (ADS)

    Krawczyk, D. W.; Witkowski, A.; Moros, M.; Lloyd, J. M.; Høyer, J. L.; Miettinen, A.; Kuijpers, A.

    2017-01-01

    Holocene oceanographic conditions in Disko Bay, West Greenland, were reconstructed from high-resolution diatom records derived from two marine sediment cores. A modern data set composed of 35 dated surface sediment samples collected along the West Greenland coast accompanied by remote sensing data was used to develop a diatom transfer function to reconstruct April sea ice concentration (SIC) supported by July sea surface temperature (SST) in the area. Our quantitative reconstruction shows that oceanographic changes recorded throughout the last 11,000 years reflect seasonal interplay between spring (April SIC) and summer (July SST) conditions. Our records show clear correlation with climate patterns identified from ice core data from GISP2 and Agassiz-Renland for the early to middle Holocene. The early Holocene deglaciation of western Greenland Ice Sheet was characterized in Disko Bay by initial strong centennial-scale fluctuations in April SIC with amplitude of over 40%, followed by high April SIC and July SST. These conditions correspond to a general warming of the climate in the Northern Hemisphere. A decrease in April SIC and July SST was recorded during the Holocene Thermal Optimum reflecting more stable spring-summer conditions in Disko Bay. During the late Holocene, high April SIC characterized the Medieval Climate Anomaly, while high July SST prevailed during the Little Ice Age, supporting previously identified antiphase relationship between surface waters in West Greenland and climate in NW Europe. This antiphase pattern might reflect seasonal variations in regional oceanographic conditions and large-scale fluctuations within the North Atlantic Oscillation and Atlantic Meridional Overturning Circulation.

  15. A Review of Recent Updates of Sea-Level Projections at Global and Regional Scales

    NASA Technical Reports Server (NTRS)

    Slangen, A. B. A.; Adloff, F.; Jevrejeva, S.; Leclercq, P. W.; Marzeion, B.; Wada, Yoshihide; Winkelmann, R.

    2016-01-01

    Sea-level change (SLC) is a much-studied topic in the area of climate research, integrating a range of climate science disciplines, and is expected to impact coastal communities around the world. As a result, this field is rapidly moving, and the knowledge and understanding of processes contributing to SLC is increasing. Here, we discuss noteworthy recent developments in the projection of SLC contributions and in the global mean and regional sea-level projections. For the Greenland Ice Sheet contribution to SLC, earlier estimates have been confirmed in recent research, but part of the source of this contribution has shifted from dynamics to surface melting. New insights into dynamic discharge processes and the onset of marine ice sheet instability increase the projected range for the Antarctic contribution by the end of the century. The contribution from both ice sheets is projected to increase further in the coming centuries to millennia. Recent updates of the global glacier outline database and new global glacier models have led to slightly lower projections for the glacier contribution to SLC (7-17 cm by 2100), but still project the glaciers to be an important contribution. For global mean sea-level projections, the focus has shifted to better estimating the uncertainty distributions of the projection time series, which may not necessarily follow a normal distribution. Instead, recent studies use skewed distributions with longer tails to higher uncertainties. Regional projections have been used to study regional uncertainty distributions, and regional projections are increasingly being applied to specific regions, countries, and coastal areas.

  16. A Review of Recent Updates of Sea-Level Projections at Global and Regional Scales

    NASA Astrophysics Data System (ADS)

    Slangen, A. B. A.; Adloff, F.; Jevrejeva, S.; Leclercq, P. W.; Marzeion, B.; Wada, Y.; Winkelmann, R.

    2017-01-01

    Sea-level change (SLC) is a much-studied topic in the area of climate research, integrating a range of climate science disciplines, and is expected to impact coastal communities around the world. As a result, this field is rapidly moving, and the knowledge and understanding of processes contributing to SLC is increasing. Here, we discuss noteworthy recent developments in the projection of SLC contributions and in the global mean and regional sea-level projections. For the Greenland Ice Sheet contribution to SLC, earlier estimates have been confirmed in recent research, but part of the source of this contribution has shifted from dynamics to surface melting. New insights into dynamic discharge processes and the onset of marine ice sheet instability increase the projected range for the Antarctic contribution by the end of the century. The contribution from both ice sheets is projected to increase further in the coming centuries to millennia. Recent updates of the global glacier outline database and new global glacier models have led to slightly lower projections for the glacier contribution to SLC (7-17 cm by 2100), but still project the glaciers to be an important contribution. For global mean sea-level projections, the focus has shifted to better estimating the uncertainty distributions of the projection time series, which may not necessarily follow a normal distribution. Instead, recent studies use skewed distributions with longer tails to higher uncertainties. Regional projections have been used to study regional uncertainty distributions, and regional projections are increasingly being applied to specific regions, countries, and coastal areas.

  17. A Connectivity-Based Eco-Regionalization Method of the Mediterranean Sea

    PubMed Central

    Berline, Léo; Rammou, Anna-Maria; Doglioli, Andrea; Molcard, Anne; Petrenko, Anne

    2014-01-01

    Ecoregionalization of the ocean is a necessary step for spatial management of marine resources. Previous ecoregionalization efforts were based either on the distribution of species or on the distribution of physical and biogeochemical properties. These approaches ignore the dispersal of species by oceanic circulation that can connect regions and isolates others. This dispersal effect can be quantified through connectivity that is the probability, or time of transport between distinct regions. Here a new regionalization method based on a connectivity approach is described and applied to the Mediterranean Sea. This method is based on an ensemble of Lagrangian particle numerical simulations using ocean model outputs at 1/12° resolution. The domain is divided into square subregions of 50 km size. Then particle trajectories are used to quantify the oceanographic distance between each subregions, here defined as the mean connection time. Finally the oceanographic distance matrix is used as a basis for a hierarchical clustering. 22 regions are retained and discussed together with a quantification of the stability of boundaries between regions. Identified regions are generally consistent with the general circulation with boundaries located along current jets or surrounding gyres patterns. Regions are discussed in the light of existing ecoregionalizations and available knowledge on plankton distributions. This objective method complements static regionalization approaches based on the environmental niche concept and can be applied to any oceanic region at any scale. PMID:25375212

  18. A connectivity-based eco-regionalization method of the Mediterranean Sea.

    PubMed

    Berline, Léo; Rammou, Anna-Maria; Doglioli, Andrea; Molcard, Anne; Petrenko, Anne

    2014-01-01

    Ecoregionalization of the ocean is a necessary step for spatial management of marine resources. Previous ecoregionalization efforts were based either on the distribution of species or on the distribution of physical and biogeochemical properties. These approaches ignore the dispersal of species by oceanic circulation that can connect regions and isolates others. This dispersal effect can be quantified through connectivity that is the probability, or time of transport between distinct regions. Here a new regionalization method based on a connectivity approach is described and applied to the Mediterranean Sea. This method is based on an ensemble of Lagrangian particle numerical simulations using ocean model outputs at 1/12° resolution. The domain is divided into square subregions of 50 km size. Then particle trajectories are used to quantify the oceanographic distance between each subregions, here defined as the mean connection time. Finally the oceanographic distance matrix is used as a basis for a hierarchical clustering. 22 regions are retained and discussed together with a quantification of the stability of boundaries between regions. Identified regions are generally consistent with the general circulation with boundaries located along current jets or surrounding gyres patterns. Regions are discussed in the light of existing ecoregionalizations and available knowledge on plankton distributions. This objective method complements static regionalization approaches based on the environmental niche concept and can be applied to any oceanic region at any scale.

  19. Biogeochemical regions of the Mediterranean Sea: An objective multidimensional and multivariate environmental approach

    NASA Astrophysics Data System (ADS)

    Reygondeau, Gabriel; Guieu, Cécile; Benedetti, Fabio; Irisson, Jean-Olivier; Ayata, Sakina-Dorothée; Gasparini, Stéphane; Koubbi, Philippe

    2017-02-01

    When dividing the ocean, the aim is generally to summarise a complex system into a representative number of units, each representing a specific environment, a biological community or a socio-economical specificity. Recently, several geographical partitions of the global ocean have been proposed using statistical approaches applied to remote sensing or observations gathered during oceanographic cruises. Such geographical frameworks defined at a macroscale appear hardly applicable to characterise the biogeochemical features of semi-enclosed seas that are driven by smaller-scale chemical and physical processes. Following the Longhurst's biogeochemical partitioning of the pelagic realm, this study investigates the environmental divisions of the Mediterranean Sea using a large set of environmental parameters. These parameters were informed in the horizontal and the vertical dimensions to provide a 3D spatial framework for environmental management (12 regions found for the epipelagic, 12 for the mesopelagic, 13 for the bathypelagic and 26 for the seafloor). We show that: (1) the contribution of the longitudinal environmental gradient to the biogeochemical partitions decreases with depth; (2) the partition of the surface layer cannot be extrapolated to other vertical layers as the partition is driven by a different set of environmental variables. This new partitioning of the Mediterranean Sea has strong implications for conservation as it highlights that management must account for the differences in zoning with depth at a regional scale.

  20. The Sinai subplate and tectonic evolution of the northern Red Sea region

    NASA Astrophysics Data System (ADS)

    Badawy, Ahmed; Horváth, Ferenc

    1999-03-01

    Although the precise boundaries and kinematics of the Sinai subplate are still doubtful, it has a significant role in the tectonic evolution of the northern Red Sea region. On the basis of earthquake distribution, the Sinai region can be considered as a subplate partially separated from the African plate by the Suez rift. The relative motion between Africa, Sinai and Arabia is the main source generating the present-day earthquake activity in the Gulf of Suez and the Gulf of Aqaba regions. According to geological observations, the southern segment of the Dead Sea fault system can be characterized by a left-lateral displacement of about 107km since the Middle Miocene, in contrast to the northern segment where only 25 to 35km offset can be inferred. We think that along the southern segment the total displacement was 72km until the late Miocene (10Ma). The earthquake activity is strongly reduced along the northern segment of the Dead Sea fault segment. Therefore, we suggest that the northern part (Yammouneh fault) evolves through initial cracking of the crust due to build-up of stress since the Pliocene time (5Ma) and propagates northward into Lebanon and Syria. This last 5 million years is the period when the southern and northern segments became linked and formed a single fault system with a new displacement of 35km. According to the proposed model the predicted opening pole of the Red Sea is near 34.0̊N, 22.0̊E with an angle of total rotation of 3.4̊ since the early miocene, providing a 0.82cm/a opening rate in the northern Red Sea. We suggest that the Dead Sea strike-slip fault was active since Middle Miocene time (15Ma) with a slip rate of 0.72cm/a to provide a total displacement of about 107km. This strike slip motion occured about an Euler pole near 33.0̊N, 21.0̊E with a rotation angle of about 3.0̊. It can be inferred from the proximity of the pole and angle of rotations for the Red Sea and Dead Sea fault that more than 85% of the motion has been

  1. Revisiting the contemporary sea-level budget on global and regional scales.

    PubMed

    Rietbroek, Roelof; Brunnabend, Sandra-Esther; Kusche, Jürgen; Schröter, Jens; Dahle, Christoph

    2016-02-09

    Dividing the sea-level budget into contributions from ice sheets and glaciers, the water cycle, steric expansion, and crustal movement is challenging, especially on regional scales. Here, Gravity Recovery And Climate Experiment (GRACE) gravity observations and sea-level anomalies from altimetry are used in a joint inversion, ensuring a consistent decomposition of the global and regional sea-level rise budget. Over the years 2002-2014, we find a global mean steric trend of 1.38 ± 0.16 mm/y, compared with a total trend of 2.74 ± 0.58 mm/y. This is significantly larger than steric trends derived from in situ temperature/salinity profiles and models which range from 0.66 ± 0.2 to 0.94 ± 0.1 mm/y. Mass contributions from ice sheets and glaciers (1.37 ± 0.09 mm/y, accelerating with 0.03 ± 0.02 mm/y(2)) are offset by a negative hydrological component (-0.29 ± 0.26 mm/y). The combined mass rate (1.08 ± 0.3 mm/y) is smaller than previous GRACE estimates (up to 2 mm/y), but it is consistent with the sum of individual contributions (ice sheets, glaciers, and hydrology) found in literature. The altimetric sea-level budget is closed by coestimating a remaining component of 0.22 ± 0.26 mm/y. Well above average sea-level rise is found regionally near the Philippines (14.7 ± 4.39 mm/y) and Indonesia (8.3 ± 4.7 mm/y) which is dominated by steric components (11.2 ± 3.58 mm/y and 6.4 ± 3.18 mm/y, respectively). In contrast, in the central and Eastern part of the Pacific, negative steric trends (down to -2.8 ± 1.53 mm/y) are detected. Significant regional components are found, up to 5.3 ± 2.6 mm/y in the northwest Atlantic, which are likely due to ocean bottom pressure variations.

  2. Revisiting the contemporary sea-level budget on global and regional scales

    PubMed Central

    Brunnabend, Sandra-Esther; Kusche, Jürgen; Schröter, Jens; Dahle, Christoph

    2016-01-01

    Dividing the sea-level budget into contributions from ice sheets and glaciers, the water cycle, steric expansion, and crustal movement is challenging, especially on regional scales. Here, Gravity Recovery And Climate Experiment (GRACE) gravity observations and sea-level anomalies from altimetry are used in a joint inversion, ensuring a consistent decomposition of the global and regional sea-level rise budget. Over the years 2002–2014, we find a global mean steric trend of 1.38 ± 0.16 mm/y, compared with a total trend of 2.74 ± 0.58 mm/y. This is significantly larger than steric trends derived from in situ temperature/salinity profiles and models which range from 0.66 ± 0.2 to 0.94 ± 0.1 mm/y. Mass contributions from ice sheets and glaciers (1.37 ± 0.09 mm/y, accelerating with 0.03 ± 0.02 mm/y2) are offset by a negative hydrological component (−0.29 ± 0.26 mm/y). The combined mass rate (1.08 ± 0.3 mm/y) is smaller than previous GRACE estimates (up to 2 mm/y), but it is consistent with the sum of individual contributions (ice sheets, glaciers, and hydrology) found in literature. The altimetric sea-level budget is closed by coestimating a remaining component of 0.22 ± 0.26 mm/y. Well above average sea-level rise is found regionally near the Philippines (14.7 ± 4.39 mm/y) and Indonesia (8.3 ± 4.7 mm/y) which is dominated by steric components (11.2 ± 3.58 mm/y and 6.4 ± 3.18 mm/y, respectively). In contrast, in the central and Eastern part of the Pacific, negative steric trends (down to −2.8 ± 1.53 mm/y) are detected. Significant regional components are found, up to 5.3 ± 2.6 mm/y in the northwest Atlantic, which are likely due to ocean bottom pressure variations. PMID:26811469

  3. Simulation of bombe radiocarbon transient in the Mediterranean Sea using a high-resolution regional model.

    NASA Astrophysics Data System (ADS)

    Ayache, Mohamed; Dutay, Jean-claude; Mouchet, Anne; Tisnérat-Laborde, Nadine; Houma-Bachari, Fouzia; Louanchi, Ferial; jean-baptiste, Philippe

    2016-04-01

    The radiocarbon isotope of carbon "14C", which a half-life of 5730 years, is continually formed naturally in the atmosphere by the neutron bombardment of 14N atoms. However, in the 1950s and early1960s, the atmospheric testing of thermonuclear weapons added a large amount of 14C into the atmosphere. The gradual infusion and spread of this "bomb" 14C through the oceans has provided a unique opportunity to gain insight into the specific rates characterizing the carbon cycle and ocean ventilations on such timescales. This numerical study provides, for the first time in the Mediterranean Sea, a simulation of the anthropogenic 14C invasion covers a 70-years period spanning the entire 14C generated by the bomb test, by using a high resolution regional model NEMO-MED12 (1/12° of horizontal resolution). This distribution and evolution of Δ14C of model is compared with recent high resolution 14C measurements obtained from surface water corals (Tisnérat-Laborde et al, 2013). In addition to providing constraints on the air-sea transfer of 14C, our work provides information on the thermohaline circulation and the ventilation of the deep waters to constrain the degree to which the NEMO-MED12 can reproduce correctly the main hydrographic features of the Mediterranean Sea circulation and its variations estimated from corals 14C time series measurements. This study is part of the work carried out to assess the robustness of the NEMO-MED12 model, which will be used to study the evolution of the climate and its effect on the biogeochemical cycles in the Mediterranean Sea, and to improve our ability to predict the future evolution of the Mediterranean Sea under the increasing anthropogenic pressure.

  4. Tsunami Simulations for Regional Sources in the South China and Adjoining Seas

    NASA Astrophysics Data System (ADS)

    Okal, Emile A.; Synolakis, Costas E.; Kalligeris, Nikos

    2011-06-01

    We present 14 scenarios of potential tsunamis in the South China Sea and its adjoining basins, the Sulu and Sulawezi Seas. The sources consist of earthquake dislocations inspired by the the study of historical events, either recorded (since 1900) or described in historical documents going back to 1604. We consider worst-case scenarios, where the size of the earthquake is not limited by the largest known event, but merely by the dimension of the basin over which a coherent fault may propagate. While such scenarios are arguably improbable, they may not be impossible, and as such must be examined. For each scenario, we present a simulation of the tsunami's propagation in the marine basin, exclusive of its interaction with the coastline. Our results show that the South China, Sulu and Sulawezi Seas make up three largely independent basins where tsunamis generated in one basin do not leak into another. Similarly, the Sunda arc provides an efficient barrier to tsunamis originating in the Indian Ocean. Furthermore, the shallow continental shelves in the Java Sea, the Gulf of Thailand and the western part of the South China Sea significantly dampen the amplitude of the waves. The eastern shores of the Malay Peninsula are threatened only by the greatest—and most improbable—of our sources, a mega-earthquake rupturing all of the Luzon Trench. We also consider two models of underwater landslides (which can be triggered by smaller events, even in an intraplate setting). These sources, for which there is both historical and geological evidence, could pose a significant threat to all shorelines in the region, including the Malay Peninsula.

  5. Regional and global sea-surface temperatures during the last interglaciation

    NASA Astrophysics Data System (ADS)

    Hoffman, Jeremy S.; Clark, Peter U.; Parnell, Andrew C.; He, Feng

    2017-01-01

    The last interglaciation (LIG, 129 to 116 thousand years ago) was the most recent time in Earth’s history when global mean sea level was substantially higher than it is at present. However, reconstructions of LIG global temperature remain uncertain, with estimates ranging from no significant difference to nearly 2°C warmer than present-day temperatures. Here we use a network of sea-surface temperature (SST) records to reconstruct spatiotemporal variability in regional and global SSTs during the LIG. Our results indicate that peak LIG global mean annual SSTs were 0.5 ± 0.3°C warmer than the climatological mean from 1870 to 1889 and indistinguishable from the 1995 to 2014 mean. LIG warming in the extratropical latitudes occurred in response to boreal insolation and the bipolar seesaw, whereas tropical SSTs were slightly cooler than the 1870 to 1889 mean in response to reduced mean annual insolation.

  6. High Arctic sea ice conditions influence marine birds wintering in Low Arctic regions

    NASA Astrophysics Data System (ADS)

    McFarlane Tranquilla, Laura; Hedd, April; Burke, Chantelle; Montevecchi, William A.; Regular, Paul M.; Robertson, Gregory J.; Stapleton, Leslie Ann; Wilhelm, Sabina I.; Fifield, David A.; Buren, Alejandro D.

    2010-09-01

    Ocean climate change is having profound biological effects in polar regions. Such change can also have far-reaching downstream effects in sub-polar regions. This study documents an environmental relationship between High Arctic sea ice changes and mortality events of marine birds in Low Arctic coastal regions. During April 2007 and March 2009, hundreds of beached seabird carcasses and moribund seabirds were found along the east and northeast coasts of Newfoundland, Canada. These seabird "wrecks" (i.e. dead birds on beaches) coincided with a period of strong, persistent onshore winds and heavily-accumulated sea ice that blocked bays and trapped seabirds near beaches. Ninety-two percent of wreck seabirds were Thick-billed Murres ( Uria lomvia). Body condition and demographic patterns of wreck murres were compared to Thick-billed Murres shot in the Newfoundland murre hunt. Average body and pectoral masses of wreck carcasses were 34% and 40% lighter (respectively) than shot murres, indicating that wreck birds had starved. The acute nature of each wreck suggested that starvation and associated hypothermia occurred within 2-3 days. In 2007, first-winter murres (77%) dominated the wreck. In 2009, there were more adults (78%), mostly females (66%). These results suggest that spatial and temporal segregation in ages and sexes can play a role in differential survival when stochastic weather conditions affect discrete areas where these groups aggregate. In wreck years, southward movement of Arctic sea ice to Low Arctic latitudes was later and blocked bays longer than in most other years. These inshore conditions corresponded with recent climate-driven changes in High Arctic ice break-up and ice extent; coupled with local weather conditions, these ice conditions appeared to be the key environmental features that precipitated the ice-associated seabird wrecks in the Low Arctic region.

  7. Faunistic Composition, Ecological Properties, and Zoogeographical Composition of the Elateridae (Coleoptera) Family in the Western Black Sea Region of Turkey

    PubMed Central

    Kabalak, Mahmut; Sert, Osman

    2013-01-01

    The main aim of this study was to understand the faunistic composition, ecological properties, and zoogeographical composition of the family Elateridae (Coleoptera) of the Western Black Sea region of Turkey. As a result, 44 species belonging to 5 subfamilies and 19 genera were identified. After adding species reported in the literature to the analysis, the fauna in the research area consists of 6 subfamilies, 23 genera and 72 species. Most of the Elateridae fauna of the Western Black Sea region were classified in the subfamilies Elaterinae and Dendrometrinae. The genus Athous was the most species-rich genus. The species composition of the Elateridae fauna of the Western Black Sea region partially overlaps with the known Elateridae fauna of Turkey. The Western Black Sea region shares the most species with the European part of the Western Palaearctic region, including many of those in the Elateridae family, compared to other regions. Comparisons of the three geographical regions of Turkey show that fauna composition, ecological properties, and zoogeographical compositions of the Middle and Western Black Sea regions are more similar to each other than to those of the Central Anatolian region. PMID:24787627

  8. The crustal structure of Egypt and the northern Red Sea region

    NASA Astrophysics Data System (ADS)

    Hosny, Ahmed; Nyblade, Andrew

    2016-09-01

    P-wave receiver functions from 26 stations in the Egyptian National Seismic Network (ENSN) have been modeled using the H-k stacking method and in a joint inversion method with Rayleigh wave group velocities to investigate crustal structure across Egypt and the northern Red Sea region. The new estimates of crustal structure, when combined with previous results, show that along the rifted margins of the Red Sea, Gulf of Suez and Gulf of Aqaba crustal thickness ranges from 25 to 30 km, the average crustal Vp/Vs ratio is 1.77, and the average crustal shear-wave velocity is 3.6 km/s. Beneath northern and central Egypt, including the Sinai Peninsula, crustal thickness ranges from 32 to 38 km, the average crustal Vp/Vs ratio is 1.79, and the average crustal shear-wave velocity is 3.5 km/s. Beneath southern Egypt, crustal thickness ranges from 35 to 40 km, the average crustal Vp/Vs ratio is 1.76, and the average crustal shear-wave velocity is 3.7 km/s. In southern Egypt, the crust is also characterized by a 10-20 km thick mafic lower crust. These findings indicate that crust along the rifted margins of the northern Red Sea, and Gulfs of Suez and Aqaba have been thinned by about 5 to 10 km. The thick mafic lower crust in southern Egypt can be attributed to suturing during the Neoproterozoic collision of east Gondwana against the Sahara metacraton. Overall, the structure of the crust in Egypt away from the northern Red Sea region is similar to the structure of Precambrian crust in many other parts of Africa.

  9. Timing and regional patterns of snowmelt on Antarctic sea ice from passive microwave satellite observations

    NASA Astrophysics Data System (ADS)

    Arndt, Stefanie; Willmes, Sascha; Dierking, Wolfgang; Nicolaus, Marcel

    2016-08-01

    An improved understanding of the temporal variability and the spatial distribution of snowmelt on Antarctic sea ice is crucial to better quantify atmosphere-ice-ocean interactions, in particular sea-ice mass and energy budgets. It is therefore important to understand the mechanisms that drive snowmelt, both at different times of the year and in different regions around Antarctica. In this study, we combine diurnal brightness temperature differences (dTB(37 GHz)) and ratios (TB(19 GHz)/TB(37 GHz)) to detect and classify snowmelt processes. We distinguish temporary snowmelt from continuous snowmelt to characterize dominant melt patterns for different Antarctic sea-ice regions from 1988/1989 to 2014/2015. Our results indicate four characteristic melt types. On average, 38.9 ± 6.0% of all detected melt events are diurnal freeze-thaw cycles in the surface snow layer, characteristic of temporary melt (Type A). Less than 2% reveal immediate continuous snowmelt throughout the snowpack, i.e., strong melt over a period of several days (Type B). In 11.7 ± 4.0%, Type A and B take place consecutively (Type C), and for 47.8 ± 6.8% no surface melt is observed at all (Type D). Continuous snowmelt is primarily observed in the outflow of the Weddell Gyre and in the northern Ross Sea, usually 17 days after the onset of temporary melt. Comparisons with Snow Buoy data suggest that also the onset of continuous snowmelt does not translate into changes in snow depth for a longer period but might rather affect the internal stratigraphy and density structure of the snowpack. Considering the entire data set, the timing of snowmelt processes does not show significant temporal trends.

  10. Body Size Versus Depth: Regional and Taxonomical Variation in Deep-Sea Meio- and Macrofaunal Organisms.

    PubMed

    van der Grient, Jesse M A; Rogers, Alex D

    2015-01-01

    Body size (weight per individual) is an important concept in ecology. It has been studied in the deep sea where a decrease in size with increasing depth has often been found. This has been explained as an adaptation to food limitation where size reduction results in a lowered metabolic rate and a decreased energetic requirement. However, observations vary, with some studies showing an increase in size with depth, and some finding no depth correlation at all. Here, we collected data from peer-reviewed studies on macro- and meiofaunal abundance and biomass, creating two datasets allowing statistical comparison of factors expected to influence body size in meio- and macrofaunal organisms. Our analyses examined the influence of region, taxonomic group and sampling method on the body size of meiofauna and macrofauna in the deep sea with increasing depth, and the resulting models are presented. At the global scale, meio- and macrofaunal communities show a decrease in body size with increasing depth as expected with the food limitation hypothesis. However, at the regional scale there were differences in trends of body size with depth, either showing a decrease (e.g. southwest Pacific Ocean; meio- and macrofauna) or increase (e.g. Gulf of Mexico; meiofauna only) compared to a global mean. Taxonomic groups also showed differences in body size trends compared to total community average (e.g. Crustacea and Bivalvia). Care must be taken when conducting these studies, as our analyses indicated that sampling method exerts a significant influence on research results. It is possible that differences in physiology, lifestyle and life history characteristics result in different responses to an increase in depth and/or decrease in food availability. This will have implications in the future as food supply to the deep sea changes as a result of climate change (e.g. increased ocean stratification at low to mid latitudes and reduced sea ice duration at high latitudes).

  11. The North Cycladic Detachment System and associated mineralization, Mykonos, Greece: Insights on the evolution of the Aegean domain

    NASA Astrophysics Data System (ADS)

    Menant, Armel; Jolivet, Laurent; Augier, Romain; Skarpelis, Nikolaos

    2013-06-01

    the Aegean back-arc domain, some 30-35 Ma ago, an increase of the rate of slab retreat led to the initiation of post-orogenic extension, largely accommodated by large-scale structures such as the North Cycladic Detachment System (NCDS). Although this extension is still active nowadays, an E-W compressional regime developed in the Late Miocene with the propagation of the North Anatolian Fault. On Mykonos island (Cyclades), the NE-SW back-arc extension is particularly well expressed with the Livada and Mykonos detachments that belong to the NCDS and that are associated with NW-SE barite veins emplaced during the synkinematic cooling of the Mykonos intrusion. This study shows that the formation of the mineralization occurred when the pluton crossed the ductile-to-brittle transition during its exhumation below the NCDS at ~11-10 Ma. In addition, the kinematics of mineralized structures evolved with time: (1) most of the displacement was accommodated by the top-to-the-NE Livada and Mykonos detachments accompanied by the formation of mineralized normal faults that were (2) reworked in a strike-slip regime with an E-W direction of shortening and a persistent NE-SW stretching and (3) a late post-mineralization E-W compressional stage with a minor reworking of shallow-dipping faults (locally including the detachments themselves). We interpret this increase of the E-W shortening component recorded during the mineral deposition as a consequence of the initiation of the westward motion of Anatolia from 10 Ma, thus 4 Ma before the propagation of the North Anatolian Fault in the Dardanelles Strait and the localization of the strain on the Aegean Sea margins.

  12. Much ado about SEA/SA monitoring: The performance of English Regional Spatial Strategies, and some German comparisons

    SciTech Connect

    Hanusch, Marie Glasson, John

    2008-11-15

    Strategic Environmental Assessment (SEA) seeks to better integrate environmental considerations into the preparation and decision-making process of plans and programmes with a view to promoting sustainable development. Further to application of the European Directive 2001/42/EC (SEA Directive) in 2004, the body of practical SEA experience, and parallel research, has increased steadily. Yet there is a crucial element of SEA which cannot build on much experience but whose importance will grow over time - namely that of SEA monitoring. The paper explores the application of SEA monitoring for English Regional Spatial Strategies (RSSs). It briefly introduces the role of SEA monitoring and its legal requirements, the English approach of integrating SEA into Sustainability Appraisal (SA) and the nature of the current English Regional Planning context. The main part presents the research findings and discusses how practitioners cope with the challenges of SEA/SA monitoring - with guiding questions: why, what, who, how, when, and with what outcomes? Reflecting that monitoring is just about to start, the paper draws on measures envisaged for monitoring in the SA reports prepared for RSS, and on expert interviews. It identifies monitoring trends and highlights workable approaches as well as shortcomings. For a critical reflection the findings are mirrored briefly with SEA monitoring approaches of German Regional Plans. Although it is still early days for such monitoring, the findings indicate that there is a danger that some of the specific requirements and objectives of SEA/SA monitoring are not fully met, mainly due to insufficient databases, inappropriate institutional conditions and limited personnel and financial resources. Some recommendations are offered in conclusion.

  13. Development of ramp-flat structures during Aegean extension

    NASA Astrophysics Data System (ADS)

    Brun, Jean-Pierre; Sokoutis, Dimitrios

    2014-05-01

    Low-angle extensional shear is frequently observed in the Aegean metamorphic rocks. This deformation is commonly interpreted as being related to detachment at crustal scale, yet it often corresponds to ramp-flat extensional systems that, at many places, control the deposition of Neogene sedimentary basins. From a mechanical point of view, the development of a ramp-flat structure requires the presence of weak layers that can be activated as décollement between stronger rocks units. In the Aegean, the décollement generally develops within the upper brittle crust (i.e. with temperatures lower than about 400°C) that consists in recently exhumed metamorphic rocks. The process by which, these layers become weak enough to form efficient décollements in extension is somewhat intriguing and not well understood. In this contribution we examine the particular case of ramp-flat structures of the Southern Rhodope Core Complex that controlled the deposition of late Miocene to Pleistocene sediments in continental and marine basins. Field evidence is used to argue that the décollement corresponds to marble layers that separate orthogneisses at 2-3 km depth within an upper brittle crust whose thickness is around 5 km. Field observation and stable isotope measurements suggest that the ramp-flat structure observed on the island of Thassos occurred in a marble unit rich in fluids at a temperature of around 200°C. Using laboratory experiments, we explore the geometry of extensional structures (fault systems, rollovers, piggy-back basins…) that can develop at crustal-scale as a function of: i) décollement depth and dip, ii) number of décollements, and iii) strength contrast, between the décollement and overlying strong units. The results are compared with the situation observed in the Southern Rhodope Core Complex. We are convinced that the principles of ramp-flat extension discussed here have a strong potential of application in many other orogenic domains affected by large

  14. Scientific support by the BONUS+ projects for the sustainability of the Baltic Sea Region: the case of the HELCOM Baltic Sea Action Plan.

    PubMed

    Kononen, Kaisa; Andrusaitis, Andris; Sirola, Maija

    2014-02-01

    The synthesis of the BONUS+ research is introduced. The HELCOM Baltic Sea Action Plan is examined as a case to illustrate the potentials and challenges in building the science-policy making interface on a macro regional level. The projects address environmental challenges in the Baltic Sea as defined by the Baltic Sea Action Plan, or consider the environmental governance and decision making within the Baltic Sea context in general. Eutrophication, biodiversity, hazardous substances, maritime activities, and the environment governance are addressed, as are cross cutting issues, such as the impact of climate change, maritime spatial planning and impacts of future development on ecosystem services. The projects contributed to relevant policy developments: 37 consultations carried out at EU level, 49 modifications to policy documents and action plans, 153 suggestions for the efficacy of pertinent public policies and governance, and in 570 occasions, scientists working in BONUS+ projects served as members or observers in scientific and stakeholder committees.

  15. Radioactive contamination of the Arctic Region, Baltic Sea, and the Sea of Japan from activities in the former Soviet Union

    SciTech Connect

    Bradley, D.J.

    1992-09-01

    Contamination of the Arctic regions of northern Europe and Russia, as well as the Sea of Japan, may become a potential major hazard to the ecosystem of these large areas. Widespread poor radioactive waste management practices from nuclear fuel cycle activities in the former Soviet Union have resulted in direct discharges to this area as well as multiple sources that may continue to release additional radioactivity. Information on the discharges of radioactive materials has become more commonplace in the last year, and a clearer picture is emerging of the scale of the contamination. Radioactivity in the Arctic oceans is now reported to be four times higher than would be derived from fallout from weapons tests. Although the characteristics and extent of the contamination are not well known, it has been stated that the contamination in the Arctic may range from 1 to 3.5 billion curies. As yet, no scientific sampling or measurement program has occurred that can verify the amount or extent of the contamination, or its potential impact on the ecosystem.

  16. Active geodynamics of the Marmara Sea region: How to combine all geophysical observations?

    NASA Astrophysics Data System (ADS)

    Karabulut, Hayrullah; Schmittbuhl, Jean; Lengliné, Olivier; Bouchon, Michel

    2016-04-01

    The Marmara Sea region is presently hosting a major seismic gap along the North Anatolian Fault (NAF). The region is located at the western termination of a unique sequence of large earthquakes initiated by the 1939 Mw 7.9 Erzincan earthquake and propagated westwards over 1000 km. Understanding the active geodynamics of the Marmara region is essential to assess the seismic behaviour of the Main Marmara Fault (MMF) and its related structures. We therefore have taken an initiative to give a comprehensive view of the regional lithosphere and the geomechanical response of the fault trying to combine all important geophysical observations. Using the broadband seismic data acquired between 2007-2015, we computed crustal seismic velocity distribution (from ambient noise tomography), crustal thickness map (from receiver function analysis) and uppermost mantle velocity distribution (from Pn tomography). The vast amount of data provides a good spatial coverage of the region and high resolution of images. Along the Main Marmara Fault (MMF), we present the seismicity below the Marmara Sea for the period the 2006-2015 to provide insights on the seismic response of the fault. The analysis shows that the seismic behaviour is varying along the fault. In addition, long term repeating earthquakes are searched along the MMF and found in the western part of the MMF. In the light of accurate and extensive observations, several open questions emerge from this compilation: Is the cumulated seismic moment released by the repeaters comparable to tectonic rate of the fault in the region? Are there any correlations between the rheology of the crust and the seismic response of the fault? Is there an influence of the fault asymmetry on the fault rupture?

  17. Regionally coupled atmosphere-ocean-sea ice-marine biogeochemistry model ROM: 1. Description and validation

    NASA Astrophysics Data System (ADS)

    Sein, Dmitry V.; Mikolajewicz, Uwe; Gröger, Matthias; Fast, Irina; Cabos, William; Pinto, Joaquim G.; Hagemann, Stefan; Semmler, Tido; Izquierdo, Alfredo; Jacob, Daniela

    2015-03-01

    The general circulation models used to simulate global climate typically feature resolution too coarse to reproduce many smaller-scale processes, which are crucial to determining the regional responses to climate change. A novel approach to downscale climate change scenarios is presented which includes the interactions between the North Atlantic Ocean and the European shelves as well as their impact on the North Atlantic and European climate. The goal of this paper is to introduce the global ocean-regional atmosphere coupling concept and to show the potential benefits of this model system to simulate present-day climate. A global ocean-sea ice-marine biogeochemistry model (MPIOM/HAMOCC) with regionally high horizontal resolution is coupled to an atmospheric regional model (REMO) and global terrestrial hydrology model (HD) via the OASIS coupler. Moreover, results obtained with ROM using NCEP/NCAR reanalysis and ECHAM5/MPIOM CMIP3 historical simulations as boundary conditions are presented and discussed for the North Atlantic and North European region. The validation of all the model components, i.e., ocean, atmosphere, terrestrial hydrology, and ocean biogeochemistry is performed and discussed. The careful and detailed validation of ROM provides evidence that the proposed model system improves the simulation of many aspects of the regional climate, remarkably the ocean, even though some biases persist in other model components, thus leaving potential for future improvement. We conclude that ROM is a powerful tool to estimate possible impacts of climate change on the regional scale.

  18. A 21-Year Record of Arctic Sea Ice Extents and Their Regional, Seasonal, and Monthly Variability and Trends

    NASA Technical Reports Server (NTRS)

    Parkinson, Claire L.; Cavalieri, Donald J.; Zukor, Dorothy J. (Technical Monitor)

    2001-01-01

    Satellite passive-microwave data have been used to calculate sea ice extents over the period 1979-1999 for the north polar sea ice cover as a whole and for each of nine regions. Over this 21-year time period, the trend in yearly average ice extents for the ice cover as a whole is -32,900 +/- 6,100 sq km/yr (-2.7 +/- 0.5 %/decade), indicating a reduction in sea ice coverage that has decelerated from the earlier reported value of -34,000 +/- 8,300 sq km/yr (-2.8 +/- 0.7 %/decade) for the period 1979-1996. Regionally, the reductions are greatest in the Arctic Ocean, the Kara and Barents Seas, and the Seas of Okhotsk and Japan, whereas seasonally, the reductions are greatest in summer, for which season the 1979-1999 trend in ice extents is -41,600 +/- 12,900 sq km/ yr (-4.9 +/- 1.5 %/decade). On a monthly basis, the reductions are greatest in July and September for the north polar ice cover as a whole, in September for the Arctic Ocean, in June and July for the Kara and Barents Seas, and in April for the Seas of Okhotsk and Japan. Only two of the nine regions show overall ice extent increases, those being the Bering Sea and the Gulf of St. Lawrence.For neither of these two regions is the increase statistically significant, whereas the 1079 - 1999 ice extent decreases are statistically significant at the 99% confidence level for the north polar region as a whole, the Arctic Ocean, the Seas of Okhotsk and Japan, and Hudson Bay.

  19. Preliminary report on shallow research drilling in the Salton Sea region

    SciTech Connect

    Newmark, R.L.; Kasameyer, P.W.; Younker, L.W.

    1988-01-14

    During two shallow thermal drilling programs, thermal measurements were obtained in 56 shallow (76.2 m) and one intermediate (457.3 m) depth holes located both onshore and offshore along the southern margin of the Salton Sea in the Imperial Valley, California. These data complete the surficial coverage of the thermal anomaly, revealing the shape and lateral extent of the hydrothermal system. The thermal data show the region of high thermal gradients to extend only a short distance offshore to the north of the Quaternary volcanic domes which are exposed along the southern shore of the Salton Sea. The central thermal anomaly has an arcuate shape, about 4 km wide and 12 km long. Across the center of the anomaly, the transition zone between locations exhibiting high thermal gradients and those exhibiting regional thermal gradients is quite narrow. Thermal gradients rise from near regional (0.09/degree/C/m) to extreme (0.83/degree/C/m) in only 2.4 km. The heat flow in the central part of the anomaly is greater than 600 mW/m/sup 2/ and in some areas exceeds 1200 mW/m/sup 2/. The shape of the thermal anomaly is asymmetric with respect to the line of volcanoes previously thought to represent the center of the field, with its center line offset south of the volcanic buttes. There is no broad thermal anomaly associated with the magnetic high that extends offshore to the northeast from the volcanic domes.

  20. Short-term Inundation Forecasting for Tsunamis in the Caribbean Sea Region

    NASA Astrophysics Data System (ADS)

    Mercado-Irizarry, A.; Schmidt, W.

    2007-05-01

    After the 2004 Indian Ocean tsunami, the USA Congress gave a mandate to the National Oceanographic and Atmospheric Administration (NOAA) to assess the tsunami threat for all USA interests, and adapt to them the Short-term Inundation Forecasting for Tsunamis (SIFT) methodology first developed for the USA Pacific seaboard states. This methodology would be used with the DART buoys deployed in the Atlantic Ocean and Caribbean Sea. The first step involved the evaluation and characterization of the major tsunamigenic regions in both regions, work done by the US Geological Survey (USGS). This was followed by the modeling of the generation and propagation of tsunamis due to unit slip tsunamigenic earthquakes located at different locations along the tsunamigenic zones identified by the USGS. These pre-computed results are stored and are used as sources (in an inverse modeling approach using the DART buoys) for so-called Standby Inundation Models (SIM's) being developed for selected coastal cities in Puerto Rico, the US Virgin Islands, and others along the Atlantic seaboard of the USA. It is the purpose of this presentation to describe the work being carried out in the Caribbean Sea region, where two SIM's for Puerto Rico have already being prepared, allowing for near real-time assessment (less than 10 minutes after detection by the DART buoys) of the expected tsunami impact for two major coastal cities.

  1. Method of calculating tsunami travel times in the Andaman Sea region.

    PubMed

    Kietpawpan, Monte; Visuthismajarn, Parichart; Tanavud, Charlchai; Robson, Mark G

    2008-07-01

    A new model to calculate tsunami travel times in the Andaman Sea region has been developed. The model specifically provides more accurate travel time estimates for tsunamis propagating to Patong Beach on the west coast of Phuket, Thailand. More generally, the model provides better understanding of the influence of the accuracy and resolution of bathymetry data on the accuracy of travel time calculations. The dynamic model is based on solitary wave theory, and a lookup function is used to perform bilinear interpolation of bathymetry along the ray trajectory. The model was calibrated and verified using data from an echosounder record, tsunami photographs, satellite altimetry records, and eyewitness accounts of the tsunami on 26 December 2004. Time differences for 12 representative targets in the Andaman Sea and the Indian Ocean regions were calculated. The model demonstrated satisfactory time differences (<2 min/h), despite the use of low resolution bathymetry (ETOPO2v2). To improve accuracy, the dynamics of wave elevation and a velocity correction term must be considered, particularly for calculations in the nearshore region.

  2. Levels of organochlorine pesticide residues in butter samples collected from the Black Sea Region of Turkey.

    PubMed

    Aksoy, Abdurrahman; Dervisoglu, Muhammed; Guvenc, Dilek; Gul, Osman; Yazici, Fehmi; Atmaca, Enes

    2013-01-01

    The aim of the present study was to evaluate the levels of 9 organochlorine compounds (aldrin, hexachlorobenzene, 2,4-DDE, 4,4-DDE, 2,4-DDT, 4,4-DDT, and α-, β-, and γ-HCH) in butter samples collected in the Eastern, Middle and Western Black Sea Regions of Turkey between October 2009 and June 2010. The liquid-liquid extraction method was used to extract the organochlorine compounds from the samples and the measurements were performed by using a gas chromatograph-electron capture detector system. DDT metabolites, aldrin, hexachlorobenzene (HCB), and α-, and γ-HCH were not detected in the samples but β-HCH was detected in 3 of a total of 88 samples. In the first period, only one sample from the West Black Sea Region was β-HCH positive (0.014 mg kg(-1)). The other β-HCH positive samples collected in Middle and West Black Sea Regions in the second period had a concentration of 0.066 and 0.019 mg kg(-1), respectively. All concentrations of the detected compounds exceeded the legal limits of 0.003 mg kg(-1) for β-HCH, as prescribed by the Turkish Food Codex, and therefore pose a potential health risk for consumers. The contamination detected is most likely due to the past usage of β-HCH in agriculture and its long term persistence in the environment. These results strongly suggest that further research should be focused on the detection of pesticide residues in agricultural areas across the nation.

  3. Orientation of hatchling loggerhead sea turtles to regional magnetic fields along a transoceanic migratory pathway.

    PubMed

    Fuxjager, Matthew J; Eastwood, Brian S; Lohmann, Kenneth J

    2011-08-01

    Young loggerhead sea turtles (Caretta caretta) from the east coast of Florida, USA, undertake a transoceanic migration around the North Atlantic Gyre, the circular current system that flows around the Sargasso Sea. Previous experiments indicated that loggerhead hatchlings, when exposed to magnetic fields replicating those that exist at five widely separated locations along the migratory pathway, responded by swimming in directions that would, in each case, help turtles remain in the gyre and advance along the migratory route. In this study, hatchlings were exposed to several additional magnetic fields that exist along or outside of the gyre's northern boundary. Hatchlings responded to fields that exist within the gyre currents by swimming in directions consistent with their migratory route at each location, whereas turtles exposed to a field that exists north of the gyre had an orientation that was statistically indistinguishable from random. These results are consistent with the hypothesis that loggerhead turtles entering the sea for the first time possess a navigational system in which a series of regional magnetic fields sequentially trigger orientation responses that help steer turtles along the migratory route. By contrast, hatchlings may fail to respond to fields that exist in locations beyond the turtles' normal geographic range.

  4. Modification of misovortices during landfall in the Japan Sea coastal region

    NASA Astrophysics Data System (ADS)

    Kato, Ryohei; Kusunoki, Kenichi; Inoue, Hanako Y.; Arai, Ken-ichiro; Nishihashi, Masahide; Fujiwara, Chusei; Shimose, Ken-ichi; Mashiko, Wataru; Sato, Eiichi; Saito, Sadao; Hayashi, Syugo; Yoshida, Satoru; Suzuki, Hiroto

    2015-05-01

    Misovortices frequently occur near the coastline of the Japan Sea during wintertime cold air outbreaks, generally developing over the sea and moving inland. To clarify the behavior of misovortices during landfall, temporal changes in the intensity and tilt of 12 misovortices over the coastal region of the Japan Sea were investigated during the winters of 2010/11 and 2011/12 using an X-band Doppler radar. For 11 vortices whose diameters were more than twice the effective radar beamwidth, the temporal change in the peak tangential velocity at lower levels (averaged below 400 m AGL) was analyzed. It was found that 8 out of the 11 vortices decreased after progressing between 0 and 6 km inland. For the remaining three vortices, the patterns of Doppler velocity couplet became unclear between 0 and 5 km inland, suggesting that these vortices also decayed soon after landfall. For four of the vortices, for which the analysis of the temporal evolution of tilt with height was made possible by several successive volume scans, the forward tilt with height increased after landfall. This study showed that modification to both the intensity and tilt with height of misovortices occurred after landfall.

  5. Regional correlations in the South Caspian Sea -implications for stratigraphic nomenclature

    SciTech Connect

    Murphy, J. Rukhsara, K.

    1995-08-01

    Regional Correlations in the South Caspian Sea - Implications for Stratigraphic Nomenclature Detailed sequence boundary correlations in the South Caspian sea have led to a better understanding of the relationships between stratigraphic units identified in wells throughout the basin. With the aid of synthetic seismograms, used to tie the logs to the seismic data, lithologic units have been identified seismically and have been mapped across the basin. The synthetic seismograms were created from pseudo-sonic logs which were transformed from resistivity logs with the Faust equation. Checkshots and VSP surveys supplied the velocity control. The sequence boundary correlations revealed substantial facies changes across the basin and led to the creation of a new stratigraphic correlation chart which relates local formation names to their time correlative boundaries. A recognition of these facies changes has led to a better understanding of the lithologic relationships within the basin, the depositional history of the basin, and the source and distribution of potential reservoir sands. Previous well log correlations, made primarily by matching tops of sand and shale sequences, frequently crossed sequence boundaries mapped from seismic data. Lithologic units, deposited under similar geologic conditions, often looked the same but were not time equivalent. Seismic sequence analyses have shown that tectonic movements, as evidenced by rising domes, created barriers to sediment distribution and led to pronounced thickness changes on opposite sides of a high. New log correlations, incorporating these concepts, are helping to unravel the complex structural and stratigraphic history of the South Caspian Sea.

  6. Nutrient abatement potential and abatement costs of waste water treatment plants in the Baltic Sea region.

    PubMed

    Hautakangas, Sami; Ollikainen, Markku; Aarnos, Kari; Rantanen, Pirjo

    2014-04-01

    We assess the physical potential to reduce nutrient loads from waste water treatment plants in the Baltic Sea region and determine the costs of abating nutrients based on the estimated potential. We take a sample of waste water treatment plants of different size classes and generalize its properties to the whole population of waste water treatment plants. Based on a detailed investment and operational cost data on actual plants, we develop the total and marginal abatement cost functions for both nutrients. To our knowledge, our study is the first of its kind; there is no other study on this issue which would take advantage of detailed data on waste water treatment plants at this extent. We demonstrate that the reduction potential of nutrients is huge in waste water treatment plants. Increasing the abatement in waste water treatment plants can result in 70 % of the Baltic Sea Action Plan nitrogen reduction target and 80 % of the Baltic Sea Action Plan phosphorus reduction target. Another good finding is that the costs of reducing both nutrients are much lower than previously thought. The large reduction of nitrogen would cost 670 million euros and of phosphorus 150 million euros. We show that especially for phosphorus the abatement costs in agriculture would be much higher than in waste water treatment plants.

  7. Bioavailability of dissolved organic carbon linked with the regional carbon cycle in the East China Sea

    NASA Astrophysics Data System (ADS)

    Gan, Shuchai; Wu, Ying; Zhang, Jing

    2016-02-01

    The regional carbon cycle on continental shelves has created great interest recently due to the enigma of whether these areas are a carbon sink or a source. It is vital for a precise carbon cycle model to take the bioavailability of dissolved organic carbon (DOC) into account, as it impacts the sink and source capacity, especially on dynamic shelves such as the East China Sea. Nine bio-decomposition experiments were carried out to assess differences in the bioavailability of DOC. Samples were collected from different water masses in the East China Sea, such as the Coastal Current, the Taiwan Current, and the Kuroshio Current, as well as from the Changjiang (Yangtze River), the main contributor of terrestrial DOC in the East China Sea. This study aimed to quantify and qualify bioavailable DOC (BDOC) in the East China Sea. Both the degradation constant of BDOC and the carbon output from microorganisms have been quantitatively evaluated. Qualitatively, excitation-emission matrix fluorescence spectra (EEMs) were used to evaluate the intrinsic reasons for BDOC variation. By using EEMs in conjunction with parallel factor analysis (PARAFAC), five individual fluorescent components were identified in this study: three humic-like and two protein-like components (P1, P2). The highest P1 and P2 fluorescence intensities were recorded in the coastal water during a phytoplankton algal bloom, while the lowest intensities were recorded in the Changjiang estuary. Quantitatively, BDOC observed during the incubation ranged from 0 to 26.1 μM. The DOC degradation rate constant varied from 0 to 0.027 (d-1), and was lowest in the Changjiang and highest in algal bloom water and warm shelf water (the Taiwan current). The Taiwan Current and mixed shelf water were the major contributors of BDOC flux to the open ocean, and the East China Sea was a net source of BDOC to the ocean. The results verified the importance of BDOC in regional carbon cycle modeling. Combining the data of BDOC and EEMs

  8. Assessing Sea Level Rise Impacts on the Surficial Aquifer in the Kennedy Space Center Region

    NASA Astrophysics Data System (ADS)

    Xiao, H.; Wang, D.; Hagen, S. C.; Medeiros, S. C.; Warnock, A. M.; Hall, C. R.

    2014-12-01

    Global sea level rise in the past century due to climate change has been seen at an average rate of approximately 1.7-2.2 mm per year, with an increasing rate over the next century. The increasing SLR rate poses a severe threat to the low-lying land surface and the shallow groundwater system in the Kennedy Space Center in Florida, resulting in saltwater intrusion and groundwater induced flooding. A three-dimensional groundwater flow and salinity transport model is implemented to investigate and evaluate the extent of floods due to rising water table as well as saltwater intrusion. The SEAWAT model is chosen to solve the variable-density groundwater flow and salinity transport governing equations and simulate the regional-scale spatial and temporal evolution of groundwater level and chloride concentration. The horizontal resolution of the model is 50 m, and the vertical domain includes both the Surficial Aquifer and the Floridan Aquifer. The numerical model is calibrated based on the observed hydraulic head and chloride concentration. The potential impacts of sea level rise on saltwater intrusion and groundwater induced flooding are assessed under various sea level rise scenarios. Based on the simulation results, the potential landward movement of saltwater and freshwater fringe is projected. The existing water supply wells are examined overlaid with the projected salinity distribution map. The projected Surficial Aquifer water tables are overlaid with data of high resolution land surface elevation, land use and land cover, and infrastructure to assess the potential impacts of sea level rise. This study provides useful tools for decision making on ecosystem management, water supply planning, and facility management.

  9. Late Holocene sea level changes along the coast of Southwestern Turkey

    NASA Astrophysics Data System (ADS)

    Kızıldaǧ, Nilhan; Özdaş, Harun; Özel, Erdeniz

    2014-05-01

    A multi-disciplinary survey has been performed along the coast of southwestern Turkey in order to determine relative sea level changes during the Late Holocene. Especially, the submergence of harbour structures of the ancient coastal settlements provides noticeable evidence for eustatic sea level rise and/or tectonic subsidence. In addition, the traces of bioerosion produced by some organisms along the limestone coasts formed at mean sea level position represent a remarkable data of paleoshorelines. These traces can be found below the current sea level nowadays due to relative sea level rise. Both archaeological and biological data provide an important source on the amount and period of relative sea level rise along the coasts of southwestern Turkey-southeastern Aegean Sea. This region is under the influence of active tectonism as a result of the collision of the Arab-African and Eurasian plates. Thus, a large number of earthquakes have occurred in this zone which must have been an impact on submergence of ancient harbour structures and geomorphological formations. This area is located very important zone in terms of being tectonically active, having a large number of ancient coastal settlements, and consisting of limestone lithology. A number of submerged archaeological structures and bioerosion formations have been investigated by measuring the depths of remains with respect to the present sea level. By comparing the eustatic sea level change, current elevations and construction time of archaeological remains, which dated taking into account construction techniques and ceramic findings, we determine the amount of relative sea level change. In addition, numerous active faults have been detected by performing seismic survey. The results indicate that the vertical tectonic movement has much more effect on submergence of archaeological and geomorphological features than eustatic sea level rise. Uncovering the role of the tectonic movement and sea level changes on the

  10. Dispersal and behavior of pacific halibut hippoglossus stenolepis in the bering sea and Aleutian islands region

    USGS Publications Warehouse

    Seitz, A.C.; Loher, T.; Norcross, Brenda L.; Nielsen, J.L.

    2011-01-01

    Currently, it is assumed that eastern Pacific halibut Hippoglossus stenolepis belong to a single, fully mixed population extending from California through the Bering Sea, in which adult halibut disperse randomly throughout their range during their lifetime. However, we hypothesize that hali but dispersal is more complex than currently assumed and is not spatially random. To test this hypo thesis, we studied the seasonal dispersal and behavior of Pacific halibut in the Bering Sea and Aleutian Islands (BSAI). Pop-up Archival Transmitting tags attached to halibut (82 to 154 cm fork length) during the summer provided no evidence that individuals moved out of the Bering Sea and Aleutian Islands region into the Gulf of Alaska during the mid-winter spawning season, supporting the concept that this region contains a separate spawning group of adult halibut. There was evidence for geographically localized groups of halibut along the Aleutian Island chain, as all of the individuals tagged there displayed residency, with their movements possibly impeded by tidal currents in the passes between islands. Mid-winter aggregation areas of halibut are assumed to be spawning grounds, of which 2 were previously unidentified and extend the species' presumed spawning range ~1000 km west and ~600 km north of the nearest documented spawning area. If there are indeed independent spawning groups of Pacific halibut in the BSAI, their dynamics may vary sufficiently from those of the Gulf of Alaska, so that specifically accounting for their relative segregation and unique dynamics within the larger population model will be necessary for correctly predicting how these components may respond to fishing pressure and changing environmental conditions.?? Inter-Research 2011.

  11. Regional carbon and CO2 budgets of North Sea tidal estuaries

    NASA Astrophysics Data System (ADS)

    Volta, C.; Laruelle, G. G.; Regnier, P.

    2016-07-01

    This study presents the first regional application of the generic estuarine reactive-transport model C-GEM (Carbon-Generic Estuary Model) that is here combined with high-resolution databases to produce a carbon and CO2 budget for all tidal estuaries discharging into the North Sea. Steady-state simulations are performed for yearly-averaged conditions to quantify the carbon processing in the six main tidal estuaries Elbe, Ems, Humber, Scheldt, Thames, and Weser, which show contrasted physical and biogeochemical dynamics and contribute the most to the regional filter. The processing rates derived from these simulations are then extrapolated to the riverine carbon loads of all the other North Sea catchments intercepted by smaller tidal estuarine systems. The Rhine-Meuse estuarine system is also included in the carbon budget and overall, we calculate that the export of organic and inorganic carbon from tidal estuaries to the North sea amounts to 44 and 409 Gmol C yr-1, respectively, while 41 Gmol C are lost annually through CO2 outgassing. The carbon is mostly exported from the estuaries in its inorganic form (>90%), a result that reflects the low organic/inorganic carbon ratio of the riverine waters, as well as the very intense decomposition of organic carbon within the estuarine systems. Our calculations also reveal that with a filtering capacity of 15% for total carbon, the contribution of estuaries to the CO2 outgassing is relatively small. Organic carbon dynamics is dominated by heterotrophic degradation, which also represents the most important contribution to the estuarine CO2 evasion. Nitrification only plays a marginal role in the CO2 dynamics, while the contribution of riverine oversaturated waters to the CO2 outgassing is generally significant and strongly varies across systems.

  12. The influence of atmospheric circulation types on regional patterns of precipitation in Marmara (NW Turkey)

    NASA Astrophysics Data System (ADS)

    Baltacı, H.; Kındap, T.; Ünal, A.; Karaca, M.

    2017-02-01

    In this study, regional patterns of precipitation in Marmara are described for the first time by means of Ward's hierarchical cluster analysis. Daily values of winter precipitation data based on 19 meteorological stations were used for the period from 1960 to 2012. Five clusters of coherent zones were determined, namely Black Sea-Marmara, Black Sea, Marmara, Thrace, and Aegean sub-regions. To investigate the prevailing atmospheric circulation types (CTs) that cause precipitation occurrence and intensity in these five different rainfall sub-basins, objective Lamb weather type (LWT) methodology was applied to National Centers of Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) reanalysis of daily mean sea level pressure (MSLP) data. Precipitation occurrence suggested that wet CTs (i.e. N, NE, NW, and C) offer a high chance of precipitation in all sub-regions. For the eastern (western) part of the region, the high probability of rainfall occurrence is shown under the influence of E (SE, S, SW) atmospheric CTs. In terms of precipitation intensity, N and C CTs had the highest positive gradients in all the sub-basins of the Marmara. In addition, although Marmara and Black Sea sub-regions have the highest daily rainfall potential during NE types, high daily rainfall totals are recorded in all sub-regions except the Black Sea during NW types.

  13. Simulation of 1986 South China Sea Monsoon with a Regional Climate Model

    NASA Technical Reports Server (NTRS)

    Tao, W. -K.; Lau, W. K.-M.; Jia, Y.; Juang, H.; Wetzel, P.; Qian, J.; Chen, C.

    1999-01-01

    A Regional Land-Atmosphere Climate Simulation System (RELACS) project is being developed at NASA Goddard Space Flight Center. One of the major goals of RELACS is to use a regional scale model with improved physical processes and in particular land-related processes, to understand the role of the land surface and its interaction with convection and radiation as well as the water/energy cycles in the IndoChina/South China Sea (SCS) region. The Penn State/NCAR MM5 atmospheric modeling system, a state of the art atmospheric numerical model designed to simulate regional weather and climate, has been successfully coupled to the Parameterization for Land-Atmosphere-Cloud Exchange (PLACE) land surface model. The original MM5 model (without PLACE) includes the option for either a simple slab soil model or a five-layer soil model (MRF) in which the soil moisture availability evolves over time. However, the MM5 soil models do not include the effects of vegetation, and thus important physical processes such as evapotranspiration and interception are precluded. The PLACE model incorporates vegetation type and has been shown in international comparisons to accurately predict evapotranspiration and runoff over a wide variety of land surfaces. The coupling of MM5 and PLACE creates a numerical modeling system with the potential to more realistically simulate atmosphere and land surface processes including land-sea interaction, regional circulations such as monsoons, and flash flood events. In addition, the Penn State/NCAR MM5 atmospheric modeling system has been: (1) coupled to the Goddard Ice Microphysical scheme; (2) coupled to a turbulent kinetic energy (TKE) scheme; (3) modified to ensure cloud budget balance; and (4) incorporated initialization with the Goddard EOS data sets at NASA/Goddard Laboratory for Atmospheres. The improved MM5 with two nested domains (60 and 20 km horizontal resolution) was used to simulate convective activity over IndoChina and the South China Sea

  14. Toward breeding new land-sea plant hybrid species irrigable with seawater for dry regions

    PubMed Central

    Moustafa, Khaled

    2015-01-01

    A plant species growing in sea or coastal saltmarsh is greatly tolerant to high concentrations of salts, and a plant species growing in desert or dry regions is highly tolerant to drought. Breeding a new plant hybrid species from both species by means of cellular grafting, genome fusion or nuclear transfer would generate, at least in theory, a hybrid plant species that should be strongly tolerant to harsh aridity and salinity and would be potentially irrigable with seawater. Such prospective species can be used for example as a fodder, biofuel crop or stabilizer species to protect soil from wind erosion and sandy storms in dry regions. Breeding such species would change the surface of the world and help to solve major challenges of starvation, malnutrition and poverty. Here, I propose potential approaches that would be worthy of investigation toward this purpose. PMID:25806436

  15. Sea breeze regimes in the New York City region - modeling and radar observations

    SciTech Connect

    Michael, P.; Miller, M.; Tongue, J.S.

    1998-04-01

    During spring and summer, the well known sea breeze circulations can strongly influence airport operations, air-quality, energy utilization, marine activities and infrastructure. The geographic configuration of the New York City region presents a special challenge to atmospheric prediction and analysis. The New Jersey and Long Island coasts are at approximate right angles to each other, additionally Long Island is separated from the mainland of Connecticut by Long Island Sound. The various bodies of water in the region (Atlantic Ocean, Long Island Sound, New York Harbor, Jamaica Bay, etc.) have different surface temperatures. In addition the urbanization of the New York areas can modify atmospheric flows. This paper will present results from model simulations, surface observations and remote sensing using the Weather Surveillance Radar - 1988 Doppler (WSR-88D).

  16. Toxic and essential elements in butter from the Black Sea region, Turkey.

    PubMed

    Dervisoglu, Muhammet; Gul, Osman; Yazici, Fehmi; Guvenc, Dilek; Atmaca, Enes; Aksoy, Abdurrahman

    2014-01-01

    In this study, 88 randomly selected samples of butter produced in the Black Sea region of Turkey were purchased from different retail markets during different periods and investigated for toxic and essential elements content. Quantitative analyses of elements in the samples were performed using an inductively coupled plasma-mass spectroscopy (ICP-MS). Mean concentrations of As, Cr, Cu, Fe, Mn, Ni, Pb, Se and Zn in the butter samples were 18.93, 100.32, 384.66, 4199.1, 887.47, 168.64, 56.13, 16.34 and 384.66 µg kg(-1), respectively. Cd and Co were detected in 19 (mean content 0.29 µg kg(-1)) and 81 (mean content 3.81 µg kg(-1)) samples of 88 butter samples, respectively. However, the dietary intake of these elements by the population of the Black Sea region is currently well below the dietary reference intake (DRI) and provisional tolerable weekly intake (PTWI) levels of essential and toxic elements.

  17. Mitochondrial control region haplotypes of the South American sea lion Otaria flavescens (Shaw, 1800).

    PubMed

    Artico, L O; Bianchini, A; Grubel, K S; Monteiro, D S; Estima, S C; Oliveira, L R de; Bonatto, S L; Marins, L F

    2010-09-01

    The South American sea lion, Otaria flavescens, is widely distributed along the Pacific and Atlantic coasts of South America. However, along the Brazilian coast, there are only two nonbreeding sites for the species (Refúgio de Vida Silvestre da Ilha dos Lobos and Refúgio de Vida Silvestre do Molhe Leste da Barra do Rio Grande), both in Southern Brazil. In this region, the species is continuously under the effect of anthropic activities, mainly those related to environmental contamination with organic and inorganic chemicals and fishery interactions. This paper reports, for the first time, the genetic diversity of O. flavescens found along the Southern Brazilian coast. A 287-bp fragment of the mitochondrial DNA control region (D-loop) was analyzed. Seven novel haplotypes were found in 56 individuals (OFA1-OFA7), with OFA1 being the most frequent (47.54%). Nucleotide diversity was moderate (π = 0.62%) and haplotype diversity was relatively low (67%). Furthermore, the median joining network analysis indicated that Brazilian haplotypes formed a reciprocal monophyletic clade when compared to the haplotypes from the Peruvian population on the Pacific coast. These two populations do not share haplotypes and may have become isolated some time back. Further genetic studies covering the entire species distribution are necessary to better understand the biological implications of the results reported here for the management and conservation of South American sea lions.

  18. Potential new production in two upwelling regions of the western Arabian Sea: Estimation and comparison

    NASA Astrophysics Data System (ADS)

    Liao, Xiaomei; Zhan, Haigang; Du, Yan

    2016-07-01

    Using satellite-derived and in situ data, the wind-driven potential new production (nitrate supply) for the 300 km wide coastal band in two upwelling regions of the western Arabian Sea (AS) during the southwest monsoon is estimated. The upward nitrate flux to the euphotic zone is generally based on the physical processes of coastal transport (Ekman transport and geostrophic transport) and offshore Ekman pumping. The coastal geostrophic current in the western AS influences the upwelling intensity and latitudinal distributions of nitrate supply. The Oman and Somalia upwelling regions have similar level of potential new production (nitrate supply) during the summer monsoon, while the satellite estimates of primary production off Oman are 2 times greater than those off Somalia. The much higher potential f-ratio in the Somalia upwelling region indicates that the primary production could be limited by availability of other macronutrients (e.g., silicate). The correlation analysis of the primary production and the aerosol optical thickness shows that the Oman upwelling region displays a stronger coupling between the atmospheric deposition and the phytoplankton abundance. The high summertime dust levels in the atmosphere are suggested to contribute to the high primary production in the Oman upwelling region.

  19. Polyphased rifting to post-breakup evolution of the Coral Sea region, Papua New Guinea

    NASA Astrophysics Data System (ADS)

    Bulois, Cédric; Pubellier, Manuel; Chamot-Rooke, Nicolas; Delescluse, Matthias

    2016-04-01

    region underwent thermal subsidence through the Middle Eocene prior the first regional compressional episode (Late Eocene to Oligocene). Rift-megacycles, although poorly dated, are probably pulsed, implying that internal sequences are of specific nature and age and are bounded by unconformities. The controlling factors may include the distribution of underlying basement highs and the response to regional stress variation driven by plate motion. In particular, the set of unconformities is thought to mark a series of uplift episodes that characterise the initiation of the rifting, or else seafloor spreading and subsidence (tectonic/thermal) during each specific rift megacycle. The current study more specifically shows that: (1) the early rifting phases of the crust (R1 and R2) were controlled by pre-existing continental features whereas the late Coral Sea propagator (R3) cut through the rifted margin independently from earlier structural trends. This last rifting is also more restricted to the area near the continent-ocean transition. (2) the set of rifted basins of the northern margin of the Coral Sea are now underthrusted below the Owen Stanley Basin initially located northward.

  20. Paleoecology of late-glacial peats from the bering land bridge, Chukchi Sea shelf region, northwestern Alaska

    USGS Publications Warehouse

    Elias, S.A.; Short, S.K.; Phillips, R.L.

    1992-01-01

    Insect fossils and pollen from late Pleistocene nonmarine peat layers were recovered from cores from the shelf region of the Chukchi Sea at depths of about 50 m below sea level. The peats date to 11,300-11,000 yr B.P. and provide a limiting age for the regional Pleistocene-Holocene marine transgression. The insect fossils are indicative of arctic coastal habitats like those of the Mackenzie Delta region (mean July temperatures = 10.6-14??C) suggesting that 11,000 yr ago the exposed Chukchi Sea shelf had a climate substantially warmer than modern coastal regions of the Alaskan north slope. The pollen spectra are consistent with the age assignment to the Birch Interval (14,000-9000 yr B.P.). The data suggest a meadow-like graminoid tundra with birch shrubs and some willow shrubs growing in sheltered areas. ?? 1992.

  1. Inferences on the Mesozoic evolution of the North Aegean from the isotopic record of the Chalkidiki block

    NASA Astrophysics Data System (ADS)

    Kydonakis, Konstantinos; Brun, Jean-Pierre; Poujol, Marc; Monié, Patrick; Chatzitheodoridis, Elias

    2016-07-01

    The Chalkidiki block is a major domain in the North Aegean that, contrary to other domains in the region, largely escaped thermal perturbations during Tertiary extension. As a result, the Chalkidiki block is an ideal candidate to glean information related to the timing of Mesozoic thermal events using appropriate geochronological techniques. We have undertaken a laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) study (U-Th-Pb on monazites and U-Pb on zircons) coupled with 40Ar/39Ar dating on nine samples from various structural levels within the thrust system of the Chalkidiki block. The eastern, and structurally lower part of the system revealed a complete isotopic reset of Carboniferous - Early Triassic monazites coeval with partial monazite destruction, REE-mobilisation and formation of apatite-allanite-epidote coronas at ~ 132 Ma, a reaction that is commonly observed in amphibolite-facies rocks. These coronas formed after crystallisation of garnet (i.e., at T > 580 °C) and, in all probability, either close to the peak-temperature conditions (~ 620 °C) on a prograde path or during retrogression between the peak-temperature and the low-temperature boundary of the amphibolite facies. Cooling of these rocks and arrival at mid-crustal levels occurred at 95-100 Ma. By contrast, the western, and structurally uppermost part of the system went through the same event by 120-125 Ma. Further structural considerations with respect to medium-temperature geochronology data imply that syn-metamorphic thrusting must have ceased by early Late Cretaceous. We emphasize that, with the sole exception of the Chalkidiki block, no pre-45 Ma medium-temperature geochronology data are preserved in other North Aegean domains, a feature that is clearly related to the extension-induced thermal perturbation of the region during the Tertiary.

  2. Climatic variability of river outflow in the Pantanal region and the influence of sea surface temperature

    NASA Astrophysics Data System (ADS)

    Silva, Carlos Batista; Silva, Maria Elisa Siqueira; Ambrizzi, Tércio

    2016-03-01

    This paper investigates possible linear relationships between climate, hydrology, and oceanic surface variability in the Pantanal region (in South America's central area), over interannual and interdecadal time ranges. In order to verify the mentioned relations, lagged correlation analysis and linear adjustment between river discharge at the Pantanal region and sea surface temperature were used. Composite analysis for atmospheric fields, air humidity flux divergence, and atmospheric circulation at low and high levels, for the period between 1970 and 2003, was analyzed. Results suggest that the river discharge in the Pantanal region is linearly associated with interdecadal and interannual oscillations in the Pacific and Atlantic oceans, making them good predictors to continental hydrological variables. Considering oceanic areas, 51 % of the annual discharge in the Pantanal region can be linearly explained by mean sea surface temperature (SST) in the Subtropical North Pacific, Tropical North Pacific, Extratropical South Pacific, and Extratropical North Atlantic over the period. Considering a forecast approach in seasonal scale, 66 % of the monthly discharge variance in Pantanal, 3 months ahead of SST, is explained by the oceanic variables, providing accuracy around 65 %. Annual discharge values in the Pantanal region are strongly related to the Pacific Decadal Oscillation (PDO) variability (with 52 % of linear correlation), making it possible to consider an interdecadal variability and a consequent subdivision of the whole period in three parts: 1st (1970-1977), 2nd (1978-1996), and 3rd (1997-2003) subperiods. The three subperiods coincide with distinct PDO phases: negative, positive, and negative, respectively. Convergence of humidity flux at low levels and the circulation pattern at high levels help to explain the drier and wetter subperiods. During the wetter 2nd subperiod, the air humidity convergence at low levels is much more evident than during the other two

  3. Survival and arm abscission are linked to regional heterothermy in an intertidal sea star.

    PubMed

    Pincebourde, Sylvain; Sanford, Eric; Helmuth, Brian

    2013-06-15

    Body temperature is a more pertinent variable to physiological stress than ambient air temperature. Modeling and empirical studies on the impacts of climate change on ectotherms usually assume that body temperature within organisms is uniform. However, many ectotherms show significant within-body temperature heterogeneity. The relationship between regional heterothermy and the response of ectotherms to sublethal and lethal conditions remains underexplored. We quantified within-body thermal heterogeneity in an intertidal sea star (Pisaster ochraceus) during aerial exposure at low tide to examine the lethal and sublethal effects of temperatures of different body regions. In manipulative experiments, we measured the temperature of the arms and central disc, as well as survival and arm abscission under extreme aerial conditions. Survival was related strongly to central disc temperature. Arms were generally warmer than the central disc in individuals that survived aerial heating, but we found the reverse in those that died. When the central disc reached sublethal temperatures of 31-35°C, arms reached temperatures of 33-39°C, inducing arm abscission. The absolute temperature of individual arms was a poor predictor of arm abscission, but the arms lost were consistently the hottest at the within-individual scale. Therefore, the vital region of this sea star may remain below the lethal threshold under extreme conditions, possibly through water movement from the arms to the central disc and/or evaporative cooling, but at the cost of increased risk of arm abscission. Initiation of arm abscission seems to reflect a whole-organism response while death occurs as a result of stress acting directly on central disc tissues.

  4. Towards a unified modeling system of predicting the transport of radionuclides in coastal sea regions

    NASA Astrophysics Data System (ADS)

    Jung, Kyung Tae; Brovchenko, Igor; Maderich, Vladimir; Kim, Kyeong Ok; Qiao, Fangli

    2016-04-01

    We present in this talk a recent progress in developing a unified modeling system of predicting three-dimensional transport of radionuclides coupled with multiple-scale circulation, wave and suspended sediment modules, keeping in mind the application to coastal sea regions with non-uniform distribution of suspended and bed sediments of both cohesive and non-cohesive types. The model calculates the concentration fields of dissolved and particulate radionuclides in bottom sediment as well as in water column. The transfer of radioactivity between the water column and the pore water in the upper layer of the bottom sediment is governed by diffusion processes. The phase change between dissolved and particulate radionuclides is written in terms of absorption/desorption rates and distribution coefficients. The dependence of distribution coefficients is inversely proportional to the sediment particle size. The hydrodynamic numerical model SELFE that solves equations for the multiple-scale circulation, the wave action and sand transport on the unstructured grids has been used as a base model. We have extended the non-cohesive sediment module of SELFE to the form applicable to mixture of cohesive and non-cohesive sedimentary regimes by implementing an extended form of erosional rate and a flocculation model for the determination of settling velocity of cohesive flocs. Issues related to the calibration of the sediment transport model in the Yellow Sea are described. The radionuclide transport model with one-step transfer kinetics and single bed layer has been initially developed and then applied to Fukushima Daiichi nuclear accident. The model has been in this study verified through the comparison with measurements of 137Cs concentration in bed sediments. Preliminary application to the Yellow and East China Seas with a hypothetical release scenario are described. On-going development of the radionuclide transport model using two-step transfer kinetics and multiple bed layers

  5. [Hantavirus infection: two case reports from a province in the Eastern Black Sea Region, Turkey].

    PubMed

    Kaya, Selçuk; Yılmaz, Gürdal; Erensoy, Sükrü; Yağçı Çağlayık, Dilek; Uyar, Yavuz; Köksal, Iftihar

    2010-07-01

    Hantaviruses which are the members of Bunyaviridae, differ from other members of this family since they are transmitted to humans by rodents. More than 200.000 cases of hantavirus infections are reported annually worldwide. Hantaviruses can lead to two different types of infection in humans, namely, hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). HFRS is the most common type of hantavirus infection in Europe and Asia and the most common virus types are Dobrava, Puumala, Hantaan and Seoul. A total of 25 hantavirus suspected cases have been reported from the Western Black Sea region of Turkey and 12 of these were confirmed serologically as "Puumala" subtype. Serological tests such as indirect immunofluorescence assay (IFA), are used for diagnosis and typing of the hantaviruses, however, since cross-reactions are common between the subtypes, the results of these tests should be confirmed by other methods. In this report two cases with hantavirus infection defined serologically were presented. Two male patients, 55 and 50 years old, respectively, living in Giresun province of Eastern Black Sea region, Turkey, were admitted to the State Hospital with the complaints of fever, sweating and diarrhoea without blood or mucus. Since thrombocytopenia and renal failure were detected in these two cases, they were transferred to the University Hospital. Presence of fever, thrombocytopenia and renal failure, with no laboratory findings of a bacterial infection and no growth of microoorganisms in the clinical specimens, admittance of the patients during summer and history of being present in the fields, necessitated to rule out leptospirosis, Crimean Kongo hemorrhagic fever and hantavirus infection which were all endemic in our area. Further investigation of the serum samples at the National Reference Virology Laboratory by IFA (Hantavirus Mosaic-1, Euroimmun, Germany) revealed hantavirus IgM and IgG antibodies ≥ 1:100 titer and the results

  6. Seismological Segmentation of Halmahera Thrust, Molucca Sea Region, based on Large Earthquake Sequences

    NASA Astrophysics Data System (ADS)

    Shiddiqi, H. A.; Widiyantoro, S.; Nugraha, A. D.; Ramdhan, M.; Wiyono, S. H.; Wandono, W.

    2015-12-01

    The Molucca Sea region in eastern Indonesia is a complex tectonic region, where the arc-arc collision between the Sangihe and Halmahera arcs takes place. Two recent largest earthquakes occurred in this area are Mw 7.5, January 2007, and Mw 7.2, November 2014, that occurred 90 km to the north from the 2007 earthquake site. Both earthquakes occurred along the Halmahera thrust, however, the aftershock of the two events occurred in separated parts of the same fault. In this study, we aim to investigate the segmentation of the seismogenic zone in Molucca Sea by using seismological analysis. We employed teleseismic double-difference relocation using P- and S-wave arrival times from the Meteorological, Climatological, and Geophysical Agency of Indonesia (BMKG) and the International Seismological Centre (ISC) catalog. We used a 3D velocity model for the Indonesian region. Our relocation result revealed that aftershocks of the two events did not overlap each other. Although they have similar focal mechanisms with NNE-SSW direction, the aftershock patterns were different. While the 2014 event aftershock distribution is consistent with the strike direction inferred from the focal mechanism, the 2007 event aftershocks occurred in NEE-SWW direction. Furthermore we analyzed the spatial variation in b-value for different time ranges. The b-value analysis also showed two separated segments of low b-value anomaly around both events for each time range. We envisage that stress regime directions and geometries of the fault are different for both aftershock clusters. For this reason we analyzed focal mechanism data and found that fault segment around the 2014 event is steeper than that related to the 2007 event. We applied focal mechanism inversion to obtain the direction of stress and fault orientation, and found different stress directions for the two segments. While the northern part segment has maximum stress with SSE direction, the stress in the southern part is rotated in SE

  7. Hindcast storm events in the Bering Sea for the St. Lawrence Island and Unalakleet Regions, Alaska

    USGS Publications Warehouse

    Erikson, Li H.; McCall, Robert T.; van Rooijen, Arnold; Norris, Benjamin

    2015-01-01

    This study provides viable estimates of historical storm-induced water levels in the coastal communities of Gambell and Savoonga situated on St. Lawrence Island in the Bering Sea, as well as Unalakleet located at the head of Norton Sound on the western coast of Alaska. Gambell, Savoonga, and Unalakleet are small Native Villages that are regularly impacted by coastal storms but where little quantitative information about these storms exists. The closest continuous water-level gauge is at Nome, located more than 200 kilometers from both St. Lawrence Island and Unalakleet. In this study, storms are identified and quantified using historical atmospheric and sea-ice data and then used as boundary conditions for a suite of numerical models. The work includes storm-surge (temporary rise in water levels due to persistent strong winds and low atmospheric pressures) modeling in the Bering Strait region, as well as modeling of wave runup along specified sections of the coast in Gambell and Unalakleet. Modeled historical water levels are used to develop return periods of storm surge and storm surge plus wave runup at key locations in each community. It is anticipated that the results will fill some of the data void regarding coastal flood data in western Alaska and be used for production of coastal vulnerability maps and community planning efforts.

  8. Geological and geomechanical properties of the carbonate rocks at the eastern Black Sea Region (NE Turkey)

    NASA Astrophysics Data System (ADS)

    Ersoy, Hakan; Yalçinalp, Bülent; Arslan, Mehmet; Babacan, Ali Erden; Çetiner, Gözde

    2016-11-01

    Turkey located in the Alpine-Himalayan Mountain Belt has 35% of the natural stone reserves of the world and has good quality marble, limestone, travertine and onyx reserves especially in the western regions of the country. The eastern Black Sea Region with a 1.4 million meters cubes reserve has a little role on the natural stone production in the country. For this reason, this paper deals with investigation on the potential of carbonate stone in the region and determination of the geological and geo-mechanical properties of these rocks in order to provide economic contribution to the national economy. While the study sites are selected among the all carbonate rock sites, the importance as well as the representative of the sites were carefully considered for the region. After representative samples were analyzed for major oxide and trace element compositions to find out petrochemical variations, the experimental program conducted on rock samples for determination of both physical and strength properties of the carbonate rocks. The results of the tests showed that there are significant variations in the geo-mechanical properties of the studied rock groups. The density values vary from 2.48 to 2.70 gr/cm3, water absorption by weight values range from 0.07 to 1.15% and the apparent porosity of the carbonate rocks are between 0.19 and 3.29%. However, the values of the UCS shows variation from 36 to 80 MPa. Tensile and bending strength values range from 3.2 to 7.5 MPa and 6.0-9.2 MPa respectively. Although the onyx samples have the lowest values of apparent porosity and water absorption by weight, these samples do not have the highest values of UCS values owing to occurrence of the micro-cracks. The UCS values of the rock samples were also found after cycling tests However, the limestone samples have less than 5% deterioration after freezing-thawing and wetting-drying tests, but travertine and onyx samples have more than 15% deterioration. Exception of the apparent

  9. Estimation of sea surface temperature from remote sensing in the 11-13 micron window region

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Dalu, G.; Kunde, V. G.

    1974-01-01

    The Nimbus 3 and 4 IRIS spectral data in the 11-13 micron water vapor window region are analyzed to determine the sea surface temperature (SST). The high spectral resolution data of IRIS are averaged over approximately 1 micron wide intervals to simulate channels of a radiometer to measure the SST. Three channels are utilized to measure SST over cloud-free oceans. However, two of these channels are sufficient in routine SST determination. The differential absorption properties of water vapor in the two channels enable one to determine the water vapor absorption correction without detailed knowledge of the vertical profiles of temperature and water vapor. The feasibility of determining the SST is demonstrated globally with Nimbus 3 data where cloud-free areas can be selected with the help of albedo data from the MRIR experiment on board the same satellite.

  10. Antioxidant activities of Sarcodon imbricatum wildly grown in the Black Sea Region of Turkey

    PubMed Central

    Özen, Tevfik; Türkekul, İbrahim

    2010-01-01

    The antioxidant activities of the methanol extract of Sarcodon imbricatum wildly grown in the Black Sea Region of Turkey were investigated in this study. Antioxidant activities were evaluated in terms of total antioxidant activity, reducing power, metal chelating ability, inhibition of linoleic acid peroxidation, superoxide, peroxide and hydrogen peroxide scavenging effects. Various antioxidant activities were compared to references antioxidants such as α-tocopherol, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and trolox. In total antioxidant (12674.45 μmol α-tocopherol/g of extract), superoxide scavenging (53.74%) and peroxide scavenging activity (45.73%), the methanol extract of Sarcodon imbricatum showed stronger activity patterns than that of references antioxidants. Reducing power, metal chelating activity and free radical (DPPH•) scavenging activity was increased with the increasing concentration. The contents of total phenolic, flavonoid, anthocyanin, ascorbic acid, β-carotene and lycopene of Sarcodon imbricatum were determined and found to be noteworthy. PMID:20668572

  11. Relative sea level variations in the Chukchi region - Arctic Ocean - since the late Eocene

    NASA Astrophysics Data System (ADS)

    Hegewald, Anne; Jokat, Wilfried

    2013-03-01

    Relative sea level (RSL) variations are a result of tectonic activity, changing of the water volume in ocean basins (e.g. due to increasing/decreasing of ice volume, evaporation) and variations in regional to global climate, which influence erosional processes and material transport. We present multi-channel seismic data combined with dated sediment horizons from the Chukchi Shelf, Arctic Ocean. Based on a series of prograding sequences in the upper 4 km of sediments and the method of seismic sequence stratigraphy, we introduce the first RSL curve for the Chukchi region, beginning in the late Eocene (40 Ma). The comparison of the Chukchi RSL curve with the global RSL curve shows that RSL lowering events in the Chukchi region do not correlate with global events for the Eocene/Oligocene - early Miocene. Between the Eocene/Oligocene and the late Oligocene, the Chukchi RSL variations were small (< 100 m). Since the late Oligocene the Chukchi RSL increased until the opening of the Fram Strait in the early Miocene. We show that the Chukchi RSL variations are representative for the Arctic Ocean, and conclude that the Arctic Ocean was an isolated basin for the Eocene/Oligocene - early Miocene.

  12. Estimating the regional climate responses over river basins to changes in tropical sea surface temperature patterns

    NASA Astrophysics Data System (ADS)

    Tsai, Chii-Yun; Forest, Chris E.; Wagener, Thorsten

    2015-10-01

    We investigate how to identify and assess teleconnection signals between anomalous patterns of sea surface temperature (SST) changes and climate variables related to hydrologic impacts over different river basins. The regional climate sensitivity to tropical SST anomaly patterns is examined through a linear relationship given by the global teleconnection operator (GTO, also generally called a sensitivity matrix or an empirical Green's function). We assume that the GTO defines a multilinear relation between SST forcing and regional climate response of a target area. The sensitivities are computed based on data from a large ensemble of simulations using the NCAR Community Atmospheric Model version 3.1 (CAM 3.1). The linear approximation is evaluated by comparing the linearly reconstructed response with both the results from the full non-linear atmospheric model and observational data. The results show that the linear approximation can capture regional climate variability that the CAM 3.1 AMIP-style simulations produce at seasonal scales for multiple river basins. The linear method can be used potentially for estimating drought conditions, river flow forecasting, and agricultural water management problems.

  13. Relationship of spontaneous pneumothorax cases seen in Eastern Black Sea region with meteorological changes

    NASA Astrophysics Data System (ADS)

    Yamac, Mustafa Esat; Karapolat, Sami; Turkyilmaz, Atila; Seyis, Kubra Nur; Tekinbas, Celal

    2017-03-01

    The relationship of climate changes or weather conditions with the incidence of pneumothorax has been explored for many years. We aimed at revealing the effects of meteorological changes on the incidence of pneumothorax in the Eastern Black Sea region where spontaneous pneumothorax cases are seen relatively more frequently. The records of 195 subjects (179 males and 16 females) who had been monitored and treated due to spontaneous pneumothorax between January 2006 and December 2012 at our clinic were reviewed retrospectively, and their relationship was investigated with the meteorological data obtained by going through the database archive records of the 11th Regional Meteorology Directorate for the years between 2006 and 2012. Wind velocity was observed to be less in the days of having spontaneous pneumothorax than in the days of having no spontaneous pneumothorax, and the difference was found statistically significant (P = 0.026). The people of our region whose active lifestyle is reflected in their working life, social life, and even in their folk dances usually take a rest in the days of slower wind speed. We think that this state of resting leads to an increase in the frequency of spontaneous pneumothorax.

  14. Seasonal Storminess in the North Pacific, Bering Sea, and Alaskan Regions

    NASA Astrophysics Data System (ADS)

    Shippee, N. J.; Atkinson, D. E.; Walsh, J. E.; Partain, J.; Gottschalck, J.; Marra, J.

    2012-12-01

    Annually, extra-tropical cyclones present a high impact natural hazard to the North Pacific, Bering Sea, and Alaskan regions. In these regions, extensive subsistence and commercial fishing, new oil and gas field development, tourism, growing interest in and exploitation of new commercial shipping potential, and increasing military and Coast Guard activity, all represent potential parties impacted by storms in these waters. It is of interest to many parties to begin developing capacity to provide some indication of storm activity at a monthly- to seasonal-outlook (30 to 90 days) timeframe. Using storm track data from NOAA's Climate Prediction Center for the North Pacific and Alaskan region, an experimental seasonal storminess outlook product, using eigen-based methods similar to the operational seasonal temperature and precipitation products currently produced at NOAA CPC, has been created and tested in hindcast mode using predicted states of ENSO, the Pacific Decadal Oscillation (PDO), the Pacific-North American Pattern (PNA), and the Arctic Oscillation (AO). A sample of the seasonal storminess outlook product will be shown along with a discussion of the utility of individual teleconnection patterns in the generation of the product.

  15. Relationship of spontaneous pneumothorax cases seen in Eastern Black Sea region with meteorological changes.

    PubMed

    Yamac, Mustafa Esat; Karapolat, Sami; Turkyilmaz, Atila; Seyis, Kubra Nur; Tekinbas, Celal

    2017-03-03

    The relationship of climate changes or weather conditions with the incidence of pneumothorax has been explored for many years. We aimed at revealing the effects of meteorological changes on the incidence of pneumothorax in the Eastern Black Sea region where spontaneous pneumothorax cases are seen relatively more frequently. The records of 195 subjects (179 males and 16 females) who had been monitored and treated due to spontaneous pneumothorax between January 2006 and December 2012 at our clinic were reviewed retrospectively, and their relationship was investigated with the meteorological data obtained by going through the database archive records of the 11th Regional Meteorology Directorate for the years between 2006 and 2012. Wind velocity was observed to be less in the days of having spontaneous pneumothorax than in the days of having no spontaneous pneumothorax, and the difference was found statistically significant (P = 0.026). The people of our region whose active lifestyle is reflected in their working life, social life, and even in their folk dances usually take a rest in the days of slower wind speed. We think that this state of resting leads to an increase in the frequency of spontaneous pneumothorax.

  16. Multi-model seasonal forecast of Arctic sea-ice: forecast uncertainty at pan-Arctic and regional scales

    NASA Astrophysics Data System (ADS)

    Blanchard-Wrigglesworth, E.; Barthélemy, A.; Chevallier, M.; Cullather, R.; Fučkar, N.; Massonnet, F.; Posey, P.; Wang, W.; Zhang, J.; Ardilouze, C.; Bitz, C. M.; Vernieres, G.; Wallcraft, A.; Wang, M.

    2016-10-01

    Dynamical model forecasts in the Sea Ice Outlook (SIO) of September Arctic sea-ice extent over the last decade have shown lower skill than that found in both idealized model experiments and hindcasts of previous decades. Additionally, it is unclear how different model physics, initial conditions or forecast post-processing (bias correction) techniques contribute to SIO forecast uncertainty. In this work, we have produced a seasonal forecast of 2015 Arctic summer sea ice using SIO dynamical models initialized with identical sea-ice thickness in the central Arctic. Our goals are to calculate the relative contribution of model uncertainty and irreducible error growth to forecast uncertainty and assess the importance of post-processing, and to contrast pan-Arctic forecast uncertainty with regional forecast uncertainty. We find that prior to forecast post-processing, model uncertainty is the main contributor to forecast uncertainty, whereas after forecast post-processing forecast uncertainty is reduced overall, model uncertainty is reduced by an order of magnitude, and irreducible error growth becomes the main contributor to forecast uncertainty. While all models generally agree in their post-processed forecasts of September sea-ice volume and extent, this is not the case for sea-ice concentration. Additionally, forecast uncertainty of sea-ice thickness grows at a much higher rate along Arctic coastlines relative to the central Arctic ocean. Potential ways of offering spatial forecast information based on the timescale over which the forecast signal beats the noise are also explored.

  17. The Influence of Arctic Sea Ice Extent on Polar Cloud Fraction and Vertical Structure and Implications for Regional Climate

    NASA Technical Reports Server (NTRS)

    Palm, Stephen P.; Strey, Sara T.; Spinhirne, James; Markus, Thorsten

    2010-01-01

    Recent satellite lidar measurements of cloud properties spanning a period of five years are used to examine a possible connection between Arctic sea ice amount and polar cloud fraction and vertical distribution. We find an anti-correlation between sea ice extent and cloud fraction with maximum cloudiness occurring over areas with little or no sea ice. We also find that over ice free regions, there is greater low cloud frequency and average optical depth. Most of the optical depth increase is due to the presence of geometrically thicker clouds over water. In addition, our analysis indicates that over the last 5 years, October and March average polar cloud fraction has increased by about 7 and 10 percent, respectively, as year average sea ice extent has decreased by 5 to 7 percent. The observed cloud changes are likely due to a number of effects including, but not limited to, the observed decrease in sea ice extent and thickness. Increasing cloud amount and changes in vertical distribution and optical properties have the potential to affect the radiative balance of the Arctic region by decreasing both the upwelling terrestrial longwave radiation and the downward shortwave solar radiation. Since longwave radiation dominates in the long polar winter, the overall effect of increasing low cloud cover is likely a warming of the Arctic and thus a positive climate feedback, possibly accelerating the melting of Arctic sea ice.

  18. Influence of Arctic Sea Ice Extent on Polar Cloud Fraction and Vertical Structure and Implications for Regional Climate

    NASA Technical Reports Server (NTRS)

    Palm, Stephen P.; Strey, Sara T.; Spinhirne, James; Markus, Thorsten

    2010-01-01

    Recent satellite lidar measurements of cloud properties spanning a period of 5 years are used to examine a possible connection between Arctic sea ice amount and polar cloud fraction and vertical distribution. We find an anticorrelation between sea ice extent and cloud fraction with maximum cloudiness occurring over areas with little or no sea ice. We also find that over ice!free regions, there is greater low cloud frequency and average optical depth. Most of the optical depth increase is due to the presence of geometrically thicker clouds over water. In addition, our analysis indicates that over the last 5 years, October and March average polar cloud fraction has increased by about 7% and 10%, respectively, as year average sea ice extent has decreased by 5% 7%. The observed cloud changes are likely due to a number of effects including, but not limited to, the observed decrease in sea ice extent and thickness. Increasing cloud amount and changes in vertical distribution and optical properties have the potential to affect the radiative balance of the Arctic region by decreasing both the upwelling terrestrial longwave radiation and the downward shortwave solar radiation. Because longwave radiation dominates in the long polar winter, the overall effect of increasing low cloud cover is likely a warming of the Arctic and thus a positive climate feedback, possibly accelerating the melting of Arctic sea ice.

  19. Two regimes of cloud water over the Okhotsk Sea and the adjacent regions around Japan in summer

    NASA Astrophysics Data System (ADS)

    Shimada, Teruhisa; Iwasaki, Toshiki

    2015-03-01

    This study derived two regimes of cloud water with a dipole structure between over the Okhotsk Sea and over the adjacent regions around Japan in summer by using a climate index for cool summer. When the Okhotsk high develops, clouds are confined to a thin low-level layer owing to the enhanced stability in the lower atmosphere induced by the downward motion associated with the Okhotsk high. The resulting optically thin clouds allow more downward shortwave radiation to reach the surface of the Okhotsk Sea. In contrast, the low-level easterly winds blowing toward the Japanese Islands and the Eurasian continent enhance cloud formation. This is due to the convergence of the water vapor flux induced by the easterly winds associated with the Okhotsk high and the southerly winds associated with the Baiu frontal zone and the Pacific high and due to the orographic uplift of air mass. When a cyclonic circulation occurs over the Okhotsk Sea, a thick layer of low-level clouds extending close to the sea surface is formed. The convergence of the water vapor flux over the subarctic sea surface temperature (SST) frontal zone and the cool SST promote fog formation, and upward motion associated with the cyclonic circulation supports the high cloud water content from the lower to the upper troposphere. The resulting optically thick clouds reduce the downward shortwave radiation at the surface of the Okhotsk Sea. Over the regions around Japan, water vapor flux diverges owing to dry air originating from land and cloud water decreases.

  20. Lithofacies variability in the Lower Khvalynian sediments of the North Caspian Sea region.

    NASA Astrophysics Data System (ADS)

    Makshaev, Radik; Svitoch, Aleksandr

    2016-04-01

    The Early Khvalynian period (~15 500-12 500 cal years B.P.) is characterized by continuous dynamic changes in North Caspian Sea region environment, which has been confirmed by numerous data obtained during the lithofacies analysis of its key sections. Lithofacies complex of the North Caspian Sea region contains four subfacies - clayey, laminated, sandy-clayey and aleurite-clayey. Clayey facie is characterized by absolutely clayey structure with massive nonlamellated or subfissile dark-brown clays and rarely contains thin aleurite layers. This subfacie is one of the most widespread in the North Caspian Sea region. Clayey facies are typical for the most of the key sections in the Middle Volga (Bykovo, Torgun, Rovnoe, Novoprivolnoe, Chapaevka), Lower Volga (Svetly Yar) and on the left side of the Volga River valley (Verkhny Baskunchak, Krivaya Loshchina, Bolshoy Liman). Deep paleodepressions of the Lower Volga and the left side of the Volga River valley are also characterized by the maximum of the average clays thickness, which can reach up to 10 m. Sandy-clayey subfacie is characterized by stratified structure with horizontal and lenticular lamination of clays with sandy-aleuritic interlayers. The average thickness of sand layers is 2-5 cm. At most of the key sections thickness of clay layers is up to twice larger than the sands layers and only on depressions' periphery can be exceeded by some terrigenous interlayers. Sandy-aleuritic parts of clays have different mineral structure. Light suite is dominated by quartz and feldspar with some debris of heavy minerals, glauconite and calcite. Fraction of the heavy minerals contains titano ferrite, epidote, granite, zircon, amphibole, rutile, disthene, tourmaline, sillimanite. Layered subfacie is the most abundant among the chocolate clays and is widespread in the Lower Volga River region and the Ural River valley, but sporadic in Kalmykia and the Volga Delta. Sandy-clayey and aleurit-clayey subfacies have rare

  1. Localised vs distributed deformation: 3D modelling of the Dead Sea region

    NASA Astrophysics Data System (ADS)

    Devès, M. H.; King, G. C.; Klinger, Y.; Agnon, A.

    2012-12-01

    The lithosphere behaves as strain softening elasto-plastic materials. In the laboratory, such materials are known to deform in a brittle or a ductile manner depending on the applied geometric boundary conditions. In the lithosphere however, the importance of boundary conditions in controlling the deformation style has been largely ignored. Under general boundary conditions, both laboratory and field observations show that only part of the deformation can localise on through going faults while the rest must remain distributed in process zones where spatially varying shear directions inhibit localisation. Conventional modelling methods use rheologies deduced from laboratory experiments that are not constrained as a function of the geometry of the applied boundary conditions. We propose an alternative modelling method based on the use of an appropriate distribution of dislocation sources to create the deformation field. This approach, because it does not rely on integrating differential equations from more or less well-constrained boundary conditions, does not require making assumptions on the parameters controlling the level and distribution of stresses within the lithosphere. It only supposes that strain accumulates linearly away from the dislocation singularities satisfying the compatibility equations. We verify that this model explains important and hitherto unexplained features of the topography of the Dead Sea region. Following the idea that strain can only localise under specific conditions as inferred from laboratory and field scale observations, we use our model of deformation to predict where deformation can localise and where it has to remain distributed. We find that 65% of the deformation in the Dead Sea region can localise on kinematically stable through-going strike-slip faults while the remaining 35% must remain distributed. Observations suggest that distributed deformation occurs at stress levels that can be ten times greater than that associated with

  2. An improved earthquake catalogue in the Marmara Sea region, Turkey, using massive template matching

    NASA Astrophysics Data System (ADS)

    Matrullo, Emanuela; Lengliné, Olivier; Schmittbuhl, Jean; Karabulut, Hayrullah; Bouchon, Michel

    2016-04-01

    After the 1999 Izmit earthquake, the Main Marmara Fault (MMF) represents a 150 km unruptured segment of the North Anatolian Fault located below the Marmara Sea. One of the principal issue for seismic hazard assessment in the region is to know if the MMF is totally or partially locked and where the nucleation of the major forthcoming event is going to take place. The area is actually one of the best-instrumented fault systems in Europe. Since year 2007, various seismic networks both broadband, short period and OBS stations were deployed in order to monitor continuously the seismicity along the MMF and the related fault systems. A recent analysis of the seismicity recorded during the 2007-2012 period has provided new insights on the recent evolution of this important regional seismic gap. This analysis was based on events detected with STA/LTA procedure and manually picked P and S wave arrivals times (Schmittbuhl et al., 2015). In order to extend the level of details and to fully take advantage of the dense seismic network we improved the seismic catalog using an automatic earthquake detection technique based on a template matching approach. This approach uses known earthquake seismic signals in order to detect newer events similar to the tested one from waveform cross-correlation. To set-up the methodology and verify the accuracy and the robustness of the results, we initially focused in the eastern part of the Marmara Sea (Cinarcik basin) and compared new detection with those manually identified. Through the massive analysis of cross-correlation based on the template scanning of the continuous recordings, we construct a refined catalog of earthquakes for the Marmara Sea in 2007-2014 period. Our improved earthquake catalog will provide an effective tool to improve the catalog completeness, to monitor and study the fine details of the time-space distribution of events, to characterize the repeating earthquake source processes and to understand the mechanical state of

  3. Influence of sea-land breezes on the tempospatial distribution of atmospheric aerosols over coastal region.

    PubMed

    Tsai, Hsieh-Hung; Yuan, Chung-Shin; Hung, Chung-Hsuang; Lin, Chitsan; Lin, Yuan-Chung

    2011-04-01

    The influence of sea-land breezes (SLBs) on the spatial distribution and temporal variation of particulate matter (PM) in the atmosphere was investigated over coastal Taiwan. PM was simultaneously sampled at inland and offshore locations during three intensive sampling periods. The intensive PM sampling protocol was continuously conducted over a 48-hr period. During this time, PM2.5 and PM(2.5-10) (PM with aerodynamic diameters < 2.5 microm and between 2.5 and 10 microm, respectively) were simultaneously measured with dichotomous samplers at four sites (two inland and two offshore sites) and PM10 (PM with aerodynamic diameters < or =10 microm) was measured with beta-ray monitors at these same 4 sites and at 10 sites of the Taiwan Air Quality Monitoring Network. PM sampling on a mobile air quality monitoring boat was further conducted along the coastline to collect offshore PM using a beta-ray monitor and a dichotomous sampler. Data obtained from the inland sites (n=12) and offshore sites (n=2) were applied to plot the PM10 concentration contour using Surfer software. This study also used a three-dimensional meteorological model (Pennsylvania State University/National Center for Atmospheric Research Meteorological Model 5) and the Comprehensive Air Quality Model with Extensions to simulate surface wind fields and spatial distribution of PM10 over the coastal region during the intensive sampling periods. Spatial distribution of PM10 concentration was further used in investigating the influence of SLBs on the transport of PM10 over the coastal region. Field measurement and model simulation results showed that PM10 was transported back and forth across the coastline. In particular, a high PM10 concentration was observed at the inland sites during the day because of sea breezes, whereas a high PM10 concentration was detected offshore at night because of land breezes. This study revealed that the accumulation of PM in the near-ocean region because of SLBs influenced the

  4. Regional forecasting system of marine state and variability of dynamical processes in the easternmost part of the Black Sea

    NASA Astrophysics Data System (ADS)

    Kordzadze, Avtandil; Demetrashvili, Demuri

    2014-05-01

    The regional forecasting system for the easternmost part of the Black Sea developed at M. Nodia Institute of Geophysics of I. Javakhishvili Tbilisi State University under the EU framework projects ARENA and ECOOP is a part of the Black Sea basin-scale Nowcasting/Forecasting System. A core of the regional forecasting system is a baroclinic regional model of Black Sea dynamics with 1 km spacing based on hydrostatic primitive equations of ocean hydrothermodynamics, which are written in z-coordinates for deviations of thermodynamic values from their standard vertical distributions. To solve the problem the two-cycle method of splitting the model equation system with respect to both physical processes and coordinate planes and lines is used. The regional model of M. Nodia Institute of Geophysics is nested in the basin-scale model of Black Sea dynamics of Marine Hydrophysical Institute (Sevastopol/Ukraine). The regional forecasting system provides 3 days' forecasts of current, temperature and salinity for the easternmost part of the Black Sea, which is limited to the Caucasian and Turkish coastal lines and the western liquid boundary coinciding with the meridian 39.080E. Data needed on liquid and upper boundaries, also the 3-D initial hydrophysical fields for the easternmost regional area are provided in near operative mode from Marine hydrophysical Institute via Internet. These data on the liquid boundary are values of velocity components, temperature and salinity predicted by the basin-scale model of Black Sea dynamics of Marine Hydrophysical Institute and on the sea surface 2-D meteorological boundary fields - wind stress, heat fluxes, evaporation and precipitation rates predicted by the regional atmospheric model ALADIN are used. The analysis of the results of modeling and forecast of dynamic processes developed for 2010-2014 showed that the easternmost water area of the Black Sea is a dynamically very active zone, where continuously there are processes of generation

  5. Patterns of sperm-specific histone variation in sea stars and sea urchins: primary structural homologies in the N-terminal region of spermatogenic H1.

    PubMed

    Massey, C B; Watts, S A

    1992-04-15

    An electrophoretic characterization of histones from pyloric caeca, testes, and sperm of Asterias vulgaris revealed a sperm/testes-specific variant of histone H1 significantly larger than its somatic counterpart from pyloric caeca. Additional proteins were observed in H1 regions of acetic acid-urea polyacrylamide gels in testicular extracts. Sperm or testis-specific variants of H2B observed in sea urchins were not found in the sea star. Evidence presented suggests that sperm- or testes-specific H1 species of intermediate mobility may arise from a single, slow-migrating H1 species (SpH1). Although an increase in nonspecific DNA binding by nuclear proteins must occur during the process of spermatogenesis, different organisms exhibit various patterns of sperm-specific protein mediating differential binding during the process. Sperm-specific variants of both H1 and H2B histones are observed in sea urchins, while the only variant observed in sea stars during spermatogenesis is SpH1. Sequencing of the N-terminus of SpH1 from A. vulgaris revealed a repeating tetrapeptide in residues 3-6 and 8-11 (Ser-Pro-Arg-Lys and Ser-Pro-Lys-Lys, respectively), homologous to repeats in the N-termini of sperm-specific H1s from sea urchins. Primary structure within critical, variable regions of molecules responsible for nonspecific DNA binding appear conserved in many organisms. The occurrence of repeating tetrapeptides in SpH1 and other DNA binding proteins suggests that such domains may function similarly in various chromatins undergoing regulated or reversible condensation.

  6. Psychiatric Morbidity and Social Capital in Rural Communities of the Greek North Aegean Islands

    ERIC Educational Resources Information Center

    Tseloni, Andromachi; Zissi, Anastasia; Skapinakis, Petros

    2010-01-01

    Which facets of social capital affect mental health in rural settings? This study explores the association between different aspects of social capital and psychiatric morbidity in rural communities of the Greek North Aegean islands. A large number of individual and community characteristics that may influence psychiatric morbidity are concurrently…

  7. Modelling the 2013 North Aegean (Greece) seismic sequence: geometrical and frictional constraints, and aftershock probabilities

    NASA Astrophysics Data System (ADS)

    Karakostas, Vassilis; Papadimitriou, Eleftheria; Gospodinov, Dragomir

    2014-04-01

    The 2013 January 8 Mw 5.8 North Aegean earthquake sequence took place on one of the ENE-WSW trending parallel dextral strike slip fault branches in this area, in the continuation of 1968 large (M = 7.5) rupture. The source mechanism of the main event indicates predominantly strike slip faulting in agreement with what is expected from regional seismotectonics. It was the largest event to have occurred in the area since the establishment of the Hellenic Unified Seismological Network (HUSN), with an adequate number of stations in close distances and full azimuthal coverage, thus providing the chance of an exhaustive analysis of its aftershock sequence. The main shock was followed by a handful of aftershocks with M ≥ 4.0 and tens with M ≥ 3.0. Relocation was performed by using the recordings from HUSN and a proper crustal model for the area, along with time corrections in each station relative to the model used. Investigation of the spatial and temporal behaviour of seismicity revealed possible triggering of adjacent fault segments. Theoretical static stress changes from the main shock give a preliminary explanation for the aftershock distribution aside from the main rupture. The off-fault seismicity is perfectly explained if μ > 0.5 and B = 0.0, evidencing high fault friction. In an attempt to forecast occurrence probabilities of the strong events (Mw ≥ 5.0), estimations were performed following the Restricted Epidemic Type Aftershock Sequence (RETAS) model. The identified best-fitting MOF model was used to execute 1-d forecasts for such aftershocks and follow the probability evolution in time during the sequence. Forecasting was also implemented on the base of a temporal model of aftershock occurrence, different from the modified Omori formula (the ETAS model), which resulted in probability gain (though small) in strong aftershock forecasting for the beginning of the sequence.

  8. The fast expansion of Pyropia aquaculture in ;Sansha; regions should be mainly responsible for the Ulva blooms in Yellow Sea

    NASA Astrophysics Data System (ADS)

    Zhang, Jianheng; Zhao, Peng; Huo, Yuanzi; Yu, Kefeng; He, Peimin

    2017-04-01

    Massive Ulva blooms became an environmental disaster in the Yellow Sea from 2007 to 2015. In this study, field shipboard observations indicated that Ulva blooms originated in Pyropia aquaculture area, and the morphology of initial floating Ulva seaweed have the structure of rhizoid, which is similar with the attached Ulva on the Pyropia rafts. The spatial distribution of Ulva microscopic propagules in the southern Yellow Sea also supported that the blooms originated in the Pyropia aquaculture area. Besides, numerical model was used in this study, showing the origin of macroalgal blooms was traced to ;Sansha; regions which accounted for almost 70% of the total Pyropia aquaculture area. We conclude that the significant biomass (4252 tons) of Ulva species on the Pyropia rafts during the harvesting season in ;Sansha; regions played an important role in the early rapid development of blooms in the Yellow Sea.

  9. On the Role of Arctic Sea Ice Deformations: An Evaluation of the Regional Arctic System Model Results with Observations.

    NASA Astrophysics Data System (ADS)

    Osinski, Robert; Maslowski, Wieslaw; Roberts, Andrew

    2016-04-01

    The atmosphere - sea ice - ocean fluxes and their contribution to rapid changes in the Arctic system are not well understood and generally are not resolved by global climate models (GCMs). While many significant model refinements have been made in the recent past, including the representation of sea ice rheology, surface albedo and ice-albedo feedback, other processes such as sea ice deformations, still require further studies and model advancements. Of particular potential interest here are linear kinematic features (LKFs), which control winter air-sea heat exchange and affect buoyancy forces in the ocean. Their importance in Arctic climate change, especially under an increasing first-year ice cover, is yet to be determined and their simulation requires representation of processes currently at sub-grid scale of most GCMs. To address some of the GCM limitations and to better understand the role of LKFs in air-sea exchange we use the Regional Arctic System Model (RASM), which allows high spatio-temporal resolution and regional focus on the Arctic. RASM is a fully coupled regional climate model, developed to study dynamic and thermodynamic processes and their coupling across the atmosphere-sea ice-ocean interface. It consists of the Weather Research and Forecasting (WRF) atmospheric model, the Parallel Ocean Program (POP), the Community Ice Model (CICE) and the Variable Infiltration Capacity (VIC) land hydrology model. The sea ice component has been upgraded to the Los Alamos Community Ice Model version 5.1 (CICE5.1), which allows either Elastic-Viscous-Plastic (EVP) or a new anisotropic (EPA) rheology. RASM's domain is pan-Arctic, with the ocean and sea ice components configured at an eddy-permitting horizontal resolution of 1/12-degree as well as 1/48-degree, for limited simulations. The atmosphere and land model components are configured at 50-km grids. All the components are coupled at a 20-minute time step. Results from multiple RASM simulations are analyzed and

  10. Hydro-engineering and environmental problems in Poti Black Sea region and ways of their solution

    NASA Astrophysics Data System (ADS)

    Saghinadze, Ivane; Pkhakadze, Manana; Kodua, Manoni; Gagoshidze, Shalva

    2016-04-01

    (The article was published with support of the Shota Rustaveli National Science Foundation) Work is dedicated to the development of hydro-engineering and environmental protection measures in the Black Sea regions, the main Georgian port of Poti at the mouth of the Rioni, which will minimize the region geomorphological changes caused by the influence of natural and anthropogenic factors, and will over a long period protect coastal areas of these regions from washouts and large scale silting processes. The research objects are: 1. Poti seashore, which has retreated for hundreds of meters, promoted with the existence of underwater canyon along the southern pier of the port; 2. The Rioni river watershed dam, the tail race of which in time was subjected to destruction and substantial washout. Currently the stability of the dam is endangered; 3. "City Canal" - the Rioni river old bed, which is greatly silted up and is virtually unable to perform its function - to feed Poti seashore with solid matter. The work for the hydrodynamics solutions using high-precision mathematical methods. In particular, for the establishment of coastal longshore migrations of sediment and deformations of the coastal zone is used finite element method, Crank-Nicolson scheme and method of upper relaxation in the calculation of wave propagation in the estuarine areas of the Rioni River uses direct and asymptotic (particularly WKB) Methods of mathematical analysis. The results obtained using these models will be put as a base of development of such engineering measures and design proposals which: a) will provide sustained increase of Poti coastal line on the basis of working out of exploitation regimes of the Rioni watershed hydro complex and as a result of performing additional engineering measures in "City Canal"; b) will thoroughly protect the Rioni watershed hydro complex dam tail-water from destruction and washouts. The packets of mathematical programs and analytical methods of calculation

  11. The organic sea surface microlayer in the upwelling region off Peru and implications for air-sea exchange processes

    NASA Astrophysics Data System (ADS)

    Engel, A.; Galgani, L.

    2015-07-01

    The sea surface microlayer (SML) is at the very surface of the ocean, linking the hydrosphere with the atmosphere, and central to a range of global biogeochemical and climate-related processes. The presence and enrichment of organic compounds in the SML have been suggested to influence air-sea gas exchange processes as well as the emission of primary organic aerosols. Among these organic compounds, primarily of plankton origin, are dissolved exopolymers, specifically polysaccharides and proteins, and gel particles, such as Transparent Exopolymer Particles (TEP) and Coomassie Stainable Particles (CSP). These organic substances often accumulate in the surface ocean when plankton productivity is high. Here, we report results obtained in December 2012 during the SOPRAN Meteor 91 cruise to the highly productive, coastal upwelling regime off Peru. Samples were collected from the SML and from ~ 20 cm below, and were analyzed for polysaccharidic and proteinaceous compounds, gel particles, total and dissolved organic carbon, bacterial and phytoplankton abundance. Our study provides insight to the physical and biological control of organic matter enrichment in the SML, and discusses the potential role of organic matter in the SML for air-sea exchange processes.

  12. Assigning king eiders to wintering regions in the Bering Sea using stable isotopes of feathers and claws

    USGS Publications Warehouse

    Oppel, S.; Powell, A.N.

    2008-01-01

    Identification of wintering regions for birds sampled during the breeding season is crucial to understanding how events outside the breeding season may affect populations. We assigned king eiders captured on breeding grounds in northern Alaska to 3 broad geographic wintering regions in the Bering Sea using stable carbon and nitrogen isotopes obtained from head feathers. Using a discriminant function analysis of feathers obtained from birds tracked with satellite transmitters, we estimated that 88 % of feathers were assigned to the region in which they were grown. We then assigned 84 birds of unknown origin to wintering regions based on their head feather isotope ratios, and tested the utility of claws for geographic assignment. Based on the feather results, we estimated that similar proportions of birds in our study area use each of the 3 wintering regions in the Bering Sea. These results are in close agreement with estimates from satellite telemetry and show the usefulness of stable isotope signatures of feathers in assigning marine birds to geographic regions. The use of claws is currently limited by incomplete understanding of claw growth rates. Data presented here will allow managers of eiders, other marine birds, and marine mammals to assign animals to regions in the Bering Sea based on stable isotope signatures of body tissues. ?? Inter-Research 2008.

  13. Coupled air-sea response to solar forcing in the Pacific region during northern winter

    NASA Astrophysics Data System (ADS)

    van Loon, Harry; Meehl, Gerald A.; Shea, Dennis J.

    2007-01-01

    Observations since the middle of the 19th century show that the decadal solar oscillation at its peaks strengthens the major convergence zones in the tropical Pacific (Intertropical Convergence Zone, ITCZ, and South Pacific Convergence Zone, SPCZ) during northern winter. Through an amplifying set of coupled feedbacks, a set of processes is described that link solar forcing and its response in the tropical Pacific with reductions in precipitation in the northwest United States. The process begins with an increase in solar forcing which results in a strengthening of the major convergence zones in the tropical Pacific. This then increases the precipitation in those regions and increases the southeast trade winds. Stronger trades increase the upwelling of colder water in the eastern equatorial Pacific and extend the cold tongue westward, thus reducing precipitation in the western Pacific. This redistribution of diabatic heating and associated convective heating anomalies thus produces anomalies in the tropical Hadley (north-south) and Walker (east-west) circulations. The former weakens as subsidence in equatorial latitudes is enhanced; the latter strengthens and extends westward. Additionally, the resulting anomalous Rossby wave response in the atmosphere, and consequent positive sea level pressure anomalies in the eastern region of the Aleutian low in the North Pacific that extends to western North America, is associated with reductions of precipitation in the northwest United States. The response of the climate system to solar forcing is manifested as a strengthening of the climatological precipitation maxima in the tropics.

  14. Shipboard Investigation of Air-sea Interaction and Cloud Processes in the VOCALS Stratocumulus Region

    NASA Astrophysics Data System (ADS)

    Fairall, C.; Kollias, P.; Zuidema, P.

    2005-12-01

    NOAA ETL, University of Miami, and Brookhaven National Laboratory have cooperated with the Woods Hole Oceanographic Institution (WHOI) for two research cruises to the stratocumulus region of Peru/Chile as part of NOAA's PACS/EPIC program. Ship-based measurements have taken in October of 2001, November 2003, and December 2004 at the WHOI ocean reference buoy at 20 S 85 W during the annual cruise to service the buoy. The goal of this work is to improve understanding of coupled air-sea processes in subtropical stratocumulus regions and to gather statistics on flux, boundary layer, and cloud properties to promote the evaluation of models and satellite data products. Specific scientific objectives involve improved bulk cloud-radiative parameterizations, methods for retrieving cloud microphysical properties, and investigation of the relative roles of cloud-top entrainment and drizzle production on the dynamics of stratocumulus. The measurements provide a more detailed context for measurements made on the WHOI buoy over the annual cycle. This will be achieved through: *Comprehensive characterization of clouds, surface fluxes, and PBL profiles using a variety of in situ and remote sensing systems *Evaluation of various bulk models of stratocumulus cloud radiative transfer properties using resulting cloud microphysics (integrated liquid water, drop size and number concentration) determined with ship-board remote sensors In this paper we will present the results from the three cruises emphasizing then diurnal cycle of cloud properties and comparing the seasonal differences.

  15. Fatal poisoning of chilhood in the Eastern Black Sea region of Turkey (2009-2013).

    PubMed

    Karadeniz, Hulya; Birincioglu, Ismail; Turna, Ozgur; Ketenci, Huseyin Cetin; Beyhun, Nazım Ercument

    2015-08-01

    Poisoning is a major problem worldwide among children. Nonetheless, the offending agent, the associated morbidity and mortality vary from place to place and show changes over a period of time. The aim of this study was to investigate the medico-legal paediatric autopsies of childhood poisonings in the Eastern Black Sea Region of Turkey. Reports of autopsies performed between 2009 and 2013 in the Morgue Department of the Council of Forensic Medicine. All medico-legal paediatric autopsies in Trabzon (n:1049) were retrospectively examined. The study comprised an investigation into 62 deaths from poisoning in children aged 0-18 years. The parameters of age, sex, toxic substance category and origin were evaluated. Poisoning accounted for 5.9% of the deaths of children aged 0-18 years. Of the 62 cases, 32 (51.6%) were male and 30 (48.4%) were female, giving a female to male ratio of 1/1.1. The primary causes of fatal poisoning in children were carbon monoxide (64.5%, n = 40), followed by drugs (16.1%, n = 10), insecticides (9.7%, n = 6), mushrooms (6.5%, n = 4), and snake venom (3.2%, n = 2). The results of this study implicated carbon monoxide poisoning as a serious risk factor for mortality in our region. Childhood poisoning may be prevented by public education and simple precautions in general.

  16. A wrench and inversion model for structures in the Timor Sea region, northwest Austrialia

    SciTech Connect

    Nelson, A.W.

    1996-01-01

    A structural model is developed for part of the Timor Sea region, northwest Australia, involving multiple strike-slip episodes, and significant changes in the regional or local stress regimes. It is interpreted that both normal and reverse faults have existed since at least the Permian, and have changed their sense of movement in response to changing stress fields, with latest changes occurring as a result of Tertiary collision of the Australian and Eurasian Plates. Both 2-D and 3-D seismic data sets are used to demonstrate development of conventional simple strike-slip models into complex multi-episode models incorporating through-going and abandoned faults. After only three episodes of fault movement, one of which involves inversion, the fault linkages and structural history can become very difficult to unravel. The Jabiru Oil Field is shown to have developed at the intersection of orthogonal faults, with resultant restraining fault bend geometry. Failure to identify a large part of the field for several years after discovery may be attributed to misinterpretation of reversal of fault throw with depth (resulting from inversion), and to lack of appreciation of the significance of abandoned faults. Factors including fault abandonment, fault dips steepening with depth (including sideways concave faults), fault inversion, and trap seal development on inverted and abandoned faults may have a significant influence on the way petroleum traps are mapped and the trapping capacity of seals.

  17. A wrench and inversion model for structures in the Timor Sea region, northwest Austrialia

    SciTech Connect

    Nelson, A.W.

    1996-12-31

    A structural model is developed for part of the Timor Sea region, northwest Australia, involving multiple strike-slip episodes, and significant changes in the regional or local stress regimes. It is interpreted that both normal and reverse faults have existed since at least the Permian, and have changed their sense of movement in response to changing stress fields, with latest changes occurring as a result of Tertiary collision of the Australian and Eurasian Plates. Both 2-D and 3-D seismic data sets are used to demonstrate development of conventional simple strike-slip models into complex multi-episode models incorporating through-going and abandoned faults. After only three episodes of fault movement, one of which involves inversion, the fault linkages and structural history can become very difficult to unravel. The Jabiru Oil Field is shown to have developed at the intersection of orthogonal faults, with resultant restraining fault bend geometry. Failure to identify a large part of the field for several years after discovery may be attributed to misinterpretation of reversal of fault throw with depth (resulting from inversion), and to lack of appreciation of the significance of abandoned faults. Factors including fault abandonment, fault dips steepening with depth (including sideways concave faults), fault inversion, and trap seal development on inverted and abandoned faults may have a significant influence on the way petroleum traps are mapped and the trapping capacity of seals.

  18. Spatial Distribution of Carbonaceous Aerosol in the Southeastern Baltic Sea Region (Event of Grass Fires)

    NASA Astrophysics Data System (ADS)

    Dudoitis, Vadimas; Byčenkienė, Steigvilė; Plauškaitė, Kristina; Bozzetti, Carlo; Fröhlich, Roman; Mordas, Genrik; Ulevičius, Vidmantas

    2016-06-01

    The aerosol chemical composition in air masses affected by large vegetation fires transported from the Kaliningrad region (Russia) and southeast regions (Belarus and Ukraine) during early spring (March 2014) was characterized at the remote background site of Preila, Lithuania. In this study, the chemical composition of the particulate matter was studied by high temporal resolution instruments, including an Aerosol Chemical Speciation Monitor (ACSM) and a seven-wavelength aethalo-meter. Air masses were transported from twenty to several hundred kilometres, arriving at the measurement station after approximately half a day of transport. The concentration-weighted trajectory analysis suggests that organic aerosol particles are mainly transported over the Baltic Sea and the continent (southeast of Belarus). Results show that a significant fraction of the vegetation burning organic aerosol is transformed into oxidised forms in less than a half-day. Biomass burning aerosol (BBOA) was quantified from the ACSM data using a positive matrix factorization (PMF) analysis, while its spatial distribution was evaluated using air mass clustering approach.

  19. Unravelling environmental conditions during the Holocene in the Dead Sea region using multiple archives

    NASA Astrophysics Data System (ADS)

    Rambeau, Claire; van Leeuwen, Jacqueline; van der Knaap, Pim; Gobet, Erika

    2016-04-01

    For the most arid parts of the Southern Levant (roughly corresponding to modern Jordan, Israel and Palestine), environmental reconstructions are impeded by the limited number of archives, and the frequent contradictions between individual palaeoenvironmental records. The Southern Levant is characterised by steep climate gradients; local conditions presently range from arid to dry Mediterranean, with limits that may have fluctuated during the Holocene. This further complicates the determination of site-specific past environmental conditions. Understanding past climate and environmental evolution through time, at a local level, is however crucial to compare these with societal evolution during the Holocene, which features major cultural developments such as cereal cultivation, animal domestication, water management, as well as times of preferential settlement growth or site abandonment. This contribution proposes to examine the different archives available for the Dead Sea region, paying special attention to the most recent pollen data obtained from the area. It will particularly critically compare local to regional-scale information, and try to decipher the main evolutions of environmental conditions during the Holocene in arid and semi-arid Southern Levant.

  20. Supporting Coastal Management Decisions in the Face of Sea-Level Rise: Case Study for the Chesapeake Bay Region

    NASA Astrophysics Data System (ADS)

    Staudt, A. C.; Glick, P.; Clough, J. S.; Nunley, B.

    2008-12-01

    Sea-level rise needs to be a major consideration in regional coastal management and ecological restoration plans. The National Wildlife Federation has initiated a multi-pronged strategy for assisting decision makers at government agencies that manage near-shore ecosystems in several vulnerable coastal regions. Results from our work in the Chesapeake Bay region will be presented. This strategy involves: (1) Detailed modeling of how coastal habitats will migrate in response to a range of sea-level rise scenarios. For this work, we used the Sea Level Affecting Marshes Model (SLAMM), which simulates the dominant processes involved in wetland conversions and shoreline modifications during long-term sea-level rise and takes into consideration localized changes in land elevation due to geological and ecological factors. These model results provide specific information about the locations that are likely to experience shifts in coastal marshes, swamps, beaches, and other habitats due to sea-level rise at a scale that is relevant to regional decision making. (2) Extensive literature review and analysis of habitat, fish, and wildlife impacts potentially resulting from expected sea-level rise and other local climate changes. Synthesizing the available research is an important service for natural resource agencies that are only beginning to consider climate impacts on ecosystems and natural resources. (3) Analysis of government programs and policies relevant to coastal management and identification of opportunities to revise these policies in light of projected climate changes. An important aspect of this analysis is meeting with key decision makers at relevant state fish and wildlife agencies to better understand the factors that affect their abilities to effect policy changes. (4) Proactive campaign to share our results with diverse audiences. We have developed different research products, ranging from a technical report of the modeling results to short report briefs, to

  1. Storm surges in the Mediterranean Sea: Variability and trends under future climatic conditions

    NASA Astrophysics Data System (ADS)

    Androulidakis, Yannis S.; Kombiadou, Katerina D.; Makris, Christos V.; Baltikas, Vassilis N.; Krestenitis, Yannis N.

    2015-09-01

    The trends of storm surge extremes in the Mediterranean Sea for a period of 150 years (1951-2100) are explored, using a high-resolution storm surge model. Numerical simulations are forced by the output of regional climate simulations with RegCM3, which uses IPCC's historical data on greenhouse gasses emissions for the (past) period 1951-2000, and IPCC's A1B climate scenario for the (future) period 2001-2100. Comparisons between observations and modeling results show good agreement and confirm the ability of our model to estimate the response of the sea surface to future climatic conditions. We investigate the future trends, the variability and frequency of local extremes and the main forcing mechanisms that can induce strong surges in the Mediterranean region. Our results support that there is a general decreasing trend in storminess under the considered climate scenario, mostly related to the frequency of local peaks and the duration and spatial coverage of the storm surges. The northward shift in the location of storm tracks is a possible reason for this storminess attenuation, especially over areas where the main driving factor of extreme events is the inverted barometer effect. However, the magnitudes of sea surface elevation extremes may increase in several Mediterranean sub-regions, i.e., Southern Adriatic, Balearic and Tyrrhenian Seas, during the 21st century. There are clear distinctions in the contributions of winds and pressure fields to the sea level height for various regions of the Mediterranean Sea, as well as on the seasonal variability of extreme values; the Aegean and Adriatic Seas are characteristic examples, where high surges are predicted to be mainly induced by low pressure systems and favorable winds, respectively.

  2. Measurements of regional-scale aerosol impacts on cloud microphysics over the East China Sea: Possible influences of warm sea surface temperature over the Kuroshio ocean current

    NASA Astrophysics Data System (ADS)

    Koike, M.; Takegawa, N.; Moteki, N.; Kondo, Y.; Nakamura, H.; Kita, K.; Matsui, H.; Oshima, N.; Kajino, M.; Nakajima, T. Y.

    2012-09-01

    Cloud microphysical properties and aerosol concentrations were measured aboard an aircraft over the East China Sea and Yellow Sea in April 2009 during the Aerosol Radiative Forcing in East Asia (A-FORCE) experiment. We sampled stratocumulus and shallow cumulus clouds over the ocean in 9 cases during 7 flights 500-900 km off the east coast of Mainland China. In this study we report aerosol impacts on cloud microphysical properties by focusing on regional characteristics of two key parameters, namely updraft velocity and aerosol size distribution. First, we show that the cloud droplet number concentration (highest 5%, Nc_max) correlates well with the accumulation-mode aerosol number concentration (Na) below the clouds. We then show that Nc_maxcorrelates partly with near-surface stratification evaluated as the difference between the sea surface temperature (SST) and 950-hPa temperature (SST - T950). Cold air advection from China to the East China Sea was found to bring not only a large number of aerosols but also a dry and cold air mass that destabilized the atmospheric boundary layer, especially over the warm Kuroshio ocean current. Over this high-SST region, greater updraft velocities and hence greater Nc_maxlikely resulted. We hypothesize that the low-level static stability determined by SST and regional-scale airflow modulates both the cloud microphysics (aerosol impact on clouds) and macro-structure of clouds (cloud base and top altitudes, hence cloud liquid water path). Second, we show that not only higher aerosol loading in terms of total aerosol number concentration (NCN, D > 10 nm) but also larger aerosol mode diameters likely contributed to high Ncduring A-FORCE. The mean Nc of 650 ± 240 cm-3was more than a factor of 2 larger than the global average for clouds influenced by continental sources. A crude estimate of the aerosol-induced cloud albedo radiative forcing is also given.

  3. The effect of spatial averaging and glacier melt on detecting a forced signal in regional sea level

    NASA Astrophysics Data System (ADS)

    Richter, Kristin; Marzeion, Ben; Riva, Riccardo

    2017-03-01

    We investigate the spatial scales that are necessary to detect an externally forced signal in regional sea level within a selected fixed time period. Detection on a regional scale is challenging due to the increasing magnitude of unforced variability in dynamic sea level on progressingly smaller spatial scales. Using unforced control simulations with no evolving forcing we quantify the magnitude of regional internal variability depending on the degree of spatial averaging. We test various averaging techniques such as zonal averaging and averaging grid points within selected radii. By comparing the results from the control simulations with historical and 21st-century simulations, the procedure allows to estimate to what degree the data has to be averaged spatially in order to detect a forced signal within certain periods (e.g. periods with good observational coverage). We find that zonal averaging over ocean basins is necessary to detect a forced signal in steric and dynamic sea level during the past 25 years, while a signal emerges in 63% of the ocean areas over the past 45 years when smoothing with a 2000 km filter or less is applied. We also demonstrate that the addition of the glacier contribution increases the signal-to-noise ratio of regional sea level changes, thus leading to an earlier emergence by 10–20 years away from the sources of the ice mass loss. With smoothing, this results in the detection of an external signal in 90% of the ocean areas over the past 45 years.

  4. An Institutional Case Study of Colleges and Universities Associated with Sea Grant in the Pacific Region of the United States

    ERIC Educational Resources Information Center

    Herrmann, Adelheid C.

    2013-01-01

    Purpose: The purpose of this study was to examine fishery degree programs at colleges and universities associated with the Sea Grant program in the Pacific region of the United States and to describe how each addresses protecting, rebuilding, and maintaining healthy oceans. Methodology: The study was a qualitative institutional case study that…

  5. 76 FR 30956 - Outer Continental Shelf, Alaska OCS Region, Chukchi Sea Planning Area, Oil and Gas Lease Sale 193

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-27

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE INTERIOR Bureau of Ocean Energy Management, Regulation and Enforcement Outer Continental Shelf, Alaska OCS Region, Chukchi Sea Planning Area, Oil and Gas Lease Sale 193 AGENCY: Bureau of Ocean Energy...

  6. 76 FR 53481 - Outer Continental Shelf, Alaska OCS Region, Chukchi Sea Planning Area, Oil and Gas Lease Sale 193

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-26

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE INTERIOR Bureau of Ocean Energy Management, Regulation and Enforcement Outer Continental Shelf, Alaska OCS Region... Continental Shelf (OCS) Oil and Gas Lease Sale 193, Chukchi Sea, Alaska (OCS EIS/EA BOEMRE 2011-041)....

  7. 75 FR 63504 - Outer Continental Shelf, Alaska OCS Region, Chukchi Sea Planning Area, Oil and Gas Lease Sale 193

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-15

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE INTERIOR Bureau of Ocean Energy Management, Regulation and Enforcement Outer Continental Shelf, Alaska OCS Region, Chukchi Sea Planning Area, Oil and Gas Lease Sale 193 AGENCY: Bureau of Ocean Energy...

  8. Geoacoustic models of the Donghae-to-Gangneung region in the Korean continental margin of the East Sea

    NASA Astrophysics Data System (ADS)

    Ryang, Woo Hun; Kim, Seong Pil; Hahn, Jooyoung

    2016-04-01

    Geoacoustic model is to provide a model of the real seafloor with measured, extrapolated, and predicted values of geoacoustic environmental parameters. It controls acoustic propagation in underwater acoustics. In the Korean continental margin of the East Sea, this study reconstructed geoacoustic models using geoacoustic and marine geologic data of the Donghae-to-Gangneung region (37.4° to 37.8° in latitude). The models were based on the data of the high-resolution subbottom and air-gun seismic profiles with sediment cores. The Donghae region comprised measured P-wave velocities and attenuations of the cores, whereas the Gangneung region comprised regression values using measured values of the adjacent areas. Geoacoustic data of the cores were extrapolated down to a depth of the geoacoustic models. For actual modeling, the P-wave speed of the models was compensated to in situ depth below the sea floor using the Hamilton method. These geoacoustic models of this region probably contribute for geoacoustic and underwater acoustic modelling reflecting vertical and lateral variability of acoustic properties in the Korean continental margin of the western East Sea. Keywords: geoacoustic model, environmental parameter, East Sea, continental margin Acknowledgements: This research was supported by the research grants from the Agency of Defense Development (UD140003DD and UE140033DD).

  9. Greenland coastal air temperatures linked to Baffin Bay and Greenland Sea ice conditions during autumn through regional blocking patterns

    NASA Astrophysics Data System (ADS)

    Ballinger, Thomas J.; Hanna, Edward; Hall, Richard J.; Miller, Jeffrey; Ribergaard, Mads H.; Høyer, Jacob L.

    2017-03-01

    Variations in sea ice freeze onset and regional sea surface temperatures (SSTs) in Baffin Bay and Greenland Sea are linked to autumn surface air temperatures (SATs) around coastal Greenland through 500 hPa blocking patterns, 1979-2014. We find strong, statistically significant correlations between Baffin Bay freeze onset and SSTs and SATs across the western and southernmost coastal areas, while weaker and fewer significant correlations are found between eastern SATs, SSTs, and freeze periods observed in the neighboring Greenland Sea. Autumn Greenland Blocking Index values and the incidence of meridional circulation patterns have increased over the modern sea ice monitoring era. Increased anticyclonic blocking patterns promote poleward transport of warm air from lower latitudes and local warm air advection onshore from ocean-atmosphere sensible heat exchange through ice-free or thin ice-covered seas bordering the coastal stations. Temperature composites by years of extreme late freeze conditions, occurring since 2006 in Baffin Bay, reveal positive monthly SAT departures that often exceed 1 standard deviation from the 1981-2010 climate normal over coastal areas that exhibit a similar spatial pattern as the peak correlations.

  10. Carbonate assimilation during magma evolution at Nisyros (Greece), South Aegean Arc: Evidence from clinopyroxenite xenoliths

    NASA Astrophysics Data System (ADS)

    Spandler, Carl; Martin, Lukas H. J.; Pettke, Thomas

    2012-08-01

    To contribute to the understanding of magma evolution in arc settings we investigate the oldest volcanic unit (Kanafià Synthem) of Nisyros volcano, located in the eastern Aegean Sea (Greece). The unit consists of porphyritic pillow lavas of basaltic andesite composition with trace element signatures that are characteristic of island-arc magmas. Two lava types are distinguished on the basis of geochemistry and the presence or absence of xenoliths, with the xenolith-bearing lavas having distinctly elevated Sr, MREE/HREE and MgO/Fe2O3 compared to the xenolith-free lavas. Xenoliths include relatively rare quartzo-feldspathic fragments that represent continental-type material, and coarse clinopyroxenite xenoliths that consist largely of aluminous and calcic clinopyroxene, and accessory aluminous spinel. Anorthite-diopside reaction selvages preserved around the clinopyroxenite xenoliths demonstrate disequilibrium between the xenoliths and the host magma. The xenolith clinopyroxene is distinctly enriched in most lithophile trace elements compared to clinopyroxene phenocrysts in the host magmas. A notable exception is the Sr concentration, which is similar in both clinopyroxene types. The high Al and low Na contents of the clinopyroxenites preclude a cumulate, deep metamorphic, or mantle origin for these xenoliths. Instead, their composition and mineralogy are diagnostic of skarn rocks formed by magma-carbonate interaction in the mid/upper crust. The Kanafià lavas are interpreted to have undergone crystal fractionation, magma mixing/mingling and crustal assimilation while resident in the upper crust. We show that magma-carbonate reaction and associated skarn formation does not necessarily result in easily recognised modification of the melt composition, with the exception of increasing Sr contents. Carbonate assimilation also releases significant CO2, which will likely form a free vapour phase due to the low CO2 solubility of arc magmas. In the broader context, we stress

  11. Comparison of glacial isostasy contribution to the sea level changes during the Holocene in West and East Antarctic regions.

    NASA Astrophysics Data System (ADS)

    Poleshchuk, Ksenia; Verkulich, Sergey; Pushina, Zina

    2016-04-01

    Antarctica as geographically completed and tectonically compound continent is an interesting object for study of glacial isostatic adjustment (GIA) and sea level changes in the Holocene. The analysis of relative sea level curves is one of the most indicative approaches for glacio-isostasy estimation. The present study focuses on two different regions of Antarctic margin which sea-level changes are well researched. We compare our relative sea-level curves for Bunger Oasis (East Antarctica) and King George Island (West Antarctica) that were obtained from new geomorphological, paleogeographical and micropaleontological data. The results showed notable difference: the maximum relative water altitude had occurred between 8 000 - 6 000 yr BP and had reached 12 m a. s. l. in the Bunger Oasis and 18-20 m a. s. l. in King George Island. Furthermore, the research of other Antarctic regions revealed significant differences in sea-level altitudes. Following analysis of constructed curves and computative GIA models allow us to estimate the possible extent of glacial isostatic adjustment. Besides, this observation has indicated the importance of deglaciation rates and local tectonic features. The reported study was funded by RFBR according to the research project No. 16-35-00346 mol_a.

  12. A probabilistic approach to 21st century regional sea-level projections using RCP and High-end scenarios

    NASA Astrophysics Data System (ADS)

    Jackson, Luke P.; Jevrejeva, Svetlana

    2016-11-01

    Sea-level change is an integrated climate system response due to changes in radiative forcing, anthropogenic land-water use and land-motion. Projecting sea-level at a global and regional scale requires a subset of projections - one for each sea-level component given a particular climate-change scenario. We construct relative sea-level projections through the 21st century for RCP 4.5, RCP 8.5 and High-end (RCP 8.5 with increased ice-sheet contribution) scenarios by aggregating spatial projections of individual sea-level components in a probabilistic manner. Most of the global oceans adhere to the projected global average sea level change within 5 cm throughout the century for all scenarios; however coastal regions experience localised effects due to the non-uniform spatial patterns of individual components. This can result in local projections that are 10‧s of centimetres different from the global average by 2100. Early in the century, RSL projections are consistent across all scenarios, however from the middle of the century the patterns of RSL for RCP scenarios deviate from the High-end where the contribution from Antarctica dominates. Similarly, the uncertainty in projected sea-level is dominated by an uncertain Antarctic fate. We also explore the effect upon projections of, treating CMIP5 model ensembles as normally distributed when they might not be, correcting CMIP5 model output for internal variability using different polynomials and using different unloading patterns of ice for the Greenland and Antarctic ice sheets.

  13. Genomic characterization of Sinorhizobium meliloti AK21, a wild isolate from the Aral Sea Region.

    PubMed

    Molina-Sánchez, María Dolores; López-Contreras, José Antonio; Toro, Nicolás; Fernández-López, Manuel

    2015-01-01

    The symbiotic, nitrogen-fixing bacterium Sinorhizobium meliloti has been widely studied due to its ability to improve crop yields through direct interactions with leguminous plants. S. meliloti AK21 is a wild type strain that forms nodules on Medicago plants in saline and drought conditions in the Aral Sea Region. The aim of this work was to establish the genetic similarities and differences between S. meliloti AK21 and the reference strain S. meliloti 1021. Comparative genome hybridization with the model reference strain S. meliloti 1021 yielded 365 variable genes, grouped into 11 regions in the three main replicons in S. meliloti AK21. The most extensive regions of variability were found in the symbiotic plasmid pSymA, which also contained the largest number of orthologous and polymorphic sequences identified by suppression subtractive hybridization. This procedure identified a large number of divergent sequences and others without homology in the databases, the further investigation of which could provide new insight into the alternative metabolic pathways present in S. meliloti AK21. We identified a plasmid replication module from the repABC replicon family, together with plasmid mobilization-related genes (traG and a VirB9-like protein), which suggest that this indigenous isolate harbors an accessory plasmid. Furthermore, the transcriptomic profiles reflected differences in gene content and regulation between S. meliloti AK21 and S. meliloti 1021 (ExpR and PhoB regulons), but provided evidence for an as yet unknown, alternative mechanism involving activation of the cbb3 terminal oxidase. Finally, phenotypic microarrays characterization revealed a greater versatility of substrate use and chemical degradation than for S. meliloti 1021.

  14. Localised and distributed deformation in the lithosphere: Modelling the Dead Sea region in 3 dimensions

    NASA Astrophysics Data System (ADS)

    Devès, Maud; King, Geoffrey C. P.; Klinger, Yann; Agnon, Amotz

    2011-08-01

    The Earth's lithosphere behaves as a strain softening elasto-plastic material. In the laboratory, such materials are known to deform in a brittle or a ductile manner depending on the applied geometric boundary conditions. In the lithosphere however, the importance of boundary conditions in controlling the deformation style has been largely ignored. Under general boundary conditions, both laboratory and field scale observations show that only part of the deformation can localise on through going faults while the rest must remain distributed in 'process zones' where spatially varying shear directions inhibit localisation. Conventional modelling methods (finite difference, finite or discrete elements) use rheologies deduced from laboratory experiments that are not constrained as a function of the geometry of the applied boundary conditions. In this paper, we propose an alternative modelling method that is based on the use of an appropriate distribution of dislocation sources to create the deformation field. This approach, because it does not rely on integrating differential equations from more or less well-constrained boundary conditions, does not require making assumptions on the parameters controlling the level and distribution of stresses within the lithosphere. It only supposes that strain accumulates linearly away from the dislocation singularities satisfying the compatibility equations. We verify that this model explains important and hitherto unexplained features of the topography of the Dead Sea region. Following the idea that strain can only localise under specific conditions as inferred from laboratory and field scale observations, we use our model of deformation to predict where deformation can localise and where it has to remain distributed. We find that ~ 65% of the deformation in the Dead Sea region can localise on kinematically stable through-going strike-slip faults while the remaining ~ 35% has to remain distributed. Observations suggest that

  15. Localised and distributed deformation in the lithosphere: Modelling the Dead Sea region in 3 dimensions

    NASA Astrophysics Data System (ADS)

    Devès, M.; King, G. C. P.; Klinger, Y.; Agnon, A.

    2012-04-01

    The Earth's lithosphere behaves as a strain softening elasto-plastic material. In the laboratory, such materials are known to deform in a brittle or a ductile manner depending on the applied geometric boundary conditions. In the lithosphere however, the importance of boundary conditions in controlling the deformation style has been largely ignored. Under general boundary conditions, both laboratory and field scale observations show that only part of the deformation can localise on through going faults while the rest must remain distributed in 'process zones' where spatially varying shear directions inhibit localisation. Conventional modelling methods (finite difference, finite or discrete elements) use rheologies deduced from laboratory experiments that are not constrained as a function of the geometry of the applied boundary conditions. In this paper, we propose an alternative modelling method that is based on the use of an appropriate distribution of dislocation sources to create the deformation field. This approach, because it does not rely on integrating differential equations from more or less well-constrained boundary conditions, does not require making assumptions on the parameters controlling the level and distribution of stresses within the lithosphere. It only supposes that strain accumulates linearly away from the dislocation singularities satisfying the compatibility equations. We verify that thismodel explains important and hitherto unexplained features of the topography of the Dead Sea region. Following the idea that strain can only localise under specific conditions as inferred from laboratory and field scale observations, we use our model of deformation to predict where deformation can localise and where it has to remain distributed. We find that ~65% of the deformation in the Dead Sea region can localise on kinematically stable through-going strike-slip faults while the remaining ~35% has to remain distributed. Observations suggest that distributed

  16. Partitioning Regional Sea Level in the Bay of Bengal from a Global Grace and Jason-1/-2 Joint Inversion

    NASA Astrophysics Data System (ADS)

    Kusche, J.; Uebbing, B.; Rietbroek, R.

    2014-12-01

    In Bangladesh, large areas are located just above sea level. Present-day sea level rise in combination with land subsidence, poses a major threat to the coastal regions, home of about 30 million people. Consequently, monitoring of sea level and knowledge of all recurrent effects are crucial for coastal protection. As part of the Belmont-project "Bangladesh Delta: Assessment of the Causes of Sea-level Rise Hazards and Integrated Development of Predictive Modeling Towards Mitigation and Adaptation" (BAND-AID) a global inverse method is employed to estimate the different contributors to sea level, such as melting of glaciers and ice-sheets, hydrology, glacial isostatic adjustment, as well as shallow and deep steric effects from Jason-1/2 altimetry and GRACE data. In the global inverse method, spatial patterns (fingerprints) are computed a-priori for each of the contributing process, applying the sea level equation for mass fingerprints, and empirically (PCA) for steric fingerprints from ARGO data. Temporal GRACE gravity data and along-track Jason-1/ -2 altimetry is then combined to estimate the temporal evolution of these patterns, which allows the partitioning of altimetric sea level into individual sources. This method largely mitigates truncation and leakage problems associated with GRACE resolution. Globally, our estimates are close to others, although they point at a somewhat larger deep steric effect. In this work we provide preliminary results for the Bay of Bengal / Bangladesh region by confronting global inversion with local measurements. Estimated sea level trends are compared to trends from tide gauges and differences are interpreted in terms of unmodeled regional effects, such as land subsidence. Initial results provide an indication on the magnitude of the contributions from the different sources at the coast of Bangladesh / in the Bay of Bengal; e.g. the contribution from the Greenland ice-sheets between 2003 and 2011 (0.69 mm/a) is significantly larger

  17. Anelastic attenuation structure of the southern Aegean subduction area

    NASA Astrophysics Data System (ADS)

    Ventouzi, Chrisanthi; Papazachos, Constantinos; Papaioannou, Christos; Hatzidimitriou, Panagiotis

    2014-05-01

    The study of the anelastic attenuation structure plays a very important role for seismic wave propagation and provides not only valuable constraints for the Earth's interior (temperature, relative viscosity, slab dehydration and melt transport) but also significant information for the simulation of strong ground motions. In order to investigate the attenuation structure of the broader Southern Aegean subduction area, acceleration spectra of intermediate depth earthquakes produced from data provided by two local networks which operated in the area were used. More specifically, we employed data from approximately 400 intermediate-depth earthquakes, as these were recorded from the EGELADOS seismic monitoring project which consisted of 65 land stations and 24 OBS recorders and operated during 2005-2007, as well as data from the earlier installed CYCNET local network, which operated during 2002-2005. A frequency-independent path attenuation operator t* was computed for both P and S arrivals for each waveform, using amplitude spectra generated by the recorded data of the aforementioned networks. Initially, estimated P and S traveltimes were examined and modeled as a function of epicentral distance for different groups of focal depths, using data from the CYCNET network in order to obtain the expected arrival information when original arrival times were not available. Two approaches to assess the spectral-decay were adopted for t* determination. Initially, an automated approach was used, where t* was automatically calculated from the slope of the acceleration spectrum, assuming an ω2 source model for frequencies above the corner frequency, fc. Estimation of t* was performed in the frequency band of 0.2 to 25 Hz, using only spectra with a signal-to-noise ratio larger than 3 for a frequency range of at least 4Hz for P-waves and 1Hz for S-waves, respectively. In the second approach, the selection of the linearly-decaying part of the spectra where t* was calculated, was

  18. Sea-floor environments within Long Island Sound: a regional overview

    USGS Publications Warehouse

    Knebel, Harley J.; Poppe, Lawrence J.

    2000-01-01

    Modern sea-floor sedimentary environments within the glaciated, topographically complex Long Island Sound estuary have been interpreted and mapped from an extensive collection of sidescan sonographs, bottom samples, and video-camera observations together with supplemental bathymetric, marine-geologic, and bottom-current data. Four categories of environments are present that reflect the dominant long-term processes of erosion or nondeposition; coarsegrained bedload transport; sediment sorting and reworking; and fine-grained deposition. (1) Environments of erosion or nondeposition contain exposures of glacial drift, coarse lag deposits, and possibly bedrock and include sediments which range from boulder fields to gravelly coarse-to-medium sands. (2) Environments of coarse-grained bedload transport are mantled by sand ribbons and sand waves and contain mostly coarse-to-fine sands with only small amounts of mud. (3) Environments of sediment sorting and reworking comprise both uniform and heterogeneous sediment types and contain variable amounts of fine sand and mud. (4) Environments of fine-grained deposition are blanketed by muds and sandy muds. The patchy distribution of sedimentary environments within Long Island Sound reflects both regional and local changes in bottom processes. Regional changes are primarily the result of a strong, east-to-west decreasing gradient of bottom tidal-current speeds, coupled with the net (westward) estuarine bottom drift. The regional current regime has produced a westward succession of env