scholarly journals Speed structure of the mantle of the border of the Eastern European and West European platforms

2021 ◽  
Vol 43 (5) ◽  
pp. 181-192
Author(s):  
T. A. Tsvetkova ◽  
I. V. Bugaenko ◽  
L. N. Zaets
Keyword(s):  
Baltic Sea ◽  
Transition Zone ◽  
Upper Mantle ◽  
High Velocity ◽  
Oil And Gas ◽  
The Baltic Sea ◽  
Low Velocity ◽  
East European ◽  
The Baltic ◽  
West European

This work is devoted to studying the velocity structure of the mantle of the border area of the East European and West European platforms in the crust separated by the Teiserre-Tornquist zone. The mantle under the territory of Poland and Western Ukraine is being investigated. The work uses a three-dimensional P-velocity model of the mantle, constructed using the Taylor approximation method developed by V. S. Geyko. The method’s advantages are independent of the initial approximation (reference model) and the best approximation of nonlinearity. In this area, the exploration depth is 2500 km south of 50 °NL and 1700 km north of 50 °NL. A detailed analysis of horizontal sections of a 3D P-velocity model of the mantle up to a depth of 850 km with a step of 50 km has been carried out. The change in the spatial distribution of the zero seismic velocity boundary is analyzed throughout the depths. This boundary separates the high-velocity upper mantle of the East European Platform and the low-velocity upper mantle of the West European Platform. At the depths of the transition zone of the upper mantle, this boundary separates the low-velocity upper mantle of the East European platform and the high-velocity upper mantle of the West European platform (in this geosphere, a velocity inversion has occurred with respect to the upper mantle). In latitudinal sections, two inclined layers are distinguished. One of them is associated with the upper mantle under the DDV and reaches the mantle under the Carpathians, where it begins to plunge into the high-velocity transition zone of the upper mantle. The second layer is associated with the mantle under the northwestern end of the Baltic syneclise, which extends to the mantle under the Presudet monocline, where it also plunges into the high-velocity transition zone of the upper mantle. In longitudinal sections, inclined layers are distinguished, extending from the mantle under the South Scandinavian megablock of the Baltic Shield to the mantle under the Bohemian massif and the Carpathians, where they plunge into the high-velocity transition zone of the upper mantle. In the study area, three super-deep fluids were identified, characterized by increased stratification of the medium (alternation of higher and lower velocities). The first includes the well-known oil and gas fields of the Central European oil and gas basin (Pomorie and Presudet monocline (Poland)). The second is associated with oil and gas fields of the North Ciscarpathian oil and gas basin (southeastern Poland) and the Carpathian oil and gas basin (Western Ukraine). The extracted super-deep fluid in the mantle of the Baltic Sea corresponds to both the Gdansk Gulf of the Baltic Sea and the Kaliningrad fields (southeast of the Baltic Sea).

Baseline Studies and Risk Analyses in the Baltic Sea

1991 ◽  
Vol 1991 (1) ◽  
pp. 81-86
Author(s):  
Klavs Bender ◽  
Preben Østfeldt ◽  
Hanne Bach
Keyword(s):  
Baltic Sea ◽  
Oil Spill ◽  
Oil And Gas ◽  
Source Rocks ◽  
The Baltic Sea ◽  
Oil Companies ◽  
Total Hydrocarbon ◽  
Hydrocarbon Content ◽  
The Baltic ◽  
Total Hydrocarbon Content

ABSTRACT In 1986 an oil and gas concession in the Baltic Sea was granted by the Danish Ministry of Energy to a group of oil companies, with Norsk Hydro as operator. A paper describing the goals achieved midway through the program was presented at the 1989 Oil Spill Conference in San Antonio, Texas. This paper presents the final results of the program. The chemical baseline study has shown that the only parameter that exhibits a marked variation is the total hydrocarbon content, where values are seven to eight times higher in the 1989 samples than in the 1987 and 1988 samples. It is suspected that the reason is seasonal variation, since the 1989 samples were collected in June, while the 1987 and 1988 samples were collected in September. Even though the total hydrocarbon content varies significantly between some of the sample suites, only biomarkers related to recent organic material or immature petroleum source rocks are present in the samples. Petrogenic hydrocarbons related to spilled crude oil or exploration activities were not found in the area. The spreading and weathering calculations revealed the zones along the coast where an oil spill was most likely to occur. The transport time for an oil spill to reach the coast was also calculated by the model. In combination with mapping of sensitive resources, the results from the model test runs were used in risk assessments. The information gained in this study was used in the oil spill contingency plan.

scholarly journals Fine scale population structure linked to neutral divergence in the common sole (Solea solea), a marine fish with high dispersal capacity

2019 ◽  
Author(s):  
Alan Le Moan ◽  
Belén Jiménez-Mena ◽  
Dorte Bekkevold ◽  
Jakob Hemmer-Hansen
Keyword(s):  
Baltic Sea ◽  
Transition Zone ◽  
Structured Populations ◽  
Fine Scale ◽  
The Baltic Sea ◽  
Evolutionary Processes ◽  
Solea Solea ◽  
The Common ◽  
The Baltic ◽  
Common Sole

AbstractThe Baltic Sea provides a classical example of how an environmental gradient is associated with the distribution of marine species. Here, numerous genetic studies have revealed clear patterns of population structuring linked to the physical features of the gradient itself. Nevertheless, it remains difficult to distinguish clearly between the different micro-evolutionary processes that shape these structured populationsin situ. The common sole (Solea solea) is a benthic flatfish that rarely occurs within the Baltic Sea, but that exhibits a clear genetic break between populations from the North Sea – Baltic Sea transition zone and the remainder of the Atlantic Ocean. Here, we aim to evaluate the extent to which natural selection is involved in the observed patterns of divergence of sole populations occurring in the transition zone by comparing them with population structures of other flatfish species that have successfully colonized the Baltic Sea. By using several thousand of ddRAD-derived SNPs, we identified a fine-scale pattern of isolation-by-distance (IBD) of sole populations in the region. However, despite strong biological similarities among the flatfishes compared here, the sole IBD was, by far, the lowest detected across the transition zone. While selection was inferred to strongly influence all other flatfishes evolutionary histories, the analytical inference on the sole demographic history suggests that this fine-scale IBD is mainly maintained by neutral processes due to low effective population size of sole in the transition zone and asymmetrical gene flow. Our work contributes to a growing body of evidence suggesting that the strength of the different micro-evolutionary processes is species-specific, even when species occur in the same environment.

OIL SPILL CONTINGENCY PLANNING IN THE BALTIC SEA

1989 ◽  
Vol 1989 (1) ◽  
pp. 225-230
Author(s):  
Klavs Bender ◽  
Preben Østfeldt ◽  
Poul Kronborg
Keyword(s):  
Baltic Sea ◽  
Oil Spill ◽  
Oil And Gas ◽  
Contingency Planning ◽  
Status Report ◽  
Base System ◽  
The Baltic Sea ◽  
Oil Companies ◽  
The Baltic ◽  
Advanced Computer

ABSTRACT In 1986 an oil and gas concession in the Baltic Sea was granted by the Danish Ministry of Energy to a group of oil companies with Norsk Hydro as operator. In this connection, the company initiated a three-year research project in the area, covering the following subjects:The use and development of analytical methods for biomarkers, prior to any oil spill, to identify oil in marine sedimentsBaseline evaluation at 10 sediment stations within the concession area of certain defined heavy metals and hydrocarbonsSimulation of drift, spreading, and fate of oil slicks using advanced computer models calibrated for the Baltic Sea areaCoastal vulnerability mapping of resources and development of a computerized data base system for this information. This paper is a status report on the research, describing the goals achieved midway through the program.

scholarly journals Salinity Driven Selection and Local Adaptation in Baltic Sea Mytilid Mussels

2021 ◽  
Vol 8 ◽  
Author(s):  
Loreen Knöbel ◽  
Jennifer C. Nascimento-Schulze ◽  
Trystan Sanders ◽  
Dominique Zeus ◽  
Claas Hiebenthal ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Local Adaptation ◽  
Transition Zone ◽  
Selective Pressure ◽  
Future Climate Change ◽  
Larval Performance ◽  
The Baltic Sea ◽  
Low Salinity ◽  
The Baltic ◽  
Eastern Baltic

Baltic blue mussels can colonise and dominate habitats with far lower salinity (<10 psu) than other Mytilus congeners. Pervasive gene flow was observed between Western Baltic Mytilus edulis living at high salinity conditions and Eastern Baltic M. trossulus living at lower salinites, with highest admixture proportions within a genetic transition zone located at intermediate salinities (Darss Sill area). Yet, we do not understand the impacts of low salinity on larval performance, and how salinity may act as an early selective pressure during passive larval drift across salinity gradients. This study tested whether larvae originating from two different populations along the natural salinity cline in the Baltic Sea have highest fitness at their native salinities. Our results suggest that Eastern Baltic M. trossulus (Usedom, 7 psu) and Western Baltic M. edulis (Kiel, 16 psu) larvae display better performance (fitness components: growth, mortality, settlement success) when reared at their respective native salinities. This suggests that these populations are adapted to their local environment. Additionally, species diagnostic markers were used for genetic analyses of transition zone (Ahrenshoop, 11 psu) mussel larvae exposed to low salinity. This revealed that low salinity selection resulted in a shift towards allele frequencies more typical for Eastern Baltic M. trossulus. Thus, salinity acts as a selective pressure during the pre-settlement phase and can shape the genetic composition of Baltic mussel populations driving local adaptation to low salinity. Future climate change driven desalination, therefore, has the potential to shift the Baltic Sea hybrid gradient westward with consequences for benthic ecosystem structure.

scholarly journals Containerisation in the Baltic Sea Region: Development, Characteristics and Contemporary Organisation

2019 ◽  
Vol 26 (1) ◽  
pp. 9-25
Author(s):  
Arnaud Serry
Keyword(s):  
Soviet Union ◽  
Baltic Sea ◽  
Western Europe ◽  
Oil And Gas ◽  
Driving Forces ◽  
System Development ◽  
The Baltic Sea ◽  
The Soviet Union ◽  
Baltic Sea Region ◽  
The Baltic

The main focus of the paper is on the container system development in the Baltic Sea Region studying cotemporary changes and organisation, as well as explaining the main driving forces of this situation. The Baltic Sea is a transport corridor between Eastern and Western Europe. Over the last decade maritime transport in the Baltic Sea area has changed significantly. The disintegration of the Soviet Union forced Russia to start developing its own Baltic ports and terminals and to find new routes to export its oil and gas. The Baltic ports have welcomed a remarkable growth, especially in oil transportation and containerised flows. The geographical configuration of the region naturally places it away from major global shipping lines. This situation is accentuated by the organisation of maritime regular lines, centred in Northern European ports. For this reason, the regional container network is mainly made up of feeder services.

scholarly journals Spruce forests (Ass. Sphango girgensohnii - Piceetum (Br.-Bl. 39) Polak. 62) on excessively moistened peatlands in Latvia

2014 ◽  
Vol 62 (3-4) ◽  
pp. 199-202 ◽  
Author(s):  
Normunds Priedits
Keyword(s):  
Baltic Sea ◽  
East European Plain ◽  
Forest Site ◽  
The Baltic Sea ◽  
Swamp Forest ◽  
East European ◽  
Spruce Forests ◽  
Tree Layer ◽  
Baltic Sea Region ◽  
The Baltic

The research carried out on swamp spruce forests on peatland in Latvia gives a detailed notion of the phytosociological structure of Ass. <i>Sphagno girgensohnii - Piceetum</i> (Br. - BI. 39) Polak. 62 in the western part of the East-European Plain at the Baltic Sea. The paper reflects one of the aspects of swamp forest investigation results in Latvia on forest communities, its biodiversity and presevation. Ninety-one sample plots with <i>Picea abies</i> as the dominant in the tree layer or co-dominant with <i>Betula pendula</i>, <i>Betula pubescens</i> or <i>Pinus sylvestris</i> are described according to phytosociological Braun-Blanquet methodology. Floristic features of spruce communities belonging to <i>Caricoso-phragmitosa</i> and <i>Dryopterioso-cnricosa</i> forest site types are analysed. The results are compared with similar investigations carried out in the Baltic Sea region states and neighbouring countries.

Stability, genotypic and phenotypic diversity ofShewanella balticain the redox transition zone of the Baltic Sea

2014 ◽  
Vol 16 (6) ◽  
pp. 1854-1866 ◽  
Author(s):  
Jie Deng ◽  
Ingrid Brettar ◽  
Chengwei Luo ◽  
Jennifer Auchtung ◽  
Konstantinos T. Konstantinidis ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Transition Zone ◽  
Phenotypic Diversity ◽  
The Baltic Sea ◽  
Redox Transition ◽  
The Baltic
Sign in / Sign up

Export Citation Format

Share Document