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1.
The loading effect of the Baltic Sea is immediately recognizable in the gravity record of the superconducting gravimeter T020 in Metsähovi, Finland, by simply inspecting residual gravity together with the tide gauge record at Helsinki 30 km away. The station is 10 km from the nearest bay of the Baltic Sea and 15 km from the open sea. Sea level variations in the Baltic are non-tidal and driven at short periods primarily by wind stress, at longer periods by water exchange through the Danish straits. Locally they can have a range of 2–3 m. Loading calculations show that a uniform layer of water covering the complete Baltic Sea increases the gravity in Metsähovi by 31 nm/s2 per 1 m of water, and the vertical deformation is −11 mm. The observed gravity response to the local sea level is generally less, since the variations at short periods are far from uniform areally, the same water volume just being redistributed to different places. Regression of the whole gravity record (1994-2001) on local sea level gives 50–70% of the uniform layer response, as do loading calculations using actual water distributions derived from 11 tide gauges. However, both fits are dominated by some extreme values of short duration, and parts of the gravity record with long-period variations in sea level are close to the uniform layer response. The gravity observations can be used to test corrections for other co-located geodetic observations (GPS, satellite laser ranging) which are influenced by the load effect but not sensitive enough to discriminate between models.  相似文献   

2.
Loading by atmosphere and by the Baltic Sea cause gravity change at Metsähovi, located 15 km from the open sea. Gravity is changed by both the Newtonian attraction of the loading mass and by the crustal deformation. We have performed loading calculations using appropriate Green's function for both gravity and deformation, for both atmospheric and Baltic loading. The loading by atmosphere has been computed using a detailed surface pressure field from high resolution limited area model (HIRLAM) for north Europe up to 10° distances. Baltic Sea level is modelled using tide gauge records. Calculations show that 1 m of uniform layer of water corresponds to 31 nm s−2 in gravity and −11 mm in height. Modelled loading is compared with observations of the superconducting gravimeter T020 for years 1994–2002. The combination of HIRLAM and a tide gauge record decreases RMS of gravity residuals by 14% compared to single admittance in air pressure corrections without sea level data. Regression of gravity residuals on the tide gauge record at Helsinki (at 30 km distance) gives a gravity effect of 26 nm s−2 m−1 for Baltic loading.The gravity station is co-located with a permanent GPS station. We have also associated the loading effects of the atmosphere and of the Baltic Sea with temporal height variations. The range of modelled vertical motion due to air pressure was 46 mm and that due to sea level 18 mm. The total range was 38 mm. The effects of the Baltic Sea and of the atmosphere partly cancel each other, since at longer periods the inverse barometer assumption is valid. Regression of the modelled height on local air pressure gives −0.37 mm hPa−1, corresponding approximately to width 6° for pressure system.We have tested the models using one year of daily GPS data. Multilinear regression on local air pressure and sea level in Helsinki gives the coefficient −0.34 mm hPa−1 for pressure, and −11 mm m−1 for sea level. These match model values. Loading by air pressure and Baltic Sea explains nearly 40% of the variance of daily GPS height solutions.  相似文献   

3.
A major task in developing a management strategy for the Baltic Sea will be the establishment of a program that adheres to the philosophy of sustainable use and is capable of implementation. For many nations this has proven to be a very difficult task marked with successes and failures. This paper discusses North Carolina's attempts to move toward sustainability in its Albemarle and Pamlico estuaries. The paper concludes with some lessons learned that could be helpful to the Baltic region as it strives for sustainability.  相似文献   

4.
Miettunen  Elina  Tuomi  Laura  Myrberg  Kai 《Ocean Dynamics》2020,70(11):1421-1437
Ocean Dynamics - We studied the water age and transport of passive tracers in the Archipelago Sea, Baltic Sea, using the COHERENS 3D hydrodynamic model and the OpenDrift Lagrangian particle model....  相似文献   

5.
Politics, economics and science interpret the concept of sustainability differently. The discussion distinguishes between economic, environmental and social sustainability. While advocates of economic sustainability assume that natural capital is substitutable by humanmade capital, policies for a sustainable development are questionable. The paper therefore highlights a regional case to show that sustainability is indivisible. Moreover, economics and policies serving Baltic sustainability need a new institutional network to manage the multispecies resource with participation of the social players and by addressing targets step by step. The findings are based on a simple ecological-economic model providing insights for the negotiation game for all players. In addition, multispecies resource management shows a strong hierarchy in both social actions and targets. Since sustainable development is an on-going, dynamic process, policy implementation and funding must also be continuous. Sustainable development therefore challenges the institutional sets for the process and its relations to local, regional and national policies.  相似文献   

6.
The Helsinki Commission (HELCOM) Baltic Sea Action Plan, adopted by the coastal countries of the Baltic Sea and the European Community in November 2007, is a regional intergovernmental programme of measures for the protection and management of the marine environment explicitly based on the Ecosystem Approach. The Action Plan is structured around a set of Ecological Objectives used to define indicators and targets, including effect-based nutrient input ceilings, and to monitor implementation. The Action Plan strongly links Baltic marine environmental concerns to important socio-economic fields such as agriculture and fisheries and promotes cross-sectoral tools including marine spatial planning. Due to complementarities with the European Union (EU) Marine Strategy Framework Directive, the Action Plan is in essence a pilot for this process without neglecting the important role of the Russian Federation - the only Baltic coastal country not a member of the EU.  相似文献   

7.
The review provides an overview of the features of the North Sea and the Baltic Sea in their European geographical and socio-political context. To reach sustainability in the wider sense the common society has to meet the 7 tenets - that management actions have to be environmentally sustainable, economically viable, technologically feasible, socially desirable (or at least tolerable), legally permissible, administratively achievable and politically expedient. Each of these are explained and discussed using examples from the two seas including pollution control, physical resource exploitation (such as aggregates, habitat loss, renewable energy and oil and gas), and biological resources exploitation (fisheries and aquaculture). This paper discusses the similarities between the areas in terms of their management regimes, population in the catchment, history of anthropogenic changes, derivation of objectives against a wealth of information and understanding, and the history of management and control. In contrast, the differences between the areas centre on their differing hydrographic regimes, including residence and flushing times, biological features, nature of the pollutants discharged, dominant types of fishing and type of control indicated by a predominant Eastern Bloc for the Baltic as opposed to European Union control in the North Sea. The review ends with an assessment of future challenges and examples of the way in which environmental problems have been addressed in the two areas. In particular, it sets the features against a background of management designed to achieve the Ecosystem Approach within the prevailing European marine management framework.  相似文献   

8.
The herbicides atrazine, simazine and terbuthylazine (and the degradation product deethylatrazine) were analysed in two river-to-open-sea transects and two vertical (open-sea) profiles in the southern Baltic off Poland. Samples taken in September 1995 and April 1997 contained total triazine concentrations ranging from 7 to 31 and 4.5 to 13 ng/dm3, respectively. Concentrations of the individual compounds ranged from 0 to 8 ng/dm3. These are generally higher than levels reported, for example, in the North Sea. The largest surface concentrations were found close to the Vistula and Odra river mouths, endorsing river run-off as a primary source of the triazines. Temporal variability can be related to the late-spring and early-summer agricultural applications of the compounds. Variations in ratios between the individual triazines can be explained by usage patterns and differing residence times. Offshore vertical profiles indicate enrichment of the surface layer through atmospheric triazines inputs, highest concentrations above the halocline associated with colloidal organics and lowest concentrations in the bottom waters, probably as a result of particulate scavenging. The influence of the North Sea inflow to the Baltic is also discussed.  相似文献   

9.
Poland largely encompases the estuary of the Vistula and Odra rivers, which drain into the Baltic Sea. Only a very small area of the south-east part of the country is within the Black Sea Basin. Poland contributes significantly to the pollution of the Baltic Sea, with biogenic nutrients and organic substances. Poland includes more than half the coastal inhabitants of the Baltic Sea, and they use 40% of the arable land situated there. The contribution to the pollution of this sea with nitrogen, phosphorus and organic substances is approximately 30, 40 and 22%, respectively. The main sources of nutrients are untreated sewage and the runoff and leakage of fertilizers from agricultural land. The natural conditions in Poland are poorer than in Western Europe due to the prevalence of light soils and a short growing period with frequent droughts. After correcting the synthetic index for soil and climate, it was estimated that for each inhabitant of Poland there are 0.3 ha of farmland, which is comparable to that of Western Europe. For the maintenance of the population, intensive agricultural production must be accompanied by environmental protection regulations. Polish agriculture is not only a polluter but also a recipient of pollution, especially the deposits of sulphur and heavy metals emitted by industry and municipal areas. The estimated annual emission of sulphur dioxide is about 4 million t, which equals an average deposit of about 90 kg of sulphur per hectare of farmland. The pedological processes and acid deposits cause more than 60% of agricultural land in Poland to be acidic. The contamination of soils with heavy metals in general is lower than in Western Europe, but in some areas (e.g. Upper Silesia) it exceeds the safe limits.  相似文献   

10.
The rivers in the Baltic Basin drain a mixture of bedrocks ranging from Mesozoic-Paleozoic sediments in the south to Proterozoic-Archean intrusives in the north. The rivers in the sedimentary basin in the south have high concentrations of Sr, in the interval 100–500 µg l–1 while the87Sr/86Sr ratio is close to that of seawater, i.e. 0.71. The northern rivers in the Precambrian shield area on the other hand have low Sr concentrations of 15–50 µg l–1 with high87Sr/86Sr ratios of about to 0.73 (0.721–0.745). The riverine input of dissolved Sr to the brackish Baltic Sea approaches 60 tons year–1, with a weighted mean concentration approaching 130 µg l–1 and a weighted mean87Sr/86Sr ratio close to 0.712. Although the sedimentary area in the south supplies only about 43% of the total river discharge, it gives about 88% of the total Sr input. Because of this and the strong regional riverine variation in87Sr/86Sr ratio, Sr and its isotopes seem to be a convenient tool to unveil mixing relations of water masses in the northern Baltic Sea, provided high resolution analyses are applied. For an overall characterization of water mixing in the Baltic Sea, the Nd system will be superior to that of Sr.  相似文献   

11.
The levels of copper, zinc, manganese and iron were determined in samples of the filamentous green alga Cladophora glomerata collected from the northern Baltic Sea in the Finnish Archipelago Sea. Cu, Zn and Mn did not reveal any observable trends according to the plants' habitats. In clear contrast, the levels of iron in the algae collected from soft-bottom habitats exceeded highly significantly all the values recorded for the rocky and stony shore types.  相似文献   

12.
Species pattern of phytoplankton in the surface waters (0–1 m) of the Baltic Sea was studied in the autumn 1991 during 25th cruise of the R/V “Akademik Mstislav Keldysh”. The samples were analysed by light and scanning electron microscopy. Results of this work show that sharp changes in the Central Baltic phytoplankton community have not yet begun. In coastal eutrophicated waters the growth of biomass and decrease of phytoplankton diversity are more significant.  相似文献   

13.
Henn Ojaveer   《Limnologica》1999,29(3):224
The main exploitable biological resources in the Estonian zone of the Baltic Sea are fish stocks. Fishes of marine origin constitute the main bulk (on the average 91%) of catches. Some freshwater and migratory fishes, having usually only marginal role in the total weight of fish landings, are of special importance for local fishermen in certain regions. Other living resources — red algae and seals-have been exploited in rather small amounts.The main factors having controlled changes in the condition of fish stocks and catches are natural conditions, marine pollution, eutrophication and exploitation rate.  相似文献   

14.
This study reports the occurrence of shell deformities in the Baltic clam Macoma balthica from the Northern Baltic Sea (Trösa Archipelago, Sweden). The functional significance and the bioindicative potential of observed exoskeleton’ anomalies was assessed using a suite of physiological and morphological biomarkers.Analyzed shell deformations (SD) included damages of the dorsal margin visible as shell excavations, destruction of the beak, umbo and hinge ligament and decreased shell’ transparency. Deformed clams exhibited worse physiological conditions and increased frequency of micronuclei. Skewed sex ratio towards male domination was observed in all studied populations. Spatial differences in the occurrence of deformed clams are reported, with more than 50% of deformed clams inhabiting polluted locations and 8% the reference station. These results are encouraging for the use of described SDs as initial and cost effective indicators of environmental health.  相似文献   

15.
In the Baltic Sea eutrophication processes have accelerated in the past 50 years of the 20th century and presently there exists a major ecological problem for this sea. The Polish coastal zone of the southern Baltic Sea is the recipient of riverine inputs from two major sources, namely the Odra and Vistula, as well as a number of smaller rivers along the central coast. Hence, the entire coastal zone remains under severe anthropogenic pressure. The variability of nutrient concentrations, especially the winter nutrient pool in the euphotic zone, summer level of total nitrogen and total phosphorus, together with such eutrophication indicators as water oversaturation with oxygen and the summer oxygen minimum, were analysed in the data time series 1959-2001. The temporal trends were investigated using linear regression and the non-parametric Whirsch test. The future characteristics of the Baltic Sea are discussed taking into account the development of driving forces.  相似文献   

16.
The monitoring programme of harmful substances in selected species in the Baltic Sea was started in 1979. In the present study, three-year averages of Zn, Cu, Cd and Pb in cod liver (Hg in cod muscle) and herring muscle are reported. The concentrations of heavy metals in cod show areal differences roughly in accordance with the concentrations of heavy metals in sea water. No significant differences between heavy metal concentrations in North Atlantic and Baltic Sea species were found, except for mercury, for which values in the Baltic Sea species are lower than in those from the North Atlantic.  相似文献   

17.
There is an increasing understanding and requirement to take into account the effects of invasive alien species (IAS) in environmental quality assessments. While IAS are listed amongst the most important factors threatening marine biodiversity, information on their impacts remains unquantified, especially for phytoplankton species. This study attempts to assess the impacts of invasive alien phytoplankton in the Baltic Sea during 1980-2008. A bioinvasion impact assessment method (BPL - biopollution level index) was applied to phytoplankton monitoring data collected from eleven sub-regions of the Baltic Sea. BPL takes into account abundance and distribution range of an alien species and the magnitude of the impact on native communities, habitats and ecosystem functioning. Of the 12 alien/cryptogenic phytoplankton species recorded in the Baltic Sea only one (the dinoflagellate Prorocentrum minimum) was categorized as an IAS, causing a recognizable environmental effect.  相似文献   

18.
Summary Major Baltic inflows (from the Kattegat) represent the only possibility for deep water renewal in the Baltic Sea that is generally characterised by stable stratification. Such an inflow occurred in January 1993 for the first time in 16 years. Observations were made by a moored station at Darß Sill and, for the first time since investigations into major Baltic inflows began, by a research vessel. In addition, the event has been simulated in an operational model.
Der Salzwassereinbruch vom Januar 1993 in die Ostsee-Messungen und Modellergebnisse
Zusammenfassung Für die im allgemeinen stabil geschichtete Ostsee bilden Salzwassereinbrüche (aus dem Kattegat) die einzige Möglichkeit zur Erneuerung des Tiefenwassers. Ein solcher Salzwassereinbruch ereignete sich nach 16 Jahren Unterbrechung erst wieder im Januar 1993. Dieser Vorgang wurde durch Messungen von einer permanenten Station auf der Darßer Schwelle und — erstmals in der Geschichte der Erforschung von Salzwassereinbrüchen —einem Forschungsschiff registriert. Außerdem liegt eine numerische Simulation mit einem operationellen Modell vor.
Insertion d'eau salée dans la mer Baltique en janvier 1993. Mesures et exploitation d'un modèle numérique
Résumé L'apport d'eau salée en provenance du Kattegat reste la seule possibilité de renouvellement des eaux profondes des couches stables de la mer Baltique. Un telle insertion d'eau salée ne s'est produite qu'au mois de janvier 1993 après une interruption de 16 ans. Ce processus a été enregistré par des mesures d'une station permanente (Darßer Schwelle) et, pour la première fois dans l'histoire de l'étude des insertions d'eau salée, par un navire scientifique. En outre une simulation numérique à l'aide d'un modèle opérationnel est présentée.
  相似文献   

19.
A detailed analysis of the short and medium term dynamics of the carbon exchange between the Baltic Sea and the North Sea is presented. To quantify the carbon fluxes distinguishing the Baltic and North Sea water masses, the salinity-based End Members (EM) method was successfully applied. The results of 0.63±0.25×1012 mol C year−1 identify the Baltic Sea as a net source of carbon for the North Sea. Dissolved organic carbon (DOC) was found to contribute significantly (22%) to the bulk of exported carbon. The levels determined suggest the hydrology-dependence of the carbon fluxes in the Danish Straits, which stimulates the high variability of carbon fluxes at both interseasonal and interannual scales.  相似文献   

20.
Common eiders nesting in the Baltic Sea are exposed to generally high levels of contaminants including potentially genotoxic polycyclic aromatic hydrocarbons and organochlorines. Blood samples were collected from eiders at eight sites in the Baltic Sea and two sites in the Beaufort Sea. DNA content variation was estimated using the flow cytometric method, and subsequently utilized as a biomarker of genetic damage. We observed no significant differences in genetic damage among populations within either the Baltic or Beaufort Seas. However, eider populations from the Baltic Sea had significantly elevated estimates of genetic damage compared to populations from the Beaufort Sea.  相似文献   

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