The Baltic is a unique brakish sea. Its moderate salinity is the result of the fresh river water input and non-periodic inflows of salty, oxygenated waters from the North Sea. However, the balance continually fluctuates. What impact does that have on the sea?
This article presents results of the analysis of 3 sediment cores taken from the bottom of Pomeranian Bay, southern Baltic Sea. These results are part of a larger project that aims to determine the characteristics and rate of the Atlantic marine ingression in the Pomeranian Bay area. The main geochemical elements and diatom assemblages from the cores were identified, revealing lacustrine sediments deposited during the time of Ancylus Lake and marine sediments deposited during the Littorina transgression. Distinct changes in the geochemical composition and diatom assemblages suggest that the Littorina transgression had a very large impact on the environment of Pomeranian Bay.
How does inflowing river water affect the quality of water in the Baltic Sea? Why are the chemicals used in agriculture so dangerous for seas, and what future lies in store for the Baltic?
The environment in general and the marine environment in particular forms an ecosystem. Such ecosystem is characterized by high interconnectivity and interdepen-dence of species inhabiting it. Often enough, marine ecosystems far exceed the limits of the State’s sovereignty. Thus, their effective protection and preservation shall be carried out on a cooperative basis, engaging all States sharing common environment. The first international treaty to tackle the issue of marine environmental protection on a systemic basis is the United Nations Convention on the Law of the Sea (UNCLOS). It is also a treaty which directly established an obligation to cooperate in ensuring this protection. However, homogenous international regulation is not capable of addressing regional varying circumstances of marine environment. As the example of the South China Sea shows, lack of cooperation between coastal States can result in an irreversible damage to the environment. On the other hand, a remarkable model of effective realization of the obligation to cooperate has been established in the region of the Baltic Sea. What we can learn from these experiences is that fulfillment of the obligation to cooperate on a re-gional basis is a prerequisite for effective protection and preservation of the marine environment.
The article presents the issues related to ecological security of the Baltic Sea. The issue was taken from the perspective of Poland as one of the Baltic States, and also as a Member State of the European Union. The authors discussed the mechanisms and legal instruments which are crucial for the ecological security of the Baltic Sea (i.e. Helsinki Convention of 1974, or Agenda 21 for the Baltic Sea Region “Baltic 21”). The importance of cross-border cooperation has also been emphasized as an essential element of the security policy in the Baltic Sea area. The article also indicated threats to the protection of Baltic waters, among others, eutrophication.
Nutrient emissions by point and diffuse sources and their loads were estimated for the Odra catchment over the time period of the last 50 years by means of the model MONERIS. For nitrogen a change of the total emissions from 38 kt·a–1 N in the mid of 1950s a maximum of 105 kt·a–1 N in the early 1980s and a recent value of about 84 kt·a–1 N were estimated for the total Odra Basin. The share of the point source discharges on the total N emissions varied between 24% (1955) and 35% (1995). The emissions from groundwater and tile drained areas represent the dominant pathway (37–56% of total N emissions) during all investigated time periods. Emissions from tile drained areas increased from the mid of 1950s to end of 1980s by a factor of 20 and reached in this period the same amount as emissions by groundwater. For phosphorus the emissions changed from 4 kt·a–1 P in 1955 to 14 kt·a–1 P in 1990 and a recent level of 7 kt·a–1 P. Point source discharges caused between 36 to 66% of total P emissions and represent the dominant pathway for all investigated time periods. Erosion and discharges from paved urban areas and sewer systems was the dominant diffuse pathway of the total P emissions into the river system. The comparison of calculated and observed nutrient loads for the main monitoring stations along the Odra River shows that the average deviation is 12% for total phosphorus (1980–2000) and 15% for dissolved inorganic nitrogen (1960–2000). From the analysis it can be concluded that the present load of dissolved inorganic nitrogen (DIN) and total nitrogen (TN) of the Odra into the Baltic Sea is about 2.3 times higher than in the mid of 1960s. The maximum DIN load (1980s) was more than 3 times higher than in the 1960s. The change of the total phosphorus (TP) load is characterized by an increase from the 1955s to 1980 from 2 to 7 kt·a–1 P (factor 2.6). Around 2000 the TP load was 4 kt·a–1 which is only the double of the level of the 1955s