BS4 Maritime transport
The number of visits to Finnish harbours almost doubled between mid 1980s and early 2000s. During the past three years the numbers of arriving roro vessels has decreased slightly. This has resulted in a decrease in the overall figures too. More than half of the ships arriving in Finnish harbours are roro ships, meaning ships designed to carry wheeled cargo such as trucks or railroad cars.
Oil transportation has increased significantly in the Gulf of Finland during the last decade. Increase has been the greatest in Russia, where new oil ports have been put into operation in the eastern part of the Gulf of Finland. Estonian ports were important already during the Soviet era, and have since then gained even more signifigance. The growth has been a lot slower in Finland, even though for example in port of Sköldvik (Porvoo) the annual oil transportation has increased from about 13 to 19 million tonnes during 1990-2007.
Impact on biodiversity
Maritime transportation has both direct and indirect impacts on the ecology of the Baltic Sea communities. The direct impacts consist mainly of the disturbance and erosion caused by moving vessels. Direct impacts also include oil spills. Indirect impacts result from the building and maintenance of the infrastructure supporting sea traffic.
A significant threat arising from increased sea traffic is the arrival of invasive species into the Baltic Sea. Invasive species are transferred from other marine areas especially in the vessels' ballast water tanks or attached to their hull. Some of the new species are likely to have strong impacts on the ecosystems and biodiversity of the Baltic Sea, through for example increased competition and changes in habitats and species interactions as well as community structure.
Illegal oil releases have been common in the Baltic Sea area. In 2001, 107 oil spills were observed in Finnish territorial waters. It is estimated that the amount of various size oil spills for the whole Baltic Sea varies from 500–800 per year. This continuous load is estimated to be more harmful for the ecosystem than any of the major oil accidents so far.
Organisms receive oil compounds from food or directly through their surface. In the organism the compounds act as toxins causing cell and tissue changes. The ability to endure oil in the habitat is species dependent. For example the amphipod Monoporeia affinis is very sensitive, but other species like the bivalve Macoma balthica survive a little longer. Fishes are usually not directly harmed by oil spills, since they actively move away, but the oil sinking to the seabed destroys spawning areas. Birds and mammals mostly suffer from oil staining, which at its worst harms feeding and breathing.
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- Updated (14.05.2013)