Status of Biodiversity in the Baltic Sea

The brackish Baltic Sea hosts species of various origins and environmental tolerances. These immigrated to the sea 10,000 to 15,000 years ago or have been introduced to the area over the relatively recent history of the system. The Baltic Sea has only one known endemic species. While information on some abiotic parameters extends back as long as five centuries and first quantitative snapshot data on biota (on exploited fish populations) originate generally from the same time, international coordination of research began in the early twentieth century. Continuous, annual Baltic Sea-wide long-term datasets on several organism groups (plankton, benthos, fish) are generally available since the mid-1950s. Based on a variety of available data sources (published papers, reports, grey literature, unpublished data), the Baltic Sea, incl. Kattegat, hosts altogether at least 6,065 species, including at least 1,700 phytoplankton, 442 phytobenthos, at least 1,199 zooplankton, at least 569 meiozoobenthos, 1,476 macrozoobenthos, at least 380 vertebrate parasites, about 200 fish, 3 seal, and 83 bird species. In general, but not in all organism groups, high sub-regional total species richness is associated with elevated salinity. Although in comparison with fully marine areas the Baltic Sea supports fewer species, several facets of the system's diversity remain underexplored to this day, such as micro-organisms, foraminiferans, meiobenthos and parasites. In the future, climate change and its interactions with multiple anthropogenic forcings are likely to have major impacts on the Baltic biodiversity

High-temperature materials for power generation in gas turbines

The chapter describes the different aspects of ceramic materials in gas turbines. The operation conditions such as high-pressure ratio and high temperatures result in improved efficiencies and make necessary the use of materials with high-temperature capability. In addition to the often used single-crystal alloys ceramic materials are discussed. Different bulk ceramics, for example, based on silicon nitride are described. A special focus is laid on ceramic matric composites, both oxide and nonoxide-based materials, which are of increasing interest for gas-turbine applications.In addition to the structural applications ceramics are also often used as coating material. Standard coating processes for protective coatings in gas turbines are described. Furthermore, thermal barrier coatings, a widely used coating system in gas turbines, and environmental barrier coatings as protective coatings for ceramic matrix composites are discussed in detail. Finally, also degradation and failure modes for the different high-temperature coating systems are the topics of thi

High-temperature materials for powergeneration in gas turbines

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