Dissolved and suspended forms of caesium-137 in marine and riverine environments of the southern Baltic ecosystem

Dissolved and particulate activities of caesium-137 are presented for the coastal and open southern Baltic Sea waters, fluvial waters (the Vistula and Swina rivers) and lagoon waters (the Vistula Lagoon) during 1996-1999 and compared to those collected before the Chernobyl accident. 137Cs was measured in the Baltic Sea waters at different depths as well as 0.2-0.3 m above the sea bed. In a layer of the Gdafsk Bay waters (the Gdafsk Deep location), extending from the surface down to 1-2 meters above the sea bed, the caesium-137 concentrations ranged between 57 and 66 Bq m-3 in 1999, whereas in the layer situated 0.2-0.3 m above the sea bed its concentration increased up to 87 Bq m-3. This phenomenon was also observed in 1994 and 1998. The concentrations of caesium-137 in riverine suspended particulate matter (r SPM) are lower than in the marine SMP (m SMP) and its activity attains respectively 36 and 222 Bq kg-1 based on dry weight. The proportion of caesium-137 in the suspended form in the Baltic Sea waters does not exceed 2 per cent, while in the fluvial suspended form it is as high as 55 per cent

Genetic diversity in widespread species is not congruent with species richness in alpine plant communities

The Convention on Biological Diversity (CBD) aims at the conservation of all three levels of biodiversity, that is, ecosystems, species and genes. Genetic diversity represents evolutionary potential and is important for ecosystem functioning. Unfortunately, genetic diversity in natural populations is hardly considered in conservation strategies because it is difficult to measure and has been hypothesised to co-vary with species richness. This means that species richness is taken as a surrogate of genetic diversity in conservation planning, though their relationship has not been properly evaluated. We tested whether the genetic and species levels of biodiversity co-vary, using a large-scale and multi-species approach. We chose the high-mountain flora of the Alps and the Carpathians as study systems and demonstrate that species richness and genetic diversity are not correlated. Species richness thus cannot act as a surrogate for genetic diversity. Our results have important consequences for implementing the CBD when designing conservation strategies