Ulla Rosenström

The most typical phytoplankton taxa in four types of boreal lakes

The monitoring of phytoplankton quantities and species composition in Finnish lakes started in the early 1960s. In addition, a substantial number of physical and chemical variables have been measured and recorded from the monitored lakes. The purpose of the present evaluation is to differentiate the phytoplankton taxa of the lakes being classified as acidic, oligotrophic, dystrophic and eutrophic. At present, these four lake types are differentiated on the bases of concentration of total phosphorus (µg l-1), water colour (mg l-1 Pt), and Secchi-disc transparency. A total of 38 lakes with 163 samples from the years 1984 to 1994 were selected for this study.Cyanoprokaryota Merismopedia warmingiana (M. tenuissima) was abundant in clear and dystrophic acidic lakes whereas Dinobryon divergens (Chrysophyceae) was dominant only in the clear lake types. Oocystis rhomboidea (Chlorophyceae) was also an important species, especially in the dark acidic lakes. In oligotrophic lakes, the phytoplankton biomass was low because of the combined effect of low organism numbers and small cell size of the occurring species. Additional chrysophyceans like Uroglena americana, unidentified Ochromonadales and Dinobryon divergens were especially abundant, as well as Merismopedia warmingiana. In the dystrophic lakes flagellated taxa, such as Cryptomonas spp., Uroglena americana, Ochromonadales and Pseudopedinella spp. dominated. In eutrophic lakes, the cyanoprokaryotes Microcystis aeruginosa, M. viridis and M. wesenbergii, as well as Anabaena flos-aquae and Aphanizomenon flos-aquae dominated both cell numbers and biomass. Some identification problems are also discussed.

Participation and empowerment-based development of socio-cultural indicators supporting regional decision-making for eco-efficiency

Abstract This article describes a process of developing socio-cultural indicators to support local and regional decision-making for eco-efficiency. Although eco-efficiency is calculated using environmental and economic variables, decisions on local and regional levels cannot ignore the socio-cultural impacts. The indicators were developed by a participatory process that was based on involvement and empowerment of local actors. The process ensured policy relevance and meaningful indicators and advanced their future use in the decision-making.