The aim of this study is to determine the Cu(II) complexing capacity and stability constants of Cu(II) complexes of humic acids isolated from two well-characterized raised bog peat profiles in respect to the basic properties and humification characteristics of the studied peats and their humic acids. The complex stability constants significantly change within the studied bog profiles and are well correlated with the age and decomposition degree of the peat layer from which the humic acids have been isolated. Among factors that influence this complexation process, molecular mass and ability to form micellar structures (supramolecules) of humic substances are of key importance.
Petalomonas sphagnophila has been found for the first time in Russia from the Shichengskoe raised bog (Vologda Region). Morphology of the species is studied by means of light microscopy and illustrated by original micrographs. The data on its taxonomy, ecology and distribution are given. The name P. sphagnophila was not validly published because no type was indicated in the original publication (Christen, 1962), so we are validating the name by indicating its holotype. P. polytaphrena Skuja, nom. inval. is treated as a synonym of P. sphagnophila. Currently, thirty species of the genus Petalomonas, including P. sphagnophila, are known from Russia.
Highly humic lakes are typical for the boreal zone. These unique ecosystems are characterised as relatively undisturbed habitats with brown water, high acidity, low nutrient content and lack of macrophytes. Current lake assessment methods are not appropriate for ecological assessment of highly humic lakes because of their unique properties and differing human pressures acting on these ecosystems. This study proposes a new approach suitable for the ecological status assessment of highly humic lakes impacted by hydrological modifications. Altogether, 52 macroinvertebrate samples from 15 raised bog lakes were used to develop the method. The studied lakes are located in the raised bogs at the central and eastern parts of Latvia. Altered water level was found as the main threat to the humic lake habitats since no other pressures were established. A multimetric index based on macroinvertebrate abundance, littoral and profundal preferences, Coleoptera taxa richness and the Biological Monitoring Working Party (BMWP) Score is suggested as the most suitable tool to assess the ecological quality of the highly humic lakes.
How to Assess the Ecological Status of Highly Humic Lakes? Development of a New Method Based on Benthic Invertebrates