Rila Mountains Research Articles

Air Pollution Status of the Bulgarian Govedartsi Ecosystem

Coniferous forests cover one-third of Bulgaria’s forest ecosystems and occupy 31% of the country’s total area. Forests in general are considered vulnerable to air pollutants in the form of dry and wet pollution deposition. The Bulgarian Govedartsi ecosystem study site, Ovnarsko No. 3, was established in 1991 to: (1) determine the existing status of remote forest site air quality; and (2) address potential air pollution problems related to coniferous forests. The site (1600 m) is located on the south slope of the Govedartsi Valley in the northwestern part of the Rila Mountain area. The Rila are the highest mountains (peak 2925 m) in the Balkan peninsula and are representative of rural forested conditions in that part of Europe. There are no anthropogenic air pollution sources for at least 30 km in all directions. The dominant tree species surrounding the study site include Scotch pine ( Pinus sylvestris L.), Macedonia pine ( Pinus peuce), black pine ( Pinus nigra Arn.), Norway spruce ( Picea abies Karst.), white fir ( Abies alba Mill.), beech ( Fagus sylvatica L.), and several oak species (i.e. Quercus petraea Liebl, Q. pubescens Willd., Q. conferta Kit., Q. cerris L., and Q. robur). Multi-day average ambient concentrations of nitrate and sulfate were measured using a filter-pack technique. Data for 27 multi-day periods between October 1991 and 1994 have been collected and 24 are reported in this study. Annual acidic aerosol dry deposition values are estimated at: 154 kg km −2 for sulfate ( SO 2− 4) and 28 kg km −2 for nitrate ( NO − 3). Ozone (O 3) concentrations were measured from late spring to summer in 1994 and 1995. No high O 3 concentration episodes were detected, and maximum hourly O 3 concentrations rarely exceeded 55 ppb.

Fish production in the Mesta River, Rila Mountain, Samokov, Bulgaria

Fish production was estimated at five sites in the upper course of the Mesta River. Eight species were caught, and their diversity increased downstream. Population estimates were made with the three-sample maximum-likelihood Zippin method. Density, standing crop, average biomass and production (based on the mortality curve) were 1468–17060 ind. ha −1, 40.4–319.0 kg ha −1, 15.8–222.5 kg ha −1 and 20.1–177.1 kg ha −1 a −1, respectively. Total production estimates based on total fecundity were 33.8–77.7% (mean 52.4) higher than these values. Brown trout production contributed 28–99% of the total production at all the sites. Total production was highest at the sites which were deepest and had the lowest water velocity.

Beiträge zur kenntnis algenparasitärer Phycomyceten VII. Über Phlyctochytrium planicorneAtkinson 1909

Summary Finds of the Phycomycete Phlyctochytrium planicorne on Vaucheria geminata in the Harz mountains (new for Central Europe) and on Vaucheria undulata in the Rila mountains (P. R. Bulgaria) are reported. Based on cultures of the Harzmaterial stations of the lifecycle, including the resting spores are described.

An examination of some Hexarthra species (Rotatoria) from western Canada and Nepal

Four species of Hexarthra are reported from ponds and lakes in western Canada. Two Rocky Mountain forms are described as new subspecies: Hexarthra bulgarica canadensis n.subsp., at high altitudes, and Hexarthra polyodonta jasperina n.subsp. The nominate subspecies of the latter is known only from saline Lake Van, Turkey. Hexarthra polyodonta jasperina occurs in low salinity lakes and differs morphologically from the nominate subspecies in having a moderately developed ventro-anterior lip. Hexarthra bulgarica bulgarica is a true high-mountain rotifer known from the Rila Mountains, Bulgaria (nominate subspecies), from the Himalayas (H. bulgarica nepalensis n.subsp.), and from the Rocky Mountains (H. bulgarica canadensis n.subsp.). The Nepalese subspecies differs from the nominate subspecies and from H. bulgarica canadensis in having a well developed ventro-anterior lip. Hexarthra bulgarica canadensis differs from the nominate subspecies in having more teeth on the unci, more spines on the ventral arm, and more filaments on all arms. The pair of spines on the dorsolateral arm is the main diagnostic character of the H. bulgarica group. Hexarthra mira (Hudson) occurred at intermediate and lower altitudes, and Hexarthra fennica (Levander) was identified from a saline lake in Saskatchewan where specimens were unusually large, but otherwise typical.

Rare minerals of the spinel group in ultrabasites from Bulgaria

Chromite mineralization was found during a detailed geological mapping, carried out in 1962, in the region of the Seven Lakes, Northern Rila Mountain. Mineralogical studies showed that the ore minerals of this mineralization are of a great variety, and are members of the little known group of ferrospinels with varying chromium-, aluminium- and magnesium-content. Only three minerals are described in the present paper. They are well defined varieties, differing from one another by their chemical composition and physical properties.

The Rila mountains

The Rila mountains