Evaluation of Heavy Metal Level in Soil of Typical Alpine Grassland Communities

Objective: Through the investigation, determination and analysis of heavy metals in the soil of typical alpine grassland community, five kinds of alpine grasslands with different degeneration degree of Maduo County in Alpine area, two kinds of alpine grassland with high Maqu County, high Alpine desert along the coast of Qinghai Lake, alpine thickets in the yellow South region, Alpine wetlands, The condition of soil heavy metals in alpine meadow and other communities is analyzed, which provides scientific guidance for the ecological protection measures of typical alpine grassland communities, and provides a basis for the sustainable utilization of Alpine grassland. Methods: The content of various kinds of heavy metals in soil samples was determined by ICP-MS, and the pollution status of heavy metals was analyzed by means of single factor pollution index method, Nemero comprehensive pollution index method and potential ecological risk index method by using Excel. Results: (1) The content of Cd in Maduo, Maqu, Qinghai Lake and Huangnan was 1.74, 0.97, 1.84 and 1.06 times times the soil environment background respectively, and the content of Hg in Maqu was 1.36 times times that of soil environmental background value. The variation coefficient of Hg and Pb in Maqu and the coefficient of variation of Cd in Qinghai Lake are more than 100%, which is in the degree of high variation, which is greatly influenced by man. (2) The highest total pollution index in the 4 sample places was in the area of MA diversity, at 1.33. The second is the Huangnan sample, with an exponential value of 0.86. The Nemero comprehensive pollution Index of the Maqu sample is 0.77. The index value of Qinghai Lake sample is the lowest, at 0.61. (3) The highest potential ecological hazard index is the most diverse, in 0-10, 10-20, 20-30cm three soil layers are 96.96, 103.58, 102.46, Maqu in 0-10, 10-20cm soil, the potential ecological hazard index is 65.70, 71.01, the potential ecological hazard index of Huangnan in three soil layer is 78.23, 73.42 and 72.84 respectively, which refers to the smallest value of Qinghai Lake sample, three, 51.07 and 51.72 in 51.48 soil layer respectively. Conclusion: The Nemero comprehensive pollution Index of Qinghai Lake sample is less than 0.7, at the level of cleanliness, the exponential value of Huangnan and Maqu two samples is between 0.7~1, at the level of cordon, and the exponential value of ma variety is between 1~2, at the level of mild pollution. The comprehensive potential ecological hazard index of 80~160 has the potential ecological risk of strength, and the exponential value of the other three samples is between 40~80, which has medium potential ecological risk. Generally, the pollution degree of heavy metals is small in the whole alpine grassland area.

Research Into Biological Characterictics of Dried Sapropel

<p class="RTU-AbstractKeywords"><span lang="EN-GB">Microbiological characteristics of dried sapropel of Lake Rušona and Lake Ubagova and concrete containing sapropel and hemp sheaves (Ubagova Lake) have been studied. The antimicrobial activity was studied by the</span><span lang="EN-GB">reference test cultures</span><em><span lang="EN-GB">Staphylococcus aureus ATCC 25923, Salmonella enteritidis ATCC 13076, Enterococcus faecalis ATCC 29212, Bacillus cereus ATCC 10876, Escherichia coli ATCC 25922, Candida albicans ATCC 10231</span></em><span lang="EN-GB">. Antibacterial activity on <em>Staphylococcus aureus</em> reference test cultures is stated in Rušona Lake sample before treatment with UV rays. Antibacterial activity is not stated in Ubagova Lake sapropel sample. 20 minutes’ long UV ray treatment is not long enough to prevent the growth of sapropel materials. Both Rušona Lake and Ubagova Lake samples contain microorganisms that start growing and intensively reproducing in favourable conditions. When in contact with humidity, at the temperature from 18 to 37± 1 ⁰C, mold colonies form on concrete containing sapropel and hemp sheaves, for this reason this material should not get in contact with humidity when used in construction. </span></p>

Spatial Variation of Crustacean Plankton in Lakes of Different Size

The patterns of spatial distribution of planktonic crustaceans changed with increasing lake size. Greatest abundances were often found offshore in smaller lakes but nearshore in larger lakes. Interstation similarity of plankton, measured with Jaccard's and Renkonen's indices, was higher in small- to middle-sized lakes and lower in very small and very large lakes, indicating that mechanisms existed at both ends of the size spectrum which prevented plankton from mixing horizontally. The information content of a single central lake sample was evaluated against a lake average from 9–10 stations. To capture at least 80% of the species present, one station was sufficient only in smaller lakes, three to six stations were needed in the smallest and medium-sized lakes, and more than nine stations were needed in the largest lake. The single central station in small- and medium-sized lakes represented average total plankton abundance and dominant species relatively well but underestimated rare species. In larger lakes, lake average plankton was not well characterized by a single station. In Lake Superior, the central station reflected the offshore but not the nearshore community. Neither plankton abundance nor the number of species appeared related to lake size in the series of lakes investigated.

U–Pb zircon ages from the eastern Savant Lake – Crow Lake metavolcanic–metasedimentary belt, northwest Ontario

Five rocks from three areas in the eastern part of the Savant Lake – Crow Lake metavolcanic–metasedimentary belt have been dated by U–Pb analysis of zircons.The Sioux Lookout area is composed of a sequence of generally fault-bounded metavolcanic and metasedimentary belts. The age of a felsic tuff in the Central volcanic belt is [Formula: see text]. This is possibly the youngest sequence in the area.The Savant Lake volcanic belt comprises the Jutten volcanic unit at its base separated by an angular unconformity from the Handy Lake volcanic sequence. The age of a dacitic tuff near the base of the Handy Lake volcanic sequence is [Formula: see text].The South Sturgeon Lake volcanic belt is composed of four volcanic cycles. The age of a felsic tuff from the top of the uppermost cycle is [Formula: see text]. The felsic Beidelman Bay pluton and the mafic Pike Lake pluton, which both intruded the lower part of the sequence, give ages of [Formula: see text] and [Formula: see text], respectively. This establishes a minimum time span of [Formula: see text] for deposition of the sequence. This interval, along with the 27 Ma span between the ages of the Handy Lake sample and the volcanic sample from the South Sturgeon Lake area, suggests that the sequences were laid down by a series of discrete volcanic episodes.For samples subjected to multistage lead loss, the reliability of ages has been greatly enhanced by air abrasion of zircons. Several cases of suspected biasing of analyses by the air abrasion process have been encountered. It appears that this biasing problem can be overcome by selection and abrasion of low uranium grains that are free of imperfections.