Middle Of Lake Research Articles

Microbiology in the Field: Construction and Validation of a Portable Incubator for Real-Time Quantification of Coliforms and Other Bacteria.

Performing microbiological assays on environmental samples in field settings poses logistical challenges with respect to the availability of suitable equipment or the ability to get samples to the laboratory in a timely fashion. For example, the viability of some bacteria can decrease greatly between sampling and arrival to the laboratory for processing. We developed and constructed rugged, reliable, and cost-effective portable incubators that were used by 10 independent field teams to perform microbiological assays on surface water samples from lakes across Canada. Rigorous testing and validation of our incubators ensured that incubation conditions were consistent within and across all 10 field teams and 2 sampling years. Samples from all sites were processed in duplicate and bacterial counts were highly repeatable within and across sampling teams. Bacterial counts were also found to be statistically equivalent to counts obtained with standard laboratory techniques using a conventional incubator. Using this method, thermotolerant coliforms (TTCs) and Escherichia coli were quantified from 432 lakes, allowing comparison to both historical datasets that relied on TTCs and those following current guidelines that use E. coli counts. We found higher loads at the shoreline than the middle of lakes and different patterns between ecozones. E. coli was not frequently detected, but many lakes exceeded Canadian guideline values for activities such as swimming and some even exceeded the guideline value for secondary recreational activities such as boating. To the best of our knowledge, this is the largest bacteriological water quality assessment of freshwater lakes to date in terms of both spatial scale and the number of lakes sampled. Our incubator design can be easily adapted for a wide variety of researcher goals and represents a robust platform for field studies and other applications, including those in remote or low-resources settings.

Geochemical Information Indicating the Water Recharge to Lakes and Immovable Megadunes in the Badain Jaran Desert

Calc-sinters distributed in the middle of lakes and rhizoconcretions scattered at the slopes of sand dunes were observed during three explorations to the Badain Jaran Desert in the past two years. Wet sands were also found underneath the dry surface sand layers of about 20–50 cm in thickness. The geochemical parameters were measured on minerals and water samples collected from the Badain Jaran Desert and neighboring areas. The results show that the water system in the desert may be recharged from the groundwater originating from the precipitation of the Qilian Mountains and/or the Tibetan Plateau rather than the local rainfalls.

Monastères de la région du lac Blanc dans la Russie ancienne : îles au milieu des lacs, des marécages et des forêts

Monasteries in the Belozero Lake area in Ancient Russia : islands in the middle of lakes, marshes and forests. In many monasteries in Northern Russia, and particularly in the Belozero Lake area, folklore myth and Christian symbolism intertwine between water and the island. Such places also display aesthetical elements in the Byzantine tradition. These monasteries have been built either on islands, or in the middle of marshes or forests, where they stand as «islands». They're part of a specific monastic movement, as well as of a specific approach that thrives in the hesychast thought. The island then becomes a geographical as well as a spiritual concept. The island would seem to embody an ideal as opposed to fulfilling the desire of the monks. The monasteries of the Belozero Lake area have been cultural and spiritual centres ; sometimes, they were turned into prisons or places of exile, or even outposts in this northern region. Yet they are inextricably linked to the «startsy» across the Volga and consequently to the hesychast thought.

Studies on the modern sedimentary environment in Lake Hamana on the Pacific coast of Central Japan.

The study dealt primarily with some physicochemical properties of the bottom sediments of Lake Hamana and the behavior of phytoplankton in the lake water and the distribution of pollen grains and spores in the sediments. Lake Hamana is divided into three regions; 1) the northern half of the main lake with two adjacent small lakes, 2) the southern half of the main lake and 3) Lake Shonai. The former two regions of the main lake are divided by the bathymetrical lines of 4 to 8m across the middle of the lake. The lines were revealed to correspond roughly to the isovalue lines of Md φ of 4 to 8φ of the sediments, of ignition loss of 3 to 10%, of total carbons of 1.0 to 3.0%, and of total nitrogens of 0.1 to 0.3%. They also correspond to the isovalue lines of pollen grains and spores of 104 to 5×104 grains per g lyophilized sediment. Almost the same values were observed in the inner part of Lake Shonai as those in the northern half. All of the maximum values of these parameters were obtained in the northwestern part of the main lake and in the inner part of Lake Shonai. These values ranked with the higest levels found in the aquatic areas of Japan. In the present study, the sources of sediments supply to the stations in the main lake, where the accumulation is most evident, was examined using indicators, such as phytoplankton and pollen grains and spores. It was concluded that the main supply source is the river basin of the Miyakoda River. The organic substances and pollen grains and spores might mainly be transported through Lake Inasahosoe by the large amounts of flux of Miyakoda River and accumulated in the northern part of the main lake because of the lack of a vertical circulation due to water stratification, the tidal pressure at the bottom layer of the outer sea water and the existence of the topographical boundary around the middle of the main lake.