Abundance and spatial dynamics of bacterioplankton in the Seven Rila Lakes,Bulgaria

In the high mountain oligotrophic Seven Rila Lakes (2 095–2 535 m a.s.l.) bacterial abundance was recorded in July and September 2006. In July, bacterial abundance (average (3.32±2.5)×105 cell/ml) in the lakes correlated negatively with elevation, while in September (average (26.39±7.1)×105 cell/ml) this pattern was altered and the greatest abundance of bacteria occurred at the highest ((39.05±1.5)×105 cell/ml) and the lowest ((30.63±6.0)×105 cell/ml) elevated lakes. Regression analyses suggested that the principal factor controlling bacterial abundance, in both July and September, was inorganic nitrogen (NO3-N and NH4-N; R2=0.70, P<0.05). Other major regulating factors were temperature (R2=0.66, P<0.03) in July and filter-feeding zooplankton (R2=0.95, P<0.01) in September. All factors, except NO3-N, had a positive effect on bacterial abundance.

Morphology and biology of Cyclops scutifer Sars, 1863 in high mountain lakes of East Siberia (including Lake Amut)

Data on zooplankton from 13 high-mountain lakes of East Siberia have shown that the Holarctic copepod Cyclops scutifer Sars,1863 dominates among crustaceans.In July,its abundance comprised 64%-98%of the total plankton fauna in the pelagial of these lakes,approximately 30%in the littoral zone and10%in small northern thermokarst lakes.Biometric measurements and morphological descriptions based on scanning microscope images are supplemented by the data on its geographic distribution and phenology.

Can a dam type of an alpine lake be derived from lake geometry?A negative result

Glacial lake outburst floods(GLOFs)represent one of the most serious hazard and risk in deglaciating high mountain regions worldwide and the need for GLOF hazard and risk assessment is apparent.As a consequence,numerous region-and nation-wide GLOF assessment studies have been published recently.These studies cover large areas and consider hundreds to thousands of lakes,prioritizing the hazard posed by them.Clearly,certain simplification is required for executing such studies,often resulting in neglecting qualitative characteristics which would need manual assignment.Different lake dam types(e.g.,bedrock-dammed,moraine-dammed)are often not distinguished,despite they control GLOF mechanism(dam overtopping/dam breach)and thus GLOF magnitude.In this study,we explore the potential of easily measurable quantitative characteristics and four ratios to approximate the lake dam type.Our dataset of 851 lakes of the Cordillera Blanca suggests that while variances and means of these characteristics of individual lake types differ significantly(F-test,t-test),value distribution of different geometrical properties can’t be used for the originally proposed purpose along the spectra.The only promising results are obtained for extreme values(selected bins)of the ratios.For instance,the low width to length ratio indicates likely morainedammed lake while the high value of ratio indicating round-shape of the lake indicates increased likelihood of bedrock-dammed lake.Overall,we report a negative result of our experiment since there are negligible differences of relative frequencies in most of the bins along the spectra.

Application of Sediment Traps in Global Change Research in Mountain Lakes

Representativity of biota in the biosphere also have similar significance in the lithosphere after their death. Recently, taphonomic representation of biota in the lithosphere has been widely used for minimizing the biases in palaeo-environmental reconstructions including global climate change. In September 2001, a sediment trap was installed at the central area of the Loch Coire Fionnaraich （LCFR）, a small, oligotrophic mountain loch in northwest Scotland for a taphonomic study of cladoceran zooplankton. The trap was emptied on a seasonal basis, where an average 0.14 g dry material was recovered in each season, January, May and August 2002 respectively. A sediment core was also taken from near the sediment trap location. The top 0.5 cm section, the ＇core＇ was used for a comparative study with the trap sediment samples. The planktonic Cladocera consisted of Bosmina coregoni and appeared to have excellent preservation in the trap assemblages. Moreover, some common littoral Cladocera such as Alonella excisa and Aloha guttata appear to be less well preserved in the fossil assemblages. Large littoral taxa such as Eurycercus lamellatus and Aloha quadrangularis were rare in the trap but relatively common and well preserved in the sediment-water interface. It is suggested that taphonomic processes play a dominant role on deposition of fossil remains of Cladocera and caution should be taken while inferring the past environmental changes whilst using fossil assemblages recovered from the lake centre as a representation of the entire cladoceran community in the lake.

Conditions of spatiotemporal variability of the thickness of the ice cover on lakes in the Tatra Mountains

This research aimed to identify the impact of local climatic and topographic conditions on the formation and development of the ice cover in highmountain lakes and the representativeness assessment of periodic point measurements of the ice cover thickness by taking into consideration the role of the avalanches on the icing of the lakes.Field works included measurement of the ice and snow cover thickness of seven lakes situated in the Tatra Mountains(UNESCO biosphere reserve)at the beginning and the end of the 2017/2018 winter season.In addition,morphometric,topographic and daily meteorological data of lakes from local IMGW(Polish Institute of Meteorology and Water Management)stations and satellite images were used.The obtained results enabled us to quantify the impact of the winter eolian snow accumulation on the variation in ice thickness.This variation was ranging from several centimetres up to about 2 meters and had a tendency to increase during the winter season.The thickest ice covers occurred in the most shaded places in the direct vicinity of rock walls.The obtained results confirm a dominating role of the snow cover in the variation of the ice thickness within individual lakes.

Interannual and Seasonal Changes in the Ice Cover of Glacial Lakes in the Snowy Mountains of Australia

Seasonal ice cover is uncommon on Australian lakes. In the Snowy Mountains, there are five natural, seasonally ice-covered lakes including Lake Cootapatamba, the highest lake in Australia. Blue Lake is the only one of the five lakes with sufficient volume to be relatively independent of short-term changes in ambient temperature, and therefore is the lake most likely to be of use in tracking long-term regional climate change. Ice forms on Blue Lake near the winter solstice and ice-breakup occurs from late September to November. Timing of breakup is related to spring temperature and, as such, mirrors the timing of general snow thaw in the mountains. The existence of historic photographs taken of the lake at about the time of ice breakup allows for the possibility of reconstructing a history of alpine climate and in 1905 ice breakup was probably as late as mid-December.

Carnivals between Cangshan Mountain and Erhai Lake

THE Bai people are China’s 15th largest ethnic minority.They live mainly in Yunnan Province,specifically in Dali Bai Autonomous Prefecture,and some in Guizhou and Hunan provinces.Dali is where the Bai people’s ethnic roots are.From the 23rd to 25th day of the fourth lunar month every year,Bai people in Dali pray for

Eden in the Xinjiang Mountains

Nature's greatest splendors are often secreted in the remotest of spots. This is certainly true of Kanas Lake, deep in the Altay Mountains of northern Xinjiang Uygur Autonomous Region. This area of sublime, and as yet unsullied, natural beauty is home to 2,000 people of the Tuwa ethnic minority. The ancestry of these herder-hunters is unclear. Certain anthropologists believe that they are descended from Genghis Khan's "Mongol hordes" that swept through on their 13th century rampage of Central Asia and Europe. Others argue that they are the posterity of Siberian migrants, and cousins to the Tuvan people of Russia.

Newt life after fish introduction： extirpation of paedomorphosis in a mountain fish lake and newt use of satellite pools

Fish introduction is one of the main causes of amphibian decline worldwide. It affects particularly rare aquatic phenotypes such as paedomorphs, which retain gills during the adult stage. In this context, we determined whether small wetlands, such as pools surrounding fished and fishless lakes, could sustain paedomorphic and metamorphic newts. To this end, we surveyed lakes known historically to sustain Alpine newts Ichthyosaura alpestris as well as 35 nearby pools. On the basis of the published records, the only known population exhibiting paedomorphosis in the Swiss AIps was found to be extirpated by salmonid introductions. However, the metamorphs persisted in per- ipheral pools, paedomorphosis was discovered at a new locality, and overwintering larvae were still present in one of the lakes. These results show the importance of conserving varied aquatic habitats such as pools in mountainous environments where the main resources can become un- suitable for amphibians because of fish introductions. Pools may also function as reservoirs in maintaining newt populations until programs to remove fish from lakes can be carried out. It is not known if paedomorphs could reappear after fish removal. However, the combined resilience of am- phibians after fish removal and the genetic basis for paedomorphosis highlighted in other taxa by previous studies suggest that there is the potential to maintain this intraspecific case of diversity even after its disappearance.