Ammonium uptake in alpine streams in the High Tatra Mountains (Slovakia)

Uptake of NH _inf4 ^sup+ -N by streambed biota of mountain brooks was studied in the alpine zone of the High Tatra Mountains. Experiments were performed involving in situ dosing of ammonium directly to the acidified stream and incubations of ammonium and streambed bryophytes in enclosures within a range of pH from 4.45 to 8.10.NH _inf4 ^sup+ -N uptake length decreased with decreasing stream discharge, while comparable values of discharge-normalized uptake lengths were found during two in situ experiments.Maximum uptake rates of NH _inf4 ^sup+ -N obtained during the incubation of bryophytes (6 to 11 mg m^–2 h^–1) were comparable with results of two in situ experiments (8 and 12 mg m^–2 h^–1). The average NH _inf4 ^sup+ -N uptake rates observed during incubations lasting 3 to 5 hours (4.3 mg m^–2 h^–1) were not related to the pH of stream water. Nitrification of about 50% of the NH _inf4 ^sup+ -N added was observed in non-acidified streams, but was negligible in acidified streams. Significant photoinhibition of nitrification was observed in non-acidified streams during enclosure experiments.     

Patterns of prevalence among bacterial communities of alpine accentors (Prunella collaris) in the Tatra Mountains

Patterns of prevalence in communities of bacteria in free-living adult, juvenile, and feces of alpine accentors (Prunella collaris) were studied in the West Carpathian Mountains, Slovakia, in 2002–2003. A total of 27 species of bacteria belonging to 13 different genera were identified in cloacal and pharyngeal swabs taken from captured birds (n = 30) and/or in feces (n = 171). Forty-six percent of adult males, 75% of adult females, and 82% of juveniles sampled tested positive for one or more types of bacterium. A close association was found between the genera Hafnia, Bifidobacterium, and Pseudomonas. The prevalence of bacteria in accentors was found to vary among seasons and between years but was not, in general, site-specific. Enterococcus and Escherichia (and possibly Hafnia and Serratia) were most prevalent in summer, whereas Bacillus, Klebsiella, Pantoea, Pseudomonas, Staphylococcus, and Yersinia occurred more often during other seasons. Evidence is presented that anthropogenic food obtained as refuse probably has a significant effect on the gut flora of birds frequenting areas of high human use.     

Water temperatures and ice cover in lakes of the Tatra Mountains

In 2000 and 2001, miniature thermistors with integrated data loggers were employed to measure lake surface water temperatures (LSWTs) and temperature profiles in high-altitude mountain lakes lying between 1580 and 2145 m a.s.l. on both the Slovak and Polish sides of the Tatra Mountains. This allowed the annual cycle of water temperatures and ice cover in these lakes to be described quantitatively, and their dependence on lake altitude above sea level to be investigated. LSWTs in the Tatra Mountains are found to decrease approximately linearly with increasing altitude from late spring to autumn. LSWT in summer can be modelled well in terms of exponentially smoothed ambient air temperature. Although the timing of ice-off is dependent on altitude, the timing of ice-on is not; the dependence of the duration of ice cover on altitude is therefore wholly due to the altitudinal dependence of the timing of ice-off. The temperature profile measurements allow quantitative characterization of summer and winter stagnation, and spring and autumn turnover.     

Vascular plant diversity and climate change in the alpine zone of the Snowy Mountains,Australia

This study examines vascular plant species richness along an altitudinal gradient in alpine Australia. Vascular plant composition and soil temperature records were obtained for five summits (from 1729 m to 2114 m a.s.l.) using sampling protocols from the Global Observation Research Initiative in Alpine Environments program. Species richness was examined against altitude, aspect and climatic variables at different spatial scales (10 × 10 cm quadrats, 1 m² quadrats, clusters of 4 * 1 m² quadrats, for the summit area above a line 5 m altitudinally below the summit (the −5 m isoline), for the extended summit down to the −10 m isoline). About 75 taxa (70 species, 5 graminoid genera) were recorded, 9 of which are endemic to the small alpine area of ∼100 km². There were significant linear relationships between species richness and altitude and climatic variables for the top to −5 isolines on the summits. However, there was no consistent pattern for species richness at other spatial scales, altitude, aspect or climatic variables. The proportion of species for the whole summits with localised distributions (local endemics) increased with altitude. Predicted increasing temperatures and reduced snowcover is likely to result in an increase in species richness as shrubs, herbs and introduced weeds become more common at higher altitude. Because Australian alpine areas occur in narrow altitudinal bands with no nival zone, there are no higher altitudinal refuges available for alpine species. Therefore many of these species are likely to be at risk of extinction from climate change.     

Numerical syntaxonomy of the tall-forb and tall-grass communities in the Tatra Mountains

The tall-forb and tall-grass subalpine and alpine vegetation belonging to the Mulgedio-Aconitetea from the Tatra Mountains was subjected to reclassification with Complete Linkage Clustering. The communities are classified into 3 alliances: Adenostylion, Calamagrostion villosae and Trisetion fusci. It was concluded that the orders Adenostyletalia and Calamagrostietalia villosae should be fused into one unit. Synecological relations of the communities was clarified using a series of Detrended Correspondence Analyses.Abbreviations CLC = Complete Linkage Clustering - DCA = Detrended Correspondence Analysis     

Chemical characteristics of lakes in the High Tatra Mountains,Slovakia

The chemistry of 53 lakes at various stages of acidification and inhabited (at the presence and/or in the past) by pelagic Crustacea was studied in September 1984. Ten of these lakes were investigated in detail biannually (July and October 1987–1990). The July results reflect the influence of snowmelt and were compared with the October ones. The most important anion was sulphate with the average values of 98 and 104 μeq 1^-1 in 1984 and 1987–1990, respectively. High concentrations of nitrate (21–56 μeq 1^-1) were observed in lakes above the treeline. Mean relative composition of cations does not differ between July and October; small changes are in the mean relative composition of anions. Acidification of lakes, expressed as a decrease in alkalinity, is 100 μeq l^-1, and is equal to the increase in the sum of sulphate and nitrate. The values of total phosphorus and COD are the lowest in the range of pH 5–6.5. Alkalinity, sulphate, nitrate and pH do not show any trend with time over the last ten years.     

Factors governing nutrient status of mountain lakes in the Tatra Mountains

1. Nutrient and chlorophyll a levels, and bacterial numbers of 84 glacial lakes in the Tatra Mountains (Slovakia and Poland, Central Europe) were determined to assess the impact of catchment vegetation and water acidity on lake trophic status. 2. Catchment vegetation was the crucial factor governing nutrient content of lakes. 3. Concentrations of organic carbon, organic nitrogen, and chlorophyll a, and bacterial numbers were tightly correlated with total phosphorus (TP) content. Their levels were the highest in forest lakes, then decreased in alpine lakes with decreasing amount of catchment vegetation and soil cover, and were the lowest in lakes situated in bare rocks. 4. The above pattern was further modified by lake water acidity. Concentrations of TP, organic carbon, and chlorophyll a were lower in alpine lakes with pH between 5 and 6 than in more or less acid alpine lakes. Zooplankton was absent in all alpine lakes with pH between 5 and 6. 5. Nitrate concentrations followed an inverse trend to TP; lowest values were in forest lakes, then increased with decreasing amount of catchment soils and vegetation. Within the lakes of the same type of catchment vegetation, nitrate concentrations were negatively correlated to TP. N‐saturation of catchment areas and lake primary production were dominant processes controlling nitrate levels in lakes and nitrate contribution to lake acidification.     

Radiometric dating of sediment records from mountain lakes in the Tatra Mountains

Sediment cores from nine different lakes in the Tatra Mountains, collected as part of the EU funded AL:PE, MOLAR and EMERGE projects investigating natural environmental records stored in remote mountain lake sediment sequences, were dated radiometrically by ²¹⁰Pb and ¹³⁷Cs. At five sites, D?ugi Staw G?sienicowy and Zielony Staw G?sienicowy on the Polish side of the Tatra Mountains and Starolesnianske pleso, Ni?né Terianske pleso, and L’adové pleso on the Slovak side of the Tatra Mountains, the cores were sectioned at close intervals and analysed in detail to produce a high resolution chronology. For the remaining four sites, Zmarzly Staw G?sienicowy (Poland), and Vel’ké Hincovo pleso, Vy?né Temnosmre?inské pleso, Vy?né Wahlenbergovo pleso (Slovakia), it was sufficient to establish a low resolution sketch chronology and only a few samples were analysed from each core. At L’adové pleso, multiple cores were collected in order to establish spatial distribution of sediments over the bed of the lake. Cores from all sites had good records of the fallout radionuclides from which it was possible to construct reliable chronologies of the recent sediments.     

Acidification of small mountain lakes in the High Tatra Mountains,Poland

A hydrochemical investigation was carried out on eight small High Tatra mountain lakes (Poland). When comparing recent data with those from the period 1935–1965, a constant process of acidification of the lakes is found. The average pH of precipitation is 4.8 in the study area, but the lakes are in two stages of acidification: weak (pH 6.0–6.5) and intermediate (pH 5.5–5.8). The differences are due to differences in water sources.     

Algal flora of lakes in the High Tatra Mountains (Slovakia)

Eighty seven from a total of 120 lakes in the Slovak part of the High Tatra Mts. have been visited since 1982. Their summer phytoplankton and algae growing on stones were collected, identified and documented. Some species that are interesting, rare, or not previously known in Slovakia have been found: Clastidium setigerum, Colacium calvum, Chroococcus subnudus, Chr. quaternarius, Coelastrum printzii, Coenocystis quadriguloides, Oocystis naegelii, Scopulonema polonicum, Thelesphaera alpina, Trochiscia prescottii. The number of algal species, found in the open water of the lakes, decrease with altitude and increase with pH.     

Chemical composition of modern and pre-acidification sediments in the Tatra Mountain lakes

Concentrations of major nutrients (C, N, P) and acid soluble metals (Ca, Mg, K, Al, Fe, Mn, Pb, and Zn) were determined in modern (0–1 cm) and pre-acidification (5–10 cm) sediment layers collected from 37 alpine and 3 forest lakes in the Tatra Mountains (Slovakia, Poland) in 1996–1998. Sediment composition reflected catchment characteristics and productivity of lakes. In the sediments of alpine lakes, C and N concentrations decreased and Mg increased with a decreasing proportion of vegetation and soil in the catchment. Decreasing Ca:Mg ratios in sediments along the vegetation gradient was inverse to that in water, and could be associated with different ratios of cations in water leachate from catchments and in solids which enter the lake due to soil erosion. Phosphorus concentrations increased with the proportion of moraine areas, with till soils rich in P. Concentrations of C, N, P, and Ca in sediments positively correlated to their concentrations in water. Sediment concentrations of Al and Al:Ca ratios increased with decreasing sediment and water pH. A negative correlation between water pH and concentrations of organic C in water and sediments indicated the important impact of organic acids on the acid status of the lakes exposed to higher terrestrial export of organic matter. Compared to the pre-acidification period, the modern sediments had significantly higher Fe, Mn, Zn, Pb, and K, but lower Mg concentrations. The Zn and Pb enrichment was more evident in oligotrophic alpine lakes than in more productive forest lakes and was independent of lake water or sediment pH. Fe and Mn concentrations in the modern sediments were higher than in ambient soils and bedrock, while those in pre-acidification sediments were similar to contemporary soils and to the rock layer. The enrichment of the modern sediments with Fe and Mn thus probably resulted from both their redox recycling and ecosystem acidification.     

Chlorophyll-phosphorus relationship in acidified lakes of the High Tatra Mountains (Slovakia)

Concentrations of total phosphorus (TP) and chlorophyll a (CHLA) were measured in 28 lakes in the High Tatra Mountains (Slovakia) from 1983 to 1990. The relationship between log CHLA and log TP in the Tatra lakes is similar to relationships developed for lakes in other regions, but variation is higher. A part of this variation is caused by acidification of the lakes. In the lakes with pH between 4.9 and 6.3 the CHLA concentrations are often extremely low while TP concentrations decreased, but not as drastically.     

Epilithic diatoms of mountain lakes of the Tatra Mountains (Slovakia)

In the framework of the international project EMERGE, species composition of epilithic diatoms of 34 selected high mountain lakes of Slovak part of the Tatra Mountains were investigated. In all, 127 taxa of diatoms belonging to 26 genera were recorded. Comparison of the epilithic assemblages of the investigated lakes showed differences both in relative abundance and taxa present in the individual lakes. On the basis of species composition and relative abundance of epilithic diatoms using hierarchical cluster analysis, two main groups of lakes were created. The first group includes 4 lakes which can be classified as strongly acidified and 9 lakes which are acidified or threatened by acidification. In this group, acidophilous species such as Achnanthes helvetica, A. marginulata, Aulacoseira distans and Tabellaria flocculosa prevailed. The second group includes 19 non-acidified lakes. The most common diatoms in these lakes were Achnanthes minutissima, A. helvetica, Cymbella minuta and Denticula tenuis which occur practically in all these lakes but with different abundances. The division of lakes due to their diatom species composition mostly confirmed the status of these lakes as judged from their water chemistry.     

Methanogenic activities in alpine soils

Uncontrolled microbial methane production is playing an important role in global warming. In the present study, we showed that water content and incubation temperature increase the potential for methane formation in the two alpine soils under investigation. Beside these factors, the grazing of cows and thus the amendment of methanogenic microorganisms by cattle dung is the most important factor determining the potential of methane production in those soils.     

Diet selection by European hares (Lepus europaeus) in the alpine zone of the Snowy Mountains, Australia

European hares (Lepus europaeus) are grazers and open grassland specialists that are replaced in mountain areas of their natural range in the northern hemisphere by browsing/intermediate feeding mountain hares (Lepus timidus), but in their introduced range in the southern hemisphere, occupy the alpine zone. We used micro-histological identification of plant fragments and germination of seeds in faecal pellets of L. europaeus from the Snowy Mountains, Australia, to determine diet. We asked whether diet shifted and/or diet breadth expanded in response to seasonally reduced food availability, particularly during winter. If so, did the constraints of food availability in the alpine zone lead to the diet mirroring that of L. timidus in its native alpine habitat. The diet of L. europaeus was dominated by grasses, herbs and shrubs. The main diet items in summer were grasses (70 %) and herbs (28 %). Grasses declined in the diet between summer and autumn when herbs increased to co-dominance, with a further change after establishment of the winter snowpack to a greater preponderance of shrubs (43 % compared with a maximum of 3 % in snow-free months). L. europaeus selected a wider range of plants in winter (59 species compared with 39 in summer) and diet was significantly more variable in winter than in autumn or summer (and in autumn than summer). We concluded that the persistence of L. europaeus in alpine areas of the southern hemisphere is testament to their ability to expand their dietary breadth to occupy mountain climatic zones normally occupied by L. timidus.     

A reconstruction of flood events using scarred trees in the Tatra Mountains, Poland

In this paper we reconstructed flood events in a small mountain stream (6.6 km long, elevation 1100–1950 m a.s.l.) in the Dolina Waksmundzka Valley in the Tatra Mountains in the Western Carpathians. This reconstruction was based on cross-dated flood scars found in Norway spruce trees growing along stream banks. The scars were most likely formed by woody debris and stones transported during flood events. Reconstructed flood years were then compared with climatic records collected at the nearest meteorological station.Fifty-eight scars were cross-dated indicating 17 years with flood events in the period between 1928 and 2005. The large number of reconstructed flood events proves that the Potok Waksmundzki stream discharge can be highly variable. The high mid-summer rainfall (approximately 300 mm or more per month) peaks in June, July, August and this period coincides with some of the flood scar formation. The high winter and spring precipitation (December–May) does not seem to induce floods. The rate of snow melting seems to be more important. The highest number of scars (33%) was formed in dormant season of 1957/1958. In April and May 1958 there was an unusually large difference between mean monthly temperatures, the highest recorded in the twentieth century. This probably led to an abnormally rapid snow melt. No one single climatic factor can be held responsible for all flood events. Intensive mid-summer rainfall as well as rapid snow melting may induce floods in the Dolina Waksmundzka Valley. Cross-dated scars have enabled past flood events to be detected, which are otherwise invisible from climatic data alone.     

Bacterial composition of soils of the Lake Wellman area, Darwin Mountains, Antarctica

The aim of this study was to examine the bacterial composition of high latitude soils from the Darwin–Hatherton glacier region of Antarctica. Four soil pits on each of four glacial drift sheets were sampled for chemical and microbial analyses. The four drifts—Hatherton, Britannia, Danum, and Isca—ranged, respectively, from early Holocene (10 ky) to mid-Quaternary (ca 900 ky). Numbers of culturable bacteria were low, with highest levels detected in soils from the younger Hatherton drift. DNA was extracted and 16S rRNA gene clone libraries prepared from samples below the desert pavement for each of the four drift sheets. Between 31 and 262 clones were analysed from each of the Hatherton, Britannia, and Danum drifts. Bacterial sequences were dominated by members of the phyla Deinococcus-Thermus, Actinobacteria, and Bacteroidetes. Culturable bacteria, including some that clustered with soil clones (e.g., members of the genera Arthrobacter, Adhaeribacter, and Pontibacter), belonged to Actinobacteria and Bacteroidetes. The isolated bacteria are ideal model organisms for genomic and phenotypic investigations of those attributes that allow bacteria to survive and/or grow in Antarctic soils because they have close relatives that are not tolerant of these conditions.     

Climate sensitivity of high- and low-elevation Larix decidua MXD chronologies from the Tatra Mountains

Maximum latewood density (MXD) measurements from high-elevation/-latitude sites are an important proxy for summer temperature reconstructions. Here, we present 201 MXD series from living larch (Larix decidua Mill.) trees that were growing at around 850 and 1450 m a.s.l. in the Slovakian Tatra Mountains, together with 56 MXD series from historical timbers of the same species and region. We explore the climate signal at the high- and low-elevation sites and assess the effects of varying temperature and precipitation regimes on MXD formation. Ranging from spring temperature to summer precipitation, the elevation-specific climate sensitivity suggests that the MXD measurements from living and relict sources should not be merged for paleoclimatic studies. This finding emphasizes the challenge of attributing a predominant climate factor that controls wood formation across a wide range of historical constructions. A better understanding of the ‘true’ climate signal requires more samples during the period of overlap between the living and historical trees.     

Hydrological processes in small catchments of mountain headwater lakes: The Tatra Mountains

This study evaluates runoff and different methods for the estimation of water balance and runoff genesis in four small alpine catchments, which lie outside the standard network of hydrological and climate networks. These test catchments, whose size ranges between 2.3 and 110 ha, are located above the timberline at elevations between 1,784 and 2,380 m. Their land surfaces consist of lakes, rock formations, debris deposits, and alpine meadows. Hydrological data were collected for the water year 2001. The catchments were instrumented by three automatic weather stations recording global and net solar radiation, air temperature, humidity, precipitation, and soil temperature. Lake water levels were registered with staff gauges and runoff evaluated from water storage calculations. Runoff genesis was investigated by means of chemical tracers (Rhodamine WT and Lithium chloride). Hydrological process estimations were made using standard methods including: the input of precipitation and snowmelt, both potential and actual evaporation, which was estimated by the approaches of Hamon, Priestley-Taylor, Penman and Grindley, and runoff calculated from the lake storage, were compared with results of the conceptual hydrological Brook90 model. The empirical results show that hydrological processes are governed by the temperature-dependent regime of high mountain snowmelt. However, the major differences in water yield and runoff genesis between watersheds were due to differences in the morphologies of the lakes and their basins, the soilvegetation complex, and runoff routing. Evaluating approaches to estimation, Penman’s combination of both aerodynamic and energy balance method provides the best fit to observed data with observed evapotranspiration being 78 to 99% of the potential calculated. The deterministic Brook90 model is effective for precipitation-runoff genesis studies in small headwater catchments. In the L’adové pleso basin predicted and observed water yield show close correlation. The annual sum of actual evapotranspiration calculated by BROOK90 (352 mm) corresponds closely to that estimated by the approach of Penman (386 mm).