The snow line for the same precipitation event in alpine valleys can vary greatly from valley to valley, even when the valleys are close together. Often this is not due to a difference in air mass, ...but to a different interaction of topography and topography-related meteorological conditions. By knowing the causes of a lowered snow line, we can better understand the differences in snow cover in alpine valleys at the same elevation over short distances or the differences in snow cover between alpine valleys and areas outside the valleys. As different types of lowered snow line respond differently to climate change, we can also understand future changes in snow conditions in alpine valleys. To better understand the process, we observed the temperature conditions during winter precipitation events on the territory of Eastern Julian Alps (Slovenia) over a period of two years, focusing on the height of the zero isotherm. Depending on atmospheric conditions, especially changes in the temperature profile and precipitation intensity during precipitation events, five causes of lowered snow line have been identified. These types can occur individually, but during multi-day snowfall events they occur frequently or in combination.
Spring water chemistry and carbon cycling in our study mainly depend on geological composition of the aquifer. The investigated Alpine springs in Slovenia represent waters strongly influenced by ...chemical weathering of Mesozoic limestone and dolomite, only one spring was located in Permo-Carboniferous shales. The carbon isotopic composition of dissolved inorganic carbon (DIC) and suspended organic carbon (POC) as well as major solute concentrations yielded insights into the origin of carbon in Alpine spring waters. The major solute composition was dominated by carbonic acid dissolution of calcite. Waters were generally close to saturation with respect to calcite, and dissolved CO2 was up to fortyfold supersaturated relative to the atmosphere. δ13C of DIC indicates the portion of soil CO2 contributed in water and is related with soil thickness of infiltrating water in aquifer and could be therefore used as a tool for vulnerability assessment. The δ13C of DIC ranged from −15.8‰ to −1.5‰ and indicated less and more vulnerable aquifers. Mass balances of carbon for spring waters draining carbonate rocks suggest that carbonate dissolution contributes from approximately 49% to 86% and degradation of organic matter from 13.7% to 51.4%, depending on spring and its relation with rock type, soil environment, and geomorphic position. Stable oxygen isotope composition of water (δ18OH2O), and tritium values range from −12.2 to −9.3‰ and from 6.4 to 9.8 TU, respectively and indicate recharge from modern precipitation. According to active decay of tritium and tritium in modern precipitation the age of spring waters are estimated to be about 2.6years for springs located in Julian Alps, about 5years for springs located in Karavanke and about 5years for springs located in Kamniško–Savinjske Alps.
► In this study we examine water chemistry and carbon cycling of Alpine springs. ► The major solute composition was dominated by dissolution of calcite. ► More negative δ13CDIC values indicated less vulnerable aquifers. ► Isotopic composition of oxygen indicates recharge from precipitation. ► The age of springs was estimated according to tritium up to 5years.
Based on our analysis of a large number of relevés of communities of moist rock crevices in western Slovenia (southern Julian Alps, northern part of the Trnovski Gozd Plateau) we described several ...new syntaxa with the endemic
. The most unique in terms of ecology is a hygrophytic chasmophytic community classified into the association
, which is, together with similar hygrophytic associations
and
associations
,
and the subassociation
temporarily classified into the alliance
and order
. Only the new association
is classified into the alliance
The elevational range of chasmophytic communities with
is 200 to 1460 m a.s.l. Species that most commonly accompany
in rock crevices include
,
subsp.
,
and moss
We present a geomorphological map on a scale of 1:15,000, with detailed sedimentological descriptions, and a general relative spatio-temporal depositional reconstruction of Quaternary sediments in ...the Planica-Tamar Valley (NW Slovenia). After the Last Glacial Maximum, the retreating Quaternary glacier deposited large amounts of glacial sediments. These were followed by Holocene sediments, which differ in their sedimentological characteristics, transport mechanisms, and morphology. These sediments are deposited as sedimentary bodies with complex depositional geometries. They form areas of active, partly active, and inactive sedimentation in response to local/regional climate and bedrock geology. Previous research of the valley was mainly focused on bedrock mapping, while almost completely neglecting Quaternary deposits. This work is the first broader analysis of Quaternary sedimentary deposits in the research area, which offers an insight into the complex geomorphological and sedimentological processes, which shape the current mountainous landscape.
Results are presented of the first airborne LiDAR survey ever flown in Europe for the purpose of mapping the surface expression of earthquake‐prone faults. Detailed topographic images derived from ...LiDAR data of the Idrija and Ravne strike‐slip faults in NW Slovenia reveal geomorphological and structural features that shed light on the overall architecture and kinematic history of both fault systems. The 1998 MW = 5.6, and 2004 MW = 5.2 Ravne Fault earthquakes and the historically devastating 1511 M = 6.8 Idrija earthquake indicate that both systems pose a serious seismic hazard in the region. Because both fault systems occur within forested terrain, a tree removal algorithm was applied to the data; the resulting images reveal surface scarps and tectonic landforms in unprecedented detail. Importantly, two sites were discovered to be potentially suitable for fault trenching and palaeo‐seismological analysis. This study highlights the potential contribution of LiDAR surveying in both low‐relief valley terrain and high‐relief mountainous terrain to a regional seismic hazard assessment programme. Geoscientists working in other tectonically active regions of the world where earthquake‐prone faults are obscured by forest cover would also benefit from LiDAR maps that have been processed to remove the canopy return and reveal the forest floor topography.
We collected a sediment core from the 6th (6J) Triglav Lake, a remote mountain lake in NW Slovenia, and analysed it for 25 elements, using
k
0
-instrumental neutron activation analysis (
k
0
-INAA). ...For Hg, we used cold vapour atomic absorption spectrometry (CVAAS). Data were analysed using Principal Component Analysis (PCA). PCA indicated several distinct groups of elements and sediment core samples. Ca distribution was entirely different from all other sediment components. Ba, Br, Hg, Sb and Zn were associated with organic matter (OM), with Hg showing the strongest affinity to OM. As, Cr, Fe and U formed a group of redox-sensitive elements. Two events that occurred ca. 1915 and in the 1940s/1950s, were identified in the core. They were associated with increased inputs of allochthonous material into the lake, and significantly affected the stratigraphic distributions of all elements. Some trace elements, such as As, Hg and Zn, are probably effectively retained in the catchment, whereas Cr tends to be readily exported from the catchment. Atmospheric deposition affected not only elements of anthropogenic origin (As, Ba, Br, Hg, Sb, Zn and Cr) that started to increase after the 1970s, but also those of terrestrial origin (Ca, Fe, Na). Introduction of fish into the lake in 1991 and the subsequent increase in primary production, affected the distribution of Ca and elements that are redox-sensitive and/or associated with OM (As, Ba, Fe, Sb, U, Zn). Fe minerals in uppermost 6J sediments have a strong influence on the distribution of several trace elements. As and Zn closely tracked Fe, whereas Sb was likely released after oxidation. Climate change could also have enhanced inputs of elements from the catchment, but such changes were likely overwhelmed by the effects of increased eutrophication.
Increased eutrophication was recently observed in the 5th (5J) and 6th (6J) Triglav Lakes, two remote Slovenian mountain lakes. Sediment phosphorus (P) pools were analysed and potential external P ...sources affecting the lakes (atmospheric deposition, terrestrial export and nearby hut) evaluated, to assess the effects of internal and external changes on the lakes. A sequential extraction procedure was used to quantify five P fractions from the sediments: adsorbed (NH
4
Cl–P), redox-sensitive (BD–P), aluminium- (NaOH–P) and calcium- (HCl–P) bound, and refractory organic (Res–P) P. Total phosphorus (TP) contents in surface sediment of 5J and 6J were 1430 and 641 µg P g
−1
dry weight sediment (dw), respectively. TP varied with depth in 5J sediments, but displayed no discernible pattern, whereas it decreased steadily downcore in 6J. Contents of all P forms were distinctly higher in 5J than 6J, but their rank order and relative abundances were similar in the two lakes. Res–P was the most abundant P fraction, followed by HCl–P. Together, the two P forms accounted for nearly 80 and 90% of TP in 5J and 6J sediments, respectively. BD–P and NaOH–P were less abundant, with each fraction accounting for 3 to 9% of TP, whereas NH
4
Cl–P was least abundant. Atmospheric deposition and terrestrial export were substantial sources of P for the lakes. Delivery of the former was estimated to be at least 7.5 mg P m
−2
yr
−1
and the latter around 20 mg P m
−2
yr
−1
. We concluded that P was not retained in the catchment effectively, likely because of only slightly acidic soil pH (5.9), relatively low aluminium content and high organic matter content (53%) in soils, resulting in higher vulnerability of the studied lakes to eutrophication. The mountain hut could also be a significant source of P for the lakes. Each year, it could potentially contribute ~12 kg of soluble P to the environment, but the true impact of the hut on lake trophic status remains unclear.
We conducted a phytosociological analysis of more than 250 relevés in the Julian Alps and compared them with similar communities elsewhere in the Alps and in the Dinaric Alps to describe the ...following new syntaxa of alpine swards and heathlands from the alliance
(class
):
and
the new association
from the alliance
and two new syntaxa from the alliance
(class
):
and
. Many species that are rare, of conservation concern or protected in Slovenia occur in the newly described communities.
It is well known that small glaciers of mid latitudes and especially those located at low altitude respond suddenly to climate changes both on local and global scale. For this reason their monitoring ...as well as evaluation of their extension and volume is essential. We present a ground penetrating radar (GPR) dataset acquired on September 23 and 24, 2013 on the Triglav glacier to identify layers with different characteristics (snow,
firn
, ice, debris) within the glacier and to define the extension and volume of the actual ice. Computing integrated and interpolated 3D using the whole GPR dataset, we estimate that at the moment of data acquisition the ice area was 3800 m
2
and the ice volume 7400 m
3
. Its average thickness was 1.95 m while its maximum thickness was slightly more than 5 m. Here we compare the results with a previous GPR survey acquired in 2000. A critical review of the historical data to find the general trend and to forecast a possible evolution is also presented. Between 2000 and 2013, we observed relevant changes in the internal distribution of the different units (snow,
firn
, ice) and the ice volume reduced from about 35,000 m
3
to about 7400 m
3
. Such result can be achieved only using multiple GPR surveys, which allow not only to assess the volume occupied by a glacial body, but also to image its internal structure and the actual ice volume. In fact, by applying one of the widely used empirical volume-area relations to infer the geometrical parameters of the glacier, a relevant underestimation of ice-loss would be achieved.
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