Isotopic composition of precipitation provides an insight into the origin of water vapour, the conditions obtaining during condensation and precipitation. Thus, the spatial variance of oxygen and hydrogen stable isotope composition (?p) and d-excess of precipitation was explored across the Iberian Peninsula for October 2002-September 2003 with 24 Global Network of Isotopes in Precipitation (GNIP) monitoring stations, and for October 2004-June 2006, in which 13 GNIP stations were merged with 21 monitoring stations from a regional network in NW Iberia. Spatial autocorrelation structure of monthly- and amount weighted seasonal/annual mean ?p values was modelled and two isoscapes were derived for hydrogen- and oxygen precipitation stable isotopes with regression kriging. Using, only the GNIP sampling network, no spatial autocorrelation structure of ?p could have been determined due to the scarcity of the network. However, in the case of the merged GNIP- and NW dataset, for ?p a ~70 and ~500 km, and for d-excess, a ~440 km spatial sampling range was documented. The comparison with the regional subset of one of the most widely used global models for precipitation stable isotopes suggests, that the current regional model provides a higher predictive power. The modeled isoscapes could provide input values for hydrogeological studies in areas of the Iberian Peninsula where no measured isotope data exist.
COBISS.SI-ID: 33164071
The paper describes spatial and temporal variations in extended stable isotope datasets of hydrogen and oxygen (?2H and ?18O) in the Sava River water that were used to estimate the mean residence time (MRT) of stream water using an exponential flow model. The re-examining MRT was (2 years in the Slovenian part of the Sava River and was in a good agreement with previous estimates and with the MRT estimated in the Sava River at Ostružnica near Belgrade, Serbia. The spatial distribution of ?18O in precipitation over the Sava River Basin (SRB) was mapped based on the long-term weighted mean annual ?18O values and established relationship with various geographical controls (latitude, longitude and altitude). The modelled ?18O values in precipitation agree with the measured values in the surface river water at different locations indicating that the spatial variation in the isotopic composition of precipitation is the dominant factor controlling surface water isotope ratios over the SRB.
COBISS.SI-ID: 31599911
The review paper presents a historical review of research activities in the field of isotope composition of precipitation in Slovenia. The first investigations of oxygen and hydrogen isotope composition and the tritium activity in precipitation over Slovenia were performed in the frame of tracer experiments conducted in the period 1972–1975 in the Ljubljanica River drainage basin. The first regular and systematic monitoring of isotope composition of precipitation only began in 1981 in Ljubljana but has been extended during the last 35 years to 30 different locations countrywide. We collected information about sampling, analytical methods, available data and their evaluation including calculations of local meteoric water lines. Based on the data, we identify gaps in the research and make recommendations for future monitoring in the frame of the Slovenian Network of Isotopes in Precipitation (SLONIP). The paper is the basis for future isotope in precipitation investigations in Slovenia and for co-operation with Hungarian colleagues in the frame of this project.
COBISS.SI-ID: 2547541
In this study we analysed trace elements (Li, B, Al, Ti, Mn, Fe, Co, Ni, Cu, Zn, As, Rb, Y, Mo, Cs, Ba, Eu, Tl, Pb, U), stable isotopes (?34SSO4, ?18O, ?2H), tritium (3H) and dissolved gases (CO2, CH4, N2, ?13CCH4, ?13CCO2) in groundwater from Pliocene and Triassic aquifers in the Velenje basin to determine hydrogeochemical processes influencing water quality. In addition to groundwater also isotope composition of precipitation was investigated. The ?18O and ?2H values of all groundwater samples plot along the global meteoric water line (MWL) and local MWLs within the range of local modern precipitation, indicating they are meteoric in origin with limited evaporation and/or geochemical processes that modify the stable isotope composition of water. The lower ?18O and ?2H values correspond to older groundwater with longer residence times and were observed in the Pliocene aquifer. The applied research highlights the use of different stable isotopes which are ideal tracers for investigating processes occurring in sedimentary coal basin not just on the local level, but also on the global level.
COBISS.SI-ID: 32819751
We present the calibration of a speleothem ?18O record from Postojna Cave (Slovenia) with the regional record of ?18O composition of precipitation during the last decades. Using local meteorological data and a regional ?18O record of precipitation, we developed a model that reproduces the cave drip water ?18O signal measured during a two-year period. The model suggests that the average water mixing and transit time in the studied aquifer is 11 months. Additionally, we used an ion microprobe - SIMS analysis to study the ?18O record of the top 500 µm of a speleothem from the studied cave galle-ry. According to U–Th dates and 14C analyses, the uppermost section of the speleothem was formed during the last decades. The ?18O record of the top 500 µm of the speleothem has a significant correlation (r2=0.64; p-value (0.001) with the modelled ?18O record of cave drip water. Therefore, we confirm that the top 500 µm of the speleothem grew between the years 1984 and 2003 and that the speleothem accurately recorded the variability of the ?18O values of regional precipitation filtered by the aquifer. We show that the recorded speleothem ?18O signal is not seasonally biased and that the hydrological dynamics described during monitoring period were stationary during recent decades. This research demonstrates that speleothems with growth rates (50 µm/yr can also be used for calibration studies. Additionally, we show that the fit of measured and modelled proxy data can be used to achieve annually resolved chronologies in speleothems that were not actively growing at the time of collection and/or that do not record annual laminae.
COBISS.SI-ID: 31166503