Tracing the Relationship between Precipitation and River Water in the Northern Carpathians Base on the Evaluation of Water Isotope Data

Abstract

The aim of this study is to investigate the stable isotope composition of precipitation and river water from the northeastern part of Romania. For this study, we collected monthly samples (for variable periods of time) of precipitation from six stations, and river water from three stations, between March 2012 and December 2017. The precipitation in the area is sourced mainly from the Atlantic Ocean, and secondarily from the Black Sea, local recycling being important especially in summer. We found that the seasonal δ 18 O in precipitation is in agreement with the seasonal temperature variability, as shown by the significant correlation coefficient between the two variables (r = 0.77), which indicates that the temperature has an important role in the δ 18 O variability in precipitation water in this region. The local meteoric water line in the northeastern part of Romania is defined by the equation δ 2 H = 7.80 × δ 18 O + 7.47, (r 2 = 0.99, n = 121). The results presented in this study emphasize that the δ 18 O (and δ 2 H) and d-excess variability are strongly influenced by temperature, precipitation and the prevailing large-scale atmospheric circulation. precipitation and river water could give further information on regional and global scale hydrological processes, thus enabling better planning for water usage in the context of future potential changes in the climate system [12].In order to better understand the dynamics of water in a given watershed using the stable isotopes of oxygen and hydrogen, a two-step approach is required: First, identification of the contribution of regional and local moisture sources to precipitation generation, and second, identification of links between stable isotopic composition and atmospheric and hydrologic processes affecting surface water [13].A remarkable number of studies which investigate the relationship between hydrogen and oxygen isotopes in precipitation and river water have been carried out in Europe [3,[13][14][15][16][17], and elsewhere in the world [2,4,12,[18][19][20], but currently, similar studies in the Eastern Carpathian Mountains, the main recharge area for rivers in Southeast Europe, are missing. To fill this gap in knowledge, we have designed a study aiming: i) To investigate the temporal and spatial variations of the stable isotope compositions of precipitation and river water from the northeastern part of Romania, in order to identify the impact of different local, regional and large-scale factors on the variability of oxygen and hydrogen isotopic composition using the available isotopic data set; ii) to define the local meteoric water line (LMWL) over the analyzed region; and iii) to investigate the relation between air moisture sources and the prevailing large-scale atmospheric circulation. In this study we provide the preliminary database of the oxygen and hydrogen isotopes in precipitation and river from the northeastern part of Romania which will improve our understanding regarding the temporal and spatial variations of the stable isotopic compositions...

Characteristics of Hydrogen and Oxygen Isotope Composition in Precipitation, Rivers, and Lakes in Wuhan and the Ecological Environmental Effects of Lakes

“…They are ideal indicators for studying water cycling and they have been widely used [14][15][16][17][18]. For example, Zanazzi et al [19] measured Utah Lake's water balance by using stable hydrogen and oxygen isotopes and found that the groundwater recharged by snow melting was the primary source of river water in the Utah Valley; Nagavciuc et al [20] tracked the relationship between precipitation and river water in the northern Carpathian Mountains based on water isotope data and found that temperature had a significant impact on the change of δD in the precipitation; Li et al [21] analyzed the hydrogen and oxygen isotopes of urban rivers and believed that the comprehensive influence of climate and human factors was an essential reason for the changes in isotopic characteristics of urban rivers; Qu et al [22] revealed the isotopic characteristics and water source of the Hemuqiao Basin in the small watershed of the lower Yangtze River by analyzing the Stable nuclide composition of precipitation.…”