Nitrate (NO
) pollution is a common phenomenon in karst underground rivers, which are important water sources in karst landscapes. For drinking water safety and environmental protection, it is ...crucial to accurately identify NO
sources and their migration and transformation processes in the Lihu Underground River. In this study, water samples of the Lihu Underground River in Guangxi were collected in May 2014, October 2014, January 2015, and July 2015, and water chemical and dual isotopic (δ
N-NO
and δ
O-NO
) approaches were used to evaluate the NO
characteristics and sources in the Lihu Underground River. The concentration of NO
in the Lihu Underground River ranged from 1.16 to 19.78 mg·L
, with an average of 9.30 mg·L
, which is more than 37% of the WHO standard (10 mg·L
). The concentrations of NO
in the wet season (May 2014 and July 2015) were slightly lower than those in the dry season (from October 2014 to January 2015) at most sampling sites due to dilution effects. The migration and transformation processes of NO
were analyzed by comparing the measured and calculated concentrations of NO
in the Lihu Underground River. In the dry season (from October 2014 to January 2015), the variation in NO
concentration upstream and midstream of the Lihu Underground River was affected by exogenous input and nitrification. From midstream to the outlet of Xiaolongdong, it is affected by self-purification factors, including physical processes, chemical processes, and biological processes. In the wet season (May 2014 and July 2015), the dilution and mixing effects were the main factors controlling the variation in NO
concentration in the Lihu Underground River. The contribution rates of potential NO
sources (incl. atmospheric precipitation (AP), NO
fertilizer (NF), NH
in fertilizer and rainfall (NFA), soil organic nitrogen (SON), and manure and sewage (M&S)) were quantitatively evaluated by using the IsoSource model. The results showed that in May 2014, the main sources of NO
were M&S and NF, with contribution rates of 46% and 41%, respectively. In October 2014, NO
sources were M&S with a contribution rate of 47%, followed by NFA with a contribution rate of 31%. In January 2015, NO
sources in groundwater were M&S, with a contribution rate of 53%, followed by NFA (34%). In July 2015, the main NO
sources were M&S and NF, whose contribution rates were 54% and 39%, respectively.
The second book in the new collection Karstology in Development Challenges in the Karst brings together the findings obtained in planning and construction of motorways in the Karst. More than 350 new ...caves were opened up in the final wave of construction. This was followed by studies on arranging karstic features for tourism and their management. We also selected studies on karstic ecology, in which we made use of biological and microbiological research. At the end there is a summary of everything we need to take into account in planning different encroachments in karstic areas.
Križna jama belongs to the aquifer between Bloke plateau, Cerknica polje and Lož polje. Due to underground hydraulic gradient from NE (Bloke plateau) toward SW (Cerknica and Lož polje) general water ...flow is oriented in this direction. This is also a direction of water flow in Križna jama. From this point of view, the general hydrological situation seems to be clear – waters that flow superficially on Bloke plateau sink there, reappear in Križna jama and Križna jama 2 and appear at the surface again at Cerknica polje. Such thinking prevailed from the earliest explorations but recently done studies (Kogovšek
Although flowstone deposition process depend on several factors, two main conditions are necessary for flowstone deposition: water has to be almost completely saturated with respect to Ca2+and ...partial pressure of CO2in the water has to be higher than partial pressure of CO2in the cave air. When such water comes through cracks in the cave wall, degassing of CO2occurs. Created disequilibrium in the water leads through several chemical reactions to the precipitation of calcium carbonate. If degassing of CO2is strong enough and the water is not entirely saturated with Ca2+, even at the beginning corrosive water
The first geological observation of the entrance part of Križna jama (up to the first lake) is closely related with palaeontological research in the cave. Therefore it was done by Austrian geologist ...Ferdinand von Hochstetter in 1881, who digged out more than 2,000 bones of cave bears at the end of 19thcentury. Milovanovič (1937, ex Pleničar, 1953) investigated liasic limestones in the SE periphery of Cerknica polje that is wider area of Križna jama. In 50-ies the wider area of Cerknica polje was investigated by geologist Pleničar (1953). The main purpose of his work was to define geological structure
From a hydrological point of view, active caves are a series of connected conduits which drain water through an aquifer. Water tends to choose the easiest way through the system but different ...geological and morphological barriers act as flow restrictions. The number and characteristics of restrictions depends on the particular speleogenetic environment, which is a function of geological, geomorphological, climatological and hydrological settings. Such a variety and heterogeneity of underground systems has presented a challenge for human understanding for many centuries. Access to many underground passages, theoretical knowledge and recent methods (modeling, water pressure-resistant dataloggers, precise sensors etc.) give us the opportunity to get better insight into the hydrodynamic aspect of caves. In our work we tried to approach underground hydrodynamics from both theoretical and practical points of view. We present some theoretical background of open surface and pressurized flow in underground rivers and present results of some possible scenarios. Moreover, two case studies from the Ljubljanica river basin are presented in more detail: the cave system between Planinsko polje and Ljubljansko barje, and the cave system between Bloško polje and Cerkniško polje. The approach and methodology in each case is somewhat different, as the aims were different at the beginning of exploration. However, they both deal with temporal and spatial hydrodynamics of underground waters. In the case of Bloško polje-Cerkniško polje system we also explain the feedback loop between hydrodynamics and Holocene speleogenesis.
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