SOILS AND SEDIMENTS OF PROŠĆE LAKE CATCHMENT AS A POSSIBLE TERRIGENOUS INPUT IN THE LAKES SYSTEM TLA IN SEDIMENTI ZALEDJA PROŠČANSKEGA JEZERA KOT MOŽEN TERIGEN DOPRINOS V JEZERSKI SISTEM Anita PTIČEK SIROČIĆ 1 *, Stanislav KURAJICA 2 , Dragana DOGANČIĆ 1 & Nikolina FIŠTER 1 Abstract UDC 631.41:502.51(497.5Proščansko jezero) Anita Ptiček Siročić, Stanislav Kurajica, Dragana Dogančić & Nikolina Fišter: Soils and sediments of Prošće Lake catchment as a possible terrigenous input in the lakes system The Plitvice Lakes National Park is in the northwestern part of the Dinaric Karst in central Croatia. An important role of the soil in the karst is to purify the waters before they reach the phreatic zone. The soil is also a zone of accumulation, transformation, retardation and dilution of a potential pollut- ant. Knowing soil mineralogical composition is an important factor in understanding fate and transport of contaminants throughout lakes system. Samples of soil, peat and stream sed- iment were collected in the Prošće lake catchment and partly in the assumed zone of influence, X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FTIR) analysis of samples was performed to determine dominant mineral spe- cies in samples. XRD analysis showed predominance of low- quartz, which was found in all samples, most often as domi- nant phase. Dolomite was found in half of the samples, almost always as a significant phase while calcite was dominant phase in one of the samples. In most of the samples, members of the feldspars and chlorites groups, as well as muscovite, were present as minor phases. The absorption bands in the range of 2800-3000 cm -1 due to the organic matter are visible in spectra of all samples. These minerals can enter lakes system by sur- face waters, primarily streams and overland flow during snow thawing and rain, and also in cases of shore erosion. T errigenic input in lakes is small but cannot be neglected due to the long- lasting preservation efforts of the Prošće Lake recharge area, and the Plitvice Lakes National Park in general, terrigenous intake still does not pose a threat to water quality and tufa pro- duction. Izvleček UDKs 631.41:502.51(497.5Proščansko jezero) Anita Ptiček Siročić, Stanislav Kurajica, Dragana Dogančić & Nikolina Fišter: Tla in sedimenti zaledja Proščanskega jezera kot možen terigen doprinos v jezerski sistem Narodni park Plitviška jezera se nahaja v severozahodnem delu Dinarskega krasa v osrednji Hrvaški. Pomembna vloga tal v krasu je, da čistijo vodo, preden doseže freatično cono. Tla so tudi območje, kjer se potencialna onesnaževala kopiči- jo, preoblikujejo in redčijo. Tla ta onesnaževala tudi zadržijo. Poznavanje mineraloške sestave tal je pomemben dejavnik pri razumevanju prenosa onesnaževal v jezerskem sistemu. Tla, šoto in sedimente smo vzorčili v neposrednem zaledju in na vplivnem območju Prošćankega jezera. Mineralne vrste smo določili z rentgensko difrakcijo (XRD) in infrardečo spektro- skopijo s Fourierjevo transformacijo (FTIR). Analiza XRD je pokazala, da v vzorcih prevladuje kremen, ki je bil v vseh vzor- cih ugotovljen kot prevladujoč mineral. Dolomit je bil najden v polovici vzorcev, skoraj vedno kot pomemben mineral, med- tem ko je kalcit prevladoval samo v enem od vzorcev. V večini vzorcev so bili v manjšini še glinenci, kloritni minerali in mu- skovit. Absorpcijski pasovi na območju 2800-3000 cm -1 so bili zaradi organske snovi vidni v vseh spektrih. Minerale lahko v jezerski sistem prinesejo površinske vode, predvsem med taljenjem snega in ob padavinah ali obalni he- rozijskih procesi. Terigeni vnos je majhen, vendar ga zaradi dolgotrajnih prizadevanj za ohranitev in obnovo območja Pro- šćanskega jezera ni mogoče prezreti. Verjetno pa še ne ogroža kakovosti vode in nastajanja lehnjaka. Rezultati kažejo, da tla in sedimenti v zaledju Proščanskega je- zera učinkovito zadržijo in čistijo vodo na poti do jezera. Vse- eno lahko ob morebitnem onesnaženju v zaledju onesnaževala dosežejo jezerski sistem, če so adsorbirana na delce tal. Pozna- 1 Faculty of Geotechnical Engineering, University of Zagreb, Hallerova aleja 7, 42000 Varaždin, e-mail: aanitaps@gfv.unizg.hr; ddogan@gfv.unizg.hr; nfister@hotmail.com 2 Faculty of Chemical Engineering and Technology, University of Zagreb, Marulićev trg 19, 10000 Zagreb, e-mail: stankok@fkit.hr * Corresponding Author Received/Prejeto: 25.07.2019 DOI: 10.3986/ac.v49i1.7547 ACTA CARSOLOGICA 49/1, 125-140, POSTOJNA 2020 COBISS: 1.01 ANITA PTIČEK SIROČIĆ, STANISLAV KURAJICA, DRAGANA DOGANČIĆ & NIKOLINA FIŠTER INTRODUCTION Plitvice Lakes is the oldest and largest National Park in the Republic of Croatia. Its unique beauty and vulnerabil- ity were recognized by researchers and nature enthusiasts in late 19th and early 20th century which lead to procla- mation of National Park on April 8, 1949. In 1979 Plitvice Lakes have entered in the UNESCO World Heritage List and the total area under protection is 296.85 km 2 . The Plitvice Lakes National Park is located in the northwestern part of the Dinaric Karst between the mountains Lička Plješevica and Mala Kapela. The Park is situated in two counties, 90.7 % in Lika – Senj County and 9.3 % in Karlovac County (Fig. 1). The Plitvice Lakes catchment is almost entirely within the boundaries of the National Park. Unique geomorphological, hydrological, biogeochemical and biological phenomenon of the Plit- vice Lakes attracts around 1 million visitors a year mak- ing this area very susceptible to anthropogenic influence. Three main springs - the Black River, the White River, and the Plitvica spring feed the lakes with waters of exceptional quality. Hydrological system of 16 cascad- Considering the analyzed samples and characteristics of de- tected soil constituents, soils and sediments in the Prošće Lake catchment have the ability to retain and purify water on its way to the lakes. On the other hand, in case of the possible contami- nation in the recharge area of the lakes system, the pollutants can enter the system adsorbed on the soil particles. Learning more about the soils surrounding lakes gives valuable insight into their possible influence on lakes water chemistry and adds one piece of the puzzle into understanding this kind of a natural phenomenon. Key words: Plitvice Lakes National Park, FTIR, XRD, soil mi- neralogy, Croatia. Fig. 1: Position of investigated area (from Matin 2017). vanje tal v okolici in širšem zaledju jezera omogoča dragocen vpogled na njihov morebitni vpliv na kemijo vode v jezerih in prispeva k razumevanju tovrstnega naravnega pojava. Ključne besede: Narodni park Plitviška jezera, FTIR, XRD, mi- neralogija tal, Hrvaška. ACTA CARSOLOGICA 49/1 – 2020 126 SOILS AND SEDIMENTS OF PROŠĆE LAKE CATCHMENT AS A POSSIBLE TERRIGENOUS INPUT IN THE LAKES SYSTEM ing lakes separated by tufa barriers and waterfalls covers about 1 % of the total surface area of the park. The Park is traditionally divided in two parts - 12 Upper lakes, in- cluding biggest lakes Prošće (0.68 km 2 ) and Kozjak (0.82 km 2 ), and 4 Lower lakes. The Upper lakes are developed in the dolomite valley, surrounded by forests and inter- connected by numerous waterfalls. Smaller Lower Lakes are located on limestones. Lakes are unique for their autigenic calcite precipitation and a large population of calcifying cyanobacteria. Beside cyanobacteria, other microscopic and macroscopic organisms like diatomeae, protozoa, mosses and algae play very important role in tufa growth process (Meaški 2011). These organisms de- velop on the rocks and submerged objects. As the tufa barriers grow (1-3 cm/yr.), so does the water level result in changes of lake volume. According to Babinka (2007) total volume of the lakes is 22.95x10 6 m 3 . Water chemistry of mountain lakes is influenced by numerous factors like bedrock mineralogy, amount and composition of soils, slope, exposure and type of vegetation (Kamenik 2001). Changes in global climate trends, watercourse regulations, forestry and agricultural activities, leaking wastewater systems, war, and tourism represented a serious threat for this fragile ecosystem in the last decades (Sremac et al. 2012). Main focus of the researchers during the years has been the development of the tufa barriers and lakes but nowadays interest has shifted to protection of the recharge area of the main springs, protection of the lakes and waterfalls from grow- ing tourism development and broader protection of the karst environment from the impact of the National Park and its activities (Biondić et al. 2008). Focus is also set on chemical and physical properties of soil, since terrigenic input can be a significant source of trace elements in wa- ter and lake sediment. The solid soil phase is a mixture of organic substanc- es and minerals and makes up 30 to 60 % of the total soil content, the rest being air, water and living organisms. Soil mineral phase in some soils make up to 90 % of the soil solid phase (Chesworth 2008). The soil organic mat- ter, depending on the type of soil, makes on average 2-10 % of the solid phase content of the soil. Soil organic mat- ter is complex mixture composed of products resulting from microbial and chemical transformations of organic debris. Most soil organic matter originates from plant tis- sue and has a significant effect on the physical, chemi- cal, and biological properties of the soil by improving the capacity of a soil to hold water and nutrients which are then released slowly enabling better plant uptake and better conditions for plant growth. Organic matter from allochthonous source area can also enter lakes system via surface runoff during periods of snow thawing and in rain seasons. Source, concentration and composition might be among the factors influencing bacterial com- munity composition and their production, respiration and growth yield in the lakes (Kritzberg et al. 2006). Thickness of soil cover in the karst areas often var - ies and its central role is to purify the waters before they reach the phreatic zone. The soil serves as a medium for accumulation, retardation, dilution and transformation of a potential pollutant. Water-borne contaminants that permeate through the soil can be adsorbed onto the soil surface, bound to clay minerals, precipitated or move further through the soil. The effectiveness of soil to pro- tect groundwater from pollution depends on its thick- ness and composition, but also on other properties such as pH values, cation exchange capacity and clay mineral content. Composition and properties of the soil is one of the input parameters when assessing the intrinsic vul- nerability. Knowledge of the minerals comprising the soil inorganic component makes it possible to under- stand the weathering of minerals in surface conditions, determination of soil and sediment age and mechanisms of soil formation. Soil mineralogy can also help to ex- plain paleo-environmental conditions during pedogen- esis (Chesworth 2008). Also, knowing soil mineralogical composition is an important factor in understanding fate and transport of contaminants throughout lakes system. Related to Halamić & Miko (2009), during the explorato- ry works for the project of making a Geochemical map of Croatia sampling of soils of the Plitvice Lakes was carried out. Geochemical analysis of these samples showed no elevated values of heavy metals concentrations. Majority of methods used nowadays for characteriz- ing soil inorganic constituents were developed by chem- ists and physicist. Their area of interest were simple sys- tems, unlike soil, but despite that, these techniques found its application in characterization of soil minerals. Soil organic matter contains different functional groups with dipole moment which strongly influence properties of organic matter. That makes Fourier Trans- form Infrared spectroscopy (FTIR) a very suitable tech- nique for characterizing soil organic matter functional groups. Numerous O, N and S functional groups make organic matter highly reactive in reactions of cation ex- change and sorption of metals. One of the most signifi- cant functional group, the carboxyl group (C=O) can be well-characterized by FTIR spectroscopy (Margenot et al. 2017). Taking all the stated facts into consideration, it be- comes clear that soil mineralogy plays an important role in understanding the behavior of soil. Our aim was to determine main mineral constituents in soil by FTIR and XRD analysis and, based on results, to explain the possible role of detected minerals in environment of the Prošće Lake area. ACTA CARSOLOGICA 49/1 – 2020 127 ANITA PTIČEK SIROČIĆ, STANISLAV KURAJICA, DRAGANA DOGANČIĆ & NIKOLINA FIŠTER GEOLOGICAL AND GEOGRAPHICAL SETTING Plitvice Lakes catchment is a part of the Black Sea basin and according to the recent hydrological, hydrogeologi- cal and hydrogeochemical explorations the catchment can be divided into 3 subcatchments: Matica River, Lakes and Plitvica Spring subcatchment. Matica River sub- catchment covers around 55 % of the total area of the Plitvice Lakes and can be divided into 3 smaller hydro- geological units: the Black River, the White River and Ljeskovac stream (Meaški et al. 2016). Black and White Rivers bring most of the incoming waters to the lakes and after merging they form the Matica River before en- tering Prošćansko Lake. Prošćansko Lake is the second biggest and uppermost lake of the Plitvice Lakes system. Makjanić (1971) states that Plitvice Lakes are situated in the area between moderate warm rainy and snowy forest climates. According to Köppen-Geiger climate classifica- Fig. 2: Geological map of the Plitvice Lakes catchment (from Meaški 2011). ACTA CARSOLOGICA 49/1 – 2020 128 SOILS AND SEDIMENTS OF PROŠĆE LAKE CATCHMENT AS A POSSIBLE TERRIGENOUS INPUT IN THE LAKES SYSTEM tion this area has temperate humid climate without a dry season with a warm summer classified as climate type Cfb (Filipčić 1998; Kottek et al. 2006). Thick forests cover about 75.6 % of the area rest being short vegetation and meadows (Bonacci 2013). Forests form a protective zone around the lakes by preventing torrents and soil erosion, regulating runoff and drainage and also purifying rain- water and air. Bearing in mind the key role of forest eco- systems in the hydrological regime of the Plitvice Lakes, the central phenomena of Plitvice Lakes, tufa, is directly linked to the protection and conservation of forest eco- systems. From geological part of view, the Plitvice Lakes National Park is a karst environment composed of Up- per Triassic to Upper Cretaceous carbonate rocks (lime- stones and dolomites) (Fig. 2). Oldest rocks are Upper Triassic bedded dolomites which predominate around Upper Lakes and around streams Rječica and Sartuk. Poorly permeable Upper Triassic dolomites were essen- tial for the development of the Upper Lakes because they form a barrier to the discharge of water from a large ba- sin on the northeast slopes of Mala Kapela (Biondić et al. 2010). The Black River flows through Lower Jurassic dolomites with intercalations of limestones. The White River and spring Sušanj flow through area built mainly of Upper Jurassic bedded limestones with intercalations of dolomite and massive and crystalline dolomite. Part of their flow goes through the Middle Jurassic bedded limestone with intercalations of dolomite. Upper Cre- taceous rock are thick bedded and massive rudist lime- stone. This type of rocks builds the bottom and the flanks of the north-eastern part of the Kozjak Lake and part of the Korana River (Dautović et al. 2014). Miocene depos- its are present in northeastern part of National Park and outside park boundaries. Quaternary deposits appear in the areas of Korenička River, karst poljes Brezovačko and Homoljačko and spring Babin potok. T ectonics plays very important role in the formation of surface and groundwater systems in the karst environ- ments (Biondić et al. 2010). Carbonate rock are very brit- tle and crack easily when under pressure. In the Plitvice Lakes National Park limestones and dolomites are frac- tured into tectonic blocks by numerous faults (Fig. 2). Soils in the Plitvice Lakes area are classified as au- tomorphic soil. Their main characteristic is wetting through precipitation only with no additional wetting (Halamić & Miko 2009). The dominant type of soil is calcocambisol or brown limestone soil (soil developed on limestones and dolomites). Along with the calco- cambisol, there are also rendzinas, calcomelanosols and luvisols. Surface horizons have a significant amount of humus which effects many soil properties like, moisture and nutrients retention (Vrbek 2005). Soils are loamy in texture and soil cover is 15-80 cm thick throughout the catchment. In karst poljes soil cover is thicker (up to 2 m). Although 99 % of the Park surface is terrestrial en- vironment, very few studies were conducted of that area. Soils play a very important role in slowing down infil- tration of water and contaminants in karst underground (Romanić et al. 2016). According to Kamenik (2001) in case of mountainous lakes, water pH increases with in- creasing soil cover. Lakes are very vulnerable systems due to input of various materials via surface runoff, wastewater dis- charge and atmospheric deposition (Mikac et al. 2011). In pristine lakes, like the ones in Plitvice Lakes National Park, trace elements input depends primarily on the local geology and weathering rates (Zaharescu et al. 2009). The ability of metals to bind to different particles depends on the specific surface area and affinity for dif - ferent active sites (Dautović et al. 2014). Mineralogical characterization of complex samples, like soils, is an im- portant way of determining their physical and chemical characteristic and functionality. Mineralogy strongly affects soil-water and soil-water-contaminant interac- tion and knowledge of the same is very important for solving several problems encountered in geoenviron- mental engineering. METHODS SAMPLING During the May 2017, 10 samples of soil, peat and stream sediment were collected in the Prošće Lake catchment and partly in the assumed zone of influence (Fig. 3; Tab. 1). Prior to drying, all the impurities like leaves, twigs, branches were removed. Samples were airdried at room temperature to prevent the loss of any volatile elements. Completely dried samples were milled in agate mortar and sieved. The goal was to get fine enough sample parti- cle size to obtain adequate statistical representation of the components and their various diffraction crystal planes and also to avoid any diffraction related artifacts (Bish & Reynolds 1989) ACTA CARSOLOGICA 49/1 – 2020 129 ANITA PTIČEK SIROČIĆ, STANISLAV KURAJICA, DRAGANA DOGANČIĆ & NIKOLINA FIŠTER Fig. 3: Geological map of Prošće Lake catchment with soil sampling locations (Meaški et al. 2016). Tab. 1: Samples description. Sample Sample type Underlying rocks PL-1 forest soil near lake Prošće Triassic dolomites PL-2 meadow soil behind restaurant Triassic dolomites/tufa PL-3 stream sediment tufa PL-4 forest soil near lake Prošće Triassic dolomites PL-5 peat near river Matica tufa/Triassic dolomites PL-6 soil near river Matica Triassic dolomites PL-7 soil from sinkhole Jurassic limestones and dolomites PL-8 meadow soil outside settlement Jurassic limestones and dolomites PL-9 soil from Uvalica meadow Cretaceous limestones and dolomites PL-10 soil at vicinity of local road Triassic dolomites ACTA CARSOLOGICA 49/1 – 2020 130 SOILS AND SEDIMENTS OF PROŠĆE LAKE CATCHMENT AS A POSSIBLE TERRIGENOUS INPUT IN THE LAKES SYSTEM FOURIER TRANSFORM INFRARED SPECTROSCOPY (FTIR) FTIR analysis has a wide range of applications, from or- ganic synthesis, polymer science, petrochemical engi- neering to pharmaceutical industry and food analysis. When analyzing the soil, FTIR gives an insight into the composition of the functional groups of present miner- als and organic matter. One of the advantages of FTIR is the possibility to identify non-crystalline and amorphous materials (Margenot et al. 2017). The FTIR measurement was carried out using a Perkin Elmer FTIR Spectrum One Infrared Spectrometer equipped with an attenuated total reflection accessory (ATR). All the spectra were ac- quired in the range from 4000 cm −1 to 600 cm −1 with a spectral resolution of 4 cm −1 . Since FTIR is usually used in combination with some other techniques, XRD was chosen as a second characterization technique. X-RAY DIFFRACTION (XRD) XRD is a rapid analytical technique primarily used for the identification of unknown crystalline materials like minerals and inorganic compounds. X-ray diffraction analysis (XRD) is a technique that provides information on phase composition and crystal structure of the ma- terial. Mineral identification is based on d-spacing and relative peak intensities and is much easier if sample con- tains only one type of the mineral. Soil mineral phase, on the other hand, is a mixture of different minerals who’s complex XRD patterns can present a challenge for the identification. One of the main limitations of XRD technique is the detection limit, which is around 1 % of weight (Bruckman & Wriessnig 2013). The mineralogical composition of ground bulk soil samples was determined by X-ray diffraction (XRD) analysis using a Shimadzu XRD–6000 equipped with CuKα radiation operating at 40 kV and of 30 mA. The diffraction patterns were obtained from 5° to 75° 2θ in a step-scan mode with steps of 0.02° 2θ and counting time of 0.6 s. The mineralogical identification was based on the comparison with a database. RESULTS AND DISCUSSION FTIR FTIR analysis of the bulk soil samples determined the presence of quartz in all analyzed samples. Organic mat- ter and clay minerals, most likely kaolinite, are also pres- ent in majority of samples. In addition, the minerals in the carbonate group (calcite) and the silicate mineral chlorite have been detected. FTIR spectra of the studied samples are presented in Figs. 4-7. Detailed examination of the FTIR diagrams of the soil samples revealed different functional groups charac- teristic for the organic matter. The small band observed at 3380 cm -1 in samples PL-1 (Fig. 4), PL-3, PL-4 (Fig. 5) and PL-8 (Fig. 6) correspond to amide N-H stretch. The bands in the range of 2800 - 3000 cm -1 and around 1420 cm -1 are due to aliphatic C-H symmetric stretching mode vibrations of the organic matter and are visible in spectra of all samples. A few samples (PL-5 to PL-9) (Fig. 6) have broad band around 1650 cm -1 which is characteristic for aromat- ic C=C bending vibration and/or amide C=O functional groups. Samples PL-4 and PL-7 have small bands at 3030 cm -1 which can be attributed to aromatic C-H stretching vibrations. Strong peaks visible around 2100 in major- ity of samples corresponds well with band characteristic for alkynyl C=C stretching vibration. Bands characteris- tic for other important functional groups like polysac- charides (1018 cm -1 ) most likely overlap with mineral absorbances in the range 1400-800 cm -1 (Margenot et al. 2017). As stated before, soils have very small amount of organic matter in comparison to mineral content. One of the limitations in using FTIR for soil organic matter characterization arises from mineral dominance and in- terferences, in particular Si-O bands. Soil minerals, through interaction with soil water, affect soil physical properties and behavior like soil plas- ticity, swelling, permeability to air/water and aggregate stability. Nature of secondary mineral phase that forms in situ during weathering of primary minerals silicate minerals have a significant impact on soil characteristics. Clay minerals are the most abundant secondary miner- als that dominate finegrained (< 2 mm) fraction of soil and are developed in humid-temperate or warmer areas (Quirk 1996). Soil mineral phase in majority of soils is a complex mixture of phyllosilicate minerals which are most common minerals in soils and are composed of one or two sheets of Si (or isomorphically substituted Al) in tetrahedral coordination with O fused to cations in oc- tahedral coordination with O or OH. Main characteris- tics of most secondary minerals are small particle size, high surface area and a net negative charge which enables them to participate in reactions with water molecules, nutrients, heavy metals, organic pollutants and toxic ACTA CARSOLOGICA 49/1 – 2020 131 ANITA PTIČEK SIROČIĆ, STANISLAV KURAJICA, DRAGANA DOGANČIĆ & NIKOLINA FIŠTER contaminants (Chesworth 2008). According to Kapelj et al. (2018) soils from Prošće Lake catchment have slightly acidic to neutral pH reaction and dominantly net nega- tive charge. Unlike organic matter, minerals have smaller ab- sorption bands of greater intensity (Ramasamy et al. 2009). Peaks were determined for most important in- frared-active groups occurring in mineral soils. The ob- tained results, with fewer exceptions, are well-matched with the absorption peak values of silicates and carbon- ates mentioned in the literature and the available FTIR spectrum databases. Small variations in values of O-H bond stretching and bending vibrations is due to differ- ent strength of hydrogen bond between O-H and H 2 O and oxygen in structures of minerals. The Si-O bonds are the strongest bonds in the struc- ture of silicate minerals and are easily detected on FTIR spectra. Silicate minerals have strong absorption bands ranging from 1100 to 900 cm -1 due to Si-O stretching and less intense bands ranging from 400 to 800 cm -1 due to Si-O bending. The presence of quartz is cause of sym- metrical bending in the range of 690 - 695 cm -1 and the Fig. 4: FTIR spectra for soil samples PL-1 and PL-2. Fig. 5: FTIR spectra of stream sedi- ment sample PL-3 and soil sample PL-4. ACTA CARSOLOGICA 49/1 – 2020 132 SOILS AND SEDIMENTS OF PROŠĆE LAKE CATCHMENT AS A POSSIBLE TERRIGENOUS INPUT IN THE LAKES SYSTEM vibration bands due to the symmetric stretching in the range of 776-780 and 795-800 cm -1 . Bands characteristic for quartz are present in the spectra of all samples and are in good agreement with observations for the quartz mineral made by Ponnusamy et al. (2009) and Boldea et al. (2013). FTIR spectra of clay minerals are complicated since the intensity and position of the absorption bands de- pends on the chemical composition and origin of clays, especially the presence of impurities (Khang et al. 2016). The doublet band visible in samples PL-3, PL-5, PL-7, PL-9 and PL-10 (Figs. 5-7) in the range 1008 - 1032 cm -1 corresponds to the Si-O-Al and Si-O-Si stretching and the 1090 cm -1 band observed in samples PL-3, PL-9 and PL-10 is due to normal-to-the-plane stretching of Si-O- Si in aluminosilicate minerals, possibly illite. (Figs. 5-7) (Davarcioglu 2010: Essomba et al. 2014). Illite is a is a common mineral found in soils and sediments. Four bands at 3697 cm -1 , 3662 cm -1 , 3648 cm -1 , 3620 cm -1 pre- sent in samples are due to OH stretching in water mole- cules that may be an integral part of the mineral kaolinite (Fadil-Djenabou et al. 2015: Khang et al. 2016). Bands Fig. 6: FTIR spectra of soil samples PL-5, PL-6, PL-7, PL-8 and PL-9. Fig. 7: FTIR spectra of soil sample PL-10. ACTA CARSOLOGICA 49/1 – 2020 133 ANITA PTIČEK SIROČIĆ, STANISLAV KURAJICA, DRAGANA DOGANČIĆ & NIKOLINA FIŠTER in the range 1698 to 1521 cm -1 can be ascribed to the bending mode of H 2 O molecules in the kaolinite. Kao- linite is a common soil mineral with a structural formula Al 2 Si 2 O 5 (OH) 4 . It is a typical dioctahedral species with triclinic symmetry (Senthil Kumar & Rajkumar 2014). Both organic matter and clay minerals, have an important role due to good ion exchange capacity in binding metal cations from water into a solid phase. Cation exchange capacity (CEC) values for soil samples from Prošće Lake catchment range from 16 to 175 cmol(+)/kg confirming the dominant influence of minerals like kaolinite and il- lite in majority of samples and organic matter in samples PL-1 (forest soil) and PL-5 (peat) (Kapelj et al. 2018). Vibration bands centered at about 1600 cm −1 and 3400 cm -1 (3434, 3565, 3662 cm -1 ) in samples PL-2, PL-4, PL-6, PL-7 and PL-9 are result of bending and stretching of O-H bond which in our case is included in the trans- mittance spectrum of chlorite (Figs. 4-6) (Boldea et al. 2013: Fadil-Djenabou et al. 2015). Chlorite is a common weathering mineral whose structure consist of 2:1 layer with hydroxide sheet in the interlayer region. Since Mg and Fe are major octahedral cations in chlorite structure, due to chlorite environmental instability, it accounts for significant amount of Mg and other nutrients released to the soil solution (Proust et al. 1985). Peaks characteristic for carbonate minerals are present in spectra of majority of samples. The absorption bands in the range 1420 - 1460 cm -1 in the room tempera- ture FTIR spectra are the result of asymmetric stretching (Gunasekaran & Anbalagan 2007). According to Socrates (2001) and Boldea et al. (2013) bands at 1432 and 874 cm -1 can be attributed to a functional CO 3 2- group. Also, peaks characteristic for carbonates were observed at 726 cm -1 (vibrational bending), and at 881 cm -1 (out-of- plane bending). Strong absorption bands in the range 2300-2600 cm -1 can be attributed to calcite CaCO 3 (Du & Zhou 2009). Band at 2628 cm -1 is due to C-O symmet- ric stretching mode vibration. Results obtained by FTIR analysis were confirmed by XRD analysis of samples. The obtained results show that the studied samples contain minerals characteristic for soils developed on bedrock made of limestones and dolomites. Also, the composition of the soil is influenced by the rich plant cover characteristic for The Plitvice Lakes National Park, which is the source of organic matter in the soil. XRD Results of the X-ray powder diffraction analysis of the soil samples collected in Plitvice lakes catchment area are presented in the Tab. 2 and Figs. 8-9. As can be seen, 6 major mineral constituents are detected in studied samples. Quartz is present in all samples while only the sample PL-3 contains calcite. Dolomite, feldspar, chlorite and muscovite are present in majority of samples. Sample PL-3 contains all detected minerals (Fig. 9). Unlike other samples, which are samples of soils, sample PL-3 is a stream sediment (Tab. 1). Halamić et al. (2001) defines stream sediment as “silty fraction (clay to fine- grained sand) transported and deposited in a recent stream channel.” It is a composite material whose pe- trographic, mineralogical and geochemical composition roughly reflects the bedrock lithology upstream from the sampling site in case the anthropologic influences are low or absent. Stream sediment is a result of erosion and transport of soil and rock debris, and other materi- als within catchment basin upstream of the sampling site (De Vos et al. 2019). In this case, stream sediment was taken at the exit point of Prošće lake and is a good repre- sentation of material being introduced into lakes system. Since quartz is one of minerals most resistant to chemical weathering in soils and stable at ambient condi- tions (Glinneman et al. 1992), it is common and invari- ably present in all the samples. Dominant peaks for low- temperature quartz are at 26.64° and 20.86° 2θ (Fig. 8). Tab. 2: Mineralogical composition of investigated samples by XRD analysis: + (present), - (not detected). Sample Quartz Calcite Dolomite Feldspar Chlorite Muscovite PL-1 + - + + + - PL-2 + - - + + + PL-3 + + + + + + PL-4 + - + - - - PL-5 + - - + + + PL-6 + - - + + + PL-7 + - + + + + PL-8 + - - + + + PL-9 + - - + + + PL-10 + - + - - - ACTA CARSOLOGICA 49/1 – 2020 134 SOILS AND SEDIMENTS OF PROŠĆE LAKE CATCHMENT AS A POSSIBLE TERRIGENOUS INPUT IN THE LAKES SYSTEM Samples contain considerable amounts of clay minerals and other layered silicates. Chlorite resembles Mg 2.96 Fe 1.55 Fe 0.136 Al 1.275 Si 2.662 Al 1.376 O 10 (OH) 8, one of the most common members of the chlorite group. Clinochlore is a detrital component of sediments often associated with dolomite, calcite and plagioclase. Muscovite is present in majority of samples (Tab. 2). Feldspar detected by XRD in samples is determined as the closest to anorthoclase Na 0.667 K 0.333 AlSiO 8 . Anor- thoclase is an alkali feldspar and is a common member of sodium-rich igneous rocks. Carbonate minerals are very important component of the soil influencing chemical and physical properties like soil pH and buffer capacity. Carbonates in soil typi- cally occur as calcite or dolomite depending on the par- ent material and soil formation processes (Bruckman & Wriessnig 2013). Differentiation of soil carbonates into calcite and dolomite is valuable for determining sources of soil parent materials, degree of carbonate weathering, types of secondary carbonates, and the occurrence of dolomitization (Petersen et al. 1966). X-Ray diffraction allows a distinct differentiation between calcite CaCO 3 and dolomite (Ca,Mg)CO 3 . Dominant peak for calcite is present at 29.4° 2θ and for dolomite at 30.96° 2θ (Fig. 9). Fig. 8: Diffractogram of the sample PL-1. Fig. 9: Diffractogram of the sample PL-3. ACTA CARSOLOGICA 49/1 – 2020 135 ANITA PTIČEK SIROČIĆ, STANISLAV KURAJICA, DRAGANA DOGANČIĆ & NIKOLINA FIŠTER X-ray diffractogram of sample PL-3 is the only one showing calcite in significant amounts (Fig. 9). This is expected since underlying rock is tufa, porous sedimen- tary rock built mainly from calcium carbonate. Calcite is prone to chemical weathering and has a better solubility in weak acids like precipitation and humic acids in soils in comparison to dolomite. The results obtained by XRD soil analysis were com- pared with the results of Prošće Lake sediment analyzed by Popović et al. (1986). The study found that dominant mineral is quartz along with other rock forming minerals like feldspar, mica, chlorite and with traces of calcite and dolomite. Almost identical mineralogical composition of investigated soil samples and core samples taken from the Prošće Lake indicate there is a terrigenic input of soil material to the lake system. Occasionally minerals species identified through FTIR can be absent in the XRD analysis. Reason could be in disorder and the loss of crystalline nature of the respective minerals or in the low detection limits of XRD for small quantities of minerals in mixed samples. Even the small amount of clay minerals (in form of coatings) can play a significant role in functioning of an ecosys- tem by affecting water storage properties, water quality, cation exchange capacity, etc. Good example for that is illite whose characteristic functional group vibrations were present in FTIR spectra but were not detected by XRD probably due to small amount of illite in samples. Also, the XRD peaks of some of the main soil minerals, like kaolinite, muscovite, sillimanite, may overlap with the strongest peak and other peaks of quartz (Singh & Agrawal 2012). ENVIRONMENTAL SIGNIFICANCE OF DETECTED SOIL CONSTITUENTS Sedimentary material that originates outside the lakes is to be referred as allogenic. Different minerals can be brought into the lakes by surface waters, mainly streams and overland flow during snow thawing and rain, and during shore erosion. Forests, on the one hand, protect lakes, and on the other, they are sources of organic matter, especially dur- ing the fall, increasing the possibility of eutrophication of the lakes (Biondić et al. 2017). All analyzed samples contain organic matter especially sample PL-5 which was taken from peat bog located at the confluence of Matica river to Prošće lake. Hence, when entering the lake, the waters of Matica are already enriched with organic mat- ter. Organic matter plays an important role in process of lake formation since higher concentrations of it in water inhibit tufa production. Study made by Srdoč et al. (1985) showed that important factors in process of tufa forma- tion are water pH above 8, flow rate between 0.5-3.5 m/s, low concentrations of dissolved organic matter and activ- ity of organisms, mainly mosses, algae and grasses. The analysis of cores taken from lake Prošće and Kozjak have shown high content of organic matter and related high concentrations of phosphorus. Organic matter can also serve as the means of transportation for heavy metals and other pollutants. Horvatinčić et al. (2006) noticed positive correlation between concentrations of organic carbon and concentrations of Pb, Cd and Zn. Also, con- centrations of organic matter decrease downstream. Dispersed clay-size particles of soils and sediments contribute to the suspended load in surface waters and serve as the means of nutrients and contamination trans- port via adsorption to particle surface. Based on soil min- eralogy, predictions can be made about soil’s tendency to disperse. Soils rich in smectites are highly dispersive and more likely to end up in surface waters than soils rich in kaolinite or illite (Calero et al. 2008). Smectite was not detected in the tested soils, which significantly reduces the possibility of dispersion of the observed soils. The most abundant mineral in the samples is quartz because of its thermodynamic resistance to weathering. Quartz can be of eolian origin or it can be a residue af- ter dissolution of limestones containing small amount of quartz. Quartz has a very low CEC value since it has al- most insignificant amount of charge. When compared to other soil minerals, quartz has almost diluting effect on the overall value of CEC (Dixon & Schulze 2002). Since quartz is the most common mineral in the mineral phase of soil, it is expected that it is also present in lake sedi- ments. Concentrations of quartz in core samples taken from Prošće lake fluctuate around 10 % along 40 cm long sediment core representing 100 – 200 years of sedimenta- tion. (Horvatinčić et al. 2006). Minor variations in con- centration reflect the fairly constant input of terrigenous material in the Prošće lake over the years. Muscovite is a widely distributed soil component whose dissolution is a possible source of K and Mg in the soil solution. Estimating the capacity of micaceous minerals to supply K to the soil solution is a key for es- timate of plant nutrition and development. Healthy and well-developed vegetation has a substantial influence on precipitation, transport and deposition of ions and nutri- ents. Water infiltration is much slower on terrains cov- ACTA CARSOLOGICA 49/1 – 2020 136 SOILS AND SEDIMENTS OF PROŠĆE LAKE CATCHMENT AS A POSSIBLE TERRIGENOUS INPUT IN THE LAKES SYSTEM ered with thick vegetation and also, erosion processes are much slower. On the other hand, soil and vegetation en- hance chemical weathering through hydrological impact and by providing organic acids (Kamenik 2001). Size of the particles also has a noteworthy role since smaller par- ticles loose K faster than the bigger one (Dixon & Schulze 2002). Also, alteration of micas, including muscovite, in diagenetic environments results in formation of expand- able 2:1 phyllosilicates of the vermiculite and smectite groups (Kalinowski & Schweda 1996). Muscovite has a considerably lower cation exchange capacity (CEC) than smectites because only its surface cations can be exchanged at room temperature (Osman & Suter 2000). Chlorite detected in soil samples has a substantial amount of iron in formula. Structural Fe 2+ plays a sig- nificant role in weathering of Fe-containing species. Weathering of chlorites occurs through progressive hy- dration of the interlayer hydroxide sheet with consequent loss of cations and results in formation of vermiculite or smectite both having very high CEC values. Nitrate con- tamination of groundwater has become a grave risk in some areas of world. Nitrogen is an essential nutrient in aquatic ecosystems but rise in nutrient availability can re- sult in eutrophication. Chemical changes are followed by changes in biological productivity, the composition and variety of biota and, accordingly, in physical status of wa- ter bodies (Hornung 1999). Ferrous ion in chlorites can reduce NO 3 - to NH 4 + (Ernsten 1996) and may contribute to the removal of organic contaminants and NO 3 - from the soil solution and groundwater under reducing condi- tions. Calcite and dolomite in soil samples can originate from underlying limestones, dolomites and tufas and cannot be considered pedogenic, unlike the calcite and dolomite that can be formed by dissolution and repre- cipitation of calcium and magnesium containing miner- als or it can be part of wind and tropospheric deposition. The amount of the dissolved organic matter (DOC) in soils are very important since even the low levels of DOC can inhibit calcite nucleation and precipitation. Calcite is a significant scavenger of several trace elements and plant nutrients (P , Sr, Pb) in natural setting. It provides a surface for direct sorption of metal ions and it influences soil pH. Chemisorption of elements on calcite depends primarily of their ionic radius and can be a very fast process, in some cases almost irreversible (for example, chemisorption of Cd). Surface protonation – deproton- ation reactions on calcite create negative surface charge at pH values 8,5 to 9 and positive charge below that pH range (Dixon & Schulze, 2002). Soil of the area of inter- est are slightly acidic to neutral so it is expected that cal- cite has a positive surface charge and can bind negatively charged ions and particles. Calcite has been found to be the dominant mineral phase in recent lake sediments with concentrations up to 70 % (Horvatinčić et al. 2006; Horvatinčić et al. 2014). It is expected that most calcite in lake sediments is autigenic, but it cannot be neglected that one small part is of terrigenous origin and primarily occurs in the sediments of Prošće Lake in the vicinity of the Matica river. CONCLUSION The Plitvice Lakes are very vulnerable aquatic ecosystem which is exposed to significant inputs of materials from their recharge areas. Its unique beauty attracts around 1 million visitors a year making this fragile ecosystem very susceptible to anthropogenic influence. In order to main- tain the continuity of the tufa production, it is essential to maintain exceptional water quality. Since terrigenic input can also be a source of different pollutants in water and lake sediment, it is important to understand physical- chemical characteristics of the soil in recharge area, spe- cifically mineralogical composition of soils. FTIR and XRD analysis of soil, peat and stream sediment samples gave us insight into soil mineralogy and characteristics that come from it. FTIR and XRD re- sults shown that dominant minerals in studied samples are quartz, muscovite, feldspar, chlorite, calcite and do- lomite and soils contain significant amounts of organic matter. Considering the analyzed samples and character- istics of detected soil constituents, soils and sediments in the Prošće Lake catchment have the ability to retain and purify water on its way to the lakes. On the other hand, terrigenic input, although small, cannot be neglected. In case of the possible contamination in the recharge area of the lakes system, the pollutants can enter the system adsorbed on the soil particles. Due to the preservation and good condition of the forests and soils in the catch- ment of lake Prošće, terrigenous intake still does not pose a threat to water quality and tufa production. Learning more about the soils surrounding lakes gives valuable in- sight into their possible influence on lakes water chemis- try and adds one piece of the puzzle into understanding this kind of a natural phenomenon. ACTA CARSOLOGICA 49/1 – 2020 137 ANITA PTIČEK SIROČIĆ, STANISLAV KURAJICA, DRAGANA DOGANČIĆ & NIKOLINA FIŠTER ACKNOWLEDGMENTS The work has been supported by Plitvice Lakes National Park Public Institution through research project entitled “Hydrodynamic modeling of the Plitvice Lakes system” and with assistance of employees of Dr. Ivo Pevalek Sci- entific Research Center. REFERENCES Babinka, S., 2007: Multi-tracer study of karst waters and lake sediments in Croatia and Bosnia and Herzegov- ina: Plitvice Lakes, National Park and Bihać area.- Ph.D. thesis, Rheinischen Friedruch-Wilhelms- Universitat, Bonn, Germany, pp. 167. Biondić, B., Zojer, H., Biondić, R., Beyene, Y., Kapelj, S., Meaški, H. & G. Zwicker, 2008: Mountainous lakes – Sustainable utilization of water in the pilot area Plitvice Lakes.- In: Probst, G. et al. (eds.): Wasser- ressourcen und deren Bewirt- schaftung – Die Bedeu- tung von Netzwerken. Internationale Fachtagung. Kompetenznetzwerk Wasserressourcen GmbH, pp. 109–117, Graz. Biondić, B., Biondić, R. & H. Meaški, 2010: The concep- tual hydrogeological model of the Plitvice Lakes.- Geologia Croatica, 63, 2, 195–206. https://doi. org/10.4154/gc.2010.17 Biondić, B., Biondić, R. & H. Meaški, 2017: Water re- sources protection in the NP Plitvice Lakes.- In: Proceedings of Scientific and technical conference with international participation Managing lakes and reservoirs in Croatia - process, protection and evalua- tion and round table on current problems of Vransko lake near Biograd na Moru, May 4-6, 2017. Bish, D.L. & R.C. Reynolds, Jr. 1989: Sample prepara- tion for X-ray diffraction.- In: Bish D.L. & J.E. Post (eds.): Modern Powder Diffraction, Reviews in Min- eralogy 20, Mineralogical Society of America, pp. 73-99, Washington, D.C. Boldea, D. A., Praisler, M., Quaranta, M., & V . Minguzzi, 2013: Multi-technique characterisation of painted eneolithic ceramics originating from Cucuteni (Ro- mania).- European Journal of Science and Theology, 9, 4, 253-262. http://dx.doi.org/10.1016/j.jeurce- ramsoc.2017.07.018. Bruckman, V. J. & K. Wriessnig, 2013: Improved soil carbonate determination by FT-IR and X-ray analy- sis.- Environmental Chemistry Letters, 11, 1, 65-70. https://doi.org/10.1007/s10311-012-0380-4 Calero, N., Barrón, V . & J. Torrent, 2008: Water dispers- ible clay in calcareous soils of southwestern Spain.- CATENA, 74, 1, 22–30. https://doi.org/10.1016/j. catena.2007.12.007 Chesworth, W., 2008. Encyclopedia of Soil Science.- Springer, pp. 902, Netherlands. Dautović, J., Fiket, Ž., Barešić, J., Ahel, M. & N. Mikac, 2014: Sources, Distribution and Behavior of Major and Trace Elements in a Complex Karst Lake Sys- tem.- Aquatic Geochemistry, 20, 19–38. https://doi. org/10.1007/s10498-013-9204-9 Davarcioglu, B., 2010: Investigation of Central Anatolian region Nigde-Dikilitas (Turkey) clays by FTIR spec- troscopy.- Journal of Silicate Based and Composite Materials, 62, 2, 55-60. http://dx.doi.org//10.14382/ epitoanyag-jsbcm.2010.12 Davarcioglu, B., 2012: Kolsuz-Ulukisla-Nigde Clays, Central Anatolian Region – Turkey and Petroleum Exploration.- Clay Minerals in Nature - Their Char- acterization, Modification and Application, 1, 39– 54. https://doi.org/10.5772/48286 De Vos, W., Batista, M.J., Pirc, S., O’Connor, P.J., De- metriades, A., Tarvainen, T., Salminen, R., Reeder, S., Salpeteur, I. & V. Gregorauskiene, 2019: Distri- bution of elements in stream sediment.- [Online] Available from: http://weppi.gtk.fi/publ/foregsatlas/ article2.php?id=28 [Accessed 26th January 2019] Dixon. J. B. & D. Schulze (eds.), 2002: Soil Mineralogy with Environmental Applications.- SSSA Book series 7, Soil Science Society of America, pp. 866, Madi- son, Wisconsin, USA. Du, C. & J. Zhou, 2009: Evaluation of soil fertility using infrared spectroscopy: A review.- Environmen- tal Chemistry Letters, 7, 2, 97–113. https://doi. org/10.1007/s10311-008-0166-x Ernsten, V., 1996: Reduction of nitrate by Fe 2+ in clay minerals.- Clays and Clay Minerals, 44, 5, 599-608. Essomba, J. S., Nsami, N. J., Belibi Belibi, P.D., Merlain Tagne, G. & J. Ketcha Mbadcam, 2014: Adsorp- tion of cadmium (II) ions from aqueous solu- tion onto kaolinite and metakaolinite.- Pure and Applied Chemical Sciences, 2, 11-30. http://doi. org/10.12988/pacs.2014.31017 Fadil-Djenabou, S., Ndjigui, P. D. & J. A. Mbey, 2015: ACTA CARSOLOGICA 49/1 – 2020 138 SOILS AND SEDIMENTS OF PROŠĆE LAKE CATCHMENT AS A POSSIBLE TERRIGENOUS INPUT IN THE LAKES SYSTEM Mineralogical and physicochemical characteriza- tion of Ngaye alluvial clays (Northern Cameroon) and assessment of its suitability in ceramic produc- tion.- Journal of Asian Ceramic Societies, 3, 1, 50- 58. http://doi.org/10.1016/j.jascer.2014.10.008 Filipčić, A., 1998: Climatic regionalization of Croatia ac- cording to W . Köppen for the standard period 1961- 1990 in relation to the period 1931-1960 [in Croa- tian].- Acta Geographica Croatica, 33, 1-15. Glinnemann, J. I., King, H. E., Schulz, H., Hahn, T., La Placa, S. J. & F . Dacol, 1992: Crystal structures of the low-temperature quartz-type phases of SiO2 and GeO2 at elevated pressure.- Zeitschrift für Kristal- lographie, 198, 177–212. https://doi.org/10.1524/ zkri.1992.198.14.177 Gunasekaran, S. & G. Anbalagan, 2007: Thermal decom- position of natural dolomit.- Bulletin of Materials Science, 30, 4, 339–344. http://doi.org/10.1134/ S0020168511120156 Halamić, J. & S. Miko (eds.), 2009: Geochemical Atlas of the Republic of Croatia.- Croatian Geological Sur- vey, pp. 87, Zagreb. Halamić, J., Peh, Z., Bukovec, D., Miko, S. & L. Galović, 2001: A Factor Model of the Relationship between Stream Sediment Geochemistry and Adjacent Drainage Basin Lithology, Medvednica Mt., Croa- tia.- Geologia Croatica, 54, 1, 37-51. Hornung, M., 1999: The Role of Nitrates in the Eutro- phication and Acidification of Surface Waters.- In: Wilson W .S. et al. (eds.) Managing Risks of Nitrates to Humans and the Environment. Woodhead Pub- lishing, pp. 155–174, Sawston, Cambridge. http:// doi.org/10.1533/9781845693206.155 Horvatinčić, N., Briansó, J. L., Obelić, B., Barešić, J. & I. Krajcar Bronić, 2006: Study of pollution of the Plit- vice Lakes by water and sediment analyses.- Water, Air, & Soil Pollution: Focus, 6, 475-485. http://doi. org/10.1007/s11267-006-9031-8 Horvatinčić, N., Sondi, I., Barešić, J., Sironić, A., Kraj- car Bronić, I., Obelić, B., Vdović, N. & A. Rajtarić, 2014: Utjecaj klimatskih promjena i stanja u okolišu na biološki inducirano taloženje sedre i sedimen- tacijske procese u Plitvičkim jezerima.- Završno izvješće IRB-ZEF-2014/2. Kalinowski, B. E. & P. Schweda, 1996: Kinetics of mus- covite, phlogopite, and biotite dissolution and al- teration at pH 1-4, room temperature.- Geochimica et Cosmochimica Acta, 60, 3, 367-385. https://doi. org/10.1016/0016-7037(95)00411-4 Kapelj, S., Dogančić, D., Plantak, I. & J. Loborec, 2018: Origin and distribution of cadmium in soils of NP Plitvice Lakes. In: Rubinić J. et al. (eds.): Proceed- ings of Hydrology in service of water protection, water use and flood risk reduction – recent trends and ap- proaches, 18-20 th October 2018 Brela, Croatia. Croa- tian Hydrological Society, 45-52, Zagreb. Khang, V. C., Korovkin, M. V. & L. G. Ananyeva, 2016: Identification of clay minerals in reservoir rocks by FTIR spectroscopy.- In: OP Conference Series: Earth and Environmental Science, Volume 43, XX International Scientific Symposium of Students, Post- graduates and Young Scientists on “Problems of Ge- ology and Subsurface Development” 4–8 April 2016, Tomsk, Russia 43, 1. http://doi.org/10.1088/1755- 1315/43/1/012004 Kottek, M., Grieser, J., Beck, C., Rudolf, B. & F. Rubel, 2006: World Map of the Köppen-Geiger Climate Classification Updated.- Meteorologische Zeit- schrift. 15, 259-263. http://doi.org/10.1127/0941- 2948/2006/0130 Kritzberg, E. S., Langenheder S. & E. S. Lindström, 2006. Influence of dissolved organic matter source on lake bacterioplankton structure and function – implications for seasonal dynamics of com- munity composition.- FEMS Microbiology Ecol- ogy, 56, 3, 406–417. https://doi.org/10.1111/j.1574- 6941.2006.00084.x Margenot, A. J., Calderón, F. J., Goyne, K. W ., Mukome, F. N. & S. J. Parikh, 2017: IR Spectroscopy, Soil Analysis Applications.- In: Lindon J.C. et al. (eds.) Encyclopedia of Spectroscopy and Spectrometry. Aca- demic Press, pp. 448–454, Cambridge, Massachu- setts. https://doi.org/10.1016/B978-0-12-409547- 2.12170-5 Matin, J., 2017: Procjena ranjivosti krških vodonosnika na primjeru sliva Plitvičkih jezera.- Master thesis. University of Zagreb, Faculty of Geotechnical En- gineering, pp. 53. Meaški, H., 2011: Model of the karst water resources pro- tection on the example of the Plitvice Lakes Nation- al Park.- PhD thesis. University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering, pp. 210. Meaški. H., Biondić, B. & R. Biondić, 2016: Delineation of the Plitvice Lakes karst catchment area, Croatia.- In: Stevanović, Z. et al. (eds.), Karst without Bound- aries. CRC Press/Balkema, pp. 269-284, Holland. Mikac, I., Fiket, Ž., Terzić, S., Barešić, J., Mikac, N. & M. Ahel, 2011: Chemical indicators of anthropo- genic impacts in sediments of the pristine karst lakes.- Chemosphere, 84, 8, 1140-1149. https://doi. org/10.1006/jcis.1999.6677 Osman, M. A. & U. W. Suter, 2000: Determination of the Cation-Exchange Capacity of Muscovite Mica.- Journal of Colloid and Interface Science, 224, 1, 112–115. https://doi.org/10.1006/jcis.1999.6677 ACTA CARSOLOGICA 49/1 – 2020 139 ANITA PTIČEK SIROČIĆ, STANISLAV KURAJICA, DRAGANA DOGANČIĆ & NIKOLINA FIŠTER Petersen, G. W., Chesters, G. & G. B. Lee, 1966: Quan- titative determination of calcite and dolomite in soils.-Journal of Soil Science, 17, 328–338. http:// doi.org/10.1111/j.1365-2389.1966.tb01477.x Ponnusamy, V., Ramasamy, V. & P. Rajkumar, 2009: Depth wise analysis of recently excavated Vellar river sediments through FTIR and XRD studies.- Indian Journal of Physics, 83, 9, 1295–1308. http:// doi.org/10.1007/s12648-009-0110-3 Popović, S., Srdoč, D. & S. Grgić, 1986: Investigation of Lake Sediments and Tufa in the National Park Plit- vice by X-ray Diffraction and Optical Microscopy.- Zbornik 5. skupa sedimentologa Jugoslavije, Brioni 2.-5.06. 1986. Hrvatsko geološko društvo, pp. 140- 142, Zagreb. Proust, D., Eymer, J.P. & D. Beaufort, 1986: Supergene vermiculization of magnesian chlorite: Iron and magnesium removal processes.- Clays and Clay Minerals, 34, 572 580. Quirk, J.P., 1996: Interparticle forces: a basis for the in- terpretation of soil physical behavior.- Advances in Agronomy, 53, 121–183. Romanić Herceg, S., Kljaković – Gašpić, Z., Bituh, T., Žužul, S., Dvoršćak, M., Fingler, S., Jurasović, J., Klinčić, D., Marović, G., Orct, T., Rinkovec J. & S. Stipičević, 2016: The impact of multiple anthropo- genic contaminants on the terrestrial environment of the Plitvice Lakes National Park, Croatia.- En- vironmental Monitoring and Assessment, 188, 1, 1–16. https://doi.org/10.1007/s10661-015-5030-4 Socrates, G., 2001: Infrared and Raman characteristic group frequencies.- John Wiley and Sons Ltd, pp. 366, Chichester. https://doi.org/10.1002/jrs.1238 Srdoč, D., Obelić, B., Horvatinčić, N., Krajcar Bronić, I., Marčenko, E., Merkt, S., Wong, H. & A. Sliepčević, 1986: Radiocarbon dating of lake sediments from two karstic lakes in Yugoslavia.- Radiocar- bon, 28, 2A, 495-502. https://doi.org/10.1017/ S0033822200007633 Sremac, J., Božičević S. & I. Marković, 2012: Plitvice Lakes National Park (Central Croatia) – more than 50 years of continuos monitoring of natural and hu- man influence.- European Geologyst, 34, 12-16. Vrbek, B., 2005: Quality of precipitation and soil solu- tion in the national parks “Plitvice lakes” , “Northern Velebit” and “Risnjak” .- Radovi, 40, 1, 19-30. Zaharescu, D. G., Hooda, P. S., Soler, A. P., Fernandez, J. & C. I. Burghelea, 2009: Trace metals and their source in the catchment of the high altitude Lake Respomuso, Central Pyrenees.- Science of the To- tal Environment, 407, 11, 3546–3553. https://doi. org/10.1016/j.scitotenv.2009.02.026 ACTA CARSOLOGICA 49/1 – 2020 140