Springs with active calcium carbonate precipitation in the Polish part of the Tatra Mountains Agata Smieja 1, Beata Smieja-Król 2 1W. Szafer Institute of Botany, Polish Academy of Sciences, e-mail: [email protected] 2 Faculty of Earth Sciences, University of Silesia, e-mail: [email protected] ABSTRACT During the field work carried out in the years 2002-2006 over the floral composition in 340 water-springs in the Tatra National Park (TNP) eight springs with calcium carbonate precipitation were detected. Eight springs drain water away from carbonate rocks in three areas generally: Kopieniec slope of Olczyska Valley, lower parts of Lejowa Valley and in Ko ścieliska Valley. Two types of spring CaCO 3 accumulation were identified relatively to intensity of the process and stability of the precipitation products. The calcifying 2+ – springs represent the highest Ca , and HCO 3 ions concentrations among all investigated springs. In comparison with typical tufa depositing springs, the values appear to be rather low. KEY WORDS : carbonate precipitation, spring, the Polish Tatra Montains, tufa Introduction Calcareous tufas are, apart from cave accumulated as a fan at the foot of a rock wall. speleothems, the main sediments resulting In this site the precipitation ceased probably from decalcification of karstic water. Porous soon after the 13 – 14 century AD climatic tufa deposits form at or near the groundwater optimum (Alexandowicz, 1988). Another type outflow via the overall reaction: of freshwater calcium carbonate accumulations found in the Tatra Mts comprise slope breccias Ca 2+ + 2HCO - → CaCO ↓ + H O + CO ↑ 3 3 2 2 formed in Holocene or in the warm phases of Intensity of carbonate precipitation and Pleistocene. They are composed of locally deposition reveals close relationship with the derived carbonate rock fragments bound with local environment, and depends especially on calcite cement. The calcite cement forms a humidity and temperature conditions laminated crust on the rock clasts (Kota ński (Andrews, 2006). The optimal climatic 1958; Gradzi ński et al. , 2001). Their formation conditions for tufa deposition in the Carpathian in recent times is limited probably to one Mountains and its foreland prevailed during occurrence recorded by Kota ński (1971). Holocene Atlantic Phase when due to intense Recent calcareous tufa-forming springs are denudation significant amount of calcium rare in the Polish Tatra Mts, although actively carbonate was released (Pulina, 1974). A forming tufa deposits are known from many decline of active tufa formation has been sites in Southern Poland (Mastella, 2001; observed in all Europe over the last three Alexandrowicz, 2004). Alexandowicz (1988) thousand years, probably due to the climatic suggested that the present climatic conditions change (Goudie et al., 1993). prevailing in the Tatra Mts are too severe for In the Polish Tatra Mountains fossil tufa tufa accumulation. As to our knowledge, the from the Kraków Gorge was described, where only known springs actively accumulating plants encrustated by calcium carbonate calcite, were described in Lejowa Valley 220 Agata Smieja, Beata Smieja-Król (Głazek, 1965). Głazek (1965) found thin kode: 7220) are priority habitat types calcareous layers on rubbles, rocks and designated by European Union as particularly irregular oncolites of algae origin in three deserving intensive conservation care (Council small springs situated on the western slope of Directive 92/43/EEC). Their value is also this Valley. Another tufa forming spring accented in the Polish list of natural habitats located in the northern part of the Tatra Mts coming under protection (Dz.U. Nr 92, poz, was reported from Bobrowiecka Valley in 1029). Slovakia and was characterized by relatively In this work we present sites of active high temperatures of 14-16 ºC (Kowalski, precipitation of CaCO 3 found in the Tatra 1920). National Park (TNP) during a field work From the ecological point of view the carried out over vegetation in spring areas in calcareous crenal habitats with active calcium the years 2002-2006. A spring area is defined carbonate precipitation are very rare and here as a special habitat in and around the vulnerable phenomena with numerous rare and place where the groundwater comes to the endangered taxa (Wołejko 2004). “Petrifying surface, which is developed directly under the springs with tufa formation” (Natura 2000 water influence. Methods The water temperature and pH were atomic absorption spectroscopy (SOLAAR measured for each site in situ. Water was M6). Alkalinity was determined by titration. collected for laboratory measurements in Saturation indices (log IAP/K eq ) of the water selected springs in May and October 2006 and were calculated using a computer program, analyzed within three days of sampling. PHREEQC (Parkhurst, 1995). Calcium and magnesium were analyzed by Results and discussion Site description 340 spring areas were investigated in relation to floral composition as a main topic of the study carried out during the four years. 240 of the studied springs emerge from carbonate rocks. Calcium carbonate precipitates were detected in eight springs (Fig. 1) which drain away water from carbonate rocks generally in three areas: Kopieniec slopes in Olczyska Valley (Dolina Olczyska), lower parts of Lejowa Valley (Dolina Lejowa) and in Fig. 1. Localization of investigated springs in the Tatra Ko ścieliska Valley (Dolina Ko ścieliska), all National Park. I - sedimentary rocks (mainly carbonates), located within the lowest climatic-vegetation II - crystalline rocks, III - Pleistocene deposits (mainly zone (lower montane belt). The calcifying moraines), IV - Podhale flysch, V – state border, VI - the springs can be roughly divided into two types TNP boundary. Springs with active calcium carbonate precipitation in the Polish part of the Tatra Mts. 221 relating to intensity of the process and stability of the precipitation products. Table 1. Synthesis of the most important ecological features of carbonate precipitating springs Vegetation Water Spring Spring Altitude Slope cover in the Geological * Locality Coordinates temp. discharge o area (m a.s.l.) ( ) spring area basement (oC) (l/s) (m 2) (%) Lejowa N49 16 10.7 1 990 6.1 0.1-1 35 128 94 limestone Valley E19 50 30.6 Lejowa N49 15 49.9 2 1120 6.3 0.1-1 40 11 53 limestone Valley E19 50 12.0 Lejowa N49 15 32.6 3 1110 5.3 0.1-1 35 107 70 shale Valley E19 50 30.4 Staników N49 16 00.5 4 1210 8 0.1-1 10 94 90 limestone Gully E19 53 00.4 Mi ętusia N49 15 50.1 5 1185 9.4 0.1-1 25 27 50 limestone Valley, E19 52 51.2 Ko ścielis N49 15 20.7 clay, 6 ka 1124 5.2 0.1-10 30 56 62 E19 52 37.5 limestone Valley Olczyska N49 16 27.2 7 980 7.5 0.1-1 70 33 48 limestone Valley E20 00 04.5 Olczyska N49 16 31.3 clay, 8 1080 9 0-0.1 30 15 79 Valley E20 00 25.6 limestone * - numbers in the table correspond with numbers used in the map The first type is represented by two springs meters above the level of the Olczyski Stream with evidently long term accumulation of (Fig. 2). Discharge of water from the contact calcium carbonate. They detailed characteristic of a limestone and weathered rock ranges from are given below. The main ecological features 0.1 to 1 l/s. The upper part of the spring area is are summarized in Table 1. completely covered by dense carpet of moss Fig. 2. A general view on an intensively calcifying spring Fig. 3. Intensive CaCO 3 precipitation of Palustriella in Olczyska Valley (no 7). commuta mats (spring no 7). The first spring area is localized at the Palustriella commutata (species typical for bottom of Olczyska Valley on the right side of springs on carbonate bedrock). Because of the Olczyski Stream (number 7 in Table 1). It is high slope inclination in the lower part of the developed on a steep (about 70 o), rocky spring area, the bryophytes carpet is developed surface with the water emergence about seven to lesser extend and does not cover more than 222 Agata Smieja, Beata Smieja-Król 30 % of the spring area. The outflowing water together with small stones. Palustriella seeps slowly through the moss carpet and then commutata dominates in the upper part of the trickles down the rock. 5-10 cm thick porous area forming a dense carpet and higher plants moss-tufa deposit (Fig. 3) is forming under the like Festuca carpatica and Viola biflora moss which is growing upward while its lower inhabit the lower part. In the upper part, the parts become calcified. Due to the steep slope, calcite encrusted the lower, water soaked parts fist-size fragments of the highly porous moss- of the moss. The higher plants grow in tufa peel off and fall directly to the stream separate clusters within the lower part of the where they are washed away at higher water spring area and thin calcite crust develops levels, limiting tufa accumulation at this site. there not only on living plants but also on all The limestone bedrock is covered by a available surfaces present within the spring laminated tufa-crust up to 0.5 cm thick (Fig. 4) area like pebbles, dead leaves, twigs, etc. in the lower part of the spring area. Loose fragments of moss-tufa were also seen. Fig. 4. Carbonate crust on limestone rock from the lower Fig. 6. Gothic arch calcite crystals on a moss branch part of the spring in Olczyska Valley (no 7). (spring no 8). Fig. 5 . SEM photomicrograph of Palustriella commutata Fig. 7. Twinned calcite crystals on a moss leaf (spring encrusted by CaCO 3 (spring no 8). no 8). Calcite precipitation of similar intensity as After about 10 meters the spring waters flow the one described above was detected within a down to a nearby periodic stream.