The Tatra lakes comprise approximately 200 bodies of water, excluding smaller and seasonal lakes, located within the Tatra Mountains. Of these, around 40 lakes are situated in the Polish Tatras, while the remainder are found on the Slovak side of the range. They are known for their clear waters and scenic surroundings, making them popular destinations for outdoor activities such as hiking and photography.
In local vernacular, these lakes are traditionally referred to as "ponds", a term that is also reflected in various forms of literature, including scientific studies. The Tatra lakes play an important ecological role, supporting a range of flora and fauna, some of which are unique to the region. They contribute significantly to the natural heritage of the Tatra Mountains, attracting visitors interested in both recreation and nature conservation.
Origins Most of the ponds are located at elevations above 1,600 meters, primarily in the High Tatras, which is closely related to their origin. They are mainly of glacial origin, as glaciers significantly reshaped the landscape in the High Tatras, much more so than in the Western Tatras. These are mostly tarns, filling cirques, such as Czarny Staw pod Rysami or . Moraine-dammed lakes tend to be smaller and shallower. They formed in depressions dammed by lateral moraines () or terminal moraines (). Morskie Oko and are cirque-moraine lakes, located in deepened glacial valleys, closed by rock thresholds upon which terminal moraine ridges settled. There are also kettle lakes that fill depressions left by so-called dead ice blocks. An example is the large Štrbské pleso or the small . Smaller ponds, like or , fill depressions between piles of boulders and scree, and their origins are often mixed. , , and fill hollows of roche moutonnée troughs carved by glaciers.
There are a few small water bodies of different origins. These include karst lakes filling sinkholes (, ), overflow ponds (e.g., in the expansions of ), and ponds in ridge hollows (e.g., a pond on the Kasne pass). Additionally, there are about a dozen artificial lakes created by humans. Among these are , Nowe Morskie Oko near , and water reservoirs on (below Nosal and in ).
Classification of lakes The Tatra lakes have historically been classified based on thermal characteristics and, more recently, based on ice cover duration and morphometric features. classified the Tatra lakes into 7 groups:
large submontane reservoirs (up to 1,400 meters above sea level) with surfaces free of ice for at least 6 months a year, characterized by low transparency; shallow ponds and marshes (from 1,400 to 1,450 meters above sea level) characterized by significant temperature fluctuations in summer (from 4°C to 22°C); shallow ponds at between 1,450 and 1,700 meters above sea level with considerable temperature fluctuations in summer (from 4°C to 17°C); deep lakes at between 1,500 and 1,800 meters above sea level whose surfaces are ice-free for 3 to 5 months, with summer temperatures of between 8°C and 14°C; shallow lakes at between 1,700 and 1,900 meters above sea level with summer temperatures of between 8°C and 14°C; high altitude cold lakes (from 1,800 to 2,000 meters above sea level) whose surfaces are ice-free for less than 3 months, with summer temperatures below 8°C; frozen lakes located at between 2,050 and 2,180 meters above sea level, with summer temperatures not exceeding 5°C, and surfaces rarely free of ice; in some years, they remain covered with ice all year round.
Classification based on Ice Cover Duration (2020) A more recent classification of Tatra lakes, encompassing 50 bodies of water with an area greater than 1 hectare, was developed using the Wrocław taxonomy method. This classification objectively grouped lakes into internally homogenous classes based on six features: altitude, volume, potential incoming solar radiation (PISR), and the number of days with ice cover over three subsequent seasons (2014/2015, 2015/2016, and 2016/2017).
Based on the study, the 50 largest lakes were divided into seven resulting groups: small and shaded lakes of the alpine and subnival zones. This group is situated at altitudes between 2040 and 2057 m asl and is characterized by the longest duration of ice cover (average of 209 days) and the smallest average potential solar radiation. small and medium-sized lakes in the upper subalpine, alpine, and subnival zones. These lakes are typically located on the southern side of the main ridge. They have a long ice cover duration, which was about 16 days shorter on average than that of Class 1 lakes in the study seasons. small and medium-sized, insolated lakes situated in the upper part of the subalpine zone and the lower part of the alpine zone. This group is distinguished by the highest insolation and a very homogeneous ice cover duration, which was 22 days shorter on average than Class 2 lakes. medium-large, insolated lakes situated in the upper section of the subalpine zone and in the lower section of the alpine zone. These are much larger than Class 3 lakes in terms of area and volume, with an ice cover duration fluctuating between 162 and 174 days. small lakes in the area of the upper tree line and in the lower part of the subalpine zone. These lakes are situated at relatively low altitudes (1546 m to 1751 m asl), are generally small and shallow, and are characterized by high average monthly potential insolation. lakes not similar to each other (14 single-item sets). These lakes show some similarity to groups 2-5, but their individual characteristics mean they do not fit cleanly into a homogenous class. large lakes (>10 ha). This group includes all lakes with a surface area exceeding 10 ha (8 lakes in total). The predominant feature of these unclassified lakes is their large volume, which typically leads to a shorter duration of their ice cover. The largest lakes, such as Wielki Staw Polski and Morskie Oko, fall into this category.
Characteristics Tatra lakes are surface-fed by rain and meltwater, streams, and underground springs. The water levels in the ponds are generally stable, with the surface level fluctuating by only a few dozen centimeters. The highest levels occur during spring thaws, while the lowest levels are observed in autumn and winter. Water levels also rise after heavy rainfall, typically with a one-day delay. Some ponds give rise to streams, such as , which flows out of , and , which originates from . Some ponds, like or , are seasonal and often dry up during the summer months.
Most of the Tatra lakes are characterized by very high transparency. The highest transparency (measured by the visibility of a submerged white disk) is found in high-altitude tarns. Record transparency has been recorded in Veľké Hincovo pleso (19 meters), in Czarny Staw pod Rysami (from 16.5 to 17.5 meters), and in Morskie Oko (12 meters). Such high transparency is related to the very low organic life in these lakes, the absence of plankton, and the minimal presence of suspended particles. The littoral zone is either absent or poorly developed. The bottom sediments are highly mineralized and low in organic compounds, particularly nitrogen compounds. This is also one of the reasons for the low abundance of plankton in these lakes. The water in these lakes is cold and highly oxygenated, and they are classified as extremely oligotrophic. Lower-altitude moraine ponds, like Smreczyński Staw and Toporowe Stawy, which have richer organic life, are much less transparent (around 2 meters). High-altitude, deep, and nutrient-poor Tatra lakes, when viewed from a distance, appear sapphire blue. Slightly lower lakes, such as Morskie Oko, appear blue with an emerald hue, while Smreczyński Staw has a brownish color. However, these colors are observed only in the shallower water layers; in deep lakes, the water appears black due to the absorption and scattering of light, which prevents it from penetrating to great depths. When observing a lake from above, different shades can be seen depending on the depth of the bottom. owes its color to the cyanobacteria Pleurocapsa aurantica, which stains the stones on the lakebed a reddish-brown color.
Temperature measurements in the ponds show the existence of distinct water layers with a sharp temperature drop, known as a thermocline. The living conditions for aquatic organisms significantly depend on their location relative to the thermocline. The formation of a thermocline is related to the great depth of the lakes and the high mountain walls, which provide protection from the wind that stirs up waves. A measurement conducted on 2 August 1937 at Morskie Oko revealed that the well-mixed upper water layer, stirred by waves, was only 3 meters thick with a temperature of 12.1°C. From the surface to a depth of 10 meters, the temperature dropped by almost 1°C per meter; between 10 and 20 meters, it decreased much more slowly (around 0.25°C per meter). Below 20 meters, all the way to the bottom, the temperature remained constant at around 4°C. Surface water temperatures in the summer fluctuate differently in various ponds. For example, in Niżni Staw Toporowy, they range from 10.5°C to 21.5°C, in Morskie Oko from 9.4°C to 21.5°C, and in Czarny Staw pod Rysami from 7°C to 11.5°C.
Morphometric features
Among the permanent ponds, the lowest one is , while the highest is , both located in the Slovak Tatra Mountains. Some experts believe that the small permanent water bodies known as situated above 2,200 meters, should hold the record, but they are often omitted from most maps. In the Polish Tatra Mountains, the lowest lake is Toporowy Staw Niżni (1,089 m), and the highest is (2,070 m).
Compared to the lowland lakes of Poland, Tatra lakes have a small surface area, but some of them are remarkably deep, which is rare among lowland lakes. The largest lakes by surface area are located on the Polish side of the Tatras: Morskie Oko and Wielki Staw Polski. Depending on the measurement, one or the other of these lakes may hold the surface area record. The third-largest by surface area is Czarny Staw pod Rysami. The deepest lake in the Tatras is Wielki Staw Polski (79.3 meters), which is also the third-deepest lake in Poland. Across the entire Tatra range, 8 lakes have a surface area of more than 10 hectares (5 of which are in the Polish Tatras), while 49 lakes are larger than 1 hectare, with 11 of these located in the Polish Tatras. The largest group of lakes is the , with 27 lakes in a single valley.
Tatra lakes generally have a rounded shape, with short shorelines, and deeply indented bays are rare. Small islands are found in only a few lakes. These islands formed from masses of scree that slid into the lake (e.g., , ) or are roche moutonnées (rock outcrops) surrounded by water (e.g., , Kurtkowiec). Kurtkowiec contains Poland's highest island (1,689 m). Typically, the shores of the lakes are steep and descend quickly into the depths. The bottoms of larger lakes are usually flat (e.g., in Wielki Staw Polski, 14.4% of the lake bottom is below 70 meters) and muddy; larger boulders are generally found near the rocky walls. The shape, surface area, and depth of the lakes are continuously changing, as these bodies of water are being filled with scree from the steep slopes and sediments carried by streams flowing into them. Some lakes have already disappeared entirely, such as Lejkowy Staw. The current was once a large lake, which gradually filled with rock debris from the surrounding slopes. Lower-altitude ponds are shrinking due to progressive peat formation.
Largest lakes in the Tatra Mountains