The experts stated that karst is a terrain or landscape that has a special hydrological cycle as a result of the development of carbonate rocks (limestone and soluble rocks which have a good secondary porosity). In other words, karst is an area or region consisting of limestone which is characterized by a high level of running. Aside from that, there are also basins, bumps, irregular rocky hills, and underground flows and caves. (Also read: Marine Sediment Rocks: Definition, Types, and Examples).
The process of forming karst is influenced by two determinants, namely the controlling factor which includes soluble rocks, rainfall, and rocks exposed to the water circulation height and driving factors which include temperature and land cover. Both of these factors influence the terrain morphology or karst landscape. Rocks containing high levels of CaCO3 will dissolve easily; high rainfall will form the morphology of endokarst and exokarst. The appearance of exocarsts is doline, uvala, polje, karren, and endokarst appearance in the form of caves. (Also read: Epeirogenic Motion: Definition, Types, and Examples).
Based on the understanding of the karst mentioned above, the karst lake is a lake formed in the area of limestone which undergoes dissolution so that it forms a negative land or is below the average surface area of the local area. Karst lake which has a small diameter and surrounding area is called doline and karst lake which has a large circumference and diameter called uvala.
Characteristics of Karst Lake
Like most other lakes, karst lakes have water. However, if you pay close attention to the karst lake, there is no visible flow of water in and out. Karst lake water often shrinks, arises again, and nothing at all depends on the season.
Thus, karst lakes are often called seasonal lakes. Furthermore, in addition to the season, the presence or absence of water discharge in the karst lake is caused by the presence of karst caves that are below the surface of the lake. Water from the karst lake is filled with a source of water below the surface and dried by shallow holes below the lake’s surface. Another reason is that karst lakes are part of the existence of underground water sources and the surface of the lake is the increasing volume of water from the water source. In addition, karst lakes have several characteristics that are influenced by the karst region itself, which include:
- Contains carbonate rocks;
- Dominated by limestone;
- The types of soil that exist are in the form of terarosa;
- Textured clay;
- Has a medium reddish color;
- Consists of doline and uvala;
- Has a stable water discharge;
- Plays as a water reservoir; and
- Has very clear water quality
Example of Karst Lake
Karst areas are scattered throughout the surface of the Earth and in each location or country, there are several karst lakes formed from weathering of the karst rocks. Here are some examples of karst lakes that exist throughout the world, namely:
- Doline Lake in Gunung Kidul Regency in Yogyakarta, Indonesia.
- Ayamaru Lake in the Sorong area, West Papua Province, Indonesia. This lake consists of small lakes, namely Jow, Semitu, and Yate. The lake has an area of about 980 hectares with a depth of up to 6 meters.
- Juessee and Bauerngraben Lakes in the southern part of the Karst Harz Mountains and Eichner See lakes in southern Germany.
- Otjikoto Lake in Namibia, Africa.
- Der Cenote Sagrado Lake on the Yucatan Peninsula, Mexico.
- Cerkinsko Jezero Lake in Slovenia.
- Limni Loannion Lake or Pamvotis Lake and Limni Stymphalia Lake in Greece.
- Glenmaddy Lake, Turloughmore Lake, and Carran Turlough Lake in Ireland.
From the explanation above, the existence of karst lakes in some parts of the world is also one of the locations of geopark or geotourism, because the characteristics of karst lakes are different from the lakes in general. This is supported by the existence of karst lakes located in the karst region so that the reliefs or sightings of the base of the karst lake in shrinking water are the main attraction for tourists and researchers to know and observe the biological life that exists in the karst lake.
For instance, in the Ayamaru Lake in Sorong, it has biodiversity, namely a typical Papuan fish species. One of the endemic fish in the lake is a fish species of Boanemani Melanotaenia known as Rainbow Fish. In addition, karst lakes that exist in Indonesia generally have not been developed so much because of the location of the steep and uneven karst region which makes it difficult to develop the area.
In addition, erratic discharge and volume of water make it difficult for the karst base to be developed or converted. However, if possible, the development of karst lakes can be used as ponds or fishery ponds by using karamba or can also be used as a location for power plants with lake water strength.
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Nature is indeed a mystery to anyone. However, everything can be learned through science and research. Hope this can improve your insight about our amazing nature.