Approximately 15 % to 20 % of Earth's ice-free land consists of karst landscapes. Despite this, we are still in the dark when it comes to our knowledge of subterranean ecosystem.
Karst landscapes occur predominantly in areas with sedimentary rock, mainly limestone (chalk). Rainwater, which is naturally slightly acid, dissolves the soluble bedrock, and over time karst formations such as caves, sinkholes and underground rivers are created. The weathering process is very slow: it may take up to 100,000 years before the percolating water has created a cave large enough to fit a human.
The name 'Karst' originates from a region on the Dalmatian coast in the Mediterranean but nowadays the name is used to describe similar hydrogeological features around the world. Characteristic to a karst landscape is the absence of surface water such as streams and lakes. Karst formations vary in size and extent from small sinkholes to far-reaching networks of interconnected caves. Many caves are partially or completely filled with water, which further contributes to their inaccessibility. Taking into consideration how inhospitable the environment is to humans, it is easy to understand, why our knowledge of subterranean ecosystems is so limited.
Subterranean ecology is in many ways the ecology of the extremes. Caves tend to be dark, humid, and lack diurnal and seasonal temperature cycles. Such conditions are relatively stable compared to the disturbances that most other ecosystems experience. Some of the karst formations have remained largely unchanged for thousands, if not even millions, of years.
Despite their location below the surface, however, they are not void of life. Several karst ecosystems are considered important for their biodiversity, both below and above the ground. Thanks to their complex physical and biological characteristics, karst landscapes exhibit high levels of adaptation and endemism. They may prove to be an important source for discovering previously unknown animal species, microbe communities and bacteria.
Karst landscapes also contain aquifers and thereby play an important role in the water cycle. In fact, the slow percolation of water that creates the karst formations is a vital part of the process that provides clean ground water. It is estimated that a quarter of the world's human population obtain their water from karst aquifers, despite their being susceptible to groundwater contamination and sinkhole collapse. Subterranean ecosystems and aquifer’s fragile nature, as well as the unique diversity they hold and our dependance on them, warrant careful management.
Written by: Tina Sommarstorm
Provita Oct 10, 2017