14 September :An extraordinary underground world of caves and karst landscapes stretches across an estimated quarter of the Earth’s land surface. These environments serve as a major source of drinking water for billions of people, while also providing shelter for rich biodiversity and preserving important evidence of ancient human history.
To raise global awareness of these fragile underground ecosystems, UNESCO has designated September 13 as International Caves and Karst Day. The observance is being held for the first time this year. One of its key objectives is to highlight the importance of karst regions in understanding global landscapes, protecting groundwater resources and conserving biodiversity.
Caves are found across an estimated 15 to 25 percent of the world’s land area. Karst landscapes develop over long periods through chemical reactions between rainwater and mineral-rich rock. Groundwater aquifers in these regions supply water to approximately 16 percent of the global population. This has made caves and karst environments important centres for human settlement and the development of civilisations since ancient times.
The underground world is also highly significant for scientific research. Thousands of caves remain unexplored in various parts of the world, including Canada’s Rocky Mountains. Canadian researcher Derek Ford has played a pioneering role in cave studies. His research team has analysed underground formations and other evidence to investigate the history of ancient ice ages.
Mineral formations inside caves, known as speleothems, preserve valuable information about past climates. According to researcher John Pollack, understanding geography and geomorphology is essential to interpreting the Earth’s true form. Karst landscapes provide an important field for such research.
Canada’s Castleguard Cave is one of the country’s longest and most complex caves. Located beneath an icefield, the cave has been directly penetrated by ancient glacial ice. Despite its extreme environment, rare aquatic crustacean species have been found there.
Greg Horne, an official with Parks Canada, said cave landscapes may date back millions of years, while many structures on the Earth’s surface are comparatively young. Various parts of these underground landscapes continued to develop even after glaciers melted. Mineral deposits inside caves also provide important clues for investigating the history of climate change. Just as tree rings are used to determine the age of trees, layers and formations inside caves can help researchers reconstruct records of past rainfall.
Cave rocks may also preserve evidence of changes in the Earth’s magnetic field. By analysing iron oxide minerals, scientists can obtain information about changes in the direction of magnetic poles in the past.
However, communicating the importance of this underground world to the general public is not always easy. Extreme darkness, difficult access and hazardous conditions limit public entry into many caves. At the same time, cave ecosystems are highly sensitive, leading researchers and explorers to keep the locations of some sites confidential.
The pace of new cave discoveries has increased in recent years. British Columbia’s Bisaro Anima Cave has set a record as Canada’s deepest cave. The entrance to a vast cave discovered in Wells Gray Provincial Park has also attracted widespread interest on social media.
Various types of bacteria capable of surviving in extreme conditions have been discovered in remote caves. The antibiotic-resistant properties of some of these microorganisms could potentially contribute to addressing the global antibiotic crisis in the future.
Another important aspect of caves is their role in preserving human history. Archaeological excavations at Rats Nest Cave have uncovered various remains of ancient human civilisation. These include the remains of mammals dating back approximately 7,000 years and ancient stone tools.
Researchers say protecting caves and karst regions is essential for understanding past and present groundwater flows and climate change. They also stress the need to educate younger generations about karst science and the importance of groundwater. International cooperation and coordinated action are essential to protect these invaluable natural resources hidden beneath the Earth’s surface.
Sources: UNESCO and Canadian Geographic.