Caves and karst are home to many of the world’s most diverse, important and rare ecosystems, supporting ecological diversity above and below the ground, yet it is estimated that only 10% of the caves that are enterable have so far been explored.
Geologically, they are fascinating. Caves act as traps for sediment, accumulating various inorganic and organic materials. Study of these sediments provides information on global climatic changes, helping to uncover the recondite climatic shifts of the past, and to help forecast future climatic processes. Geologists analysing the stable isotopes in ‘speleothems’ (mineral deposits formed in caves by flowing, dripping, ponded, or seeping water) can pinpoint ancient temperatures from oxygen trapped in crystals. The types of vegetation that grew above the cave can also be mapped using ancient pollen trapped within the cave.
Karst is a type of landscape that covers 20 per cent of the world’s land surface. It is created by the dissolution of limestone bedrock. Karst aquifers provide an estimated 10 per cent of the world’s drinking water, comprising the largest wells and springs on Earth. Yet, for all their expansiveness, they are the most complex and least understood of all water supplies. They are often able to rapidly transmit pathogens and chemicals tens of kilometres, undetected to vital human and ecological water sources.
Caves are becoming more important research sites for pressing global health challenges. Through overuse, antibiotics have increased the proportion of microbes that naturally carry genes for antibiotic resistance, leading to a rise in antibiotic-resistant infections across the world. Microbes in caves however, have been occluded from human-interference allowing researchers to study how natural resistance to antibiotics evolves. Due to the nutrient scarcity in caves, microbes have also evolved a greater degree of genetic diversity, meaning they are hotbeds for the discovery of novel antibiotics.
Caves have been the backdrop for many of the world’s paleontological and archaeological breakthroughs. When caves are not hydrologically active, animals and plants that have fallen or been carried into a cave remain undisturbed by erosion that would normally destroy them on the surface.
It is estimated that just 10 per cent of the cave systems deemed enterable have actually been explored. Ninety per cent may yield secrets of unknown value to science.
This year is the perfect year to build your interest in caves – 2021 is the International Year of Caves and Karst, with a host of virtual events taking place. ‘Explore, Understand, Protect’ is the year’s motto, and to help you do just that, the International Union of Speleology in conjunction with the British Cave Research Association will be running a Monday night lecture at the Royal Geographical Society on 20th September. The evening will be full of new information on cave science, conservation, cave rescue and discovery, for all attendees and members of the RGS.