Cave diving

Cave diving is a method of exploring underground bodies of water. It combines elements of scuba diving and spelunking and presents significant challenges and risks. It requires very specific equipment and a great deal of specialized training. Cave divers have to account for limited light and visibility, unstable rock or ice, strong currents, and lack of direct access to the surface. Common sites for cave diving are found in South Africa, Zimbabwe, Australia, Florida, the Bahamas, and Italy.

Cave diving can serve both recreational and scientific purposes. The environment of underwater caves has not been thoroughly explored by humans, and it contains many unique life forms and traits. With protection from light, wind, precipitation, and larger animals, these locations can remain undisturbed for long periods. The environments preserve their contents extremely effectively, making them very interesting to archaeologists and other scientists.

Background

By the eighteenth century, the concept of cave exploration—or spelunking—was popular. Explorers were drawn to the mystery and the challenge, and academics were interested in what made up cave ecosystems. Bodies of water often marked the boundaries of spelunking expeditions. The first recorded cave dive occurred in 1773, when a man known as Mr. Day attempted to cross an underwater passage using only his lung capacity. He nearly drowned and needed to be rescued. In 1922, Norbert Casteret successfully navigated through an aquatic section of a cave. When he found the surface on the other side, he discovered a whole network of caves. Subsequent explorers found significant artifacts in this area, proving that cave diving could provide value beyond thrill and challenge.

In 1943, famed marine biologist Jacques Cousteau cocreated the Aqua-Lung. This changed diving and underwater exploration forever, allowing divers to remain beneath the surface for significantly longer periods and reach much greater depths. Initially, the preferred method of navigating beneath the water was to walk along the ground or floor. Doing so, divers did not have to worry about managing their buoyancy. Changing depths too quickly could have strong effects on the human body, and this method of navigation kept any depth changes to a minimum. Later in the 1940s, however, Cousteau's team popularized the idea that swimming with fins worn on the feet was the far superior method of underwater travel. While there were more factors to consider and manage, divers swimming with fins were much more mobile and could explore their environments more fully.

These developments were massive boosts to diving. Cave diving enjoyed particularly strong benefits. Many underground bodies of water were simply too dangerous to navigate without supplemental oxygen. While not as essential, swimming with fins proved to be far more useful for exploring caves. Most water in caves contains silt and contact with a solid surface is likely to stir it up, reducing already poor visibility. Furthermore, the silt lingers in many caves, taking a great deal of time to settle back down.

Overview

By the mid-twentieth century, the technology existed for cave diving. However, the activity was still dangerous and required a lot of knowledge to be done safely. The most significant safety factor is that, unlike in open water, a diver cannot rise straight to the surface in the event of some type of emergency or equipment failure. Aspiring cave divers initially train for scuba-diving certification, then for cavern diving. Cavern diving takes place in front of a cave entrance, where bodies of water are still relatively open and divers have direct access to the surface. Then they move on to cave diving, which can involve long, narrow tunnels and hundreds of yards between locations with accessible air.

Even if divers avoid disturbing silt, the environments they explore can involve partial or total darkness. Experienced cave divers bring multiple waterproof lights with them. They also make use of lines to avoid getting lost and to help them find their way back to their entry point. When possible, cave divers set out with at least one partner, but the tight spaces they navigate can force them to travel alone.

Diving in ice caves provides a unique location to experience, but also comes with its own set of challenges. Divers must be prepared for very low water temperatures, which could put their health at risk. Cave-ins are also more likely when the caves are made of ice.

As technology improved, serious cave divers came to prefer rebreathers to traditional Aqua-Lungs. Rebreathers use the carbon dioxide exhaled by the body and draw oxygen from it, effectively recycling the air that the diver breathes. This has the advantage of allowing divers to wear smaller tanks, which is essential when squeezing through tight spaces in underwater caves. Rebreathers also produce fewer bubbles than the older scuba gear releases. Cutting down on bubbles is both helpful to divers—it prevents them from disturbing silt and clouding their vision—and welcome on scientific expeditions, since it cuts down on human disturbances in possibly fragile ecosystems.

Often, the development of cave diving has intersected with that of space exploration. The rebreather is one example, as its design was based on the same principle used in astronauts' space suits. Scientists have also used digital mapping devices—initially developed by aerospace engineers—to map the layout of caves. The devices have been tested and used in Earth caves, and astronomers intend to use them on Jupiter's moon Europa someday. The information biologists learn during cave dives is important to the search for alien life. The traits of life that can survive in the darkness and isolation of caves are traits astronomers search for when seeking life on other planets and moons.

Bibliography

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Kremer, William. "The Cave Divers Who Went Back for Their Friends." BBC, 9 May 2016, www.bbc.com/news/magazine-36097300. Accessed 25 Oct. 2017.

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Siber, Kate. "Cave Diving's Mysterious Allure—and Risks." National Geographic, 20 Oct. 2016, www.nationalgeographic.com/adventure/destinations/united-states/florida/two-divers-die-in-eagles-nest-cave/. Accessed 23 Oct. 2017.

"Things to Consider Before Taking Up a Cave Diving Course." Dive In, www.divein.com/articles/beginners-guide-to-cave-diving/. Accessed 23 Oct. 2017.

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