Underwater caves offer breath-taking natural wonders, such as the blue holes of the Caribbean, and incredible archaeological sites, like the art of Cosquer Cave in France (1). Submerged caves include a wide range of geological formations, including springs, siphons, flooded cavers, cave lakes, sumps, sinkholes, and cenotes (2).
Each of these categories was formed through different methods and the archaeology differs in each type. Nevertheless, caves offer some of the best conditions for preservation of archaeological material, such as organics, which do not often survive in dynamic marine environments or terrestrial sites.
Physical evidence of past cultures, in the form of artifacts or modifications of natural formations, is called material culture. Depending on the site conditions, this evidence can degrade naturally at varying rates, with submerged sites degrading far more rapidly than those on land. Over time, the cultural material often reaches equilibrium with its environment, where it stays in a suspended state if factors remain the same. However, on some sites artifacts continue to degrade until they disappear. Disintegration rates differ between each site, even those that appear similar, and depend on a wide range of factors. Some material culture can disappear in weeks, such as organics like soft tissue, or hundreds of years, like some ships’ timbers (3). Even when an artifact is heavily eroded, natural transformations that altered it can be identified. Through scientific experiments or computer programs, they are recordable and quantifiable, usually allowing for precise reconstructions.
Cultural transformations cannot always be identified. These transformations are those created by later cultures and include ancient salvage, modern salvage, dredging, looting, and archaeological excavations. Since these transformations cannot be measured and documented in the same way as natural phenomena, reconstruction is usually not possible unless the entire process is recorded, as done in archaeological excavations. When these transformations are left undocumented, such as looting or unpublished archaeological work, then there is a large gap in our knowledge of a site’s environment that is difficult to mitigate.
Disturbance of the equilibrium that protects cultural material is usually caused by cultural transformations. These are often accidental and subtle, such as dredging for coastal channels causing sediment several miles away to shift. Unfortunately, in caves it can be something as simple as a site being visited for the first time or untrained divers visiting a site and colliding with walls or stirring up sediment. These types of accidental disturbances to equilibrium do not often destroy a site; rather they reveal cultural material to natural transformations once again, allowing further eroding. There are several simple ways of protecting these sites for future visitors while gathering information about past cultures.
Documentation and stewardship, while providing public information, are the keys to preserving these sites. A thorough archaeological survey will document cultural material without removing anything, leaving artifacts in situ. It is important that artifacts that are disintegrating or are exposed and removed from equilibrium are documented before further erosion occurs. Stewardship allows cave experts, interested parties, or the public to access the cave, depending on the owner’s preference and level of site’s fragility. Preservation begins with cavers and cave divers, who can identify cultural material and notify CAIRN, National Speleological Society (NSS), Cave Research Foundation (CRF), National Cave and Karst Research Institute (NCKRI), or other groups. Discoveries are made by local cavers and cave divers, who are the vanguard of research. To protect caver propriety and favorite local caving spots, CAIRN has a policy of not disclosing cave locations, referring to caves by their location (i.e. SW MO #1). Ensuring that individuals who enter caves are knowledgeable about the damage they can cause to cultural material, natural formations, and the community, as well as themselves, is the most important way to prevent damage to site, similar to Carlsbad Caverns Nation Park’s policy on unqualified cavers entering Lechuguilla or Nation Association for Cave Diving (NACD) policy on unqualified divers entering certain submerged caves.
Since the multifaceted subject of archaeology and its subfields can be complex, outreach and education are key missions of CAIRN, who is working towards a collaborative relationship between many related scientific research communities. CAIRN representatives would be happy to spread the word of cave and archaeological stewardship. If you would like to arrange a guest speaker for a local organization, school, or event, please contact us.