Underwater archaeology does not always involve excavation, but when material is removed for detailed study, it is essential to have laboratory facilities available to preserve the artifacts. The miraculously well-preserved condition of objects is more apparent than real.
During lengthy immersion, artifacts react chemically with the water and sediments surrounding them. Sudden removal from their watery environment and exposure to air can set off a chain of chemical and physical reactions in the objects which could lead to their destruction.
Conservators are specialists who work with archaeologists to preserve artifacts for study and display. The conservation of objects takes much longer than their actual excavation, and the long-term care of a collection of excavated objects is expensive and time-consuming. Unless proper facilities and resources are available, it is often best to leave objects in their underwater environment. Conservators also work with archaeologists and site managers to monitor the condition of sites and artifacts left in place to preserve them for future generations.