Royston Cave may seem an unlikely place for life to thrive, but its cool, damp and sheltered environment provides ideal conditions for a variety of microorganisms.
Fungi, bacteria and algae all live naturally within the cave, forming part of a small but fascinating underground ecosystem, however, some can contribute to the gradual deterioration of the chalk. As they grow, they can enlarge existing cracks, while chemical by-products produced during their life cycles may also affect the stone.
Much of the microbiological growth appears as black, brown or green patches on the cave walls. Some areas are difficult to distinguish from ordinary dirt, but growth is particularly noticeable along the line of figures beneath the carving of St Christopher.
Evidence of microorganisms has been recorded in the cave for many years. During the 1990s, growth became especially widespread after lighting changes led to the cave lights being left on for extended periods. This encouraged green algae to develop around the light fittings, especially in damp areas affected by flooding.
Surveys carried out in 2004 identified several species of fungi, including Penicillium chrysogenum, Aspergillus niger and Trichoderma viride, as well as green algae such as Protococcus. None are a risk to visitors.
Today, careful management of lighting helps to reduce the growth of algae and other light-dependent organisms. Chemical treatments are avoided wherever possible to protect both the cave’s delicate environment and the local water table. Together, these measures help preserve Royston Cave for future generations.
The 2026 public tour season has now come to a close. For group bookings and special events, visit: www.roystoncave.co.uk
By Emma, Royston Cave Manager
