Non-Rainfall Moisture Activates Fungal Decomposition of Surface Litter in the Namib Sand Sea

A mesophilic Ascomycete fungal community plays a crucial role in the decomposition of surface litter in the hyper-arid Namib Sand Sea, despite minimal rainfall (0-17 mm annually). These fungi respond rapidly to non-rainfall moisture sources like fog and dew, which occur every 3 days on average. Key traits enabling their survival include darkly-pigmented hyphae, a broad thermal range including low temperatures during fog events, and resilience to extreme desiccation and UV radiation (up to 50°C for five hours). The fungi significantly reduce the carbon-to-nitrogen (C/N) ratio of litter, making it more palatable for detritivores like termites. This discovery challenges the long-held assumption that detritivores alone drive decomposition in this ecosystem and underscores the importance of fungal activity in energy flow and biogeochemical cycling, with potential implications for climate change impacts on precipitation, dew, and fog regimes.

Jacobson, K., van Diepeningen, A., Evans, S., Fritts, R., Gemmel, P., Marsho, C., Seely, M., Wenndt, A., Yang, X., & Jacobson, P. (2015). Non-Rainfall Moisture Activates Fungal Decomposition of Surface Litter in the Namib Sand Sea. Plos One, 10(5), e0126977. https://doi.org/10.1371/journal.pone.0126977