Microbial cellulose degradation and seasonal controls on the biogeochemical cycling of cobalt, nickel and manganese in tropical serpentine soils

Serpentine soils are rich in metals such as Co, Ni and Mn, due to their ultramafic origin. They are actively formed in the Santa Elena Peninsula in Costa Rica, resulting in the development of local serpentine ecosystems where rainfall patterns can generate redox fluctuations in the soils, potentially affecting microbially-mediated processes. However, the role of natural carbon sources, such as cellulose from plant matter, in the natural biogeochemical cycling of Co is still unexplored, and the impact of seasonal precipitation on the biogeochemical cycles of metals have not been tested for tropical serpentine soils. The aim of this study was to characterise the natural biogeochemical cycling of Co, Ni and Mn in the serpentine soils of the Santa Elena Peninsula, considering the influence of cellulose and seasonal rainfall.