Abstract

Rare Pacific coast fog ecosystems are under threat from climate change and local factors. Although coastal fog is known to affect soil properties and microbial diversity, few studies on the Pacific coast have examined the specific microbiomes associated with these ecosystems. We evaluated the effects of coastal fog on the physicochemical, mineralogical, and microbiological properties of bare soils (vegetation-free) and bulk soils (surrounding plant roots) from different altitudes in the Morro Moreno National Park (MMNP) in the Antofagasta region, Chile. We found that the temperature and relative humidity of the soil varied temporally (daily) and spatially (with altitude). We detected that soil organic matter and organic phosphorus content tended to increase with altitude, whereas the pH, electrical conductivity, and total phosphorus decreased. Our results showed that coastal fog could induce physical weathering below 300 masl and chemical weathering at the intermediate altitudes of similar to 400-600 masl. The biodiversity of bacteria and fungi increased considerably above 400 masl. Actinobacteria and Bacteroidetes dominated the bacteria in bare soil, and Bacteroidetes dominated the bulk soil communities at all altitudes. Ascomycota and Basidiomycota dominated the fungal community in both soil types. Moreover, the electrical conductivity and CaO content appear to be more closely associated with microbial communities from lower altitudes. In addition, the organic carbon content, humidity, and weathering index 2 (WI2) isolated some communities at 500 and 600 masl. The microbiological diversity reported in this work reflects the variable and different microbial niches comprising the MMNP environment. Linkages between soil property and microbial variations with altitude within this Northern Chilean coastal fog ecosystem were elucidated. This novel scientific knowledge contributes to global network strategies for fog ecosystem conservation, which aim to preserve the microbial niches and diversity in such soils.