Seasonal variation in fungal biomass : the effects of soil temperature and moisture in a boreal forest

Abstract: Climate change involves a series of events promoted by elevated levels of atmospheric CO2, such as increased temperature and changes in seasonal precipitation patterns, soil temperature, moisture and nutrient availability. Soils in boreal forests are often well-drained and not underlain by permafrost, which makes boreal forests susceptible to droughts. Models predict a 7.4% decrease in soil moisture per degree Celsius of warming in Europe, however, the effect of changes in seasonal patterns on fungi is still unclear. Whether and how changes in soil temperature and moisture will affect fungal biomass is still incoherent. In this study, I tested monthly biomass variation over a whole year in order to determine if seasonal changes in soil temperature and moisture, such as drought, had an effect on biomass, and whether fungal communities in different soil fertility have different responses to disturbances in seasonal patterns. I used DNA extracts from samples collected each month for a whole year. I amplified the ITS region using qPCR and quantified ITS copy number, which were then recalculated to get an estimation of fungal biomass in the sampled soil. Soil temperature and moisture had been measured throughout the year and daily measures were recalculated to monthly averages. This study demonstrates the temporal variation of fungal biomass and how biomass depends on the interaction between temperature and moisture in the soil. Further it shows how fungi in soils of different fertility levels are affected by seasonal changes and extreme weathers such as drought.