Seasonal variation in the coupling of microbial activity and leaf litter decomposition in a boreal stream network

Most stream networks are characterised by spatial and temporal variability in the physico-chemical conditions that regulate microbial processing of particulate organic matter. How these patterns control turnover matter via altered activity leaf-associated microbes has rarely been studied high-latitude landscapes, particularly throughout long (i.e., up to 6 months) ice- snow-covered periods. We investigated development fungal biomass, enzyme activity, respiration, birch leaf litter decomposition from autumn early summer 11 nested streams a boreal catchment encompass gradient wetland (mire) cover. observed relatively low rates across network, despite differences key physical chemical variables (e.g. temperature, pH, dissolved carbon [DOC] concentrations) over time space. Microbial enzymatic respiration were positively related during stages c. 30% loss initial ash-free dry mass). Thereafter, variation was decoupled mass loss, as instead became DOC concentrations upstream mire (wetland) cover among streams. Our results suggest increase their reliance on external sources energy time. This switch resource use more evident with higher concentration, which landscapes is largely determined Hence, linked landscape configuration, or intensified land climate change, could affect how different used communities, consequences for overall cycling headwaters.