Biological Phosphorus Cycling in Arctic and Alpine Soils

Abstract

Organic phosphorus (P) is the predominant source of plant and microbial P in many arctic and alpine soils due to high moisture and low temperatures, which result in the accumulation of soil organic matter and P cycles dominated by biological processes. It has been hypothesized that the organic P accumulates in cold soils due to the inhibition of microbial activity by low temperatures. However, microbial activity has also been found to continue at low temperatures. Microbial biomass is one of the largest reservoirs of P in arctic and alpine soils, and a release of microbial P in the spring can be an important P flux. P availability in these soils is typically low during the growing season, but increases have been observed late in the growing season in arctic soils, probably due to root and microbial phosphatase activity. Fertilization studies in arctic and alpine ecosystems have had mixed results, with some plant communities typically responding more to P, whereas others are either nitrogen-limited or co-limited.