Abstract
Global changes, such as shifts in precipitation regimes and increased in atmospheric nitrogen (N) deposition can influence N cycling in the boreal forest, with uncertain but potentially important consequences for ecosystem functions such as productivity and the global carbon balance. In boreal forests, the understory vegetation is often dominated by feather mosses. The moss layer, also referred to as *bryosphere*, consists of living and dead mosses and is inhabited by a large diversity of organisms, including N-fixing cyanobacteria and decomposers, collectively comprising the moss food web. However, we know very little about the role of the moss food web in mediating how global changes influence N cycling in the bryosphere of boreal forests. In this project, we will test how shifts in precipitation and increases in N deposition affect the fixation of N by cyanobacteria on feather mosses, and the flux of N through the bryosphere. Further, we will explore how interactions in the moss food web drive N cycling, and how this affects productivity and carbon storage in the bryosphere. To do this, we will perform a series of experiments in which we will manipulate moss food web structure under different levels of precipitation and N deposition. We will use two dominant feather moss species as model ecosystems. Results from our project will improve our understanding of how food web interactions in the bryosphere contribute to the global carbon cycle.
Sweden