The moss microbiome: interactions between mosses and microorganisms

Main area:Ecology
Target group:Biology, Biochemistry
Educational level:Bachelor, Masters
Project description:

Mosses are important components of many ecosystems such as boreal and temperate forests, and arctic tundra. Here, they can cover up to 100% of the ground, contribute to ecosystem productivity and are hosts to a wide range of organisms. Yet, they are often overlooked. Therefore, we do not know much about how they interact with microorganism, and the basic processes, including decomposition, that occur within the moss carpet, and in decaying mosses. For instance, why do mosses decompose so slowly? Is it due to their low nitrogen (N) content, their high polyphenol content or their microbial associates (e.g. N-fixing cyanobacteria)? How do moss species, microbiome and ecosystem type affect moss decomposition? 

In this project, we will determine decomposition rates of mosses collected in different habitats (e.g. temperate and boreal forests), compare it with decomposition rates of soil and litter from the same collection sites, and assess which factors control moss decomposition (e.g. nutrient content, polyphenol content). Further, we will expose samples to different temperatures to identify the temperature dependence of decomposition. Concomitantly, we will study the microbiome composition using molecular methods. We will also link moss decomposition rates to the activity of N-fixing cyanobacteria that live on moss leaves. Their N fixation activity could affect moss decomposition rates due to changes in N availability within the moss carpet. 

Specific research questions that can be addressed in this project include:

·      Which physicochemical factors (e.g. nutrient content, polyphenol content) control moss decomposition?

·      How does moss species and microbiome type affect decomposition?

·      How do moss decomposition rates compare to decomposition of soil and litter?

·      Do decomposition rates differ between ecosystems with a different climate?

·      How sensitive is moss decomposition to different temperatures? And is the temperature sensitivity linked to the origin of the samples (different climates)?

·      How does N fixation, and thereby higher N content, affect moss decomposition?

·      Do mosses decompose faster when inoculated with “local” microorganisms compared to mosses inoculated with “non-local” microorganisms?


Flemming Ekelund and Kathrin Rousk

Methods used:Decomposition estimates, nutrient analyses, N fixation- and other gas measurements, phenol content, growth chamber experiments, field sampling, molecular analyses of microbiomes
Keywords:microbial ecology, DNA sequencing, decomposition, mosses, nitrogen fixation, climate change, microorganisms incl. cyanobacteria
Supervisor(s):  Flemming Ekelund and Kathrin Rousk;