Global Peatland Microbiome Project

Photo Credit

USDA Forest Service photo by Louis Jamie Lamit.

Hudson Bay Lowlands, the second largest northern peatland complex in the world.

Peatlands represent only 3 to 5 percent of land surface but contribute substantially to ecosystem services. For example, peatlands sequester about 25 to 30 percent of soil organic carbon. Soil organic carbon is vulnerable to environmental changes, such as changes in water table, warming, and land use change. Uncovering the microbial communities in peatlands and understanding how they vary with climate will improve our knowledge of how peatlands cycle and store carbon.

The Global Peatland Microbiome Project is a multi-institution collaboration between scientists at the Northern Research Station, the Joint Genome Institute, the United States Geological Survey, Oak Ridge National Laboratory, Lakehead University, and Syracuse University that aims to improve our understanding of peatland microbes around the world.

Specific research questions of the Global Peatland Microbiome Project include:

• How do microbial communities in peatlands vary in response to changes in climate, such as warming and elevated carbon dioxide?
• How do water table levels and peatland plant communities interact to influence microbial communities?
• What poorly characterized microbes are commonly found in peatlands, and what can we learn about their function?

Key Findings

• Microbial communities differ across peatland classes, and the metabolic activity of microbial communities varies with latitude.
• Fungi are more sensitive to changes in plant community composition while bacteria and archaea are more sensitive to changes in the water table.
• Certain groups of methane-producing microbes are influenced by concentrations of nickel and copper in peatlands.
• Peat organic matter chemistry is sensitive to climate and land use change at a global scale.

Approach

The Global Peatland Microbiome Project investigates microbial communities in both natural peatland ecosystems across the globe and in peatland experiments that test the effects of changes in climate on microbes. Members of the global peatland research community provided samples of peat from hundreds of sites from all continents. Researchers use a specific region of genetic material (ribosomal DNA) to identify the microbes that they find in peat samples. They then compare the microbial communities found across peatlands around the world with environmental data to investigate why they are different and how these differences relate to climate change and influence carbon cycling.

Photo Credit

USDA Forest Service image by Louis Jamie Lamit.

Overview of peatland sampling sites in the Global Peatland Microbiome Project.

Two of the experiments that Global Peatland Microbiome Project researchers are studying include PEATcosm and SPRUCE. PEATcosm was a mesocosm study in Houghton, Michigan in which individual cubic meters of intact peatland are transferred to controlled environments where researchers manipulate the water table and plant communities. SPRUCE, or Spruce and Peatland Responses under Changing Environments, is a field experiment involving ten open-topped enclosures with varying degrees of warming and elevate carbon dioxide. Peat samples from both experiments have been analyzed for metagenome and meta-transcriptome analysis; this helped classify the genetic material in those samples as well as the RNA transcripts, which provides insights into the proteins that are synthesized.

On a subset of microbes that are common in the peatlands that the Global Peatland Microbiome Project is studying, but are not well characterized, researchers performed single-cell genome sequencing. This method produces a near-complete genome sequence of the microbe.

Expected Outcomes

• Catalog of microbes in peatlands around the world and a better understanding of how these communities change with climate change and other global change factors.  
• Full genome sequences of common microbes  
• A uniform set of data that can be used to compare peatlands around the world.