Structure and Function of Mycorrhizal Mat Communities at the H. J. Andrews LTER Microbial Observatory

Oregon State University, Corvallis OR

Investigators

Abstract

A Microbial Observatories grant has been awarded to Drs. David Myrold, Peter Bottomley, Bruce Caldwell, Kermit Cromack, and Joseph Spatafora of Oregon State University to study the microbial communities of mycorrhizal mats associated with mature conifer stands in Oregon. The research sites will be located at the H. J. Andrews Experimental Forest, which is a Long-term Ecological Research site. Mycorrhizal mats can be seen with the naked eye and are formed by fungi that have a symbiotic relationship with tree roots: the fungus provide the tree with nutrients, such as nitrogen and phosphorus, and the tree supplies the fungus with sugars derived from photosynthesis. In addition, the mycorrhizal mats alter the soil environment and likely establish a unique microbial community that also alters the carbon and nutrient cycling activities of the soil microorganisms. The goals of this research are: (i) to identify the fungi, bacteria, and other microorganisms that are part of the mycorrhizal mat community, many of which may be new to science; and (ii) to determine the roles that these different microorganisms play in the functioning of this community. Modern methods, such as high volume DNA extraction and sequencing, will be combined with more traditional culturing and activity measurement techniques to gain insights into this unique microbial system. This research will enhance our understanding of the workings of coniferous forest ecosystems, which are important sources of biodiversity of plants and animals, potential sinks for atmospheric carbon dioxide, and economically important for timber production. Several graduate students will be trained in contemporary microbial ecology and the visible nature of the mycorrhizal mats will be used to introduce middle and high school teachers to the microbial world just outside their classrooms through annual training sessions.