The Department of Soil and Environmental Sciences is pleased to announce the inaugural Dale Cole Lecture in Soil Science (previously the Leo M. Walsh Distinguished Lecture in Soil Science) on Wednesday, April 30, at 3:30 p.m. in room 270 of the Soils Building. A reception will follow in the Jackson-Tanner Commons from 4:40–5:40 p.m. 

Jennifer Pett-Ridge, senior staff scientist at Lawrence Livermore National Laboratory, will present a lecture entitled “The Music of Soil: How Microbial Ecophysiology Shapes Persistence of Organic Carbon in Soil’s Many Habitats.” 

Abstract: Since the dawn of agriculture, cultivated soils have lost a vast amount of carbon to the atmosphere. To understand and promote the effects of soil microorganisms that lead to stable soil carbon, it is critical to understand how microbial ecophysiological traits are linked to soil organic matter formation, and how cross-kingdom interactions—involving bacteria, fungi, archaea, protists, microfauna and viruses—shape soil carbon availability and loss. This is particularly true in the soil surrounding plant roots, the ‘rhizosphere’. Stimulated by exudates and root decay, rhizosphere organisms (bacteria, archaea, fungi, fauna, and viruses) interact to move carbon from root tissue to surrounding soil, and ultimately regulate how soil carbon is stabilized. While the concepts of soil food webs are well established, a quantitative and mechanistic understanding of how networks of organisms control dynamics of soil organic matter (SOM) and respond to changing precipitation patterns is only recently emerging. While some bio-interactions may be mutually beneficial, many others are the proximal cause of microbial death and turnover, producing microbial ‘necromass’ that plays a critical role in the persistence of SOM. I will present evidence from studies where cross-kingdom responses to environmental drivers have follow-on effects for soil carbon—including shifts in resource availability around roots, fungal-bacterial interactions, and microbial community successional shifts during a post-drought wet-up. In all of these systems, stable isotope probing (SIP) helps us assess the active microbial and viral community. These studies suggest that cross-kingdom interactions, involving bacteria, fungi, archaea, protists, microfauna and viruses, shape carbon availability and loss pathways and are differentially influenced by both soil habitat (rhizosphere, detritusphere, bulk soil) and natural fluctuations in the physicochemical environment.

Made available by the generosity of Dale Cole and the Dale Cole Distinguished Lecture in Soil Science Fund.

For more information, contact Carol Duffy at (608) 262-0485 or cjduffy@wisc.edu.