Study aims to measure the impact of increased nutrients on soil microbial biodiversity

Grassland soil today experiences increased nutrient inputs, which have dramatic impacts on biodiversity. To help understand this issue, researchers at the University of Oklahoma are leading the American contribution to a global study that aims to measure the impact of increased nutrients on soil microbial biodiversity and the ecosystem-level functions for grasslands around the world.

Human activities are increasing the amount of biologically limiting nutrients, such nitrogen and phosphorus, flowing into ecosystems on every continent, and this increased nutrient supply is causing dramatic impacts such as biodiversity loss. Microbes comprise most of the biodiversity on earth, and the diversity of microbes in the soil is a critical link in maintaining the health of our ecosystems. However, we have little understanding of how alteration of global nutrient supplies is affecting soil microbial biodiversity."

Jizhong Zhou, George Lynn Cross Research Professor and Presidential Professor, Department of Microbiology and Plant Biology in Dodge Family College of Arts and Sciences, University of Oklahoma

Zhou is the director of the Institute for Environmental Genomics and the principal investigator of this five-year project funded by the National Science Foundation. The global collaboration between the United States and China is supported by a total combined equivalent of nearly $2.5 million to advance a global understanding of soil nutrients' impact on microbial diversity to better understand, predict and mitigate the impacts.

Representing the United States in the global collaboration are researchers from OU, led by Zhou and Daliang Ning, a research scientist with IEG, and from the University of Minnesota, led by ecologists and co-principal investigators Elizabeth T. Borer and Eric W. Seabloom. Two organizations in China are contributing to the research coordinated by co-principal investigators Yunfeng Yang at Tsinghua University and Xiangling Fang at Lanzhou University. Additionally, the team is working with more than 200 participants from 26 countries in the Nutrient Network (NutNet), a grassroots research organization composed of more than 130 grassland sites worldwide.

"Using this global research platform, our project will explore different dimensions of diversities of the soil microbes, their evolutionary relationships, their genetic diversity, and what they are doing – their functional diversity," said Zhou.

Zhou and the microbiologists at IEG are specifically leading the microbiome analysis aspect of the study. The research collaborators will send soil samples from around the world to OU, where Zhou's research team will analyze them and look for patterns – general rules that could provide a global baseline and inform future predictions as the global climate continues to change.

"The scientists on this research team will not only determine how these different dimensions of diversity respond to the nutrient change but also why they are changing," Zhou said. "Are microbial communities changing because some microbes can grow better (abiotic filtering), compete or cooperate with other microbes or plants (biotic interactions), or are good or bad at migration (dispersal), or appear by chance (drift)? To do this, we will develop new mathematical models to predict how nutrients change the diversity of soil microbes and their functions in different regions in the future."