For the most recent list of publications see:

Selected publications: 


Targeting Bacteria and Methanogens To Understand the Role of Residual Slurry as an Inoculant in Stored Liquid Dairy Manure

Authors: Jemaneh Habtewold, Robert Gordon, Vera Sokolov, Andrew VanderZaag, Claudia Wagner-Riddle, Kari Dunfield

Publication date: 2018/1/26;  Applied and environmental microbiology

Microbial communities in residual slurry left after removal of stored liquid dairy manure have been presumed to increase methane emission during new storage, but these microbes have not been studied. While actual manure storage tanks are filled gradually, pilot-and farm-scale studies on methane emissions from such systems often use a batch approach. In this study, six pilot-scale outdoor storage tanks with (10% and 20%) and without residual slurry were filled (gradually-or in batch) with fresh dairy manure, and methane and methanogenic and bacterial communities were studied during 120 days of storage. Regardless of filling type, increased residual slurry levels resulted in higher abundance of methanogens and bacteria after 65 d of storage. However, stronger correlation between methanogen abundance and methane flux was observed in gradually-filled tanks. Despite some variations in the diversity of …


Spatial variability of microbial communities in a fractured sedimentary rock matrix impacted by a mixed organics plume

Authors: Gláucia da P Lima, Jessica R Meyer, Kamini Khosla, Kari E Dunfield, Beth L Parker

Publication date: 2018/11/1; Journal of contaminant hydrology

Dissolved phase contaminants, transported by diffusion into the low permeability matrix of fractured sedimentary rock, pose a challenge to groundwater cleanup efforts because this stored mass may persist even when the upgradient source zone is removed. In this context, if contaminant biodegradation takes place within the low permeability matrix, plume persistence may be substantially reduced. Therefore, it is important to characterize microbial communities within the low permeability, rock matrix pores, instead of only from groundwater samples, which represent biomass from fast flowing fractures. This research relies on depth-discrete data from both core and groundwater samples collected from two locations representing a mid-plume and plume front condition within an aged, mixed organic contaminant plume in a sedimentary rock aquifer. Results from multiple analyte measurements on rock and groundwater …

When too much isn’t enough: Does current food production meet global nutritional needs?

Authors: Krishna Bahadur KC, Goretty M Dias, Anastasia Veeramani, Clarence J Swanton, David Fraser, Dirk Steinke, Elizabeth Lee, Hannah Wittman, Jeffrey M Farber, Kari Dunfield, Kevin McCann, Madhur Anand, Malcolm Campbell, Neil Rooney, Nigel E Raine, Rene Van Acker, Robert Hanner, Samantha Pascoal, Shayan Sharif, Tim G Benton, Evan DG Fraser

Publication date, 2018/10/23; PloS one

Sustainably feeding the next generation is often described as one of the most pressing “grand challenges” facing the 21st century. Generally, scholars propose addressing this problem by increasing agricultural production, investing in technology to boost yields, changing diets, or reducing food waste. In this paper, we explore whether global food production is nutritionally balanced by comparing the diet that nutritionists recommend versus global agricultural production statistics. Results show that the global agricultural system currently overproduces grains, fats, and sugars while production of fruits and vegetables and protein is not sufficient to meet the nutritional needs of the current population. Correcting this imbalance could reduce the amount of arable land used by agriculture by 51 million ha globally but would increase total land used for agriculture by 407 million ha and increase greenhouse gas emissions. For a growing population, our calculations suggest that the only way to eat a nutritionally balanced diet, save land and reduce greenhouse gas emissions is to consume and produce more fruits and vegetables as well as transition to diets higher in plant-based protein. Such a move will help protect habitats and help meet the Sustainable Development Goals.