Assistant Professor of Microbiology & Molecular Genetics

Ph.D. Dartmouth College, 2004

W. K. Kellogg Biological Station 
Michigan State University
Hickory Corners, MI 49060
Phone: (269) 671-2340
Fax: (269) 671-2104
Email: lennonja@msu.edu

Lennon Lab Website

Research Interests

My research is motivated by the effects of resource variability on ecosystem structure and function. Changes in the source and supply of resources have profound effects on important ecological attributes including nutrient cycling, productivity, and the way in which species interact with one another. This overarching theme has inspired most of my research efforts to date, including questions related to the spread of invasive species, cultural eutrophication, microbial controls on carbon flow, and most recently, the influence of nutrient supply on the coevolution of marine viruses and their bacterial hosts. I address these broad topics with simulation modeling, laboratory experiments, mesocosm studies, and comparative surveys.

Energetic importance of terrestrial carbon in aquatic ecosystems - Aquatic ecosystems receive large quantities of terrestrial-derived carbon in the form of dissolved organic matter (DOM).  Although historically perceived as a low-quality resource, DOM supply influences whether aquatic ecosystems function as sources or sinks of atmospheric CO₂.  I am interested in how DOM supply influences carbon flow in plankton food webs and rates of ecosystem processes.   

Function and diversity of bacterial communities - Bacteria are highly diverse and directly involved in most ecosystem processes.  I am interested in understanding how variation in the source, supply, and timing of resources (i.e., DOM and inorganic nutrients) influences the composition, phylogenetic identity, and metabolic activity of aquatic and terrestrial microbial communities.  

Ecological and evolutionary roles of viruses in aquatic ecosystems- Viruses are the most abundant biological entities on the planet, yet we are just beginning to appreciate the ecological and evolutionary roles that they play in natural ecosystems.  I am interested in how nutrient supply affects the coevolutionary dynamics between viruses and the marine cyanobacterium,  Synechococcus.  Conversely, I am also interested in how the evolution of viral-resistance influences nutrient turnover rates.

Local and regional controls on biological invasions- The spread of exotic species poses one of the largest threats to biodiversity.  I am interested in understanding how local controls, such as food web structure and nutrient supply, confer resistance to invasion by exotic species.  I am also interested in how regional factors, like dispersal limitation, influence the distribution of exotic species. 

Lennon JT and Cottingham KL (In Press) Microbial productivity in variable resource environments.  Ecology.

Lennon JT(2007) Diversity and metabolism of marine bacteria cultivated on dissolved DNA.  Applied and Environmental Microbiology. 73: 2799-2805.

Lennon JT, Faiia AM, Feng X, Cottingham KL (2006) Relative importance of CO₂ recycling and CH₄ pathways in lake food webs along a terrestrial carbon gradient.  Limnology and Oceanography.  51: 1602-1613.

Lennon JT, Pfaff LE. (2005) The source and supply of terrestrial carbon affects aquatic microbial metabolism. Aquatic Microbial Ecology. 39:107-119.

Cottingham KL, Lennon JT, Brown BL (2005) Knowing when to draw the line: designing more informative ecological experiments. Frontiers in Ecology and the Environment. 3: 145-152.

Lennon JT (2004) Experimental evidence that terrestrial carbon subsidies increase CO₂ flux from lake ecosystems. Oecologia 138: 584-591.

Lennon JT, Smith VH, Dzialowski AR (2003) Invasibility of plankton food webs along a trophic state gradient. Oikos 102: 191-203.

Cottingham KL, Brown BL, Lennon JT (2001) Biodiversity may regulate the temporal variability of ecological systems. Ecology Letters 4: 72-85.