Dr. O’Brien studies ecosystem ecology in freshwater rivers, streams and wetlands. The goal of his research is to understanding how human activities alter the basic functions an ecosystem, such as ability to metabolize carbon, cycle nutrients and support a diverse food web. In particular, his research program examines the cycling of nitrogen and phosphorous in freshwater ecosystems, and also examines how changes in ecosystem productivity results in bottom up effects that alter food web structure. The ultimate goal of his research is to apply this knowledge to help restore degraded ecosystems.
The Ecosystem Ecology Lab at Canisius College supports a diverse array of undergraduate-student centered research projects. Students in Dr. O’Brien lab conduct projects looking at the effects of nutrients and emerging contaminants on river biofilms (i.e., collections of algae and bacteria that are essential for proper ecosystem function). Students in his lab also work on projects investigating how invasive species and changing land-uses alter the basic energy flows through river food webs. Students often have the opportunity to travel and present the findings of their projects to other scientists at regional meetings, such as the Midwest Ecology and Evolution Conference, or national meetings such the Society for Freshwater Science.
Dr. O’Brien teaches classes in the Biology, Environmental Science and All College Honors programs. His upper-level classes include Freshwater Biology; Wetlands; Environmental and Pathogenic Microbiology; Hydrology; and Water and Society. He particularly enjoys teaching the freshman Introductory Biology sequence each year.
O’Brien, J.M., S.K. Hamilton, L. Podzikowski and N. Ostrom (2012) The fate of assimilated N in stream biofilms: an in-situ benthic chamber study. Freshwater Biology 57: 1113–1125.
Burrell, T.K., J.M. O’Brien, S.E.Graham, J.S. Harding and A.R. McIntosh (2014) Riparian shading mitigates the eutrophication of streams by agricultural land use. Freshwater Sciences 33: 74-84.
O’Brien, J.M., J.L. Lessard, D. Plew, S.E Graham and A.R. McIntosh (2014) Aquatic macrophytes alter metabolism and nutrient cycling in lowland agricultural streams. Ecosystems 17: 405-417.
Kinsman-Costello, L.E., J.M. O’Brien, and S.K. Hamilton (2014) Re-flooding a historically drained wetland leads to rapid sediment P release. Ecosystems 17: 641-656
Graham, S.E., J.M. O’Brien, T.K. Burrell and A.R. McIntosh (2015) Aquatic macrophytes alter productivity-richness relationships in eutrophic stream food webs. Ecospheres 6:87