5 October
Emma Rosi-Marshall
Assistant Professor, Loyola University and University of Chicago, Departments of Biology and Natural Science
From Ditches to Dammed Rivers: The Effects of Anthropogenic Activities on Riverine Ecosystem Function
Abstract
Human activities, from landuse practices to hydroelectric power generation, have had dramatic effects on riverine ecosystems. In this seminar, I will discuss research that I am currently conducting in 2 very different ecosystems that have been extensively affected by human activities: ditches in the agricultural Midwest and the Colorado River in the Grand Canyon. Agriculturally-dominated ecosystems are the primary landscape feature in the Midwestern US and greater than 90% of headwater streams in this area drain agricultural fields. Given little riparian vegetation, crop residues such as corn foliar detritus and pollen can be blown or washed into streams and represent a novel carbon source. Corn plants have very high rates of pollen production; a single tassel can produce up to 25 million pollen grains (ca. 7.5g) in 5-7 days. Genetically modified corn, specifically Bt Corn, planting is on the rise and we predicted that toxins associated with Bt corn may pose a threat to instream fauna. We measured pollen and foliar detritus input rates to agricultural streams in Benton County, IN to assess the potential exposure to genetically modified crop byproducts. In addition, we are examining, in situ and in laboratory assays, the effects of genetically modified corn on stream invertebrates. Our results, thus far, confirm that corn pollen and foliar detritus enter agricultural streams and potentially pose a threat to invertebrates and that the potential exposure of aquatic organisms to crop residues and toxins associated with genetically modified crops, merits further attention. I will conclude my seminar discussing research that I am currently conducting on the Colorado River, in the Grand Canyon. This research seeks to measure the effects of Glen Canyon Dam and invasive species on food web dynamics and specially how they relate to the endangered native fishes present in the system.
Bio
Emma Rosi-Marshall is an assistant professor at Loyola University Chicago. Emma completed her PhD. in the Institute of Ecology at the University of Georgia in 2002 and a conducted post-doctoral research at Notre Dame, until joining the faculty at Loyola in 2004. She has conducted research at numerous scales of stream ecology from nutrient dynamics to stream periphyton to community dynamics up through food webs to ecosystem function. Emma's current research examines the effects of human activities on stream ecosystem function and she conducts research in agricultural ditches in Indiana, forested headwater streams in Michigan, the Chicago River in Illinois and the Colorado and Snake Rivers. Emma plans to continue to examine the effects of large scale ecological changes, such as urbanization, agriculture, forestry and hydroelectric power generation on various stream ecosystem processes. Her ultimate research goal is to continue to conduct novel ecological research that informs freshwater ecosystem protection.
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