Nutrients and Pollutants in Aquatic Systems - Making Sense of Complex Controls at the Landscape Scale
Presented by Jesse Becker
Wednesday, July 1, 2015
My research uses a landscape perspective to answer questions about the effects of human alteration to and interaction with aquatic ecosystems. Understanding large-scale processes can inform ecosystem managers and better inform ecologists so that our expectations of management and restoration activities are more aligned with ecologically reasonable outcomes. I will present the findings from two large watershed studies on how landscape properties influence aquatic nutrients and pollution.
I will also present preliminary findings from a student centered national survey of pharmaceuticals and personal care products in rivers and streams. Humans have influenced nearly every ecosystem on earth, and as population grows the function and services on which we rely will have to be provided by ecosystems that are more substantially altered. A better understanding of large-scale processes is needed in order to meet long-term goals of environmental sustainability.
Reem-Kayden Center Laszlo Z. Bito '60 Auditorium Sponsored by: Dean of the College.
Ghosts of Photosynthesis Past and the Green Trojan Horse: Effects of Atmospheric Change and Infection on Competition in Plant Communities
A lecture by Emily Pollina, University of Virginia, College at Wise
Thursday, July 16, 2015
Changes to the global atmosphere, including increasing levels of carbon dioxide and tropospheric ozone, can significantly alter plant physiology, competition, and community composition. However, much less is known about the effects of these atmospheric changes on viral plant disease, despite the profound effects such diseases can have on their hosts and communities. I used open top chambers in the field to examine the effects of rising carbon dioxide and ozone on the probability of disease establishment and proportion of plants infected by barley yellow dwarf virus (BYDV), an economically and environmentally important pathogen of plants in the grass tribe. I examined the effects of both gases on within-host viral fitness, viral spread and host competition in monocultures and mixtures of two grasses: the epidemiologically important host Avena fatua and the poor viral host Setaria lutescens. Elevated levels of carbon dioxide alone increased the probability of disease establishment in Avena, but elevated levels of both atmospheric gases reduced the probability of disease establishment. In mixtures of Avena and Setaria, within-host viral fitness and transmission rates in both Avena and Setaria were enhanced. In addition, when Avena and Setaria were grown in competition, carbon dioxide reduced the benefits to Avena of growing in mixtures across infection treatments. Although presence in mixtures significantly suppressed growth in Setaria, CO2 increased reproductive output in infected plants. These results suggest an important role for infection in grassland communities under changing global atmospheres.
RKC 115 Sponsored by: Dean of the College; Division of Science, Mathematics, and Computing.