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GLIN==> Two Upcoming Seminar Notices



 
Wednesday,  May 02, 2001

GLERL-CILER Joint Seminar Series
TITLE: "A SPATIAL TRANSECT MODEL FOR ESTIMATING ECOLOGICAL RISKS IN THE PATUXENT RIVER"

SPEAKER: Dr. Steve Bartell, The Cadmus Group, Inc., Oak Ridge, TN
TIME: 10:30 a.m.
WHERE: GLERL Main Conference Room

CONTACT: Dr. David Reid, NOAA/GLERL, 734-741-2019

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Thursday, May 24, 2001
 NOTE DATE
 & TIME CHANGE
 
GLERL-CILER Joint Seminar Series
TITLE: "RELATIVE IMPACTS OF CLIMATE, AGRICULTURE AND URBANIZATION ON WATER QUALITY AND SOCIETY IN CENTRAL NORTH AMERICA"
 
SPEAKER: Dr. Peter R. Leavitt, Department of Biology, University of Regina, Saskatchewan, Canada
TIME: 2:30 p.m.
WHERE: GLERL Main Conference Room
ABSTRACT: Changes in climate, land-use practices and human population distribution are among the most severe stressors of aquatic ecosystems, yet little is known of their relative importance in regulating water quality. In this talk, I will present new analyses from central North America which illustrate two contrasting scenarios; one in which human impacts overwhelm the influence of climate change, and one in which climate change may overwhelm  human society.

 In the first case, analysis of fossils from lake sediments (pigments, stable isotopes, diatoms, invertebrates) show that while regional lakes are naturally productive, sewage from cities degrades water quality, leading to a 500% increase in primary production since 1900. Comparison among lakes along a  landscape gradient demonstrates that while point-source sewage degraded water quality in some lakes, natural aquatic ecosystems have substantial
capacity to completely remove excess nitrogen arising from human activities. In contrast, impacts of agricultural practices are limited to headwater (upstream) lakes, whereas climate is consistently unimportant relative to human activities.

In the second example, I use paleoclimate records from the past 2000 years to quantify the risks of future droughts. Analyses demonstrate that economically- and socially-severe droughts are a natural component of the North American environment, and that the climate of the 20th century has  been unusually benign. Our forecasts predict that a drought equivalent to those of the 1930s, when 25% of human population was forced to relocate, have over a 50% probability of recurring within the next 30 years. Further, we find these droughts are among the mildest on record, suggesting that future, natural climatic variability may be sufficient to disrupt human society or economy in this region. Further information on this project is available at      http://www.uregina.ca/drought

CONTACT: Dr. David Reid, NOAA/GLERL, 734-741-2019
 
 

**********
Renda S. Williams
Executive Secretary to the Director
Phone: 734-741-2245
Fax: 734-741-2003
E-Mail: williams@glerl.noaa.gov