From: Madhur Anand
To: Sigma Xi Distinguished Lecture Series
Subject: January 28, 2010-Sigma Xi Distinguished Lecture (University of Toronto)
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SIGMA XI UNIVERSITY OF TORONTO CHAPTER DISTINGUISHED LECTURE SERIES
http://www.sigmaxi.utoronto.ca/events
The Emerging Threat of Environmental Ca Decline
Norman Yan Professor, Department of Biology, York University
Thursday, January 28, 2010, 4:30pm
Ramsay Wright Zoological Laboratories
25 Harbord Street, Lecture Room 432 University of Toronto
Location map: http://www.sigmaxi.utoronto.ca/events/location.html
Abstract: There is a growing realization that recent, widespread decreases
in calcium (Ca) concentrations are posing a threat to life in softwater
lakes in central and eastern Canada. Ca concentrations in lakes fall if the
exchangeable Ca pools in watershed soils are depleted; and such depletion
may occur if additions of Ca to the soil from weathering and atmospheric
input consistently fall below losses attributable to acid deposition and
timber harvesting followed by forest re-growth. In this review, I will: 1)
briefly review the causes of Ca decline in Canadian softwater lakes; 2)
summarize Ca concentration thresholds that are problematic for a key group
of freshwater biota, the Crustacea; 3) review the evidence that Ca decline
is now widespread; and 4) that levels have now broached, or are approaching
damaging thresholds in many lakes. There is an urgent need for Canadian
ecologists to improve understanding of the effects of Ca decline on aquatic
biota, and to understand the interactive effects of Ca decline with other
environmental stressors, particular acidity and climate warming. Currently,
those charged with the management of North America lakes have not considered
the effects of low Ca levels on aquatic life, separate from effects of
acdiity. Given the threat of Ca decline, his situation must change.
All students, faculty, and the general public are welcome.
--
Madhur Anand
Associate Professor & Canada Research Chair
Global Ecological Change (GEC) Laboratory
School of Environmental Sciences
University of Guelph
Guelph, Ontario
N1G 2W1
519-824-4120 x56254
http://www.uoguelph.ca/~manand
President,
Sigma Xi, The Scientific Research Society
University of Toronto Chapter
http://www.sigmaxi.utoronto.ca/index.html
co-Editor, Regreen: New Canadian Ecological Poetry
http://www.yourscrivenerpress.com/default.asp?id=2055
Café Scientifique 2009-10
http://www.uoguelph.ca/cafescientifique
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