NSERC grants at Laurentian University Subventions du CRSNG `a l ...

29John Gunn with/avec William Keller, Norman Yan& Charles RamcharanIn partnership with/En collaboration avec Falconbridge Ltd& International Nickel Company LtdBarriers to biological recovery in historically disturbedSudbury Lakes: Lingering toxicity or ecological bottlenecks?A grant of $378,867 for four years.Une subvention de 378 867 $ pour quatre ans.Collaborative Research and Development Grant –Subventions de recherche et développement coopérativeIn recent decades, billions of dollars have been spent to prevent and reversethe damages caused by acid deposition in thousands of lakes and riversaround the world. This massive environmental problem reached its peak inthe late 1970s and 1980s, and since then there has been widespread evidenceof water quality improvements following regulated emission reductions. However,biological recovery in damaged systems has lagged far behind the chemicalimprovements and there are many competing hypotheses to accountfor the delays. The study of the factors (physical, geochemical, or biotic)that control the recovery or resilience of disturbed ecosystems is thereforeof great interest to both applied and theoretical ecologists, especially at thebroad landscape levels at which the acidification impacts occurred. The areaaround the metal smelters in Sudbury, Ontario, represents an especially importantstudy site in this regard because of the scale and duration of thedamage (> 100M tons of S0 2 emitted, an estimated 7000 damaged lakes)and the wealth of existing synoptic and long-term monitoring data for thisarea. Our study addresses two hypotheses. The first, which applies particularlyto the many mining regions of the world, is that atmospheric or liquideffluent inputs of persistent and non-degradable contaminants, such as metals(Cu, Ni, etc.) prevent the recolonization of sensitive organisms and alsoaffect the functional processes (such as productivity or nutrient cycling) ofacid/metal damaged systems in ways that acidifying compounds (H+, S0 4 ,NOx) alone do not. The second hypothesis, critical to the field of disturbanceecology, is that food web-alterations create significant “biological resistance”