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PINEL-ALLOUL, B., G. MÉTHOT, G. VERREAULT, Y. VIGNEAULT, 1990. Zooplankton species associations in Quebec lakes : variation with abiotic factors, including natural and anthropogenic acidification. Can. J. Fish. Aquat. Sci., 47: 110-121 .
PINEL-ALLOUL, B., G. MÉTHOT, G. VERREAULT, Y. VIGNEAULT, 1990. Phytoplankton in Quebec lakes : variation with lake morphometry, and with natural and anthropogenic acidification. Can. J. Fish. Aquat. Sci., 47: 1047-1057 .
POPE, G., M.-C. TARISSANTS, J.-J. FRENETTE, G. VERREAULT, J.-L. DESGRANGES, 1989. Effets des facteurs biotiques et abiotiques sur la structure et les relations trophiques des communautés planctoniques et benthiques : revue des hypothèses. Rapp. tech. can. sci. halieut. aquat., 1687, 59 p .
Trophic models describing the effects of predation and competition on zooplankton and benthic community structures are reviewed. Older models emphasized the influence of biotic factors to explain community composition whereas more recent models concede that physical-chemical factors can modify community structure. Acidification, biogeographic isolation and winter anoxia are three environmental factors that reduce the species diversity and total abundance of fish and the resulting predation pressure on lower trophic levels in Quebec lakes. European investigators have hypothesized that many of the changes in plankton and benthic communities resulting from acidification would naturally occur in lakes with altered fish predation. The effects of acidification on lower trophic levels in North American lakes are reviewed and it is concluded that the sequence of changes in the lower trophic levels are difficult to explain using current trophic models. In particular, trophic models predict the dominance of large herbivores in the zooplankton of lakes with low fish predation, whereas in North America, the zooplankton of acidified lakes is usually dominated by small herbivores. Lynch's model predicts the latter response if acidification leads to a reduction of phytoplankton productivity. However, survey results are equivocal as to the effect of acidification on productivity.
AHERN, A., S. CANTIN, G. VERREAULT, 1987. Étude de l'activité bactérienne et fongique de quatre rivières à saumons de la Côte-Nord du Saint-Laurent, en relation avec des conditions physico-chimiques acides. Rapp. tech. can. sci. halieut. aquat., 1565, 30 p .
Respiratory activity of bacteria and fungi in running waters has been analyzed in order to evaluate the pertinence of this biological information as an indication of acid rain effects on salmon rivers of the Quebec North-Shore. Homogenized leaf (Alnus sp) substrates were incubated in situ during 16-20 days and oxygen consumption was measured in september 1984 and june 1985. The Laval (pH spring and annual mean > 6,5), Trinité (pH spring < 5,5 and annual mean 6,0) and Matamec (pH spring < 5,0 and annual mean < 6,0) rivers were selected. Results showed : 1) that a significant difference in respiratory activity was registered in the Matamec river in september, showing values 30-50 % lower than that registered at the same time in Trinité and Laval rivers, which were not significantly different; 2) that a significant difference in June was registered in respiratory activity of the 3 rivers, showing gradual difference (Matamec < Trinité < Laval) similar to the acidity gradient scale pre-established on rivers of the Quebec North-Shore; and 3) that a highly significant spatial dependence was observed between respiratory activity and pH + temperature, the pH contributing to more than 99 % of the total variability in june and 63% in september.
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