THE EFFECT OF LIME ON THE ZOOPLANKTON POPULATION OF SANDY LAKE

liming of Sa nd y lake, Nova Scotia, during July and August of 1961 produced an abrupt and transient increase in the pH of the lake and concurrent changes in the zooplankton community. Immediately following liming, the dadoceran Bosmina Iong;ro5tris could not be recovered from the lake but returned the following year after pH levels had fallen to pre·liming levels. The acidophilic rotifer Keratella taurocephala was also less numerous subsequent to liming. Other species, particu-larly rotifer species, were either more numerous o r were collected for the fi rst time in the two years immediately following the liming. l e chaulage du lac Sandy en Nouvelle Ecosse pendant juillet et aoOt de 1961 a provoque une augmentation brusque et tra nsitoire dans Ie pH du lac et en meme temps des changements dans les communautes de zooplanktons. Immediatement apres Ie chaulage, Ie cladoceran Bosmina longiros-uis a disparu du lac pour reappaitre I'annee suivante apres Que Ie niveau de pH soit retombe au niveau observe avant lechaulage. la population des rotiferesacidophiles Kera!ella raurocephala a eti! reduile apres Ie chaulage. D'aulresespeces, el en particulier les especes de rotiferes,onl etesoit plus nombreuses, soil collectionees pour la premiere fois dans les deux ans immediatement suivant Ie chaulage du lac