A. Locke et Wg. Sprules, EFFECTS OF EXPERIMENTAL ACIDIFICATION ON ZOOPLANKTON POPULATION AND COMMUNITY DYNAMICS, Canadian journal of fisheries and aquatic sciences, 50(6), 1993, pp. 1238-1247
We provide experimental evidence of indirect ecological changes occurr
ing through alterations in both competitive and predatory interactions
within zooplankton communities during acidification. Acidification ex
periments were conducted on zooplankton in 16-m3 enclosures suspended
in a Precambrian Shield lake in central Ontario in order to identify m
echanisms of community change. Changes in abundance, body size, egg ra
tio, and lipid status in zooplankton populations reflected changes in
biotic interactions during acidification to pH between 5.0 and 6.0. Ab
undance of small cladocerans (especially Bosmina longirostris) increas
ed following acidification despite increases in abundance or dominance
of their cyclopoid predators. Increased reproduction of Bosmina, in t
he absence of detectable changes in edible phytoplankton biomass, sugg
ests that this was due to competitive release from larger cladoceran s
pecies that did not survive acidification.