Relationships between zooplankton community structure and phytoplankton in two lime‐treated eutrophic hardwater lakes

Abstract

1. North Halfmoon Lake and Lofty Lake (Alberta, Canada) were chosen for whole‐lake liming experiments as a new restoration technology to enhance calcite precipitation and reduce eutrophication. During a 3‐year study (1991–93) the relationships between zooplankton and phytoplankton were assessed, together with the effects of lime additions. 2. Zooplankton communities were numerically dominated by rotifers, while the major contribution to biomass was due to large filter‐feeding Daphnia during the first half of the summer season. In Lofty Lake, cladocerans made up to 93% of biomass, whereas in North Halfmoon Lake both cladocerans and calanoids were strongly represented. 3. Total zooplankton and cladoceran biomasses were inversely correlated with chlorophyll a (chl a). The same relationship was found between large Daphnia (≥ 1 mm) and chl a. These relationships suggest that the decline in Daphnia may have been caused by an increase in cyanobacteria biomass during bloom events. 4. There were minor changes in rotifer populations after liming; however, these changes have been caused by natural year‐to‐year variation rather than liming. In general, cladocerans showed an increase in body size and population biomass when pre and post‐treatment data were compared by means of ANCOVA. Statistical analysis showed that there were more cladocerans per unit of chl a after liming; however, further research is needed to relate these patterns unambiguously to the application of lime as a restoration technology.

Planktonic rotifers of a saline-lowland river : the Salado River (Argentina)

“…Some perennial species (such as B. caudatus, B. calyciflorus, K. tropica, and F longiseta) are typical of eutrophic environments (Ghadouani et al 1998) and are indicative of the trophic state of the Salado River.…”

“…Rotifers are an important component of the plankton in lowland rivers in terms of both specific richness and density (Walker 1992, Admiraal et al 1994, Pourriot et al 1997). This predominance is the result of their rapid reproductive capacity during optimal conditions, their short generation time and their ability to develop large populations in eutrophic environments (Ghadouani et al 1998, Gosselain et al 1998, Lair et al 1998. (2) To date, the study of planktonic rotifers in the rivers and streams of Buenos Aires province is limited to the contributions of Kuczynski (1984), Modenutti & Claps (1988) and Modenutti (1991Modenutti ( , 1998.…”

Eutrophication conditions and ecological status in typical bays of Lake Taihu in China

“…Zooplankton were anaesthetized in situ with carbonated water and preserved for analysis in a 4% buffered sugar formaldehyde solution. Zooplankton samples were analyzed with a stereomicroscope, according to Ghadouani et al (1998).…”

Food spectrum of the omnivorous rotifer Asplanchna priodonta in two large northeastern European lakes of different trophy

“…Cyanobacteria may be avoided by herbivorous zooplankton for several reasons, including that they are nutritionally deficient food for zooplankton because they may be toxic through the production of microcystins (Ghadouani et al 1998, Nandini & Rao 1998. Zooplankton feeding and growth rates have been shown to decrease when exposed to microcystins.…”