Multiple environmental stressors confine the ecological niche of the rotifer Cephalodella acidophila
- 1The planktonic food web in extremely acidic mining lakes is restricted to a few species that are either acidophilic or acidotolerant. Common metazoans inhabiting acidic mining lakes with a pH below 3 include rotifers in the genera Cephalodella and Elosa. 2The life history response of Cephalodella acidophila to three environmental key factors, pH (2, 3.5, 5.0 and 7.0), temperature (10, 17.5 and 25 degrees C) and food concentration (10000, 35000 and 50000algal cells per mL), was investigated in a full factorial design using life-table experiments. 3The effect of each of the three environmental variables investigated on the rotifer life cycle parameters (life span, fecundity and population growth rate) differed. C.acidophila is a stenoecious species with a pH optimum in the range 34 and a comparably high food threshold. Combining the laboratory results with field data, we conclude that C.acidophila is severely growth limited in its natural habitat. However, low pH alone is not harmful as long as temperatures are moderate to warm and1The planktonic food web in extremely acidic mining lakes is restricted to a few species that are either acidophilic or acidotolerant. Common metazoans inhabiting acidic mining lakes with a pH below 3 include rotifers in the genera Cephalodella and Elosa. 2The life history response of Cephalodella acidophila to three environmental key factors, pH (2, 3.5, 5.0 and 7.0), temperature (10, 17.5 and 25 degrees C) and food concentration (10000, 35000 and 50000algal cells per mL), was investigated in a full factorial design using life-table experiments. 3The effect of each of the three environmental variables investigated on the rotifer life cycle parameters (life span, fecundity and population growth rate) differed. C.acidophila is a stenoecious species with a pH optimum in the range 34 and a comparably high food threshold. Combining the laboratory results with field data, we conclude that C.acidophila is severely growth limited in its natural habitat. However, low pH alone is not harmful as long as temperatures are moderate to warm and food is abundant. 4The population of C.acidophila in the field is maintained mainly due to release from competitors and predators.…
