Dynamics of planktonic food webs in three mining lakes across a pH gradient (pH 2–4)

摘要: Acidic mining lakes (ML) in Lusatia (Germany) are characterised by their geogenically determined chemistry. The present study describes the structure, main components and relationships within food webs of three acidic with different pH values (ML 111: 2.6; ML 117: 2.8; Felix: 3.6) order to show typical characteristics. investigation covered period 1995–1997. number species biomass both low, but increase increasing pH. Planktonic most 111 (pH 2.6–2.9) comprise bacteria, Ochromonas spp. Chlamydomonas a few rotifers (E. worallii, C. hoodi). Heliozoans top-predators. In 117 2.8–3) Gymnodinium sp., ciliates, rotifer B. sericus pioneer crustacean Chydorus sphaericus join pelagial community. were not found or Felix 3.4–3.8). had taxa. benthic chain all includes phytobenthic algae as producers, chironomids primary consumers corixids top predators profundal. Corixids predate on small cladocerans inhabiting above 2.8 such Felix. They invade act connecting link between pelagic chains, which isolated lower Occasionally producers abundant lakes. These organisms do depend degree acidity, availability essential ressources. Mass variations up any seasonal variation extremely (0.9 mm3 l−1), while other two patterns found.