The Effects of Low pH and Aluminum on Breeding Success in the Frog Rana temporaria

Abstract

The effects of low pH on fertilization and embryonic development in Rana temporaria (L.) were studied in the laboratory and field. In the field, fertilization success was reduced principally by high concentrations of inorganic monomeric aluminum, while embryonic mortality was caused mainly by low water temperatures. Most dead eggs were at the mid to late cleavage or early gastrula stage. In the laboratory, embryonic survival decreased with increasing inorganic monomeric aluminum concentration at pH 4.5. High concentrations of inorganic monomeric aluminum also increased the number of embryos which died in the early stages of development, and increased the proportion of embryos which remained constricted within the perivitelline membrane and failed to hatch