Sublethal Effects of Nitrite on Eastern Tiger Salamander (<Emphasis Type="Italic">Ambystoma tigrinum tigrinum</Emphasis>) and Wood Frog (<Emphasis Type="Italic">Rana sylvatica</Emphasis>) Embryos and Larvae: Implications for Field Populations

Ephemeral pools, which can have high animal biomass and low dissolved oxygen, may be prone to nitrite accumulation. As such, it is important to understand how exposure to nitrite might affect development and growth of amphibians that breed in these ephemeral pools. Wood frog (Rana sylvatica) and eastern tiger salamander (Ambystoma tigrinum tigrinum) embryos and tadpoles and young larvae were exposed to elevated concentrations of nitrite derived from sodium nitrite: 0, 0.3, 0.6, 1.2, 2.1, 4.6, and 6.1 mg l⁻¹ NO₂–N. Increasing nitrite exposure slowed embryonic and larval development in both the eastern tiger salamander and the wood frog, reduced growth in tiger salamander embryos and larvae, and delayed metamorphosis in the wood frog. At concentrations less than 2 mg l⁻¹ NO₂–N nitrite delayed hatching, and at concentrations above 2 mg l⁻¹ time to hatching decreased causing more individuals to hatch at less developed stages. Nitrite also increased asynchrony in tiger salamander hatching. The sublethal effects of nitrite on amphibian development, growth and hatching could have serious repercussions on amphibian fitness in ephemeral environments. Potential increases in mortality on field populations caused by sublethal effects of nitrite are discussed.