A freshwater prosobranch, Melanoides tuberculata, in a hydrogen sulphide stream

Submitted by admin on Sun, 20/11/2011 18:55
J. HELLER
S. EHRLICH
(1995)
Volume
35
Part
3
Page from
237

Hydrogen sulphide is poisonous to aerobic organisms and consequently molluscs are rarely found in streams with high concentrations of H2S. In the Arava Desert (Israel) we found a freshwater snail, Melanoides tuberculata, in a stream with a sulphide gradient. The H2S gradient ranged from 7.3 to 0.1 mg/litre, and adult (but not juvenile) M. tuberculata were found to survive in oxygen-depleted water containing hydrogen sulphide concentrations of 34 mg/l. In these micro-habitats M. tuberculata may perhaps breath aerobic oxygen. Juveniles were found further down the gradient and their frequency in the population gradually increased, from 0% at 34 mg/l to 10% at 18 mg/l, and to 56—61% at < 0.1 mg/l. These data suggest either that snails invading the high-sulphide micro-sites do not reproduce, or that they reproduce but the juveniles are unable to survive in the sulphide environment.

Keywords
Hydrogen sulphide
Melanoides tuberculata
freshwater gastropods
environmental factors
juvenile survival
Israel.