Studies on Central African Pans III

Abstract

Measurement have been recorded of alkalinity, pH, and diurnal temperature variation in twelve shallow ephemeral rain pools on aeolian Kalahari sand in Central Africa. These twelve pools were representative of many throughout the region and covered a wide range of volumes. All the pools, however, were subject to rapid temperature fluctuations on hot sunny days, from temperatures in water and mud of 20°C–25°C in the morning to 35°C–38°C (water) and 30°C–35°C (mud) in the afternoon. Where vegetation was present in larger pools and where ungulate faeces were abundant, the pools developed organic sediments which were analysed during the dry season. Organic (faecal) pollution was common in pools lying on salt lick areas frequented by game animals, and was therefore most marked in alkaline pools.