Aspects of the acid tolerance of algae from the Durham area

Abstract

Algal samples were collected from a diverse range of aquatic habitats in the Durham area, with pH values ranging from 3.2 - 9.2, and their acid tolerance in culture was investigated. The pH ranges of occurrence of species in the field were tabulated and their ability to survive in culture at pH 3.3 recorded. The results reveal that some species are restricted to low pH environments among the samples taken, whereas other acid tolerant species can also be found at normal or high pH sites. Acid tolerance was found not to be specific to any particular algal division, the only common division not represented among acid tolerant species being the Cyanophyta. This is in agreement with results of investigations in America. Comparison of species found to be acid tolerant from environments other than minewater drainages, with the flora of an acid minewater drainage at Brandon, suggests that pH is probably the major factor determining the flora of the latter, rather than pH-independent factors characteristic of minewater. Evidence was found showing that tolerance of low pH conditions is a characteristic of particular species to a considerable extent, and samples of these species taken from quite alkaline environments were found to survive at low pH in culture. However, there is also some evidence for the occurrence of adaptation within a species and this may be important. No clear patterns emerged from a floral comparison of the Brandon Acid Streams catchment area and the surrounding countryside. Some experiments on transport of algae by air were carried out, but limited data were collected. It appears that the Acid Stream species are not common among the algae in the air a short distance from the Stream.