The interaction of soil and lake microflora at Signy Island.

Abstract

Lakes on Signy are small and, during the summer ice-free period, receive a substantial influx of run-off from the surrounding catchment, greatly in excess of their total volume. Within the various habitats comprising each lake's catchment area, large populations of bacteria, yeasts and fungi exist. Transport of terrestrial micro-flora to the lakes in run-off water is demonstrated by the appearance of Chromobacterium and yeasts in lake surface waters at around the same time as their numbers increase in certain terrestrial habitats. However, close examination reveals substantial differences between lake and terrestrial populations, the most obvious being the virtual absence of gram-positive bacteria from lake samples whilst comprising 20% of terrestrial populations. The composition of lake populations differs between lakes, and between lakes and their catchment populations, explicable in terms of catchment composition and nutrient availability.-from Authors