Phylogeny of ulotrichalean algae from extreme high-altitude and high-latitude ecosystems

Abstract

Photosynthetic microbes are the dominant primary producers in plant-free high-elevation and high-latitude ecosystems, but we know very little about the terrestrial algae that are found in these systems. Here, we show that terrestrial algae in the Ulotrichales are the dominant 18S algal phylotypes (in terms of relative abundance) in culture-independent studies of geologically similar but geographically distant periglacial sites in the mountains of Central Alaska and the high Himalayas. We further show that these ulotrichalean algae are closely related (using 18S, ITS/5.8S data sets) to several cultured algae from Antarctica and to the dominant ITS algal phylotypes in a recent study of newly deglaciated sediments near the Damma Glacier in Switzerland. Our results further indicate that ulotrichalean algae may play a previously unrecognized role in rock weathering during the earliest stages of primary succession following glacial retreat, but ecological and physiological studies are needed to test this hypothesis.