Bipolar dispersal of red-snow algae

Takahiro Segawa,Hiroshi Mori,Nozomu Takeuchi,Ayumi Akiyoshi,Shin Sugiyama,Ryo Matsuzaki,Takahiro Yonezawa,Francisco Navarro

doi:10.1038/s41467-018-05521-w

Abstract

Red-snow algae are red-pigmented unicellular algae that appear seasonally on the surface of thawing snow worldwide. Here, we analyse the distribution patterns of snow algae sampled from glaciers and snow patches in the Arctic and Antarctica based on nuclear ITS2 sequences, which evolve rapidly. The number of phylotypes is limited in both polar regions, and most are specific to either the Arctic or Antarctica. However, the bipolar phylotypes account for the largest share (37.3%) of all sequences, suggesting that red-algal blooms in polar regions may comprise mainly cosmopolitan phylotypes but also include endemic organisms, which are distributed either in the Arctic or Antarctica.

Highlights

Red-snow algae are red-pigmented unicellular algae that appear seasonally on the surface of thawing snow worldwide
64,047 unique sequences for algal internal transcribed spacer 2 (ITS2) were found in all the red-snow samples, and 348 operational taxonomic units (OTUs) were defined with ≥98% nucleotide sequence identity
In the ITS2 sequence, only 38 of 348 OTUs were >95% similar to the culturable strains in the National Center for Biotechnology Information (NCBI)-nt database, indicating that the majority of red-snow algae strains for which an OTU was identified have yet to be successfully cultured

Summary

Introduction

Red-snow algae are red-pigmented unicellular algae that appear seasonally on the surface of thawing snow worldwide. 1234567890():,; Red snows are a worldwide phenomenon during the melt season and are caused by blooms of red-pigmented green algae (Chlorophyceae) in thawing snow They have been recorded in the daily logs of polar and alpine explorers such as Captain John Ross and Charles Darwin[1,2] (Fig. 1). Red-snow algae collected from different regions of the Arctic were reported to be cosmopolitan based on 18S rRNA gene analysis[11]. This gene has frequently been used for establishing algal taxonomy at the species level[4,12]. We show that some red-snow algal phylotypes have a bipolar distribution, whereas others are present in only limited areas

Methods

Results

Conclusion