Biodiversity and Abundance of Cultured Microfungi from the Permanently Ice-Covered Lake Fryxell, Antarctica.

Laurie Connell,Regina Redman,Hubert Staudigel,Benjamin Segee,Russell Rodriguez

doi:10.3390/life8030037

Abstract

In this work, we explore the biodiversity of culturable microfungi from the water column of a permanently ice-covered lake in Taylor Valley, Antarctica from austral field seasons in 2003, 2008 and 2010, as well as from glacial stream input (2010). The results revealed that there was a sharp decline in total culturable fungal abundance between 9 and 11 m lake depth with a concurrent shift in diversity. A total of 29 species were identified from all three water sources with near even distribution between Ascomycota and Basidomycota (15 and 14 respectively). The most abundant taxa isolated from Lake Fryxell in 2008 were Glaciozyma watsonii (59%) followed by Penicillium spp. (10%), both of which were restricted to 9 m and above. Although seven species were found below the chemocline of 11 m in 2008, their abundance comprised only 10% of the total culturable fungi. The taxa of isolates collected from glacial source input streams had little overlap with those found in Lake Fryxell. The results highlight the spatial discontinuities of fungal populations that can occur within connected oligotrophic aquatic habitats.

Highlights

Lake Fryxell in Taylor Valley, geographically part of the McMurdo Dry Valleys region of Antarctica is a permanently ice-covered lake with an average of 6 m of ice. This area is the focus of decades of research and more recently tourism, may be vulnerable to human impacts. This lake is primarily fed by melt water from the Canada and Commonwealth Glaciers (Figure 1—photo of area with glaciers feeding lake)
An active microbial loop exists in Lake Fryxell as described by Bowman and coworkers [2] is based on decades of microbial research on prokaryotes [3,4,5,6,7,8,9,10] and eukaryotes [7,11,12,13,14,15,16,17,18]
One of the earliest studies of fungi associated with Lake Fryxell [20] described culturable yeasts in the algal mats that form on the lake shore but, sampling did not include either lake water or sediment

Summary

Introduction

Lake Fryxell in Taylor Valley, geographically part of the McMurdo Dry Valleys region of Antarctica is a permanently ice-covered lake with an average of 6 m of ice. An active microbial loop exists in Lake Fryxell as described by Bowman and coworkers [2] is based on decades of microbial research on prokaryotes [3,4,5,6,7,8,9,10] and eukaryotes [7,11,12,13,14,15,16,17,18]. Fryxell water at several depths below a permanent ice cover as well as from streams at the terminus of Fryxell water at several depths below a permanent ice cover as well as from streams at the terminus of the two major glaciers feeding Lake Fryxell during austral field seasons 2003, 2008 and 2010.

Materials andand

Sample Collection and Processing

Neighbor

Fungal Distribution

Discussion