Frozen Zoo: a collection of permafrost samples containing viable protists and their viruses

Stas Malavin,Lyubov Shmakova,Jean-Michel Claverie,Elizaveta Rivkina

doi:10.3897/bdj.8.e51586

Abstract

BackgroundPermafrost, frozen ground cemented with ice, occupies about a quarter of the Earth’s hard surface and reaches up to 1000 metres depth. Due to constant subzero temperatures, permafrost represents a unique record of past epochs, whenever it comes to accumulated methane, oxygen isotope ratio or stored mummies of animals. Permafrost is also a unique environment where cryptobiotic stages of different microorganisms are trapped and stored alive for up to hundreds of thousands of years. Several protist strains and two giant protist viruses isolated from permafrost cores have been already described.New informationIn this paper, we describe a collection of 35 amoeboid protist strains isolated from the samples of Holocene and Pleistocene permanently frozen sediments. These samples are stored at −18°C in the Soil Cryology Lab, Pushchino, Russia and may be used for further studies and isolation attempts. The collection strains are maintained in liquid media and may be available upon request. The paper also presents a dataset which consists of a table describing the samples and their properties (termed "Sampling events") and a table describing the isolated strains (termed "Occurrences"). The dataset is publicly available through the GBIF portal.

Highlights

Permafrost, or perennially frozen ground, is the ground that remains below zero degrees Celsius for two or more consecutive years (Goudie 2004, p. 777)
We describe a collection of 35 amoeboid protist strains isolated from the samples of Holocene and Pleistocene permanently frozen sediments
Subzero temperatures down to −50°C are not incompatible with certain metabolic reactions in bacteria (Rivkina et al 2000, Bakermans et al 2003, Price and Sowers 2004, Johnson et al 2007, Rohde et al 2008), including even DNA replication (Tuorto et al 2014), the main factor limiting the metabolism in permafrost deposits is the lack of sufficient amount of liquid water (Rivkina et al 2000)

Summary

Background

Permafrost, frozen ground cemented with ice, occupies about a quarter of the Earth’s hard surface and reaches up to 1000 metres depth. Several protist strains and two giant protist viruses isolated from permafrost cores have been already described. We describe a collection of 35 amoeboid protist strains isolated from the samples of Holocene and Pleistocene permanently frozen sediments. These samples are stored at −18°C in the Soil Cryology Lab, Pushchino, Russia and may be used for further studies and isolation attempts. The collection strains are maintained in liquid media and may be available upon request. The paper presents a dataset which consists of a table describing the samples and their properties (termed "Sampling events") and a table describing the isolated strains (termed "Occurrences").

Introduction

Findings

Sampling methods