Independent Shifts of Abundant and Rare Bacterial Populations across East Antarctica Glacial Foreland.

Yuansheng Li,Yu Zhang,Bo Sun,Wenkai Yan,Xiang Xiao,Hongmei Ma,Guitao Shi

doi:10.3389/fmicb.2017.01534

Yuansheng Li, Yu Zhang + Show 5 more

Open Access

https://doi.org/10.3389/fmicb.2017.01534

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Abstract

Glacial forelands are extremely sensitive to temperature changes and are therefore appropriate places to explore the development of microbial communities in response to climate-driven deglaciation. In this study, we investigated the bacterial communities that developed at the initial stage of deglaciation using space-for-time substitution in the foreland of an ice sheet in Larsemann Hills. A series of soil samples across the glacial foreland were deeply sequenced with 16S rRNA gene amplicon sequencing to determine the bacterial community, including both abundant bacteria, which contribute more to geobiochemistry, and rare bacteria, which serve as a seed bank for diversity. Our results show that abundant bacterial communities were more sensitive to changing conditions in the early stages of deglaciation than rare community members. Moreover, among the environmental parameters tested, which included total organic carbon, pH, and moisture of the soils, ice thickness was the most influential factor affecting the community structure of abundant bacteria. These results show the different effects of abundant and rare bacteria on community shifts and highlight ice thickness as the primary factor affecting the bacterial community in the early stages of deglaciation. The response of microbial community to climate change can be predicted with more certainty in this polar region.

Highlights

Worldwide deglaciation due to global warming has received much attention in the investigation of microbial diversity and adaptability in recent decades (Bradley et al, 2014)
Samples were collected from the glacier foreland in Larsemann Hills, East Antarctica (Figure 1)
By employing the strategy of space-for-time substitution, the succession of the bacterial community was studied in the glacier foreland in Larsemann Hills, East Antarctica

Summary

Introduction

Worldwide deglaciation due to global warming has received much attention in the investigation of microbial diversity and adaptability in recent decades (Bradley et al, 2014). The deglaciation process exposes terrestrial ecosystems that have been previously locked under ice for thousands of years, providing a unique opportunity to explore the response of the microbial community to climate-driven environmental changes. The gradually exposed soil is subject to wind, solar radiation, rain, snow, and aeolian inputs of particles and organic materials; the soil properties gradually change in the glacier foreland. The C, N and ion contents change because of melt water and increases in temperature (Zumsteg et al, 2012). Light and radiation increase after the covering ice is melted (Kaufmann, 2002), and with the dramatic daily temperature changes in the summertime, freeze-thaw cycles occur in the foreland (Kuhn, 2001). Understanding the changes in microbial communities in connection with soil exposure and environmental parameters can help to predict the response of bacterial communities to changing environmental conditions during the deglaciation process

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