Warmer temperature accelerates methane emissions from the Zoige wetland on the Tibetan Plateau without changing methanogenic community composition

Mengmeng Cui,Anzhou Ma,Hongyan Qi,Xuliang Zhuang,Guoqiang Zhuang,Guohui Zhao

doi:10.1038/srep11616

Abstract

Zoige wetland, locating on the Tibet Plateau, accounts for 6.2% of organic carbon storage in China. However, the fate of the organic carbon storage in the Zoige wetland remains poorly understood despite the Tibetan Plateau is very sensitive to global climate change. As methane is an important greenhouse gas and methanogenesis is the terminal step in the decomposition of organic matter, understanding how methane emissions from the Zoige wetland is fundamental to elucidate the carbon cycle in alpine wetlands responding to global warming. In this study, microcosms were performed to investigate the effects of temperature and vegetation on methane emissions and microbial processes in the Zoige wetland soil. A positive correlation was observed between temperature and methane emissions. However, temperature had no effect on the main methanogenic pathway—acetotrophic methanogenesis. Moreover, methanogenic community composition was not related to temperature, but was associated with vegetation, which was also involved in methane emissions. Taken together, these results indicate temperature increases methane emissions in alpine wetlands, while vegetation contributes significantly to methanogenic community composition and is associated with methane emissions. These findings suggest that in alpine wetlands temperature and vegetation act together to affect methane emissions, which furthers a global warming feedback loop.

Highlights

The role of temperature as an influencing factor on CH4 emissions from wetlands is important in light of the potential for climate change-associated global warming
There have been few studies that focus on the effects of global warming on CH4 emissions from the Zoige wetland, even though it is the largest highland wetland in the world and is located on the Tibet Plateau[10], an ideal place for global warming study due to its susceptibleness to climate change[11]
Different rates of CH4 emissions have been observed from wetlands dominated by different plants, which demonstrates that the vegetation community composition plays an important role in CH4 emissions[15,16]

Summary

Introduction

There is potential for the Zoige wetland to release its stored carbon as additional CO2 and CH4 into the atmosphere, forming a positive feedback loop through increases in greenhouse emissions. In this manner, it may accelerate global warming, contributing to a negative cycle of global climate change. Climate change can have a profound effect on vegetation community composition[17] Changes in this community composition in response to global warming may further alter CH4 emission from wetlands. In an attempt to isolate the effect of temperature, all incubations were performed under uniform anaerobic conditions

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