Exotic Spartina alterniflora invasion increases CH4 while reduces CO2 emissions from mangrove wetland soils in southeastern China

Gui Feng Gao,Ying Ying Qin,Kabir Ghoto,Peng Fei Li,Xue Yi Zhu,Hai Lei Zheng,Zhi Jun Shen,Xi Min Zhang

doi:10.1038/s41598-018-27625-5

Gui Feng Gao, Ying Ying Qin + Show 6 more

Open Access

https://doi.org/10.1038/s41598-018-27625-5

Copy DOI

Abstract

Mangroves are critical in global carbon budget while vulnerable to exotic plant invasion. Spartina alterniflora, one of typical salt marsh plant grows forcefully along the coast of China, has invaded the native mangrove habitats in Zhangjiang Estuary. However, the effects of S. alterniflora invasion on soil carbon gases (CH4 and CO2) emission from mangroves are not fully understood. Accordingly, we conducted a field experiment to investigate the soil CH4 and CO2 emission during growing seasons in 2016 and 2017 at four adjacent wetlands, namely bare mudflat (Mud), Kandelia obovata (KO), Avicennia marina (AM) and S. alterniflora (SA). Potential methane production (PMP), potential methane oxidation (PMO), functional microbial abundance and soil biogeochemical properties were measured simultaneously. Our results indicate that S. alterniflora invasion could dramatically increase soil CH4 emissions mainly due to the enhancement in PMP which facilitated by soil EC, MBC, TOC and mcrA gene abundance. Additionally, S. alterniflora invasion decreases soil CO2 emission. Both heterotrophic microbial respiration (16S rRNA) and methane oxidation (pmoA and ANME-pmoA) are responsible for CO2 emission reduction. Furthermore, S. alterniflora invasion greatly increases GWP by stimulating CH4 emissions. Thus, comparing with mangroves, invasive S. alterniflora significantly (p < 0.001) increases CH4 emission while reduces CO2 emission.

Highlights

The concentrations of atmospheric carbon gases have drastically increased since the industrial era, playing a pivotal role in global climate change[1]
As the rapid expansion of S. alterniflora in mangrove wetlands in China, there is an urgent need to reveal the soil carbon gases emission from mangroves as well as its driven factors according to S. alterniflora invasion
A field study was conducted during growing seasons (May, Jun and Jul) in 2016 and 2017 at Zhangjiang Mangrove Estuary to investigate soil carbon gases (CH4 and CO2) emission at four adjacent sites, namely bare mudflat (Mud), Kandelia obovata (KO), Avicennia marina (AM) and S. alterniflora (SA)

Summary

Introduction

The concentrations of atmospheric carbon gases (mainly CO2 and CH4) have drastically increased since the industrial era, playing a pivotal role in global climate change[1]. Many studies have been conducted to investigate the soil greenhouse gas emission from S. alterniflora salt marsh ecosystems[6,19,20,21,22,23], there are very little agreements on the effects of S. alterniflora invasion on soil carbon gases emission. CH4 emission from S. alterniflora and mangrove Kandelia obovata sites are comparable, which are higher than that from bare mudflat in JRMR8 This inconsistency implies that the effects of S. alterniflora invasion on soil carbon cycle are complicated. A field study was conducted during growing seasons (May, Jun and Jul) in 2016 and 2017 at Zhangjiang Mangrove Estuary to investigate soil carbon gases (CH4 and CO2) emission at four adjacent sites, namely bare mudflat (Mud), Kandelia obovata (KO), Avicennia marina (AM) and S. alterniflora (SA). Soil functional microbial abundance (16S rRNA, pmoA, ANME-pmoA and M. oxyfera-pmoA), potential methane production (PMP), potential methane oxidation (PMO), extracellular enzyme activities (invertase and β-glucosidase activity) and other biogeochemical properties (TOC, MBC and so on) were measured simultaneously

Objectives

Methods

Results

Conclusion