Nitrous Oxide Emissions from Intertidal Zone of the Yellow River Estuary in Autumn and Winter During 2011–2012

详细信息    查看全文

• 作者：Wenguang Sun ; Zhigao Sun ; Xiaojie Mou ; Wanlong Sun ; Xingyun Hu
• 关键词：Nitrous oxide emission ; Spatial and temporal variation ; Intertidal zone ; Yellow River estuary
• 刊名：Estuaries and Coasts
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：40
• 期：1
• 页码：145-159
• 全文大小：
• 刊物类别：Earth and Environmental Science
• 刊物主题：Environment, general; Ecology; Freshwater & Marine Ecology; Environmental Management; Coastal Sciences; Water and Health;
• 出版者：Springer US
• ISSN：1559-2731
• 卷排序：40

文摘

Much uncertainty exists in spatial and temporal variations of nitrous oxide (N₂O) emissions from coastal marshes in temperate regions. To investigate the spatial and temporal variations of N₂O fluxes and determine the environmental factors influencing N₂O fluxes across the coastal marsh dominated by Suaeda salsa in the Yellow River estuary, China, in situ measurements were conducted in high marsh (HM), middle marsh (MM), low marsh (LM), and mudflat (MF) in autumn and winter during 2011–2012. Results showed that mean N₂O fluxes and cumulative N₂O emission indicated intertidal zone of the examined marshes as N₂O sources over all sampling seasons with range of 0.0051 to 0.0152 mg N₂O m−2 h−1 and 7.58 to 22.02 mg N₂O m−2, respectively. During all times of day and the seasons measured, N₂O fluxes from the intertidal zone ranged from −0.0004 to 0.0644 mg N₂O m−2 h−1. The freeze/thaw cycles in sediments during early winter (frequent short-term cycle) and midwinter (long-term cycle) were one of main factors affecting the temporal variations of N₂O emission. The spatial variations of N₂O fluxes in autumn were mainly dependent on tidal fluctuation and plant composition. The ammonia-nitrogen (NH₄+–N) in sediments of MF significantly affected N₂O emissions (p < 0.05), and the high concentrations of Fe in sediments might affect the spatial variation of N₂O fluxes. This study highlighted the large spatial variation of N₂O fluxes across the coastal marsh (coefficient of variation (CV) = 127.86 %) and the temporal variation of N₂O fluxes during 2011–2012 (CV = 137.29 %). Presently, the exogenous C and N loadings of the Yellow River estuary are increasing due to human activities; thus, the potential effects of exogenous C and N loadings on N₂O emissions during early winter should be paid more attention as the N₂O inventory is assessed precisely.