Carbon dioxide outgassing from Amazonian aquatic ecosystems in the Negro River basin

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• 作者：Vinicius Scofield ; John M. Melack ; Pedro M. Barbosa…
• 刊名：Biogeochemistry
• 出版年：2016
• 出版时间：August 2016
• 年：2016
• 卷：129
• 期：1-2
• 页码：77-91
• 全文大小：717 KB
• 刊物类别：Earth and Environmental Science
• 刊物主题：Earth sciences
  Geochemistry
  Biochemistry
  Soil Science and Conservation
  Terrestrial Pollution
  
• 出版者：Springer Netherlands
• ISSN：1573-515X
• 卷排序：129

文摘

Outgassing of biogenic gases from river systems is observed widely, and tropical rivers and their extensive floodplains are likely to be large sources. By combining the first regional survey of CO₂ outgassing from rivers and floodplains in the Amazonian Negro River basin with areal coverage of habitats, we demonstrate large CO₂ fluxes from these dissolved organic carbon-rich waters. We conducted measurements of pCO₂ and calculations of CO₂ outgassing from the water to the atmosphere in river channels and floodplains, including seasonally flooded forests (igapó) and shrubs (campinas), of the Negro River and 21 of its tributaries, in both high (2011) and low (2012) water phases. CO₂ outgassing averaged 96 ± 48 mmol C m−2 day−1 during low water and 253 ± 193 mmol C m−2 day−1 during high water. We observed lower rates of CO₂ outgassing in vegetated habitats in comparison to the river channels, due mainly to lower wind speeds. Regional CO₂ outgassing was determined based on average CO₂ emissions in each habitat and the area covered by each category of aquatic habitat in the basin. Our estimate of total CO₂ emission from the basin is 35.1 ± 4.3 Tg C year−1. These results add to the current understanding of the role of Amazonian rivers and floodplains in local, regional and global estimates CO₂ emission from inland aquatic ecosystems.KeywordsAmazon basinNegro River basinCarbon dioxideCO₂ outgassingTropical aquatic ecosystems