大型水生植物的入侵对一个小热带湖泊温室气体排放量的抑制作用

Invasive floating macrophytes reduce greenhouse gas emissions from a small tropical lake

Floating macrophytes, including water hyacinth (Eichhornia crassipes), are dominant invasive organisms in tropical aquatic systems, and they may play an important role in modifying the gas exchange between water and the atmosphere. However, these systems are underrepresented in global datasets of greenhouse gas (GHG) emissions. This study investigated the carbon (C) turnover and GHG emissions from a small (0.6 km²) water-harvesting lake in South India and analysed the effect of floating macrophytes on these emissions. We measured carbon dioxide (CO₂) and methane (CH₄) emissions with gas chambers in the field as well as water C mineralization rates and physicochemical variables in both the open water and in water within stands of water hyacinths. The CO₂ and CH₄ emissions from areas covered by water hyacinths were reduced by 57% compared with that of open water. However, the C mineralization rates were not significantly different in the water between the two areas. We conclude that the increased invasion of water hyacinths and other floating macrophytes has the potential to change GHG emissions, a process that might be relevant in regional C budgets.

 

大型水生植物，包括水风信子(Eichhornia crassipes)，是热带水生系统中主要的入侵生物之一，它们在改变水与大气之间的气体交换方面可能起着重要的作用。然而，这个系统在温室气体(GHG)排放的全球数据中起到的作用被部分忽视了。本文研究了南印度一个小(0.6 km2)水收集湖的碳(C)流动和温室气体排放，并分析了水生植物对这些排放的影响。我们测量了二氧化碳(CO₂)和甲烷(CH₄)的排放量，以及在水葫芦群落附近的水分与开放水域中水分的C矿化率和物理化学变量。水葫芦群落附近的CO₂和CH₄排放量比开放水域减少了57%。然而，在这两个区域的水中，C矿化率没有明显的差异。我们的结论是，水风信子和其他漂浮的大型植物的入侵有可能改变温室气体排放，这一过程可能与区域的C预算有关。