Greenhouse gas emissions from streams at North Temperate Lakes LTER 2012

Aquatic ecosystems can be important components of landscape carbon budgets. In lake-rich landscapes, streams may be important sources of greenhouse gases (CO2 and CH4) to the atmosphere in addition to lakes, but their source strength is poorly documented. The processes which control gas concentrations and emissions in these interconnected landscapes of lakes, streams and groundwater have not been adequately addressed. In this paper we use multiple datasets that vary in their spatial and temporal extent to investigate the carbon gas source strength of streams in a lake-rich landscape and to determine the roles of lakes and groundwater. We show that streams emit roughly the same mass of CO2 as regional lakes, and that stream CH4 emissions are an important component of the regional greenhouse gas balance.

水生生态系统是景观碳收支的重要组成部分。在多湖泊景观中，溪流除湖泊外，亦可能是向大气排放温室气体（二氧化碳CO₂、甲烷CH₄）的重要源，但学界对其源强度的记载仍较为匮乏。调控由湖泊、溪流与地下水构成的互联景观中气体浓度与排放的相关过程，尚未得到充分研究。本研究依托多套时空尺度各异的数据集，探究多湖泊景观中溪流的碳气体源强度，并厘清湖泊与地下水所扮演的角色。研究结果表明，溪流的二氧化碳排放总量与区域湖泊大致相当，而溪流的甲烷排放亦是区域温室气体收支的重要组成部分。