01604nas a2200145   4500008004100000245007000041210006900111300001600180490000600196520112700202100002001329700002301349700002101372856006501393       2019                        eng d00aExploring methods of measuring CO2 degassing in headwater streams0 aExploring methods of measuring CO2 degassing in headwater stream  a1765–17790 v53 a<p>Carbon dioxide (CO2) degassed from ungauged, headwater streams has a significant role in carbon cycling and climate change, making the precise measurement of the degassing of critical importance. Although methods exist for quantifying degassing rates in large bodies of water (seawater, lakes), these methods are often considered invalid for measuring degassing rates in small, turbulent, groundwater fed headwater streams. This manuscript reviews the physics of gas transfer across the stream-atmosphere interface and provides an in-depth critical review of the available methods of measuring CO2 degassing. Further, it discusses applications for some of these methods in small headwater streams and other low-order streams that are dominated by discharged groundwater. Of the methods reviewed, almost all produce fairly low precision and do not compare well with other methods tested in the same location. We suggest much more work is needed to improve the precision and accuracy of field-measured gas transfer coefficients, both by applying multiple methods in the field and by controlled laboratory experiments.</p>1 aRawitch, M., J.1 aMacpherson, G., L.1 aBrookfield, A.E.  uhttps://link.springer.com/article/10.1007/s40899-019-00332-3