ÂÛÎÄÌâÄ¿: Perturbation-free Measurement of in situ Di-nitrogen Emissions from Denitrification in Nitrate-rich Aquatic Ecosystems

ÂÛÎıàºÅ:
×÷Õß: Shuping Qin£¨ÇØÊ÷ƽ£©,Timothy Clough, Jiafa Luo, Nicole Wrage-M€onnig, Oene Oenema, Yuming Zhang£¨ÕÅÓñÃú£©,Chunsheng Hu£¨ºú´ºÊ¤£©
¿¯ÎïÃû³Æ: Water Research
¾íÆÚÒ³Âë: Volume 109, , Pages 94¨C101
·¢±íÄê¶È: 2017
DOI: http://dx.doi.org/10.1016/j.watres.2016.11.035
ÕªÒª:

Increased production of reactive nitrogen (Nr) from atmospheric di-nitrogen (N₂) has greatly contributed to increased food production. However, enriching the biosphere with Nr has also caused a series of negative effects on global ecosystems, especially aquatic ecosystems. The main pathway converting Nr back into the atmospheric N₂pool is the last step in the denitrification process. Despite several attempts, there is still a need for perturbation-free methods for measuringin situN₂fluxes from denitrification in aquatic ecosystems at the field scale. Such a method is needed to comprehensively quantify the N₂fluxes from aquatic ecosystems. Here we observed linear relationships between the ¦Ä¹⁵N-N₂O signatures and the logarithmically transformed N₂O/(N₂+N₂O) emission ratios. Through independent measurements, we verified that the perturbation-free N₂flux from denitrification in nitrate-rich aquatic ecosystems can be inferred from these linear relationships. Our method allowed the determination of field-scalein situN₂fluxes from nitrate-rich aquatic ecosystems both with and without overlaying water. The perturbation-freein situN₂fluxes observed by the new method were almost one order of magnitude higher than those by the sediment core method. The ability of aquatic ecosystems to remove Nr may previously have been severely underestimated.