Global reduction of in situ CO2 transfer velocity by natural surfactants in the sea-surface microlayer
Global reduction of in situ CO2 transfer velocity by natural surfactants in the sea-surface microlayer
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DOI：
10.1098/rspa.2019.0763
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发表时间：
2020-02
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影响因子：
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通讯作者：
N. I. H. Mustaffa;M. Ribas-Ribas-M.-Ribas-Ribas-1404072844;Hanne M. Banko-Kubis;O. Wurl
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文献类型：
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作者：
N. I. H. Mustaffa;M. Ribas-Ribas-M.-Ribas-Ribas-1404072844;Hanne M. Banko-Kubis;O. Wurl
几十年来，海洋表面微层（SML）中的表面活性剂对气体传输速度（k）的影响已被认识到;然而，由于缺少二氧化碳（CO2）原位k和SML表征的相关数据，在自然条件下尚未对其进行量化。此外，在海洋中经常观察到一种称为浮油的海面减波现象，这种现象有可能减少海洋和大气之间与气候有关的气体的转移。因此，本研究旨在量化天然表面活性剂和浮油对CO2原位k的影响。一个双体船，海面扫描仪（S3），部署到采样的SML和相应的下伏水，和一个漂流浮标与浮动室部署到现场测量CO2的k。我们发现，在表面活性剂浓度为200 µg Teq l−1以上，k值显著降低了23%，这在除西太平洋以外的SML中很常见。我们的结论是，在西太平洋的CO2通量的误差约为20%，是由应用风为基础的参数化不发达国家在低表面活性剂制度。此外，我们还观察到天然浮油减少了62%，考虑到已知的浮油覆盖频率，全球二氧化碳通量减少了19%。从我们的观察，我们确定了表面活性剂浓度与两个不同的端员，导致全球CO2通量估计的错误，如果忽略。
For decades, the effect of surfactants in the sea-surface microlayer (SML) on gas transfer velocity (k) has been recognized; however, it has not been quantified under natural conditions due to missing coherent data on in situ k of carbon dioxide (CO2) and characterization of the SML. Moreover, a sea-surface phenomenon of wave-dampening, known as slicks, has been observed frequently in the ocean and potentially reduces the transfer of climate-relevant gases between the ocean and atmosphere. Therefore, this study aims to quantify the effect of natural surfactant and slicks on the in situ k of CO2. A catamaran, Sea Surface Scanner (S3), was deployed to sample the SML and corresponding underlying water, and a drifting buoy with a floating chamber was deployed to measure the in situ k of CO2. We found a significant 23% reduction of k above surfactant concentrations of 200 µg Teq l−1, which were common in the SML except for the Western Pacific. We conclude that an error of approximately 20% in CO2 fluxes for the Western Pacific is induced by applying wind-based parametrization not developed in low surfactant regimes. Furthermore, we observed an additional 62% reduction in natural slicks, reducing global CO2 fluxes by 19% considering known frequency of slick coverage. From our observation, we identified surfactant concentrations with two different end-members which lead to an error in global CO2 flux estimation if ignored.