Dimethyl sulfide in the Amazon rain forest
Dimethyl sulfide in the Amazon rain forest
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DOI：
10.1002/2014gb004969
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发表时间：
2015-01-01
影响因子：
5.2
通讯作者：
Andreae, M. O.
中科院分区：
文献类型：
--
作者：
Jardine, K.;Yanez-Serrano, A. M.;Andreae, M. O.
二甲基硫醚（DMS）的地表至大气排放可能会通过形成气态硫酸影响全球气候，这可能会产生次生硫酸盐气溶胶，并有助于形成新的颗粒。虽然海洋通常被认为是二甲硫醚的主要来源，但由于缺乏生态系统观测，无法对陆地二甲硫醚来源进行准确分析。使用质谱仪，我们量化了亚马逊盆地中部主要雨林生态系统内部和上方的环境DMS混合比，实时（2010-2011）和高垂直分辨率（2013-2014）。在树冠层内观察到的二甲基硫混合比升高，但变化很大，这表明在旱季和雨季的白天和夜晚，大气中存在明显的生态系统净源。在许多夜晚，高DMS混合比的时期持续长达8小时（高达万亿分之160（ppt）），经常发生在冠层内和表面附近。白天的梯度显示混合比（高达80 ppt）峰值附近的树冠顶部以及近地面以下的降雨事件。二甲硫醚的空间和时间分布表明，当地土壤和植物的排放量决定了环境水平及其潜在的气候影响。一个土壤源被证实的测量DMS排放通量从亚马逊土壤作为温度和土壤湿度的函数。此外，光和温度依赖的DMS排放量进行了测量，从七个热带树种。我们的研究对于理解陆地DMS源及其在耦合陆-气气候反馈中的作用具有重要意义。
Surface-to-atmosphere emissions of dimethyl sulfide (DMS) may impact global climate through the formation of gaseous sulfuric acid, which can yield secondary sulfate aerosols and contribute to new particle formation. While oceans are generally considered the dominant sources of DMS, a shortage of ecosystem observations prevents an accurate analysis of terrestrial DMS sources. Using mass spectrometry, we quantified ambient DMS mixing ratios within and above a primary rainforest ecosystem in the central Amazon Basin in real-time (2010-2011) and at high vertical resolution (2013-2014). Elevated but highly variable DMS mixing ratios were observed within the canopy, showing clear evidence of a net ecosystem source to the atmosphere during both day and night in both the dry and wet seasons. Periods of high DMS mixing ratios lasting up to 8h (up to 160parts per trillion (ppt)) often occurred within the canopy and near the surface during many evenings and nights. Daytime gradients showed mixing ratios (up to 80ppt) peaking near the top of the canopy as well as near the ground following a rain event. The spatial and temporal distribution of DMS suggests that ambient levels and their potential climatic impacts are dominated by local soil and plant emissions. A soil source was confirmed by measurements of DMS emission fluxes from Amazon soils as a function of temperature and soil moisture. Furthermore, light- and temperature-dependent DMS emissions were measured from seven tropical tree species. Our study has important implications for understanding terrestrial DMS sources and their role in coupled land-atmosphere climate feedbacks.