A possible role of ground-based microorganisms on cloud formation in the atmosphere
A possible role of ground-based microorganisms on cloud formation in the atmosphere
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DOI：
10.5194/bg-7-387-2010
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发表时间：
2010-01-01
期刊：
影响因子：
4.9
通讯作者：
Artaxo, P.
中科院分区：
文献类型：
--
作者：
Ekstrom, S.;Noziere, B.;Artaxo, P.
云的形成是大气、水文循环和气候的一个重要过程，但它的某些方面还没有完全了解。在这项工作中，我们表明，微生物可能会影响云的形成，而不离开地球表面释放生物表面活性剂（或生物表面活性剂）在环境中，使他们的方式进入大气气溶胶，并可以显着提高他们的激活成云滴。在这项工作的第一部分，对标准生物表面活性剂的云雾成核效率进行了表征，发现其优于迄今为止研究的任何气溶胶材料，包括无机盐。这些结果确定了赋予有机化合物特殊的云成核特性的分子结构。在第二部分中，在不同的地点：温带沿海站点，海洋站点，温带森林和热带森林的大气气溶胶进行了采样。测量了它们的表面张力，发现低于30 mN/m，据我们所知，这是气溶胶的最低报告。这种非常低的表面张力是由于存在的生物表面活性剂，唯一的天然物质能够达到如此低的values.The存在的强大的微生物表面活性剂在气溶胶中将是一致的有机馏分的特殊的云成核效率最近发现的气溶胶，并与藻类水华和云量之间的相关性在南大洋报道。这项工作的结果还表明，生物表面活性剂可能是常见的气溶胶，因此具有全球意义。如果这一点得到证实，就可以确定微生物在大气和气候中的新作用。
The formation of clouds is an important process for the atmosphere, the hydrological cycle, and climate, but some aspects of it are not completely understood. In this work, we show that microorganisms might affect cloud formation without leaving the Earth's surface by releasing biological surfactants (or biosurfactants) in the environment, that make their way into atmospheric aerosols and could significantly enhance their activation into cloud droplets.In the first part of this work, the cloud-nucleating efficiency of standard biosurfactants was characterized and found to be better than that of any aerosol material studied so far, including inorganic salts. These results identify molecular structures that give organic compounds exceptional cloud-nucleating properties. In the second part, atmospheric aerosols were sampled at different locations: a temperate coastal site, a marine site, a temperate forest, and a tropical forest. Their surface tension was measured and found to be below 30 mN/m, the lowest reported for aerosols, to our knowledge. This very low surface tension was attributed to the presence of biosurfactants, the only natural substances able to reach to such low values.The presence of strong microbial surfactants in aerosols would be consistent with the organic fractions of exceptional cloud-nucleating efficiency recently found in aerosols, and with the correlations between algae bloom and cloud cover reported in the Southern Ocean. The results of this work also suggest that biosurfactants might be common in aerosols and thus of global relevance. If this is confirmed, a new role for microorganisms on the atmosphere and climate could be identified.