Microorganisms are but a few micrometers in diameter and are not visible to the naked eye. Yet, the large numbers of microorganisms present in the oceans and the global impact of their activities make it possible to observe them from space. Here a few examples of how microorganisms can be studied from satellites are presented. The first case is the best known: the main pigment used in photosynthesis (chlorophyll a) can be determined from satellites. These kinds of studies have contributed a tremendous amount of understanding about the distribution and dynamics of primary production in the oceans. Two other examples will concern analysis of heterotrophic prokaryotic production and estimates of dimethyl sulfide (DMS) concentration and flux to the atmosphere. These three processes are of fundamental importance for the functioning of the biosphere. Marine microbes carry out about half of the total primary production in the planet. A substantial fraction of the respiration in the oceans is due to the activity of heterotrophic prokaryotes. Finally, the flux of DMS to the atmosphere is believed to constitute one of the mechanisms by which the biota can regulate climate. The global implications of microbial processes in the oceans can only be addressed with the help of satellites.

中文翻译：

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从太空研究海洋微生物。

微生物的直径只有几微米，肉眼看不到。然而，海洋中存在大量的微生物及其活动的全球影响，使得有可能从太空对其进行观察。这里介绍了如何从卫星研究微生物的一些例子。第一种情况是众所周知的：光合作用中使用的主要色素（叶绿素a）可以通过卫星确定。这些研究为人们对海洋初级生产的分布和动力学的理解做出了巨大的贡献。其他两个例子将涉及对异养原核生物产生的分析以及对二甲基硫（DMS）浓度和通向大气通量的估计。这三个过程对于生物圈的功能至关重要。海洋微生物约占地球初级生产总量的一半。海洋中大部分的呼吸作用是由于异养原核生物的活动引起的。最后，DMS向大气的通量被认为是生物群调节气候的机制之一。