ABSTRACT: Isoprene (2-methyl-1,3-butadiene) is emitted in vast quantities (>500 Tg C yr^-1). Most isoprene is emitted by trees, but there is still incomplete understanding of the diversity of isoprene sources. The reactivity of isoprene in the atmosphere has potential implications for both global warming and global cooling, with human health implications also arising from isoprene-induced ozone formation in urban areas. Isoprene emissions from terrestrial environments have been studied for many years, but our understanding of aquatic isoprene emissions is less complete. Several abundant phytoplankton taxa produced isoprene in the laboratory, and the relationship between chlorophyll a and isoprene production has been used to estimate emissions from marine environments. The aims of this review are to highlight the role of aquatic environments in the biological cycling of isoprene and to stimulate further study of isoprene metabolism in marine and freshwater environments. From a microbial ecology perspective, the isoprene metabolic gene cluster, first identified in Rhodococcus sp. AD45 (isoGHIJABCDEF) and subsequently found in every genome-sequenced isoprene-degrader, provides the ideal basis for molecular studies on the distribution and diversity of isoprene-degrading communities. Further investigations of isoprene-emitting microbes, such as the influence of environmental factors and geographical location, must also be considered when attempting to constrain estimates of the flux of isoprene in aquatic ecosystems. We also report isoprene emission by the scleractinian coral Acropora horrida and the degradation of isoprene by the same coral holobiont, which highlights the importance of better understanding the cycling of isoprene in marine environments.

中文翻译：

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水生生态系统中异戊二烯循环的微生物学

摘要：异戊二烯（2-甲基-1,3-丁二烯）大量排放（>500 Tg C yr ^-1）。大多数异戊二烯是由树木排放的，但对异戊二烯来源的多样性仍不完全了解。异戊二烯在大气中的反应性对全球变暖和全球变冷都有潜在影响，异戊二烯在城市地区引起的臭氧形成也会对人类健康产生影响。陆地环境中的异戊二烯排放已经研究了很多年，但我们对水生异戊二烯排放的理解并不完整。实验室几种丰富的浮游植物类群产生异戊二烯，叶绿素a与异戊二烯的生产已被用于估算海洋环境的排放量。本综述的目的是强调水生环境在异戊二烯生物循环中的作用，并促进对海洋和淡水环境中异戊二烯代谢的进一步研究。从微生物生态学的角度来看，异戊二烯代谢基因簇，首先在红球菌属中发现。AD45 ( isoGHIJABCDEF)，随后在每个基因组测序的异戊二烯降解剂中发现，为异戊二烯降解群落的分布和多样性的分子研究提供了理想的基础。在试图限制对水生生态系统中异戊二烯通量的估计时，还必须考虑对异戊二烯排放微生物的进一步调查，例如环境因素和地理位置的影响。我们还报告了 scleractinian 珊瑚Acropora horrida 的异戊二烯排放以及同一个珊瑚全息生物对异戊二烯的降解，这突出了更好地了解海洋环境中异戊二烯循环的重要性。