Science2014-06-10 4:50 PM

二氧化碳浓度上升 土壤微生物分解碳速度加快 Faster Decomposition Under Increased Atmospheric CO2 Limits Soil Carbon Storage

论文摘要 

大多数的地球系统模型估计,大气二氧化碳的增加会刺激光合作用,造成植物摄取更多的二氧化碳,而这转而降低了空气中二氧化碳的浓度。但人们对增高的大气二氧化碳浓度是否也会影响土壤中碳的分解速度则不太清楚(土壤中的碳是通过植物腐败而被输送到那里的)。有人曾经提出,空气中升高的二氧化碳确实会影响土壤的碳储存——土壤的碳储存会增加,这对碳截存过程是一种恩赐。

为了弄清楚这一情况,Kees van Groenigen等人对50多个二氧化碳富集实验的结果进行了检查并用一个土壤碳循环模型来解读它们。在草原、森林及农田的研究中,他们发现,二氧化碳的富集会增加土壤中碳的分解,其速度大致与通过植物腐烂而加回土壤碳的速度相同。van Groenigen及其同事对发生这些事件的过程中的某些进行了讨论。

文章的作者说,此外,他们的研究显示,这些过程会以全球性的规模发生,而这是一个及时到来的信息,因为二氧化碳对土壤碳分解的影响迄今为止还未被纳入到地球系统的模型之中。文章的作者提出,由于它们未被纳入这些模型,因此科学家们可能会对在大气二氧化碳浓度增高的情况下有多少碳被截存在土壤之中做出过高的估计。

 
Abstract 

Soils contain the largest pool of terrestrial organic carbon (C) and are a major source of atmospheric carbon dioxide (CO2). Thus, they may play a key role in modulating climate change. Rising atmospheric CO2 is expected to stimulate plant growth and soil C input but may also alter microbial decomposition. The combined effect of these responses on long-term C storage is unclear. Combining meta-analysis with data assimilation, we show that atmospheric CO2 enrichment stimulates both the input (+19.8%) and the turnover of C in soil (+16.5%). The increase in soil C turnover with rising CO2 leads to lower equilibrium soil C stocks than expected from the rise in soil C input alone, indicating that it is a general mechanism limiting C accumulation in soil.

Editor's Summary

Increasing Turnover

Rising concentrations of CO2 in the atmosphere are likely to stimulate plant growth, leading to increased biomass and soil carbon stocks, thereby lessening the rate of the rise in atmospheric CO2 levels. Van Groenigen et al. (p. 508, published online 24 April) report the results of a meta-analysis and modeling that show that increasing the concentration of atmospheric CO2 also stimulates microbial decomposition of organic carbon in soils, by roughly the same amount that it increases soil organic carbon, leading to lower equilibrium soil carbon inventories and limiting the accumulation of carbon. Thus, soils may not provide as much carbon storage as hoped.

KEYWORDS

SHARE & LIKE

COMMENTS

ABOUT THE AUTHOR

Science

Science Magazine

0 Following 18 Fans 0 Projects 236 Articles

SIMILAR ARTICLES

AbstractThe conservation of sleep across all animal species suggests that sleep serves a vital function. We here report that sleep has a critical funct

Read More

Introduction Recent decades have seen a major international effort to inventory tree communities in the Amazon Basin and Guiana Shield (Amazonia), but

Read More

IntroductionInitiation of protein synthesis is a key step in the control of gene expression. In eukaryotes, initiation is a highly complex process that

Read More

Abstract For decades, social psychological theories have posited that the automatic processes captured by implicit measures have implications for soci

Read More

论文摘要动物界最复杂的眼睛可以在物种口足类甲壳动物(濑尿虾)中找到,其中一些有12种不同类型的光感受器,每种各取样较窄的一组波长,范围包含了深紫外光到远红光(300到720纳米)。在功能上,这种彩色复杂性被视作是谜。当3种或4种色彩通道对色彩辨认来说已经足够时,为何要使用12种色彩通道?对口足类动物行

Read More

论文摘要 首先,在一篇“评论”文章中,Thomas Piketty 和 Emmanuel Saez用“世界顶级收入数据库(WTID)”来比较这两个数值多年来是如何在欧洲和美国演变的;WTID包括了一个世纪之久的有关全球收入的数据以及2个世纪之久的有关个人财富的数据。据研究人员披露,在20世纪之交的时候

Read More

IntroductionCensorship has a long history in China, extending from the efforts of Emperor Qin to burn Confucian texts in the third century BCE to the c

Read More

Many animals, on air, water, or land, navigate in three-dimensional (3D) environments, yet it remains unclear how brain circuits encode the animal's 3D

Read More

Many animals, on air, water, or land, navigate in three-dimensional (3D) environments, yet it remains unclear how brain circuits encode the animal's 3D

Read More

Like mammalian neurons, Caenorhabditis elegans neurons lose axon regeneration ability as they age, but it is not known why. Here, we report that let-7

Read More