生物谷Bioon.com 讯 科研人员报告说，全世界大陆上的储碳植物物质量在过去的十年中有所下降，从而逆转了过去20年的趋势。 据Maosheng Zhao 和 Steven Running披露，大面积干旱看来与这一下降有关。这些干旱所发生的时间是自1880年代有仪器开始测量温度以来的最暖和的几十年。

陆地“净初级生产力”（或称“NPP”，它指的是由植物加以固定并以生物量积聚的碳量）从1982年直至1999年都在增加，这一趋势可能得到了在大气中增加的二氧化碳浓度的支持。

该研究的作者通过分析来自安装在美国宇航局（NASA）的地神（Terra）卫星上的中分辨率成像光谱仪（MODIS）卫星数据加上全球气候数据来调查从2000-2009年的陆地净初级生产力（NPP）和气候的变化。

他们发现，全球净初级生产力（NPP）在过去的十年中略有下降，而地区性的主要原因则是干旱。

尽管较为暖和的温度导致了高纬度及高海拔地区的净初级生产力（NPP）的某些增加，但在雨林中（雨林保持着世界上大多数的植物物质），较高的气温因为水分胁迫及植物呼吸（植物呼吸会将碳返回到大气之中）而限制了净初级生产力（NPP）。（生物谷Bioon.com）

生物谷推荐原文出处：

Science DOI: 10.1126/science.1192666

Drought-Induced Reduction in Global Terrestrial Net Primary Production from 2000 Through 2009
Maosheng Zhao* and Steven W. Running

Terrestrial net primary production (NPP) quantifies the amount of atmospheric carbon fixed by plants and accumulated as biomass. Previous studies have shown that climate constraints were relaxing with increasing temperature and solar radiation, allowing an upward trend in NPP from 1982 through 1999. The past decade (2000 to 2009) has been the warmest since instrumental measurements began, which could imply continued increases in NPP; however, our estimates suggest a reduction in the global NPP of 0.55 petagrams of carbon. Large-scale droughts have reduced regional NPP, and a drying trend in the Southern Hemisphere has decreased NPP in that area, counteracting the increased NPP over the Northern Hemisphere. A continued decline in NPP would not only weaken the terrestrial carbon sink, but it would also intensify future competition between food demand and proposed biofuel production.

Numerical Terradynamic Simulation Group, Department of Ecosystem and Conservation Sciences, the University of Montana, Missoula, MT 59812, USA.