水環(huán)境中硝酸鹽的積累（主要由化肥的使用造成）會(huì)造成環(huán)境問題和公共衛(wèi)生問題,。
現(xiàn)在,，Philip Taylor 和 Alan Townsend在土壤,、淡水生態(tài)系統(tǒng)和海洋（包括經(jīng)歷實(shí)質(zhì)性氮加載的生態(tài)系統(tǒng)）的硝酸鹽和有機(jī)碳濃度之間發(fā)現(xiàn)一個(gè)一致的反向關(guān)系。他們發(fā)現(xiàn),，這個(gè)模式可用碳-硝酸鹽比例來解釋,，該比例通過調(diào)控對(duì)溶解的有機(jī)碳和硝酸鹽循環(huán)進(jìn)行耦合的微生物過程影響硝酸鹽積累,。
這些結(jié)果可以為分析全世界生態(tài)系統(tǒng)中硝酸鹽的命運(yùn)及人類干預(yù)的影響提供一個(gè)可以驗(yàn)證的框架。(生物谷Bioon.com)
生物谷推薦原文出處：
Nature doi:10.1038/nature08985
Stoichiometric control of organic carbon–nitrate relationships from soils to the sea
Philip G. Taylor1,2 & Alan R. Townsend1,2
INSTAAR and,Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, USA
The production of artificial fertilizers, fossil fuel use and leguminous agriculture worldwide has increased the amount of reactive nitrogen in the natural environment by an order of magnitude since the Industrial Revolution1. This reorganization of the nitrogen cycle has led to an increase in food production2, but increasingly causes a number of environmental problems1, 3. One such problem is the accumulation of nitrate in both freshwater and coastal marine ecosystems. Here we establish that ecosystem nitrate accrual exhibits consistent and negative nonlinear correlations with organic carbon availability along a hydrologic continuum from soils, through freshwater systems and coastal margins, to the open ocean. The trend also prevails in ecosystems subject to substantial human alteration. Across this diversity of environments, we find evidence that resource stoichiometry (organic carbon:nitrate) strongly influences nitrate accumulation by regulating a suite of microbial processes that couple dissolved organic carbon and nitrate cycling. With the help of a meta-analysis we show that heterotrophic microbes maintain low nitrate concentrations when organic carbon:nitrate ratios match the stoichiometric demands of microbial anabolism. When resource ratios drop below the minimum carbon:nitrogen ratio of microbial biomass4, however, the onset of carbon limitation appears to drive rapid nitrate accrual, which may then be further enhanced by nitrification. At low organic carbon:nitrate ratios, denitrification appears to constrain the extent of nitrate accretion, once organic carbon and nitrate availability approach the 1:1 stoichiometry5 of this catabolic process. Collectively, these microbial processes express themselves on local to global scales by restricting the threshold ratios underlying nitrate accrual to a constrained stoichiometric window. Our findings indicate that ecological stoichiometry can help explain the fate of nitrate across disparate environments and in the face of human disturbance.
