Quan T M, Falkowski P G
Institute of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ 08901, USA.
Geobiology. 2009 Mar;7(2):124-39. doi: 10.1111/j.1472-4669.2008.00182.x. Epub 2008 Dec 18.
The ratio of dissolved fixed inorganic nitrogen to soluble inorganic phosphate (N:P) in the ocean interior is relatively constant, averaging approximately 16 : 1 by atoms. In contrast, the ratio of these two elements spans more than six orders of magnitude in lakes and other aquatic environments. To understand the factors influencing N:P ratios in aquatic environments, we analyzed 111 observational datasets derived from 35 water bodies, ranging from small lakes to ocean basins. Our results reveal that N:P ratios are highly correlated with the concentration of dissolved O(2) below approximately 100 micromol L(-1). At higher concentrations of O(2), N:P ratios are highly variable and not correlated with O(2); however, the coefficient of variation in N:P ratios is strongly related to the size of the water body. Hence, classical Redfield ratios observed in the ocean are anomalous; this specific elemental stoichiometry emerges not only as a consequence of the elemental ratio of the sinking flux of organic matter, but also as a result of the size of the basins and their ventilation. We propose that the link between N:P ratios, basin size and oxygen levels, along with the previously determined relationship between sedimentary delta(15)N and oxygen, can be used to infer historical N:P ratios for any water body.
海洋内部溶解的固定无机氮与可溶性无机磷的比例（N:P）相对恒定，按原子计算平均约为16:1。相比之下，在湖泊和其他水生环境中，这两种元素的比例跨度超过六个数量级。为了了解影响水生环境中N:P比例的因素，我们分析了来自35个水体的111个观测数据集，这些水体从小湖泊到海洋盆地不等。我们的结果表明，当溶解氧浓度低于约100微摩尔/升时，N:P比例与溶解氧浓度高度相关。在较高的溶解氧浓度下，N:P比例变化很大且与溶解氧不相关；然而，N:P比例的变异系数与水体大小密切相关。因此，在海洋中观察到的经典雷德菲尔德比例是反常的；这种特定的元素化学计量比不仅是有机物质下沉通量的元素比例的结果，也是盆地大小及其通风情况的结果。我们提出，N:P比例、盆地大小和氧含量之间的联系，以及先前确定的沉积δ(15)N与氧之间的关系，可用于推断任何水体的历史N:P比例。
