Analysis of nitrogen and phosphorus transfer through aquatic food webs.

为了研究碳、氮、磷在水环境中通过食物网的转移过程，测定了不同浮游生物体内碳、氮、磷的含量。两个研究地点，作为富营养化沃茨和奥多玉湖的富营养化的一个例子，被选中，以获得浮游生物样品。在实验室研究中，评估了氮和磷对细菌、浮游植物和浮游动物生长和繁殖的影响，并考虑了食物网的作用。以下资料是从浮游生物大小分级样本的化学分析中获得的。1.一般而言，L的N/C和P/C比率较高。Suwa样品中的含量高于L.奥玉2.这两个比例较高的浮游动物比浮游植物; 2倍的N/C和4倍的P/C，这表明浓缩的元素在其放牧活动的必要性。3.细菌细胞中的C和N含量估计为0.06至0.19 pgC/um细胞体积和0.203的平均N/C比。使用H胸苷摄取的实验表明，磷是一种限制营养素的细菌生产在贫营养湖泊。浮游植物生产量受P和N的控制。浮游动物的生长和元素组成受饵料浮游植物氮、磷含量的影响，尤其是在低浓度饵料条件下。这些结果表明，细菌和浮游动物并不一定像以前认为的那样在水生环境中发挥营养再生的作用。

In order to study the processes of carbon(C), nitrogen(N) and phosphorus(P) transfer through food webs in aquatic environments, contents of these elements in various plankton organisms were determined. Two study sites, Lake Ouwa as an example of eutrophic waters and lake okutama as oligotrophic ones, were selected to obtain planktonic samples. In laboratory studies the effects of nitrogen and phosphorus on the growth and production of bacteria, phytoplankton and zooplankton were assessed and the role of food webs was considered. The following information was obtained from the chemical analysis of size fractionated plankton samples. 1. Generally, higher N/C and P/C rations were recorded in L. Suwa samples than those from L. Okutama. 2. These two ratios were higher in zooplankton than phytoplankton; two times in N/C and four times in P/C, suggesting the necessity of condensation of the elements in their grazing activity. 3. C and N contents in bacterial cells were estimated; 0.06 to 0.19 pgC/um cell volume and 0.203 in mean N/C ratio. An experiment using H thymidine uptake revealed that phosphorus was a limiting nutrient for bacterial production in an oligotrophic lake. It was also shown phytoplankton production was controlled by P and N. The growth and element composition of zooplankton were affected by N and P-content of food phytoplankton especially under low food concentration. These results show that bacteria and zooplankton do not necessarily play the role of nutrient regeneration in aquatic environments as previously believed.