Analysis of nitrogen and phosphorus transfer through aquatic food webs.

通过水生食物网进行氮和磷转移的分析。

• 批准号: 62540504
• 负责人: WATANABE Yasunori
• 金额: $ 1.28万
• 依托单位: Faculty of Science, Tokyo Metropolitan University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1987
• 资助国家: 日本
• 起止时间: 1987 至 1988
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-62540504/
• 关键词: Food Webs; Plankton Community; Lake; Geochemical Cycle; Nitrogen ＆ Phosphorus; 水界生態系; プランクトン群集; プランクトン; 窒素; リン; 細菌

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.

为了研究水生环境中碳(C)、氮(N)和磷(P)在食物网中的转移过程，测定了不同浮游生物体内碳(C)、氮(N)和磷(P)的含量。选取富营养化水体为例的欧洼湖和贫营养化水体为例的奥多摩湖两个研究点采集浮游生物样本。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的生长和生产的影响，并考虑了食物网的作用。通过对浮游生物分馏样品进行化学分析，得到以下信息。1. 一般情况下，苏华乳酸菌样品的氮碳比和磷碳比高于奥玉乳酸菌样品。这两个比值在浮游动物中高于浮游植物；N/C为2倍，P/C为4倍，表明放牧活动中元素凝结的必要性。3. 测定细菌细胞中C、N的含量；细胞体积0.06 ~ 0.19 pgC/um，平均N/C比0.203。一项利用H胸苷吸收的实验表明，磷是寡营养湖泊中细菌生产的限制营养物。浮游植物的生长和元素组成受食物浮游植物氮、磷含量的影响，特别是在低食物浓度下。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起营养物质再生的作用。

项目成果

清沢弘志: 日本陸水学会誌.

清泽浩：日本湖沼学会杂志。

WATANABE,YASUNORI.: Marine Microbial Food Webs. 4. (1989)

WATANABE,YASUNORI.：海洋微生物食物网。

KIYOSAWA, HIROSI: "Seasonal change of phytoplankton and its growth limiting nutrient in Lake Kizaki, Japan" Jpn. J. Limnol.

HIROSI KIYOSAWA：“日本木崎湖浮游植物的季节变化及其生长限制营养物质”Jpn。

WATANABE, YASUNORI: "Effect of cellular carbohydrate content and nutrient status on the respiratory oxygen uptake of a Microcystis population in a eytrophic pond" Marine Microbial Food Webs.4. (1989)

WATANABE、YASUNORI：“细胞碳水化合物含量和营养状态对营养池塘中微囊藻种群呼吸吸氧量的影响”海洋微生物食物网。4。

WATANABE,YASUNORI: Marine Microbial Food Webs.4. (1989)

WATANABE，YASUNORI：海洋微生物食物网.4。