Re-evaluation of dissolved organic matter (DOM) in detritus food web

碎屑食物网中溶解有机物（DOM）的重新评估

• 批准号: 16510003
• 负责人: SATOH Yasuhiro
• 金额: $ 1.15万
• 依托单位: Yamagata University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16510003/
• 关键词: dissolved organic matter; Fe(III) precipitates; coprecipitation; availability of DOM; anoxic hypolimnion; aeration experiment; microbial loop; re-evaluation; 湖沼; 嫌気層; 曝気実験; 鉄の酸化還元; 溶存有機物の共沈; Dissolved organic matter; 微生物可使性; 鉄、マンガン

Dissolved organic matter (DOM) dominates over organic matter pool in lakes. Until 1980s, DOM was thought to be waste and useless substances in the energy flow in the lakes. However, the importance of DOM was re-evaluated. Azam et al. (1983) named "microbial loop" in which bacteria used DOM to build up their body, protozoa ate bacteria, and then zooplankton ate protozoa. Thus energy flow of microbial loop stems from DOM.On the other hand, hypolimnion of a productive lake becomes anoxic in summer, because of bacterial decomposition of organic matter from productive photosynthetic layer. Fe(III) and Mn(IV) in the lake sediment are reduced to Fe(II) and Mn(II), respectively and dissolved into hypolimnetic water. On the autumnal water circulation, these dissolved metals are oxidized to Fe(III) and Mn(IV) and the solubility of these compounds are small, resulting in the precipitation. Fe(III) precipitates coprecipitate many inorganic and organic compounds. Some DOM in natural lake water shou … More ld be coprecipitated by Fe(III) precipitates. However, no information is available on this phenomenon.The present study revealed that when hypolimnetic anoxic water from Lake Hibara agitated by a magnetic stirrer for 24 hr, dissolved oxygen (DO) increased from 0 to 7.6 mgl^<-1>, Fe(II) decreased from 98% of the total Fe to 5% and simultaneously massive yellow precipitate formed, and 32-48% DOC disappeared. When the water sample left unstirred for 48 hr, DO increased to 2.2 mgl-1, Fe(II) decreased to 31%, and 20% of DOC disappeared. The amount of disappeared DOC is too large to explain bacterial decomposition. The yellow precipitates should be Fe(III) precipitates and these precipitates must coprecipitated disappeared DOC.The mixing experiments of hypolimnetic anoxic water with aerobic surface water to simulate autumnal water circulation of a lake were conducted in this year. Duplicate incubations were carried out. The results likely suggested the coprecipitation. However, precision of the incubations were not enough to predict the difference between controls and treated samples. Methodological improvement is desired in the nest step. Less

溶解的有机物（DOM）在湖泊中的有机物库中占主导地位。直到1980年代，DOM被认为是湖泊能量流中的浪费和无用的物质。但是，重新评估了DOM的重要性。 Azam等。 （1983年）称为“微生物环”，其中细菌使用DOM积累了身体，原生动物吃了细菌，然后在原生动物的浮游动物。微生物环的能量流程从另一方面，由于生产性光合层的细菌分解有机物的细菌分解，因此夏季，生产湖的降压在夏季变得缺氧。湖泊沉积物中的Fe（III）和Mn（IV）分别还原为Fe（II）和Mn（II），并溶解在迟发水中。在秋天的水循环中，这些溶解的金属被氧化为Fe（III）和Mn（IV），这些化合物的溶解度很小，导致沉淀。 Fe（III）沉淀共沉淀许多无机和有机化合物。自然湖水中的一些人……更多的LD由Fe（III）沉淀。然而，目前的研究表明，当磁性搅拌器搅动24小时的低颗粒性缺氧水24小时时，溶解的氧气（DO）从0增加到7.6 mgl^<-1>>>>>>>>，Fe（II）从fe的98％降低到5％的98％降至5％和大量的黄色降水量和322-222-22-22222222。当水样不稳定48小时时，DO升高到2.2 mgl-1，Fe（II）降至31％，而DOC的20％消失了。消失的DOC的数量太大，无法解释细菌分解。黄色的沉淀物应为Fe（III）沉淀，这些沉淀必须消失的DOC。次氧化无毒水与有氧地表水的混合实验模拟了湖泊的秋季循环。进行了重复的孵化。结果可能表明了共沉淀。但是，孵育的精度不足以预测对照和处理样品之间的差异。在巢步中需要方法学改进。较少的

项目成果

Potential capacity of coprecipitation of dissolved organic carbon (DOC) with iron(III) precipitates

• DOI: 10.1007/s10201-006-0184-y
• 发表时间: 2006-10
• 期刊: Limnology
• 影响因子: 1.6
• 作者: Y. Satoh;Keiko Kikuchi;S. Kinoshita;H. Sasaki