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Dynamics of organic colloidal particles in aquatic microbial food webs

水生微生物食物网中有机胶体颗粒的动力学

基本信息

批准号：
07404044
负责人：
KOIKE Isao
金额：
$ 11.65万
依托单位：
Ocean Research Institute, University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

项目摘要

The aim of this research is the mechanistic understanding of organic detritus dynamics in marine environments through focusing on the characterization of submicron sized detritus and their production and degradation by microbial food webs such as bacterioplankton and microzooplankton. The finding of" submicron particles " as the predominant forms of non-living organic detritus of bacterial size range in 1990 by our group stimulated the studies on the role of those organic detritus, which are in the boundary between dissolved and suspended forms of detritus in the upper ocean. Before this research, however, a few knowledge has been obtained in the open ocean, such as size distribution and some physico-chemical properties, partially because of the limit of available techniques. Through the interdisciplinary approaches of this study, following new findings were obtained. 1. The size distribution of submicron organic detritus varied significantly with the biological productivity of the env … More ironments, and the production of 0.6-0.8 mum sized detritus dominated under the high biological productivity. 2. Estimated carbon contents of organic detritus of submicron size range gave much higher value compared to the carbon contents of living particles of this size, i.e., bacteria, indicating that organic detritus of submicron size are also predominant form of organic carbon stock in the upper ocean. 3. Using a high sensitivity CCD camera system, amorphous and aggregated nature of those organic detrital particles were confirmed, This finding was consistent with the previous physical characterization of the particles. 4. As the major production process of the submicron detritus, fecal pellets formation of microflagellates through the grazing activities were strongly suggested, and also further aggregation of those submicron detritus to larger sized aggregates were indicated, The above findings were the important contribution to mechanistic understanding of complicated dynamics of marine organic detritus, such as marine snow, suspended-, colloidal- and dissolved-organic forms, and their association with marine food webs. Less

本研究的目的是通过关注亚微米级碎屑的特征及其在浮游细菌和微型浮游动物等微生物食物网中的产生和降解，来了解海洋环境中有机碎屑动力学的机制。1990年本组发现以“亚微米颗粒”为细菌大小的无生命有机碎屑的主要形态，激发了对这些有机碎屑作用的研究，这些有机碎屑处于海洋上层溶解和悬浮碎屑的边界上。然而，在进行这项研究之前，由于现有技术的限制，人们对开放海洋的大小分布和一些物理化学性质知之甚少。通过本研究的跨学科方法，获得了以下新发现。1. 亚微米级有机碎屑的大小分布随环境的生物生产力变化显著，高生物生产力环境下以0.6 ~ 0.8微米级有机碎屑为主。2. 亚微米级有机碎屑的碳含量估算值远高于该尺寸的活颗粒（即细菌）的碳含量，表明亚微米级有机碎屑也是上层海洋有机碳储量的主要形式。3. 利用高灵敏度CCD摄像系统，证实了有机碎屑颗粒的无定形和聚集性质，这一发现与先前颗粒的物理表征相一致。4. 研究结果表明，微鞭毛虫在放牧过程中形成粪球是亚微米碎屑的主要产生过程，并且这些亚微米碎屑还会进一步聚集成更大的聚集体。这些发现对理解海洋有机碎屑的复杂动态机制有重要贡献，如海洋雪、悬浮有机、胶体有机和溶解有机形式。以及它们与海洋食物网的联系。少