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Study on the function of carbon transport by heterotrophic dinoflagellates

异养甲藻碳运输功能的研究

基本信息

批准号：
17310016
负责人：
SAITO Hiroaki
金额：
$ 8.38万
依托单位：
Fisheries Research Agency
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17310016/
关键词：
heterotrophic dinoflagellate diatom faecal pellet carbon cycling biological pump plankton subarctic

项目摘要

Diatoms play an important role jn the carbon sequestration to the deep sea, i.e., biological pump. The fate of diatom bloom is largely influenced by the cell sinking, sinking as faecal pellet of diatom grazer, or remineralization in the epipelagic layer. In order to understand the fate, many studies on the macrozooplankton feeding on diatoms has been carried out. On the other hand, biology and ecology of the other diatom feeder, heterotrophic dinoflagellates, are limited, and the role of the dinoflagellates on carbon sequestration is unknown. In this study, we investigated on the diatom grazing by dinoflagellates and the role on carbon sequestration.We found 4 diatom-feeding heterotrophic dinoflagellates, such as Gyrodinium sp. , in the genus of Gyrodinium and Gymnodinium in the subarctic Pacific. Their contribution in microzooplankton assemblage is generally low. , and often absent. The high biomass was observed in the diatom blooming station. The contribution of the heterotrophic din … More oflagellates reached 20% of total microzooplankton in number in the Oyashio region and 60% in the carbon biomass. In the central region of the western subarctic gyre, their contribution was 10% in weight at the non-bloom status, and it increased to 50%(20.1 mgC m^<-3>) during the bloom. These indicate that the dynamics of the heterotrophic dinoflagellates is largely dependent on the diatom density. The maximum ingestion rate observed was 532 mgC m^<-3> d^<-1>.The mathematical simulation showed that the heterotrophic dinoflagellates had potential to graze down all the diatom production during diatom bloom in the western subarctic Gyre. The importance of the grazing on the carbon transport is largely influenced by the initial cell density of the dinoflagellate and the predator density. In the case of the low initial density of the dinoflagellates or high predator density, the biomass of the dinoflagellates does not reach to high enough to impact the diatom bloom within the general duration of the event of 1-4 weeks It is suggested that the selective feeding of copepods on the dinoflagellates decrease the population size when the timing of copepod growth period initiate earlier than the diatom bloom. These results indicate that the diatom, carbon and nutrient dynamics in spring are crucially influenced by the food-web components.This study demonstrate the ecological characteristics of the heterotrophic dinoflagellates and their influence of carbon and biogenic elemental cycling which are little know previously. It is, however, still unclear the roles on the food-web dynamics and biogeochemical cycling due to their large horizontal and temporal variations in their abundance. We need further studies on physiological and biological characteristics of the heterotrophic dinoflagellates in order to develop the ecosystem model including the dinoflagellate and to understand their role in the ecosystem and biogeochemical cycling. Less

硅藻在深海固碳即生物泵中起着重要作用。硅藻华的命运在很大程度上受细胞下沉、作为硅藻食草动物的粪便颗粒下沉或上层层再矿化的影响。为了了解硅藻的命运，人们对以硅藻为食的大型浮游动物进行了许多研究。另一方面，另一种硅藻食料异养鞭毛藻的生物学和生态学是有限的，鞭毛藻在固碳中的作用是未知的。本研究探讨了鞭毛藻对硅藻的掠食及其在固碳中的作用。在亚北极太平洋地区发现了4种以硅藻为食的异养鞭毛藻，如Gyrodinium sp.。它们在微型浮游动物组合中的贡献通常很低。，而且经常缺席。硅藻开花站的生物量较高。异养型甲藻对小浮游动物总数的贡献达到20%，对碳生物量的贡献达到60%。在亚北极西部环流中部地区，它们在非水华状态下的贡献为10%，在水华状态下增加到50%（20.1 mgC m^<-3>）。这表明异养鞭毛藻的动态在很大程度上取决于硅藻密度。观察到的最大摄食率为532 mg - gc m^<-3> d^<-1>。数学模拟表明，异养鞭毛藻有可能在亚北极西部环流硅藻华期间吃掉所有的硅藻产量。放牧对碳转运的重要性在很大程度上受鞭毛藻初始细胞密度和捕食者密度的影响。在甲藻初始密度较低或捕食者密度较高的情况下，甲藻生物量在1 ~ 4周的事件总持续时间内不足以影响硅藻华的发生。提示，当桡足类生长期开始时间早于硅藻华时，桡足类对甲藻的选择性取食减少了种群规模。这些结果表明，春季硅藻、碳和养分动态受到食物网成分的重要影响。本研究揭示了异养鞭毛藻的生态特性及其对碳和生物源元素循环的影响。然而，由于其丰度的巨大水平和时间变化，其在食物网动态和生物地球化学循环中的作用尚不清楚。为了建立包括异养鞭毛藻在内的生态系统模型，了解其在生态系统和生物地球化学循环中的作用，需要进一步研究异养鞭毛藻的生理生物学特性。少

项目成果

期刊论文数量（0）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

The roles of ecosystem components for biogeochemical cycling in the HNLC subarctic Pacific

HNLC 亚北极太平洋生态系统组成部分对生物地球化学循环的作用

DOI：
发表时间：
2008
期刊：
影响因子：
0
作者：
Saito;et. al.
通讯作者：
et. al.

Meso-and microzooplankton responses in the iron-enrichment experiments in the subarctic North Pacific(SEEDS,SERIES,SEEDS-II)

北太平洋亚北极铁富集实验中中观和微型浮游动物的反应(SEEDS,SERIES,SEEDS-II)

DOI：
发表时间：
2006
期刊：
影响因子：
0
作者：
Tsuda;et. al.
通讯作者：
et. al.

A review of solubility and dissolution rates of biogenic silica : Present and future direction

生物二氧化硅的溶解度和溶解速率综述：现在和未来的方向

DOI：
发表时间：
2007
期刊：
Oceanography in Japan 16
影响因子：
0
作者：
Kamatani;A.;S. Takeda
通讯作者：
S. Takeda

Effect of iron enrichment on the dynamics of transparent exopolymer particles in the western subarctic Pacific

DOI：
10.1016/j.pocean.2005.02.012
发表时间：
2005-02
期刊：
Progress in Oceanography
影响因子：
4.1
作者：
N. Ramaiah;S. Takeda;K. Furuya;T. Yoshimura;J. Nishioka;T. Aono;Y. Nojiri;K. Imai;I. Kudo;H. Saito;A. Tsuda
通讯作者：
N. Ramaiah;S. Takeda;K. Furuya;T. Yoshimura;J. Nishioka;T. Aono;Y. Nojiri;K. Imai;I. Kudo;H. Saito;A. Tsuda

Turbulence and feeding behaviour affect the vertical distributions of Oithona similis and Microsetella norwegica