Developmental Process and Material Flow in Tropical Seagrass Beds

热带海草床的发育过程和物质流

基本信息

批准号：
01041027
负责人：
KOIKE Isao
金额：
$ 5.76万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01041027/
关键词：
Seagrass bed ecosystem Primary production Nitrogen metabolism Filter feeders Symbiosis Epiphytes Benthos Herbivorous fish

项目摘要

It has been clarified by previous studies that tropical seagrass ecosystem has several food-chains consisting by high diversity of seagrasses and benthic animals in Papua New Guinean seagrass bed, which locates in center of seagrass distribution. Otherwhile, in marginal Fijian seagrass beds, there was pure stands of Syringodium isoetifolium.1. Concentration of nutrients in ambient seawater and within seagrass vegetation was very low, while it in interstitial water of seagrass bed sediment was 10-100 times of ambient seawater. It is originated from decomposition of detritus accumulated in sediments. Organic carbon and nitrogen in sediment of bare bottom did not change from bottom surface to 20 cm deep, and the C/N ratio was ca.10 (g/g). While, organic carbon in seagrass bed sediment reduced to 1/3 at 20 cm deep, but organic nitrogen did not change unlikely in carbon. This suggests that nitrogen has never been lost in bacterial metabolism and is effectively taken up again by seagrasses.2 … More . Biomass and primary production of Syringodium pure stand were measured by (1) marking method, (2) oxygen evolution measurement, (3) lacuna gas volumetry. The production rates were 2.5-11.2 g/m2/day. This range of primary production was not low compared with high diversity seagrass beds in Papua New Guinea, because of very dense stand in Syringodium stand.3. Characteristics of Fijian seagrass bed are in abundant filter feeding benthic animals, in spite of poverty in phytoplankton. Among the animals, bivalves can be sustained themselves by a mechanism in which detritus from seagrass and epiphytes is accumulated in high concentration within dense seagrass stands. Otherwhile, compound ascidians attached to seagrass leaf, having abundant biomass (ave. 14.8 g/m2), contribute also to primary production, because of symbiosis with algae. It was estimated by our experiments that the ascidians obtained half and half of nutrients from CO2 fixation by symbiotic algae and subordinate nutrition by filter feeding. In nitrogen metabolism, independent nutrition was effective. Less

先前的研究已经阐明了热带海草生态系统拥有几种食品链，其中包括新几内亚海草床的高多样性海草和底栖动物，该床位于海草分布中心。另外，在边缘的斐济海草床中，有纯种同叶的纯林。1。环境海水和海草蔬菜中的养分浓度非常低，而在海草床沉积物的间隙水中则是环境海水的10-100倍。它最初来自沉积物中积累的碎屑的分解。裸露底部沉积物中的有机碳和氮没有从底部表面变为20厘米深，C/N比为CA.10（g/g）。而在20厘米深的海草床沉积物中的有机碳降低至1/3，但有机氮在碳中的变化不大。这表明，氮在细菌代谢中从未丢失，并且被海草有效地吸收。2…更多。通过（1）标记方法，（2）氧气进化测量，（3）lacuna气体体积测量生物量和原发性生产。生产率为2.5-11.2 g/m2/天。与巴布亚新几内亚的高多样性海草床相比，这一范围的初级生产范围并不低，因为在三体林中非常密集。3。斐济海草床的特征是在浮游植物的绝对过滤中喂养底栖动物。在动物中，双壳类动物可以通过一种机制来维持，在这种机制中，海草和附生植物的碎屑在密集的海草林中积累了高浓度。其他同时，由于与藻类的共生性，由于具有丰富生物量的海草叶（大街14.8 g/m2）附着于海草叶（大街14.8 g/m2）。通过我们的实验估计，海囊虫通过共生藻类从二氧化碳固定中获得了一半和一半的营养，并通过过滤器喂养从下属营养获得了营养。在氮代谢中，独立营养是有效的。较少的