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：
03041027
负责人：
KOIKE Isao
金额：
$ 10.88万
依托单位：
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：
1991
资助国家：
日本
起止时间：
1991 至 1993
项目状态：
已结题

项目摘要

During the spring season in 1991 and 1992, we sent scientific party to Dravuni Island, Fiji, to investigate the biological structure and clcling of bioelements in tropical seagrass bed ecosystem.In 1991, the participants were mostly biologists doing the field observation of seagrass biomass, their growth, transfer of produced organic materials to secondary producers, benthic as well as epiphytes, and fine biological structures of those communities. In 1992, environmental and experimental studies on metabolic rates of dominated animals were carried out. Following are the main results of 1991-1992 field studies.(1)Averaged turnover time of above the ground part of dominated seagrass, i.c., Syringodium, was estimated to be ca. 1 month, while that of underground part, rhizome, was more than 500 days. We also obtained similar result from Thalassia in Papua New Guinea, and large standing stock of underground part of seagrass and slow turnover time is rather common characters of tropical seagrass, reflecting nutrient poor outer environments.(2)For the supply of nitrogen, nitrogen fixation by benthic communities as well as epiphytes seems to be significant contribution to the total nitrogen budget of the system. In Papuan seagrass bed, which is near the continent, contribution of nitrogen fixations ca. 10 % of nitrogen demand by seagrass population. But, in Fiji as an nutrient poor ocean island, nitrogen fixation accounted upto several 10% of community nitrogen demand.(3)For the decomposition of seagrass, there was not so many direct grazers and major population of heterotrophic animals were filter feeders, including bivalves and compound ascidians., indicating the importance of suspended organic materials as the food. On the other hand, bacterial activities at the interface of sediment-water column were high, suggesting the importance of their processes on decomposition of the dead seagrass.

在1991年和1992年的春季期间，我们派遣科学党去了斐济的德拉沃岛，调查了热带海草床生态系统中生物元素的生物结构和clcling。社区。 1992年，对主导动物的代谢率进行了环境和实验研究。以下是1991 - 1992年现场研究的主要结果。（1）据估计，平均的营业额在地面上方的地面部分，I.C.，syringodium估计为CA。 1个月，而地下部分的根茎是超过500天。我们还获得了巴布亚新几内亚丘脑的相似结果，海草的地下一部分和缓慢的转移时间的大量库存是热带海草的相当常见特征，反映了营养不良的外部环境。（2）氮，脑静脉固定的氮固定量和预算是大量贡献的氮，氮固定的含量是重要的。在大陆附近的巴布亚海草床中，氮固定的贡献。海草种群的氮需求的10％。但是，在斐济，作为一种营养贫穷的海洋岛，氮固定占社区氮需求的10％。（3）对于海草的分解，没有太多的直接放牧者和主要的异育动物种群是滤液饲养者，包括双壳类和化合物效果，表明了食品的重要性。另一方面，沉积物 - 水柱界面处的细菌活性很高，这表明其过程对死海草分解的重要性。