Study on interaction of marine snow dynamics and biological processes within the vicinity of the pycnocline of upper ocean.

上层海洋密斜层附近海洋雪动力学与生物过程相互作用的研究。

基本信息

批准号：
16370010
负责人：
KOIKE Isao
金额：
$ 6.91万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
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

项目摘要

Although marine snow plays important role on the transport of organic carbon produced at the upper ocean into the ocean interior, its biogeochemical studies have been restricted to the coastal area, because of the access problems. In this study, we focused on the interaction of biological processes and physical environments in the vicinity of upper layer, to understand the production and vertical transfer of marine snow by using newly developed marine-snow camera. In FY2004, improvements of the camera systems and their performance test have been conducted, i.e., use of new LED light source and addition of clear sight and others. Main field campaign was performed during the Hakuho-Maru Cruise (July-September, 2005) to the central Pacific transect (10°S - 53°N, 160°W), which includes from oligotrophic region to rather nutrients rich sub-arctic region. In this long transect, no survey has been done before using marine snow camera. Followings are major results obtained from the field studies. (1) Presence of peak of marine snow abundance was confirmed at the pycnocline of the nutrients rich sub-arctic area. (2) Integrated amounts of chlorophyll a at the 0-200m depth along the transect showed about 2.5 fold difference, while the same treatments of marine snow volume gave about 50 times difference. This comparison suggests that several factors including physical environments, size of phytoplankton, and food web structures in this transect control abundance of marine snow in the upper layers. (3) The depth of pycnocline located between 30-110m depths in the study areas. The ratio of integrated chlorophyll a amounts between 0-100m and 100-200m depths along the transect showed a good correlation with the ratio of marine snow volume obtained by the same treatment. Since primary source of marine snow (>0.5mm size) is phytoplankton of 0.8-100 micron size, aggregation processes to produce marine snow may occur without any large vertical movement of these source materials.

尽管海洋雪在上海内部生产的有机碳的运输中起着重要作用，但由于通道问题，其生物地球化学研究被限制在沿海地区。在这项研究中，我们专注于上层附近生物过程和物理环境的相互作用，以使用新开发的船用抢断摄像头了解海洋雪的生产和垂直转移。在2004财年，已经进行了相机系统及其性能测试的改进，即使用新的LED光源以及添加清晰的视力等。在Hakuho-Maru Cruise（2005年7月至9月）向中太平洋样带（10°S-53°N，160°W）进行了主要野外运动，其中包括从贫营养区域到较为营养的富含营养的亚北极地区。在这个长的横断面中，在使用海洋雪摄像头之前没有进行调查。以下是从现场研究获得的主要结果。（1）在富含亚北极亚北极地区的pycNocine上证实了海洋积雪的峰值。（2）沿着所示的横断面的0-200m深度的融合量叶绿素A大约2.5倍的差异，而相同的海洋积雪处理方法的差异约为50倍。这种比较表明，在这种横层中海洋积雪的横向控制抽象中，包括物理环境，浮游植物的大小以及食物网络结构在内的几个因素。（3）在研究区域中位于30-111M深度之间的pycnocline的深度。沿横切的0-100m至100-200m深度之间的综合叶绿素的比率与通过相同处理获得的海洋雪体积的比率有良好的相关性。由于海洋积雪的主要来源（> 0.5mm尺寸）是浮游植物的0.8-100微米尺寸，因此在没有这些原始材料的任何垂直垂直运动的情况下，可能会发生聚集过程以产生海洋积雪。