【作者】 魏建伟；

【导师】 石学法；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 海洋地质学， 2005， 博士

【摘要】 论文以2004年在西菲律宾海获取的光学剖面资料为基础,首次将光学衰减系数作为悬浮有机颗粒的替代指标,对西菲律宾海上层水体悬浮颗粒及颗粒有机碳的时空分布和变化进行了研究。结果表明,光衰减系数c_p同颗粒有机碳浓度具有显著的线性相关关系,这对于海洋初级生产力估算和碳循环研究具有重要意义。断面WE和SN上的浮游植物现存量与颗粒有机碳现存量变化趋势完全一致。上层水体中的颗粒有机碳主要来源于有机碎屑颗粒。西菲律宾海混合层的昼夜变化对于表层水体光学变异以及颗粒输出作用具有重要影响。表层水温、光衰减系数c_p和混合水深都与海面光合有效辐射同相变化。表层水体中的颗粒有机碳现存量同混合水深同步变化,受混合层控制作用显著;而对于深层水体,推测主要受生物垂向迁移和颗粒聚集沉降的影响。根据表层水体中微微型自养颗粒的计数分析结果,原绿球藻的丰度最高,其次为聚球藻,自养真核细胞的丰度最低。首次估算了三种微微型颗粒的散射系数,并与光衰减系数c_p做了对比分析。研究表明,菲律宾海三种微微型颗粒的散射作用仅占光衰减系数c_p的5%,其中原绿球藻、自养真核细胞和聚球藻分别占2.17%、2.85%和0.33%。根据微微型颗粒的散射特征,可大致将研究海区划分为三个生物水文学区域。对菲律宾海上层水体的光场特征作了分析,结果表明水下辐照度Ed按照指数规律衰减。通过对漫衰减系数Kd的研究,首次证实了西菲律宾海非藻组分的光衰减作用占主要地位。表层水体中非藻组分与浮游植物的光衰减作用大小相近,随着水深增大,非藻组分的光衰减作用逐渐占据主导地位。此外,西菲律宾海离水辐亮度Lwn(555)和海面遥感反射率Rsr(555)同生物地球化学核心变量POC之间存在显著的指数相关关系,这对于海洋初级生产力的遥感估算和应用具有重要意义。更多还原

【Abstract】 A new proxy of particulate organic material was optically determined in West Philippine Sea, and the optical data was firstly used to examine the suspended particle and POC variability. Using these linear fit equations between beam attenuation coefficients at 660nm (c_p) and POC, continuous and high-resolution POC profiles could be derived. Integrations of POC and chlorophyll a to 150m within transect of WE and SN revealed uniform spatial variations than expected, and POC in the upper water column mainly came from the detrital particulate materials. In West Philippine Sea, the diel changes of mixed layer depth played a significant role in the optical variability and particle export of the upper layer. The sea surface temperature, beam attenuation coefficient due to particles and the mixed layer depth covary with the photosynthetically available radiation (PAR). The standing stocks of POC in the surface waters were controlled by the changes of mixed layer depth. But in the mid- and lower water column, it was speculated that vertical migration, aggregation and sinking contributed to the POC standing stock.The numerical abundances of three microorganisms (Prochlorococcus, Synechococcus and autotrophic eukaryotes) and their optical scattering cross sections were determined. The bulk scattering coefficients of each population (bp) and total scattering coefficients of these three picoplankton populations (bp(Tot)) were calculated and compared with beam c_p. In West Philippine Sea, Prochlorococcus was the most abundant population, and the abundance of autotrophic eukaryotes was the lowest. The autotrophic eukaryotes and Prochlorococcus were the most significant contributors to the beam c_p (2.85% and 2.15% of beam c_p, respectively) via scattering, and only 0.33% of the beam c_p was accounted for by Synechococcus. And the study area could be subdivided into three biohydrographic regimes according to particle scattering.The underwater light field was also observed in the West Philippine Sea, and it更多还原