【作者】 郝锵；

【导师】 宁修仁； 唐学玺；

【作者基本信息】 中国海洋大学 ， 生态学， 2010， 博士

【摘要】 研究通过实测和遥感反演两方面的相结合,研究中国近海浮游植物生物量和初级生产力的时空变化和环境调控机制,描述不同海域叶绿素和生产力的季节和年际变化特征,探讨其生态动力学过程,并尝试估算中国近海浮游植物固碳量。首先通过对近三十年来叶绿素和初级生产力资料的整理和分析,研究了黄、东海大尺度浮游植物生物量和初级生产力的区域分布特征。通过对浮游植物生物量和初级生产力的相关参数进行聚类分析结果表明,浮游植物生物量和初级生产力的分布存在明显的区域特征和季节变化,其特征区的边界和各参数的水平与所在海域水团的性质、时空变化以及水深密切相关,其中高营养盐浓度、低真光层厚度的沿岸水与低营养盐浓度、高真光层厚度的黑潮水相互消长与混合是这一系列变化的主要驱动过程。研究同时表明黄、东海浮游植物分布能够反映不同生境的特征,以浮游植物的分布特征进行生态区划是可行的。在南海,通过2004年2月所进行的多学科综合调查,研究了该海域冬季浮游植物生物量和初级生产力的分布、粒级组成及其环境调控机制。结果表明南海北部叶绿素浓度平均为0.6mg/m3,初级生产力为386 mgC/m2/d。浮游植物生物量和初级生产力及其粒度结构主要受环流驱动下的营养盐调控,研究海域存在明显的物理一生物海洋学耦合过程。在近岸海域,受沿岸流和珠江冲淡水的影响呈现出低温、低盐、高营养盐、高叶绿素和初级生产力的特征；而在陆架以外区域营养盐和浮游植物的分布主要受中尺度涡控制,其中反气旋涡区以高温、低盐、低营养盐、低叶绿素和低初级生产力为主要特征,而在气旋涡区的特征则与之相反。浮游植物粒度结构沿岸带为小型(Net)>微型(Nano)>微微型(Pico),陆架以外海域大体为Pico>Nano>Net; Net、Nano和Pico级浮游植物对海域生物量和初级生产力的贡献分别为24.16%,30.36%、45.48%和11.81%、25.35%、61.84%。其次,在对国际主流初级生产力模型比较的基础上,基于渤、黄、东海的浮游植物群落特征,建立一个改进型的初级生产力反演模型(C-VGPM)。利用SeaWiFS提供的Chl a、K490、PAR等遥感产品计算得到了模式所需的各项参数,通过模型计算得到了渤、黄、东海10年(1998～2007)来叶绿素和初级生产力的分布资料。结果显示研究海域的初级生产力的季节分布为单峰形式,具体为夏季(524 mgC/m2/d)>春季(424 mgC/m2/d1>秋季(346 mgC/m2/d)>冬季(177 mgC/m2/d)；各海域中黄海最高(404 mgC/m2/d),东海次之(372 mgCm2/d),渤海最低(289 mgC/m2/d,全海域平均为368 mgC/m2/d.陆架和河口海域是东中国海浮游植物生物量和生产力最高的区域,沿岸带和陆架外海域则相对较低。研究对近海叶绿素和初级生产力的时空变化给出了更为细致的描述,发现就全局而言,东中国海的“气候-水团-陆源输入”共同控制着浮游植物生物量和生产力的水平和分布。在南海海域,选取VGPM模式对南海北部海域初级生产力进行反演,,结合现场实测数据对模式进行了修订和误差分析。在此基础上通过反演计算获得了南海北部海域七年平均(1998～2004)初级生产力逐月分布图像。研究结果表明,研究海域初级生产力分布趋势为由沿岸带向陆架以及外海逐渐降低,其中沿岸带区高于400mgC·m-2·d-1,外海区大致在100～300 mgC·m-2·d-1;初级生产力水平冬季最高(平均为608 mgC·m-2·d-1)、夏季最低(平均为292 mgC·m-2·d-1),春、秋季基本持平。控制初级生产力时空分布的因子主要有营养盐、温度、光照,其中又以季风和环流驱动下的营养盐变化对初级生产力的调控最为显著。通过计算南海河口、上升流及反气旋涡等生境表层叶绿素和初级生产力的周年变化,进一步分析南海北部不同生境的物理-生物海洋学耦合特征。结果表明,季风驱动下的物理—化学—生物海洋学耦合过程是控制研究南海浮游植物生物量和初级生产力时空变化的主导因素。浮游植物生物量和初级生产力随着季风、环流以及中尺度涡等物理现象的更替而呈现出明显的区域差异和季节变化；其高值一般出现在珠江口和沿岸上升流区,而低值则出现在外陆架反气旋涡和海域南端,往往伴随东北季风的盛行而升高,随西南季风的增强而降低。通过遥感资料估算得到南海北部海域浮游植物年固碳量为4.83×107t C,其中沿岸带、陆架、开阔海海域对整个研究海域固碳量的贡献分别为38%、29%和33%。更多还原

【Abstract】 In this dissertation, spatial and temporal distributions of phytoplankton biomass and primary products in Chinese coastal area, and its environmental control mechanism are studied by combining the approaches of both on site measurement and modeling based on ocean remote sensing data. The seasonal and annual variations of chlorophyll and primary production in different sea areas are described, and the corresponding eco-dynamic process is discussed. In addition, the quantity of carbon fixed by phytoplankton in Chinese coastal area is estimated.Large-scale ecological zonation of the Yellow Sea (YS) and East China Sea (ECS) were studied through sorting out and analysis of chlorophyll a and primary production data for nearly 30 years. The studied sea areas were partitioned into several ecological zones by cluster analysis of correlative parameters of phytoplankton biomass and production. Distribution of biomass and production of phytoplankton exhibited obvious regional characteristics and seasonal variation; their border and levels in the ecological zones were closely related to water masses’ properties, and the temporal and spatial variations.In it, the mutual growth and decline and mixing between the coastal water with high nutrient concentration and thin euphotic zone, and Kuroshio water with low nutrient concentration and thick euphotic zone were main factors governing the processes of a series of ecological variation.The research results also showed that although the partitioning results exhibited seasonal and spatial variations, three ecological zones, i.e. the Coastal Zone, Kuroshio Zone and East China Sea Shelf Zone were fundamental zones reflected pronouncedly by major temporal and spatial patterns of phytoplankton biomass and production in the Yellow Sea and East China Sea.In this paper, the distributions, size fractionations and environmental control mechanisms of phytoplankton stock and primary production (PP) in the northern South China Sea were studies based on a comprehensive survey conducted in February 2004 in this area.The results show that the average concentrations of chlorophyll a (Chla) is 0.6 mg/m3 and PP is 386 mgC/m2/d.The distributions and size fractionations of Chla and PP in the northern South China Sea (NSCS) are mainly controlled by the nutrients which driven by monsoon-circulation and there are obvious coupled physical-chemical-biological processes in this area.In detail, in the coastal zone, influenced by the coastal current and Zhujiang dilute water, the characteristics are low temperature, low salinity, rich nutrients, high Chla and PP. While in the deep sea, the distributions of nutrients and Chla are mainly controlled by the mesoscale eddies:high temperature, low salinity, poor nutrients, low Chla and PP appear when controlled by the anticyclonic eddies and the characteristics are on the contrary when controlled by cyclonic eddies. With respect to the size fractionations of phytoplankton, Net>Nano>Pico are observed in the coastal zone, while Pico>Nano>Net in deep sea. The contributions of Net, Nano and Pico for Chla and PP are 24.16%,30.36%,45.48% and 11.81%,25.35%, 61.84%, respectively in the whole study area.In this study, an enhanced primary production estimation model (C-VGPM), which is more suitable for Chinese costal area, has been established based on comparing mainstream international primary production estimation models and analyzing the characteristics of phytoplankton community in Bohai Sea, Yellow Sea and East China Sea. The model parameters are calculated from remote sensing products, such as Chl a、K490 and PAR et al.,provided by the satellite SeaWiFS.By using the C-VGPM model and appropriate model parameters, the distributions of chlorophyll and primary production in ten years, from 1998 to 2007, are estimated.The results show that the seasonal distribution of primary production in the studied sea area is a single peak. The primary production in summer is the highest, i.e.,PP in summer (524 mgC/m2/d)>PP in spring (424 mgC/m2/d)> PP in autumn (346 mgC/m2/d)> PP in winter(177 mgC/m2/d). In terms of spatial distribution, PP in Yellow Sea is the highest (404 mgC/m2/d), the middle is in the East China Sea(372 mgC/m2/d), the lowest is in Bohai Sea (289mgC/m2/d).The average primary production in the whole studied sea area is 368 mgC/m2/d.The highest phytoplankton biomass and primary production in China Sea appears in shelf and estuary area, while those in the costal area and off-shelf area are comparatively lower. The spatial and temporal distributions of inshore chlorophyll and primary production are described in detail in this study. It is observed that from an overall point of view, the climate, the water mass and the terrestrial input in China Sea control the quantity and distribution of phytoplankton biomass and primary production together. An improved VGPM model were developed and applied to estimate the primary production in the northern South China Sea. The parameters of the model were gained based on the remote sensing data(including Chl a,K490 and SST et al.)provided by SeaWiFS and AVHRR.The model was modified according to the synchronous ship-measured data and the errors were estimated as well.Based on this improved model, the monthly mean of primary production in 7 years(1998 to 2004) in the northern South China Sea were calculated.Results show that the primary production in the studied area gradually decrease from coastal zone (the mean >400 mgC·m-2·d-1) to deep sea (100～200 mgC·m-2·d-1).With respect to the seasonal variation, the daily average primary production in the whole study area is the highest in winter (608 mgC·m-2·d-1) and the lowest in summer (292 mgC·m-2·d-1) and it is almost the same between spring and autumn.The main factors which affect the spatial-temporal distribution of primary production are nutrients, temperature and PAR.,particularly nutrients which driven by monsoon-circulation.Based on the improved VGPM model and 7 years average data from SeaWiFS and AVHRR, the annual variation of surface chlorophyll a and primary production in different environments (e.g. Estuary,upwelling and eddies) in the northern South China Sea was analyzed in this study. The results show that the physical-chemical-biological coupling processes driven by monsoon are the main factor controlling the spatial-temporal variation of phytoplankton biomass and primary production. With the changes of physical features (e.g. monsoon, circulation and eddies), chlorophyll a and primary production show great variation.The high values appeared in the Peal River Estuary and coastal zone and the low ones appeared in the shelf anti-cyclonic eddies and the open sea. According to their temporal change,in most cases, the phytoplankton biomass and primary production are high when the Northeast Monsoon prevails and low when the Southwest Monsoon does. Finally, based on the remote sensing data, the annual quantity of fixing carbon in the northern South China Sea was estimated (4.83×107t C/a) and the contributions of the coastal zone,shelf and open sea are 38%,29% and 33%,respectively.更多还原