IOCAS-IR  > 海洋环流与波动重点实验室
春夏季南黄海水文环境季节变化及其生态效应
潘俊
Subtype博士
Thesis Advisor于非
2020-05-17
Degree Grantor中国科学院大学
Place of Conferral中国科学院海洋研究所
Keyword黄海冷水团,绿潮,上升流,中华哲水蚤,环境因子
Abstract

黄海是典型的半封闭性浅海,在该海区春季出现中层冷水、青岛外海冷水团,夏季出现黄海冷水团等特殊的海洋水文现象。绿潮暴发与中华哲水蚤度夏是这两个季节在黄海特殊理化条件下的生态响应过程,因此开展对该海区的春季转换过程以及黄海冷水团演变机制的研究具有重要研究意义。自2007年起,黄海每年爆发浒苔绿潮生态灾害,对近海生态系统造成了诸多不良影响,多年的观测对营养盐有较深入的认识,而对于上升流对其影响的报道较少。同时由于离散化的传统观测和取样方式限制了对多种环境因子影响浮游动物垂直分布和昼夜移动进行综合性的深入探讨,致使浮游动物、浮游植物垂直分布规律与多种生态因子耦合作用的许多细节和机理尚未得到充分阐明。本论文通过近几年现场观测获取的高分辨率水文(温度、盐度等)、生物(中华哲水蚤)与化学(营养盐)资料并结合多年来积累的综合航次实地调查的观测数据,解析春、夏季黄海海区的温、盐结构特征,探讨区域上升流区的营养盐对绿潮过程的影响,并对中华哲水蚤度夏机制进行补充。

本文主要通过2015-2017年(部分季节补充20142019年)的实测资料与中国近海环境调查的资料对比发现:春、夏季黄海海区受前冬的影响较大,如2016年受前冬强寒潮的影响,两季的水温及盐度的态势与20152017年呈现差异。夏季由于太阳辐射作用,黄海海区水温随深度增加递减,并约在l0-30m间形成强的温跃层。跃层之下形成底层的黄海冷水团,该水团具有典型的低温高盐特点,在冷水团边缘区亦形成了较强的温、盐度锋。比对春、夏季水文环境长期观测的历史资料,有助于开展黄海生态系统多角度研究,如系统演变、驱动机理和灾害应对措施等。

春季受黄海沿岸流冷水输入的影响,表层水体的加温及底部黄海暖流的共同作用形成青岛外海中层冷水,并逐步演变进而成为黄海冷水团西侧冷水的一部分。多年的观测资料显示,苏北近岸海域中的营养盐高值区与低盐水区的总体分布趋势对应良好,可以推断陆源淡水输入贡献大量的营养盐,从而满足绿潮暴发的营养需求。通过35°N断面的垂向高分辨率硝酸盐的观测可以验证上升流的存在,该上升流将营养盐从(近)底层沿着上升流携带到(次)表层。黄海是具有典型陆架潮能耗散的海区,潮致混合在黄海不仅控制着冷水团的边界还对环流的结构和强弱产生影响。通过对影响黄海生态系统健康发展的关键过程分析,进而为相应的解决方案提供技术支撑与理论依据。

浮游动物的研究是海洋生态系统动力学研究中的核心问题之一,中华哲水蚤是黄海浮游动物关键种。本文应用新的观测(高频、原位的光学观测)手段,试图将海洋动力过程与区域浮游动物优势种的分布相联系。夏季,通过初步分析采集时间、温跃层强度变化、叶绿素最大层深度与营养盐跃层等相关信息,发现叶绿素最大层位置和强度受温跃层强弱影响,常分布在温跃层内部或下方;叶绿素最大层可以是中华哲水蚤度夏期间的重要食物来源,满足其摄食需求,并规避表层高温的伤害。营养盐跃层附近引起浮游植物生长率的提高称为SCMLSubsurface Chlorophyll Maximum Layer)的形成机制。中华哲水蚤夏季主要分布在黄海冷水团海区的底部或近底部,由于底部水域水温较低、食物较匮乏,生物个体往往会降低其发育率和生殖能力以适应现有的环境条件。多次现场观测发现中华哲水蚤在温跃层内的SCM层出现,推断傍晚到清晨期间,温跃层强度变化较小,温跃层附近出现叶绿素最大层,为中华哲水蚤进入温跃层进行短暂的摄食提供了便利的条件。当环境适宜同时由于能量摄入的需要,跃层附近丰富的饵料是植食性桡足类上升,进而摄食满足自身能量需求的重要影响因素。因此,对于桡足类来说,在夜间短暂停留在SCM层中可能是一个综合权衡的选择。

Other Abstract

Based on the high frequency observation data of hydrology (temperature, salinity), biology (Calanus sinicus) and chemistry (nutrient) collected from field observation in recent years and a large number of field investigations over the years, this paper studies the cold water mass and the process of spring transformation in the Yellow Sea, and the green tide disaster of Enteromorpha prolifera in the Yellow Sea for more than 10 years. The observation of nutrients has a deeper understanding, but there are few reports about the effect of upwelling nutrients on it. Through high frequency and high density nitrate observation, the upwelling nutrients have an important impact on the outbreak and persistence of Enteromorpha proliferata. Due to the limitation of traditional discrete observation and sampling methods, a comprehensive and in-depth study on the effects of various environmental factors on the vertical distribution and migration of zooplankton has been carried out. As a result, many details and mechanisms of the coupling between the vertical distribution of zooplankton and phytoplankton and various ecological factors have not been fully clarified. The distribution pattern of plankton and macroalgae in the Yellow Sea cold water mass should be based on the ecological response to the special physical and chemical conditions of the cold water mass.

This paper mainly compares the measured data of 2015-2017 (some seasons supplement 2014 and 2019). It is found that the spring and summer yellow sea areas are greatly affected by the previous winter, and the strong cold event causes seasonal water temperature and salinity show inter-annual differences. The Yellow Sea warm currents still exist and there are inter-annual differences in strength and weakness. Therefore, spring has different temperature and salinity characteristics. Under the influence of solar radiation in summer, the water temperature in the Yellow Sea decreases gradually with increasing depth, and a strong thermocline is formed between 10 and 30 m. The bottom layer of the Yellow Sea Cold Water Mass runs from the west to the east from the outside of Haizhou Bay to the Yellow Trough area. The northern Jiangsu shoal is a low-salt area, and the salinity of the upper seawater in other areas of the South Yellow Sea is generally consistent. The cold water masses in the Yellow Sea are mainly distributed near the bottom layer of the saline layer. This area has the characteristics of typical low temperature and high salinity. A strong temperature and salinity front has also been formed in the marginal area of the cold water mass. By comparing historical data of long-term observations of the hydrological environment in spring and summer, it is helpful to carry out multi-angle studies of the Yellow Sea ecosystem, such as system evolution, driving mechanisms and disaster response measures.

In spring, due to the influence of the cold water input from the Yellow Sea coastal current, the combined effect of surface water heating and the warm current of the bottom Yellow Sea formed the middle layer cold water outside Qingdao, and gradually evolved to become part of the cold water on the west side of the Yellow Sea Cold Water Mass. The use of observation data for many years shows that the high-nutrient areas in the coastal waters of northern Jiangsu correspond to the low-salinity water areas in general, and a large amount of nutrients are contributed by freshwater input from the land, thus match the nutritional needs of the green tide outbreak. The high-frequency nitrate observation at the 35°N section verifies the existence of the upwelling, carrying nutrients from the (near) bottom layer along the upwelling to the (sub) surface layer; the Yellow Sea is a sea area with typical continental shelf tidal energy dissipation, summer tidal mixing in the Yellow Sea not only controls the boundary of the cold water mass, but also affects the depth of the mixing layer and the structure and strength of the circulation. The existence of the upwelling in the Yellow Sea is also an important way to replenish nutrients during the process of floating Ulva prolifera on the Yellow Sea surface. Through the analysis of the key processes affecting the healthy development of the Yellow Sea ecosystem, we can provide technical support and theoretical basis for the corresponding solutions.

Zooplankton is one of the core issues in the study of marine ecosystem dynamics. Calanus sinicus is a key species of zooplankton in the Yellow Sea. In this paper, new observations (high-frequency, in-situ optical observations) are used to try to connect marine dynamic processes with the distribution of dominant zooplankton species. In summer, through preliminary analysis of the Yellow Sea sea area collection time, thermocline intensity changes, the maximum chlorophyll layer depth and tropotrophic layer, and other relevant information, the thermocline strength determines the location and concentration intensity of the chlorophyll maximum layer, often distributed in the thermocline inside or below; the largest layer of chlorophyll is an important food source during the summer of Calanus sinicus, which can basically meet its feeding needs and avoid the damage of high temperature on the surface. The increase in the growth rate of phytoplankton caused by the nutrient layer is called SCML (Subsurface Chlorophyll Maximum Layer) formation mechanism. Calanus sinicus is mainly distributed at the bottom or near the bottom of the cold water mass of the Yellow Sea in summer. Due to the adverse conditions of low water temperature and relatively scarce food in the bottom water, biological individuals often reduce their development rate and reproductive ability to adapt to the existing environment. condition. On-site observations have repeatedly observed that Calanus sinicus appeared in the SCM layer inside the thermocline. It was inferred that from the evening to the early morning, when the thermocline intensity change was small, the largest layer of chlorophyll appeared near the thermocline. A brief feeding on the floor provides convenient conditions. When the environment is suitable and because of the need for energy intake, the rich bait near the jump layer will induce the rise of herbivorous copepods and ingestion to meet their own energy needs. Therefore, for copepods, staying in the SCML layer at night may be a preferred option.

Language中文
Document Type学位论文
Identifierhttp://ir.qdio.ac.cn/handle/337002/164721
Collection海洋环流与波动重点实验室
Recommended Citation
GB/T 7714
潘俊. 春夏季南黄海水文环境季节变化及其生态效应[D]. 中国科学院海洋研究所. 中国科学院大学,2020.
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