【作者】 刘晓；

【导师】 黄海军；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 环境科学， 2012， 博士

【摘要】 海水中的悬浮体是重金属、营养盐等不同物质赋存的主要形态，其在近岸环境下的迁移、转化过程是认识陆海相互作用的核心问题。相对于研究较广泛的悬浮体空间格局和平面迁移扩散机制而言，近岸悬浮体垂向通量过程更为复杂，尤其对近岸沉降颗粒物（SPM）的垂向通量和影响因素的分析往往受到仪器设备等观测条件的限制，以往的研究尚较少涉及。作为海水-表层沉积物界面物质、能量交换的载体和影响沉积作用的重要过程参量，SPM对浅海区域动力沉积过程、营养盐循环以及岸滩、海底地形地貌的发育演化过程都具有重要意义。目前在我国近岸海域广泛分布的筏式海带养殖对悬浮体浓度、悬浮泥沙来源、悬浮泥沙输运方式、颗粒物沉降特性可能产生较大的影响。从水动力条件上，大量养殖筏架及海带生物体在海面形成新的上边界层，阻碍了外侧海域波浪能量向近岸的传输，同时消减了海带养殖区内海流流速。在这一动力条件干扰变异的前提下，养殖海域的动力沉积过程尤其是SPM的垂向通量过程如何适应是值得关注的问题。已有的研究多在自然状态下海域进行，而人类活动干预下的近岸海域动力沉积过程研究尚处于起步阶段。本论文以黑泥湾内大规模筏式海带养殖海域为研究对象，研究沉降颗粒物受到筏式海带养殖干扰产生的变异。相关研究成果将为人类活动影响下的近岸物质通量过程研究提供借鉴。大风浪天气对近岸海域沉积环境产生突变性的影响，是改变岸滩、海底地形地貌的重要外力条件。在台风干扰的变异作用下，近岸动力沉积过程尤其是SPM的垂向通量过程如何适应对科学研究与工程实践都具有重要意义。台风过程中动力沉积环境研究，受观测条件和事件突发性限制，国内外较少开展。本研究中观测到一次大型台风天气事件对该海域沉积环境产生影响的全过程，以该观测数据为基础，探讨SPM对台风天气的响应，并基于水动力环境变化对其形成机理进行分析，其研究成果可以为揭示极端天气下动力沉积环境变异提供有益的参考。本研究对黑泥湾养殖区内、外两个站位2007年4～7月同步观测的波浪数据进行对比，使用海带养殖季节（冬季）和非养殖季节（夏季）养殖区内、外多船定点同步连续观测调查资料，分析了筏式海带养殖对波浪的消减作用、对流场空间格局的改变及对悬沙分布运移模式的影响。另外，通过3组自制沉积物捕获器春秋季节采集的两次取样，对养殖区域内不同位置、不同深度水层的沉降颗粒物样品进行了收集，并进行通量计算和有机组分含量、粒度分布等参数测定，对其空间分布及季节变化情况进行了系统分析。并从水动力、颗粒物质来源角度对形成该沉降颗粒物空间分布格局的原因进行分析，揭示了筏式海带养殖通过改变水动力场及物源条件，影响养殖区内沉积环境的规律。运用大型时间系列沉积物捕捉器，收集了2011年台风“梅花”期间沉降颗粒物样品并进行测试，结合观测到的气象、水文要素资料，分析2011年“梅花”台风过程对动力沉积环境的影响，及台风过程中黑泥湾海域沉降颗粒物通量变化。通过上述研究，揭示了黑泥湾海域沉降颗粒物的性质及特点，包括水平及垂直空间分布、季节变化、物质来源、粒度组成、对大规模筏式海带养殖的响应、以及大风浪条件的响应等。通过本研究，对近岸海域动力沉积环境及其影响因子取得了一些新的认识，丰富了陆海相互作用过程和现代沉积动力学理论，对海洋开发和工程实践也具有重要的科学意义。更多还原

【Abstract】 Suspended substance in the sea is the main form of heavy metals, nutrients andother substances. The process of its migration and transformation in the nearshoreenvironment is the key to understand the interaction between land and sea. Researcheson the distribution and spreading mechanism of suspended substance in the horizontalspace are widely carried out, and in comparison the suspended substance vertical fluxnearshore is more complex and seldom studied. The analysis on settling particulatematter (SPM) vertical flux nearshore and its influencing factors are limited by theinstruments and other observation conditions. SPM is of great importance to thedynamics sedimentary process in the shallow sea, nutrient cycle and the developmentprocess of submarine morphology and seafloor relief. Therefore, to carryout observation and research on SPM is necessaryNowadays the widely distributed raft cultivation of sea kelp in costal water areamay have changed the pattern of suspended substance concentration, suspended sandsource, suspend sand transportation and SPM characteristics. Widely distributed raftsand sea kelp hinder the waves from the outer sea from broadcast to the seashore, forma new up boundary layer at the sea surface, and decrease the current speed in thecultivation area. With this change of hydrodynamic condition, the dynamicsedimentary process, especially SPM vertical flux process is in great need of research.Research on this topic is mostly done in the ocean of its natural state, and the study onnearshore dynamic sedimentary process with human disturbance is just in its infancy.In this paper, raft based sea kelp cultivation area is selected as the study object,difference between the dynamic sedimentary environment in and out of the cultivationarea is studied, the modification process of the bay influenced by culture of sea kelp isresearched. The related interaction mechanism and other research results will provide useful references to the study on nearshore matter flux procedure research with theinterferance of human activities.Gale and surge will affect near shore sedimentation dramatically, and they arevery important outer factors to change the seaboard and seafloor relief. Yellow sea isless affected by typhoon weather, but the typhoon process is an important externalcondition to the change and development process of the bank and seabed topography.With the interruption of typhoon, changes of nearshore dynamic sedimentary process,especially SPM vertical flux process, are of great importance to scientific research andocean engineering. Seldom research is carried out on dynamic sedimentary process intime of typhoon because of terrible observation condition and the suddenness of theevent. In this study, one typhoon process and its impacts on dynamic sedimentarycondition are recorded. With this observed data, the change of SPM in typhoonprocess is studied, and related analysis is carried out based on the hydrodynamicenvironment. The research result will provide reference to the study of dynamicsedimentary process in extreme weather conditionIn this study, data from two observation station in and out of raft culture area ofsea kelp from April to July in2007are compared. Other data observed synchronouson different ships, which covered in and out of the raft cultivation area of sea kelp insummer and winter, is used. With these data, the wave decrease function and otherfunctions on the distribution of ocean currents and suspended sand transportation fromculture of sea kelp are studied. In addition, three groups of self-made sediment trapscollected samples in spring and autumn separately, and got SPM samples in differentlocations and depths in the raft cultivation area. The flux, loss of ignition (LOI), grainsize parameters are analyzed to see the changes among seasons and locations. And thereasons of the distribution layout are explained from the viewpoint of hydrodynamicenvironment and suspend sand matter source. Then，the mechanism is revealed onhow raft cultivation affected hydrodynamics environment and matter source, and thenaffected sedimentary environment. Time series sediment trap is used to collect SPMduring the process of typhoon Muifa. Wind, wave data collected near the study area isused to analyze the process of hydrodynamic condition being affected by the passing typhoon. At the end, we explained the reason why and how SPM changed whentyphoon Muifa passed by.With these studies, the nature and characteristics of SPM in Harny Bay arerevealed, including flux, spatial distribution, seasonal changes, matter source, grainsize distribution, impacts from sea kelp cultivation, and impacts from gale and surge.This study revealed the mechanism of near shore dynamic sedimentation and itsinfluencing factors. It enriches the theories on sea-land interaction and moderndynamic sedimentation, and is of great scientific significance to ocean developmentand ocean engineering.更多还原