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1.
Green tides caused by the unusual accumulation of high floating Ulva prolifera have occurred regularly in the Yellow Sea since 2007. The primary source of the Yellow Sea green tides is the attached algae on the Pyropia aquaculture rafts in the Subei Shoal. Ulva prolifera and Blidingia(Italic) sp. are the main species observed on Pyropia aquaculture rafts in the Subei Shoal. We found that U. prolifera has strong buoyancy and a rapid growth rate, which may explain why it is the dominant species of green tides that occur in the China's sea area of the Yellow Sea. The growth rate of floating U. prolifera was about 20%–31% d–1, which was much higher than Blidingia(Italic) sp. There were about 1.7 × 10~4 t of attached algae on the Pyropia aquaculture rafts in May 2012. We found that 39% of attached algae could float when the tide rose in the Subei Shoal, and U. prolifera accounted for 63% of the floating algae. Our analysis estimated that about 4 000 t of attached U. prolifera floated into the surrounding waters of the Subei Shoal during the recycling period of aquaculture rafts. These results suggest that the initial floating biomass of large-scale green tides in the Yellow Sea is determined by the U. prolifera biomass attached to Pyropia aquaculture rafts, further impacting the scale of the green tide. 相似文献
2.
Intensive Pyropia aquaculture in the coast of southwestern Yellow Sea and its subsequent waste, including disposed Ulva prolifera, was speculated to be one of the major sources for the large-scale green tide proceeding in the Yellow Sea since 2007. It was, however, unclear how the detached U. prolifera responded and resumed growing after they detached from its original habitat. In this study, we investigated the growth and photosynthetic response of the detached U. prolifera to various temperature, salinity and irradiance in the laboratory. The photosynthetic rate of the detached U. prolifera was significantly higher at moderate temperature levels(14–27°C)and high salinity(26–32), with optimum at 23°C and 32. Both low(14°C) and highest temperature(40°C), as well as low salinity(8) had adverse effects on the photosynthesis. Compared with the other Ulva species, U. prolifera showed higher saturated irradiance and no significant photoinhibition at high irradiance, indicating the great tolerance of U. prolifera to the high irradiance. The dense branch and complex structure of floating mats could help protect the thalli and reduce photoinhibition in field. Furthermore, temperature exerted a stronger influence on the growth rate of the detached U. prolifera compared to salinity. Overall, the high growth rate of this detached U. prolifera(10.6%–16.7% d~(–1)) at a wide range of temperature(5–32°C) and salinity(14–32) implied its blooming tendency with fluctuated salinity and temperature during floating. The environmental parameters in the southwestern Yellow Sea at the beginning of green tide were coincident with the optimal conditions for the detached U. prolifera. 相似文献
3.
The Subei Shoal is the largest sandy ridge in the southern Yellow Sea and is important source for nutrient loading to the sea. Here, the nutrient fluxes in the Subei Shoal associated with eddy diffusion and submarine groundwater discharge（SGD） were assessed to understand their impacts on the nutrient budget in the Yellow Sea. Based on the analysis of 223 Ra and 224 Ra in the field observation, the offshore eddy diffusivity mixing coefficient and SGD were estimated to be 2.3×108 cm 相似文献
4.
Ulva species can grow rapidly in nutrient-rich habitats causing green tides and marine fouling. A more complete understanding of the reasons behind these outbreaks is urgently required. Accordingly, this study attempts to use microsatellite markers based expressed sequence tag（EST） to analyze the genetic variation of several Ulva prolifera populations in the South Yellow Sea of China. Two hundred and thirty-eight SSRs were identified from 8 179 unique ESTs（6 203 newly sequenced and 1 976 downloaded from NCBI database） and 37 primer pairs were successfully designed according to the ESTs; 11 pairs were selected to detect the genetic diversity and relationship of 69 attached U. prolifera samples and 13 free-floating samples collected from coastal and off-coast areas of the South Yellow Sea. The results of cross-species transferability showed that six of the 11 EST-SSR primers could give good amplification in other five Ulva species and the average allele number was 4.67. Genetic variation analysis indicated that all 82 U. prolifera samples were clearly divided and most samples collected from the same site clustered together as a group in the dendrogram tree produced by unweighted pair-group mean analysis（UPGMA） method and the cluster results showed some consistency with the geographical origins. In addition, 13 free-floating samples（except HT-001-2） were grouped as a single clade separated from the attached samples. 相似文献
5.
黄海苏北浅滩海域春夏季浮游植物时空分布及其控制生态因子 总被引：1，自引：0，他引：1
The Subei Shoal is a special coastal area with complex physical oceanographic properties in the Yellow Sea. In the present study, the distribution of phytoplankton and its correlation with environmental factors were studied during spring and summer of 2012 in the Subei Shoal of the Yellow Sea. Phytoplankton species composition and abundance data were accomplished by Uterm?hl method. Diatoms represented the greatest cellular abundance during the study period. In spring, the phytoplankton cell abundance ranged from 1.59×10~3 to 269.78×10~3 cell/L with an average of 41.80×10~3 cell/L, and Skeletonema sp. and Paralia sulcata was the most dominant species. In summer, the average phytoplankton cell abundance was 72.59×10~3 cell/L with the range of 1.78×10~3 to 574.96×10~3 cell/L, and the main dominant species was Pseudo-nitzschia pungens, Skeletonema sp., Dactyliosolen fragilissima and Chaetoceros curvisetus. The results of a redundancy analysis(RDA) showed that turbidity,temperature, salinity, pH, dissolved oxygen(DO), the ratio of dissolved inorganic nitrogen to silicate and SiO_4-Si(DIN/SiO_4-Si) were the most important environmental factors controlling phytoplankton assemblages in spring or summer in the Subei Shoal of the Yellow Sea. 相似文献
6.
Ship floating condition in regular waves is calculated. New equations controlling any ship＇s floating condition are proposed by use of the vector operation. This form is a nonlinear optimization problem which can be solved using the penalty function method with constant coefficients. And the solving process is accelerated by dichotomy. During the solving process, the ship＇s displacement and buoyant centre have been calculated by the integration of the ship surface according to the waterline. The ship surface is described using an accumulative chord length theory in order to determine the displacement, the buoyancy center and the waterline. The draught forming the waterline at each station can be found out by calculating the intersection of the ship surface and the wave surface. The results of an example indicate that this method is exact and efficient. It can calculate the ship floating condition in regular waves as well as simplify the calculation and improve the computational efficiency and the precision of results. 相似文献
7.
The macroalgal blooms of floating brown algae Sargassum horneri are increasing in the Yellow Sea and East China Sea during the past few years. However, the annual pattern of Sargassum bloom is not well characterized. To study the developing pattern and explore the impacts from hydro-meteorologic environment, high resolution satellite imageries were used to monitor the distribution, coverage and drifting of the pelagic Sargassum rafts in the Yellow Sea and East China Sea from September 2019 to Au... 相似文献
8.
Based on the dynamic theories of water waves and Mindlin plates,the analytic solution of interaction between surface waves and two-dimensional floating elastic plates with edge-restraint is constructed by use of the Wiener-Hopf technique.Firstly,without regard for elastic edge restraint,the wave-induced responses of elastic floating plate analyzed by the present method are in good agreement with the results from literature and experimental results.Therefore,it can be shown that the present method is valid.Secondly,three end-restraint cases(i.e.,the left-end elastic restraints,the both-end elastic restraints,and the right-end elastic restraints)are proposed to reduce the vibration of floating plates,in which the spring is used to connect the sea bottom and the floating plate's left(or right)edge.The relations between the spring stiffness and the parameters of wave-induced responses of floating plates are discussed.Moreover,the effective method to reduce the vibration of floating elastic plates can be obtained through comparison. 相似文献
9.
西南黄海近岸低盐水体的来源与输送机制 总被引：1，自引：0，他引：1
In the southwestern Yellow Sea there is a low-salinity and turbid coastal water,the Subei Coastal Water(SCW).The origins of freshwater contents and thus the dissolved terrigenous nutrients in the SCW have been debated for decades.In this study,we used a well-validated numerical model to quantify the contributions of multiple rivers,i.e.,the Changjiang River in the south and the multiple Subei local rivers(SLRs) in the north,in forming this yearround low-salinity coastal water.It is found that the freshwater contents in the SCW is dominated by the Changjiang River south of 33.5°N,by the SLRs north of 34.5°N,and by both sources in 33.5°–34.5°N.Overall,the Changjiang River contributes ~70% in the dry season and ~80% in the wet season of the total freshwater contents in the SCW,respectively.Dynamics driving the Changjiang River Plume to flow northward is the tidal residual current,which can even overwhelm the wind effects in winter seasons.The residual currents turn offshore near the Old Yellow River Delta(OYRD) by the collision of the two tidal wave systems,which transport the freshwater from both sources into the interior Yellow Sea.Water age experiments show that it takes 50–150 d for the Changjiang River Plume to reach the SCW in the spring and summer seasons,thus there is a 2-month lag between the maximum freshwater content in SCW and the peak Changjiang River discharge.In the winter and autumn seasons,the low salinity in inner SCW is the remnant Changjiang River diluted water arrived in the previous seasons. 相似文献
10.
A Computational Model for Velocity Separation in Shallow Sea 总被引：1，自引：0，他引：1
Based on the hydrodynamical feature and the theoretical velocity profiles of tidal flow and vvind-induced flow in shal-low sea, a computational model is established for the first time, which can separate observed velocity into tidal velocity and wind-induced velocity by use of the least square method. With the model, not only the surface velocities of tidal flow and vvind-induced flow are obtained, but also the bed roughness height is determined and the wind velocity above the wa-ter surface is estimated. For verification of the model, the observed velocity in the Yellow River Estuary and the laborato-ry test is separated, then it is applied to the Yangtze River Estuary. All the results are satisfactory. The research results show that the model is simple in method, feasible in process and reasonable in result. The model is a valid approach to analysis and computation of field dala, and can be applied to separate the observed velocity in shallow sea; at the same time, reasonable boundary conditions of th 相似文献
11.
自2007年以来，黄海海域已连续爆发大规模浒苔绿潮并造成了严重的经济损失。在苏北浅滩条斑紫菜养殖筏架上的定生浒苔被认为是漂浮绿潮藻的主要来源。然而，现阶段对筏架定生绿藻的种源基础并不清楚。因此，在本研究中，我们通过现场调查结合室内试验来揭示了筏架定生绿藻的繁殖体源。同时，为了对黄海大规模绿潮进行防控，我们对防止绿藻在紫菜养殖筏架的附着做了相关研究。结果表明，（1）包括浒苔、缘管浒苔、扁浒苔、曲浒苔以及盘苔这五种海藻的微观繁殖体共同存在于苏北浅滩海域的水体及沉积物中，而且在不同时期它们的比例变化明显。（2）经过去皮处理后的毛竹可明显抑制浒苔微观繁殖体的附着。通过本研究，我们明确分布于苏北浅滩海域的绿藻微观繁殖体是黄海大规模绿潮的种源基础。同时，我们为从源头防控黄海大规模绿潮的发生提供了一个可行的手段。 相似文献
12.
黄海浒苔绿潮防灾减灾现状与早期防控展望 总被引：4，自引：2，他引：2
截至2019年，浒苔绿潮连续12年大规模暴发，对近海生态系统、沿岸环境与社会经济造成严重影响，已经成为黄海最严重的生态环境问题。本文总结了黄海浒苔绿潮防灾减灾现状与成效，分析了存在的问题，然后基于对该绿潮起源与成因的认识，将其早期分为3个关键过程，即浒苔微观繁殖体在养殖设施上的着生与生长过程，定生浒苔脱离附着基形成漂浮浒苔过程，浅滩漂浮浒苔进入深水区形成大面积绿潮过程。最后分别从加强新材料与技术研发防控绿藻着生、强化养殖设施回收管理严控定生绿藻落滩、浅滩汇聚通道拦截打捞等3种途径提出了早期防控措施建议，以期为黄海浒苔绿潮的源头防控提供科学依据。 相似文献
13.
黄海海域大规模绿潮成因与应对策略——“鳌山计划”研究进展 总被引：1，自引：0，他引：1
在青岛海洋科学与技术国家实验室"鳌山计划"支持下,本项目围绕黄海大规模浒苔绿潮的防控减灾,联合山东和江苏两地多个单位协作攻关,于2016年到2018年展开了多学科交叉研究,通过对绿潮藻浒苔(Ulva prolifera)的附着、入海等行为的加密观测,在大规模浒苔绿潮成因机制和防控策略方面取得了重要进展,确认了苏北浅滩源地,确认本海区大量紫菜(Pyropiayezoensis)栽培筏架提供的大面积合适附着基、典型的富营养化环境特点以及北向风生流是黄海大规模浒苔绿潮形成的重要条件。本项目解决了以下几方面的问题:1.锁定关键时段和海域并开展打捞船与无人机配合打捞;2.发现苏北浅滩存在独特浒苔种源;3.定量化研究了紫菜筏架拆除时人为去除筏架及绠绳上的附生绿藻量,明确这一过程大大促进了浒苔大量集中入海,成为浒苔绿潮形成的重要环节;4.定量化研究了浒苔在向北漂移,生物量和分布不断增加的过程;5.依据对浒苔緑潮的源头及其早期发生、发展几个关键过程的科学认识,提出了设置三道防线进行浒苔绿潮防控的策略以及在苏北浅滩开展浒苔绿潮初始生物量源头控制的具体建议。6.评价了浒苔绿潮对生态环境和养殖业危害的同时,关注了高生物量输入对受灾地可能带来生物北侵的生态风险。7.为保障2018年青岛上合峰会,项目组先期提交了绿潮防控建议,部署和开展的各项研究和现场调查结果为绿潮的预测防控提供了有力支撑。同时本项目还针对浒苔绿潮灾害的年际变化、马尾藻(Sargassumsp.)金潮灾害加剧、南黄海"三潮齐发"的复杂态势等新问题展开了观测与研究,为进一步制订更科学高效的防灾减灾方案,阐明全球变化和人类活动影响下的我国近海藻华灾害的演变奠定了基础。 相似文献
14.
黄海绿潮研究:回顾与展望 总被引：4，自引：0，他引：4
自2007年以来,南黄海海域连年发生大规模绿潮(green tides),至2018年已连续12年出现。大规模绿潮对南黄海西部沿海一线的景观、环境和养殖业造成了严重破坏,已经成为黄海海域一类常态化的生态灾害问题。每年夏季,苏、鲁沿海一线地方政府都要投入大量人力物力,对海滩上堆积的绿藻进行收集和处理。针对绿潮问题,我国政府组织相关学者,围绕绿潮起源、成因、危害、监测和防控进行了大量调查和研究工作。经过多年研究,在黄海绿潮原因种及其鉴定方法、黄海绿潮起源地与早期发展过程、影响黄海绿潮的关键因素等方面已经有了比较系统、深入的认识,确认了黄海绿潮的原因种为浒苔(Ulva prolifera),发现黄海绿潮主要起源于南黄海西部的苏北浅滩海域,基本阐明了浅滩区绿潮早期发展的关键过程。浒苔自身的生物学特性、苏北浅滩独特的海域环境特征,以及浅滩区的养殖活动是影响黄海绿潮形成的关键要素。但是,在绿潮原因种浒苔的最初来源、绿潮的生态效应,绿潮演变趋势以及绿潮防控对策等方面仍需进一步开展研究工作。为验证黄海绿潮成因方面的科学认识,对绿潮防控工作提供思路和技术保障,青岛海洋科学与技术国家实验室设立了鳌山科技创新计划项目"近海生态灾害发生机理与防控策略",将黄海绿潮作为一项重要生态灾害问题开展研究,旨在进一步阐明绿潮成因,为绿潮防控提供坚实的科学依据。 相似文献
15.
基于哨兵2号卫星遥感影像的2018年苏北浅滩漂浮绿藻时空分布特征研究 总被引：2，自引：2，他引：0
黄海浒苔绿潮自2007年以来连年暴发，但对漂浮绿藻在其源地—苏北浅滩的分布、发生和发展过程仍缺乏精细刻画。本文主要采用哨兵2号卫星遥感影像，对2018年苏北浅滩的漂浮绿藻信息进行提取，结合地形、微波+红外融合海表温度和CCMP海面风场数据，分析了影响漂浮绿藻时空分布的重要环境因子。结果表明:漂浮绿藻于5月23日在苏北浅滩南部首次通过遥感影像被探测到，在6月逐渐向北发展扩大，在7月中旬消失。漂浮绿藻最早可追溯至浅滩中心紫菜养殖筏架区边缘，而后沿潮沟形成宽度为10～200 m、断续绵延数十千米的条带。在黄海绿潮发展过程中，浅滩持续向北及外海输送漂浮绿藻。在浅滩以北，漂浮绿藻的分布和漂移与海面风向一致。本研究结果可为黄海绿潮的早期预警和防控提供依据。 相似文献
16.
黄海绿潮浒苔漂浮生态型的发现与启示 总被引：1，自引：0，他引：1
黄海绿潮已经成为常态化发生的海洋生态灾害。遗传分析结果表明,黄海绿潮藻主体由浒苔(Ulva prolifera)的单一群体构成。基于其特殊的基因型、表型,及其占据的独特生态位与生活方式,将其命名为"漂浮生态型"(floating ecotype)。浒苔漂浮生态型的发现,为黄海绿潮关键生态学过程的量化表征提供了重要抓手。基于SCAR特异分子标记的示踪研究表明,在绿潮早期浒苔入海阶段,苏北浅滩紫菜筏架发挥了重要作用;在海上暴发漂移阶段,漂浮生态型在漂浮藻中具有极高的优势度。上述发现提示,黄海绿潮存在重要的生物学成因,应加强针对漂浮生态型适应性特征及其遗传基础的比较研究。鉴于漂浮生态型在山东半岛南岸已零星定殖,提出应关注由于种源北侵和紫菜栽培产业北移带来的潜在风险。上述科学认识对于深刻理解黄海绿潮的成因与发生机制、建立可行的灾害防控措施、科学预测黄海绿潮的演变趋势具有重要意义。 相似文献
17.
苏北浅滩沉积物中的大型绿藻微观繁殖体的垂直分布和物种多样性 总被引：1，自引：0，他引：1
本研究通过在2017年秋冬季组织实施的2个绿潮种源调查航次,研究苏北浅滩紫菜养殖区沉积物中的大型绿藻微观繁殖体的垂直分布和物种多样性。对沉积物中的微观繁殖体的定量实验结果表明:表层泥样中绿藻微观繁殖体的丰度最高,随着深度的增加迅速降低。在9月份表层沉积物中丰度为9±2ind./g,而在11月份表层丰度达到98±25ind./g;与9月份相比, 11月份浅滩沉积物中绿藻繁殖体数量呈现出显著升高的趋势。通过对51个绿藻样品的分子鉴定发现:沉积物中存在石莼属(Ulva)、尾孢藻属(Urospora)、盘苔属(Blidingia)等大型绿藻的微观繁殖体;数量占优是石莼属繁殖体,主要包括曲浒苔(Ulva flexuosa)、浒苔(Ulva prolifera)、扁浒苔(Ulva compressa)、缘管浒苔(Ulva linza);其中曲浒苔占据的比例最高,在9和11月份分别达到80.94%和73.33%。在2个调查航次中,都从沉积物中发现了绿潮浒苔的微观繁殖体,这些微观繁殖体是绿潮浒苔在苏北浅滩种源维持的重要方式和关键阶段,也构成了黄海浒苔绿潮连年暴发的"种子库"。 相似文献
18.
自2007年以来, 黄海海域每年的5月初～8月中下旬浒苔(Ulva prolifera)会周期性地暴发与消亡,导致海洋生态环境被破坏以及经济损失。利用2014 年的HJ-1A/1B遥感影像, 利用神经网络监督分类及RULE规则影像重分类动态阈值法, 对2014年的浒苔的漂移路径、各时期影响的海域面积、分布面积以及暴发高峰期的最大面积进行了动态监测。结果表明, 2014年浒苔持续时间为101 d, 5月中旬开始在江苏省盐城市近海出现零星斑点, 分布面积为2.299 km2, 影响面积为1 744.799 km2; 6月初到6月中旬浒苔广泛分布于黄海海域, 分布面积扩大至1 367.145 km2, 达到当年的峰值; 从6月下旬开始, 浒苔进入衰退期, 浒苔分布面积、相对聚集密度均急剧缩小, 但影响面积的峰值出现在该时期; 8月初消亡于青岛附近海岸, 8月20日遥感影像已难以监测到浒苔的存在。2014年黄海海域浒苔经过了“出现—发展—暴发—衰退—消亡”5个发展阶段。 相似文献
19.
苏北浅滩是研究浒苔绿潮早期形成机制的重要区域,该区域紫菜养殖筏架上附生绿藻的群落结构变化对浒苔绿潮的发生具有重要影响,环境因素在其中发挥了重要作用。为了探明导致苏北浅滩绿藻群落结构变化的主要环境因素,本文通过分子生物学和种群生态学方法对筏架附生绿藻群落结构进行了研究,结果表明:(1)苏北浅滩筏架附生绿藻群落主要由浒苔(Ulva prolifera)、盘苔(Blidingia sp.)、缘管浒苔(Ulva linza)、曲浒苔(Ulva flexuosa)和其他绿藻5个类群构成;(2)绿藻群落具有明显的演替现象,环境温度是导致绿藻群落结构变化的关键环境因素,适低温性的绿藻逐渐被浒苔等适应较高温度的绿藻取代;(3)浒苔的生物量从3月的1.65 g/m增加到了5月的31.78 g/m,所占比例也从低于5%达到接近40%,生物量的大量积累为绿潮早期漂浮斑块的形成提供了物质基础。本文研究结果为黄海绿潮的早期预警和防控提供了生态学依据。 相似文献