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1.
Seasonal and spatial distributions of phytoplankton biomass associated with monsoon and oceanic environments in the South China Sea 总被引：5，自引：3，他引：2
Seasonal variations of phytoplankton/chlorophyll-a （Chl-a） distribution, sea surface wind, sea height anomaly, sea surface temperature and other oceanic environments for long periods are analyzed in the South China Sea （SCS）, especially in the two typical regions off the east coast of Vietnam and off the northwest coast of Luzon, using remote sensing data and other oceanographic data. The results show that seasonal and spatial distributions of phytoplankton biomass in the SCS are primarily influenced by the monsoon winds and oceanic environments. Off the east coast of Vietnam, Chl-a concentration is a peak in August, a jet shape extending into the interior SCS, which is associated with strong southwesterly monsoon winds, the coastal upwetling induced by offshore Ekman transport and the strong offshore current in the western SCS. In December, high Chl-a concentration appears in the upwelling region off the northwest coast of Luzon and spreads southwestward. Strong mixing by the strong northeasterly monsoon winds, the cyclonic circulation, southwestward coastal currents and river discharge have impacts on distribution of phytoplankton, so that the high phytoplankton biomass extends from the coastal areas over the northern SCS to the entire SCS in winter. These research activities could be important for revealing spatial and temporal patterns of phytoplankton and their interactions with physical environments in the SCS. 相似文献
2.
Transport and distribution of nutrients in anchovy spawning ground to the southern waters of Shandong Peninsula 总被引：1，自引：0，他引：1
INTRODUCTIONNutrients (N ,PandSi)areessentialforphytoplanktongrowthinmarineecosystem .Thetransportandcycling ,distributionandvariationofnutrientsaffectnotonlyonthestructureandfunctionofecosystem ,butalsoonthevariationofthebiologicalresourcesinthesea .ThesouthofShondongPeninsulaisoneofthecentralzonesofurbanandagriculturalactivities.Al thoughthereisnodirectlargeriverinput,seasonalvariationofchemicalenvironmentisobviousintheHaizhouBay .Inspringandsummer,thedistributionsofnutrientsareinflu… 相似文献
3.
Julian P. McCreary Jr Kevin E. Kohler Raleigh R. Hood Donald B. Olson 《Progress in Oceanography》1996,37(3-4)
A coupled, physical-biological model is used to study the processes that determine the annual cycle of biological activity in the Arabian Sea. The physical model is a
system with a surface mixed layer imbedded in the upper layer, and fluid is allowed to move between layers via entrainment, detrainment and mixing processes. The biological model consists of a set of advective-diffusive equations in each layer that determine the nitrogen concentrations in four compartments: nutrients, phytoplankton, zooplankton and detritus. Coupling is provided by the horizontal-velocity, layer-thickness, entrainment and detrainment fields from the physical solution. Surface forcing fields (such as wind stress and photosynthetically active radiation) are derived from monthly climatological data, and the source of nitrogen for the system is upward diffusion of nutrients from the deep ocean into the lower layer. Our main-run solution compares favorably with observed physical and biological fields; in particular, it is able to simulate all the prominent phytoplankton blooms visible in the CZCS data. Three bloom types develop in response to the physical processes of upwelling, detrainment and entrainment. Upwelling blooms are strong, long-lasting events that continue as long as the upwelling persists. They occur during the Southwest Monsoon off Somalia, Oman and India as a result of coastal alongshore winds, and at the mouth of the Gulf of Aden through Ekman pumping. Detrainment blooms are intense, short-lived events that develop when the mixed layer thins abruptly, thereby quickly increasing the depth-averaged light intensity available for phytoplankton growth. They occur during the fall in the central Arabian Sea, and during the spring throughout most of the basin. In contrast to the other bloom types, entrainment blooms are weak because entrainment steadily thickens the mixed layer, which in turn decreases the depth-averaged light intensity. There is an entrainment bloom in the central Arabian Sea during June in the solution, but it is not apparent in the CZCS data. Bloom dynamics are isolated in a suite of diagnostic calculations and test solutions. Some results from these analyses are the following. Entrainment is the primary nutrient source for the offshore bloom in the central Arabian Sea, but advection and recycling also contribute. The ultimate cause for the decay of the solution's spring (and fall) blooms is nutrient deprivation, but their rapid initial decay results from grazing and self shading. Zooplankton grazing is always an essential process, limiting phytoplankton concentrations during both bloom and oligotrophic periods. Detrital remineralization is also important: in a test solution without remineralization, nutrient levels drop markedly in every layer of the model and all blooms are severely weakened. Senescence, however, has little effect: in a test solution without senescence, its lack is almost completely compensated for by increased grazing. Finally, the model's detrainment blooms are too brief and intense in comparison to the CZCS data; this difference cannot be removed by altering biological parameters, which suggests that phytoplankton growth in the model is more sensitive to mixed-layer thickness than it is in the real ocean. 相似文献
4.
《Deep Sea Research Part I: Oceanographic Research Papers》2001,48(5):1139-1168
Mesoscale physical and biological processes are examined at the Gulf Stream front by means of a 4-D simulation including physical and biological data assimilation. The data assimilated are from Leg 1 of the Fall BIOSYNOP cruise, 21 Sept.–8 Oct. 1988, and GULFCAST data for the same period. Focus is on the vertical velocities at the front, the vertical and horizontal transports of nutrients and plankton, and the impact of these transports on phytoplankton biomass, production and organic particle export. It was found that while jet meandering enhances new production at the front, primary production and phytoplankton concentration at the front are not significantly enhanced over those of Slope water. Winds during this period also have little impact on productivity at the front, due to their high temporal variability. Ring–stream interactions, however, significantly increase the net vertical and meridional transports of nutrients and plankton and can lead to phytoplankton patchiness at the front. This emphasizes the importance of submesoscale events between interacting mesoscale physical features in the transport of nutrients and plankton, and in explaining the observations. The enhanced phytoplankton concentrations observed during BIOSYNOP are found to be primarily due to advection (convergence) rather than in situ biological growth. 相似文献
5.
根据2005年3～12月14艘中国渔船在智利外海的竹筴鱼生产统计数据和卫星遥感反演的海表温度、叶绿素浓度,分析智利外海竹筴鱼中心渔场的时空变动以及渔场与环境因子的关系.结果表明,随着南半球秋季转入冬季,竹筴鱼中心渔场相应地由南向北、由东向西推移,10月份渔场达到最北端,春末夏初开始南撤;智利外海竹筴鱼渔场的表层水温大致为12～16℃,中心渔场为14～15℃,月间略有差异;渔场的叶绿素质量浓度大致为0.06～0.12 mg/m~3,当渔场的叶绿素质量浓度处于0.08～0.10 mg/m~3时,渔船作业频次和竹筴鱼产量最高. 相似文献
6.
Tamiji Yamamoto Toshiya Hashimoto Hidetaka Takeoka Tenji Sugiyama Osamu Matsuda 《Journal of Oceanography》2000,56(2):131-139
Field observations were conducted to examine the processes governing the phytoplankton distribution and photosynthetic activity in and around a tidal front formed in Iyo Nada, the Seto Inland Sea, Japan. The existence of a middle layer intrusion, which, it has been suggested, moves from the mixed region to the stratified region of the tidal front, was ascertained by the phytoplankton distribution in addition to a T-S diagram. Skeletonema costatum, which originally inhabited the mixed region, was used as the indicator to reveal the intrusion. However, the tip of water containing the S. costatum population did not extend deeply into the stratified region. The velocity of the intrusion seemed to be slow enough to make biological processes, such as nutrient uptake by phytoplankton and subsequent growth, as well as the decrease in cell density due to zooplankton grazing, dominate during the transportation. The patchy distribution of copepod nauplii implied that grazing has an influence on the distribution pattern of phytoplankton. The location of high photosynthetic activity did not coincide spatially with the center of high phytoplankton biomass, suggesting the importance of these biological processes. Therefore, it is considered that the middle layer intrusion plays a role as an inducer of subsequent biological processes at the tidal front by not only supplying nutrients from the mixed region but also by increasing the vertical diffusivity. 相似文献
7.
Sang Heon Lee Jongseong Ryu Jung-woo Park Dabin Lee Jae-Il Kwon Jingping Zhao SeungHyun Son 《Ocean Science Journal》2018,53(3):475-485
The Bering and Chukchi seas are an important conduit to the Arctic Ocean and are reported to be one of the most productive regions in the world’s oceans in terms of high primary productivity that sustains large numbers of fishes, marine mammals, and sea birds as well as benthic animals. Climate-induced changes in primary production and production at higher trophic levels also have been observed in the northern Bering and Chukchi seas. Satellite ocean color observations could enable the monitoring of relatively long term patterns in chlorophyll-a (Chl-a) concentrations that would serve as an indicator of phytoplankton biomass. The performance of existing global and regional Chl-a algorithms for satellite ocean color data was investigated in the northeastern Bering Sea and southern Chukchi Sea using in situ optical measurements from the Healy 2007 cruise. The model-derived Chl-a data using the previous Chl-a algorithms present striking uncertainties regarding Chl-a concentrations – for example, overestimation in lower Chl-a concentrations or systematic overestimation in the northeastern Bering Sea and southern Chukchi Sea. Accordingly, a simple two band ratio (Rrs(443)/Rrs(555)) algorithm of Chl-a for the satellite ocean color data was devised for the northeastern Bering Sea and southern Chukchi Sea. The MODIS-derived Chl-a data from July 2002 to December 2014 were produced using the new Chl-a algorithm to investigate the seasonal and interannual variations of Chl-a in the northern Bering Sea and the southern Chukchi Sea. The seasonal distribution of Chl-a shows that the highest (spring bloom) Chl-a concentrations are in May and the lowest are in July in the overall area. Chl-a concentrations relatively decreased in June, particularly in the open ocean waters of the Bering Sea. The Chl-a concentrations start to increase again in August and become quite high in September. In October, Chl-a concentrations decreased in the western area of the Study area and the Alaskan coastal waters. Strong interannual variations are shown in Chl-a concentrations in all areas. There is a slightly increasing trend in Chl-a concentrations in the northern Bering Strait (SECS). This increasing trend may be related to recent increases in the extent and duration of open waters due to the early break up of sea ice and the late formation of sea ice in the Chukchi Sea. 相似文献
8.
Introduction The growth of phytoplankton, which is the main primary producer in the ocean, is always limited by some nutrients such as nitrogen and phosphorus. This limitation has spacial variation, and even in the same area, the nitrogen and phosphorus limitation has seasonal alternation [1]. There are many ways to determine the nutrient limitation of phytoplankton growth. Among them, the enrichment bioassay is the closest to the natural condition and is accepted by many scholars [2-7]. In r… 相似文献
9.
浮游植物作为食物链的基础,对海洋生态系统具有重要影响。黄海作为我国重要的渔场,渔业资源面临枯竭的危险,因此对该区浮游植物进行研究具有重要意义。叶绿素a浓度是反映浮游植物生物量的重要指标。利用谷歌地球引擎平台对2002-2018年的MODIS Aqua叶绿素a浓度数据进行处理,并研究其时空分布与变化特征,然后结合区域气候、水文与地理特征以及海洋表面温度、风速、盐度、光合有效辐射和混合层厚度数据分析了其分布与变化的原因。研究发现:受陆源营养物质输入、近岸上升流以及黄海中央冷水团影响,叶绿素a浓度分布呈现由近岸向黄海中部递减特征;在季风、气候、水文的控制下,受风速、海洋表面温度、光合有效辐射、中央冷水团的影响,叶绿素a浓度的最大值出现在4月份,而最小值出现在6、7月份;受苏北沿岸海域海水污染和水体富营养化影响,沿岸海域盐度明显增加,海州湾叶绿素a浓度增速较大;影响黄海叶绿素a浓度变化的环境因子较复杂,除了部分月份存在显著的相关影响因子外,在全年和各季中不存在主导影响因子。 相似文献
10.
Primary productivity (PP) and phytoplankton structure play an important role in regulating oceanic carbon cycle. The unique seasonal circulation and upwelling pattern of the South China Sea (SCS) provide an ideal natural laboratory to study the response of nutrients and phytoplankton dynamics to climate variation. In this study, we used a three-dimensional (3D) physical–biogeochemical coupled model to simulate nutrients, phytoplankton biomass, PP, and functional groups in the SCS from 1958 to 2009. The modeled results showed that the annual mean carbon composition of small phytoplankton, diatoms, and coccolithophores was 33.7, 52.7, and 13.6 %, respectively. Diatoms showed a higher seasonal variability than small phytoplankton and coccolithophores. Diatoms were abundant during winter in most areas of the SCS except for the offshore of southeastern Vietnam, where diatom blooms occurred in both summer and winter. Higher values of small phytoplankton and coccolithophores occurred mostly in summer. Our modeled results indicated that the seasonal variability of PP was driven by the East Asian Monsoon. The northeast winter monsoon results in more nutrients in the offshore area of the northwestern Luzon Island and the Sunda Shelf, while the southwest summer monsoon drives coastal upwelling to bring sufficient nutrients to the offshore area of southeastern Vietnam. The modeled PP was correlated with El Niño/Southern Oscillation (ENSO) at the interannual scale. The positive phase of ENSO (El Niño conditions) corresponded to lower PP and the negative phase of ENSO (La Niña conditions) corresponded to higher PP. 相似文献
11.
本文利用南海海洋再分析产品REDOS(Reanalysis Dataset of the South China Sea)和风场资料CCMP(Cross-Calibrated,Multi-Platform),通过能量诊断探讨了越南沿岸南海西边界流(南海贯穿流主体部分)区域夏季(6—9月)涡流相互作用的年际变化特征以及平均流对中尺度过程的贡献。结果显示,在季风和西边界强流、南海贯穿流的共同影响下,越南沿岸东向急流和双涡结构的能量分布和收支有显著的年际差异。尽管涡动能(EKE,Eddy Kinetic Energy)和涡动有效势能(EPE,Eddy available Potential Energy)的量级基本一致,但二者在水平和垂向空间分布上存在明显差异,这与夏季风影响下的南海西部边界流,越南离岸流的上层海洋密度梯度、流速大小和剪切导致的斜压、正压不稳定性等因素相关。同时随着深度的增加,密度梯度变化相对水平速度剪切对海洋涡流过程的影响逐渐凸显。EKE能量收支分析表明,压强与风应力主要做正功,是维持EKE稳定的主要能量来源,而EKE平流项既可以促进涡旋的增长,也会造成涡旋的消耗,对EKE的年际变率影响比较显著。正压不稳定导致的能量转换主要影响南海西部边界流区域,并存在显著年际变化,并且在风和平均流的影响下,沿贯穿流方向存在显著空间分布差异。越南离岸流正异常年,整体呈现平均流向涡旋传递能量;负异常年,出现EKE反哺平均动能的情况。 相似文献
12.
2012年春季渤海中部及邻近海域叶绿素a与环境因子的分布特征 总被引：3，自引：1，他引：2
分析了2012年春季渤海中部及其邻近海域32个站点叶绿素a和环境因子的空间分布特征及其相互关系。结果发现:渤海中部靠近黄河口邻近水域相对于其他水域,呈现出相对较高的水温和较低的盐度,这与黄河淡水输入以及近岸水深相对较浅有密切关系。营养盐浓度在空间分布上表现为黄河口附近海域较高,在垂直分布上表现为中、底层高于表层,显示出黄河水输入与沉积物营养盐再释放的影响;此外,营养盐浓度与结构显示,渤海海域存在明显的磷和硅限制,磷限制尤其严重。叶绿素a浓度的空间分布显示,表层叶绿素a浓度的高值区出现在渤海湾湾口处,而中层与底层的叶绿素a浓度高值区出现在渤海中部。主成分分析结果表明,磷酸盐和温度是影响表层叶绿素a浓度的重要因素,而中、底层叶绿素a浓度主要受磷酸盐的影响。 相似文献
13.
长江口外潮汐混合和低盐度羽流形成的泥沙锋和羽状锋对浮游植物与环境因子的空间分布具有重要控制作用。本研究依据 2019 年夏季长江口及邻近海域典型断面叶绿素 a （Chl-a） 浓度和环境因子的调查结果,以锋面为边界,探讨了不同区域 Chl-a 浓度与环境因子的分布特征及相互关系,以期深入了解锋面的生态效应。结果表明,在泥沙锋以内的近岸区域,水体垂直混合均匀;受长江径流输入和泥沙锋“屏障”作用影响,总悬浮物 （TSM） 和营养盐浓度最高,其中TSM为 220.0± 275.3 mg/L,溶解无机氮 （DIN）、溶解无机磷 （DIP） 和溶解硅酸盐 （DSi） 分别可以达到 94.7±21.2 umol/L、 0.85±0.33umol/L 和 95.3±22.6 umol/L;高浓度 TSM 引起显著的光限制效应,导致 Chl-a 浓度较低 （1.7 ±0.5 ug/L）。在羽状锋以外的区域,出现垂直层化现象;表层海水的 TSM 和营养盐显著降低,其中 TSM 为 5.1 mg/L,DIN、DIP 和 DSi 分别为1.0 umol/L、0.03 umol/L 和 2.4 umol/L;Chl-a浓度受到营养盐供应不足的影响,浓度仅为 0.2ug/L。高浓度的 Chl-a （7.5±4.1±g/L） 主要出现在泥沙锋和羽状锋之间的过渡区域,该区域营养盐得到长江径流与上升流的补充;同时,由于大量 TSM在泥沙锋快速沉降,缓解了水体的光限制效应,有利于浮游植物的生长和积累。研究结果验证了泥沙锋和羽状锋对 TSM 与营养盐的重要控制作用,这对于理解长江口及邻近海域藻类灾害高发区的成因具有科学参考价值。 相似文献
14.
长江口和杭州湾海域生物生产力锋面及其生态学效应 总被引：39，自引：10，他引：39
通过分析海洋生态学资料并结合卫星遥感、渔场及赤潮等资料,发现长江口和杭州湾及其毗邻海域生物生产力的锋面,在离长江口门和杭州湾口约100 km的长江冲淡水中部海域出现蓝细菌丰度、浮游植物现存量和初级生产力以及浮游动物的最大值,该锋面的存在和位置被水色遥感所确认.光和营养盐在此呈现最佳的权衡.在该锋区悬浮体浓度小于5 mg/dm3,盐度为25～30.在该锋面的西侧高的悬浮体浓度造成了浮游植物的光限制,其东侧距长江口和杭州湾口较远,陆源营养盐被稀释,加之浮游植物的消耗,造成了营养盐的限制.夏季水体的层化,增强了水体的垂直稳定,使这种分布格局更加显著.由于细菌多附着在悬浮颗粒物的表面,细菌丰度的最大值出现在近口门区的最大浊度带,在向外海方向随着悬浮体的沉降细菌丰度迅速降低.在生物生产力锋面,浮游植物的旺发导致水体跃层之上高溶解氧浓度和低营养盐浓度,尤其是PO4被耗尽,同时浮游动物饵料的丰富,造成浮游动物旺发;由于蓝细菌的快速增殖,其流式细胞测定的细胞粒径变小.生物生产力锋面的出现产生了显著的生态学效应,一方面造成某些经济鱼类产卵和索饵场的形成,例如鲐鲹鱼、马鲛鱼等;另一方面造成赤潮多发区和底层水缺氧区. 相似文献
15.
1Introduction TheSouthChinaSea(SCS)isasemi enclosed tropicalmarginalseawithcomplextopographyand numerousislands(seeFig.1)andtheonlydeep channelbetweentheSCSandtheadjacentPhilippine SeaistheLuzonStrait.TheclimateoftheSCSis controlledbytheEastAsianmonsoonsy… 相似文献
16.
利用 SeaWiFS卫星遥感叶绿素质量浓度及TRMM微波遥感海表温度产品,研究了南海海表叶绿素a的季节变化特征及其同海表温度的关系。研究结果表明,南海叶绿素质量浓度具有很强的季节变化:通常低叶绿素质量浓度(<0.12 mg. m-3)出现在弱风、高海表温度(>28 °C)的春、夏季节;高叶绿素质量浓度(>0.13 mg·m-3)出现在有较强风速和较低海表温度(<27 °C)的冬季。线性回归分析显示,南海叶绿素质量浓度同海表温度呈显著负相关关系。尽管在南海南部、南海中部、南海西部及吕宋西北部4个代表子区域的显著性有所差异,但都暗示温度变化所反映的垂向层化调控了营养盐质量浓度和浮游植物量变化。可见,温度可能是影响海洋上层稳定程度及垂向交换强度的重要指标,从而可能调控营养盐及浮游植物的变化。 相似文献
17.
Lee Minji Kim Jin Ho Kim Yun-Bae Park Chan Hong Shin Kyoungsoon Baek Seung Ho 《海洋学报(英文版)》2020,39(2):107-122
The East Sea(Sea of Japan)is a marginal,semi-closed sea in the northwestern Pacific.The Ulleung Basin area,which is located near the subpolar front of the East Sea,is known to have high primary production and good fisheries in spring season.After episodic wind-driven events during the spring of 2017,horizontal and vertical profiles of physical chemical biological factors were investigated at 29 stations located in the Ulleung Basin area.In addition,growth responses of phytoplankton communities to nutrient additions were evaluated by bioassay experiments to understand the fluctuation of phytoplankton biomass.Because of strong northwestern wind,phytoplankton biomass was scattered and upwelling phenomenon might be suppressed in this season.The phytoplankton abundances in the coastal stations were significantly higher than offshore and island stations.In contrast,the nutrient and chlorophyll a(Chl a)concentrations and the phytoplankton biomass were quite low in all locations.Bacillariophyceae was dominated group(>75.1%for coastal,40.0%for offshore and 43.6%for island stations).In the algal bioassays,the phytoplankton production was stimulated by N availability.The in vivo Chl a values in the+N and+NP treatments were significantly higher than the values in the control and the+P treatments.Based on the field survey,the higher nutrients in coastal waters affected the growth of diatom assemblages,however,little prosperity of phytoplankton was observed in the offshore waters despite the injection of sufficient nutrients in bioassay experiments.The growth of phytoplankton depended on the initial cell density.All of results indicated that a dominant northwestern wind led to a limited nutrients condition at euphotic layers,and the low level of biomass supply from the coasts resulted in low primary production.Both supplying nutrients and introducing phytoplankton through the currents are critical to maintain the high productivity in the Ulleung Basin area of the East Sea. 相似文献
18.
2005年6月初在台湾海峡海坛岛邻近海域进行了3个断面的水体温度、盐度、浊度、荧光叶绿素a调查,通过上述要素分析,阐述了该海域上升流发生阶段的分布特征以及荧光叶绿素a、水体浊度的变化规律,指出荧光叶绿素a的分布特征除与营养盐的限制相关外,水体浊度对荧光叶绿素a的分布也起着控制作用,同时在上升流涌升最强烈的地区往往出现了浊度最大值,可能与底层物质的再悬浮相关。该研究对于深化认识区域海洋学过程以及影响具有积极意义。 相似文献
19.
The potential suppression of copepods on appendicularians was found in field and experimental conditions. The abundance and distribution of appendicularians and planktonic copepods were studied with reference to their correlations during summer on the northwest continental shelf of the South China Sea (SCS). Based on the topography and water mass of the surveyed region, it was divided into three sub-regions: Region I (inshore waters of the east Leizhou Peninsula) with low temperature, salinity and high chlorophyll a (Chl a) concentration, Region II (inshore waters of the east and southeast Hainan Island) with low temperature, high salinity and moderate Chl a concentration and Region III (offshore waters from the Leizhou Peninsula to Hainan Island) with high temperature, high salinity and low Chl a concentration. The species richness of appendicularians and copepods increased from the inshore to offshore waters, and high values were observed in Region III. The distribution of appendicularian and copepod abundance decreased generally from the inshore to offshore waters, with the highest values at Region I. Our results suggest that the distribution patterns of appendicularians and copepods differed significantly, as a result of the influence of physical and biological factors. The negative impact of pelagic copepods on appendicularians was not found based on in situ data in the northwest continental shelf of SCS. 相似文献
20.
利用模糊综合方法评价长江口海水富营养化水平 总被引：8，自引：0，他引：8
根据2004年4个季度的调查数据,以化学需氧量(COD)、溶解无机氮(DIN)、磷酸盐(PO4-P)、叶绿素a(Chl-a)和溶解氧(DO)作为评价指标,运用模糊综合评价模型对长江口海域海水富营养化水平进行评价。结果表明,约有一半的调查站点呈现富营养化,长江口门及冲淡水区(122.5°E以西)富营养化程度较高,外海(122.5°E以东)富营养化程度较低,富营养程度从外海向近岸增加。富营养化区域全年大部分都分布于盐度小于20的一侧,呈明显的季节分布和区域分布,表明长江口海域的富营养化水平主要受到长江冲淡水的控制。 相似文献