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1.
南海大鹏湾盐田海域骨条藻数量的多元分析   总被引:15,自引:3,他引:15  
1990年及1991年3月30日-5月30日,在南海大鹏湾盐田海域设点测定骨条藻数量及各环境要素,以逐步回归,主成分分析及判别分析的方法,分析该海区骨条藻数量与环境因子的关系。1990年4、5月与1991年4,5月骨条藻数量差异与该期间环境因子值差异显著有关;初步提出用三维主成分分析图及判别分析方程作为盐田海域骨条材料潮预报的方法。  相似文献   

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The distribution of Leptomithrax longipes (Thomson), on the continental shelf east of the Otago Peninsula appears to be affected by females migrating into deeper water at the edge of the shelf. The presence of immature crabs inshore suggests the existence of an onshore current. Nine sexually indeterminate individuals were examined; their combination of male and female characters indicated that they were males undergoing a process of feminisation. Tissue and blood smears contained a bacterium which was possibly causing this feminisation.  相似文献   

4.
史磊  宋毅宁  秦宏 《海洋科学》2021,45(4):40-50
自20世纪80年代以来,我国出台了众多海洋捕捞相关政策,厘清这些政策变迁规律对海洋捕捞业的健康发展具有重要意义。本文对1986年以来我国海洋捕捞业的政策文本展开量化分析,构建政策时间维度、政策工具维度、政策价值维度三维政策文本分析框架,梳理当前捕捞业政策变迁和结构特征,并深入分析了捕捞业政策与现实的匹配性。研究发现,海洋捕捞业的部分政策目标之间存在一定的冲突和矛盾;政策工具体系全面,但不同政策工具数量分布不均衡;早期政策的经济价值取向突出,社会、生态价值相对不足,需要适时调整政策价值取向。未来应明确政策目标,推动海洋捕捞管理范式由投入控制向产出控制的转变;优化政策工具组合,引导渔民自觉养护海洋渔业资源,提高海洋捕捞业政策的有效性;整合政策价值取向,协调产业发展、资源养护和渔民利益的关系,推动海洋捕捞可持续发展。  相似文献   

5.
辽东湾鲅鱼圈赤潮与环境因子分析   总被引:5,自引:2,他引:3  
赤潮的发生是一个复杂的生态变化过程,赤潮藻的快速增殖不仅需要丰富的营养物质基础,适宜的物理环境条件亦是不可或缺的,是诸如水文、气象、物理、化学和生物因子综合作用的结果。辽东湾为我国北方海域赤潮最频繁海域。本文就1998年~2003年5月间发生在辽东湾的赤潮过程,从天气形势、水文气象环境动力因子的角度对赤潮的暴发进行分析研究与统计,得出了赤潮暴发的相似天气形势及水文气象环境动力因子的变化规律,试图探索其预报的可能性。并就2001年北海分局在鲅鱼圈监测到的赤潮水文、气象、物理、化学等环境因子数据,运用正交分析、聚类分析多元统计分析方法,分析了赤潮发生过程中环境因子的变化规律,试图寻找影响赤潮的主导因子与重要因子。  相似文献   

6.
Settlement of Ostrea lutaria on sand‐cement‐plastered asbestos plates held in steel frames on the bottom of Foveaux Strait was studied from March 1965 to April 1967. Spat mortality over the period of plate exposure (about one month) was very low (maximum of 3 percent) and was greatest shortly after settlement. There was no evidence that mortality was due to predation. Essentially the same seasonal pattern of settlement was observed each year. Eighty to 90 percent of spat settled between mid December and mid February in both summers; settlement occurred as early as October; some was observed as late as July.

Results of field experiments suggest some very tentative conclusions on the settlement behaviour of O. lutaria: (1) The larvae are benthopelagic and remain on the bottom in strong current conditions. (2) Light stimulates swimming of larvae in still water. (3) In still water and low light intensities of the area larvae tend to swim upward toward the light. (4) In still water and dim light of the area larvae settle predominantly on under surfaces. (5) In still water in the absence of light larvae settle predominantly on upper surfaces. (6) Under the conditions of current and light in the multiplate frames used to sample spatfall here, larvae settle mainly on upper surfaces. (7) Larvae tend to crawl up inclined surfaces before settling.

The results indicate that larval behaviour may be changed by small alterations of light intensity and current. The contradictory nature of surface angle preferences found by other workers for various species of Ostrea and Crassostrea may have been due to such small variations caused by the experimental techniques. It is possible that the settlement behaviour of all species of these genera is similar.  相似文献   

7.
The ˜4000 m thick and ∼20 Myr deep-water sedimentary fill of the Upper Cretaceous Magallanes Basin was deposited in three major phases, each with contrasting stratigraphic architecture: (1) the oldest deep-water formation (Punta Barrosa Formation) comprises tabular to slightly lenticular packages of interbedded sandy turbidites, slurry-flow deposits, and siltstone that are interpreted to record lobe deposition in an unconfined to weakly ponded setting; (2) the overlying, 2500 m thick and shale-dominated Cerro Toro Formation includes a succession of stacked conglomeratic and sandstone channel-fill deposits with associated finer-grained overbank deposits interpreted to record deposition in a foredeep-axial channel-levee system; (3) the final phase of deep-water sedimentation is characterized by sandstone-rich successions of highly variable thickness and cross-sectional geometry and mudstone-rich mass transport deposits (MTDs) that are interpreted to record deposition at the base-of-slope and lower slope segments of a prograding delta-fed slope system. The deep-water formations are capped by shallow-marine and deltaic deposits of the Dorotea Formation.These architectural changes are associated with the combined influences of tectonically driven changes and intrinsic evolution, including: (1) the variability of amount and type of source material, (2) variations in basin shape through time, and (3) evolution of the fill as a function of prograding systems filling the deep-water accommodation. While the expression of these controls in the stratigraphic architecture of other deep-water successions might differ in detail, the controls themselves are common to all deep-water basins. Information about source material and basin shape is contained within the detrital record and, when integrated and analyzed within the context of stratigraphic patterns, attains a more robust linkage of processes to products than stratigraphic characterization alone.  相似文献   

8.
The terrigenously-dominated marine shales which were deposited in the lower Eocene Pinghu Formation were thought to be a potential source rock in the Xihu Depression of the East China Sea Shelf Basin. However, the exceptionally high total organic carbon content (TOC, >6% on average) of the tidal sand ridge samples was not compatible with their sedimentary environment, indicating coal-bearing sedimentary debris may have been transferred from the coast to the ocean. In this study, new sights into the origins and supply of organic materials in the coastal environment were proposed in the neritic organic matter of the Eocene Pinghu Formation. A discriminant model was developed using plynofacies analysis data to pinpoint the source of organic materials in marine source rocks. The discrimination results suggested that marine mudstones were associated with tidal flat mudstones rather than deltaic ones. The biomarker characteristics of mudstones deposited in various environments support this assertion, indicating that the supply of plant materials in tidal flats is the primary organic matter source for the marine environment. The organic matter abundance was elevated in tidal flats due to their superior preservation conditions. Additionally, the lithological assemblage of tidal flats suggests that tidal currents can scour marshes and then transport dispersed terrigenous organic materials to neritic areas. These findings indicate that coal-bearing sedimentary debris was likely transferred from the coast to the ocean, and tidal currents are thought to be the dominant mechanism driving organic matter from the tidal to the marine environment.  相似文献   

9.
海水中锌、镉、铅、铜的微分电位溶出分析   总被引:1,自引:0,他引:1       下载免费PDF全文
提出一种简便快速、直接测定海水中锌、镉、铅、铜的微分电位溶出分析方法,海水适宜酸度为(3.0—4.5)×10~(-3)mol/LHNO_3,适宜盐度1.6—31。电解(富集)时间600s时,检出限为0.02μg/L Zn~(2+),0.02μg/L Cu~(2+),0.01μg/L Cd~(2+),0.006μg/L Pb~(2+)。在青岛近岸海水中加1.0μg/L Zn~(2+),Pb~(2+),Cu~(2+)和0.5μg/L Cd~(2+),测定的相对标准偏差分别为2.9%,3.1%,5.8%和5.1%。应用于近岸海水及中国标准海水中锌、镉、铅、铜的测定,结果满意。  相似文献   

10.
Seismic stratigraphic and structural analyses of the northwest Phu Khanh Basin, offshore Central Vietnam, based on 2-D seismic data, indicate that the initial rifting began during the latest Cretaceous? or Palaeogene controlled by left-lateral transtension along the East Vietnam Boundary Fault Zone (EVBFZ) and northwest–southeast directed extension east of the EVBFZ. Rifting stopped due to transpression during middle Oligocene times but resumed by left-lateral transtension during the Late Oligocene. Thick sequences of lacustrine and alluvial sediments were deposited during the Palaeogene rift periods. The Late Oligocene rifting ended due to inversion, triggered by right-lateral wrenching near the Palaeogene–Neogene boundary. Following the onset of this inversion regional uplift and volcanism took place in the southern half of the study area and contemporaneous subsidence and transgression took place farther north, leading to widespread carbonate deposition. As the right-lateral wrenching decreased during the early Neogene, thermal subsidence and siliciclastic sedimentation became dominant, resulting in the buildup and southward propagation of the shelf slope. Sediment accumulation and subsidence rates increased after the Middle Miocene times due to eastward tilting of Central Vietnam and the adjacent offshore area.  相似文献   

11.
陈雅琦  梁健  郭永军  李永仁 《海洋科学》2022,46(10):122-128
为研究硬壳蛤形态性状对体质量(Y)、软体质量(Y1)及肥满度(K)的影响,测量硬壳蛤的壳长(X1)、壳宽(X2)、壳高(X3)、体质量(Y)和软体质量(Y1)等指标,并进行相关性分析、多元回归分析和通径分析。结果表明:体质量变异系数最高,壳宽与体质量相关系数最高(0.970)、壳长与软体质量相关系数最高(0.946)、壳长与肥满度相关系数最高(0.203)。壳宽对体质量直接作用最大(0.145)、壳长对软体质量直接作用最大(1.113)、壳长对肥满度直接作用最大(1.752)。形态性状与体质量、软体质量及肥满度的多元回归方程分别为Y=–46.359+0.288X1+1.723X2+0.640X3,R2=0.949;Y1=–6.607+0.301X1+0.157X2–0.161X3, R2=0.901; K=3.159+0.173X1+0.008X2–0.179X3, R2=0.072。壳宽是影响硬壳蛤体质量的主要因素,壳长是影响硬壳蛤软体质量的主要因素,各性状与肥满度回归关系不显著,个体间肥满度差异大。研究结果可为硬壳蛤选育及苗种繁育提供参考。  相似文献   

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Abstract

Three sets of bottom sediment samples, totalling 563, were collected in the Atchafalaya Bay, Louisiana. Cluster analysis was applied to each set of data based on grain‐size distribution. Comparison between resulting clusters and depositional environments indicates that the results of cluster analysis are sedimentologically meaningful and environmentally significant. A follow‐up discriminant analysis shows the stability of the classification system. The system then, in turn, can be used to classify sediments from unknown sources in the study area.  相似文献   

14.
武汉东湖富营养化的综合评价   总被引:29,自引:1,他引:29       下载免费PDF全文
蔡庆华 《海洋与湖沼》1993,24(4):335-339
兼顾富营养化评价和水生态系统常规监测,提出了以7种常见营养物(NO_3-N,NO_2-N,NH_4-N,TN,PO_4-P,TP,SiO_2)和浮游植物3个常用参数(日平均初级生产量P_G,生物量B,chla)为指标体系的湖泊营养类型评价标准;使用层次分析法,对上述10个因子作出权重分配,从而建立起评价湖泊富营养化程度的一种新方法。评价结果表明:尽管近年来东湖浮游植物的几项指标有所下降,但东湖富营养化程度奉有明显改变,  相似文献   

15.
李雪铭 《海洋科学》1998,22(1):55-58
在辽南大莲花泡全新世地层早、中、晚 3个沉积阶段中 Ca元素含量表现为低 -高 -低变化 ,Al,Mg,Cr,Ni,Cu,V,B,Mn等元素呈高 -低 -高分布。因子分析揭示出控制元素这种分布的主要因素是碎屑成因和生物成因。Ca元素的“稀释剂”作用改变了其他元素的实际含量 ,造成与干凉 -暖湿 -干凉的全新世气候变化不相匹配的假象。  相似文献   

16.
Salinity in a shallow estuary is affected by upland freshwater inputs (surface runoff, stream/canal flows, groundwater), atmospheric processes (precipitation, evaporation), marine connectivity, and wind patterns. In Everglades National Park (ENP) in South Florida, the unique Everglades ecosystem exists as an interconnected system of fresh, brackish, and salt water marshes, mangroves, and open water. For this effort a coastal aquifer conceptual model of the Everglades hydrologic system was used with traditional correlation and regression hydrologic techniques to create a series of multiple linear regression (MLR) salinity models from observed hydrologic, marine, and weather data. The 37 ENP MLR salinity models cover most of the estuarine areas of ENP and produce daily salinity simulations that are capable of estimating 65–80% of the daily variability in salinity depending upon the model. The Root Mean Squared Error is typically about 2–4 salinity units, and there is little bias in the predictions. However, the absolute error of a model prediction in the nearshore embayments and the mangrove zone of Florida Bay may be relatively large for a particular daily simulation during the seasonal transitions. Comparisons show that the models group regionally by similar independent variables and salinity regimes. The MLR salinity models have approximately the same expected range of simulation accuracy and error as higher spatial resolution salinity models.  相似文献   

17.
对粤西水东弧形海岸长时段重复测量海滩剖面的因子分析说明了各特征岸段剖面的主要地貌状态。频域分析反映了各岸段海滩体积的月周振动峰值和对波能的响应特征。实测海滩剖面波动过程的计算则指示了当前各剖面的蚀积状态。  相似文献   

18.
莱州湾游泳动物群落结构研究   总被引:1,自引:0,他引:1  
本文根据2010和2011年春季(5月)、夏季(8月)、秋季(10月)和冬季(12月)进行的8航次调查数据,研究了莱州湾游泳动物群落格局及其与环境因子关系。结果显示,调查共捕获游泳动物85种,2011年生物量略高于2010年;生物量季节间差别较大,各季节生物量排序为夏季、秋季、冬季和春季;不同年间相同季节生物量差异多不显著(秋季除外);除2010年春季外,其余季节均为鱼类生物量最高,甲壳类次之,头足类最低;从全年调查平均值来看,莱州湾西侧游泳动物生物量(60.2 kg/h)明显高于东侧(33.4 kg/h)。根据8航次31个主要种类生物量聚类分析,莱州湾20调查站位可划分为4组:组I由位于调查海域东南的3个站位组成,组II由位于调查海域东部及中部的8个站位组成,组III由调查海域西北部(黄河口南侧)的3个站位组成,组IV由西部6个站位组成。组I浮游植物丰度、浮游动物生物量、游泳动物生物量和游泳动物多样性指数在各组中均最低,而底栖动物生物量最高;组III和组IV的浮游植物丰度、浮游动物生物量以及游泳动物生物量高于组I和组II。ANOSIM分析表明,各聚类组间群落结构虽有不同,但差异并不显著。DCCA分析表明,温度、盐度、底栖动物生物量以及浮游植物丰度是影响游泳动物群落的重要因子。研究表明,目前莱州湾游泳动物群落总生物量处于较低水平,特别是春季生物量下降尤为严重;生物量的季节分布发生了较大的改变,春季生物量极低,夏季生物量相对较高;底层鱼类比例下降的趋势有所逆转,头足类比例明显增加。莱州湾游泳动物群落格局异质性较低,可能与莱州湾生境异质性低以及人类剧烈干扰密切相关。  相似文献   

19.
Tidal flooding and surface drainage patterns have often been used to describe mangrove species zonation. However, in mangrove forests exhibiting little topography, ambiguous species distributions and/or few species, such approaches are ineffective. We identified four physiognomic mangrove forest types (Riverine, Fringing, Overwash and Basin) at Coombabah Lake, a tidal lake in southeast Queensland, Australia and investigated tidal flooding patterns using synoptic surveys of tidal observations at the local Standard Port combined with local water depth observation. Subsequently three sub-types of the basin forest type were identified: (1) Deep Basin Forest with mature trees, ∼50 cm standing water and ∼3 tides per year; (2) Medium Depth Basin Forest with intermediate tree development, ∼15–30 cm standing water and 20–40 tides per year; and (3) Shallow Basin Forest with relatively recent mangrove establishment, 5–15 cm standing water and ∼80 tides per year. These three basin sub-types were found to flood at different tide heights with the Shallow Basin flooding for tides above mean high water springs and the Deep Basin flooding only for tide heights approaching the highest astronomical tide. We propose that these basin types represent a succession in mangrove forest development that corresponds with increasing water depth and tree maturation over time. The succession not only represents increasing age but also change in basin substrate composition. This is manifest as increasing pneumatophore density and an increasing area of basin surface occupied by contiguous pneumatophore cover. As a result, it seems that mangrove development is able to modify tidal flooding into the basin by increasingly impeding water movement.  相似文献   

20.
Goodnews Bay, southwest Alaska, is known for platinum (Pt) reserve that extends offshore in the Bering Sea. To assess the nearshore placer potential we first collated marine Pt concentrations available since 1960 in a geographic information system (GIS) database. Subsequently, in 2005, we collected 23 pipe dredge sediment samples and 26 vibracores from unexplored sites and analyzed them for Pt. This sampling was supplemented by magnetic (Sea Spy) and seismic (side scan, geoacoustic and datasonic bubble pulser) surveys. Integrating results of geospatial analysis of Pt concentrations with geophysical analysis using GIS techniques led to delineate four locations encouraging for further Pt exploration. Of these, two locations fall close to paleochannels and drowned ultramafic source, while the other two coincide with high energy environments in the Goodnews Bay and close to the Carter Bay.  相似文献   

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