Formation and Evolution of Ancient Lakes on South Coast Plain of Laizhou Bay

Based on the data of historical geography, the analysis of the stratigraphic section, and the textual research of place names and satellite photographic interpretations, the authors study the formation and evolution of ancient lakes on the south coast plain of Laizhou Bay where there were once three lakes: Judian Lake, Qingshuibo Lake and Biehua Lake. All the lakes formed 6000 years ago evolved from the lagoons near the estuary and went through two periods, the golden age in the Middle Holocene and the shrinking age in the Late Holocene. The disappearance of the lakes resulted from the drying climate, the migration of the river courses and the activities of human beings. Among the three reasons, the migration of the river courses is the main one.

A STUDY OF THE SURFACE EMERGING PALAEOCHANNELS ON THE SOUTH COAST PLAIN OF LAIZHOU BAY

By employing many methods including distinguishing the land maps, interpreting the aerophotoes and Satellite photographes, consulting historical documents, investigating ancient cultural relics, making investigations in the field, analysing the names and features of the place, and analysing the characteristics of the deposit, etc., a systematic study of the surface emerging palaeochannels on the South Coast Plain of Laizhou Bay has been made. Twenty five surface emerging palaeochannels were discovered and verified. According to the formation age, these palaeochannels were divided into two stages: six palaeochannels were formed in the Early and Middle Holocene, and nineteen palaeochannels were formed in the Late Holocene(the historical period). According to the landform features, the palaeochannels are divided into four categories: upland palaeochannel belts, strip shaped upland palaeochannels, trough shaped depression palaeochannels and ancient riverbeds. Among the four categories, the strip shaped upland palaeochannels are the main types. The swinging and movement of the channels helped the alluvial plains expand and cause the coastal ancient lakes to vanish in succession.

Analysis of wave shoaling and shore-breakers on a low tide terrace beach based on in-situ measurements at Xisha Bay on South China coast

Low tide terrace beach is a main beach type along South China coasts with strong tidal actions.How strong tides affect wave transformations on low tide terrace beach still remains unclear.In this study,in-situ measurements are conducted on the low terrace beach at Xisha Bay to provide quantitative descriptions of wave shoaling and shore-breaker phenomena under the tidal effects.It is found that wave breaking is unsaturated on the low tide terrace beach at Xisha Bay.Magnitudes of wave skewness and asymmetry increase as wave shoals and achieve the maximum value at the shore-breaker,and then decrease rapidly.Mean energy dissipation rates of shore-breakers are tide-modulated since the bottom slope changes at the shoreward boundary of wave propagation in a tidal cycle.The remaining wave energy flux at the initialization of the shore-breaker is 1%–12%of offshore wave energy flux,and the energy flux ratio decreases with increasing offshore wave heights.Wave attenuation at shore-breakers can be estimated directly from offshore wave conditions based on findings in this study,favoring designs of seawalls or beach nourishment projects.Field datasets on wave transformations can also be used for verifications of wave numerical models.

Thermodynamics and Microphysical Characteristics of an Extreme Rainfall Event Under the Influence of a Low-level Jet over the South China Coast

In this paper,the data of Automatic Weather Stations(AWSs),ERA5 reanalysis,sounding,wind profile radar,and dual-polarization radar are used to study an extreme rainfall event in the south China Coast on 11 to 12 May 2022 from the aspects of thermodynamics and microphysical characteristics under the influence of low-level jets(LLJs).Results show that:(1)The extreme rainfall event can be divided into two stages:the first stage(S1)from 0000 to 0600 LST on May 12 and the second stage(S2)from 0700 to 1700 LST on the same day.During S1,the rainfall is mainly caused by the upper-level shortwave trough and the boundary layer jet(BLJ),characterized by strong upward motion on the windward side of mountains.In S2,the combined influence of the BLJ and synoptic-system-related low-level jet(SLLJ)increases the vertical wind shear and vertical vorticity,strengthening the rainstorm.In combination with the effect of topography,a warm and humid southwest flow continuously transports water vapor to farther north,resulting in a significant increase in rainfall over the study area(on the terrain’s windward slope).From S1 to S2,the altitude of a divergence center in the upper air decreases obviously.(2)The rainfalls in the two stages are both associated with the mesoscale convergence line(MCL)on the surface,and the wind field from the mesoscale outflow boundary(MOB)in S1 is in the same direction as the environmental winds.Due to a small area of convergence that is left behind the MOB,convection moves eastward quickly and causes a short duration of heavy rainfall.In S2,the convergence along the MOB is enhanced,which strengthens the rainfall and leads to strong outflows,further enhancing the surface convergence near the MOB and forming a positive feedback mechanism.It results in a slow motion of convection and a long duration of heavy rainfall.(3)In terms of microphysics,the center of a strong echo in S1 is higher than in S2.The warm-rain process of the oceanic type characterizes both stages,but the convective intensity in S2 is significantly stronger than that in S1,featuring bigger drop sizes and lower concentrations.It is mainly due to the strengthening of LLJs,which makes small cloud droplets lift to melting levels,enhancing the ice phase process(riming process),producing large amounts of graupel particles and enhancing the melting and collision processes as they fall,resulting in the increase of liquid water content(LWC)and the formation of large raindrops near the surface.

Spring phytoplankton variability along a south coast of Sfax at the water-sediment interface(Tunisia,Eastern Mediterranean Sea)

Objective:To compare the composition of the phytoplankton classes during the two spring studies,to study whether the spatial distribution of the phytoplankton is stable or not between spring 2010 and spring 2011 and to estimate the abiotic factor that mostly affects the structure and the richness of phytoplankton.Methods:Phytoplankton sub-samples were counted under an inverted microscope using the Utermöhl method.Phytoplankton identification was made from morphological criteria after consulting various keys.Results:Results showed a significant difference from spring 2010 to spring 2011 regarding nitrate/phosphate ratio,with high value in spring 2010(30.19±25.70).Relatively low nitrate/phosphate ratio(1.13±0.53)during spring 2011 might result from phosphogypsum.Phytoplankton was characterised by the proliferation of Bacillariophyceae(46%–78%of the total microphytoplankton)and by the large number of Euglenophyceae.Thirty two Bacillariophyceae species were identified at every station,represented essentially by Amphora sp.,Navicula sp.,Coscinodiscus sp.and Grammatophora sp.The results advise that Bacillariophyceae are usually adapted to particular ecological environment.Conclusions:This study shows that hydrological conditions in the south coast of Sfax present a high spatial and seasonal variability.The phytoplankton community distribution showed clear variations along the coastal stations during a spring cruises conducted in May 2010 and May 2011.The phytoplankton community found along the coast was dominated by opportunistic Bacillariophyceae species.

Coastal dune rock development and Holocene climate changes in South China

Coastal dune rocks in China are eolian sands cemented by calcium carbonate under subaerial conditions, widely distributing on the tropical and subtropical coasts of South China. Particular temperature and precipitation as well as local wave and landform conditions are required for the formation of the dune rocks. A correspondence was found between Holocene environmental changes and coastal dune rock development by comparing the features of the sea-level and climate changes in the Holocene period with the ages, scales, and cementation of the dune rocks on the South China coasts. The findings provide well grounded explanation for some problems unresolved in the past researches on the coastal dune rock in South China： （1） There were no dune rocks with ages older than 6000 years in South China because the dune rocks formed before 6000 a BP were covered by the sea water that rose in the later period; （2） the dune rocks with ages of around 3000 a BP were widely found in South China today because the coastal dunes were cumulated on a large scale at that time as a result of temperature falling after the end of Megathermal; （3） Medieval Warm Period was the main period for the eolian dunes to be cemented into the coastal dune rocks in South China; （4） lack of dune rocks of younger than 1000 a BP was accounted for by that the climate conditions in recent one thousand years were not suitable for the cementation.

Study of the marine (saltwater) transgression in the palaeo-channels on the south coast plain of Laizhou Bay

The palaeochannels in the studied region are divided into four stages by such methods as 14C dating. Marine (saltwater) transgression in the palaeochannels has been studied as a focal point. Palaeochannels are the main passageway through which the seawater (saltwater) transgresses. The seawater (saltwater) transgresses at a high speed, by many means and in a changeable dynamic state.

Preliminary research on sea-level changes of the South China coast since late Epipleistocene

Several views on sea-level changes of the South China coast are briefly introduced in this paper. On the basis of 236 samples whose ages are determined by 14C chronological method and their sites are corrected with ancient water depth and crustal deformation, a basic model about sea-level changes of the South China coast since late Epipleistocene is set up. This model basically accords with the general cognitions of predecessors, i. e. it not only represents the common characteristics of sea-level changes of the East China coast but has some features of the South China coast itself. In general, this model is relatively close to the Fairbridge's curve, indicating that the sea-level undulations exist since 6 ka ago but the ranges of undulations are slightly larger than those of Fairbridge's curve.

Mesoscale wind stress-SST coupling induced feedback to the ocean in the western coast of South America

The feedback induced by mesoscale wind stress-SST coupling to the ocean in the western coast of South America was studied using the Regional Ocean Modeling System(ROMS).To represent the feedback,an empirical mesoscale wind stress perturbation model was constructed from satellite observations,and was incorporated into the ocean model.Comparing two experiments with and without the mesoscale wind stress-SST coupling,it was found that SST in the mesoscale coupling experiment was reduced in the western coast of South America,with the maximum values of 0.5℃in the Peru Sea and 0.7℃in the Chile Sea.A mixed layer heat budget analysis indicates that horizontal advection is the main term that explains the reduction in SST.Specifically,the feedback induced by mesoscale wind stress-SST coupling to the ocean can enhance vertical velocity in the nearshore area through the Ekman pumping,which brings subsurface cold water to the sea surface.These results indicate that the feedback due to the mesoscale wind stress-SST coupling to the ocean has the potential for reducing the warm SST bias often seen in the large-scale climate model simulations in this region.

A study on Holocene aeolian shell-clastic sandstonesalong the coasts of South China andthe analysis of its formation

The Holocene aeolian shell-clastic sandstones at 13 places along the coasts of Fujian, Guangdong and Hainan Provinces are studied in the following respects; describing their features from both macroscopic and microscopic views, listing their distributions, altitudes and forming ages, and discussing the nomenclatures of this kind of rock and its differences from beach rock.

海洋空间的“领土化”构建与实践 ——以美国在南海地区的干涉行动为例

随着海洋与人类的联系越来越密切,控制人类海上活动的必要性,令海洋空间的“领土化”成为难以避免的趋势。主流话语开始从将海洋描述为无主之地,变成倾向于为扩大公共权力对海域控制的做法辩护,为海上力量投送和海域管控编织正当理由。由此,产生了一定的海洋空间“领土化”,国家从规范功能的角度逐渐控制海洋空间,将公共权力投射至领海和管辖水域外的海域。塑造符合自身利益需求的地区规范秩序,并在实践上强化地区军事力量投送,这两种海洋空间“领土化”扩张方式,鲜明地体现在美国在南海地区的干涉行动中。中国需在南海促进建设更有效的海洋治理体系,扩大行为规范塑造和海洋新秩序建设上的话语权,更好地维护国家海洋安全和发展利益。

Temperature variability caused by internal tides in the coastal waters of east coast of Peninsular Malaysia

The effects of tidal currents(i.e., barotropic and internal tides) are important in the biogeochemistry of a coastal shelf sea. The high-frequency of currents and near-bottom temperatures collected in three consecutive southwest monsoon seasons(May, June, July and August of 2013 until 2015) is presented to reveal the role of the tidal currents to the temperature variability in the coastal shelf sea of the east coast of Peninsular Malaysia(ECPM),south of the South China Sea(SCS). The results of a spectral density and harmonic analysis demonstrate that the near-bottom temperature variability and the tidal currents are influenced by diurnal(O_1 and K_1) and semidiurnal(M_2) tidal currents. The spectral density of residual currents(detided data) at 5, 10 and 16 m depth also shows significant peaks at the diurnal tidal frequency(K_1) and small peaks at the semidiurnal tidal frequency(M_2)indicating the existence of internal tides. The result of the horizontal kinetic energy(HKE) shows a strong intermittent energy of internal tides in the ECPM with the strongest energy is found at 16 m depth during a sporadic cooling event in June and July. A high horizontal cross-shore heat flux(16 m) also indicates strong intrusions of cooler water into the ECPM in June and July. During the short duration of cold pulse water observed in June and July, a cross-wavelet analysis also reveals the strong relationship between the near-bottom temperatures and the internal tidal currents at the diurnal tidal frequency. The intrusion of this cooler water is probably related to the monsoon-induced upwelling in June. It is loosely interpreted that the interaction between the strong barotropic tides and the steep slope in the central basin of the SCS under the stratified condition in southwest monsoon has generated these internal tides. The dissipation of internal tides from the slope area probably has driven the cold-upwelled water into the ECPM coastal shelf sea when the upwelling intensity is the highest in June and July.

华南沿海海草床分布区大型底栖动物群落特征初探

为探究华南沿海海草床大型底栖动物群落特征、地区差异及其与海草群落间的关系,2020年在华南沿海12个海草床区域开展了大型底栖动物调查。共布设33个调查断面99个站位,在主要群落参数的基础上,运用相关性分析和聚类分析、nMDS排序、相似性百分比分析等群落生态学统计方法分析了底栖动物群落特征及其与海草群落的关系。共鉴定出大型底栖动物9大门类199种,其中,软体动物种类最多,占总种类数的39.7%。各区域底栖动物的平均栖息密度为155.7 ind/m2,青葛—龙湾(琼海)的平均栖息密度最低,珍珠湾(防城港)的平均栖息密度最高;平均生物量为118.36 g/m2,最低值出现在义丰溪(汕头),最高值出现在珍珠湾。各区域底栖动物的优势种以潮间带泥沙滩常见腹足类、双壳类和多毛类为主;底栖动物的种类多样性指数(H′)平均值为1.12,最低值出现在唐家湾(珠海),最高值出现在铁山港(北海);各调查区域底栖动物主要群落参数大致呈现“北部湾>海南沿岸>珠江口及粤东”的规律。华南沿海海草床分布区大型底栖动物群落的区域性特征较为明显,地理位置相近的海草床底栖动物群落特征相似性程度较高。海草密度越大,总生物量越高,越有利于底栖动物的种类多样性指数维持在更高水平。以大、中型海草为主的海草床,相较于面积小,以小型海草为主的海草床,其区域内的大型底栖动物群落结构更为复杂。

莱州湾南岸土壤盐碱程度与养分含量空间变异

【目的】探究莱州湾南岸土壤可溶性盐含量、pH值和养分的空间分布特征,为我国北方滨海盐渍土区脆弱生境生态保护与修复提供科学依据。【方法】以莱州湾南部海岸线以南30 km的区域为研究对象,基于3 km距离的网格化布点法采集313个样点0~20、20~40、40~60 cm深度的土壤样品,经室内测定结合地统计学原理与地理信息系统等方法,揭示不同土层可溶性盐含量、pH值及表层土壤各养分指标的空间变异性特征。【结果】1)研究区域0~20、20~40、40~60 cm土层可溶性盐含量分别介于0.19~8.44、0.14~9.86、0.18~10.61 g∙kg^(−1)之间,各土层平均土壤可溶性盐含量分别为1.23±1.65、1.42±1.73、1.48±1.72 g∙kg^(−1),盐渍化等级以非盐渍化土为主,盐渍化类型以硫酸盐−氯化物型及氯化物−硫酸盐型为主,土壤含盐量随土层深度增加而增加。各土层可溶性盐含量空间分布不均,0~20 cm土层土壤盐分呈中等程度的空间自相关性,20~40 cm和40~60 cm土层盐分空间自相关性较强。2)研究区域0~20、20~40、40~60 cm土层土壤pH值分别介于7.04~9.38、7.04~9.66、7.08~9.79之间,各土层平均土壤pH值分别为8.17±0.46、8.39±0.47和8.46±0.46,整体以非碱性等级为主;0~20 cm土层pH值呈中等程度的空间自相关特征,20~40 cm和40~60 cm土层pH值空间自相关性较强。3)研究区域表层土壤有机质、全磷和全钾含量介于0.28~30.29、0.20~1.29、15.44~23.01 g∙kg^(−1)之间,平均含量分别为9.70±6.50、0.59±0.21和19.21±1.31 g∙kg^(−1);有效氮和速效钾的含量介于1.33~66.72mg∙kg^(−1)和24.90~248.20 mg∙kg^(−1)之间,平均含量分别为12.67±9.62mg∙kg^(−1)和94.64±45.60 mg∙kg^(−1)。土壤有机质和速效钾含量呈由海到陆沿平行于海岸线的方向带状增加的分布趋势,空间自相关性较强。有效氮、全磷、全钾空间分布不均,呈中等程度的空间自相关特征。【结论】莱州湾南岸土壤盐碱程度和养分含量总体呈较低水平且空间分布不均,各指标空间变异在不同程度上受到结构性因素与随机性因素的共同影响,人为活动、土壤质地与植被生长状况是莱州湾南岸土壤盐碱与养分空间变异的主控因素。本研究可为我国陆地生态系统脆弱生境生态保护与精准修复、北方滨海盐渍土科学管理与利用、边际土地产能提升与固碳增汇等工作提供理论依据。

渤海南岸地区早期盐业生产原料、淋卤和煮盐工具问题

渤海南岸地区在晚商至西周早期、东周、魏晋、隋唐、蒙元时期盐业生产原料使用浓度较大的地下卤水,不存在采用淋灰取卤方式提高卤水浓度,使用的煮盐工具多为器腹较深的陶器和金属器。煮盐工具在盐灶上的摆放方式尤其是在晚商至西周、东周时期存在较大差异。

莱州湾南岸海岸侵蚀过程与原因研究

采用历史资料对比分析的方法，对莱州湾南岸1958-2004年的海岸侵蚀进行了研究。结果表明，1958-1984年，莱州湾南岸岸线平均侵蚀后退速率为27m／a，0m等深线后退速率为27～65m／a，岸滩平均蚀低速率为2．1cm／a。1984-2004年，莱州湾南岸岸线位置基本无变化，岸滩平均蚀低速率为1.04cm／a，水深5m以浅的区域表层沉积物变粗。海面相对上升、入海泥沙量减少和风暴潮是研究区海岸侵蚀主要原因，三者对海岸侵蚀影响权重比为3：5：2。

莱州湾南岸平原古湖泊的形成与演变

运用查阅历史文献、地层剖面分析、地名考证、卫片解译等多种方法确证了莱州湾南岸古湖泊的存在 ,同时研究了它的形成与演变过程。莱州湾南岸有巨淀湖、黑冢泊、别画湖等古湖泊 ,它们形成于距今约 6 0 0 0年以前 ,系由河口湾泻湖演变而成。该区古湖泊经历了中全新世全盛期和晚全新世收缩期两个阶段。湖泊消亡的原因是气候变干、河道迁移、人类活动影响等 ,其中河道迁移是最主要原因。

杭州湾南岸生态系统服务功能及其经济价值研究

生态系统服务功能是生态系统提供的商品和服务,是人类生存发展的物质基础和基本条件。该文应用生态学、生态经济学方法及Costanza等的研究成果,结合杭州湾南岸生态系统的自然和社会经济特征的分析,初步估算出2000年杭州湾南岸生态系统服务功能的总价值为91 1亿元,其中间接经济价值是直接经济价值的5 85倍,并对各种生态系统类型的服务价值构成进行了讨论。

杭州湾南岸土壤有机碳空间异质性研究

应用地统计学与地理信息系统相结合的方法,研究了杭州湾南岸慈溪市域内不同土层(0～20、20～40、40～60、60～80、80～100、0～100 cm)的土壤有机碳含量空间变异特征。结果表明:研究区各土层土壤有机碳平均含量变化范围为3.49～7.95 g kg-1,变异系数介于54.51%～67.34%之间,属中等程度变异;地统计分析得出块金效应变化范围为0.141～0.372,表现为较强空间自相关性;自表层至底层最优半方差模型依次为高斯、指数、指数、高斯和球状模型;Kriging插值结果显示各土层土壤有机碳含量自滩涂向内陆呈递增趋势,其中0～20 cm土层土壤有机碳含量呈平行于海岸线的带状分布;土壤有机碳含量随剖面深度增加呈递减规律;不同土地利用方式和不同围垦时期均增加了土壤有机碳的空间变异性。从研究结果看,慈溪市土壤有机碳空间异质性主要由结构性因素引起,研究结果可为了解杭州湾南岸土壤有机碳分布特征提供参考。

渤海莱州湾南岸第四纪地下卤水演化的地球化学模拟

渤海莱州湾南岸地区赋存有大量的地下卤水,许多研究者认为这些卤水是第四纪地质历史时期古海水经强烈蒸发浓缩后埋藏而成的。运用反向地球化学模拟理论,选用美国地质调查局(USGS)提供的PHREEQC(1997)地球化学模拟软件,对莱州湾南岸昌邑廒里501孔各层卤水的水化学演化过程进行模拟。研究结果表明,该地区的地下卤水是由古海水经强烈蒸发浓缩后被沉积物埋藏,并在赋存过程中发生水 岩相互作用,使地下水出现方解石、石膏及CO2气体的过饱和析出,并伴随与沉积物发生K+、Na+、Mg2+、Ca2+之间的阳离子交换反应。其中的浅层地下卤水还受到地表盐场析盐后排放卤水的侵染。