围垦工程影响下的淤涨型潮滩演化:以江苏弶港潮滩为例

通过对受到围垦工程影响的江苏弶港海岸两条潮滩剖面的多期高精度实测高程及沉积物粒度数据进行分析,探讨淤涨型潮滩剖面对围垦工程的响应特征及剖面演化模式。结果表明,在物源充足的淤涨型潮滩围垦,可导致沉积物在围垦堤附近海域快速堆积、沉积物粒径变细;离海堤越远,沉积速率及沉积物粒度参数的变化越不显著。围垦堤附近海域是潮滩低能区,沉积物在此汇聚,造成潮滩剖面凸点的向岸迁移及双凸型剖面的塑造。另外,大型潮沟及其迁移也是影响剖面发育的重要因素。未来需结合海平面变化,研究围垦背景下的长周期潮滩演化趋势。     

风暴对滨海湿地潮沟水沙输运的影响——以长江口崇明东滩为例

为了探知风暴事件对滨海湿地潮沟水沙输运的影响,分别于平静天气和风暴天气("摩羯"和"温比亚"台风)条件下,在崇明东滩一典型潮沟进行了现场水沙数据观测。结果表明:台风期间近岸平均风速较平静天气增大3～4倍,有效波高增大7～15倍,盐沼前缘光滩和潮沟遭受强烈侵蚀,潮滩表层沉积物粗化1～2.1倍,水体悬沙浓度增大3～11倍,潮沟潮周期单宽泥沙输运通量增大4～33倍,单宽泥沙净输沙量增大8～17倍。风暴天气下,潮沟水沙输运呈现"大进大出"的特点,在盐沼潮滩内受盐沼植被消波、缓流和捕沙作用下,潮周期内单宽泥沙净通量指向盐沼潮滩,促进了盐沼滩内部泥沙的淤积。     

长江口崇明东滩冲淤演变分析

通过对崇明东滩水文、泥沙、地形等资料的分析,阐述1983-2003年崇明东滩冲淤演变过程. 1.1983-2001年,崇明东滩淤涨延伸较快,0m以上各等高线大幅度向外扩展,沿正东向年均外移228~279m不等.潮滩面积稳定增长,3.5m以上面积增加最多,达65.2km2,0m以上面积共增加8.4km2.滩面淤高迅速,尤其是高潮滩,且有随高程的降低,淤高速率下降的趋势.2. 2003年与2001年相比,崇明东滩0m以上面积增加4.2km2,2.0m以上面积减少0.8 km2,3.0m以上面积年均增长率下降.3.人类活动(如围垦)对崇明东滩的演变产生重要影响.流域来沙量大幅减少对潮滩演变的影响有待于进一步研究.     

河口潮滩地貌和沉积物对人类工程的响应特征

河口潮滩受径潮流的共同作用,在自然环境与人类活动的影响下处于不断的动态调整中,其中大型人类工程往往对其短期地貌变化和沉积物特征产生巨大影响。2013年底至2014年5月,长江口崇明东滩北部开展大规模互花米草治理工程,本文基于地面三维激光扫描技术、植被点云数据滤除算法、沉积物取样以及室内粒度分析等手段,对比了工程前后潮滩地貌与沉积物特征。研究发现:（1）完工后研究区域靠海及南侧区域出现明显冲刷,北侧虽出现淤积,但整个区域平均冲刷幅度仍达4 cm;（2）工程前研究区域沉积物平均中值粒径为29 μm,工程完工后沉积物平均中值粒径则增大到38 μm;（3）工程完工后沉积物靠海及南侧区域明显粗化,北侧沉积物则变细。结果表明,围垦工程会造成邻近潮滩大幅冲刷以及表层沉积物粗化,但潮滩不同区域地貌和沉积物特征对工程的响应仍存在空间差异性。研究揭示尽管河口潮滩长期演变过程受流域来沙条件影响,但围垦工程等局部影响因素会短期内显著改变潮滩动力地貌过程。     

潮沟系统水沙输运研究——以长江口崇明东滩为例

本研究以崇明东滩2015年4月实测潮间带水沙数据为基础,分析了潮沟、盐沼及光滩的水沙特征,重点研究了潮沟系统及邻近潮滩潮周期内悬沙通量情况。结果表明:（1）潮沟表层沉积物比潮滩细,二者平均中值粒径分别为21.7 μm和33.0 μm,悬沙粒径由海向陆逐渐变小;（2）大、小潮沟潮周期内潮流均以往复流为主,垂向平均流速分别为15.4 cm/s和34.6 cm/s;盐沼界和光滩则以旋转流为主,平均流速分别为11.3 cm/s和28.9 cm/s;（3）潮沟中的高悬沙浓度出现在涨潮初期,最大可达7.5 kg/m3,而潮滩高悬沙浓度则出现在潮落潮中期和高水位时刻;大、小潮沟和盐沼界站涨潮阶段平均悬沙浓度大于落潮阶段,光滩站则相反。潮沟悬沙主要来自邻近水域,而潮滩悬沙则与滩面表层沉积物密切相关;（4）潮沟在潮周期内净输沙方向均指向滩地,大潮沟潮周期单宽净输沙量可达4.0 t/m;盐沼界处垂直岸线和沿岸输沙强度相近,净输沙由海向陆,潮周期离岸输沙强度为1.0 t/m;光滩沿岸输沙强度远大于垂直岸线输沙,光滩净输沙由陆向海。研究揭示了潮间带潮沟系统的强供沙能力以及研究区域光滩冲蚀,盐沼植被带淤积的动力地貌过程。     

围垦工程影响下的江苏弶港潮滩剖面的演化机制

以江苏弶港潮滩为典型研究区,基于2007—2012年在潮滩及条子泥匡围工程实施期间采集的9条潮滩断面高程数据,建立潮滩剖面形态的二次函数统计模型,并结合同步采集的表层沉积物粒度数据,对围垦影响下的潮滩剖面演化机制进行了探讨。结果表明,受围垦工程影响较小的北部潮间带上部的淤积强度要大于潮间带中下部淤积强度,潮滩剖面呈上凹型;正在实施的围垦工程加剧了垦区内潮滩的淤积,尤其在下部呈现高强度淤积而造成垦区内潮滩剖面的上凸趋势减缓,剖面曲率减小。此外,由于垦区内逐渐失去潮汐水动力作用,与附近非垦区类似潮滩带相比,垦区内滩面沉积物呈细化趋势。围垦工程在潮间带中下部筑堤坝,对涨潮水体有阻滞作用,使得外海带来的细颗粒沉积物在围堤外侧快速堆积,造成原潮间带下部快速淤高,形成垦区外向海侧微下凹的潮滩剖面形态。     

深圳龙岐湾海滩资源调查与开发建议

文章基于2022年春、秋季开展的龙岐湾沙滩资源调查数据,分析较场尾沙滩、大塘角沙滩、黄泥湾沙滩和桔钓沙沙滩的剖面特征、沉积物粒径和裂流发生情况。研究结果表明：4处沙滩剖面的坡度秋缓春陡,剖面受风浪和潮汐直接作用时坡度变化大,受遮蔽时坡度变化小,整体呈冬春淤积、夏秋侵蚀;沙滩沉积物以中砂、粗砂和砾石为主,粒径变化不大;沙滩均无明显裂流发生,为低风险等级。建议开发沙滩旅游应考虑季节性的补沙方案,开展围垦养殖和海岸工程应注意削弱ESE向和SE向的波浪作用。     

长江口湿地沉积物中的氮、磷与重金属

研究了总氮NT、总磷Pt、重金属Cu,Zn,Pb和Cd在崇明东滩湿地沉积物中的分布与累积特征。结果表明,NT和重金属表现为：芦苇带〉互花米草带〉海三棱镳草带〉光滩,即从光滩至芦苇带,从南部至北部,NT和重金属的质量分数呈现逐步增加的趋势。由于高潮带以细颗粒为主,有机质含量较高,因此NT和重金属表现出相应的富集;而沉积物PT在各个湖带呈均匀分布,这主要与沉积物中磷的化学形态组成有关。与上海南岸潮滩湿地和世界其他河口湿地相比,东滩湿地沉积物中重金属的质量分数相对较低,表明它是一块保存较为完好未受到污染的天然湿地,这主要与长江径流对污染物的稀释作用有关。     

长江口崇明东滩不同植被带沉积速率研究

利用2007年丰水期、枯水期在崇明东滩芦苇带、藨草带和光滩采集的6根沉积物柱状样,研究了沉积物的粒度特征和过剩的210Pb和228Th及7Be活度的垂向分布特征,探讨了由陆地向海洋不同植被间的沉积物粒度变化规律。依据恒定比活度沉积速率模型,估算了不同时间尺度的崇明东滩芦苇带、藨草带和光滩的表观沉积速率。结果表明:3种核素示踪的崇明东滩的表观沉积速率都随潮滩植被的不同从陆到海方向逐渐降低,同时依过剩的210Pb和228Th,7Be的次序而增大。由过剩的210Pb和228Th计算的夏季沉积速率比冬季的稍高,而由7Be计算的夏季表观沉积速率则明显高于冬季的。结合沉积物粒度的时空分布和这些核素的大气通量,对利用这些核素测定潮滩沉积速率的影响因素进行了探讨。     

长江口九段沙岸滩的短周期地貌动力过程

根据2006年5～10月(洪季)长江口九段沙上沙两固定断面的逐月滩面高程测量及表层沉积物的粒度分析结果,尤其是应用"碧利斯"台风前后的实测水文地貌资料,结合同期表层悬沙浓度的逐日观测资料,开展了九段沙岸滩地貌动力过程及沉积物对台风响应的研究.结果显示,长江口九段沙上沙东南岸滩演变表现为"岸冲滩淤"的变化规律,即堤岸呈现冲蚀,潮滩在冲淤变化中总体趋于淤积.2006年"碧利斯"台风期间,九段沙上沙波高达2.56 m,增水1 m多,强浪伴随增水,导致滩面平均蚀低6.4 cm,最大蚀深为20.2 cm.台风作用造成滩面冲刷,沉积物粗化,台风过后滩面迅速回淤,粒径变细.这充分表明,暴风浪是引起九段沙上沙岸滩及其沉积物短期突变的重要动力因素.河口潮滩冲淤对流域水沙变化有较敏感响应,长江来水来沙变化是制约潮滩季节性冲淤演化的重要因子.岸滩短期变化主要原因在于波浪掀沙和潮流输沙的联合作用.由于潮流和潮位位相不一致,造成涨潮流携高含沙量水体上滩落淤,落潮流携低含沙量滩水归槽,涨潮输沙淤滩被波浪刷滩所掩盖,如此往复,潮滩淤积.最后分析了上沙抛石堤的护岸保滩作用及不足之处,并提出了加固措施.现有的上沙抛石堤能防御常浪冲刷,受台风浪袭击时仅能抵御堤岸蚀退,石堤自身的毁坏难以避免,需经常修护;在潮沟口应设涵洞;基于台风浪的巨大能量,抛石堤块石需增大增重.该研究结果可为河口湿地的保护和建设提供科学依据.     

中国鱼类名录Ⅻ--鳚亚目、(鱼衔)亚目、喉盘鱼亚目、鰕虎鱼亚目、微体鱼亚目、刺尾鱼亚目、带鱼亚目、鲭亚目、鲳亚目、金枪鱼亚目、攀鲈亚目、刺鳅亚目

鳚亚目 4 科 33 属 95 种，鰕虎鱼亚目 5 科 98 属 259 种，刺尾鱼亚目 5 科 11 属 65 种，鲈形目 19亚目 104 科 535 属 1799 种。     

Distribution, abundance, and growth of larval tautog, Tautoga onitis, in Buzzards Bay, Massachusetts, USA

Tautog, Tautoga onitis, is an abundant species of fish in estuaries of the northeastern United States. Planktonic tautog larvae are abundant in summer in these estuaries, but there is little information on rates of growth of tautog larvae feeding on natural assemblages of food in the plankton. We examined abundance and growth of larval tautog and environmental factors during weekly sampling at three sites along a nearshore‐to‐offshore transect in Buzzards Bay, Massachusetts, USA during summer 1994. This is the first study of a robust sample size (336 larvae) to estimate growth rates of field‐caught planktonic tautog larvae feeding on natural diets, using the otolith daily‐growth‐increment method. The study was over the entire summer period when tautog larvae were in the plankton. The sampling sites contrasted in several environmental variables including temperature, dissolved oxygen (DO), and chlorophyll a concentration. There was a temporal progression in the abundance of tautog larvae over the summer, in relation to location and temperature. Tautog larvae were first present nearshore, with a pronounced peak in abundance occurring at the nearshore sites during the last 2 weeks in June. Larvae were absent at this time further offshore. From late June through August, larval abundance progressively decreased nearshore, but increased offshore although never approaching the abundance levels observed at the nearshore sites. The distribution and abundance of tautog larvae appeared to be related to a nearshore‐to‐offshore seasonal warming trend and a nearshore decrease in DO. Otoliths from 336 larvae ranging from 2.3 to 7.7 mm standard length had otolith increment counts ranging from 0 to 19 increments. Growth of larval tautog was estimated at 0.23 mm·day^?1, and length of larvae prior to first increment formation was estimated at 2.8 mm indicating that first increment formation occurs 3–4 days after hatching at 2.2 mm. Despite spatial and temporal differences in environmental factors, there were no significant differences in growth rates at any of three given sites over time, or between sites. Because larval presence only occurred at a narrow range of temperature (17–23.5 °C) and DO (6.5–9.3 mg·l^?1), in situ differences in growth did not appear to be because of differences in larval distribution and abundance patterns relative to these parameters.     

The distribution of Mn,Fe, Cu,Ni, Co,Ga, Cr,V, Ba,Sr, Sn,Zn, and Pb,in some soil-sized particulates from the lower troposphere over the world ocean

Soil-sized particulates have been collected on board ship by a mesh technique from the lower troposphere of the North, Equatorial and South Atlantic Ocean, northern and southern Indian Ocean, South and East China Sea and various coastal localities.Spectrographic analysis reveals that, on average, the particulates have concentrations of Mn, Ni, Co, Ga, Cr, V, Ba, and Sr which are of the same order of magnitude as those in average crustal material. In contrast, the average concentrations of Pb, Sn, and Zn are one order of magnitude higher than those in average crustal material.Within this “world-wide” average there are significant geographical variations in the distributions of Pb, Sn, and Zn which may be related to anthropogenic sources.On the basis of trace-element distributions lower tropospheric soil-sized marine particulates have been divided into four genetic components; local, zonal, inter-zonal, and global. The proportions of these components vary geographically, and each component may have both a natural and an anthropogenic fraction.     

The behavior of Zn,Cd, Cu,Ni, Co,Fe, and Mn in anoxic baltic waters

In June 1981, dissolved Zn, Cd, Cu, Ni, Co, Fe, and Mn were determined from two detailed profiles in anoxic Baltic waters (with extra data for Fe and Mn from August 1979). Dramatic changes across the O₂H₂S interface occur in the abundances of Cu, Co, Fe, and Mn (by factors of ?100). The concentrations of Zn, Cd, and Ni at the redox front decrease by factors between 3 to 5.Equilibrium calculations are presented for varying concentrations of hydrogen sulfide and compared with the field data. The study strongly supports the assumption that the solubility of Zn, Cd, Cu, and Ni is greatly enhanced and controlled by the formation of bisulfide and(or) polysulfide complexes. Differences between predicted and measured concentrations of these elements are mainly evident at lower ΣH₂S concentrations.Cobalt proved to be very mobile in anoxic regions, and the results indicate that the concentrations are limited by CoS precipitation. The iron (Fe²⁺) and manganese (Mn²⁺) distribution in sulfide-containing waters is controlled by total flux from sediment-water interfaces rather than by equilibrium concentrations of their solid phases (FeS and MnCO₃). The concentrations of these metals are therefore expected to increase with prolonged stagnation periods in the basin.     

Destruction of Atmospheric Ozone in Ox,HOx, NOx,ClOx, BrOx,and IOx Catalytic Cycles

Izvestiya, Atmospheric and Oceanic Physics - Data on the relative contribution of the Ox, HOx, NOx, ClOx, BrOx, and IOx catalytic cycles to atmospheric ozone destruction are given for June and...     

Submerged vegetation of Lakes Sumner,Marion, Katrine,Taylor, and Sheppard in Canterbury,New Zealand

The submerged vegetation of Lakes Sumner, Marion, Katrine, Taylor, and Sheppard was surveyed in May 1987. These high‐altitude lakes lie at c. 600 m a.s.l., within the largely unmodified upper Hurunui catchment. Submerged vegetation was diverse and included numerous short shallow‐water species, dense swards of Isoetes alpinus, low covers of taller native vascular plants, and charophyte meadows beyond the depth limit of vascular plants to a maximum of 15 m. A sparse deepwater bryophyte community was observed from 11 to 32 m depth in Lake Sumner. Displacement of native vegetation by dense growths of the adventive oxygen weed Elodea canadensis over mid‐depths of 3–6 m was noted in all lakes, except Lake Marion.     

Distribution and stoichiometry of Al,Mn, Fe,Co, Ni,Cu, Zn,Cd, and Pb in seawater around the Juan de Fuca Ridge

A central theme of the ongoing GEOTRACES program is to improve the understanding of processes occurring at ocean interfaces with continents, sediments, and ocean crust. In this context, we studied the distributions of Al, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb around the Juan de Fuca Ridge (JdFR) in total dissolvable (td), dissolved (d), and labile particulate (lp) fractions, which represent a fraction in unfiltered samples, filtered samples through an AcroPak capsule filter, and the difference between td and d, respectively. Al and Fe were dominated by lp-species, while Ni, Zn, and Cd were dominated by d-species with undetectable amounts of lp-species. Major findings in this study are as follows: (1) The continental margin (CM) provided large sources of Al, Mn, Fe, and Co from the surface to ~2000 m in depth. The supply from CM caused high surface concentrations of dMn and dCo, a subsurface (100–300 m depth) maximum of dCo, and intermediate (500–2000 m depth) maxima of lpAl and lpFe. The supply of dFe from CM was ~10 times that from the high-temperature hydrothermal activity at station BD21, which is located at ~3 km from the Middle Valley venting site and ~ 200 km from Vancouver Island. (2) DPb was maximum at the top layer of North Pacific Intermediate Water, probably owing to isopycnal transport of anthropogenic Pb via advection of subducted surface waters. Although dCo and dPb had different sources in the upper water, they showed a strong linearity below 300 m (r ² = 0.95, n = 38), indicating concurrent scavenging. (3) A high-temperature hydrothermal plume occurred at a depth of 2300 m at BD21, accounting for maxima of dAl, dMn, dFe, lpCu, and lpPb and a minimum of dCu. (4) Strong bottom maxima of lpAl, lpMn, lpFe, lpCo, and lpPb occurred above the abyssal plain at the western foot of the JdFR, indicating resuspension of sediments. However, bottom maxima of d-species were apparent only for dAl and dCu.     

Identification,characterization, and statistical analysis of mudstone aggregate clasts,Cretaceous Carlile Formation,Central Alberta,Canada

While clastic mudstones and shale were traditionally interpreted to have been deposited in quiet water settings, recent flume experiments and studies have shown that mud can be transported in and deposited by traction currents as migrating ripples of mud aggregates. Despite these recent advances, mud aggregates have rarely been adequately described in the rock record.These mud aggregates and the sedimentary structures they form in mudstone successions are difficult to observe in the rock record due to compaction, which often obliterates the aggregates and flattens bedforms. This paper documents unambiguously identifiable sand sized mudstone aggregates in thin sections and SEM, transported in traction, and deposited in a series of prograding clinothems. These aggregates were sufficiently indurated to locally preserve shelter porosity, significantly improving the hydrocarbon reservoir properties.Grain size analysis of the aggregates was performed on thin sections, as well as disaggregated samples measured by a laser diffraction grain size analyzer for comparison. These analyses showed that sand sized aggregates often comprise more than half of the sediment volume. While the clay-rich composition of the Carlile Formation would suggest that it is a mudstone, statistical analysis of these grain size measurements show that it could alternatively be described as a silty sandstone. These findings potentially change how we think about mudstone classification, fine-grained sedimentation, and mudstone dominated petroleum reservoirs.     

Cross-Calibration and Long-Term Monitoring of the Microwave Radiometers of ERS, TOPEX, GFO, Jason, and Envisat

The radiometers on board the satellites ERS-1, TOPEX/Poseidon, ERS-2, GFO, Jason-1, and Envisat measure brightness temperatures at two or three different frequencies to determine the total columnal water vapor content and wet tropospheric path delay, a major correction to the altimeter range measurements. In order to asses the long-term stability of the path delay, the radiometers are calibrated against vicarious cold and hot references, against each other, and against several atmospheric models. Four of these radiometers exhibit significant drifts in at least one of the channels, resulting in yet unmodeled errors in path delay of up to 1 mm/year, thus limiting the accuracy at which global sea level rise can be inferred from the altimeter range measurements.