Announcement

Cadmium, lead and copper have been determined in both dissolved and particulate phases for 130 surface-water samples from the coastal zone of Scotland and England in the western North Sea. The concentrations reported are, in general, lower than those published previously for the same area.The distribution of total metal concentration between the dissolved and particulate phases varies for the three elements. The lead distribution is dominated by its associations with particulate material while cadmium shows the reverse behaviour, existing almost totally in the dissolved phase. Copper is intermediate in behaviour, with the dissolved phase generally being dominant.An inverse relationship between salinity and dissolved copper concentration suggests a freshwater origin for this element. It is suggested that sedimentary and/or anthropogenic sources affect dissolved copper concentrations in coastal waters. The dissolved lead distribution reveals plumes of contaminated coastal water. The lead distribution is, however, dominated by associations with particulate material and sediments which produce a sharp concentration gradient close to the coast. The Humber estuary is identified as a significant source of cadmium to the North Sea.     

Copper, lead and cadmium in coastal waters of the western North Sea

Cadmium, lead and copper have been determined in both dissolved and particulate phases for 130 surface-water samples from the coastal zone of Scotland and England in the western North Sea. The concentrations reported are, in general, lower than those published previously for the same area.The distribution of total metal concentration between the dissolved and particulate phases varies for the three elements. The lead distribution is dominated by its associations with particulate material while cadmium shows the reverse behaviour, existing almost totally in the dissolved phase. Copper is intermediate in behaviour, with the dissolved phase generally being dominant.An inverse relationship between salinity and dissolved copper concentration suggests a freshwater origin for this element. It is suggested that sedimentary and/or anthropogenic sources affect dissolved copper concentrations in coastal waters. The dissolved lead distribution reveals plumes of contaminated coastal water. The lead distribution is, however, dominated by associations with particulate material and sediments which produce a sharp concentration gradient close to the coast. The Humber estuary is identified as a significant source of cadmium to the North Sea.     

Coastal Upwelling Activity on the Pacific Shelf of the Baja California Peninsula

High primary productivity on the Pacific coast of the Baja California Peninsula is usually related to coastal upwelling activity that injects nutrients into the euphotic zone in response to prevailing longshore winds (from the northwest to north). The upwelling process has maximum intensity from April to June, with the coastal upwelling index varying from 50 to 300 m³/s per 100 m of coastline. Along the entire coast of the peninsula, the upwelling intensity changes in accordance with local wind conditions and bottom topography. Spatial variability can also be modulated by the influence of mesoscale meanders of the California Current. We have identified the seasonal and synoptic variability of upwelling signatures on the Baja California shelf, using averaged monthly and weekly sea surface temperature (SST) distributions obtained from remote sensing imagery from the Advanced Very High Resolution Radiometer in the period from 1996 to 2001. Analysis of SST distribution and direct experimental data on temperature and nutrient concentration shows that the areas with the coldest SST anomalies were closely related to the bottom slope, shelf width, and coastline orientation relating to wind direction. We also assume that the nutrient transport into the coastal lagoons may be forced by the coupling of coastal upwelling and tidal pumping of surface waters into the lagoon system. This revised version was published online in August 2006 with corrections to the Cover Date.     

A model study of influence of circulation on the pollutant transport in the Zhujiang River Estuary and adjacent coastal waters

A tracer model with random diffusion coupled to the hydrodynamic model for the Zhujiang River Estuary (Pearl River Estuary, PRE) is to examine the effect of circulations on the transport of completely conservative pollutants. It is focused on answering the following questions: (1) What role does the estuarine plume front in the winter play in affecting the pollutants transport and its distribution in the PRE ? (2) What effect do the coastal currents driven by the monsoon have on the pollutants transport? The tracer experiment results show that: (1) the pollutant transport paths strongly depend on the circulation structures and plume frontal dynamics of the PRE and coastal waters; (2) during the summer when a southwesterly monsoon prevails, the pollutants from the four easterly river inlets and those from the bottom layer of offshore stations will greatly influence the water quality in Hong Kong waters, however, the pollutants released from the four westerly river-inlets will seldom affect the water quality of Hong Kong waters due to their transport away from Hong Kong; (3) during the winter when a northeasterly monsoon prevails, all pollutants released from the eight river gates will be laterally transported seaward inside the estuary and transport westward in the coastal waters along the river plume frontal zone. However, pollutants released from the surface layer of offshore stations near or east of the Dangan Channel will be carried into the coastal waters of Hong Kong by the landward component of the westward coastal current driven by the winter northeasterly monsoon. But the pollutants from the bottom layer of the offshore stations will be carried away from the offshore by the bottom flow driven by the northeasterly monsoon. This implies that only surface-released matter from offshore stations will affect the water quality of the coastal waters around Hong Kong during the winter when a northeasterly monsoon prevails.     

A model study of influence of circulation on the pollutant transport in the Zhujiang River Estuary and adjacent coastal waters

A tracer model with random diffusion coupled to the hydrodynamic model for the Zhujiang River Estuary (Pearl River Estuary, PRE) is to examine the effect of circulations on the transport of completely conservative pollutants. It is focused on answering the following questions: (1) What role does the estuarine plume front in the winter play in affecting the pollutants transport and its distribution in the PRE? (2) What effect do the coastal currents driven by the monsoon have on the pollutants transport? The tracer experiment results show that: (1) the pollutant transport paths strongly depend on the circulation structures and plume frontal dynamics of the PRE and coastal waters; (2) during the summer when a southwesterly monsoon prevails, the pollutants from the four easterly river inlets and those from the bottom layer of offshore stations will greatly influence the water quality in Hong Kong waters, however, the pollutants released from the four westerly river-inlets will seldom affect the water quality of Hong Kong waters due to their transport away from Hong Kong; (3) during the winter when a northeasterly monsoon prevails, all pollutants released from the eight river gates will be laterally transported seaward inside the estuary and transport westward in the coastal waters along the river plume frontal zone. However, pollutants released from the surface layer of offshore stations near or east of the Dangan Channel will be carried into the coastal waters of Hong Kong by the landward component of the westward coastal current driven by the winter northeasterly monsoon. But the pollutants from the bottom layer of the offshore stations will be carried away from the offshore by the bottom flow driven by the northeasterly monsoon. This implies that only surface-released matter from offshore stations will affect the water quality of the coastal waters around Hong Kong during the winter when a northeasterly monsoon prevails.     

Tidal front and its relation to the biological process in coastal water

A tidal front is a unique structure in coastal waters where tidal mixing is dominant during the summer. Various indexes to define tidal fronts and their dynamics have been reviewed in coastal waters where tidal mixing is dominant. The classification of a front in coastal waters is determined by the freshwater inflow, heating/cooling, Ekman transport, and mixing intensity. The strength of mixing plays an important role, dynamically, in creating a tidal front. The hydrography and circulation around a tidal front are crucial in the biological processes leading to the cross-frontal transport of nutrients and phytoplankton blooms. Physical-biological cooperation is necessary to clearly assess the impact of a tidal front on the distribution of phytoplankton and chlorophyll a in the tidal front area.     

Hydrographical characteristics and oxygen isotopic signatures of water in a coastal environment (Mangalore) along the southeastern Arabian Sea

Coastal marine environments are important links between the continents and the open ocean. The coast off Mangalore forms part of the upwelling zone along the southeastern Arabian Sea. The temperature, salinity, density, dissolved oxygen and stable oxygen isotope ratio (δ¹⁸O) of surface waters as well as those of bottom waters off coastal Mangalore were studied every month from October 2010 to May 2011. The coastal waters were stratified in October and November due to precipitation and runoff. The region was characterised by upwelled bottom waters in October, whereas the region exhibited a temperature inversion in November. The surface and bottom waters presented almost uniform properties from December until April. The coastal waters were observed to be most dense in January and May. Comparatively cold and poorly oxygenated bottom waters during the May sampling indicated the onset of upwelling along the region. δ¹⁸O of the coastal waters successfully documented the observed variations in the hydrographical characteristics of the Mangalore coast during the monthly sampling period. We also noted that the monthly variability in the properties of the coastal waters of Mangalore was related to the hydrographical characteristics of the adjacent open ocean inferred from satellite-derived surface winds, sea surface height anomaly data and sea surface temperatures.     

Formation of the coastal current in the Black Sea caused by spatially inhomogeneous wind forcing upon the upper quasi-homogeneous layer

A poorly known mechanism of formation of a warm coastal current by spatially nonstationary and nonuniform wind forcing in the northeastern part of the Black Sea is described. Owing to the blocking influence of the Caucasian Mountains, the northeasterly wind (nordost) west and east of Tuapse is characterized by a spatially nonuniform speed distribution over the Russian sector of the sea. In the first half of the year, during the nordost wind, the intense wind forcing upon the upper quasi-homogeneous layer (UQL) leads to its fast cooling due to the turbulent entrainment of cold waters from the shallow seasonal thermocline. Satellite data and measurements from ships obtained at the end of June-beginning of July 2006 showed that, during two days, the temperature of the UQL west of Tuapse dropped by 7–10°C, whereas, east of Tuapse where the wind was weak, it practically did not change. As a result, a narrow frontal zone between the warm (less dense) and cold (denser) upper layer waters oriented quasi-normally to the shore was formed. A hydrodynamic analysis showed that, in such situation, an intense jet of a near-shore density current is developed that transports warm waters to the northwest at a velocity of 40–60 cm/s. This estimate agrees well with satellite data and observations from ships. The satellite data allowed us to find that this jet reached the Kerch Strait region in a few days. During the time of its existence (approximately 2 weeks), the jet transports a large volume of water and can change the functioning regime of the coastal ecosystem. The mechanism of the near-shore current formation revealed may also function in other seas and oceanic regions.     

Primary production in the eastern tropical Pacific: A review

The eastern tropical Pacific includes 28 million km² of ocean between 23.5°N and S and Central/South America and 140°W, and contains the eastern and equatorial branches of the north and South Pacific subtropical gyres plus two equatorial and two coastal countercurrents. Spatial patterns of primary production are in general determined by supply of macronutrients (nitrate, phosphate) from below the thermocline. Where the thermocline is shallow and intersects the lighted euphotic zone, biological production is enhanced. In the eastern tropical Pacific thermocline depth is controlled by three interrelated processes: a basin-scale east/west thermocline tilt, a basin-scale thermocline shoaling at the gyre margins, and local wind-driven upwelling. These processes regulate supply of nutrient-rich subsurface waters to the euphotic zone, and on their basis we have divided the eastern tropical Pacific into seven main regions. Primary production and its physical and chemical controls are described for each.Enhanced rates of macronutrient supply maintains levels of primary production in the eastern tropical Pacific above those of the oligotrophic subtropical gyres to the north and south. On the other hand lack of the micronutrient iron limits phytoplankton growth (and nitrogen fixation) over large portions of the open-ocean eastern tropical Pacific, depressing rates of primary production and resulting in the so-called high nitrate-low chlorophyll condition. Very high rates of primary production can occur in those coastal areas where both macronutrients and iron are supplied in abundance to surface waters. In these eutrophic coastal areas large phytoplankton cells dominate; conversely, in the open-ocean small cells are dominant. In a ‘shadow zone’ between the subtropical gyres with limited subsurface ventilation, enough production sinks and decays to produce anoxic and denitrified waters which spread beneath very large parts of the eastern tropical Pacific.Seasonal cycles are weak over much of the open-ocean eastern tropical Pacific, although several eutrophic coastal areas do exhibit substantial seasonality. The ENSO fluctuation, however, is an exceedingly important source of interannual variability in this region. El Niño in general results in a depressed thermocline and thus reduced rates of macronutrient supply and primary production. The multi-decadal PDO is likely also an important source of variability, with the ‘El Viejo’ phase of the PDO resulting in warmer and lower nutrient and productivity conditions similar to El Niño.On average the eastern tropical Pacific is moderately productive and, relative to Pacific and global means, its productivity and area are roughly equivalent. For example, it occupies about 18% of the Pacific Ocean by area and accounts for 22–23% of its productivity. Similarly, it occupies about 9% of the global ocean and accounts for 10% of its productivity. While representative, these average values obscure very substantial spatial and temporal variability that characterizes the dynamics of this tropical ocean.     

近50年来长江口及邻近海域溶解氧的时空分布变化

长江口及邻近海域是我国最重要的河口海岸区域之一。基于多源、长时间序列的溶解氧资料,本文对近50年来长江口及邻近海域溶解氧的时空分布特征进行了研究。结果表明,近50年来,长江口及邻近海域表层溶解氧基本保持稳定,仅冬季呈现出一定的上升趋势。冬、春两季溶解氧浓度范围在7-11 mg/L,夏、秋两季为6-8 mg/L。长江口及邻近海域低氧值首先出现于5月,浙闽沿岸底层海域形成低氧水舌。水舌在夏季不断向北推进,北部断面低氧程度明显高于南部断面。到了秋季,低氧区逐渐消退,至冬季完全消失。在过去的50年中,长江口及邻近海域的低氧现象始于20世纪80年代。2000年起,低氧程度逐渐加深,低氧分布深度逐渐升高。本文基于大量的溶解氧历史数据开展研究,研究结论对于探讨长江口及邻近海域低氧区的发展变化具有非常重要的意义。     

千里崖海域真光层光衰减

根据1986年6月在黄海中部的千里崖海域的水光学实测资料和实验室光学测量,讨论了真光层内光衰减系数在遥感和初级生产力中的应用,定量估算影响光衰减的主要物质成分对光衰减的贡献;并探讨了真光层深度、光衰减系数和透明度三者之间的统计关系。     

9914号台风近海强度增强的主因分析

通过对9914号台风近海强度增强原因的分析后认为：台风中心高层流出场增强，辐散加大及弱冷空气触击台风北侧，是9914号台风近海强度增强的主要原因。     

土地利用变化对芝罘连岛沙坝附近海岸带的影响

在RS,GIS技术支持下,经过遥感影像解译获取了研究区1979,1989,1997和2007年4个典型时期土地利用信息,通过对土地利用变化分析,表明近30a来建设用地始终大幅增长,耕地一直大量减少,养殖池和河漫滩从无到有,其他地类呈波动式变化。在快速城市化进程中人类活动对芝罘连岛沙坝附近海岸带产生了深刻影响：其土地利用...     

Distribution et caractérisation par fluorescence de la matiére organique dissoute dans les eaux de la Manche centrale

Intensity and spectral characteristics of the fluorescence of water samples collected along the transect Cherbourg-Isle of Wight during four cruises for excitations at 370, 313 and 270 nm have been investigated within the framework of the FluxManche II program. Seasonal and spatial differences appeared to reflect on the one hand, variations in terrestrial inputs, and on the other hand, waters masses structuring. The observed linear variation of the fluorescence intensity with salinity indicates a gradual dilution of the continental humic material in going from the coasts to the central part of the English Channel. The largest signal was observed for the English coastal waters in agreement with important terrestrial inputs from the Solent river. While the fluorescence intensity was not found to be correlated with the DOC, it shows a good correlation with the nutrients. This result could indicate both a supply from terrestrial inputs and an almost simultaneous autochtonous regeneration. As similarly reported for waters in the eastern part of the French coastal zone, excitation at 313 nm gives evidence for the presence of two classes of fluorescent dissolved organic matter. These two fluorescent components are indicative of the simultaneous presence of continental humic substances and substances whose assignment to marine humic substances or to heterotrophic related substances are still an open question. As compared to the eastern part of the Channel along the French coasts, excitation at 270 nm indicates a lower content of protein-like compounds which may be related to a lower biological activity along the transect or may be due to the fact that the samplings were made out of the phytoplanktonic bloom period (April–May 1995).     

Integrated coastal resources management and community participation in a small island setting

The concept of integrated coastal zone management must be rethought to adapt it to the geography and social conditions of small islands. Because of their size, all small islands are in the coastal zone. Defining the whole of the island and its coastal waters as the management area may weaken a program's effectiveness. An alternative may be to adapt special area management planning to the socio-spatial organization found on small islands. Social conditions on islands, where people live in relatively small cohesive communities, makes resource user participation in planning and management particularly germane. This paper outlines an argument for small islands to use participation as a central strategy of coastal management based on experience with natural resource management efforts on the island of Pohnpei in the Federated States of Micronesia.     

胶州湾水域有机农药HCH的分布和稀释过程

根据1983年5月、9月和10月的胶州湾水域调查资料,分析了有机农药六六六(HCH)在胶州湾水域的分布、来源和季节变化。研究结果表明:在胶州湾水域没有受到HCH的污染。通过河流输入近岸水域和通过地表径流直接输入近岸水域的HCH含量是一样的,非常低。HCH来源是面来源。在夏季,输入的胶州湾水域的HCH含量与春、秋季相比,相对较高。根据HCH在胶州湾水域的分布、来源和季节变化,认为1983年HCH含量变化由胶州湾附近盆地的雨量大小所决定。在胶州湾湾口水域,表层的HCH水平分布状况与底层的HCH水平分布状况一致。HCH的含量在表层的减少完全依赖胶州湾潮流的稀释,不仅在水体表层中HCH含量会形成低值区域,而且在水体底层中HCH含量也会形成低值区域。     

The distribution of oxygen and hydrogen sulfide in Black Sea waters during winter-spring period

Regularities of oxygen and hydrogen sulfide are examined, using the method of spatial isopycnic analysis. The contribution that ventilation of winter-time surface waters over the domes of cyclonic gyres makes to the transfer of O₂ towards the upper boundary of the constant pycnocline and to the oxicline layer is demonstrated. The paper provides spatial scales of this phenomenon and indicates the areas where the upper boundary of the anoxic layer in the Black Sea, relative to the conventional density, is located much higher compared with the rest of the sea. The suboxic zone is shown to be a specific feature of the O₂/H₂S distribution in the Black Sea waters, typical, at least, of the northern part of the basin. Analysis of the suboxic spatial variability in the vertical has been conducted. Translated by Vladimir A. Puchkin.     

Observations of a cycle of intense coastal upwelling and downwelling at the research site of the Shirshov Institute of Oceanology in the Black Sea

The paper presents the results of joint analysis of the response of vertical temperature and current velocity profile distributions in the coastal zone of the Gelendzhik region of the Black Sea to strong wind forcing in the third ten-day period of September 2013. This forcing was caused by the propagation of an atmospheric cyclone, which first initiated coastal upwelling that was later replaced by downwelling. We formulate a criterion for the development of full coastal upwelling and demonstrate its efficiency. We assume that frequent events of incomplete coastal upwelling and downwelling are associated with changes in the water dynamics (variations in the intensity and direction of the alongshore current) generally not related to local wind forcing.     

长江口最大浑浊带及邻近水域营养盐的分布特征

根据2003年11月~2004年8月4个航次的调查数据,探讨了长江口最大浑浊带及邻近水域营养盐的分布特征。结果表明,营养盐浓度一般随盐度的增加而减小,不同营养盐表现出不同的平面分布和季节变化特点。最大浑浊带所处地理位置、水动力状况、高悬浮体含量以及生物活动等决定了营养盐分布不同于整个调查水域。与整个调查水域相比,最大浑浊带营养盐浓度更高;无机N的硝化作用进行得更为充分;高的DIN/PO4-P和SiO3-Si/PO4-P比(远高于Redfield比),相对低的SiO3-Si/DIN比等。透明度是最大混浊带浮游植物生长的主要限制因素。营养盐在河口的转移除了海水稀释作用外,还有部分的生物转移以及受悬浮体-沉积物系统的影响,特别是PO4-P。在最大浑浊带,富营养化现象更为严重。     

Meteorologically-induced mesoscale variability of the North-western Alboran Sea (southern Spain) and related biological patterns

Hydrographic mesoscale structures in the North-western Alboran Sea show a high variability induced by a number of different factors. One of the most important is the differences in atmospheric pressure over the Mediterranean basin when compared to the Gulf of Cádiz. This difference modulates the zonal wind field in the Alboran Sea and the intensity of the Atlantic inflow through the Strait of Gibraltar, also affecting the formation and extension of the Western Alboran Gyre (WAG). When westerly winds are dominant, lower atmospheric pressure in the Mediterranean enhances the inflow of Atlantic waters causing the Atlantic Jet to be located in the vicinity of the Spanish shore, creating a well-defined frontal zone in front of Estepona Cove. In this situation, the coastal upwelling is enhanced, leading to a minimum in sea surface temperature and a maximum of surface nutrient concentrations located in the coastal area. The vertical position of the chlorophyll maximum found in these circumstances appeared to be controlled by the nutrient availability. On the other hand, when easterly winds prevail, higher atmospheric pressure in the Mediterranean leads to a reduced inflow and the oceanographic and biological structures are clearly different. The Atlantic Jet moves southward flowing in a south-eastern direction, changing the structure of the currents, resulting in an enhanced cyclonic circulation extending throughout the North-western Alboran Sea basin. These physical alterations also induce changes in the distribution of biogeochemical variables. Maximum nutrient and chlorophyll concentrations are located further off the coast in the central area of the newly created cyclonic gyre. During these easterlies periods coastal upwelling stops and the distribution of phytoplankton cells seems to be mainly controlled by physical processes such as advection of coastal waters to the open sea.