红海及亚丁湾间之海水交换

分析表观耗氧量、滴定碱度及总二氧化碳量等资料来研判红海及亚丁湾间之海水交换。结果显示，红海深层水的方解石及霰石饱和度均比亚丁湾和阿拉伯海深层水的饱和度高。红海全水柱之方解石和霰石都处於过饱和状态，亚丁湾和阿拉伯海中各深度之方解石亦呈过饱和状态，但霰石的饱和深度则大约在５００ｍ左右。分析深层水之生物体无机碳与有机碳的分解比值，可以发现此地区深层水中，大约在２５％的总二氧化碳增加量是由无机碳酸钙溶解而     

红海的碳化学研究

目的是对红海的碳酸盐及其相关的化学做一初步的研究。滴定减度、总二氧化碳量及表观氧消耗量等的垂直剖面图皆和红海深水的流动型式相符合,而由滴定碱度的垂直剖面图可看出红海的碳酸钙似乎有沉淀现象。计算红海方解石和霰石饱和度的结果显示红海全水柱都是处于过饱和状态,而且红海深水的饱和度比印度洋西北部深水的饱和度高。     

南海东北部之海水碳酸盐现况

为探讨南海的海水碳酸盐现况，本文利用“海研一号”三个航次（第266、287及316航次）的机会，搜集南海东北角的碳酸盐因子，如温度盐度、pH值、总碱度及总二氧化碳等。南海深层水具有西菲律宾海水深约2200m的水团特性，实测结果显示此两水团的碳酸盐因子并没有明显的差异。由滞留时间、无机碳及有机碳分解速率计算结果显示，南海深层水的滞留时间以40a较为合理。     

南海东北部海区碳酸钙的饱和面、溶跃面和补偿深度

南海东北部碳酸钙地球化学研究得出:上层海水中方解石饱和度450—550％,文石饱和度250—350％.300m以深下层海水方解石与文石饱和度和深度的对数直线相关.深层水中二氧化碳含量0.03mmo1·dm~-3,碳酸根含量0.094mmol·dm~(-3),碳酸氢根含量2.35mmol·dm~(-3)总二氧化碳2.48mmo1·dm~(-3);方解石的饱和面1630m,溶跃面3000m,补偿深度4600m,文石饱和面435m,补偿深度1000m.     

珍珠和贝壳的晶体结构新结论

国内外贝类学界都认为贝壳角质层仅由贝壳素构成.棱柱层由方解石构成.珍珠层通常为霰石构成.日本的小林新二郎提出棱柱珍珠是方解石结构,国内外许多论文对此都没有提出异议.本研究采用X-射线对贝壳和棱柱珍珠衍射结果证明:(1)贝壳珍珠层全是是霰石结构,只有牡蛎(Ostrea rivularis)壳例外,符合以上理论;(2)棱柱层几乎全是霰石结构,只有牡蛎壳和紫色裂江珧(Pinna atropurpurea)壳的棱柱层是方解石结构,基本否定了以上理论;(3)角质层由有机物—贝壳素和方解石或霰石组成的,有些还含二氧化硅等杂质,这不完全相符上面理论;(4)棱柱珍珠完全是霰石结构,证明小林新二郎的结论是错误的.     

船到亚丁湾

“雪龙”号过红海进入阿拉伯湾时,主机出了故障。我们只好驶入就近的也门共和国的亚丁港修理,被迫在亚丁港停泊了近一个月时间。酷热的亚丁亚丁位于阿拉伯半岛的南部,在红海和印度洋之间,是欧、亚、非三洲的海上交通要道。这里酷热少雨,我们4月初到达时气温已达到38～39℃我们简直像     

海水中总无机碳的气相色谱测定

海水中总无机碳是指溶解在海水中的分子状态的二氧化碳及碳酸盐和重碳酸盐的总和.其含量通常用海水pH值、总碱度以及水温和盐度的资料进行计算.显然,这样计算的结果包含了上述各项参数测定的所有误差,以及由温盐资料导出的无机硼酸盐和碳酸盐离解常数的不准确性.就一般的海洋学所用而言,这样的资料是可行的.但在一些精细的研究中,如海水中的二氧化碳系统的平衡,海水与大气之间气体交换速率等,就需要更准确的资料.海水中总无机碳的气相色谱测定,为直接和准确测定海水中总无机碳的含量提供了新的测试手段.     

青岛近海冬末春初海水碳酸盐体系的特征

通过在青岛近岸海域采集海水样品,测定了海水pH、总碱度(TA)、溶解无机碳(DIC)以及溶解钙离子,并根据这些参数计算了海水中的碳酸氢根、碳酸根等分量以及海水二氧化碳分压(pCO_2)、碳酸钙饱和度等参数。各站点海水pH范围为8.09~8.18,平均8.13;TA范围为2309~2345(mol/kg,平均2325(mol/kg;DIC范围为2158~2200(mol/kg,平均2180(mol/kg;海水中溶解钙离子的浓度为0.3700~0.3732g/kg,平均0.3716g/kg。求得海水pCO_2范围为371~476(atm,平均415(atm;方解石和文石的饱和度范围分别为2.31~2.84和1.45~1.78,平均值分别为2.57和1.61。通过与温度、盐度进行比较,发现冬末春初青岛近岸海域海水总碱度、溶解无机碳和溶解钙离子具有较为均匀的特征,是冬季混合导致的结果。海水pH有一定的变化性,与营养盐和叶绿素a的关系显示,观测区西部已开始增强的生物生产使海水pH升高,pH是该季节影响海水pCO_2、碳酸钙饱和度等参数的主要因素。该季节青岛近海总体上表现为大气CO_2的弱源,但西部海区是大气CO_2的弱汇。     

夏季黄海海水碳酸盐体系特征

根据2016年7月对黄海海域碳酸盐体系参数pH和总碱度(A_T)开展的调查,结合温度、盐度、营养盐及叶绿素等同步观测数据,分析了夏季黄海海水碳酸盐体系的特征并讨论了其控制机制。结果表明,碳酸盐体系特征在不同水团间差异很大。表层与底层pH分别在7.915~8.307和7.849~8.074之间,高值位于长江冲淡水和黄海沿岸流中。表层与底层A_T分别为2063~2358μmol/kg和2205~2372μmol/kg,总体表现为由南往北递增。长江冲淡水A_T较低,黄海沿岸流A_T较高。海水总溶解无机碳(C_T)在黄海北部山东半岛附近含量较高,底层明显高于表层。表层海水二氧化碳分压(pCO_2)与表层C_T变化趋势相似。霰石饱和度(?_(Ar))在底层较低,最低值仅为1.28。Pearson相关分析结果显示,水团中A_T与盐度的相关性较大(R0.7),pH与营养盐的相关性较大。说明碳酸盐体系特征主要受水团混合和生物活动的影响。水团混合是影响A_T分布的主导因素。表层营养盐浓度过低导致浮游植物生长受限,受限区域pH变化不大,底层再矿化过程释放大量CO_2导致底层pH降低。     

蓝镜头

红海位于非洲东北部与阿拉伯半岛之间,形状狭长。红海北端分叉成两个小海湾,西为苏伊士湾,东为亚喀巴湾。南部通过曼德海峡与亚丁湾、印度洋相连。红海连接地中海和阿拉伯海,是一条重要的石油运输通道。图为静静的亚喀巴湾。海洋保护区中,也只有不到1/3被有效地管理起来,绝大部分仍缺乏有效的管理。     

Water masses in the Gulf of Aden

Hydrographic data collected from Gulf of Aden since 1920 have been compiled to identify and refine the definitions of water masses in the Gulf of Aden (GA) and to describe their spatio-temporal variability. Four water masses have been identified based on their θ-S characteristics. The Red Sea Water (RSW) that flows from the Red Sea is the most prominent water in the GA; this occupies about 37% of the total volume of Gulf of Aden. The Gulf of Aden Surface Water (∼3%) forms as a mixture of local water and the water from western Arabian Sea during winter and Red Sea surface water during summer. The intermediate water, identified as Gulf of Aden Intermediate Water (GAIW), occupies about 9% of the total volume of GA; a characteristic salinity minimum is associated with it at σ_θ=26.50 kg m⁻³. The northward spread of sub-tropical subsurface water from the south appears to be the major source of GAIW. The bottom water, named Gulf of Aden Bottom Water, showed the least variability. It was formed due to the mixing of Red Sea Water and water of southern origin. Mixing triangles have been used to analyze the composition of water in the GA.     

Zooneuston and zooplankton abundance and diversity in relation to spatial and nycthemeral variations in the Gulf of Aqaba and northern Red Sea

Zooplankton and zooneuston observations were made at seven stations(four from the Gulf of Aqaba and three from the northern Red Sea), during September and October 2016. The main objective of this study was to assess the variability of nycthemeral fauna in relation to the sampling methods using two different types of nets namely,WP2 net and Neuston net along the two study sites, i.e., the Gulf of Aqaba and the northern Red Sea. Zooplankton was sampled vertically using a standard WP2 net from a depth of 200 m to the surface, whereas zooneuston was made using a standard Neuston net from a depth of 0–10 cm of the water surface. Total zooplankton density was maximum during night time((617.83 ± 201.84) ind./m~3) at the Gulf of Aqaba and total zooneuston was maximum during night at the northern Red Sea((60.94±29.48) ind./m~3), respectively. The most abundant taxa were Copepoda, Gastropoda, Bivalva, Chaetognatha, Tunicata and Ostracoda. The abundance was almost 50% higher at night time at both the Gulf of Aqaba and the northern Red Sea. Overall, 30 taxa covering 10 phyla and 27 taxa covering 8 phyla were recorded in the Gulf of Aqaba and the northern Red Sea.     

Calculation of energy of the barotropic-baroclinic interaction in the strait of Bab el Mandeb

Equations for the kinetic, potential, and total energy in the curvilinear boundary-fitted coordinates are considered in the strait area and adjacent regions of the Red Sea and Gulf of Aden. The budgets of different forms of energy are presented, making it possible to assess the correctness of the formulation of the three-dimensional boundary-value problem, the accuracy of the calculation of the barotropic-baroclinic interaction in an energy norm, and the relationship between the components of energy balance. The energy fluxes in the boundary sections of the strait are estimated for the interaction of thermohaline currents with main tidal harmonics and with the total tide, as well as for the amplitude of fluctuations in boundary energy fluxes in a synodic month. The results illustrating the behavior of some dynamical characteristics and components of energy balance at vertical and horizontal sections of the strait are given.     

Sustainable use of renewable resources and conservation in the Red Sea and Gulf of Aden: issues,needs and strategic actions

The coastal and marine environments and resources of the Red Sea and Gulf of Aden are globally significant and generally in a healthy state. Current regional issues include localized destruction of coral reefs, seagrass and mangroves; declines in some fisheries; exploitation of some endangered species; pollution from the development and transport of petroleum; and disposal of industrial and municipal wastes. The underlying causes of these issues are the natural vulnerability of the Red Sea due to its semi-enclosed nature; economic reliance on the petroleum industry; significant navigation risks; a rapidly increasing coastal population and associated developments; lack of fisheries information, surveillance and management; poor coastal zone planning; and limited technical expertise. Strategic actions addressing these issues will need to be implemented regionally and focus on coastal zone management that integrates environmental planning, environmental assessment and review; training and institutional development; public awareness and participation; information gathering especially fisheries statistics; reducing navigation risks; and the development of resource management and conservation strategies.     

How does the Red Sea outflow water interact with Gulf of Aden Eddies?

As the Red Sea overflow water (RSOW) enters the Gulf of Aden (GOA), it interacts with a sequence of nearly barotropic, mesoscale eddies originating in the Indian Ocean. To investigate how these eddies impact the dispersal and eastward transport of the RSOW toward the Indian Ocean, a high resolution 3D regional model is employed to explore systematically the interaction between the RSOW and mesoscale eddies. Two types of experiments are conducted. In the first set, we simulate the behavior of RSOW in the presence of an idealized cyclone and an idealized anticyclone. The second type of simulation involves nesting of the regional model (ROMS) within a data-assimilating global model (HYCOM), in which a sequence of mesoscale eddies entering the Gulf of Aden is realistically captured. This simulation is integrated for one year, and includes a simple representation of the seasonality of the RSOW.Bower et al. (2002) suggest that the Red Sea overflow might be a western boundary undercurrent. Consistent with these expectations, the idealized simulations show that the preferred pathway of the RSOW in the absence of eddies is along the coast of Somalia (southern continental shelf) as a western boundary undercurrent. Simultaneously, a cyclonic circulation is generated in the far western GOA due to vortex stretching by the descending outflow. The presence of a cyclone in the western GOA increases the peak RSOW transport, but the cyclone itself rapidly loses its coherence after interacting with the rough topography in the western GOA. The presence of an anticyclone tends to block the preferred boundary pathway and inhibits the eastward transport of the RSOW. The eddies also result in substantially increased mixing of the RSOW in the western GOA.On the basis of the more realistic ROMS experiment, it is found that the modeled RSOW leaves the western part of the Gulf of Aden in short episodic bursts with transports that are an order of magnitude greater than that associated with the quasi-steady RSOW inflow into GOA. Such enhancement in RSOW transport is shown to be induced by cyclonic eddies that cause a rapid discharge of RSOW from the western part of the GOA. We conclude that mesoscale eddies play a key role in the transport and mixing of the RSOW within GOA.     

Development of small-scale fisheries in Yemen: An exploration

Yemen is one of the poorest countries in the world. The development of its fishery sector is increasingly being mentioned as a source of livelihood creation. The aims of this paper are to: (a) provide an overview of the institutional environment in which small-scale fishermen in Yemen operate; (b) investigate the constraints they face; and (c) discuss the potential role that co-operatives could play in such development. Small-scale fisheries in Yemen are increasingly important, yet they struggle with access to infrastructure, markets, and credit. We identify significant differences in the development of the fisheries sector in the two main fishing regions: the Gulf of Aden and the Red Sea. Overall, local capacity within co-operatives needs to be improved and private sector development should be encouraged.     

东海钙质生物骨屑的矿物学特征

通过电镜、电子探针和X射线等项分析,对东海沉积物中的有孔虫、腹足类、双壳类、苔藓、珊瑚、海胆等骨屑进行了矿物学研究,确定了矿物成分与生物属种的关系,并基于有孔虫壳体化学成分将壳体分为均质壳和异质壳,生物碳酸盐中镁主要富集在方解石及镁方解石中,锶在方解石和镁方解石中的分配系数(D)相似,为0.11—0.14;在文石质骨屑中D=1.09-1.20。碳氧同位素组成与生物属种有明显关系。据一些有孔虫壳体氧同位素偏差值计算的水温来看,本次测定的有孔虫属种的骨屑不能作为理想的骨屑温度计。     

日本海西部大陆坡自生碳酸盐的特征与成因

对日本海西部大陆坡沉积物柱状样中的自生碳酸盐样品进行了X射线衍射、扫描电镜、地球化学和碳氧同位素组成的系统研究。X射线衍射和扫描电镜分析结果表明,碳酸盐主要组成矿物为颗粒状自生高镁方解石微晶,放射状自生文石微晶仅在一个层位出现。结合碳酸盐的地球化学组成,认为研究区碳酸盐来自于富Ca2+、Mg2+和HCO3-流体的沉淀。中度亏损的13C(-33.85‰～-39.53‰)表明碳来自于甲烷的厌氧氧化,同时,这也是研究区海底存在甲烷冷泉的重要证据。重氧同位素比值(5.28‰～5.31‰)则指示着富18O流体来源,而该流体应源于天然气水合物的分解。综上可知,研究区碳酸盐来自于研究区甲烷冷泉上升流的沉淀,指示着海底更深处天然气水合物的存在与分解。