Seasonal and Spatial Variations of Total Mass Flux around Coral Reefs in the Southern Ryukyus,Japan     

Mohamed?IsmailEmail author  Tadashi?Kimura  Yumiko?Suzuki  Makoto?Tsuchiya 《Journal of Oceanography》2005,61(3):631-644

Total mass flux, size distribution of sediment particles and some chemical components such as total carbon (TC), total nitrogen (TN) and calcium carbonate (CaCO₃) were monitored monthly using a multi-cup sediment traps at seven coral reef sites (6 reef flat and 1 reef slope) of the Marine Protected Areas around Ishigaki, Kohama, Kuroshima and Iriomote Islands in the southern Ryukyus, Japan from September 2000 to September 2001. The size distribution of trapped sediments revealed mostly uni-modal fine sand to mud in the reef flat and gravelly to coarse sand in the reef slope. The total mass flux ranged between 0.54 to 872 gm⁻²d⁻¹, and showed a pronounced seasonality (high in summer-autumn and low in spring) at each site, which was consistent with the rainfall and typhoon regime. Exceptionally high values were observed on the reef slope (Iriomote) in February–March 2001 (1533 gm⁻²d⁻¹) owing to a large amount of bottom sediment re-suspension. On the reef flat (Todoroki South and North; Ishigaki), values obtained in July–August 2001 (872 gm⁻²d⁻¹) and August–September 2001 (800 gm^{− 2}d⁻¹) indicate the high terrestrial discharge from Todoroki River. Trapped sediment particles consist of CaCO₃ (1.2–27.1%) and a non-carbonate fraction (98.8–72.9%), which contains total carbon (4.9–26%), carbonate carbon (CO₂-C) (0.2–3.1%) and non-carbonate carbon (NC-C) (7.9–25.6%). Total nitrogen content was in the range 0.02–0.48%. TN is contained mainly in the carbonate fraction and NC-C may be contained in the non-carbonate fraction. The low TN/OC ratio of the trapped sediments suggests that they were mostly of terrestrial origin and that both fractions migrated. The high total mass flux derived from Todoroki River exceeded the threshold at which a lethal effect on coral community is caused. The results stress the importance of conducting seasonal studies of sedimentation over more than one year and at more than one location in south Japan coral reef ecosystems to gain an understanding of the processes controlling the total mass fluxes and their nutrients content, also to develop an awareness of how to prevent the damage of coral reef ecosystems and, if it does occur, to allow mitigation measures to be undertaken.  相似文献   

Influence of Current Width Variation on the Annual Mean Transport of the East Sakhalin Current: A Simple Model     

Yoichi?ShimadaEmail author  Atsushi?Kubokawa  Kay?I.?Ohshima 《Journal of Oceanography》2005,61(5):913-920

Recent observations suggest that the annual mean southward transport of the East Sakhalin Current (ESC) is significantly larger than the annual mean Sverdrup transport. Motivated by this observational result, transport of a western boundary current has been investigated using a simple numerical model with a western slope. This transport is defined as the instantaneous barotropic transport integrated from the western boundary to the offshore point where the barotropic velocity vanishes. The model, forced by seasonally varying wind stress, exhibits an annual mean of the western boundary current transport that is larger than that of the Sverdrup transport, as observed. The southward transport from October to March in the model nearly equals the instantaneous Sverdrup transport, while the southward transport from April to September decreases slowly. Although the Sverdrup transport in July vanishes, the southward transport in summer nearly maintains the annual mean Sverdrup transport, because the barotropic Rossby wave cannot intrude on the western slope. This summer transport causes the larger annual mean. Although there are some uncertainties in the estimation of the Sverdrup transport in the Sea of Okhotsk, the seasonal variation of the southward transport in the model is qualitatively similar to the observations.  相似文献   

辽东湾海底残留地貌和残留沉积     

李凡  林美华 《海洋科学集刊》1984,(23):57-68

全新世以来,世界海面大幅度上升,渤海海区发生了明显的海侵,玉木冰期低海面时期的近海广大陆域皆沉溺于海平面以下。辽东湾由于地质构造复杂及沉积作用速度分布不均匀等因素,海底保存了一部分玉木冰期低海面时期陆地或滨海区的地貌形态及相应的老沉积物的遗迹。它们虽然经过了后期水动力条件及沉积作用的改造,但是,仍不同程度地反映出原始地貌的迹象和某种残留沉积的特征。 关于辽东湾残留地貌和残留沉积的问题,过去曾有报道;本文在以往调査的基础上,结合近期有关资料,对此作进一步的探讨。  相似文献   

台湾浅滩西部水域海洋动物的石油烃含量和荧光光谱特征     

贾晓平  林钦  吕晓瑜  宗志伦 《台湾海峡》1990,(3)

本文报道了台湾浅滩西部水域鱼类、虾类和软体头足类动物的总石油烃含量,分析了主3类动物样品的荧光光谱特征,并将本文数据与南海其他水域海洋动物的石油烃含量作了比较。  相似文献   

LZY1—1型光电浊度仪     

郑丽英  林永斌 《台湾海峡》1990,9(1):84-87

本文介绍了LZY_(1-1)型光电浊度仪的设计原理,标定方法及使用结果,该仪器用经典法校准后,能快速测量大批量样品的悬浮物含量。  相似文献   

浙江近海裸鳃类的研究     

林光宇  尤仲杰 《海洋科学集刊》1990,(31):147-162

关于浙江近海的裸鳃类,过去仅有张玺、齐钟彦(1961)、林光宇(1965,1975,1981,1985)洪君超、尤仲杰(1965,1983)等先后零星报道12种,但尚未进行较系统的分类研究。我们整理了中国科学院海洋硏究所历年来在浙江近海进行调查所采集的标本和浙江水产学院1961-1985年在浙江沿海潮间带采集的标本,共鉴定出90种后鰓类。本文报道其中的裸鳃类共32种,分别隶属于14科,17属,其中有1新种,6种在我国为首次记录。 在这些种中,1种是环赤道分布种:海神鳃 Gulaucus (Gulaucus) marinus ；2种分布于大西洋、地中海；太平洋:雪白心海牛 Noumea nivalis,围鳃海牛 Joriana tomentosa;有9种是印度-西太平洋的热带种:双色裸海牛 Gymnodoris bicolor,多枝鬈发海牛Caloplocamus ramosus,草莓叉棘海牛 Rostanga arbutus，网纹舌尾海牛 Glossodoris tinctoria,黑枝鳃海牛 Dendrodoris nigra，溅斑舌尾海牛 Glossodoris aspersa,芽枝鳃海牛Dendrodoris denisoni,红枝鳃海牛 Dendrodoris rubra,白斑马蹄鳃 Sakuraeolis enosimensis；其余是西、南太平洋的热带、亚热带种和少数温带种。浙江沿海和日本南部沿海的共有种有20种之多,可见两地区系之相似。这些种能向北越过长江分布至黄海、渤海的有9种,向南分布到南海的有13种,其区系性质应为热带、亚热带。  相似文献   

三倍体合浦珠母贝不育性研究     

何毛贤  林岳光  姜卫国 《热带海洋学报》1996,(2)

对三倍体合浦珠母贝Ｐｉｎｃｔａｄａｍａｒｔｅｎｓｉｉ（Ｄ．）春、秋两繁殖盛期的生殖腺进行了组织学观察，并对其配子形成及受精、发育进行了研究。结果表明：合浦珠母贝三倍体的生殖腺发育差，生殖细胞数量少，极少个体能见到成熟卵母细胞和精子；三倍体的配子能完成受精作用，能发育至直线铰合期。配子多为非整倍体，其染色体数目多为１４—２８，胚胎染色体数目主要为２８—４２，故胚胎不能正常发育。因此，三倍体合浦珠母贝是不育的．  相似文献   

Relationship between biogeochemical features of biogenic elements and flocculation in the Changjiang Estuary   总被引：1，自引：3，他引：1  

Lin Yi''an  Tang Renyou  Li Yan  Dong Henglin  Guan Xuwei  Chen Yinzu 《海洋学报(英文版)》1995,14(2):225-234

ＲｅｌａｔｉｏｎｓｈｉｐｂｅｔｗｅｅｎｂｉｏｇｅｏｃｈｅｍｉｃａｌｆｅａｔｕｒｅｓｏｆｂｉｏｇｅｎｉｃｅｌｅｍｅｎｔｓａｎｄｆｌｏｃｃｕｌａｔｉｏｎｉｎｔｈｅＣｈａｎｇｊｉａｎｇＥｓｔｕａｒｙ￥ＬｉｎＹｉ＇ａｎ；ＴａｎｇＲｅｎｙｏｕ；ＬｉＹａｎ；Ｄｏ...  相似文献   

赤点石斑鱼人工配合饵料中蛋白质最适含量的研究   总被引：11，自引：1，他引：11  

陈学豪  林利民  洪惠馨 《台湾海峡》1995,(4)

本文探讨了不同蛋白质含量的配合饵料对赤点石斑鱼（Epinephelusakaara）生长的影响。通过60d度验得出：在各配合饵料组中，蛋白质含量为49．52％的试验的相对增重率（46．84％）体长相对增长率（15．96％）、蛋白质效率（60．35％）和饵料转化率（29．85％）等均为最佳。配合饵料组鱼体肌肉营养成分（蛋白质、脂肪、氨基酸和鲜味氨基酸）也均优于对照组，而更接近野生鱼。经回归方程分析，赤点石斑鱼人工配合饵料中蛋白质最适含量为48．37％～49．24％。  相似文献   

海湾扇贝肝素样多糖分离方法的研究     

王长云  管华诗  林洪 《海洋与湖沼》1995,26(S1):66-69

于1992年1月-1993年2月，对从海湾扇贝中提取获得的糖胺聚糖（GAG）用乙醇和溴化十六烷基三甲铵（CTAB）分级分离，并对所得制品用琼脂糖凝胶电泳和高效液相色谱验证，以研究一种简便、快速的分离提纯方法。结果表明，扇贝GAG水溶液在乙醇量60％时分离获得的级分，其GAG－GTAB给合物再用2.0 mol/LNaCl溶液解离得到的主要级分，琼脂糖凝胶电泳和高效液相色谱均显示出单一区带，红外光谱类似干肝素的。证明这一提纯过程是一简便、快速的分离提纯方法。  相似文献