The recovery of the Barents Sea capelin (Mallotus villosus) from a larval point of view     

Fossum  P. 《ICES Journal of Marine Science》1992,49(2):237-243

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The intertidal erosion rate of cohesive sediment: a case study from Long Island Sound   总被引：2，自引：0，他引：2  

Y. H. Wang   《Estuarine, Coastal and Shelf Science》2003,56(5-6):891-896

Over the past decades, many attempts have been made to generate useful bottom erosion models for the study of cohesive sediment movement. This study addresses some of the key questions involved in determining the functional relationship between erosion rate and bottom shear stress. Current, wave, and turbidity data were collected from a bottom mounted instrument array in a moderately energetic estuarine environment. The bottom shear stress was calculated from a wave–current interaction model. The erosion rate was derived from the observed sediment concentration using a vertical mixing model. Examination of the relationship between erosion rate and bottom stress showed that the erosion rate varied at intertidal frequency. When averaged over the tidal fluctuation, the erosion rate remained approximately constant at low stress, but increased sharply when the shear stress rose above a critical value. This suggests two-stage erosion. The bed has a layered structure, in which a thin layer of loose, high water content material overlies a more consolidated bed. The top layer of high water content material (fluff) was easily disturbed and re-suspended by tidal currents, but the consolidated bottom layer was eroded only under conditions of high shear stress.  相似文献   

两种海洋微藻硝酸还原酶活性测定方法的比较研究   总被引：1，自引：0，他引：1  

唐洪杰  王修林  祝陈坚  李雁宾  张传松 《中国海洋大学学报(自然科学版)》2006,36(6):981-986

对6种常见海洋微藻的硝酸还原酶活性测定方法进行了初步研究。确立了离体法和活体法的提取(振荡)时间及酶促反应时间,分别为:5 min,30 min(离体法)和6 min,10 min(活体法),并对2种方法进行了对比。结果表明:在本文条件下,离体法较活体法更适于进行塔玛亚历山大藻(Alexandrium tamarense)、强壮前沟藻(Amphidinium carterae)、中肋骨条藻(Skeletonema costatum)、新月菱形藻(Nitzchia closterium)和旋链角毛藻(Chaetoceros curvisetus)的硝酸还原酶活性的测定;活体法更适于东海原甲藻(Prorocentrum donghainase)硝酸还原酶活性的测定。  相似文献   

Consequences of growth variation in northern Baltic herring for assessment and management     

Rahikainen  Mika; Stephenson  Robert L. 《ICES Journal of Marine Science》2004,61(3):338-350

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河口海岸环境沉积速率研究方法   总被引：22，自引：0，他引：22  

王永红  沈焕庭 《海洋地质与第四纪地质》2002,22(2):115-120

沉积速率是河口海岸沉积环境的重要参数，对于河口海岸地质历史时期沉积速率的研究，大多采用^14C年龄值计算；现代河口海岸沉积速率的研究方法较多，常见的有河流输沙法，海图对比法，GIS法，放射性同位素测年法等。^14C法结合考古，孢粉等方法，能比较真实地反映河口海岸地质历史时期的沉积速率，对于现代河口海岸沉积，由于GIS和DEM方法的发展和计算机功能的支持，使海图对比的方法克服了手工带来的误差，目前仍然是一种可以使用的方法。放射性同位素^210Pb,^137Cs,^239,240Pu法使沉积速率的计算趋于定量化，在一定时间区域范围内，多种同位素测年同时运用，相互印证，从而使河口现代沉积速率更加准确。  相似文献   

浙江省海塘塘顶高程的确定   总被引：10，自引：1，他引：10  

黄世昌  周骥等 《海洋工程》2001,19(4):67-71

介绍了浙江省海塘塘顶高程确定时所涉及的波浪爬高，越浪量等的计量，同时分析了1997年后浙江省海塘塘顶高程确定的方法，由已建海塘的塘顶高程分析可见，在背水坡和塘顶有保护措施的情况下，采用允许最大越波流量来控制海塘塘顶高程，可适当降低塘身高度。  相似文献   

莫桑比克罗非鱼孵卵期间口腔粘膜变化的研究     

楼宝城  林华英  蒋明星 《中国海洋大学学报(自然科学版)》1990,(2)

用组织学、组织化学和酶技术,对雌性莫桑比克罗非鱼在孵卵前后口腔粘膜的组织结构、抗菌酶的比活力变化进行初步研究。结果表明:在口腔粘膜的上皮中,杯状细胞是一个重要的结构,它随着雌鱼的生理状态的改变而变化。雄鱼、雌鱼和孵卵期的雌鱼口腔粘膜上皮中的杯状细胞数量上的差别显著。孵卵期的雌鱼口腔粘膜类似于哺乳动物的子宫粘膜也是受性激素影响的靶器官。该种鱼的口腔粘膜中存在着两种抗菌酶;蛋白质水解酶和壳多糖酶。孵卵前后,这两种酶的比活力分别提高1.4—2.03倍。说明孵卵时,口腔粘膜为使卵及仔鱼健康的发育,增强了抗菌能力。研究结果证明:抗菌力的增加与口腔粘膜中的杯状细胞的大量增生有着密切的关系。  相似文献   

Alkaline Phosphatase Activity in the Red-Tide Dinoflagellate, Ptychodiscus brevis     

G.A. Vargo  E. Shanley 《Marine Ecology》1985,6(3):251-264

Abstract. Alkaline phosphatase activity (APA) was found in a nearshore, natural population of the red-tide dinoflagellate Ptychodiscus brevis. Initial hydrolysis rates were enhanced by two orders of magnitude within 24 h upon addition of ammonium. Other nutrient (additions) or no additions also lead to a higher, although less pronounced increase in activity. Enhanced growth after nutrient additions combined with specific APA indicated that the bloom was both N and P limited. Since the natural population was a mixture of diatoms and the dinoflagellate, APA was also measured in unialgal cultures of P. brevis. APA was not reduced but enhanced by the addition of low concentrations of orthophosphate (0.5 and 1 μM). Higher orthophosphate concentrations (5 to 20 μM) reduced APA, although activity returned to control levels within 2 to 6h. Repression occurred within 30 sec after a 20 μM orthophosphate addition. Cells which had APA repressed by an orthophosphate addition regained their initial activity within 2 h after washing with phosphate-free media. Phosphorus-deficient cells of P. brevis possess an alkaline phosphatase system which is capable of continued activity at low in situ orthophosphate levels.  相似文献   

湄洲湾夏季油的分布特征与防护对策     

王宪  陈于望 《台湾海峡》1996,15(3):265-269

本文根据１９９２年夏季对湄洲湾水质环境质量调查资料，对该海区海水中油的含量及分布特征进行了分析研究。结果表明：湄洲湾夏季表层海水油的含量为５－５１μｇ／ｄｍ＾３，平均值为１９．８μｇ／ｄｍ＾３。海水的混合系数较小，高潮和低潮时油含量分布的差异，除了与陆源污染源分布有关外，主要是由水文动力学条件所决定。  相似文献   

Shallow-Water Gasohydrothermal Vents of Ushishir Volcano and the Ecosystem of Kraternaya Bight (The Kurile Islands)   总被引：2，自引：0，他引：2  

V. G. Tarasov    M. V. Propp    L. N. Propp    A. V. Zhirmunsky    B. B. Namsakakv    V. M. Gorlenko  D. A. Starynin 《Marine Ecology》1990,11(1):1-23

Abstract. A marine ecosystem in the crater of the Ushishir Volcano (Kraternaya Bight, Yankich Island, the Kuriles) showing gasothcrmal activity was studied for hydrographical, hydrochemical, and biological characteristics. Maximal changes in chemical and biological characteristics were observed in the surface water layer of 0–5 m. This layer had higher water temperature, was saturated with volcanogcnic carbon dioxide (up to 2000 10^-6 torr), ovcrsaturatcd with oxygen (up to 200 %), and contained high concentrations of chlorophyll a. Hydrogen sulfide was found in the surface water layer and at a depth of 15 m in the area of maximal effect of volcanic effluents.
The planktonic community is characterized by high rates of production and destruction of organic matter only in the 0–5 m layer. Daily vertical migrations of the ciliatc Mesodinium rubrum were observed, which caused "red tides".
Bacterial, algobacterial, and diatom mats developed on the bottom of the bight in the zone of gasohydrothermal vents and in areas of volcanic water seeping. The rate of organic matter production in algobacterial mats reached 33.4g C-rrr²-d^-l, chcmolithotrophy predominating. Bottom settlements had high population density and great animal biomass, which reached 10 kg m^-2 in gasohydrothermal fields. They obtain sufficient energy from primary production of microphy-tobenthos, algobacterial, and bacterial mats. Bcnthic species dominant in the bight were not found off the Ushishir Islands.
Some species of macrobenthos inhabiting the Kraternaya Bight differ markedly in size and biomass from the same species found beyond the bight.  相似文献