浙江省海岛沿岸水域微生物生态分布   总被引：2，自引：0，他引：2  

史君贤  陈忠元 《海洋学研究》1996,14(2):35-43

文章报道了浙江海岛沿岸水域中异养细菌、氨化细菌和反硝化细菌的数量分布及异养细菌的种群组成。结果表明：本调查海区异养细菌的数量较多，其数量分布范围在２．０４×１０４～８．３６×１０６个／ｄｍ３之间；氨化细菌数量分布范围在３．０×１０３～１．１×１０６个／ｄｍ３之间；反硝化细菌的数量分布范围在３．０×１０２～１．１－１０６个／ｄｍ３之间。细菌的数量与环境中营养盐的浓度之间存在密切关系。在不同的海区异养细菌的种群组成存在一定的差异，在浙北海区，革兰氏阴性菌所占比例为４１．６％，在浙中海区为４６．９％，在浙南海区为６４．９％。  相似文献   

秦山核电站邻近水域环境化学要素特征     

王正方  龚敏 《海洋学研究》1991,9(2):16-21

本文根据1989年4、7、10月和1990年1月(春、夏、秋、冬)秦山核电站邻近水域零点生态调查和水质监测结果的资料整理而成。经研究证明,该海域是河-海混合水域,盐度从小于3至12之间变化,受杭州湾的涌潮、风浪的影响,水体混合比较强烈,悬浮颗粒物质的含量比长江口高。由于该测区所处的海岸、海底地形,生态系统、径流输入以及水体交换状况不同,故其海洋学特征也不相同。  相似文献   

湛江港外海水富营养化水平与浮游植物多样性   总被引：3，自引：0，他引：3  

彭昆仑  贾后磊 《海洋通报》2007,26(2):113-116

利用2001年12月在湛江港外海现场调查的资料,分析研究了湛江港外海水营养化水平及其与浮游植物多样性的关系。结果表明:湛江港外海水营养状态指数由北向南、由湾口向湾外递减;浮游植物多样性指数和均匀度则是由北向南增加,东南部水质较好,东北部水质较差;将营养盐含量及营养状态水平与浮游植物多样性指数和均匀度利用最小二乘法进行相关性,相关性不显著,另外,调查期间氮磷比例均失去平衡,这可能是影响该海域浮游植物量与营养盐水平之间关系的原因。  相似文献   

夏季珠江口外近海沉积物/水界面营养盐的交换通量   总被引：8，自引：1，他引：8  

张德荣  陈繁荣  杨永强  张凌  吕莹 《热带海洋学报》2005,24(6):53-60

基于2002年夏季(7月)对珠江口外近海的生态环境调查,获取了该海域沉积物间隙水的营养盐剖面资料,估算了沉积物/水界面的营养盐交换通量,并且与实验测定的沉积物/水界面交换通量进行了对比。结果表明,沉积有机质在厌氧环境下降解大大提高了间隙水中的铵盐、磷酸盐和硅酸盐含量,导致这些营养盐总体上从沉积物内部向沉积物/水界面转移。但在该界面附近,铵盐被不同程度地硝化,所形成的硝酸盐又被不同程度地反硝化;磷酸盐和硅酸盐交换通量则受到自生矿物沉淀与溶解、吸附与解吸作用的影响,因此营养盐的净交换通量是各种物理、化学和生物作用的综合结果。模拟实验研究显示,该海区NH4+、NO3-、NO2-、PO43-和SiO44-的沉积物/水界面交换通量分别为-0.197—1.93、-0.558—0.178、-0.064—-0.009、-0.079—0.126和-6.89—7.00 mmol.(m2.d)-1。根据营养盐剖面资料计算的交换通量不仅很小,交换通量方向也往往与实验结果不符。  相似文献   

Seasonal variations of alkenones and U₃₇ in the Chesapeake Bay water column     

Jennifer L. Mercer  Meixun Zhao  Steven M. Colman   《Estuarine, Coastal and Shelf Science》2005,63(4):675-682

Alkenone unsaturation indices (U^K₃₇ and U^K′₃₇) have long been used as proxies for surface water temperature in the open ocean. Recent studies have suggested that in other marine environments, variables other than temperature may affect both the production of alkenones and the values of the indices. Here, we present the results of a reconnaissance field study in which alkenones were extracted from particulate matter filtered from the water column in Chesapeake Bay during 2000 and 2001. A multivariate analysis shows a strong positive correlation between U^K₃₇ (and U^K′₃₇) values and temperature, and a significant negative correlation between U^K₃₇ (and U^K′₃₇) values and nitrate concentrations. However, temperature and nitrate concentrations also co-vary significantly. The temperature vs. U^K₃₇ relationships (U^K₃₇=0.018 (T)−0.162, R²=0.84, U^K′₃₇=0.013 (T)−0.04, R²=0.80) have lower slopes than the open-ocean equations of Prahl et al. [1988. Further evaluation of long-chain alkenones as indicators of paleoceanographic conditions. Geochimica et Cosmochimica Acta 52, 2303–2310] and Müller et al. [1998. Calibration of the alkenone paleotemperature index U^K′₃₇ based on core-tops from the eastern South Atlantic and the global ocean (60°N–60°S). Geochimica et Cosmochimica Acta 62, 1757–1772], but are similar to the relationships found in controlled studies with elevated nutrient levels and higher nitrate:phosphate (N:P) ratios. This implies that high nutrient levels in Chesapeake Bay have either lowered the U^K₃₇ vs. temperature slope, or nutrient levels are the main controller of the U^K₃₇ index. In addition, particularly high abundances (>5% of total C₃₇ alkenones) of the tetra-unsaturated ketone, C_37:4, were found when water temperatures reached 25 °C or higher, thus posing further questions about the controls on alkenone production as well as the biochemical roles of alkenones.  相似文献   

Long-Term Investigation of Spatio-Temporal Variations in Faunal Composition and Species Richness of Megabenthos in Ise Bay,Central Japan     

Monthon?Ganmanee  Teruyoshi?Narita  Hideo?SekiguchiEmail author 《Journal of Oceanography》2004,60(6):1071-1083

Based on our long-term data from megabenthos sampling from 1993 to 2002 in Ise Bay, central Japan, we examined spatio-temporal variations in taxon composition, species richness and its distribution of megabenthos in the bay in relation to the occurrence of the oxygen-poor water (i.e. oxygen content less than 3 ppm) in bottom waters of the bay. A total of 261 species were identified including 6 cnidarians, 1 tentaculate, 5 annelids, 71 molluscs, 72 crustaceans, 16 echinoderms, 12 urochordates and 78 pisces. Of the most abundant 10 megabenthos species, the following 4 species of echinoderms made up more than the half of megabenthos biomass: Luidia quinaria, Echinocardium cordatum, Asterias amurensis and Astropecten scoparius. Species richness of megabenthos varied significantly between seasons and among stations. The severity and period of occurrence of the oxygen-poor water developing every summer play an important role in determining spatial distributions of species richness in the bay.  相似文献   

关于南海暖水季节和年际变化的研究   总被引：1，自引：3，他引：1  

王启 《中国海洋大学学报(自然科学版)》2003,33(6):821-824

阐述了研究南海暖水的意义 ,综述了关于南海暖水的现状 ,提出了关于南海暖水季节和年际变化方面应该研究的问题  相似文献   

Response of the barrier island coastal region of southwestern Nigeria to climate and non-climate forcing     

IB Danladi  M Gül  E Ateş 《African Journal of Marine Science》2020,42(1):43-51

Despite threats emanating from the influence of climate and non-climate forcing on the barrier island coastal region of southwestern Nigeria, the extent of the coastal erosion is poorly understood. We report evidence of coastal erosion and sediment accumulation in the region over a 34-year period (1973–2017), using Landsat imagery at intervals of approximately six years. Landsat image corrections and various water-extraction algorithms were used to systematically delineate coastal erosion and accumulation in the area. The region was subdivided into western and eastern subregions separated by Lagos Harbour. In the west, erosion took place during the periods 1973–1979, 1979–1984, 1990–1999 and 2005–2011, whereas in the east, erosion occurred during 1973–1979, 1990–1999 and 1999–2005. Coastal sediment accumulation occurred in the east during 1979–1984, 1984–1990, 2005–2011 and 2011–2017, whereas gains in the west occurred during 1984–1990, 1999–2005 and 2011–2017. The study revealed substantial net erosion of 1 228.1 ha in the region as a whole, over the full period. Sediment accumulation accompanying the coastal erosion appears to be linked to longshore drift. Erosion between 1973 and 2011 was probably attributable to climate change (storms and tidal conditions), longshore drift, the inflow and outflow of water at Lagos Harbour, coastal morphology and, possibly, human impacts. However, the coastal changes between 2011 and 2017 were more obviously associated with human activities, such as development of the Eko Atlantic construction project. Coastal surveillance, together with the use of environmentally sensitive protective measures, could possibly help to reduce coastal erosion in the region. Careful coastal management practices, including artificial nourishing and the installation of resilient structures (e.g. seawalls), should be undertaken to protect human settlements that are already at risk from sea-level rise.  相似文献   

Trichodesmium erythraeum (Ehrenberg) bloom along the southwest coast of India (Arabian Sea) and its impact on trace metal concentrations in seawater     

Anoop A. Krishnan  P.K. Krishnakumar  M. Rajagopalan 《Estuarine, Coastal and Shelf Science》2007,71(3-4):641-646

The incidence of a large scale Trichodesmium erythraeum bloom along the southwest coast of India (Arabian Sea) observed in May 2005 is reported. Around 4802 filaments of T. erythraeum ml⁻¹ seawater was observed and a colony consisted of 3.6 × 10⁵ cells. The bloom was predominant off Suratkal (12° 59′N and 74° 31′E) with a depth of about 47 m, covering an area of 7 km in length and 2 km width. The concentrations of Zinc, Cadmium, Lead, Copper, Nickel and Cobalt were determined in samples collected from the bloom and non-bloom sites using stripping voltammetry. The observed hydrographical and meteorological parameters were found to be favorable for the bloom. The concentrations of Zinc, Cadmium and Nickel were found to be higher at bloom stations, while the concentrations of Lead, Copper and Cobalt were found to be very low at bloom stations. Elevated concentrations of Cadmium and Cobalt were observed at Valappad mainly due to the decomposition of detrital material produced in the bloom. Statistically significant differences (P > 0.01) in metal concentrations between the bloom and non-bloom stations were not observed except for Copper. Metals such as Lead, Copper and Cobalt were removed from the seawater at all places where bloom was observed. Cadmium was found to be slowly released during the decaying process of the bloom.  相似文献   

黄河三角洲造陆速率对夏季风强度变化和人类活动的响应     

许炯心 《海洋学报》2007,29(5):88-94

以夏季风强度指数和年均气温作为反映气候变化的指数,以人类净引水量和流域水土保持面积作为反映人类活动变化的指标,并以黄河流域为例,研究了三角洲造陆对气候变化和人类活动的响应.研究表明,夏季风强度指数的变化可分为三个阶段:(1)在1951~1963年夏季风强度指数呈持续增强的变化趋势;(2)在1963~1965年夏季风强度指数呈突变式减弱;(3)在1966~2000年夏季风强度指数保持在较低的水平上,且呈缓慢减弱的趋势.年降水量变化与夏季风强度指数有同步关系.从1950到1970年的年均温度在波动中略呈降低趋势,然而从1970年开始年均温度在波动中具有持续上升的趋势.气候变化会导致入海泥沙通量的变化,并可能进一步导致三角洲造陆速率的变化.黄河三角洲造陆速率、入海泥沙通量在1952~1964年均呈增大的趋势,1964年后则呈减小的趋势,在总体上与夏季风强度指数的变化趋势相同.除了气候变化以外,流域水土保持和引水对三角洲造陆也有影响.多元回归分析表明,三角洲造陆速率随夏季风强度指数的减弱而减小,随年气温的升高而减小,随梯田林草面积的增加而减小,随年净引水量的增加而减小,同时还表明,夏季风强度指数、年均气温、水土保持措施面积和人类净引水量对三角洲造陆速率变化的贡献率分别为34.94%,3.80%,53.82%和7.44%.表示气候变化的两个变量的贡献率之和为38.7%,说明气候变化对黄河三角洲造陆过程的影响是不容忽视的.  相似文献