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《Marine Chemistry》2007,103(1-2):61-75
The capacity of natural dissolved organic matter (DOM) produced during the onset, development and decay of a simulated bloom of the marine diatom Skeletonema costatum to complex free copper has been followed for a 2 week period. Copper binding capacity of the culture was measured by anodic stripping voltammetry (ASV) with a hanging mercury drop electrode (HMDE). The concentration of dissolved organic carbon (DOC) and two fluorophores, M (humic-like, Ex/Em: 320 nm/410 nm) and T (protein-like, Ex/Em: 280 nm/350 nm), were followed during the course of the incubation. Models using DOC concentrations alone could not accurately predict the complexing capacity of the culture, especially at the end of the bloom, and better predictions were obtained when fluorescence measurements were considered. They were helpful in characterising two types of copper ligands produced in the culture. The first type, traced by the fluorescence of peak T, was related to labile DOC directly exuded by phytoplankton. The second type, traced by the fluorescence of peak M, was the refractory humic-like material presumably produced in situ as a by-product of the bacterial degradation of phytogenic materials. During the onset and development of the bloom (days 0 to 7), the fluorescence of peak T explains 60–80% of the total complexing capacity of the culture, suggesting that exuded “protein-like” compounds among other exuded complexing agents efficiently complexed free copper. On the contrary, during the decay (days 8 to 13), these ligands were replaced by humic substances as the complexing agent for copper. 相似文献
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对广东大亚湾海域1997年7月至1998年6月期间中肋骨条藻Skeletonema costatum种群动态及其与环境因子之间的关系进行研究.结果表明,中肋骨条藻在该海湾全年出现,有春季与秋季两个藻细胞密度高峰期,其中秋季时的藻密度最大.1998年4-6月密集采样期间,各站位中肋骨条藻种群数量变动基本上呈现出表层密度高于底层的趋势,各站位间的数量变动具有一定的空间差异,呈现出养殖区、生活区等近岸海域藻细胞密度高于远岸海域的趋势.中肋骨条藻高频率、高密度出现的温度范围为25-26℃,盐度范围为30.6‰-31.6‰,溶解性无机氮 (dissolved inorganic nitrogen,DIN)、可溶性无机磷 (dissolved inorganic phosphorus,DIP)和SiO32--Si范围分别为9.2-78.3、3.7-5.9和564.0-1054.6μg·L-1.相关性分析表明,影响大亚湾海域中肋骨条藻种群数量的主要环境因子有SiO32--Si、DIN、化学需氧量 (chemical oxygen demand,COD)和氮磷比值,同时水温、溶解氧 (dissolved oxygen,DO)也在一定程度上影响着中肋骨条藻的种群动态. 相似文献
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Using the SAS software, the data of environmental factors vs. red tide biomass were analysed during the process of Skeletonema costatum red tide which broke out in the Changjiang Estuary on June 9~15, 1990. The results of the multivariate statistical analysis show that the environmental factors are similar in their developing and maintenance periods and that the values of environmental factors begin to be restored to normal levels during the disappearing period.The results obtained from using the methods of correlation, variable cluster and main component analyses are basically identical. The important factors contributing to the occurrence of this red tide are atmospherical pressure, water temperature, salinity, pH, No3-, -N, Po43--P and Fe, among which,salinity, Fe and PO43--P are the leading factors which have triggered the occurrence of the red tide as determined by the step-by-step regression analysis. Meanwhile, the linear discrimination functions have been established for the red tide. The environmental factor data of another occurring process of Skeletonema costatum red tide in the Changjiang Estuary have been chosen for red tide discrimination with satisfactory results. 相似文献
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The relationship between the spring bloom along the Primorye coast and the sea ice of the Tatarskiy Strait in the northern region of the East/Japan Sea, a semi-enclosed marginal sea in the North Pacific, was investigated using the ten-year SeaWiFS chlorophyll-a concentration data and DMSP/SSMI sea ice concentration data from 1998 to 2007. Year-to-year variations in the chlorophyll-a concentrations in the spring were positively correlated with those of the sea ice concentrations in the Tatarskiy Strait in the previous winter with a correlation coefficient of 0.77. Abrupt increases in nutrients, essential for the spring bloom in the upper ocean during spring, were supplied from sea ice-melted waters. Time series of vertical distributions of the nutrients indicated that phosphate concentrations were extremely elevated in the upper ocean (less than 100 m) without any connection to high concentrations in the deep waters below. The water mass from sea ice provided preferable conditions for the spring bloom through changes in the vertical stratification structure of the water columns. Along-coast ratios of stability parameters between two neighboring months clearly showed the rapid progression of the generation of a shallow pycnocline due to fresh water originating from sea ice. This study addressed the importance of the physical environment for biogeochemical processes in semi-enclosed marginal seas affected by local sea ice. 相似文献
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半连续培养下东海原甲藻和中肋骨条藻种群生长过程与种间竞争研究 总被引:17,自引:0,他引:17
采用半连续培养方法研究了温度和营养盐(N和P)限制对中国东海2种重要赤潮生物东海原甲藻和中肋骨条藻生长及种间竞争的影响。结果表明,东海原甲藻在20℃和25℃时生长状态良好,具有明显的指数增长期,15℃时细胞生长明显受到影响;中肋骨条藻具有较广的温度适应性,15~25℃时均具有明显的指数增长期。东海原甲藻可以忍受低营养盐环境并种群增长,而中肋骨条藻细胞增长需要较丰富的营养盐。在营养盐充足的环境里中肋骨条藻具有竞争优势,相反,在营养盐限制的环境中,东海原甲藻是竞争的优胜者。实验结果与东海原甲藻赤潮爆发现场的环境调查结果基本一致,可以作为解释东海原甲藻赤潮形成原因的依据。 相似文献
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LED单色光谱及复合光谱对赤潮优势种中肋骨条藻生长的作用 总被引:1,自引:0,他引:1
以赤潮优势种中肋骨条藻(Skeletonema costatum)为研究对象,荧光灯和自制LED(light-emitting diode)控制灯为光源,研究不同LED单色光谱及复合光谱(蓝光,绿光,红光,白光,蓝红光,绿红光)对中肋骨条藻生长的作用。实验结果表明,在相同的光合有效量子通量密度条件下,对于单色光,中肋骨条藻在蓝光下生长较快,红光次之,在绿光下生长最慢;对于复合光,中肋骨条藻在荧光灯下生长最快,而在蓝红光下生长略高于在绿红光下生长。各光源下中肋骨条藻生长速率的顺序为:荧光灯>蓝红光LED>绿红光LED>蓝光LED>红光LED>绿光LED。通过比较在不同光照条件下中肋骨条藻的生长速率,表明不同光谱对中肋骨条藻生长的作用不同。 相似文献
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海洋酸化是当前一个严重的环境问题,而海水pH的变化与微藻生长时对溶解无机碳的吸收有关。在室内条件下采用生理生态学方法,研究中肋骨条藻Skeletonema costatum和三角褐指藻Phaeodactylum tricornutum在不同无机氮水平下生长到最大生物量时培养液pH的变化。结果表明,培养液无机氮浓度从10μmol.L-1上升到200μmol.L-1过程中,2种微藻的叶绿素浓度和最终pH均呈上升趋势。培养液pH的增加量与无机氮的消耗量呈正相关关系,培养液pH的增加量与溶解无机碳的消耗量也呈正相关关系。 相似文献
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Dilution experiments were conducted to investigate microzooplankton grazing impact on phytoplankton of different taxonomic groups and size fractions (< 5, 5–20, 20–200 μm) during spring and summer bloom periods at two different sites (inner Tolo Harbour and Tolo Channel) in the Tolo Harbour area, the northeastern coastal area of Hong Kong. Experiments combined with HPLC pigment analysis in three phytoplankton size fractions measured pigment and size specific phytoplankton growth rates and microzooplankton grazing rates. Pigment-specific phytoplankton growth rates ranged between 0.08 and 3.53 d− 1, while specific grazing rates of microzooplankton ranged between 0.07 and 2.82 d− 1. Highest specific rates of phytoplankton growth and microzooplankton grazing were both measured in fucoxanthin in 5–20 μm size fraction in inner Tolo Harbour in summer, which coincided with the occurrence of diatom bloom. Results showed significant correlations between phytoplankton growth and microzooplankton grazing rates. Microzooplankton placed high grazing pressure on phytoplankton community. High microzooplankton grazing impact on alloxanthin (2.63–5.13) suggested strong selection toward cryptophytes. Our results provided no evidence for size selective grazing on phytoplankton by microzooplankton. 相似文献
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为研究北部湾地区海砂填料的动力特性,采用高级动态三轴测试系统开展循环荷载下的动三轴试验,研究不同围压及不同动应力幅值对海砂动力特性的影响规律。试验结果表明:轴向累计应变随围压增加而减小,围压150 kPa时振次10 000后应变仅为3%;随着动应力幅值的增大轴向累积应变随之增大,且达到破坏标准的时间越短。动弹性模量随着动应力幅值和围压的增加而增大,不同围压下动弹性模量随动应变的增加出现先骤减再略减后稳定的发展趋势,εd>0.3%后开始趋于稳定;不同动应力幅值下动弹性模量出现先增后减直至稳定的趋势,其中动应力幅值对动弹性模量有明显的影响,围压影响相对较小。孔压比随动应力幅值增加而减小,随围压增加而增加。 相似文献
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《Ocean & Coastal Management》2008,51(5):405-409
It is shown that low dispute costs relative to expected resource rents from oceanic resources favor drawn out disputes over maritime boundaries; asymmetric dispute costs favor agreement on boundaries wanted by the low dispute cost state party; and high symmetric dispute costs favor formation of joint development zones (JDZs). The fact that most maritime boundaries have not yet been drawn suggests that state parties think that resource rents that can be drawn from the oceans are high relative to dispute costs. Moreover, the recent mini-trend towards JDZs in East Asia suggests that state parties in the area have recently reassessed dispute costs as being higher than previously believed. 相似文献
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2016年8月(夏季)、10月(秋季)和2017年1月(冬季)、5月(春季)于厦门海域开展的4次水质调查,探讨了该海域尿素的时空分布特征及其环境影响因素。结果表明:厦门海域表层尿素态氮平均含量表现为夏季春季秋季冬季,其值分别为3. 06±1. 09、2. 64±0. 82、2. 30±1. 43、1. 67±0. 79μmol/dm~3。底层尿素态氮平均含量表现为春季夏季秋季冬季,其值分别为3. 13±0. 95、2. 70±1. 25、1. 65±0. 80、1. 56±0. 88μmol/dm~3。厦门海域尿素分布总体呈现出河口、内湾高于外部海域的分布格局;由厦门海域尿素含量的时空分布特征及其与环境要素相关性分析结果表明,厦门海域尿素的时空分布不仅受陆地径流输入和陆源排污的影响,还有可能受到海水养殖、海洋生物活动以及潮流的影响,这些影响因素共同调控着厦门海域尿素的时空分布格局。在春季,尿素是厦门海域可利用氮源的重要组成成分,尤其是在大嶝海域。 相似文献
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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
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根据 2 0 0 1年 2月和 7月对崎岖列岛附近海域的水质和底质表层沉积物调查结果 ,采用环境质量单项评价标准指数法 ,对该海域环境质量现状进行了评价与分析。结果表明 :(1 )该海域水质的 p H值、溶解氧和石油类等环境因子基本符合一类海水水质标准 ,化学需氧量、活性磷酸盐和无机氮浓度则超标严重 ,该海域水质已处于严重富营养化状态 (夏季比冬季富营养化程度略低 ) ;(2 )该海域底质表层沉积物中除部分站位的重金属 Cu、 Zn含量超标外 ,有机质、石油类和重金属 Pb、 Cd、 Hg的含量均未超标 ,底质环境状况尚好 相似文献