胶体磷在河口区随盐度变化的研究

研究了胶体磷在河口海区随盐度变化的趋势,并将其与颗粒态、真溶解态磷随盐度的变化趋势进行对比,分析胶体态磷在河口的行为与颗粒态磷和真溶解态磷二者的异同。探讨磷在颗粒相、胶体相和真溶液相之间的分配及其与悬浮颗粒物浓度的关系,研究胶体磷在河口海区中的迁移转化作用。研究结果表明,胶体相中总磷、有机磷和活性磷浓度由河端向海端降低,表明陆源输入是其主要来源。胶体有机磷占总磷比例随盐度增加而下降,表明有机磷受胶体去除过程的影响较明显,胶体磷在河口海区的浓度变化趋势及胶体中有机磷和活性磷的比例都与真溶解相接近而与颗粒相差别较大。     

天然胶体中磷的含量及分布

错流超滤(Cross-flow filtration)技术在海洋学上的应用使得海洋胶体的研究日益广泛,它使胶体能够从过去由0.45μm滤膜过滤所得的所谓“溶解”相中被提取出来,独立地进行研究.研究表明[1~5],水体中普遍存在的胶体对于海洋环境中的有机物质、痕量金属和放射性核素的生物地球化学循环具有不容忽视的影响.胶体具有粒径小、比表面积大和富含有机官能团的特性,易吸附一些放射性核素、痕量金属和有机化合物,成为决定海洋中元素的存在形式和迁移过程的重要部分.因此,胶体中无机和有机组分的含量和分布的深入研究有助于进一步了解各种元素的生物地球化学循环过程.     

珠江河口水体有机物与盐度和氮,磷营养盐的关系

根据１９８７年２月至１９８８年２月的调查资料，讨论了珠江河口水域ＣＯＤ与盐度和Ｎ，Ｐ营养盐间的相互关系。线性回归的结果表明，纵断面Ⅲ的丰，枯水期ＣＯＤ与Ｓ和Ｎ，Ｐ间相关性很好，在９９％置信水平上显著，横断面Ⅰ，Ⅱ区间，ＣＯＤ与Ｓ呈岁相关趋势，ＣＯＤ与Ｎ高度显著相关，ＣＯＤ与Ｐ相关性次之。     

海洋中胶体研究的新进展

对近１０年以来胶体研究的报道和进展进行综合评述。Ｃｒｏｓｓ－ｆｌｏｗ超滤技术在海洋学上的应用促进了海洋胶体的进一步研究。研究表明,胶体物质天有机碳、氮、痕量金属、放射性核素及有机污染物的生物地球化学循环中可能起着重要作用。这一领域的研究对重新认识海洋物质循环的各种过程具有深远意义。     

低盐度水体南美白对虾对饲料中钙、磷的需求

低盐度水体中 ,以不同钙、磷含量的试验饲料对南美白对虾 (Penaeus vannamei)幼虾(0 .0 1 79± 0 .0 0 2 8) g进行饲养试验。结果表明 ,饲料钙磷的交互作用对南美白对虾的特定生长率、成活率及饲料系数有显著的影响 (P<0 .0 5 )。饲料中不添加钙、磷 ,南美白对虾幼虾的生长、成活率和饲料系数最差 ;饲料中钙、磷添加量分别为 0 .8%,1 .2 %时 ,南美白对虾生长最好。饲料钙、磷对南美白对虾体组织钙、磷含量存在显著的影响 (P<0 .0 5 )。特定生长率与肌肉 Ca/ P比 ,甲壳厚 /体质量比呈显著负相关关系。     

长江河口径流与盐度的谱分析

根据大通水文站的流量和引水船站的盐度系列资料,应用谱分析方法研究长江口径流、盐度的变化规律及两者的相互关系.分析表明,长江口径流存在4～8a,2～3a,1.5a,1a,30～60d及20d的及化周期;盐度存在5～10a,2～3a,1.5a,1a,0.5a,40～50d,26～30d,14～15d7～8d及3.5d的变化周期.径流和盐度的谱结构在各水文年基本一致,均以1a周期变化占优势,但盐度谱结构在高频部分较径流的谱结构具有更大的振荡.盐度与流量的5～10a,2～3a,1.5a,1a的周期振动上存在高相关.径流对盐度变化的影响主要体现在低频部分.在低频变化中表现为盐度变化滞后于径流变化,在高频带呈同步变化.     

黄河入海径流对河口海域盐度影响研究

为研究黄河入海径流变化条件下河口附近海域盐度扩散特征,以更好地保护河口海域生物资源多样性,本文以黄河下游利津水文站的长序列实测径流数据资料为基础,利用近海水动力模型FVCOM,分析径流变化对黄河口海域盐度的影响规律。结果表明：黄河口与莱州湾之间存在顺时针的环流系统,在余流作用以及涨落潮方向的影响下,黄河冲淡水长期向莱州湾扩散;丰水期黄河冲淡水几乎影响了整个莱州湾,27盐度锋可以到达莱州湾中部,27等盐线的表层包络面积为2 665.61 km²,占莱州湾的1/4左右,枯水期低盐度水只有向南扩散的趋势,27以下的低盐度水集中分布在黄河口门附近,27等盐线的表层包络面积只有199.65 km²;5月份,随着入海径流量增加,27等盐线扩散的范围、距离、方向都会发生明显变化。在对近海生物资源有迫切保护需求的情景下,适当减少其他用水户供水量以增加入海生态径流量,可以有效改善黄河口海域附近的盐度情况,为生物资源的生长繁殖创造良好条件。     

厦门西海域盐度的变化

分析了厦门西海域的盐度,结果表明:其季节变化与厦门地区的降雨量有密切关系。春季,盐度为全年的最低值。厦门西海域盐度的周日变化受潮汐的影响,其最大值和最小值出现在平潮前后1h之内。     

饲料中钙、磷和水体盐度对南美白对虾幼虾生长的影响

用不同钙、磷含量的配合饲料在不同的盐度水体中对南美白对虾幼虾 (Penaeus vannamei)进行饲养试验.试验采取 L9(3 4),磷添加量设 3个水平 0%, 0.75%, 1.5%;钙添加量设 3个水平 0%, 0.75%, 1.5%;水体盐度设 3个水平 4, 17, 30.结果显示,各因素对南美白对虾体质量日增率、饲料系数、成活率的影响大小为盐度 >磷 >钙,对蛋白质效率的影响大小为盐度 >钙 >磷.盐度 4时,不添加钙的组体质量日增率、饲料系数、成活率和蛋白质效率最差;盐度 17时,饲料中磷的添加非常重要.南美白对虾幼虾最适的生长因素是盐度为 17,钙添加量为 1.5%,磷添加量为 1.5%     

两种甲藻对人工海水中胶体磷的利用初探

采用批次培养方法,研究了东海原甲藻(Prorocentrum donghaiense)和链状亚历山大藻(Alexandrium catenlla)对胶体磷的生物可利用性,并初步探讨了甲藻利用胶体磷的机制问题.结果表明东海原甲藻和链状亚历山大藻均能利用胶体磷生长繁殖.东海原甲藻在接种11d后细胞密度在无机磷和胶体磷培养基中分别为10.53×107和3.43×107个/dm3.链状亚历山大藻在接种11d后细胞密度在无机磷和胶体磷培养基中分别为39.0×105和28.3×105个/dm3.通过对比细胞密度,胶体磷对东海原甲藻生长的促进作用要低于无机磷的作用;胶体磷对链状亚历山大藻生长的促进作用与无机磷的作用相当.东海原甲藻和链状亚历山大藻在胶体磷源下碱性磷酸酶活性迅速升高,前期均显著高于各自无机磷组的碱性磷酸酶活性,碱性磷酸酶活力最高值分别为0.29和0.30μmol/(dm3·h).初步结果表明,两种甲藻均能通过碱性磷酸酶的降解来利用胶体磷.     

Study of colloidal phosphorus variation in estuary with salinity

The variation of colloidal phosphorus with salinity in estuary was studied in this paper, which was compared with those of particle and truly dissolved phosphorus with the purpose of ˉnding out the similarities and di?erences between their behaviors in the estuary. Distribution patterns of phospho- rus in particle, colloidal and truly dissolved phase at di?erent salinities and their relationships with suspended particulate matter were also studied to understand the transformation and transporta- tion of colloidal phosphorus in estuarine area. The result showed that the concentrations of total colloidal phosphorus, organic colloidal phosphorus and inorganic colloidall phosphate all descended from river-end to sea-end, illustrating their terrigenous source. Ratios of organic to total colloidal phosphorus decreased with salinity's increment, indicating that organic phosphorus was in°uenced by scavenging process of colloid more signiˉcantly as compared with inorganic phosphate. Both of the phosphorus variation tendencies and the proportion between organic and inorganic phosphorus in colloidal phase was similar with that in truly dissolved phase while di?erent from that in particle phase.     

钱塘江河口盐度数值模拟

强潮河口盐水入侵对饮用水源地危害极大。基于平面二维水动力盐度模型, 对典型强潮河口—钱塘江的水动力及盐水入侵过程进行了数值模拟研究。结果表明枯水径流时盐度变化与潮位过程曲线类似, 潮差对盐度大小影响显著, 径流量的增加将逐渐减小其相似程度。当流量增加到一定程度后, 继续增加的一定径流量所产生的抑咸效果减弱, 水资源有效利用率降低, 此时允许水源地盐度超标并改从蓄淡避咸水库取水可有效节约水资源。盐度平面分布显示, 盐水入侵在强潮河口弯道处受涨潮流主流线影响明显, 靠近主流线一岸的盐度大于对岸, 单从盐水入侵角度考虑, 强潮河口弯道段的取水口应设置在远离涨潮流主流线一岸。钱塘江河口盐度数值模拟对于研究减轻盐水入侵对水源地危害的措施具有指导意义。     

Modeling of circulation and salinity in Hooghly estuary

The circulation and salinity distribution in the Hooghly Estuary have been studied by developing a two‐dimensional depth‐averaged numerical model for the lower estuary, where the flow is vertically well mixed. This has been coupled with a one‐dimensional model for the upper estuary, where the flow is assumed to be unidirectional and well mixed over the depth and breadth. The Hooghly River receives high freshwater discharge during the monsoon season (June to September), which has significant effect on the salinity distribution in the estuary. The model‐simulated currents, elevations, and salinities are in good agreement with observations during the dry season. However, during the wet season the computed salinities seem to deviate slightly from the observed values.     

Freshwater phytoplankton in the low salinity region of the River Tamar estuary

An investigation was made into the fate of freshwater algae in the Tamar estuary, south-west England, to examine the hypothesis that oxygen minima, observed at the freshwater-brackish water interface, were a consequence of mass mortality of freshwater algae and the subsequent oxidative degradation of the lysed cells by bacteria. The quantity and species composition of algae in the river and estuary were determined by measurements of chlorophyll and cell numbers. Phytoplankton numbers were transformed into biomass by measuring the volume of the cells and calculating the carbon content. Salinity, dissolved oxygen, turbidity, pH and temperature were also recorded. The size of the upper estuarine community was inversely related to freshwater input. During the summer months, very large populations of freshwater algae (up to 8 mg carbon l⁻¹) were observed between 0 and 8‰ salinity, after long periods of low freshwater input. This population was completely dominated by the diatom Cyclotella atomus and was very stable with respect to changing tides, remaining in the estuary until river flow increased. Death of these algae only occurred at salinities greater than 8‰ and oxygen minima were not observed. The oxygen minima were more closely associated with the turbidity maxima than with algal mortality. There is some evidence that the oxygen depletion may be due to decreased photosynthesis as a result of the reduced light availability at the turbidity maxima.     

A note on turbulent perturbations of salinity in a partially mixed estuary

Measurements of salinity perturbations in a partially mixed estuary have been used to evaluate the usefulness of an inductive salinometer and to determine some of the characteristics of the salinity perturbations. The salinometer performed satisfactorily under most conditions. Although internal wave like effects were present, the turbulence fluctuations were dominant. The salinity fluctuations and the turbulent fluxes $\text{sw}$ and $\text{su}$ were found to behave in a manner similar to the density fluctuations in a thermally stratified atmospheric boundary layer and a laboratory open channel flow. A quadrant analysis suggested that the contribution of each quadrant to the turbulent flux changed with Ri. The turbulence parameters ν and c_γ were found to decrease and increase respectively as Ri increases.     

九龙江口秋茄红树林恢复对底质磷的影响

以光滩为对照,分别在白礁选取5、6、8a生秋茄(Kandelia candel)人工林以及天然秋茄林为样地,在草埔头选取20a生和44a生秋茄人工林为样地,比较分析了福建九龙江口秋茄红树林恢复对底质总磷和有效磷的影响.结果表明:白礁和草埔头秋茄人工红树林的总磷和有效磷含量随红树林恢复时间的增加而增高.白礁天然秋茄林和草埔头秋茄人工林的总磷随底质深度增加而减少,有效磷在中下层含量较高.潮位对草埔头总磷有显著影响,由外滩到内滩,其总磷含量逐渐增加.九龙江口秋茄红树林早期恢复阶段的底质总磷和有效磷缺乏,5a生秋茄人工林底质总磷和有效磷分别为0.68g/kg和2.99mg/kg.     

Annual variation in the nocturnal nekton assemblage of a tropical estuary

A nocturnal demersal nekton assemblage was sampled fortnightly for two years at five sites in the Labu estuary using a 3-m beam trawl with a 3·2-cm mesh net. Forty species were caught, totalling 31458 individuals with the five most abundant species comprising over 95% of the catch. Using multiple regression techniques with Fourier transformations, the mean number of species (S), the mean abundance (N), and mean weight (W) were found to conform to a regular annual cycle with maxima in April and May. Seven of the 11 most abundant species demonstrated regular annual cycles of abundance. S, N and W were greatest in the wider, middle sites and lowest in a shallow, stagnant side branch of the estuary. Catch weights and abundances were significantly correlated with physical data.Salinity and temperature values in the estuary exhibited an annual cycle with maxima occurring in February-March. The annual thermal variation of surface water outside the estuary followed a similar cycle. The salinity at the mouth of the Markham River is lowest during January-February, which corresponds with the rainy season in the Markham River catchment. Significant annual variation existed between years in estuarine bottom salinity values in Labu Bay.Several species exhibited a greater variation in abundance and mass between years than within years. This supports the hypothesis that in the tropics between-year variation in coastal marine biotic communities is greater than within-year variation.     

Annual variation in the nocturnal nekton assemblage of a tropical estuary

A nocturnal demersal nekton assemblage was sampled fortnightly for two years at five sites in the Labu estuary using a 3 m beam trawl with a 3·2 cm mesh net. Forty-eight species were caught, totalling 31 458 individuals with the five most abundant species comprising over 95% of the catch. Using multiple regression techniques with Fourier transformations, the mean number of species, S, the mean abundance, N, and mean weight, W, were found to conform to a regular annual cycle with maxima in April and May. Seven of the 11 most abundant species demonstrated regular annual cycles of abundance. S, N and W were greatest in the wider, middle sites and lowest in a shallow, stagnant side branch of the estuary. Catch weights and abundances were significantly correlated with physical data.Salinity and temperature values in the estuary exhibited an annual cycle with maxima occurring in February/March. The annual thermal variation of surface water outside the estuary followed a similar cycle. The salinity at the mouth of the Markham River is lowest during January/February, which corresponds with the rainy season in the Markham River catchment. Significant annual variation existed between years in estuarine bottom salinity and salinity values in Labu Bay.Several species exhibited a greater variation in abundance and mass between years than within years. This supports the hypothesis that in the tropics between-year variation in coastal marine biotic communities is greater than within-year variation.