排序方式： 共有52条查询结果，搜索用时 15 毫秒
41.
对4株红螺菌(荚膜红假单胞菌PSB-2、球形红假单胞菌PSB-3、胶质红假单胞菌H1和沼泽红假单胞菌H10)的去细胞上清液(CFS)抑制水产养殖病原菌的作用进行研究,并探讨养殖水体环境对红螺菌拮抗作用的影响.结果表明,4株红螺菌在细胞生长稳定期后能有效分泌拮抗物质,其去细胞上清液(CFS)对20多株水产养殖病原菌均有抑制作用.从抑菌活性看,荚膜红假单胞菌的抑菌活性强于其他菌株:荚膜红假单胞菌对水产养殖病原菌的最低抑菌浓度(MIC)为8～64 AU/mL,而其他红螺菌株多为4～16 AU/mL.在养殖水体的生态因子中,水体pH、NH4 -N与NO2--N对红螺菌代谢产物的抑菌活性影响较大,pH7～9,NH4 -N低于5 mg/L、NO2--N浓度低于7mg/L时抑菌活性较强,而养殖水体温度与溶氧变化对红螺菌的抑菌活性基本无影响作用. 相似文献
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以基于人工鱼礁为构建主体的大亚湾海洋牧场为研究实例,以2007年4月和2009年5月调查数据为基础,研究了海洋牧场在资源养护和提高海域碳汇能力等方面的作用。结果表明,人工鱼礁型海洋牧场建设提高了海域浮游生物和底栖生物的栖息密度以及渔业资源的数量和质量,底栖生物和游泳生物的生物多样性指数增加,渔业资源优势种中的优质经济鱼类的数量增加。根据海域叶绿素浓度的提高进行计算,海洋牧场建设使海域碳汇增加了937.40kgC,相当于3.44tCO2。如果同时考虑通过渔业生物收获从海域中移出碳而增加的海域碳汇能力,则其起到的海域碳增汇能力将更高。本研究的结果表明,海洋牧场是一种环境友好型、可持续发展的低碳渔业生产模式,有利于水生生物资源养护和增殖,也是生物碳汇扩增的科学途径。 相似文献
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在室内半静水的试验条件下,应用实时荧光定量PCR技术研究了不同质量浓度（0μg·L-1、5μg·L-1、10μg·L-1、50μg·L-1和100μg·L-1）的0。柴油水溶液（WSF）胁迫15d和清洁海水恢复7d中翡翠贻贝（Pernaviridis）外套膜与内脏团组织中CYP4基因的相对表达水平变化。2-△△Ct法分析结果表明,CYPd基因在翡翠贻贝外套膜和内脏团中均有表达,WSF胁迫对其表达水平有明显的诱导作用,且表达水平具有组织差异性;内脏团表达水平明显高于外套膜,两组织CYP4基因相对表达水平随着WSF胁迫时间的延长,整体呈现出先诱导后抑制再诱导的波动变化趋势,其中50μg·L-1浓度组表现最为显著（P〈0．01）。WSF胁迫解除后外套膜与内脏团CYP4基因相对表达水平迅速下降,部分浓度组逐渐恢复到正常水平。 相似文献
44.
南海北部陆架斜坡海域夏季浮游动物群落的空间分布 总被引：1，自引：0，他引：1
根据2015年7-8月南海北部陆架斜坡海域的浮游动物垂直分层采集资料,对该海域浮游动物的种类组成、优势种、丰度和生物量及群落结构的空间分布等进行了研究。样品利用Multinet浮游生物连续采样网采自0~200 m,200~350 m,350~450 m,450~600 m,600~750 m等5层。该次调查共发现浮游动物468种(类),其中以0~200 m水层种类最丰富,600~750 m水层最贫乏,种类数总体随水深的增加而减少,但在350~600 m水层部分站位出现了回升。浮游动物种类组成垂直变化较明显,各水层均有出现89种共有种,占总种类数的19.02%;而单一水层出现的特有种(121种)占总种类数的25.85%。优势种有10种,角突隆剑水蚤(Oncaea conifera)为各水层的共有优势种,在不同水层还出现了特有优势种。浮游动物丰度和生物量平均为62.79个·m~(-3)和34.81 mg·m~(-3),总体呈现由表层向深层逐渐递减的分布趋势,但在350~600 m水层大部分站位也略有回升。聚类分析结果表明,该调查海域浮游动物大体分为3个群落,分别为0~200 m的上层水域群落、200~450 m的中上层水域群落和450~750 m的中下层水域群落。 相似文献
45.
陆坡是陆架到深海的过渡区域,具有独特的地理生态环境特征,能量和物质交换活跃。为了解南海北部陆坡海域生态系统状况,实验根据2015—2016年南海北部陆坡海域渔业资源和海洋生态调查数据,利用Ecopath with Ecosim 6.5(EwE6.5)软件构建了由22个功能组组成的南海北部陆坡海域生态通道模型,分析了该海域生态系统营养结构、能量流动及生态系统总特征。结果显示,南海北部陆坡生态系统各功能组营养级范围为1.00～4.47,海豚占据了最高的生态位。关键度指数(KSI)分析表明,中型浮游动物、鸢乌贼为南海陆坡生态系统的关键种。生态系统中能量流动主要以碎屑食物链为主,能量来源于碎屑的比例为52%。生态网络分析表明,系统能量主要分布在6个整合营养级,来源于初级生产者和碎屑的转化效率分别为21.26%和22.39%,系统平均转化效率21.94%。研究表明,南海陆坡海域生态系统具有较高的生态转化效率。 相似文献
46.
我国赤潮频发现象分析与海藻栽培生物修复作用 总被引：11，自引：1，他引：11
In this paper, the history, main events and present status of red tide
(HAB, harmful algal blooms) along China coast in recent years were reviewed and presented. It showed that the HAB's frequency and scale, number of HAB spec
ies, percentage of toxic HAB events and the degree of damages to marine environment and economy have sharply increased in China since 1960's.
Eutrophication was key factor for high occurrence of red tide. In this paper, main causes of frequent HAB occurrence along China coast was discussed. Many factors might influence the occurrence of red tide, which included weather, climate, coastal current, tidal current, water temperature, salinity, hydrodynamic and nutrient conditions, trace metals and the variation of biological environment. Numerous evidences from all over the world revealed the linkage between the increases in nutrient loading and the occurrences of high biomass blooms. Eutrophication was one of the important causes that involved in high occurrence of HAB. The main sources of nutrients potentially stimulating HABs included terrestrial runoff, aquaculture selfpollution, atmospheric deposition, sea projects and other pollution events in the ocean. Studies showed that the input from land contaminations and the selfpollution of marine aquaculture accelerated eutrophication in coastal waters and were also important impact factors on red tide. Researches suggested that nutrient composition could affect the species composition of phytoplankton as well as the development of some HABs. The changes in nutrient supply ratios, primarily N∶P, often resulted in shifts in red tide species composition. The correlation between cysts and formation of HAB was discussed from the viewpoi
nt of transformation of cyst and vegetative cell, the effects of trace elements and other organic substances on the occurrence of HAB were presented also. It indicated that the nutrient control could be an effective way to reduce the risk of red tide occurrence. Seaweed would play an important role for decreasing marine eutrophication. Among the different methods of red tide controlling studied, seaweed biomass has received much attention due to the cost saving, low sensitivity to environmental and impurity factors, the possible contaminant recovery from the biomaterial and its elevated adsorption capacity. Cultivated seaweeds have very high rates of productivity higher than that of seaweed in its natural habits and grow well in water bodies with higher nitrogen and other nutrients. Seaweeds are able to absorb large quantities of nitrogen, phosphorus and carbon dioxide, produce large quanti
ties of oxygen, and have excellent effect on decreasing eutrophication. Large amounts of C, N and P are accumulated into seaweed tissues as they accumulate considerable biomass over a period of months or years depending on the cultivation season. When seaweeds are harvested, nutrients are removed from the sea area. An investigation was carried out for inorganic nitrogen and inorganic phosphorus concentration at Lusi Coast, Qidong County, Jiangsu Province in China, where there were about 270 hm2 for Porphyra yezoensis cultivation with eutrophic sea water in recent years. While during Porphyra yezoensis cultivation, from Sep 2003 to May 2004, the concentration of ammonium nitrogen declined form 0.511-0.778 mg·L-1 to 0.006-0.057 mg·L-1, nitrite nitrogen concentration declined from 0.010-0.040 mg·L-1 to 0.001-0.009 mg·L-1, and nitrate nitrogen concentration declined from 0.466-0.549 mg·L-1 to 0.286-0.0568 mg·L-1, the average concentration of inorganic phosphorus declined from 0.024 mg·L-1 to 0.019 mg·L-1. Furthermore, during five hours, the concentration of ammonium nitrogen in the seawater declined form 220.88 μmol·L-1 to 8.59 μmol·L-1 by cultivated Gracilaria lemanaiformis, and the concentration of ammonium nitrogen declined form 213.84 μmol·L-1 to zero by cultivated Enteromorpha clathrata. Other bioremediation mechanisms of seaweed inhibiting the red tide microalgae such as nutrients competition and allelopathic effects were also discussed. 相似文献
47.
48.
耐盐红螺菌科细菌对淡水鱼池水质及细菌类群的影响 总被引：19，自引：4，他引：19
对耐盐红螺菌科光合细菌应用于淡水斑点叉尾Hui、彭泽卿养殖后，水化学环境因子、细菌类群及养殖生物的变化进行了研究。结果表明，鱼池泼施光合细菌后，水体NH4^ -N、NO2^--N、NO3^--N和COD下降，溶氧和pH上升；细菌类群及数量变化大致是：光合细菌提高3－50倍（多数在15－20倍）, 硝酸细菌提高3倍，硝酸细菌提高4－5倍；斑点叉尾Hui养殖池的主要异养细菌肠杆菌科细菌提高9．4％，气单胞菌属降低7．5％，彭泽鲫养殖池的主要异养细菌假单胞菌属降低16％，肠杆菌科提高21％；养殖生物的养殖效果是：斑点叉尾Hui鱼苗个体增重提高15．7％，彭泽卿苗个体增重提高12．8％。 相似文献
49.
竹荚鱼(Trachurusjaponicus)是中国南海北部近海主要渔获物之一,其空间分布具有非均匀性。根据2014—2017年南海北部近海两个周期(2014—2015年为第1周期, 2016—2017年为第2周期)的底拖网调查数据,以单位捕捞努力量(catchperuniteffort,CPUE)表征资源密度,采用柯尔莫可洛夫-斯米洛夫检验(Kolmogorov-Smirnov,K-S test)探索了11种概率分布特征。结果表明,南海北部陆架区竹荚鱼不具明显的概率分布特征,而北部湾海域竹荚鱼资源密度服从对数正态分布型且第二周期较第一周期更为显著。同时,采用基于对数正态理论模型法(对数正态模型与Delta模型)与调查设计法(均值法)对该海域进行资源密度估值比较,发现基于对数正态理论模型更切合竹荚鱼资源密度结构分布特征,而在对数正态理论模型中Delta模型法更适用于该物种资源密度估值。 相似文献
50.
为了解生境差异显著的华南典型海湾主要渔业生物的营养结构特征,于2015年丰水期研究了海陵湾和陵水湾主要渔业生物碳、氮稳定同位素比值(δ~(13)C和δ~(15)N),并计算了基于δ~(13)C-δ~(15)N量化的营养结构。结果表明,海陵湾主要渔业生物的δ~(13)C [(-15.36±0.62)‰]和δ~(15)N [(15.53±0.94)‰]均显著高于陵水湾(P0.01),但δ~(13)C差值(CR)和δ~(15)N差值(NR)低于陵水湾。陵水湾渔业生物NR和总面积(TA)都高于海陵湾,表明陵水湾比海陵湾食物链更长,多样性水平更高。以3.4‰作为一个营养级的氮稳定同位素富集度来计算,陵水湾渔业生物营养级级距仅为1.37,而海陵湾主要渔业生物营养级级距小于1,说明陵水湾和海陵湾均处于高营养级生物较少且食物网受干扰较多的状态。 相似文献