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1.
The effects on ethoxyresorufin O-deethylase （EROD）, NADPH-cytochrome c reductase and NADH cytochrorne b5 reductase activities of digestive gland in Meretrix meretrix exposed to tributyltin （TBT） at environmental levels （0.1,1.0,10.0 ng/dm as stannum concentration）,in experimental condition, were evaluated. The EROD, NADH cytochrorne b5 reductase activities were significantly inhibited after exposure to 10.0 ng/dm^3 TBT for 8 and 20 d, the NADPH cytochrorne c reductase activities were significantly inhibited after exposure to 0.1,1.0 and 10.0 ng/dm TBT for 8 d and to 1.0 and 10.0 ng/dm for 20 d, as compared with the matched control, while NADH cytochrorne b5 reductases and NADPH cytochrome c reductase activities were induced after exposure to 10.0 ng/dm^3 TBT for 2 d. The EROD activity in the 10 ng/dm^3 group,and the NADH cytochrome b5 reductases activities in 1.0 and 10.0 ng/dm groups, were significantly induced when transferred to clean recovery tanks for 7 d. The three enzymic activities in the clams exposed to TBT were recovered to the level corresponding to that of the control group after transfer to clean recovery tanks for 20 d. NADPH cytochrome c reductase activity in Meretrix meretrix seems to be more sensitive to exposure of TBT than that of the EROD and NADH cytochrome b5 reductases. The results suggest that induction and inhibition by TBT to the monooxygenase system enzymic activity in Meretrix meretrix would simultaneously exist. The enzymic activities were inhibited by exposure for a long time. The results suggest that inhibition of the monooxygenase system should be an indication of the exposure to environmentally relevant concentrations of TBT for a long time.  相似文献   

2.
The effects on ethoxyresorufin O-deethylase (EROD), NADPH-cytochrome c reductase and NADH cytochrome b5 reductase activities of digestive gland in Meretrix meretrix exposed to tributyltin (TBT) at environmental levels (0.1,1.0, 10.0 ng/dm3 as stannum concentration), in experimental condition, were evaluated. The EROD, NADH cytochrome b5 reductase activities were significantly inhibited after exposure to 10.0 ng/dm3 TBT for 8 and 20 d, the NADPH cytochrome c reductase activities were significantly inhibited after exposure to 0.1,1.0 and 10.0 ng/dm3 TBT for 8 d and to 1.0 and 10.0 ng/dm3 for 20 d, as compared with the matched control, while NADH cytochrome b5 reductases and NADPH cytochrome c reductase activities were induced after exposure to 10.0 ng/dm3 TBT for 2 d. The EROD activity in the 10 ng/dm3 group, and the NADH cytochrome b5 reductases activities in 1.0 and 10.0 ng/dm3 groups, were significantly induced when transferred to clean recovery tanks for 7 d. The three enzymic activities in the clams exposed to TBT were recovered to the level corresponding to that of the control group after transfer to clean recovery tanks for 20 d. NADPH cytochrome c reductase activity in Meretrix meretrix seems to be more sensitive to exposure of TBT than that of the EROD and NADH cytochrome b5 reductases. The results suggest that induction and inhibition by TBT to the monooxygenase system enzymic activity in Meretrix meretrix would simultaneously exist. The enzymic activities were inhibited by exposure for a long time. The results suggest that inhibition of the monooxygenase system should be an indication of the exposure to environmentally relevant concentrations of TBT for a long time.  相似文献   

3.
The e?ect of the bacterial strain CI4 on the germination of spores from the green alga Ulva pertusa was assayed and it was found that the bacterial bioˉlm and cell-free supernatant strongly inhibited spore germination. In attempts to deˉne the chemical nature of the antifouling substance in the supernatant of CI4, the culture supernatants were tested for activity after heat treatment, enzy- matic treatments, size fractionation, and separation into aqueous and organic fractions. Results suggest that this bacterium produces an extracellular component with speciˉc activity toward algal spores that was heat-sensitive and between 3 and 10 kDa in molecular size. The exposure of the organic phase fraction to spores showed inhibitive e?ect on spore germination. Pronase and car- boxypeptidase y did not signiˉcantly a?ect the activity of inhibitory component, suggesting that the component was not a protein or a peptide. The bacterium CI4 was identiˉed as Pseudoalteromonas haloplanktis based on the phenotypic characters and 16S rRNA gene analysis.  相似文献   

4.
Numerous studies have been undertaken to improve the viability, durability and suitability of materials and methods used for aquaculture enclosures. While many of the previous studies considered macro-deformation of nets, there is a paucity of information on netting micro-deformation. When aquaculture pens are towed, industry operators have observed the motion described as "baffling" – the transverse oscillation of the net planes parallel and near parallel to the flow. The difficulty to observe and assess baffling motion in a controlled experimental environment is to sufficiently reproduce netting boundary conditions and the flow environment experienced at sea. The focus of the present study was to develop and assess experimental methods for visualisation and quantification of these transverse oscillations. Four netrig configurations with varied boundary conditions and model-netting properties were tested in a flume tank. While the Reynolds number was not equivalent to full-scale, usage of the pliable and fine mesh model netting that enabled baffling to develop at low flow velocities was deemed to be of a larger relevance to this initial study. Baffling was observed in the testing frame that constrained the net sheet on the leading edge, similarly to a flag attachment onto a pole. Baffling motion increased the hydrodynamic drag of the net by 35%–58% when compared to the previously developed formula for taut net sheets aligned parallel to the flow. Furthermore, it was found that the drag due to baffling decreased with the increasing velocity over the studied Reynolds numbers(below 200); and the drag coefficient was non-linear for Reynolds numbers below 120. It is hypothesised that baffling motion is initially propagated by vortex shedding of the netting twine which causes the netting to oscillate; there after the restoring force causes unstable pressure differences on each side of the netting which excites the amplitude of the netting oscillations.  相似文献   

5.
—On the basis of a comparison of the field hydrological,sediment and topographic data observedbefore and after the completion of the West Breakwater in Lianyungang Harbor,which has led to the changeof topography from a strait to a bay,a synthetical analysis is conducted on the change of back siltation.Theresults show that it is the change of coast line and the consequent change of hydrological condition and sedi-ment movement that has led to the change of back siltation in the harbor.This phenomenon is caused by thelag effects of water current,sediment movement and local adjustment of topography after the construction,and it tends to be stable.The results of analysis provide not only a basis for extension of Lianyungang Harborinto a deep water harbor,but also propose a case for the study of the change of back siltation in a harbor onmuddy coast.  相似文献   

6.
Evolution history and trend of the modern Huanghe River Delta   总被引：3，自引：1，他引：2  
The evolvement history of modern Huanghe River Delta tidal flat, coastline and underwater terrain were studied based on the analysis of remote sensing images and water depth data. Based on the analysis of seafloor terrain evolution on different historical stages, a formula simulating the erosion and deposition evolvement model of subaqueous Huanghe River Delta slope was proposed, and the evolvement trend of the subaqueous delta terrain was predicted. The result shows that the equilibrium transition zone is near the water depth of 12 m with seabed erosion in shallower water and accumulation in deeper water during the first 150 a after the river channel was deserted. In the meantime, the underwater slope became gentler and the coastal erosion rate became slow gradually. Then, the subaqueous delta slope changed to up concave from upper convex, and the shape of subaqueous delta disappeared. The coast type changed to silt-mud coast about 100-150 a after the river course was deserted. The erosion depth in the foot of the seawall is calculated based on the formula.  相似文献   

7.
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8.
By use of bathymetric chart,recent change of the riverbed in the North Passage of the Yangtze Estuary has been studied in this paper.The main channel of the upper,middle and lower(section)in the North Passage has been successively eroded and its groin field significantly deposited.At the same time,sediment has been deposited on the entrance region.Erosion and deposition had responded rapidly to the construction of the regulation engineering.There was about one year duration of lagging between erosion in the deep channel and the construction of the regulation engineering.The siltation lag of time in the groin field varied with the initial depth,but the average deposited thickness was about 0.5 m per year.Volumetric analysis demonstrates that there is a increasing trend of siltation in the North Passage after 2002,because of the difference in duration and quantity between erosion in the deep channel and deposition in the groin field.The water volume of the North Passage was reduced by ≈9%(280 million m3)between 2002 and 2006.Sediment budget reveals that the main sediment deposited in the North Passage takes its source from the river and the ocean.The decreasing water volume was attributable to shoaling in the groin field.Its triggering factors for increased sedimentation are the navigational improvements(jetties and groins)after 1998,which altered the passage boundary and destroyed the equilibrium state on the average ebb and flood sediment fluxes.The establishment of a stable estuary is attributed to a reduction in depth of the groin field.The forecast on the sediment deposition quantity and continuous infilling time in the groin system is about 325×106m3 and 6～7 years,respectively.  相似文献   

9.
This study deals with a unusual cooling event after Typhoon Mujigea passed over the northern South China Sea(SCS) in October 2015. We analyze the satellite sea surface temperature(SST) time series from October 3 to 18,2015 and find that the cooling process in the coastal ocean had two different stages. The first stage occurred immediately after typhoon passage on October 3, and reached a maximum SST drop of –2℃ on October 7 as the usual cold wake after typhoon. The second stage or the unusual extended cooling event occurred after 7d of the typhoon passage, and lasted for 5d from October 10 to 15. The maximum SST cooling was –4℃ and occurred after 12d of typhoon passage. The mechanism analysis results indicate that after landing and moving northwestward to the Yunnan-Guizhou Plateau(YGP), Typhoon Mujigea(2015) met the westerly wind front on October 5. The lowpressure and positive-vorticity disturbances to the front triggered meridional air flow and low-pressure trough,thus induced a katabatic cold jet downward from the Qinghai-Tibet Plateau(QTP) passing through the YGP to the northwestern SCS. The second cooling reached the maximum SST drop 4d later after the maximum air temperature drop of –9℃ on October 11. The simultaneous air temperature and SST observations at three coastal stations reveal that it is this katabatic cold jet intrusion to lead the unusual SST cooling event.  相似文献   

10.
Fatigue analysis of the taut-wire mooring system applied for deep waters   总被引：1，自引：0，他引：1  
Precisely predicting the fatigue life of taut-wire mooring systems has become an interesting and important problem for scientists and engineers since there are still difficulties in the inspection and maintenance of mooring lines in a rough sea environment especially in deep waters. In this paper, a comprehensive fatigue analysis is performed for a polyester taut-wire mooring system of an FPSO based on the time domain dynamic theory, rainflow cycle counting method and linear damage accumulation rule of Palmgren-Miner. Three influential factors in the fatigue analysis including the pre-tension, dynamic stiffness and T-N curve are investigated in detail. Two polyester T-N curves, one is from the DNV- OS-E301 and the other is from the API-RP-2SM, are adopted in the calculation. The fatigue analysis of the mooring system after one-line failure is also carried out. The calculation results indicate that the fatigue life is significantly affected by the T-N curve. The fatigue life decreases with increasing pre-tension, and is largely reduced if taking into account the dynamic stiffness caused by cyclic loading. The analysis also proves that one-line failure has remarkable effects on the fatigue lives of other mooring lines. The present parametric and comparative study is believed to be meaningful to further understanding of the taut-wire mooring system for deepwater applications.  相似文献   

11.
王朝晖  钟文聪  廖姿蓉 《海洋科学》2017,41(10):102-108
敌百虫是使用最为广泛的有机磷农药之一,在水产养殖中主要用于防治甲壳类寄生虫。本文研究了72 h的急性暴露以及25 d的亚慢性暴露下,敌百虫对两种赤潮微藻海洋卡盾藻和锥状斯氏藻生长的影响,以了解敌百虫对海洋微藻的毒性及海洋初级生产力的影响。在急性暴露下,高质量浓度敌百虫能明显抑制两种藻细胞的生长,而低质量浓度则对藻细胞的生长影响不明显,敌百虫对海洋卡盾藻和锥状斯氏藻生长的72 h EC50分别为32.1 mg/L和22.1 mg/L。在亚慢性暴露下,两种藻细胞对敌百虫的敏感性相近,高质量浓度组(25 mg/L)的藻细胞在暴露的第7~9天就全部死亡;1 mg/L的低质量浓度组,藻细胞的生长状况与对照组相近;5 mg/L和10 mg/L质量浓度组在暴露初期对藻细胞生长具有抑制作用,但在暴露后期则明显刺激了藻细胞的生长。本研究说明水环境背景质量浓度下的敌百虫不会抑制浮游植物的生长,但施药一段时间后,可刺激藻细胞的生长,从而增加了引发赤潮的风险。  相似文献   

12.
采用常规急性实验方法,研究了不同干露胁迫条件对脊尾白虾(Exopalaemon carinicauda)成活率的影响。结果表明,保持虾体湿润并用冰块降温的P组干露胁迫12h后成活率为75%,显著高于其它各实验组(P<0.05)。采用实时荧光定量PCR方法研究了不同干露胁迫条件对脊尾白虾血细胞和肝胰腺组织中热休克蛋白70(HSP70)和ferritin基因表达的影响。干露胁迫能诱导脊尾白虾血细胞、肝胰腺HSP70基因的表达上调,肝胰腺中的高表达时间相对血细胞中出现的较早;干露胁迫能诱导湿润低温P组脊尾白虾血细胞和肝胰腺ferritin基因的表达上调,并显著高于对照组(P<0.05),而且各组织ferritin基因表达的上调时间具有差异性,血细胞最先上调。其余实验组脊尾白虾各组织ferritin基因表达均下调,并显著低于对照组(P<0.05)。上述结果表明,在脊尾白虾受干露胁迫的耐受范围内,HSP70和ferritin基因发挥抗氧化功能。  相似文献   

13.
The role of vitellogenin in the transport of organochlorines was investigated in Atlantic croaker (Micropogonias undulatus) by exposing them through the diet to o,p′-DDT at a concentration of 10.8 μg/100 g fish/day for 14 days or Aroclor 1254 (PCB) at a concentration of 0.5 mg/100 g fish/day for 30 days during gonadal recrudescence. Tissue samples were taken from the fish at various times after initial exposure, and o,p′-DDT and PCBs were extracted in acetonitrile and analyzed by gas chromatography. Analysis of the ovarian tissue collected 2 and 3 weeks from the start of exposure revealed that the o,p′-DDT concentration increases as the gonadosomatic index (GSI) increases (r2 = 0.63), with accumulation ranging from less than 1% to as much as 8% of the total dosage. Interestingly, o,p′-DDT did not accumulate in the testes during the same exposure period. Accumulation of PCBs was found to be 40 times higher in the ovaries than in the testes. Gel filtration of plasma from exposed females showed that o,p′-DDT elutes in the low density lipoprotein and vitellogenin fractions. Control plasma incubated with o,p′-DDT at 4 °C for 16 h followed by chromatography on Sepharose 6B gave similar results with an o,p′-DDT concentration of 0.6μg/mg protein in the vitellogenin fraction. Furthermore, both o,p′-DDT and PCBs were found to bind to purified croaker vitellogenin. These results suggest that lipoproteins, including vitellogenin, are involved in the transport and accumulation of organochlorines in the ovaries of exposed fish.  相似文献   

14.
雷雯雯  徐团  王兰 《海洋与湖沼》2012,43(2):299-305
采用急性毒性实验方法,研究了不同浓度氯化镉(0、7.25、14.50、29.00、58.00和116.00mg/L)处理不同时间(1d、3d、5d和7d)对长江华溪蟹心肌细胞凋亡的影响。结果表明,低浓度组及染毒时间较短时镉对心肌的影响不明显,但随着染毒浓度的增加和时间的延长,心肌出现空泡变性、玻璃样变性、炎细胞浸润等病理现象,在染毒7d虽然观察到疑似的凋亡细胞,但凋亡率较低;荧光显微镜未观察到心肌细胞典型的凋亡细胞核形态学变化;琼脂糖凝胶电泳图谱未出现凋亡细胞所特有的梯状条带;流式细胞术检测结果显示镉处理组细胞凋亡率增加,但与对照组相比,无统计学意义(P>0.05);Caspase-3活性也没有显著性变化(P>0.05)。因此,在本实验所选取的浓度和时间范围内,镉未诱导长江华溪蟹心肌细胞发生细胞凋亡,这与本课题组前期研究中观察到的肝胰腺、精巢组织在染毒2d、7d发生细胞凋亡的情况明显不同,这可能与心脏组织的特殊性、不同组织对镉的积累量不同有关。  相似文献   

15.
研究分析了嗜水气单胞菌(Aeromonas hydrophila)感染斑马鱼后肠道生理健康和肠道微生物的变化。以斑马鱼为研究对象,刮伤皮下真皮,使用105 CFU/mL浓度的嗜水气单胞菌暴露6 h后转入清水,分别在暴露前、暴露后6 h、12 h、24 h取样。使用鱼特异性酶联免疫吸附试验(ELISA)试剂盒,检测肠道中紧密连接蛋白ZO-2 (TJP2)含量和乙氧基异戊二烯-O-脱乙基酶(EROD)酶活性,结果表明,嗜水气单胞菌暴露引起了斑马鱼肠道生理损伤,表现为肠道TJP2含量、EROD酶活性在暴露后显著下调。采用16S rRNA高通量测序检测肠道微生物及其菌群结构变化,嗜水气单胞菌暴露斑马鱼后致病菌不动杆菌属(Acinetobacter)明显增加,OTUs数量明显下降,Alpha多样性降低,结果说明嗜水气单胞菌引起了斑马鱼肠道菌群失调。肠道中微生物的多样性与改善肠道上皮和黏膜屏障功能紧密相关,该研究对从肠道健康的角度评价嗜水气单胞菌毒性,探索嗜水气单胞菌的致病机制具有重要意义。  相似文献   

16.
海上风电场建设期风机打桩会产生高强度的水下噪声,研究水下冲击打桩噪声的监测方法、特性分析及对海洋生物的影响是非常重要的。采用自容式水下声音记录仪,多点同步测量了福建省兴化湾海上风电场二期工程建设期单次完整的水下冲击打桩噪声,从时频域特性进行了分析,并利用最小二乘法拟合得到了打桩声源级和声暴露级。结果表明：水下冲击打桩噪声是典型的低频、高强度的脉冲信号,单个脉冲持续时间约90~100 ms,峰值声源级约209.4±2 dB,声暴露级约197.7±2 dB;主要能量分布在50 Hz~1 kHz频段,750 m测量点的该频段声压级相比海洋环境背景噪声,提高了约40~50 dB。水下冲击打桩噪声频域能量分布与大黄鱼的听觉敏感频段相重叠,对大黄鱼影响程度和范围较大,实际工程应用中宜采用声暴露级作为评价指标。  相似文献   

17.
本研究采用RT-PCR和RACE技术首次获得了栉孔扇贝(Chlamys farreri)BI-1基因(Cf BI-1)c DNA全长序列,长度957bp,5′和3′非编码区长度分别为48bp和195bp,开放阅读框为714bp,预测编码一个含有237个氨基酸的蛋白质,分子量为27k Da;结构预测显示,Cf BI-1蛋白包含6个跨膜结构域。同源和分子进化聚类分析显示,Cf BI-1蛋白序列与其他一些物种中的BI-1蛋白序列相似性很高,表明BI-1具有很高的保守性。通过荧光定量PCR的方法检测了Cf BI-1 m RNA在栉孔扇贝正常组织中和在干露、脂多糖以及扇贝急性病毒性坏死症病毒刺激之后的表达水平的变化。结果表明,Cf BI-1在栉孔扇贝各组织中广泛分布,其中闭壳肌中的表达量最高,血淋巴中的表达量最低。在干露和病毒刺激以后,Cf BI-1基因表达水平较对照组都有显著上调(P0.05),表明Cf BI-1基因可能参与了干露刺激和急性病毒性坏死症病毒感染后的细胞应激响应及其诱导的细胞凋亡过程。综合上述分析,我们认为Cf BI-1基因在栉孔扇贝细胞凋亡调控过程中可能起到重要作用,可为栉孔扇贝凋亡相关基础研究提供参考。  相似文献   

18.
孙静  黄勇 《海洋科学》2021,45(1):14-21
在对东海的自由生活海洋线虫进行分类和多样性研究中,发现2个我国新纪录种并进行了描述。深海螺旋球咽线虫Spirobolbolaimus bathyalis Soetaert&Vincx,1988的主要鉴别特征为:体表具显著的环纹,头感觉器呈乳突状,化感器螺旋形,口腔中部具有一个背齿以及一对亚腹齿,咽前后各有一个咽球;具有两条弧形的交接刺,引带呈板状,无肛前辅器,具两个反向排列的直伸精巢。伸长丝瘤线虫Filoncholaimus prolatus Hopper,1967的主要鉴别特征为:体表光滑,内唇感觉器乳突状,十根头刚毛,口腔具一背齿及两个等大的亚腹齿,尾锥状,渐变为长丝状,锥状部分具尾刚毛;交接刺呈弧形,引带简单,板状,无引带突,具两个乳突状的肛前辅器和两个反向排列的直伸精巢。  相似文献   

19.
In the Marine Department archives, early records (1930–41) of marked parr of quinnat salmon Oncorhynchus tshawytscha (Walbaum) show that some held in freshwater hatchery ponds in south Canterbury survived development of testes for two consecutive years, and that one fish developed testes for three consecutive years and gave indications that it might survive into the fourth. It is generally believed that all wild adults of this species die after one spawning.  相似文献   

20.
为从行为学角度解释中国蛤蜊(Mactra chinensis Philippi)的跑滩现象, 研究了规格、温度对其跳跃行为以及底质、流速和周期性干露对其潜沙行为的影响。结果表明, 中国蛤蜊运动能力与其规格和水温有关, 3 mm稚贝不具备跳跃能力, 5 mm以上具备跳跃能力; 跳跃频率和高度随水温的升高呈上升趋势。中国蛤蜊稚贝潜沙比例均随时间推移逐渐上升; 各时间节点中国蛤蜊稚贝在细沙底质的潜沙比例最高, 中沙底质次之, 粗沙底质最低。施加微弱水流后, 中国蛤蜊稚贝潜沙速度和比例显著增加; 流速增大到一定程度后部分稚贝被水流冲走, 潜沙比例随之下降。周期性干露会导致中国蛤蜊稚贝从底质中爬出, 干露时间越长, 爬出比例越高。干露后的稚贝重新放置于海水中, 部分稚贝会在水面漂浮一段时间后再下落至水底, 漂浮比例随干露时间的增加而增加。本研究从行为学角度初步查明了中国蛤蜊跑滩现象, 为解决中国蛤蜊防跑滩问题提供了思路。  相似文献   

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