栉孔扇贝鳃、唇瓣和口唇一氧化氮合酶活性     

王宜艳  孙虎山  王晓安 《海洋湖沼通报》2007,(3):63-68

采用组织化学、免疫组织化学和分光光度技术对栉孔扇贝(Chlamys farreri)鳃、唇瓣和口唇内的一氧化氮合酶(EC EC1.14.13.39;NOS)进行了研究。组织化学显示,鳃轴结缔组织内血细胞、血管内皮细胞、神经细胞、神经纤维呈NOS阳性;鳃丝的部分上皮细胞及血细胞呈NOS强阳性;唇瓣内部分上皮细胞、血细胞、神经细胞和神经纤维均呈NOS阳性;口唇有大量的神经纤维呈极强的NOS阳性。免疫组化显示,鳃和唇瓣血细胞、神经细胞、神经纤维和部分上皮细胞呈iNOS阳性。口唇内血细胞、神经细胞、神经纤维和部分上皮细胞呈nNOS和eNOS阳性,而呈iNOS强阳性。生化测定表明,tNOS活力和NO含量均为鳃轴中最高,鳃丝中次之,唇瓣中较低,口唇中最低,鳃丝内的NOS以cNOS为主;鳃轴和口唇内的cNOS活力和iNOS活力相近;唇瓣内的NOS则以iNOS为主。  相似文献   

沿海挡潮闸闸下淤积分析与疏浚技术     

朱国贤  项明 《海洋工程》2005,23(3):115-118

近年来随着流域水资源利用率的提高,下泄流量逐年减少,粉沙淤泥质海岸带挡潮闸闸下港道淤积加重,且日趋板结,仅靠水力冲淤已无法满足防洪排水的要求,机械疏浚愈来愈重要。通过对挡潮闸闸下淤积特性及发展趋势、常用防淤减淤措施、河床疏浚标准、疏浚技术及时机的分析,论述了只有进行基础试验,找出淤积规律,选择最佳时机,控制闸门运行,充分利用水力冲淤,同时加强测量观测,确定合理施工标准,采用科学疏浚方法,才能使港道淤积危害降低到最小。  相似文献   

The impacts of scallop dredging on sponge assemblages in the Gulf of Kalloni (Aegean Sea, northeastern Mediterranean)     

Kefalas  E; Castritsi-Catharios  J; Miliou  H 《ICES Journal of Marine Science》2003,60(2):402-410

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疏浚淤泥的土工材料化处理技术的试验与探讨   总被引：22，自引：5，他引：17  

姬凤玲  朱伟  张春雷 《岩土力学》2004,25(12):1999-2002

疏浚淤泥的弃埋会产生环境问题,如何进行处理是国内外十分关注的问题。采用固化及轻量化处理技术开发再生土工材料,具有广阔的应用前景。根据室内试验,研究了不同配比的淤泥固化土和轻量化土的无侧限抗压强度和密度,并分析了固化和轻量化的强度形成机理。疏浚淤泥土工材料化处理在技术上是可行的,且具有废物利用和保护环境的优点,可带来良好的环境效益和社会效益。  相似文献   

湖泊底泥疏浚环境效应:Ⅲ.对沉积物反硝化作用的影响   总被引：8，自引：1，他引：7  

钟继承  刘国锋  范成新  白秀玲  李宝  张路  丁士明 《湖泊科学》2009,21(4):465-473

通过为期一年的疏浚模拟试验,在试验室培养疏浚与对照柱样,研究了底泥疏浚对沉积物反硝化过程的影响.沉积物反硝化速率的测定采用经典的乙炔抑制法.研究结果表明,在一年的试验周期内,疏浚和对照柱沉积物的反硝化速率分别为6.9-26.9nmol/(g·h)和21.6-102.7nmol/(g·h),除2006年的2月外的其他月份,疏浚沉积物的反硝化速率显著(P<0.05)低于未疏浚对照沉积物,同时还研究了环境因子对沉积物反硝化速率的影响,结果表明,疏浚和对照沉积物的反硝化速率都受温度的控制.硝态氟浓度是疏浚和对照沉积物反硝化速率的主要限制因子,有机碳对疏浚沉积物的反硝化速率有影响,但对未疏浚对照沉积物的反硝化速率没有影响.疏浚后短期内沉积物反硝化速率低于未疏浚对照沉积物,可看作是底泥疏浚在富营养华水体脱氮方面的一个负效应.  相似文献   

人类活动对长江河口过程的影响   总被引：7，自引：0，他引：7  

沈焕庭  李九发  肖成猷 《气候与环境研究》1997,2(1):48-54

随着经济高速发展,人类活动对长江河口过程的影响愈益显著。本文对围海造地、排污工程、取水工程、航道增深工程、南水北调和三峡工程等几项规模较大的已建和拟建工程及其对长江河口过程的影响做了初步论述,建议继续重视和加强这方面的研究,开发要适度,人工控制要遵循自然演变基本规律,以利于该地区经济的持续发展  相似文献   

Numerical modeling of sedimentation control scenarios in the approach channel of the Nakdong River Estuary Barrage,South Korea     

《国际泥沙研究》2016,(3):257-263

The effects of sedimentation reduction at the Nakdong River Estuary Barrage (NREB) in Korea were quantitatively analyzed with respect to different sediment control methods using the calibrated and validated two-dimensional model. The countermeasures of sediment dredging, sediment flushing, channel geometry change, and a combination of flushing and channel geometry change were examined for the approach channel of the NREB. The flood event and channel geometries of the 3.8 km section upstream of the NREB surveyed before and after dredging in 2007 were used for modeling conditions. As a result, the half of sediments dredged in 2007 could be eliminated naturally by floods without dredging. The numerical simulation of sediment flushing indicated that the deposition height decreased in the entire simulation section with the minimum and maximum reductions from 0.3 m to 1.3 m in deposition height. The channel contraction method produced quantitatively the largest amount of sedimentation reduction and sediment flushing and dredging followed. Sedimentation reduction by a combination of flushing and channel contraction was up 10%compared to the individual method of channel contraction.  相似文献   

Channel and vegetation recovery from dredging of a large river in the Gulf coastal plain,USA     

Joann Mossa  Yin-Hsuen Chen  G. Mathias Kondolf  Scott Porter Walls 《地球表面变化过程与地形》2020,45(9):1926-1944

Anthropogenic impacts in large rivers are widely studied, but studies of recovery once a disturbance has stopped are uncommon. This study examines the biogeomorphic recovery of a 40-km river corridor on the mid-Apalachicola River, Florida following the cessation of dredging, disposal, and snag removal in 2002. This failed navigation project resulted in vegetation losses (~166 ha between 1941 and 2004), river widening, and increased point bar areas. We used paired sets of imagery for a 10-year period during the recovery process at two different flow levels to assess sand bar change, land cover change, and their spatial variations. Most large sand bars decreased significantly in area due to growth of pioneer species, typically from the bankside of the bar. Mean bar area shrank 0.17 and 0.20 ha for the 30th and 1st percentile flows, respectively. For the entire study area, both water-level comparisons showed gains in vegetation (23.36 and 15.83 ha), compensated by losses in the extent of water (16.83 and 8.55 ha) and sand bar losses (6.53 and 7.28 ha). Overall, these gains during the 10-year passive recovery period are equivalent to ~15% of the vegetation losses that resulted from the navigational dredging. As found in other studies, most of the pioneer vegetation grew approximately 2 m relative elevation above the low-water surface. The initial length of the tree line and the area of herbaceous growth both had a significant and positive relationship with the area of new vegetation growth over the study interval. As parts of the river are healing, reduced channel capacity from narrowing and tree growth will benefit the floodplain. As elsewhere, understanding of a river's biogeomorphology, hydrology, and disturbance history can help in selecting appropriate recovery metrics to further advance the understanding and management of disturbed floodplains. © 2020 John Wiley & Sons, Ltd.  相似文献   

气泡羽流的研究进展和应用     

潘青青  伍骏 《海洋预报》2019,36(2):97-104

从试验、积分羽流模型、CFD模型方面综述了气泡羽流的研究现状。在此基础上,介绍了一些应用领域的研究进展,包括海上天然气泄露、海上溢油的围控、水处理和污水处理以及疏浚工程。  相似文献   

胶州湾扇贝养殖对海域环境影响的初步研究   总被引：5，自引：0，他引：5  

杨卫华  高会旺  刘红英  高永刚  傅明珠 《海洋湖沼通报》2007,(2):86-93

在2004年11月17日对胶州湾西部扇贝养殖区及周围海区进行的综合海洋环境调查的基础上,分析了胶州湾秋季扇贝养殖区与非养殖区的海洋环境状况,初步探讨了扇贝养殖在收获期对养殖区环境的影响。胶州湾养殖区表层水中COD和无机营养盐含量,除了NO2 -N的变化不明显外,均高于非养殖区的值。养殖区底层水中溶解氧含量和表层沉积物中硫化物的含量均明显超标。因此,肢州湾的扇贝养殖在收获期对环境的影响也是综合性的,且养殖海域的环境同时受陆源、水动力状况及养殖活动的综合影响。  相似文献