首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 781 毫秒
1.
本文研究了10 mg/L的Ni~(2+)和5 mg/L的金霉素(CTC)对序批式反应器(SBR)性能、微生物酶活性和微生物群落的影响。结果表明,COD去除率在反应器整个运行过程中始终保持在90%以上。10 mg/L Ni~(2+)单独存在及其与5 mg/L CTC共存均能导致氮去除率的下降,且在二者共存时下降程度最大,表明Ni~(2+)和CTC共存对氮的去除呈现协同抑制作用。随着进水中Ni~(2+)和CTC的加入,活性污泥的耗氧速率、硝化和反硝化速率均有所降低。脱氢酶活性以及与脱氮相关的微生物酶活性的变化趋势与耗氧速率和相应的硝化反硝化速率的变化趋势保持一致,均出现了一定程度的降低。Ni~(2+)和CTC共存对硝化反硝化活性呈现协同抑制作用,协同抑制作用主要依赖于Ni~(2+)的含量。Ni~(2+)和CTC共存对活性污泥中活性氧(ROS)的产生和乳酸脱氢酶(LDH)的释放呈现协同促进作用,可以诱导活性污泥细胞内氧化应激以及细胞损伤。长期暴露条件下添加10 mg/L Ni~(2+)和5 mg/L CTC会降低微生物群落的丰富度和多样性。Ni~(2+)和CTC的存在显著抑制了活性污泥中硝化菌(Nitrosomonas、Nitrospira)和反硝化菌(Thauera、Longilinea、Denitratisoma和Anaerolinea)的相对丰度,从而抑制了SBR的脱氮性能。  相似文献   

2.
本文研究了长期暴露条件下镀镍多壁碳纳米管(MWCNTs-Ni)对序批式反应器(SBR)性能、微生物酶活性和微生物群落的影响。研究结果表明,10 mg/L MWCNTs-Ni的长期暴露未对SBR去除有机物产生影响,而NH_4~+-N的去除率由(99.10±0.60)%明显降至(39.04±1.61)%。与进水中未加入MWCNTs-Ni时的第32天相比,活性污泥比耗氧速率(SOUR)和脱氢酶(DHA)活性在第148天时分别降低了17.43%和24.32%;而脱氮速率和与脱氮相关的微生物酶活性均降低了60%以上,从而导致SBR对氮的去除效果明显降低。MWCNTs-Ni的长期暴露导致活性污泥活性氧(ROS)产生量和乳酸脱氢酶(LDH)释放量在第148天时分别增加了67.23%和65.33%,表明MWCNTs-Ni的长期暴露能够诱导活性污泥中微生物产生氧化应激和细胞膜损伤。高通量测序结果表明,长期暴露于10 mg/L的MWCNTs-Ni条件下,活性污泥中与硝化过程相关菌属(Nitrosomonas、Nitrosospir、Nitrospira)和与反硝化过程相关菌属(Dokdonella、Dechloromonas、Steroidobacter、Devosia、Thermomonas)的相对丰度明显降低,进而影响到SBR对氮的去除。该研究结果可为评价MWCNTsNi对污水生物处理系统的潜在影响提供一定的理论基础和技术依据。  相似文献   

3.
本文考察了二价钴离子(Co(II))浓度变化对序批式反应器(SBR)性能、脱氮速率、微生物酶活性和微生物群落的影响。结果表明,进水中Co(II)浓度在0~10 mg/L时,COD和NH~+_4-N去除率分别为(92.21±1.31)%和(98.40±0.66)%。在进水Co(II)浓度为20 mg/L时,COD和NH~+_4-N去除率分别降至(81.78±0.52)%和(80.30±1.08)%。与进水未添加Co(II)时相比,活性污泥比耗氧速率、脱氮速率、脱氢酶活性和与脱氮相关的微生物酶活性在进水Co(II)浓度小于5 mg/L时略微升高,而在进水Co(II)浓度为10和20 mg/L时则明显降低。活性污泥活性氧产生量和乳酸脱氢酶释放量随进水Co(II)浓度升高而逐渐增加,表明Co(II)的存在能造成细胞氧化应激和细胞膜损伤。随着进水Co(II)浓度从0 mg/L升至20 mg/L,活性污泥微生物群落丰富度和多样性逐渐降低,且活性污泥中硝化菌属(Nitrosomonas、Nitrospira)和反硝化菌属(Luteimonas、Flavobacterium、Comamonas、Thauera和Zoogloea)的相对丰度发生改变,从而影响SBR脱氮性能。  相似文献   

4.
本文研究碳氮(C/N)比变化对移动床生物膜反应器(MBBR)处理海水养殖废水性能的影响。结果表明,当C/N比从7∶1降至3∶1,出水COD浓度无明显变化,平均去除率保持在90%以上。C/N比的变化对脱氮过程有较大影响,当C/N比从7∶1降低至3∶1,NH+4-N去除率由89.51%±1.24%增至92.70%±1.08%,NO-2-N浓度由(4.84±0.50)mg/L降至0 mg/L,NO-3-N浓度由(0.47±0.29)mg/L升至(8.12±0.25)mg/L。C/N比的降低提高了比氨氧化速率、比亚硝酸盐氧化速率和与硝化相关的微生物酶活性,但降低了比耗氧速率、比硝酸盐还原速率、比亚硝酸盐还原速率、脱氢酶活性和与反硝化相关的微生物酶活性。松散型胞外聚合物和紧密型胞外聚合物的多糖含量随C/N比的降低而降低,说明在低COD条件下,多糖能够被微生物利用。微生物群落的丰富度和多样性随C/N比的降低而降低,硝化菌属(Nitrosomonas和Nitrospira)和反硝化菌属(Azoarcus、Comamonas、Hyphomicrobium、Paracoccus、Thauera、Devosia、Pseudomonas和Rhodanobacter)的相对丰度发生改变,从而影响MBBR脱氮性能。  相似文献   

5.
采用能耐受3%盐度的活性污泥处理高盐度废水,探究了盐度升至4%~7%对污染物去除的影响,考察了微生物活性和群落结构随盐度升高的变化。结果表明,盐度提升到4%、5%和6%对COD、NH~+_4-N和总无机氮(TIN)去除几乎没有影响,而7%盐度时三者的去除率均明显下降;盐度提高到4%对污泥的氨氧化活性和亚硝酸盐氧化活性有刺激作用,使两者提高,而盐度提高到5%、6%和7%时氨氧化活性受到明显抑制,亚硝酸盐氧化活性在6%和7%盐度条件下明显降低;盐度提升使硝酸盐和亚硝酸盐还原活性均受到明显抑制;耗氧速率测试结果表明,盐度提升对自养硝化菌的负面影响较异养好氧菌更大。微生物群落结构随盐度升高发生了明显变化,微生物群落丰富度和多样性均在6%盐度时最大,3%盐度时Roseovarius为优势菌属,而盐度提高至4%~7%时Azoarcus成为优势菌属。氨氧化菌(AOB)只在3%、4%和6%盐度下被检出,亚硝酸盐氧化菌(NOB)在所有盐度下均未检出,短程硝化反硝化(PND)为主要脱氮途径;自养反硝化菌、好氧反硝化菌和厌氧氨氧化菌的存在说明脱氮途径不局限于传统的自养硝化-异养反硝化。盐度驯化提高了活性污泥的抗盐能力,使生物法处理超高盐废水成为可能。  相似文献   

6.
本文以PP为唯一碳源对青岛近海海水和沉积物样品中的微生物进行实验室富集培养,对不同富集时间的富集水样及微塑料附着细菌的群落结构进行分析并对富集40 d的PP附着细菌进行分离、鉴定及PP降解活性检测。通过16S rRNA基因高通量测序及分析,发现PP附着细菌出现明显的群落演替,群落多样性随富集时间的延长而增大。PP附着细菌在富集过程中,γ-变形菌纲假单胞菌属(Pseudomonas)和不动杆菌属(Acinetobacter)细菌占绝对优势,其次为α-变形菌纲扎瓦尔金氏菌属(Zavarzinia)及拟杆菌纲(Bacteroidia)细菌。富集培养获得的铜绿假单胞菌LXI681(Pseudomonas aeruginosa)和反硝化无色杆菌LXI668(Achromobacter denitrificans)对PP具有降解活性。本研究为缓解PP微塑料污染提供了潜在的微生物菌种资源。  相似文献   

7.
通过高通量测序考察了不同月份青岛海泊河污水处理厂缺氧池中微生物群落的动态变化。研究结果表明,在8和10月缺氧池中微生物群落丰度较高,1月缺氧池污泥中微生物群落丰度较小。缺氧池微生物群落多样性在12月较高,在6月微生物群落多样性较小。不同月份缺氧池中共有分类操作单元(OTU)中占优势地位的门包括Proteobacteria(42.3%)、Bacteroidetes(21.0%)、Chloroflexi(6.5%)、Firmicutes(6.3%)、Actinobacteria(4.0%)和Planctomycetes(3.8%),大部分微生物一直存在于缺氧池中。污泥样品中微生物群落的主成分分析和主坐标分析表明,8和10月缺氧池中微生物群落比较相似,但与1月污泥样品中的微生物群落之间存在着明显的差异。进水水质和环境温度的变化导致在门、纲和属水平上缺氧池内微生物的种类和相对丰度在不同月份呈现明显的变化。  相似文献   

8.
冰川土壤中的微生物是冰冻圈生态系统中的重要组成部分。南极纳尔逊冰川四周环海,临近海洋的物质输送和其他因素扰动改变了近岸土壤中部分理化因子,从而对土壤中的微生物群落产生影响。本研究采集了南极纳尔逊冰川不同近海距离处的土壤样品,并对其进行了细菌和古菌V4区扩增子测序以及宏基因组测序,探讨了不同近海距离的冰川土壤中的微生物群落结构和代谢潜能。物种多样性结果显示,不同位点的土壤微生物群落组成有所差异,但变形菌门、放线菌门、拟杆菌门等在冰川土壤样品中普遍存在且相对丰度较高。宏基因组分析结果显示,不同近海距离的冰川土壤微生物群落的功能基因分布不同,且能量代谢和跨膜运输等代谢途径的基因的丰度随着采样位点远离海洋而降低。冰川土壤中碳、氮、硫代谢分别以还原性柠檬酸循环、反硝化、同化硫酸盐还原途径为主,其中反硝化途径基因在所有样品中丰度较高。通过分箱组装获得了含有反硝化功能基因的基因组bin_71,并重构了其核心的代谢通路。本研究初步揭示了南极纳尔逊冰川土壤中微生物的群落结构及代谢潜能,为后续南极冰川土壤新物种的发现、功能基因的挖掘、以及探究全球气候变暖下海洋对沿海生态系统的影响提供了基础数据。  相似文献   

9.
本文采用Biolog-ECO微平板技术,分析了不同水力停留时间(hydraulic retention time,HRT)5、6、7h和进水硝酸盐(NO3ˉ-N)浓度50、100、150mg/L时,好氧反硝化反应器微生物群落结构和代谢功能特征。研究结果表明:在同一进水硝酸盐浓度下,水力停留时间越长,微生物代谢活性越强(P0.05);在同一水力停留时间下,不同进水NO3ˉ-N浓度下微生物平均吸光值(用平均颜色变化率AWCD指示)的大小顺序为50150100mg/L(P0.05),说明进水NO3ˉ-N浓度对微生物代谢活性有一定影响。反应器内微生物对不同碳源的代谢利用由强到弱的顺序是:多聚物氨基类碳水化合物羧酸类胺类酚酸类。不同处理组的Shannon-Wiener指数、Simpson指数、Pielou指数、Mc Intosh指数相互之间差异显著(P0.05),其中HRT为7h、NO3ˉ-N为150mg/L以上处理组微生物多样性指数最高。本实验采用Biolog-ECO板来分析在好氧反硝化反应器中微生物的群落代谢特征,研究结果可为通过碳源调节生物滤池水处理效果提供科学依据,以此提高水处理效率。  相似文献   

10.
本文研究了铁酸锌纳米颗粒(ZnFe_2O_4 NPs)浓度变化对序批式反应器(SBR)性能、微生物酶活性和微生物群落的影响。结果表明:0~50mg/L的ZnFe_2O_4 NPs对COD和NH_4~+-N的去除未产生影响,出水NO_2~--N浓度接近于0mg/L,而出水NO_3~--N浓度在3.89~5.63mg/L之间变化。随着进水,ZnFe_2O_4 NPs浓度从0mg/L增加到50mg/L,活性污泥的比耗氧速率(SOUR)、比氨氧化速率(SAOR)、比亚硝酸盐还原速率(SNIRR)、脱氢酶(DHA)、氨单加氧酶(AMO)和亚硝酸盐还原酶(NIR)的活性逐渐降低。与进水ZnFe_2O_4 NPs浓度为0mg/L时相比,活性氧(ROS)产生量和乳酸脱氢酶(LDH)释放量的变化表明,ZnFe_2O_4 NPs对活性污泥中微生物有一定毒性效应。ZnFe_2O_4 NPs的浓度变化导致微生物群落种类和相对丰度在门和属水平上发生变化。该研究结果为评价ZnFe_2O_4 NPs对污水生物处理系统的潜在影响提供可靠的理论基础和技术依据。  相似文献   

11.
根据1999年10月至2000年9月对广东柘林湾每月一次的监测结果,分析了柘林湾海域氮磷的分布特征和来源,并用营养状态质量指数(NQI)法评价了增养殖区的营养水平。结果表明:柘林湾海域氮磷的分布特征表现为西、北部海区大于东、南部海区,近岸高于离岸的基本格局,其主要来源为陆源排污和海水养殖自身污染。目前,柘林湾整个海区处于严重富营养化水平。  相似文献   

12.
海洋微型鞭毛虫是海洋微型真核浮游生物中非常重要的一大类群,在构成和维持海洋生态系统的结构和功能中扮演着重要角色。微生物群落通常由少数优势种和大量稀有种组成,这种分布模式在海洋微型鞭毛虫群落中也极为常见,并且二者的内在特征可能对群落生物地理分布格局以及生态系统功能产生不同影响。然而在多数研究中并未将两种不同亚群落进行区分,对二者的分布特征、对环境和空间因子的响应以及在总体群落中的生态地位等的认识十分有限。本研究利用高通量测序技术,调查了中国近海亚热带 热带3个自然海区微型鞭毛虫群落中优势种和稀有种的分布特征,并探讨了环境因子和空间因子与不同亚群落之间的关系,利用中性模型揭示了中性过程在群落构建中的作用,最后通过共现网络分析解析了两种不同亚群落在总体群落中的生态地位。结果表明:3个海区微型鞭毛虫群落中的优势类群和稀有类群在多样性和物种组成上具有不同的特征,表现出一定的生物地理分布格局;这与它们受到不同程度环境因子和空间因子的驱动作用有关;中性模型的结果体现了随机过程在两种亚群落中的重要作用;最后,共现网络关系反映出不同丰富程度的生态类群具有重叠但又相异的生态位,从而在同一环境中形成物种的共存,维持了群落结构的稳定,而稀有类群以较高的连接度和更高比例的关键种数目,在网络关系中起到重要的连接作用。本研究初步揭示了中国近海微型鞭毛虫优势种和稀有种的分布特征和建群机制,为深入认识海洋微型鞭毛虫的群落结构、分布格局以及影响其群落构建的生态过程提供理论依据。  相似文献   

13.
Abstract. A new concept (‘enzyme sharing’) concerning the interaction of marine nematodes and microbes in the degradation of sedimentary detritus is presented. Elements of this concept are (1) the notorious tendency of many aquatic nematodes to agglutinate detrital particles by mucus secretions, (2) new observations on the stimulation of microbial growth by nematodes in agar plates, and (3) literature data on limited endogenous proteolytic capacities of aquatic nematodes.
Observations on nematode‐microbe associations in agar plates prompted the conceptual synthesis. In agar medium without the addition of any nutrients a spectacular growth of bacteria was visible on the sinusoidal crawling trails of nematodes only 2 – 3 days after introduction of the worms (species of Adoncholaimus, Anoplostoma and Sabatieria). Juveniles of Anoplostoma that hatched in the agar cultures left their minute trails in the medium and these were rapidly occupied by bacteria. The nematodes repeatedly visited their bacterial trails, which persisted as a peculiar biotic structure for more than one year and survived the nematodes.
In sterile agar preparations containing the fluorogenic methylumbelliferyl‐β‐glucoside in the presence of the nematode Adoncholaimus, an enhanced fluorescence of the medium was visible, indicating β‐glucosidase activity. We therefore assume that oncholaimid nematodes discharge enzymes that alone, or in concert with microbial activities, contribute to the hydrolytic cleavage of refractory polysaccharides containing β‐glucosidic bonds such as agar components and cellulose. The sugars thus produced may then be taken up by the nematodes and concomitantly support the conspicuous growth of microbes. Since we did not observe any feeding of the nematodes on the associated microbes in agar plates, we question the nutritive potential of intact microbial cells for a number of nematodes abounding in detrital habitats, and call attention to the significance of ambient dissolved or adsorbed organic monomeric nutrients.
Consequently, we perceive the puzzling perpetual accretion of detrital organic particles to sediment agglutinations by nematodes as an adaptation for operating an ‘enzymatic reactor’ for the production of dissolved nutrients. We hypothesise a relationship of mutual commensalism of nematodes and heterotrophic microbes in detrital habitats and propose the term ‘enzyme sharing’ for this relationship. Both parties invest in a common enzyme pool that decomposes organic detritus for their nutrition. We present here evidence that nematodes contribute β‐glucosidase, which is involved in the cellulase system. Data from the literature suggest that microbial enzymatic processing of detrital proteins yields amino acids available to nematodes, which apparently have no efficient proteolytic enzyme system in their intestines.  相似文献   

14.
We examined bacterioplankton biomass and heterotrophic production (BHP) during summer stratification in the northwestern Mediterranean in four successive stratification seasons (June–July of 1993–1996). Values of phytoplankton biomass and primary production were determined simultaneously so that the data sets for autotrophic and heterotrophic microbial plankton could be compared. Three standard stations were set along a transect from Barcelona to the channel between Mallorca and Menorca, representing coastally influenced shelf waters, frontal waters over the slope front, and open sea waters. Conversion factors from 3H-leucine incorporation to BHP were empirically determined and varied between 0.29 and 3.25 kg C mol-1. Bacterial biomass values were among the lowest found in any marine environment. BHP values (between 0.02 and 2.5 μg C L-1 d-1) were larger than those of low nutrient low chlorophyll areas such as the Sargasso Sea and lower than those from high nutrient low chlorophyll areas such as the equatorial Pacific. Growth rates of bacterioplankton were highest at the slope front (0.20 d-1) and lowest at the open sea station (0.04 d-1). Phytoplankton growth rates were similar at the three stations (∼0.50 d-1). Integrated values of bacterioplankton biomass, BHP and bacterial growth rates did not show significant differences among years, but differences between the three stations were clearly significant. Phytoplankton biomass, primary production, and phytoplankton growth rates did not show significant differences either with year or with station. As a consequence the bacterioplankton to phytoplankton biomass (BB/BPHY) and production (BHP/PP) ratios varied from the coastal to the open sea stations. The BB/BPHY ratio was 0.98 at the coast and ∼0.70 at the other two stations. These ratios are similar to those found in other oligotrophic marine environments. The BHP/PP ratio was 0.83 at the coast, 0.36 at the slope and 0.09 at the open sea station. The last value is also similar to values found in other oligotrophic marine environments. Vertical distribution of these ratios was also examined.The comparison of microbial parameters at the three stations indicates a different kind of relationship between bacterioplankton and phytoplankton in oligotrophic open sea waters and in coastal, nutrient-richer waters. According to such parameters and to the values of the BB/BPHY and BHP/PP ratios, open waters in the northwestern Mediterranean (despite their relatively short distance from the shore) were intermediate between the extremely oligotrophic waters of the eastern Mediterranean or the Sargasso Sea and the more productive waters of the equatorial Pacific.  相似文献   

15.
There is a well-defined succession of micro-organisms which colonize powdered leaf debris from Spartina alterniflora and Juncus roemerianus, and aged natural detrital material when these were incubated in estuarine water at temperatures near to those recorded in the habitat at the time of collection. The natural assemblage of free-living bacteria in estuarine water rapidly enters logarithmic growth, subsequently declining with the increase in numbers of bactivorous microflagellates. These are then replaced by a mixed population of ciliates, choanoflagellates, amoeboid forms and attached bacteria which form part of a complex microbial community associated with particulate debris. The rate of increase of bacterial cells (μ), in both spring and summer experiments ranged from 0·010–0·108 h?1 whilst estimates of bacterial carbon production ranged from 1·5 to 10·1 μg C 1?1 h?1, values which conform well with estimates obtained from natural assemblages of marine bacteria in coastal and estuarine waters elsewhere. Although both the ease of degradation of the detrital substrate and incubation temperature are of importance, enrichment of both powdered Spartina leaf debris and aged natural detritus with inorganic nutrients evidently enhances bacterial production under experimental conditions. In addition, the amount of carbon utilized to sustain bacterial carbon production shows a significant reduction following enrichment with NH4, NO3 or combinations of NO3 + PO4. The bacterial carbon conversion efficiency (μg C incorporated into bacterial production per μg C consumed) × 100, based on powdered Spartina leaves, and aged natural detritus, is thus increased from 9–14%, to as much as 38% in nutrient enriched media. Since NH4, NO3 and PO4 values are generally low in the water column, it seems likely that bacteria achieve a carbon conversion of only 9–14% on natural suspended detrital material, with the possibility of an enhanced conversion of up to 38% occurring at the sediment-water interface where ammonia regeration occurs. This suggests that suspended bacteria which characterize estuarine waters of salt marsh areas may be responsible for the oxidation of 86–91% of the carbon which enters water column microheterotroph food chains, and are probably implicated in the large CO2 fluxes recently recorded from coastal wetland habitats.  相似文献   

16.
通过1995年4月至1996年1月间对大鹏湾南澳水域网箱养殖区、非养殖区、某养殖场进出水口处海水营养盐(NH4-N,NO3-N,NO2-N,PO4-P)的含量检测,分析了其含量水平、平面与垂直含量分布、含量季节变化以及海水氮磷比值(N/P)和海水营养质量状况。为了解网箱养殖海域自身污染与赤潮发生的关系提供了基础资料。  相似文献   

17.
This paper synthesizes recent findings regarding microbial distributions and processes in the bathypelagic ocean (depth >1000 m). Abundance, production and respiration of prokaryotes reflect supplies of particulate and dissolved organic matter to the bathypelagic zone. Better resolution of carbon fluxes mediated by deep microbes requires further testing on the validity of conversion factors. Archaea, especially marine Crenarchaeota Group I, are abundant in deep waters where they can fix dissolved inorganic carbon. Viruses appear to be important in the microbial loop in deep waters, displaying remarkably high virus to prokaryote abundance ratios in some oceanic regions. Sequencing of 18S rRNA genes revealed a tremendous diversity of small-sized protists in bathypelagic waters. Abundances of heterotrophic nanoflagellates (HNF) and ciliates decrease with depth more steeply than prokaryotes; nonetheless, data indicated that HNF consumed half of prokaryote production in the bathypelagic zone. Aggregates are important habitats for deep-water microbes, which produce more extracellular enzymes (on a per-cell basis) than surface communities. The theory of marine gel formation provides a framework to unravel complex interactions between microbes and organic polymers. Recent data on the effects of hydrostatic pressure on microbial activities indicate that bathypelagic microbial activity is generally higher under in situ pressure conditions than at atmospheric pressures. High-throughput sequencing of 16S rRNA genes revealed a remarkable diversity of Bacteria in the bathypelagic ocean. Metagenomics and comparative genomics of piezophiles reveal not only the high diversity of deep sea microbes but also specific functional attributes of these piezophilic microbes, interpreted as an adaptation to the deep water environment. Taken together, the data compiled on bathypelagic microbes indicate that, despite high-pressure and low-temperature conditions, microbes in the bathypelagic ocean dynamically interact with complex mixtures of organic matter, responding to changes in the ocean’s biogeochemical state.  相似文献   

18.
A quantitative study on the community structure and biodiversity of free-living marine nematodes and their relationship with environmental factors in the northern South China Sea were carried out based...  相似文献   

19.
Climate change presages increasingly ice-free waters in the Canadian Arctic and fundamental reconfiguration of Asia–Europe and Asia–US East Coast marine transportation networks via the Northwest Passage (NWP). Retreating sea ice will impact the annual re-supply of goods to northern communities, natural resource development, cruise ship and adventure tourism activity, and the fishing industry. Reviews of infrastructure to support increased shipping activity and support future developments highlight an ageing Canadian Coast Guard (CCG) icebreaker fleet. This paper aims to debate the need for, and provision, ownership and management of Arctic icebreaking services required to serve a NWP. It reports perceptions by 110 experts of future marine activity in the Canadian Arctic and CCG services, principally Arctic icebreaking, in terms of their effectiveness and efficiency. The extent of possible private involvement is identified and evaluated. The requirements needed to ensure timely and uninterrupted marine transportation from vessels operating in these waters are highlighted.  相似文献   

20.
We improve and extend the set of parametrizations of chemical and biological processes governing the assimilation of the emulsion-dissolved fraction of hydrocarbons in marine media with regard for the oxidation-reduction conditions in the oxycline and in the aerobic, suboxic, and anaerobic zones of the Black Sea. The numerical experiments aimed the reconstruction of the vertical and spatial distributions of hydrocarbons are performed. The increase in the number of fractions of hydrocarbons from three to five, taking into account the influence of the concentration of oxygen, and the analysis of the processes of anaerobic and photochemical oxidation of hydrocarbons make it possible to construct a numerical model of distribution of hydrocarbons in the aerobic and anaerobic waters of the sea and get good quantitative agreement between the results of numerical experiments and the data of observations. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 6, pp. 53–67, November–December, 2006.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号