Possible link between new coronavirus variants and atmospheric lightning and seawater intrusion          下载免费PDF全文

Jianping Huang  Yingjie Zhao  Danfeng Wang 《大气和海洋科学快报》2022,15(1):100135

自新型冠状病毒肺炎暴发一年多以来,已经对全球产生深远影响.新型冠状病毒肺炎变异毒株的出现使当前疫情发展充满了不确定性.从这方面出发,我们讨论病毒变异与大气因素之间的联系.根据固氮过程和硝酸盐在人体中的转化过程,我们提出了新型冠状病毒肺炎变异毒株的出现或许和闪电以及海水入侵有联系.我们的研究对新型冠状病毒肺炎变异毒株可能的产生原因提供新的观点.  相似文献   

江苏海域水环境要素分析——江苏海域环境质量分析之二   总被引：3，自引：0，他引：3       下载免费PDF全文

丁贤荣  张鹰 《海洋科学》2003,27(2):8-12

在1981、1991（1990）和1998年3次海洋环境调查的基础上，通过相同水质要素时空比较分析，江苏海域的溶解氧、磷酸盐、硝酸盐和亚硝酸 盐这4种主要海水化学因子具有时空变化特征，其高值区主要分布在灌河口、扁担港口、射阳河口、川东港和长江北支口北侧，且河口、近岸值高，向海含量渐小，不同年份、季节也有变化。沿海水化学性质主要受陆源排污（农田化肥等）影响，主要是入海河流携带污染物、海洋生物作用和本海域水体运动特征的影响，此外，溶解氧变化还受到水温变化的影响。  相似文献   

Primary production in the eastern tropical Pacific: A review   总被引：2，自引：12，他引：2  

J. Timothy Pennington  Kevin L. Mahoney  Victor S. Kuwahara  Dorota D. Kolber  Ruth Calienes  Francisco P. Chavez   《Progress in Oceanography》2006,69(2-4):285

The eastern tropical Pacific includes 28 million km² of ocean between 23.5°N and S and Central/South America and 140°W, and contains the eastern and equatorial branches of the north and South Pacific subtropical gyres plus two equatorial and two coastal countercurrents. Spatial patterns of primary production are in general determined by supply of macronutrients (nitrate, phosphate) from below the thermocline. Where the thermocline is shallow and intersects the lighted euphotic zone, biological production is enhanced. In the eastern tropical Pacific thermocline depth is controlled by three interrelated processes: a basin-scale east/west thermocline tilt, a basin-scale thermocline shoaling at the gyre margins, and local wind-driven upwelling. These processes regulate supply of nutrient-rich subsurface waters to the euphotic zone, and on their basis we have divided the eastern tropical Pacific into seven main regions. Primary production and its physical and chemical controls are described for each.Enhanced rates of macronutrient supply maintains levels of primary production in the eastern tropical Pacific above those of the oligotrophic subtropical gyres to the north and south. On the other hand lack of the micronutrient iron limits phytoplankton growth (and nitrogen fixation) over large portions of the open-ocean eastern tropical Pacific, depressing rates of primary production and resulting in the so-called high nitrate-low chlorophyll condition. Very high rates of primary production can occur in those coastal areas where both macronutrients and iron are supplied in abundance to surface waters. In these eutrophic coastal areas large phytoplankton cells dominate; conversely, in the open-ocean small cells are dominant. In a ‘shadow zone’ between the subtropical gyres with limited subsurface ventilation, enough production sinks and decays to produce anoxic and denitrified waters which spread beneath very large parts of the eastern tropical Pacific.Seasonal cycles are weak over much of the open-ocean eastern tropical Pacific, although several eutrophic coastal areas do exhibit substantial seasonality. The ENSO fluctuation, however, is an exceedingly important source of interannual variability in this region. El Niño in general results in a depressed thermocline and thus reduced rates of macronutrient supply and primary production. The multi-decadal PDO is likely also an important source of variability, with the ‘El Viejo’ phase of the PDO resulting in warmer and lower nutrient and productivity conditions similar to El Niño.On average the eastern tropical Pacific is moderately productive and, relative to Pacific and global means, its productivity and area are roughly equivalent. For example, it occupies about 18% of the Pacific Ocean by area and accounts for 22–23% of its productivity. Similarly, it occupies about 9% of the global ocean and accounts for 10% of its productivity. While representative, these average values obscure very substantial spatial and temporal variability that characterizes the dynamics of this tropical ocean.  相似文献   

The dynamics of the carbon cycle in the surface water of the Norwegian Sea     

Eva Falck  Leif G. Anderson   《Marine Chemistry》2005,94(1-4):43

Historical data of total dissolved inorganic carbon (C_T), together with nitrate and phosphate, have been used to model the evolution of these constituents over the year in the Atlantic water of the Norwegian Sea. Changes in nutrient concentration in the upper layer of the ocean are largely related to biological activity, but vertical mixing with the underlying water will also have an impact. A mixing factor is estimated and used to compute the entrainment of these constituents into the surface water from below. After taking the mixing contribution into account, the resulting nutrient concentration changes are attributed to biological production or decay. The results of the model show that the change in C_T by vertical mixing and by biological activity based on nutrient equivalents needs another sink to balance the carbon budget. It cannot be the atmosphere as the surface water is undersaturated with respect to carbon dioxide and is, thus, a source of C_T in this region. Inasmuch as the peak deficit of carbon is more than a month later than for the nutrients, the most plausible explanation is that other nitrogen and phosphate sources than the inorganic salts are used together with dissolved inorganic carbon during this period. As nitrate and phosphate show a similar trend, it is unlikely that the explanation is the use of ammonia or nitrogen fixation but rather dissolved organic nitrogen and phosphate, while dissolved organic carbon is accumulating in the water.  相似文献   

赤潮发生机理研究──海洋原甲藻的氮营养生理特征   总被引：17，自引：1，他引：17  

黄晓航  史冬梅  张京浦  刘海航  吴超元 《海洋与湖沼》1997,28(1):33-38

于１９９１年１月－１９９１年１２月，以不同浓度的硝态氮（２０，６０，２００，６００μｍｏｌ／Ｌ）研究对赤潮生物海洋原甲藻的生长和生化组成的影响，及其营养生理特性，结果表明，在氮浓度为２００和６００μｍｏｌ／Ｌ时，表现光合作用强，细胞生长快，指数生长期长，叶绿素含量高，提示了由原甲藻爆发引起的赤潮与海洋富营养化有直接关系，结果还表明，海洋原甲藻可以累积蛋白质和碳水化合物，当外界氮源不能满足生长需要时  相似文献   

粘土矿物对海水中主要营养盐的吸附研究   总被引：20，自引：1，他引：20  

俞志明  马锡年  谢阳 《海洋与湖沼》1995,26(2):208-214

对海水中磷盐和硝酸盐在粘土矿物上的吸附行为的研究发现，海水体系中高岭土对磷酸盐的吸附能力大于蒙脱土，其原因为，粘土颗粒的表层铝／硅结构比是控制磷酸盐吸附的主要因素，其中铝含量越高，肿附能力越大。考察ＰＨ、粘土酸改性处理等因素对吸附作用的影响，结果表明，ＰＨ＜８．５的磷酸盐吸附ＰＨ曲线呈峰形，其吸附作用以阴离子交换为主；ＰＨ＞８．５时磷酸盐的吸附作用以沉淀吸附为主。酸改性蒙脱土可提高吸附磷酸盐的能力  相似文献   

Environmental fate and health exposures of the geogenic and anthropogenic contaminants in potable groundwater of Lower Ganga Basin,India     

《地学前缘(英文版)》2022,13(3):101365

The study evaluated the sources and controlling factors of the groundwater contaminants in an agroeconomic region of Lower Ganga Basin using principal component analysis (PCA), multivariable linear regressions (MLR), correlation analysis, and hierarchical cluster analysis, and evaluated the public health risks using the Latin Hypercube Sampling, goodness-of-fit statistics, Monte Carlo simulation and Sobol sensitivity analysis based on the 1000 samples collected in two sampling cycles (N = 1000). The study reveals that the dissolution of fluoride-bearing minerals and semi-arid climate regulate the fluoride concentrations (0.10–18.25 mg/L) in groundwater. Extensive application of inorganic nitrogenous fertilizers and livestock manure mainly contributed to elevated nitrate levels (up to 435.0 mg/L) in groundwater. The health risks analysis indicates that fluoride exposure is more prevalent in the residents of each age group than the nitrate and both contaminants exhibited higher non-carcinogenic health risks on the infant and child (minor) age groups compared to adolescents and adults. Based on the cokriging interpolation mapping, the minor residents of 17.88%–23.15% of the total area (4545.0 km²) are vulnerable to methemoglobinemia whereas the residents of all age-groups in 38.47%–44.45% of the total area are susceptible to mild to severe dental/skeletal fluorosis owing to consumption of untreated nitrate and fluoride enriched groundwater. The Sobol sensitivity indices revealed contaminant levels, groundwater intake rate and their collective effects are the most influential factors to pose potential health risks on the residents. Artificial recharge and rainwater harvesting practices should be adopted to improve the groundwater quality and the residents are advised to drink purified groundwater.  相似文献   

海水硝酸盐氮、氧同位素组成研究进展   总被引：2，自引：0，他引：2  

杨志  陈敏 《地球科学进展》2012,27(3):268-275

海洋中氮的生物地球化学循环影响着海洋生态系统的结构和功能,并和全球气候变化有着密切的联系,一直是海洋科学研究的重点和热点。海水硝酸盐的15N/14N和18O/16O比值可以反映海洋中氮循环的主要过程,因而成为研究海洋氮循环的一个重要手段。综述海水硝酸盐氮、氧同位素组成的测定方法,同化吸收作用、硝化作用、反硝化作用、生物固氮作用等氮循环过程所导致的氮、氧同位素分馏及其在海洋学研究中的应用。海洋生态系中硝酸盐氮、氧同位素的分布可以提供支持生物生产力的氮来源信息,以及氮在不同储库迁移转化的路径与机制。未来的研究需要发展适用于低含量硝酸盐的同位素测量方法,构筑海洋氮的收支平衡,掌握影响上层海洋硝酸盐氮、氧同位素变化的过程,获取全球海域有关硝酸盐氮、氧同位素组成的更多数据。  相似文献   

氮磷营养盐对中肋骨条藻生长及硝酸还原酶活性的影响   总被引：3，自引：0，他引：3  

王金花  唐洪杰  杨茹君  王修林 《海洋科学》2008,32(12):64-68

通过实验室培养，在不同氮磷浓度及氮磷比率的营养条件下，对中肋骨条藻（Skeletonema costatum）的生长及藻细胞硝酸还原酶的活性进行研究。实验结果表明，中肋骨条藻属于营养型藻类，氮磷营养盐的添加，极大地促进了藻细胞的增殖。在接种后的第4～5天，各培养组藻密度达到最大值并与对照组形成极显著性差异（P〈0．01）。实验进一步发现，环境中的氮、磷浓度及氮磷比率都会影响中肋骨条藻的生长及藻细胞硝酸还原酶活性（NRA）。此外，在各培养组中，中肋骨条藻硝酸还原酶活性的最大值（NRAmax）均出现在指数生长期（接藻后第1，2天），早于最大藻密度的出现时间（第4，5天），这表明藻对营养盐的同化速率与生长速率并不一致，后者存在一定的滞后效应。在本实验条件下，中肋骨条藻的硝酸还原酶活性存在一定的阈值。  相似文献   

Groundwater flow and contaminant transport modelling at an air weapons range     

Geneviève Bordeleau  Richard Martel  Dirk Schäfer  Guy Ampleman  Sonia Thiboutot 《Environmental Geology》2008,55(2):385-396

Numerical modelling was done at the Cold Lake Air Weapons Range, Canada, to test whether the dissolved RDX and nitrate detected in groundwater come from the same sources, and to predict whether contamination poses a threat to the surface water receptors near the site. Military live fire training activities may indeed pose a risk of contamination to groundwater resources, however field investigations on military bases are quite recent, and little information is available on the long-term behaviour of munition residues related contaminants. Very limited information was available about the contaminant source zones, which were assigned based on our knowledge of current training activities. The RDX plume was well represented with the model, but the heterogeneous distribution of nitrate concentrations was more difficult to reproduce. It was nonetheless determined that both contaminants originate from the same areas. According to the model, both contaminants should reach the nearby river, but concentrations in the river should remain very low if the source zone concentration does not change. Finally, the model allowed the recommendation of a new location for the main bombing target, which would offer added protection to the river and the lake into which it flows.  相似文献