An integrated approach to assess the ecological and chemical status of lakes with HOD/AHOD: a case study of two lakes     

Serdar G?NCü  Erdem ALBEK 《中国海洋湖沼学报》2019,37(1):146-159

The thermal strati?cation of the lakes impedes the transfer of atmospheric oxygen into the lower layers of the lake. In lakes which are af fected by diverse anthropogenic in?uences, the increasing organic matter amounts lead to a sharp decrease in hypolimnetic oxygen amounts, aided by thermal strati?cation,and anaerobic conditions arise. The determination of hypolimnetic oxygen demand(HOD) and areal hypolimnetic oxygen demand(AHOD) and their monitoring represent an integrated approach to investigate the oxygenation of lakes, the nutrient conditions, and the physicochemical dynamics. In this study, two lakes dif fering by size and af fected by dif ferent anthropogenic sources, are investigated in this respect. At?rst, bathymetric studies were conducted to determine the depth, surface area, and volume relationships.Then, based on monitoring studies conducted in 2013 and 2014, the thermal strati?cation dynamics and layer properties were established using the relative thermal resistance to mixing(RTRM) index based on temperature and density pro?les. Following this, the oxygen depletion rates were determined by oxygen and temperature pro?ling in the hypolimnion. For the years of 2013 and 2014, the AHOD values for the Borabey Pond which is far from anthropogenic in?uences, were found to be 0.848 and 0.569 g O 2/(m·d), respectively.The AHOD values for the Porsuk Reservoir which was overburdened for years by industrial and domestic pollution were found to be 4.263 and 5.099 g O 2/(m·d), larger than its counterpart by almost sevenfold. The HOD and AHOD monitoring can be considered to a valuable tool for assessing the ecological and chemical status of lakes within Annex 5 of the Water Framework Directive and as an integrated approach to assess and monitor the status of lakes.  相似文献   

140kaBP以来南海西南部上升流影响区沉积记录及其古海洋环境变化   总被引：1，自引：0，他引：1  

邹杨浩  冉莉华  Martin G Wiesner  刘飞  梁文  陈建芳  刘连文 《海洋地质与第四纪地质》2019,39(2):123-133

对南海西南部现代上升流区沉积物柱样BIS-187-61孔有机碳、生物蛋白石、碳酸盐等各沉积组分进行了详细的分析,试图探讨末次间冰期(MIS 5)以来南海西南部夏季上升流影响区沉积过程及其所反映的海洋环境变化过程。研究结果发现,140kaBP以来该孔沉积记录期总体表现为:碳酸盐百分含量冰期低间冰期高,主要受周边陆源物质输入稀释的控制,为典型的"大西洋型碳酸盐旋回",有机碳、生物蛋白石、碳酸钙以及陆源沉积物的堆积速率均在MIS 2期、MIS 4期和MIS 5e期出现高值。其中,MIS 2期和MIS 4期生源和陆源沉积堆积速率增加可能与冰期时冬季风增强及海平面下降导致陆源营养物质输入增加对初级生产力的刺激有关,也可能与陆源物质输入增加对海洋生源颗粒物输出的压载作用增强有关。而MIS 5e期南海海平面高度与现代相仿,间冰期较强的夏季风引起的越南沿岸上升流增强是导致该时段本研究区域表层初级生产力增强,沉积物总堆积速率及各组分堆积速率都相应增加的主要原因。  相似文献   

Challenges in the Detection and Attribution of Northern Hemisphere Surface Temperature Trends Since 1850     

Ronan Connolly  Willie Soon  Michael Connolly  Sallie Baliunas  Johan Berglund  C. J. Butler  Rodolfo Gustavo Cionco  Ana G. Elias  Valery M. Fedorov  Hermann Harde  Gregory W. Henry  Douglas V. Hoyt  Ole Humlum  David R. Legates  Nicola Scafetta  Jan-Erik Solheim  László Szarka  Víctor M. Velasco Herrera  Hong Yan  Weijia Zhang 《天文和天体物理学研究(英文版)》2023,(10):369-388

Since 2007, the Intergovernmental Panel on Climate Change(IPCC) has heavily relied on the comparison between global climate model hindcasts and global surface temperature(ST) estimates for concluding that post-1950s global warming is mostly human-caused. In Connolly et al., we cautioned that this approach to the detection and attribution of climate change was highly dependent on the choice of Total Solar Irradiance(TSI) and ST data sets.We compiled 16 TSI and five ST data sets and found by alter...  相似文献   

Effect of Matching Algorithm and Profile Shape on Pulsar Pulse Time of Arrival Uncertainties     

J.Wang  J.P.W.Verbiest  G.M.Shaifullah  J.P.Yuan 《天文和天体物理学研究(英文版)》2023,(12):232-243

For high-precision pulsar timing analysis and low-frequency gravitational wave detection, it is essential to accurately determine pulsar pulse times of arrival(ToAs) and associated uncertainties. To measure the ToAs and their uncertainties, various cross-correlation-based techniques can be employed. We develop methodologies to investigate the impact of the template-matching method, profile shape, signal-to-noise ratio of both template and observation on ToA uncertainties. These methodologies are...  相似文献   

煤矿区碳排放的确认和低碳绿色发展途径研究     

王猛  马如英  代旭光  单雅迪 《煤田地质与勘探》2021,49(5):63-69

开展煤矿区碳排放的系统评价和减排路径的综合分析,是落实我国碳达峰与碳中和愿景的具体行动。针对煤矿区碳排放源边界不清、核算模型缺乏及碳中和背景下发展方向等问题开展分析。通过文献查阅、资料收集等方法,厘清煤矿区碳排放源边界,并建立碳排放量核算模型,明确煤矿区低碳绿色发展方向。结果表明:煤矿区碳排放(CH₄和CO₂)来源可划分为自然排放和人为排放两大类,并细分为5种类型,针对不同碳排放源提出相应的数学模型;同时煤矿区要加大节能和低碳技术的投入,提高综合资源的利用程度和瓦斯的监测力度,加强绿色矿山修复和建设,积极参与碳市场和碳排放权交易及培育适应市场的管理模式等一系列措施,逐步实现低碳、绿色产业体系;此外,煤矿相关单位应高瞻远瞩,深入分析并发挥政府的低碳环保政策的作用,与相关高校加强合作,在我国碳减排目标下,大力推动煤制氢技术的发展,突破CO₂-ECBM和CCUS关键技术中的运输、封存选址、安全稳定性评价、成本降低等瓶颈问题,以期在双碳背景下碳减排过程中实现经济、环保双重效益。   相似文献   

藏北高原地壳及上地幔导电性结构——超宽频带大地电磁测深研究结果   总被引：27，自引：14，他引：13       下载免费PDF全文

魏文博  金胜  叶高峰  邓明  谭捍东  Martyn Unsworth  Alan G.Jones  John Booker  Shenghui Li 《地球物理学报》2006,49(4):1215-1225

为了研究西藏中、北部壳、幔导电性结构,讨论高原中、北部岩石圈热状态,1998年和1999年（INDEPTH（Ⅲ） MT）在西藏中、北部完成了德庆—龙尾错（500线）和那曲—格尔木（600线）超宽频带大地电磁深探测剖面的研究.研究结果表明,西藏中、北部以昆仑山断裂为界,其南北壳、幔电性结构有很大差异.昆仑山断裂以北地壳和上地幔为高阻区.而昆仑山以南,地壳和上地幔的导电性有明显的分层结构：地壳上部以不连续的高阻体为主,夹有局部低阻异常体,沿南北方向上地壳的电性结构复杂,具有不连续、分块的特点;但中、下地壳为大范围的高导异常区,区内发育有大规模、不相连续、产状各异的高导体,其电阻率均小于4Ωm;在班公—怒江和金沙江缝合带之下,壳内高导体都具有向上地幔延伸的趋势,存在连通壳、幔的低阻通道.根据西藏高原中、北部壳、幔电性结构的研究推断：如同藏南一样,这里也普遍存在部分熔融体和热流体,它们的成因主要与班公—怒江和金沙江缝合带的壳-幔热交换、热活动有关,这是两期形成的壳-幔热交换通道.其中,班公—怒江缝合带的壳-幔热交换通道形成时间比金沙江缝合带早.因此,研究区壳、幔的热活动是从南边和西边开始,向北、向东扩展,导致现今西藏中、北部地壳和上地幔的热流分布由西向东、由南向北增大.  相似文献   

辽宁省重点金矿集区地质特征及成岩成矿作用     

袁和  白银增  耿树峰  洪秀伟  王登红 《中国地质调查》2023,(4):37-45

作为我国重要的产金省份,辽宁省的中生代构造、岩浆活动较为强烈,并伴有强烈的金成矿作用。根据金矿床的空间分布特征,将辽宁省划分出5个重点金矿集区,为深入了解各金矿集区内金矿床的成岩成矿作用,对金矿集区的地质特征、成岩成矿时代、地球化学等方面进行了系统分析。研究表明：各金矿集区的金成矿作用与印支期、燕山期岩浆活动有关,成矿时间集中于126～118 Ma、225～188 Ma;辽西金矿集区金矿石中的S属于地幔硫,而辽东金矿集区S来源于岩浆和变质岩地层,各矿集区矿石的Pb具有壳幔混合源特征,5个重点金矿集区的成矿物质源区组成为同一岩浆源区、不同岩浆演化阶段的产物,成岩成矿物质为下地壳部分熔融的产物,并有部分幔源物质参与。结合近年找矿进展,建立了辽宁省金矿找矿预测地质模型,可为下一步开展区域矿产勘查工作提供新思路。  相似文献   

渤海海域浮游病毒和浮游细菌的丰度变化与环境因子之间的耦联关系     

王彩霞  吴霖  王毅波  Paterson James S.  Mitchell James G.  胡晓珂 《海洋学报(英文版)》2020,39(6):72-83

Uncovering the role of environmental factors and finding critical factors which harbor significant fractions in governing microbial communities remain key questions in coastal marine systems. To detect the interactions between environmental factors and distributions of virio-and bacterioplankton in trophic coastal areas, we used flow cytometry to investigate the abundance of virio-and bacterioplankton covering 31 stations in the Bohai Sea of China. Our results suggested that the average abundance of total virus(TV) in winter(～2.29×10~8 particles/mL)was slightly lower than in summer(～3.83×10~8 particles/mL). The mean total bacterial abundance(TB) was much lower in winter(～2.54×107 particles/mL) than in summer(～5.43×10~7 particles/mL). Correlation analysis via redundancy analysis(RDA) and network analysis among virioplankton, bacterioplankton and environmental factors revealed that the abundances of viral and bacterial subpopulations depend on environmental factors. In winter, only temperature significantly influenced the abundances of virio-and bacterioplankton. In summer, in addition to temperature, both salinity and nutrient(SiO_2) had a remarkable impact on the distribution of virioand bacterioplankton. Our results showed a clear seasonal and trophic pattern throughout the whole water system, which revealed that temperature and eutrophication may play crucial roles in microbial distribution pattern.  相似文献   

地下水气体组分的潮汐变化     

F.Tsunomori  K.Kawai  G.Igarashi  孙小龙 《国际地震动态》2006,(7):144-144

我们观察了日本中部Omaezaki地区地下水气体组分时间序列数据的周期性变化,Omaezaki是日本地震预报目录中即将到来的Tokai地震前兆信号观察的重要地区.我们已经开始在一口100 m深的井中对地下水中气体组分进行持续监测.  相似文献   

台风波浪数值预报的CHGS法：Ⅲ,风浪的成长和涌浪的消衰   总被引：2，自引：0，他引：2  

隋世峰  章家琳 《热带海洋》1989,8(2):13-20

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