共查询到18条相似文献，搜索用时 93 毫秒
1.
湖泊沉积物—水界面营养元素的生物地球化学作用和环境效应：I.界面… 总被引：3，自引：0，他引：3
发生在沉积物－水界面的剧烈生物地球化学作用对沉积物和上覆水体具重要的环境效应，然而此方面研究很少，本文通过云贵高原四个湖泊湖水和孔隙水ＮＨ４和ＮＯ３剖面，沉积物柱芯不同结合态氮含量剖面分布，界面扩散通量，影响氮循环的因素及它们季节性变化规律等的对比研究，初步揭示了湖泊沉积物－水界面的氮循环及其环境效应。 相似文献
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湖泊沉积物—水界面铁—锰循环研究新进展 总被引：18，自引：2，他引：18
通过云贵高原深水湖泊沉积物－水界面铁－锰循环研究，揭示了湖泊铁－锰循环不仅受氧化还原边界层化学界面的控制，而且受沉积物－水地质界面的制约；有机质生物氧化和硫酸盐还原构成界面铁－锰循环的重要机制并产生亚扩散层屏蔽效应；铁－锰循环伴随有微量金属元素地球化学形态的改变，从而影响其迁移行为；气候剧烈变化所中断的铁－锰循环，形成铁－锰富集层的古环境记录。 相似文献
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云贵高原湖泊沉积物——水界面铁,锰,硫体系的研究进展 总被引：13，自引：0，他引：13
通过对云贵高原湖泊沉积物－水界面铁,锰,硫体系的研究,揭示了湖泊铁,锰循环受氧化还原边界层、沉积物－水界面等多重界面的控制;湖水中硫酸盐的浓度制约着其扩散的物理过程,进而影响着硫酸盐还原作用,硫酸盐还原对铁、锰循环产生亚扩散层屏蔽效应,铁,锰的季节性污染等提供了科学依据。 相似文献
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万曦 《矿物岩石地球化学通报》1994,(3)
阿哈湖沉积物─水界面Ｆｅ－Ｍｎ循环的微生物影响分析万曦（中国科学院地球化学研究所，贵阳５５０００２）关键词阿哈湖，沉积物，Ｆｅ－Ｍｎ循环，微生物微生物参与的湖泊沉积地球化学作用在沉积物－水界面物质循环中具有重要意义。本文通过贵阳阿哈湖沉积物－水界面Ｆ... 相似文献
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SWB—1型便携式湖泊沉积物—界面水取样器的研制 总被引：35，自引：1，他引：34
在湖泊环境的研究中,采到保持原状的沉积物－水界面样品是一项基本工作。根据国外有关资料,在前期研制的沉积物－水界面采样装置的基础上,研制成功了一种新型湖泊沉积物－水界面取样器。本取样器由部分组成,即连接构件、配重、悬挂密封机构和取样管。取样器是靠自重插入湖泊沉积层,悬挂密封机构将样品封闭于取样管内。本取样器能在深水湖泊中取到３０￣５０ｃｍ的湖底沉积物柱及１０￣３０ｃｍ的界面水柱。整个取样器重量轻（只 相似文献
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为有效控制湖泊内源营养盐的释放,探讨了不同物理改良措施(覆沙、底质疏松)对沉积物-水界面营养盐的释放通量控制效果。利用原位孔隙水采样技术(Peeper)来获得沉积物孔隙水剖面,对改良后湿地沉积物孔隙水营养盐的垂向分布及其扩散通量进行了研究。结果发现,改良后沉积含水率、孔隙率分别提高了91%和54%。水土界面附近,随剖面深度增加,孔隙水中PO43-、NH4+、NO3-及NO2-浓度分布符合指数关系,PO43-、NH4+在8 cm左右达到最大值。种植芦苇后沉积物孔隙水中PO43-、NH4+均有不同程度的下降,改良措施能有效降低表层弱结合态磷在总磷中比例但增加铁磷的比例,种植芦苇可强化这一效应。运用Fick第一定律对剖面孔隙水营养盐的扩散通量进行估算,发现沉积物经疏松后,NH4+、PO43-的扩散通量由57.47~72.19μg/(m2·d)和2.55~3.21μg/(m2·d)变为-95.54~-130.94μg/(m2·d)和1.50~2.05μg/(m2·d),可考虑疏松沉积物-水界面附近沉积物来作为控制湖泊内源污染的有效手段之一。 相似文献
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生物膜作用下沉积物-水界面溶液中pH和磷含量变化 总被引：1，自引：0，他引：1
采集城市排污水渠中的沉积物样品和底栖生物样品,应用微电极原位pH测量技术测量沉积物-水界面溶液的pH值,电感耦合等离子体发射光谱法测定沉积物提取液中上覆水和空隙水中生物可利用磷的含量,研究了沉积物表面的生物膜对城市河流沉积物-水界面微环境中pH值和磷含量的影响。研究表明沉积物表面的生物膜由藻类(蓝藻门颤藻属Oscillatoria和硅藻门的菱形藻Nitzschia)和微生物组成,由于藻类的光合作用和微生物作用,沉积物空隙水中的溶解氧和CO2发生变化,因而改变了界面附近的pH值、氧化还原电位等物理化学条件,同时改变了界面附近溶液中磷的浓度和浓度梯度。在生物膜作用下,剖面中空隙水的pH和pH变化梯度、磷的浓度和浓度梯度高于非生物作用条件下。磷在生物藻垫的空隙水中高度富集。在生物膜存在情况下,在空隙水中形成了与非生物作用下相反的pH值和磷浓度的耦合关系。无生物作用的沉积物空隙水中pH越偏离中性,沉积物中磷的释放量增加,空隙水中磷含量增加;在生物膜作用下,pH由弱酸性向中性变化时,沉积物中磷的释放量增加,空隙水中磷含量增加。依据界面附近pH值和磷的变化规律,可以将沉积物-水界面附近的生物作用分为生物膜的固定作用区和攫取作用区。 相似文献
10.
沉积物-水界面的生物地球化学作用 总被引：18，自引：0，他引：18
沉积物－水界面是天然水体在物理、化学和生物特征等方面差异性最显著和负责水体和沉积物之间物质输送和交换的重要边界环境。对沉积物－水界面生物地球化学的定义、研究方法和它在水体微量物质循环中所起的作用、物质迁移方式、典型氧化还原敏感性元素转化反应（Ｃ、Ｏ、Ｎ）、界面扩散通量和表面扩散亚层的意义和估算等进行了讨论。 相似文献
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喀斯特生态系统生物地球化学过程与物质循环研究:重要性、现状与趋势 总被引：9，自引：0，他引：9
喀斯特地质与生态系统是地球表层系统中的重要组成部分,其变化将对其他地区以及整个地球系统产生影响.生物地球化学循环是全球和区域变化研究的核心内容,而生态系统的演化与系统内水分和养分的生物地球化学循环密切相关。因此,我们有必要将喀斯特生态系统纳入到更大区域或全球生态系统中进行分析研究,在充分研究认识整个喀斯特生态系统物质生物地球化学循环规律的基础上,进一步研究喀斯特生态系统的全球变化响应或影响机制,为喀斯特生态系统优化调控对策和措施提供科学基础。研究生态系统演化过程中物质的生物地球化学循环规律,是研究植物适生性、物种优化配置和适应性生态系统调控机理的关键基础。在介绍前人工作基础的同时,本文全面而概括地总结了我们近年利用元素、同位素(如δ13C、δ15N、δ34S、87Sr/86Sr)示踪和化学计量学理论和方法对喀斯特生态系统中不同界面和流域中物质的生物地球化学循环及其生态环境效应的研究成果。认识到:喀斯特流域生物地球化学循环活跃,相互耦合,并与流域生态环境变化相互制约;人类活动正干预流域物质的自然生物地球化学循环过程,并导致相应的生态和环境效应;全球变化科学深化有赖于区域生态环境变化及物质生物地球化学循环的研究。这些认识是我们将来系统深入开展喀斯特以及其他流域生态系统物质生物地球化学循环研究的重要方向。 相似文献
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Persistent Organic Pollutants （POPs） have caused great public concern during the past decade. To address this global public concern, China joined international forces to sign a groundbreaking United Nations treaty in Stockholm, known as the Stockholm Convention. The Chinese Government agreed to reduce and eliminate the production, use or release of 12 key POPs. Because the convention specifies a scientific review process for all other compounds, the addition of other POPs of global concern to the list in the future is also possible. The most possible candidate compounds are some species used as polybrominated flame retardant and perfluronated compounds, called emerging chemicals. Most emerging chemicals are those with POP-like characteristics, they are persistent in the environment; travel over long distances via air and water; toxic and bioaccumulating in living things. Those chemicals pose an unacceptable threat to human health and the environment. 相似文献
13.
Jeffrey G. Catalano Paul Fenter Changyong Park 《Geochimica et cosmochimica acta》2007,71(22):5313-5324
Many geochemical reactions that control the composition of natural waters, contaminant fate and transport, and biogeochemical element cycling take place at the interface between minerals and aqueous solutions. A fundamental understanding of these important processes requires knowledge of the structure of mineral-water interfaces. High-resolution specular X-ray reflectivity was used to determine the structure of the hematite (0 1 2)-water interface. Relaxation of the surface was observed to be minor, and water was found to order near the hematite surface. Two sites of adsorbed water are inferred to be ordered laterally, one bridging between triply coordinated functional groups and the other bridging between the singly coordinated functional groups on the surface, as steric constraints limit the possible arrangements of water molecules occurring at the observed heights above the hematite surface. Relaxations of the hematite and corundum (0 1 2) surfaces, which are isostructural, are similar and limited primarily to the top most layer of the structures. No significant changes to the interfacial stoichiometry (i.e., partial occupancy of surface species) are observed in either case. The structure of interfacial water is similar on the hematite and corundum (0 1 2) surfaces as well, although water appeared to be less well ordered on the hematite surface. This may be due to expected differences in the oxygen exchange rates from surface functional groups or the apparent better matching of the corundum oxygen lattice to the natural structural ordering in water, and suggests that the dielectric constant gradients of interfacial water may differ on the two surfaces. Similar charging behavior is expected for these surfaces as similar types of surface functional groups are exposed. Although generally similar, subtle differences in the reactivity of hematite and corundum (0 1 2) surfaces to arsenate adsorption, and possibly the adsorption of other species, may be related to the difference in ordering of interfacial water observed in this study. 相似文献
14.
河口沉积物—水界面重金属生物地球化学研究进展 总被引：15，自引：1，他引：15
河口区既是人类排污物的主要汇集地，又是单向流体和双向流体相互作用的场所，三者构成一个复杂而多变的地球化学物理场。在这里因一定的物理，化学和生物化学作用使来自陆地的重金属污染物从水体中沉降下来，进入底部沉积物即积累过程，又会因类似的作用使这些金属从沉积物中活化而再次进入水体即释放过程，产生所谓的“二次污染”，河口沉积物水界面过程调控着这一体系的方向与限度。 相似文献
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Jianghua Wu 《Environmental Earth Sciences》2012,65(1):141-151
Peatlands contain approximately 25% of the total soil organic carbon, despite covering only 3% of earth’s land surface. The
ecological, hydrological and biogeochemical functions of peatlands are tightly coupled to climate. Therefore, both direct
human impacts and indirect effects of climate change can threaten the ecological function of peatlands through changes in
hydrology. However, little is known about how peatland ecosystems, and specifically their biogeochemistry, carbon cycling,
and development, may respond to climatic change. In this study, the Peat Accumulation Model was adapted to investigate the
response of peatland development and carbon cycling to climatic change through simulating changes in precipitation and temperature
at different stages of peatland development history. The warming and wetting were imposed on this system at 10,000 years since
its initialization (mid-development stage) and at 20,000 years since its initialization (late-development stage). Here, it
was revealed that peatlands can switch between carbon sinks and sources suddenly, but the extent to which the change takes
place depends on the developmental stage of peatland ecosystems. The simulation results for the late-development stage showed
that peatlands could function as carbon sources once warming and wetting was imposed but that peatland ecosystems during the
mid-development stage can still function as carbon sinks under warming and wetting conditions. Moreover, peatland ecosystems
have self-regulation capabilities so that they can go back to their normal ecological and biogeochemical functions under newly
stabilized climates. Also, it is the change in temperature that results in the fundamental change in peatland development
and carbon cycling. This study indicates that the response of peatland ecosystems to climate change is largely determined
by their developmental stages. 相似文献
16.
生物地球化学循环是地球系统物质循环的核心,是维系地表生态系统稳定和人类社会可持续发展的重要基础。然而,气候变化以及人类的过度干扰可能会显著改变表层地球系统中的生物地球化学循环过程,尤其是脆弱的喀斯特生态系统。特殊的多孔隙关键带结构也加速了喀斯特地区物质循环及其对外界环境变化的响应,影响了不同尺度的物质循环和生物地球化学过程。本研究主要综述了宏观尺度（气候变化）、中尺度（人类活动）和微观尺度（微生物活动）的环境变化对喀斯特地区生物地球化学循环的影响。结果表明多要素变化导致喀斯特地区物质循环受到强烈影响,气候变化、人类活动和微生物活动及其耦合关系对喀斯特地区生物地球化学循环的调控作用具有重要意义。最后,本研究强调了现有研究的局限性并指出未来研究的挑战与方向,即未来应从系统研究（如地球关键带）的视角出发,将多尺度观测－分析与综合模型集成研究并举,从而构建多源多尺度耦合的过程和系统模型,进而为阐明喀斯特系统的演变规律和动力学机制、实现喀斯特地区的生态保护和高质量发展提供理论基础。 相似文献
17.
硅元素是地球第二大组成元素,深刻影响着地表物质循环,是陆海相互作用研究、全球碳循环研究的关键元素之一.从自然风化、生物过程和人类活动3个方面综述了国内外有关地表过程对硅产出影响的研究进展,重点分析了生物过程和人类活动在硅生物地球化学循环过程中的作用.综合分析指出,应着重开展生物参与下原生/次生硅酸盐矿物风化速率的研究,重视高等植物在区域硅循环中的作用;富营养化与筑坝对于河流硅的滞留都十分重要,因筑坝产生的水库清水下泄在中下游河道产生的潜在效应很可能对河口硅输入产生重要的影响.应采用地球化学示踪技术,加强这方面的定量研究、模型研究、过程研究以及系统的综合性研究,特别是对流域地表过程的改变以及与筑坝、富营养化过程的联合作用,应进行深入的多学科交叉综合研究. 相似文献
18.
Nitrogen (N) is one of the primary nutrients required to build biomass and is therefore in high demand in aquatic ecosystems. Estuaries, however, are frequently inundated with high concentrations of anthropogenic nitrogen, which can lead to substantially degraded water quality. Understanding drivers of biogeochemical N cycling rates and the microbial communities responsible for these processes is critical for understanding how estuaries are responding to human development. Estuaries are notoriously complex ecosystems: not only do individual estuaries by definition encompass gradients of salinity and other changing environmental conditions, but differences in physical parameters (e.g., bathymetry, hydrodynamics, tidal flushing) lead to a tremendous amount of variability in estuarine processes between ecosystems, as well. Here, we review the current knowledge of N cycling processes in estuaries carried out by bacteria and archaea, including both biogeochemical rate measurements and molecular characterizations of N cycling microbial communities. Particular attention is focused on identifying key environmental factors associated with distinct biogeochemical or microbial regimes across numerous estuaries. Additionally, we describe novel metabolisms or organisms that have recently been discovered but have not yet been fully explored in estuaries to date. While the majority of research has been conducted in the benthos, we also describe data from estuarine water columns. Understanding both the common patterns and the differences between estuaries has important implications for how these critical ecosystems respond to changing environmental conditions. 相似文献