Source-to-sink

  • 文章类型: Journal Article
    在2011年3月福岛第一核电站灾难之后,日本政府启动了一项前所未有的净化计划,以修复受137Cs污染的土壤并允许人口返回。该方案涉及清除农田和居住用地下的表土,并将其替换为由花岗岩腐岩组成的“新鲜土壤”。然而,净化仅限于这两种土地用途,没有修复森林,覆盖受影响区域表面积的70%。在这种前所未有的背景下,这一独特的净化方案对河流系统中137Cs转移的具体影响仍有待在集水区规模上量化。在这项研究中,根据对2021年6月在马诺大坝水库中收集的沉积物岩心的分析,该水库排干了一个净化的集水区,回顾性评估了土壤去污对一系列极端降水事件对颗粒结合的137Cs动力学和沉积物源贡献的影响。通过分析几种诊断特性(有机物,元素地球化学,可见比色法,粒度)和上下文信息。放弃期间(2011-2016年),耕地贡献下降(31%)。同时,137Cs活性和沉积通量下降(分别为1年的19%和29%)。净化后(2017年),沉积物转移增加(270%),以响应去污农田和“新鲜土壤”的增加(分别为625%和180%)。同时,森林贡献保持稳定。相比之下,137Cs活动下降(65%),尽管137Cs沉积通量保持恒定。森林是137Cs的稳定来源。因此,净化后的137Cs沉积通量(2016-2021年)与5年土地废弃期间(2011-2016年)观察到的相似,由于农田上自发植被的再生,保护土壤免受侵蚀。未来的研究应进一步调查最近净化的某些地区普遍存在的更长的土地废弃对河流中137Cs通量的影响。
    Following the Fukushima Daiichi Nuclear Power Plant disaster in March 2011, the Japanese government initiated an unprecedented decontamination programme to remediate 137Cs-contaminated soils and allow population return. This programme involved the removal of topsoil under farmland and residential land, and its replacement with \"fresh soil\" composed of granitic saprolite. However, decontamination was limited to these two land uses, without remediating forests, which cover 70 % of the surface area in the affected region. In this unprecedented context, the specific impact of this unique decontamination programme on 137Cs transfers in river systems remains to be quantified at the catchment scale. In this study, based on the analysis of a sediment core collected in June 2021 in the Mano Dam reservoir draining a decontaminated catchment, the effects of soil decontamination on particle-bound 137Cs dynamics and sediment source contributions in response to a succession of extreme precipitation events were retrospectively assessed. The sequence of sediment layer deposition and its chronology were reconstructed through the analysis of several diagnostic properties (organic matter, elemental geochemistry, visible colourimetry, granulometry) and contextual information. During abandonment (2011-2016), cropland contribution decreased (31 %). Concurrently, 137Cs activity and deposition flux decreased (19 and 29%year-1, respectively). Following decontamination (2017), sediment transfer increased (270 %) in response to increased contributions from decontaminated cropland and \"fresh soil\" (625 % and 180 % respectively). Meanwhile, forest contributions remained stable. In contrast, 137Cs activity dropped (65 %), although 137Cs deposition flux remained constant. Forests acted as a stable source of 137Cs. Accordingly, 137Cs deposition flux after decontamination (2016-2021) was similar to that observed during the 5-years period of land abandonment (2011-2016), as a result of the regrowth of spontaneous vegetation over farmland, protecting soil against erosion. Future research should further investigate the impact of longer land abandonment that prevailed in some regions decontaminated lately on the 137Cs fluxes in the rivers.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    漂浮的人为垃圾发生在所有海洋盆地,然而,人们对它们在东非沿海水域的分布和丰度知之甚少。Neuston网和散装水采样显示,中观和微落物(8567±19,684项•km-2,44±195g•km-2)和微纤维(2.4±2.6纤维•L-1)是坦桑尼亚和莫桑比克北部沿海的普遍污染物,坦桑尼亚以外的垃圾负荷较高。雨季开始时,靠近海岸和主要河口的中观和微凋落物的密度更大,这表明很多垃圾可能起源于土地。然而,垃圾的质量随着与六个主要沿海城市的距离而增加。按数量,95%的中观和微垃圾是塑料,但只有6%的微纤维。我们的研究结果强调了减少塑料使用和改善该地区固体废物管理的必要性。
    Floating anthropogenic litter occurs in all ocean basins, yet little is known about their distribution and abundance in the coastal waters off east Africa. Neuston net and bulk water sampling shows that meso- and micro-litter (8567 ± 19,684 items∙km-2, 44 ± 195 g∙km-2) and microfibres (2.4 ± 2.6 fibres∙L-1) are pervasive pollutants off the coasts of Tanzania and northern Mozambique, with higher litter loads off Tanzania. Densities of meso- and micro-litter at the start of the rainy season were greater close to the coast and to major river mouths, suggesting that much litter likely originates on land. However, the mass of litter increased with distance from the six major coastal cities. By number, 95% of meso- and micro-litter was plastic, but only 6% of microfibres. Our results highlight the need to reduce plastic use and improve solid waste management in the region.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    UNASSIGNED:确定沉积物指纹识别或追踪的最佳做法对于量化来自集水区的沉积物贡献非常重要。尽管沉积物指纹技术的应用取得了合理的成功,此方法的部署仍然与许多问题和限制有关。
    UNASSIGNED:在2021年10月为期4天的主题学校期间组织了研讨会和辩论,以提出具体建议,以改善跟踪方法的设计和实施。
    未经批准:首先,我们建议更好地利用地貌信息来改进研究设计。邀请研究人员仔细检查感兴趣的集水区的所有可用知识,并获得有关沉积物来源贡献的多条证据。第二,我们认为科学知识可以通过当地知识得到改善,我们提出了一个参与规模,描述了当地人参与研究的不同程度。第三,我们建议使用最先进的沉积物追踪协议进行采样,处理颗粒大小,并在建模和核算所调查的水文气象背景之前检查数据。第四,我们推广建模方面的最佳实践,包括运行多个模型的重要性,选择合适的示踪剂,并报告模型误差和不确定性。第五,我们建议共享跟踪数据和样本的最佳实践,这将增加地球科学中指纹识别技术的知名度。第六,我们建议更好地制定假设可以更统一地提高我们对侵蚀和泥沙输运过程的认识。
    UNASSIGNED:通过建议的改进,沉积物指纹,本质上是跨学科的,可以在应对当前和未来与全球变化相关的挑战方面发挥重要作用。
    UNASSIGNED:在线版本包含补充材料,可在10.1007/s11368-022-03203-1获得。
    UNASSIGNED: Identifying best practices for sediment fingerprinting or tracing is important to allow the quantification of sediment contributions from catchment sources. Although sediment fingerprinting has been applied with reasonable success, the deployment of this method remains associated with many issues and limitations.
    UNASSIGNED: Seminars and debates were organised during a 4-day Thematic School in October 2021 to come up with concrete suggestions to improve the design and implementation of tracing methods.
    UNASSIGNED: First, we suggest a better use of geomorphological information to improve study design. Researchers are invited to scrutinise all the knowledge available on the catchment of interest, and to obtain multiple lines of evidence regarding sediment source contributions. Second, we think that scientific knowledge could be improved with local knowledge and we propose a scale of participation describing different levels of involvement of locals in research. Third, we recommend the use of state-of-the-art sediment tracing protocols to conduct sampling, deal with particle size, and examine data before modelling and accounting for the hydro-meteorological context under investigation. Fourth, we promote best practices in modelling, including the importance of running multiple models, selecting appropriate tracers, and reporting on model errors and uncertainty. Fifth, we suggest best practices to share tracing data and samples, which will increase the visibility of the fingerprinting technique in geoscience. Sixth, we suggest that a better formulation of hypotheses could improve our knowledge about erosion and sediment transport processes in a more unified way.
    UNASSIGNED: With the suggested improvements, sediment fingerprinting, which is interdisciplinary in nature, could play a major role to meet the current and future challenges associated with global change.
    UNASSIGNED: The online version contains supplementary material available at 10.1007/s11368-022-03203-1.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    基于Cr,Pb,Zn,Cd,以及来自山东半岛北部沿海水域56个采样点的表层沉积物的含量和谷物数据,分析了重金属在沉积物中的分布特征,并讨论了这些元素的来源。结果表明,Cr的分布,Pb,和锌相似,As和Cd的分布与其他三种不同,Cr,Pb,Cd,在邓州浅滩都显示出高浓度。Cr,Pb,Zn,由表层沉积物的细粒成分控制,主要起源于自然过程,由于主要起源于水产养殖,Cd来自自然和人类。重金属的高浓度主要集中在余流汇聚和沿海流作用的地区,重金属的分布与沉积动力环境有很好的相关性。人类活动,因此,晶粒尺寸和水动力条件是影响本研究区域重金属分布的重要因素。
    Based on the Cr, Pb, Zn, Cd, and As content and grain data from the surface sediments of 56 sampling sites in the coastal waters off the northern Shandong Peninsula, the distribution characteristics of heavy metals in sediments were analyzed, and the sources of these elements were discussed. The results show that the distributions of Cr, Pb, and Zn were similar to each other, while the distributions of As and Cd differed from the other three, with Cr, Pb, Cd, and As all showing high concentrations in the Dengzhou shoal. Cr, Pb, and Zn, which are controlled by fine-grained components of surface sediments, mainly originated from natural processes, As mainly originated from aquaculture, and Cd originated from both natural and human sources. The high concentrations of heavy metals were mostly in areas of residual current convergence and coastal current action, and the distribution of heavy metals can be well correlated to the sedimentary dynamic environment. Human activities, grain size and hydrodynamic conditions are therefore important factors that influence the distribution of heavy metals in this study area.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

  • 文章类型: Journal Article
    Most monitoring studies of marine anthropogenic debris have focused on sandy beaches, so little is known about litter on rocky shorelines. We surveyed litter trapped on a rocky intertidal shore in False Bay, South Africa, between May 2015 and March 2018. An exceptional upwelling of seabed litter occurred in November 2017 (70 items∙m-1). Excluding this event, monthly clean-ups at spring low tide collected 2 (1.3-3.1) items∙m-1∙month-1 and 31 (19.4-49.4) g∙m-1∙month-1 of which 74% was plastic (31% by mass). Litter loads peaked in autumn when seasonal rains washed litter into False Bay, suggesting that most litter comes from local land-based sources. Litter composition differed from that on a nearby sandy beach, with more glass and other dense items on the rocky shore, but 60% of plastic items floated in water. Sand inundation and biotic interactions helped to trap buoyant plastics in the intertidal zone.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

       PDF(Pubmed)

  • 文章类型: Journal Article
    Sustainable management of insular beaches, that are critical to tourism-based economies, depends on sound understanding of coastal evolution drivers. However, interconnections among geological, oceanographical, biological and human key-drivers of coastal change, operating at relevant spatial and temporal scales, remains poorly understood. This work aims at understanding and quantifying the main drivers of insular beaches evolution using a past-to-future sediment budget approach, and to address future coastal impacts raised by anthropogenic interventions and climate change. This approach was developed in Porto Santo\'s beach from the early 20th century to the middle 21st century. Results show that anthropic activities undertaken during the late 20th century perturbed the existing long-term (natural) coastal stability. They caused significant reduction of the main sediment source (river sediment yield) and increased sediment sinks (e.g. sediment extraction from beach, harbour sedimentation). Altogether, this resulted in the onset of an erosive trend that persists until present. Projecting patterns of coastal change into the forthcoming decades strongly depends on sediment management strategies. We show that the adoption of a neutral strategy (i.e. compensating for anthropogenic-induced losses with beach nourishment) will not be enough to cease beach erosion, given the negative impacts related to acceleration of future sea level rise. Still, maintenance of the socioeconomic values of Porto Santo\'s beach can be achieved by triggering positive anthropic influences on its sediment budget. The past-to-future sediment budget approach proposed herein provided a unified perspective on the evolution of the main drivers of coastal change and simultaneously offers foundations for adaptations strategies aiming at increasing sustainability of insular beaches.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

  • 文章类型: Journal Article
    植物中叶子颜色的可视化提供了对叶子中存在的一些化合物的直接了解。然而,许多无色的化合物也存在;它们的细胞分布不容易被光学识别。在这项研究中,我们通过电喷雾激光解吸电离(ELDI)评估了质谱成像(MSI)的适用性,以揭示代谢物的空间分布。ELDI-MSI是一个无矩阵,大气压电离方法,利用UV激光与通过电喷雾的补充电离耦合。我们特别应用了ELDI-MSI来确定半叶完全照亮或阴影生长的半叶中代谢物的空间分布。我们在28天的时间内每7天监测代谢物空间分布的动态变化,以响应光照的变化。在实验叶片的两半之间观察到了一种新的源-汇关系。此外,海葵叶呈现与类黄酮的差异积累相关的视觉上可识别的区域。因此,我们将不同光照和类黄酮的存在或不存在的影响与碳水化合物积累所揭示的代谢变化相关联,氨基酸,有机酸。结果表明,ELDI-MSI具有为多种植物代谢物提供空间信息的潜力,而样品制备很少。
    The visualization of foliage color in plants provides immediate insight into some of the compounds that exist in the leaf. However, many non-colored compounds are also present; their cellular distributions are not readily identifiable optically. In this study we evaluate the applicability of mass spectrometry imaging (MSI) via electrospray laser desorption ionization (ELDI) to reveal the spatial distribution of metabolites. ELDI-MSI is a matrix free, atmospheric pressure ionization method that utilizes a UV laser coupled with supplemental ionization by electrospray. We specifically applied ELDI-MSI to determine the spatial distribution of metabolites in Coleus Henna half leaves that were grown with half-sections either fully illuminated or shaded. We monitored dynamic changes in the spatial distribution of metabolites in response to the change of illumination every 7 days for a 28 day period. A novel source-sink relationship was observed between the 2 halves of the experimental leaf. Furthermore, Coleus Henna leaves present visually recognizable sectors associated with the differential accumulation of flavonoids. Thus, we correlated the effect of differential illumination and presence or absence of flavonoids with metabolic changes revealed by the accumulation of carbohydrates, amino acids, and organic acids. The results show the potential of ELDI-MSI to provide spatial information for a variety of plant metabolites with little sample preparation.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

       PDF(Pubmed)

  • 文章类型: Journal Article
    To understand the source-to-sink of pollutants in the Kelantan River estuary and the adjacent shelf area in Malaysia, a total of 42 surface sediment samples were collected in the Kelantan River-estuary-shelf system to analyze for grain size, total organic carbon (TOC) content, Al and heavy metals (Cr, Ni, Cu, Zn, Cd and Pb). The surficial sediments were mainly composed of clayey silt and the TOC content in sediments decreased from the river to the shelf. The surficial sediments experienced Pb pollution; Cr only showed a certain level of pollution in the coastal area of the estuary but not in other areas, and Ni, Cu, Zn, and Cd showed no pollution. The heavy metals mainly originated from natural weathering and erosion of rocks and soils in the catchment and enriched near the river mouth. Total organic carbon can promote the enrichment of heavy metals in sediments.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

公众号