The accumulation of radiocesium in coarse marine sediment: effects of mineralogy and organic matter

The controlling factors affecting the accumulation of (137)Cs in marine sediment have not been investigated in detail, especially in coarse grained sediment. Eighty eight coarse marine sediment samples near Wuljin, Korea, were characterized by quantitative X-ray-diffraction (XRD), gamma-ray, and total organic carbon (TOC) analysis. Those factors were then compared. The grain size was in the range of -0.48 to 3.6Mdphi corresponding to sand grains. TOC content was in the range of 0.06-1.75%, and the concentration of (137)Cs was 相似文献   

Mercury speciation in sediments at a municipal sewage sludge marine disposal site

Mercury speciation was performed in excess activated sewage sludge (ASS) and in marine sediments collected at the AAS disposal site off the Mediterranean coast of Israel in order to characterize the spatial and vertical distribution of different mercury species and assess their environmental impact. Total Hg (HgT) concentrations ranged between 0.19 and 1003ng/g at the polluted stations and 5.7 and 72.8ng/g at the background station, while the average concentration in ASS was 1181+/-273ng/g. Only at the polluted stations did HgT concentrations decrease exponentially with sediment depth, reaching background values at 16-20cm, the vertical distribution resulting from mixing of natural sediment with ASS solids and bioturbation by large populations of polycheates. Average Methyl Hg (MeHg) concentration in ASS was 39.7+/-7.1ng/g, ca. 3% of the HgT concentration, while the background concentrations ranged between 0.1 and 0.61ng/g. MeHg concentrations in surficial polluted sediments were 0.7-5.9ng/g (ca. 0.5% of the HgT) and decreased vertically, similar to HgT. A positive correlation between MeHg and Hg only at the polluted stations, higher MeHg concentrations at the surface of the sediment and not below the redoxline, and no seasonality in the concentrations suggest that the MeHg originated from the ASS and not from in situ methylation. By doing selective extractions, we found that ca. 80% of the total Hg in ASS and polluted sediments was strongly bound to amorphous organo-sulfur and to inorganic sulfide species that are not bioavailable. The fractions with potential bioaccessible Hg had maximal concentrations in the range in which biotic effects should be expected. Therefore, although no bioaccumulation was found in the biota in the area, the concentration in the polluted sediments are not negligible and should be carefully monitored.     

'Green' enclosure of ocean space--déjà vu?

The first wave of unilaterally declared environmental protection zones (starting with Canada's Arctic Waters Pollution Prevention Act of 1970) may have been halted by the 1982 UN Convention on the Law of the Sea. Yet, a second wave now seems to be gaining momentum: the French 'ecological protection zone in the Mediterranean' of April 2003 (promptly emulated by Croatia, Slovenia, and Italy), the British 'environment (protection and preservation) zone' around the Chagos Archipelago of September 2003, and the US 'marine national monument' around the Northwestern Hawaiian Islands of June 2006, all claiming new environmental regulatory powers in sea areas way beyond territorial waters. This viewpoint article questions the unilateral legitimation of those claims, and postulates a trusteeship ethos and fiduciary accountability for ocean governance in these areas.     

面向海运统计的AIS大数据挖掘分析研究

为解决传统海运产业统计方法数据质量不高、时效性差、统计产品陈旧短缺、公信力不足等的问题,提出基于AIS大数据挖掘分析开展海运统计的方法.详细阐述了基于AIS大数据的海运统计分析技术路线、大数据平台技术架构,以及电子围栏分析、航行事件分析、航次分析和统计指标生成等关键模型算法.以2019年3月至5月全球大宗货品船舶的AIS数据应用为例表明,该方法可提供港口、海上通道和大宗货品三方面的海运大数据统计指标,为实现海运即时化、准确化、精细化的统计分析与展现提供了新思路.     

山东省海洋空间开发保护现状、问题及对策

海洋是国民经济发展和社会进步的重要空间载体,海洋国土空间开发与保护对于实现可持续的经济增长、改善全球气候环境和提升人民生活福祉具有重大战略意义。山东省海域使用类型基本齐全,但开发利用结构规模不均衡,渔业用海比重较大,不合理的开发利用给海岸带和近海生态环境带来巨大威胁,严重制约了海洋经济的健康发展。文章根据山东省海域使用调查数据,综合分析了山东省海洋空间使用现状的特点以及存在的自然岸线保有压力增大、海洋空间开发利用科学性不足、近岸海域生态系统及服务功能受损较重、海洋污染造成的环境风险不容忽视、现代海洋产业体系不够完善、陆海统筹机制不健全等主要问题,在此基础上,从海洋空间资源、陆海统筹污染防治体系、现代海洋产业体系等角度提出了优化山东省海洋国土空间开发保护的相关对策建议。     

一株岩生真菌对白云岩中稀土元素溶出、迁移和富集影响的研究

选用一株从碳酸盐岩表面分离的真菌,研究了实验条件下岩生真菌对白云岩中稀土元素的溶出、迁移和富集作用过程。通过分析不同培养时间真菌培养液上清液及菌丝体稀土元素浓度和组成特征,研究了真菌生命活动对稀土元素行为的影响,探讨了微生物影响稀土元素行为的机制。结果表明,该株真菌对白云岩中稀土元素的溶出、迁移和富集有一定的作用,真菌的活动可以提高稀土元素溶出量,使Ce相对活化,对Eu则有抑制作用,培养液上清液和真菌菌丝体均具富Ce贫Eu的特征;真菌生长产生的酸性环境、氧化还原作用、代谢产物的络合作用,以及真菌菌丝体的直接吸收和吸附作用,是该株真菌影响稀土元素行为的主要机制。     

莺-琼盆地海相烃源岩特征及高温高压环境有机质热演化

莺歌海盆地与琼东南盆地存在渐新统海岸平原-半封闭浅海相和中新统浅海相两套海相烃源岩。其中,渐新统烃源岩发育于琼东南盆地早第三纪半地堑,存在海岸平原和半封闭浅海两类烃源岩组合。海岸平原含煤烃源岩有机质丰度高,富含陆源有机质,具有很好的生气潜力;半封闭浅海相烃源岩TOC含量总体低于1.0%,但其规模大且存在TOC1.5%的较高丰度段,故亦具有较大的生气能力。中新统海相烃源岩主要分布于莺歌海盆地裂后热沉降形成的中央坳陷,其有机质丰度横向变化比较大,位于中央坳陷带的烃源岩有机质丰度较高,TOC大多在0.40%～2.97%之间,有机质以气型干酪根为主。盆地的高地温为有机质向天然气转化提供了有利的条件,尤其是热流体活动使浅层有机质超前熟化,但地层超压对有机质热演化也有一定的抑制作用。盆地模拟结果显示,莺-琼盆地主要凹陷烃源岩大量生气时间较晚,与圈闭形成期的时空配置好,有利于成藏。     

Sedimentology,palaeoecology and geochronology of Marine Isotope Stage 5 deposits on the Shetland Islands,Scotland

New stratigraphical, palynological and dating evidence is presented for pre‐Late Devensian/Weichselian sediments at Fugla Ness and Sel Ayre, Shetland. The Fugla Ness Peat rests on till and formed during an interglacial that saw the development of maritime heaths, with scattered trees and shrubs, including Pinus and possibly Ilex. A decline into stadial conditions is marked by overlying periglacial breccia and till. The Sel Ayre Organic Sands and Gravels lie between periglacial breccias and beneath till and appear to record a changing interstadial environment in which trees were absent and the vegetation comprised largely heaths, with Bruckenthalia, and grasslands. The Fugla Ness Peat is dated to 110+40/?35 ka by uranium series disequilibrium, suggesting that it formed during the Ipswichian/Eemian Interglacial (Marine Isotope Substage 5e). Luminescence ages of ca. 98–105 ka on intercalated sands within the Sel Ayre Organic Sands and Gravels place these deposits in Marine Isotope Substage 5c (Brørup Interstadial). The two sites provide the first detailed record of Marine Isotope Stage 5 environments on Shetland. Copyright © 2002 John Wiley & Sons, Ltd.     

海洋中溶解甲烷的原位检测技术研究进展

海水中溶解甲烷气体不但对全球变暖和海洋环境变化有着重要影响,而且也是发现渗漏型天然气水合物赋存区的依据之一,海水溶解甲烷原位监测的新技术和新方法是获取海水甲烷通量变化过程的主要手段。原位甲烷传感器具有原位、实时、便于多时空尺度定量观测等特点,在海洋环境变化和全球气候变化研究,以及海底资源开发利用中具有广泛的应用前景。介...     

云南勐海关双铁矿矿床成因

关双铁矿位于大南婆—惠民—西定金多金属矿富集区。矿床成因与澜沧惠民铁矿类似,属海相火山沉积变质型。