共查询到20条相似文献，搜索用时 314 毫秒
1.
海洋塑料作为一类具有潜在生态风险的污染物,已经引起了研究人员的重点关注。大到数米的塑料垃圾,小到微米级的微塑料,塑料污染物以各种形式在海洋环境中广泛存在。因能长期以固体形式赋存于海水和沉积物中,塑料污染物比溶解性污染物更难在海洋介质中均匀分散;但近年来,各项调查活动却在远离塑料来源的大洋、极地和深海中均发现了塑料污染物,这显然与塑料在海洋环境中的迁移息息相关。一方面,海洋中塑料污染物的分布和迁移受到塑料自身性质以及多种环境因素的影响。因此,针对海洋塑料污染物设计监测方案时,有必要通过对这些因素的研判,规范和优化采样方案,有效提高采样代表性。另一方面,了解海洋塑料污染物迁移和归趋的影响因素,也是预测塑料污染物蓄积和富集的海域或层次,推断其在海洋生境中的暴露情况,进而预测其潜在风险的必要前提。本文归纳了海洋塑料污染物迁移规律的相关研究,分析了影响海洋中塑料污染物水平和垂直分布的因素,总结并列举了在海洋水体和沉积物介质中塑料污染物监测活动的常用采样方法,分析了塑料污染物监测活动方案的制订依据和注意事项。 相似文献
2.
尽管水是污染物潜在载体，但是土壤却既可以是污染物载体也可以阻碍污染物的运移。静态的土壤基质减慢了地下水的运动，使污染物吸附在固体表面之上，使其运动减缓或停止下来。另一方面，由于风、水流和建设设备携带，土壤也能够运移。运动的土壤一就象流水， 相似文献
3.
图们江是我国重要的国际性河流之一,受中国、朝鲜、俄罗斯三国政策、经济、文化等因素影响,三国的湿地景观截然不同。本文以我国国产高分辨率卫星GF-1和GF-2影像为数据源,通过对图们江口湿地的实地踏勘,建立了图们江口湿地遥感分类体系,包括湖泊、河流、沼泽、滩涂、坑塘、水田和水库共7类。采用目视解译方法,提取了图们江口湿地信息,对图们江口湿地现状和中、朝、俄湿地差异进行了分析。利用Fragstats景观分析软件,选取了斑块数(NP)、最大斑块指数(LPI)、斑块平均面积(MPS)、加权平均形状指数(SHAPE)、加权平均分形维数(FRAC)、香农多样性指数(SHDI)和香农均匀性指数(SHEI)等几个景观格局指数分析了图们江口湿地景观格局特征。结果表明:(1)研究区湿地总面积为39 503.38 hm2,以沼泽和湖泊为主,呈现近日本海聚集分布格局。(2)俄罗斯湿地面积占各国研究区湿地总面积比例最大,朝鲜次之,中国最小;朝鲜湿地开发程度最高,湿地破坏较严重。(3)朝鲜湿地破碎程度在三国中最重,中国次之;朝鲜因水田开发较严重,景观规则度最高;中国湿地多样性较其他两国丰富。 相似文献
4.
图们江是流经中国、朝鲜、俄罗斯3国的河流,3个国家不同的经济发展水平导致图们江口地区3国的土地利用程度也不尽相同。文章以我国国产高分辨率卫星影像GF-1和GF-2为数据源,采用目视解译方法,提取了图们江口土地利用/覆盖信息,对图们江口土地利用/覆盖现状及其中、朝、俄对比情况进行了分析。研究结果表明:(1)图们江口地区的主要土地利用/覆盖类型为林地、草地、耕地、水域、沼泽等,其中林地主要分布在山地丘陵地带;草地在俄罗斯的平原、丘陵地区分布较广;耕地主要分布在中国和朝鲜地区;沼泽在俄罗斯境内分布较广。(2)中国研究区内,林地面积最大,草地、耕地、水域面积较大,集中分布在平原地带;朝鲜研究区内,林地面积最大;俄罗斯研究区内,土地结构的主体为林地、草地、水域,与中国和朝鲜相比,结构比较均匀,自然景观保护最好。(3)朝鲜区域土地开发最为剧烈;俄罗斯区域土地开发强度最低;中国区域土地开发强度适中。 相似文献
5.
辽东湾氮、磷和COD环境容量的数值计算 总被引：12，自引：1，他引：12
一个原始方程海洋环流模式(POM)被用来模拟辽东湾环境动力场,同时用有限容积方法对描述氮、磷、COD等污染物输运过程的对流扩散方程进行离散,提高了计算精度和效率。通过对仙人岛海域四个采样点的实测浓度和相应点上的计算浓度的比较分析,并结合试验数据确立了适合辽东湾污染物浓度研究的降解系数;在此基础上进一步对各种污染物进行为期一年投放的数值实验,初步估算了各种污染物在辽东湾的保有容量、经过开边界的交换率以及非保守过程(磷、COD)的削减率。 相似文献
6.
排海污水处理直接关系到近海的污染,而氮、磷及有机污染物是近海的重要污染物。文章综述了几种对氮、磷及有机污染物处理的新工艺技术和各工艺的进展状况并提出应尽快推广应用。 相似文献
7.
用采自珠江口咸淡水交汇区河段的水和沉积物进行自净试验。试验池内介质由某一段面的水和相应断面的沉积物组成。试验按加入和未加入污染物、流动状态和静止状态的条件组合进行。从试验获得的数据看，在加入污染物的试验池水中，ＣＯＤＭｎ、油类和砷含量变化有如下规律：以石油含量降解最为迅速，在１—３ｄ内可降至未加入水平；其次是砷，自净速度与盐度有关，其含量降解５０％时在低盐度水试验池中为６ｈ，在盐度较高水中约需２ｄ，水中ＣＯＤＭｎ、油类和砷的自净作用在试验开始后的第一天里进行最快；相同介质的试验池比较，动态条件比静态条件更有利于水中污染物的自净。此外，还应用试验结果对珠江口咸淡水交汇区水中污染物自净效应作了初步的估算。 相似文献
8.
在穆尔曼斯克区西南部低山-丘陵地带，伊曼德洛夫凹陷西界附近，约纳河盆地中分布着北西-南东向延伸的科达湖。湖泊的长度为3．5km，宽度达0．4km。凹陷基本上被水-冰川砂砾沉积层充填，在其上几乎到处（包括现代湖床范围之外）分布着硅藻层（50％以上由硅藻硬皮组成的岩石）。在岩层的下部可划分出20cm的海泥夹层，即所谓的硅藻腐泥。硅藻的最大厚度达12～13m，存在于湖泊广阔和浅水的西北部。靠近岸边，岩层中的水被排干， 相似文献
9.
10.
环境中的污染物，极少单一存在，往往是多种并存。因此，它们对生物的影响是综合性的，可能产生拮抗(Antagonism)或协同作用(Synergism)。然而，以实验的方法研究多种重金属对海洋动物的效应的报道目前还不多见。已有的多为单种元素的实验研究，如Cunningham和Tripp，对汞在美洲牡蛎体内的积累、排出以及用同位素标记其在组织中的分布做了不少工作； Eisler等做了镉对海洋动物影响的研究；Phillipst近几年来做了监测重金属污染物的生物指标种的探讨。
毛蚶Arca (Anadara) subcrenata Lischke，在我国沿海均有分布，大量产于渤海，是沿海地区的重要食用贝类。作者以毛蚶为实验材料，探讨镉、铜、铅、镍、铬等五种混合的重金属在其体内的积累、排出和在器官组织中的分布，以及盐度变化对其积累的影响。这对于了解重金属对海洋生物的影响，进行环境质量的综合评价是很必要的，尤其在环境条件较为复杂的河口和海湾区域更具有重要意义。 相似文献
11.
Lars-Göran Danielsson 《Marine Chemistry》1980,8(3):199-215
Results of trace-metal analyses of water samples obtained during a cruise with the Soviet R.V. “Akademik Kurchatov” in the Indian Ocean are presented. The determinations were performed on board with atomic absorption spectrophotometry after a two-stage dithiocarbamate—Freon extraction procedure. Trace-metal concentrations found are in the same range as those found recently for similar open-ocean areas by other workers. The values for lead and zinc are probably high due to contamination. Vertical profiles indicate biogenic processes as controlling factors for the increase of cadmium, copper and nickel concentrations with depth. Iron shows an irregular depth distribution as a result of large random variations in concentration. 相似文献
12.
I. D. Marsden 《新西兰海洋与淡水研究杂志》2013,47(2):359-370
Paphies donacina (Spengler, 1793) populations were surveyed at 11 low tide sites on surf beaches along Pegasus Bay, Canterbury, New Zealand, during summer 1998. Random sampling was not feasible. At the non‐random sites chosen the average number of tuatua per 5 m of shoreline ranged between 0.1 and 62. Total wet weight biomass m‐2 was highest at the southern sites in the Bay. There were site‐related differences in length frequency distributions of tuatua populations. Northern populations included a wide length range and southern populations were dominated by larger bivalves. Average shell length increased significantly with distance south, being close to 40 mm at Waikuku and 80 mm at Taylors Mistake. The shell length: width and weight relationships were similar for tuatua collected over the whole geographic range. Average dry weight condition index varied significantly between sites (ANOVA F= 23.3, d.f. = 10, 329) depending on the length distribution of the contributing population. Where populations included a wide length range the condition index was positively correlated with shell length but in populations dominated by larger bivalves there was either no relationship or a negative relationship with shell length. Juvenile tuatua were found at average densities between 81 and 1200 m‐2 at all sites except Taylors Mistake. The mean length of recruits ranged from 2.2 to 3.1 mm and shell length was independent of both juvenile and adult density. These results are discussed in relation to the environmental and other factors thought to influence population structure and recruitment of tuatua in Pegasus Bay. 相似文献
13.
Tautog, Tautoga onitis, is an abundant species of fish in estuaries of the northeastern United States. Planktonic tautog larvae are abundant in summer in these estuaries, but there is little information on rates of growth of tautog larvae feeding on natural assemblages of food in the plankton. We examined abundance and growth of larval tautog and environmental factors during weekly sampling at three sites along a nearshore‐to‐offshore transect in Buzzards Bay, Massachusetts, USA during summer 1994. This is the first study of a robust sample size (336 larvae) to estimate growth rates of field‐caught planktonic tautog larvae feeding on natural diets, using the otolith daily‐growth‐increment method. The study was over the entire summer period when tautog larvae were in the plankton. The sampling sites contrasted in several environmental variables including temperature, dissolved oxygen (DO), and chlorophyll a concentration. There was a temporal progression in the abundance of tautog larvae over the summer, in relation to location and temperature. Tautog larvae were first present nearshore, with a pronounced peak in abundance occurring at the nearshore sites during the last 2 weeks in June. Larvae were absent at this time further offshore. From late June through August, larval abundance progressively decreased nearshore, but increased offshore although never approaching the abundance levels observed at the nearshore sites. The distribution and abundance of tautog larvae appeared to be related to a nearshore‐to‐offshore seasonal warming trend and a nearshore decrease in DO. Otoliths from 336 larvae ranging from 2.3 to 7.7 mm standard length had otolith increment counts ranging from 0 to 19 increments. Growth of larval tautog was estimated at 0.23 mm·day?1, and length of larvae prior to first increment formation was estimated at 2.8 mm indicating that first increment formation occurs 3–4 days after hatching at 2.2 mm. Despite spatial and temporal differences in environmental factors, there were no significant differences in growth rates at any of three given sites over time, or between sites. Because larval presence only occurred at a narrow range of temperature (17–23.5 °C) and DO (6.5–9.3 mg·l?1), in situ differences in growth did not appear to be because of differences in larval distribution and abundance patterns relative to these parameters. 相似文献
14.
A method for the determination by atomic absorption spectrophotometry of six major inorganic components of the organic particulate matter in seawater is described. Particles were formed by shaking aliquots of filtered seawater. The yield of aggregates varied greatly in replicate samples. The major factors in the variability of the analyses are the high and variable filter blank values for the elements of interest. 相似文献
15.
Klaus Kremling 《Marine Chemistry》1983,13(2):87-108
In June 1981, dissolved Zn, Cd, Cu, Ni, Co, Fe, and Mn were determined from two detailed profiles in anoxic Baltic waters (with extra data for Fe and Mn from August 1979). Dramatic changes across the O2H2S interface occur in the abundances of Cu, Co, Fe, and Mn (by factors of ?100). The concentrations of Zn, Cd, and Ni at the redox front decrease by factors between 3 to 5.Equilibrium calculations are presented for varying concentrations of hydrogen sulfide and compared with the field data. The study strongly supports the assumption that the solubility of Zn, Cd, Cu, and Ni is greatly enhanced and controlled by the formation of bisulfide and(or) polysulfide complexes. Differences between predicted and measured concentrations of these elements are mainly evident at lower ΣH2S concentrations.Cobalt proved to be very mobile in anoxic regions, and the results indicate that the concentrations are limited by CoS precipitation. The iron (Fe2+) and manganese (Mn2+) distribution in sulfide-containing waters is controlled by total flux from sediment-water interfaces rather than by equilibrium concentrations of their solid phases (FeS and MnCO3). The concentrations of these metals are therefore expected to increase with prolonged stagnation periods in the basin. 相似文献
16.
P.N. Froelich L.W. Kaul J.T. Byrd M.O. Andreae K.K. Roe 《Estuarine, Coastal and Shelf Science》1985,20(3):239-264
Concentrations of dissolved nutrients (NO3, PO4, Si), germanium species, arsenic species, tin, barium, dimethylsulfide and related parameters were measured along the salinity gradient in Charlotte Harbor. Phosphate enrichment from the phosphate industry on the Peace River promotes a productive diatom bloom near the river mouth where NO3 and Si are completely consumed. Inorganic germanium is completely depleted in this bloom by uptake into biogenic opal. The ratio taken up by diatoms is about 0·7 × 10?6, the same as that provided by the river flux, confirming that siliceous organisms incorporate germanium as an accidental trace replacement for silica. Monomethylgermanium and dimethylgermanium concentrations are undetectable in the Peace River, and increase linearly with increasing salinity to the seawater end of the bay, suggesting that these organogermanium species behave conservatively in estuaries, and are neither produced nor consumed during estuarine biogenic opal formation or dissolution. Inorganic arsenic displays slight removal in the bloom. Monomethylarsenic is produced both in the bloom and in mid-estuary, while dimethylarsenic is conservative in the bloom but produced in mid-estuary. The total production of methylarsenicals within the bay approximately balances the removal of inorganic arsenic, suggesting that most biological arsenic uptake in the estuary is biomethylated and released to the water column. Dimethylsulfide increases with increasing salinity in the estuary and shows evidence of removal, probably both by degassing and by microbial consumption. An input of DMS is observed in the central estuary. The behavior of total dissolvable tin shows no biological activity in the bloom or in mid-estuary, but does display a low-salinity input signal that parallels dissolved organic material, perhaps suggesting an association between tin and DOM. Barium displays dramatic input behavior at mid-salinities, probably due to slow release from clays deposited in the harbor after catastrophic phosphate slime spills into the Peace River. 相似文献
17.
18.
《Marine Policy》2015
Scholars and fishermen alike view the privatization of fishing rights as a fundamental driver of social change in fishing communities. This article presents the results of a mixed-methods ethnographic study in Kodiak, Alaska, exploring how fisheries privatization processes remake fishery systems. Findings from this study suggest that a diverse range of fishery participants share core values about the social dimensions of fishery systems. Support or opposition to past privatization processes tended to be articulated in reference to how these core values (e.g., hard work, opportunity, and fairness) were perceived to have been strengthened or eroded by such processes. Data from this study suggest that while still widespread in the Kodiak fishing community, core social values in fishing may be changing as a result of privatization processes. Although ethnographic and survey data showed a range of perspectives on the effects of privatization on fishing and the Kodiak community, study participants tended to talk about privatization as a significant change that had divisive, negative impacts in the community. Crew members and the next generation of fishermen were identified as disproportionately affected by privatization processes. Ethnographic data detail important shifts in the power, status, and livelihoods of crew members. Nearly all Kodiak fishery participants interviewed expressed concern about the future of fisheries access in the community for the next generation, in large part because of the substantial financial barriers to entry generated by privatization of fisheries access. Many discussed the need for more entry-level opportunities necessary for access in all fisheries. 相似文献
19.
Mercury, cadmium, arsenic, and antimony were analyzed in cores sampled on the Azores-Iceland Ridge. High values of 780 g · kg–1 for Hg, 1.7 g · g–1 for Cd, 87 g · g–1 for As, and 8.1 g · g–1 for Sb occur in the rift valley and transform faults. These enrichments, strictly linked to the ridge, could not have an allochtonous origin. A local hydrogenous flux may explain this phenomenon. These metallic enrichments may be connected to a hydrothermal activity extended between 43° N and 47° N. 相似文献
20.
Izvestiya, Atmospheric and Oceanic Physics - Data on the relative contribution of the Ox, HOx, NOx, ClOx, BrOx, and IOx catalytic cycles to atmospheric ozone destruction are given for June and... 相似文献