POTENTIOMETRIC TITRATION OF CALCIUM IN SEAWATER   总被引：2，自引：0，他引：2  

谢式南  纪红  吴爱琴  陈国华 《中国海洋湖沼学报》1997,15(1):32-35

Atpasent,thestandardmethodfordetendningcalciuminseawateriscomPlexometrictitrationusingEGTA[ethyleneglycol-bis(2-adrinoethylether)-N,N,N',N'-tetraaceticacid]andGHAtelyoxal-bis(2-hydroxyanil)].ThisInethodwasfirStdeveopedbyTSunogaietal.(l968),sumrnarindbyKremling,andeditalinMethodsofSeawaterAnalySisbyGrasshoff(l983).AlthoughtheendpointreadingsinthismethodarenotquitCsharp,andrnaybeaffCCtedbyoveanstweather,withtheuseofcalctumISEasindicatingeledrode,SCEasreferenceeledrodeanddigitalvoltme…  相似文献   

水体悬浮颗粒物主要组分的萃取分离及重金属的分布特征   总被引：1，自引：0，他引：1  

沈秀娥  董德明  路永正  吕丽莎  花修艺 《吉林大学学报(地球科学版)》2007,37(4):797-803

为了考察悬浮颗粒物中主要组分对重金属的富集作用,采用选择性萃取法分离长春市伊通河和南湖悬浮颗粒物中的铁、锰氧化物,优化了萃取条件,测定了悬浮颗粒物中的铁、锰氧化物和有机质等组分中富集Cu,Pb和Zn的含量,分析了上述3种重金属在悬浮颗粒物主要组分中的分布特征。结果表明,0.006 mol/L NH2OH.HCl 0.01 mol/L HNO3萃取30 min可以单独萃取悬浮颗粒物中大部分的锰氧化物,0.8 mol/L Na2S2O4(pH=6.0)萃取40 min可以同时萃取铁、锰氧化物,而对非目的组分的影响较小;悬浮颗粒物对Cu、Pb、Zn重金属有明显的富集作用,其中Cu主要结合在悬浮颗粒物的有机质组分中,Pb主要富集在铁、锰氧化物中,锰氧化物和有机质对Zn的分布起主要的富集作用。  相似文献   

青藏高原放牧强度空间化方法与应用     

胡晓阳  王兆锋  张镱锂  宫殿清 《地理学报》2022,77(3):547-558

人类活动强度空间化是分析人类活动区域差异及其变化过程的基础,也是准确辨识土地变化驱动因素、合理调控人类活动的科学依据。当前人类活动强度研究多以数理方法对代用指标进行空间化,缺乏对人类活动机理过程的反映,也制约了人类活动强度空间异质性的展现。本文以青藏高原放牧活动为研究对象,在综合放牧喜好和草地管理策略的基础上,从放牧行为机理的角度,提出了区分放牧区与非放牧区的方法;以放牧密度衡量草地整体放牧压力,以放牧概率刻画放牧活动的空间差异,构建了区域放牧强度空间化模型。并以高原典型牧业县—泽库县为例,基于乡镇级牧业数据和自然地理基础信息进行了实证研究。结果表明：空间化结果较好反映了泽库县放牧强度的空间特征;直接指标的选取和客观的赋值方法提高了放牧强度空间化结果的准确性;比现有研究结果更能体现出县域内放牧强度的空间差异,且放牧强度变化过程与同期NDVI值变化具有较好的耦合性。本文为人类活动空间化方法研究提供了有益参考。  相似文献   

HYDROLOGY AND TRANSPORT OF MATERIAL IN THE SERMILIK AREA 1972     

BENT HASHOLT M.Sc. 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(1):30-39

Hasholt, B., 1976; Hydrology and transport of material in the Sermilik area 1972. Geografisk Tidsskrift 75: 30–39 København june 1976.

Investigations of water discharge and transport of material have been carried out in the area around the Mitdluagkat glacier in East Greenland. Precipitation and snow-melt were measured and compared with the discharge. The relationship between stage, discharge and concentration of suspended sediments were found, and the results were used to calculate hourly values of suspended sediment transport. In a few cases bed-load and dissolved load were measured at the same time as suspended load. The ratio between the transport components has been used to estimate the total load into the sea.  相似文献   

四川祁家河铅锌硫多金属矿选矿试验研究   总被引：1，自引：0，他引：1       下载免费PDF全文

石磊  赵华伦  杜新  雷力  邱允武 《地质找矿论丛》2012,27(1):125-129

对四川祁家河铅锌硫多金属矿采用优先浮选流程,实现了铅、锌、硫的有效分离回收,获得了的铅品位和回收率分别为55.50％和75.45％的铅精矿,锌的品位和回收率分别为50.58％和92.87％的锌精矿,硫的品位和回收率分别为47.22％和71.76％的硫精矿.  相似文献   

冬季南海北部海域微型浮游动物及其对浮游植物摄食压力研究   总被引：1，自引：0，他引：1  

郑丽平  相卫国  黄邦钦 《台湾海峡》2012,31(1):72-78

2009年1月在南海北部海域的5个站位,采用稀释法和显微分析技术研究了浮游植物生长率及微型浮游动物对浮游植物的摄食压力,同时测定了微型浮游动物的丰度及类群组成.结果表明:南海北部微型浮游动物类群主要以无壳纤毛虫为主,南海北部微型浮游动物类群细胞丰度为33～529个/dm3.南海北部浮游植物生长率为0.45～1.83 d-1,微型浮游动物摄食率为0.44～1.76 d-1,摄食压力占浮游植物现存量的42.6%～82.8%,占初级生产力的97.3%～225.1%.近岸区摄食压力比陆架区高,表明冬季南海近岸区微型浮游动物摄食能够有效的控制浮游植物的生长,而陆架区浮游植物生长率大于摄食率,浮游植物存在着现存量的积累,微型浮游动物并不能完全控制浮游植物的生长.  相似文献   

调剖技术在埕岛油田的应用及效果分析     

周明亮  刘芳  黄文  张春先  邓艳霞 《海洋地质译丛》2012,(1):74-78

基于埕岛油田的油藏特征及海上条件限制,依据PI决策理论,选用酚醛树脂交联体系冻胶,高黏的聚合物乳液为过顶替液,通过分轮次注入对4口井进行了深部堵水调剖。堵水调剖后,油藏水驱效果明显改善。通过对堵水调剖效果的分析研究,对深度调剖技术实施过程中堵剂的用量、冻胶凝固时间及施工轮次进行了总结和探索,对其他海上油田开展堵水调剖具有指导意义。  相似文献   

Social and ecological constraints on decision making by transhumant pastoralists: a case study from the Moroccan Atlas Mountains   总被引：1，自引：1，他引：0  

Zakia AKASBI  Jens OLDELAND  Jürgen DENGLER  Manfred FINCKH 《山地科学学报》2012,9(3):307-321

Transhumant pastoralism is an important activity in southern Morocco. Migration pattern of transhumant pastoralists can be affected by physical factors (e.g. droughts and diseases) or socioeconomic factors (e.g. schooling options for children and migration costs). We studied the spatio-temporal rangeland usage of the three tribes Ait Mgoun, Ait Zekri, and Ait Toumert in the south-central Atlas region with a two-fold approach. First, we tracked the migration movements of one representative transhumant herd using the Advanced Research and Global Observation Satellite (ARGOS) collars, which record coordinates from satellite signals. Second, we interviewed herders to obtain information about general grazing practices of the respective tribe and to gain more direct information on motivations underlying decisions. For each tribe we observed small-, medium- and large-scale movements. We found that the most important drivers of migration decisions were seasonal fodder availability and weather conditions in combination with herd-specific risk and cost assessment, as well as personal factors. In conclusion, general migration patterns vary in time, both between and within the tribes, but according to a regulatory framework. Moreover, it appears that both the customary rules and its flexible adaptation to physical constraints are generally beneficial in terms of conservation of the arid and semiarid rangeland resources.  相似文献   

Laboratory studies on zooplankton‐cyanobacteria interactions     

Winfried Lampert 《新西兰海洋与淡水研究杂志》2013,47(3):483-490

Laboratory studies on cyanobacteria‐zooplankton interactions have largely focused on the inadequacy of cyanobacteria as a food source. Some features of cyanobacteria can be regarded as anti‐herbivore defences. Large colonies of Aphanizomenon, Anabaena and Microcystis cannot be handled by zooplankton, but do not interfere seriously with the filtering process. Small colonies and filaments, however, may cause severe inhibition of the feeding process by mechanical interference. This reduces zooplankton growth, reproduction, and survival. Copepods, rotifers, and Bosmina are less affected by mechanical disturbance than cladocerans. If ingested, some cyanobacteria may be poorly digested or may not provide essential nutrients. Some cyanobacteria are reported to be toxic to zooplankton. Several strains of Microcystis produce an endotoxin, but the amount of toxin produced differs among strains and with the condition of Microcystis. Zooplankton encountering toxic cells cease feeding. Some evidence of an extra‐cellular herbivore deterrent was found for Anabaena. Thus, cyanobacteria may either be individually protected or may create an environment that is unfavourable for efficient grazers (e.g., Daphnia).  相似文献   

Hydrology of Okarito Lagoon and the inferred effects of selective logging in Okarito Forest     

J. M. Macpherson 《新西兰海洋与淡水研究杂志》2013,47(1):25-39

Okarito Lagoon (43° 11′S, 170° 14′E) is a small (20 km²) shore‐parallel, predominantly subtidal estuary, deepest near the landward end, and linked to the sea by two subtidal channels incised through shallow subtidal and intertidal flats which occupy the southern third of the lagoon. Tides at sea vary from 2.1m (spring) to 1.2 m (neap), but in the lagoon the tidal range is constant through the lunar cycle and varies from 0.80 m at the entrance to 0.17 m in the upper lagoon. Tidal water level and flow asymmetries in the subtidal channels are separated by a 1.7 h phase difference. Variations in the net discharge through the inlet result from changing flow cross‐sections rather than from variations in current velocities. Both the tidal‐averaged volume and the tidal compartment of the lagoon vary through the lunar cycle, from maxima at spring tides to minima at neap tides.

Freshwater inflows vary from less than 11 m³.s^‐1 to more than 750 m³.s^‐1. During storms, water level in the lagoon rises rapidly by 2–3 m, then declines to normal over several days. Three water masses, two with salinity and turbidity largely controlled by antecedent rainfall, normally occur in the lagoon. Suspended sediment concentrations in both freshwater inflows and lagoon waters are normally low but increase during floods. Most sediment is supplied by the Waitangi‐taona River or by erosion of tidal channel margins. The lagoon is floored with organic‐rich mud and sandy mud, deposited predominantly from suspension. Surface sediment is consistently muddier than subsurface sediment, probably reflecting an increase in the mud supply since diversion of the Waitangi‐taona River in 1967.

Comparisons of the estimated sediment yield and water inflow effects of the 1967 river diversion with short‐term observations during selective logging suggest that the effects of logging on sediment yield, water balance of the lagoon, and dissolved solids inputs will be small compared with changes caused by diversion of the Waitangi‐taona River.  相似文献