察尔汗盐湖卤水自然蒸发过程中Ca2+分布规律研究

卤水中钙离子的存在会对盐湖化工生产及其产品质量造成较大影响,研究钙离子在卤水蒸发过程中的分布规律具有重要意义。通过室外自然蒸发及盐田实地采样,研究了察尔汗盐湖盐田生产过程中钙离子分布变化规律。结果表明,在自然蒸发实验中卤水钙离子浓度随蒸发量的增加逐渐减少,在盐田生产现场采样结果显示钙离子浓度随卤水蒸发而增加,结合生产实际,推断外界钙离子补给是造成这种现象的主要原因。因此,避免车间含钙尾水混入,阻止盐田卤水和周边土壤可溶性钙盐间离子交换是有效降低卤水钙离子浓度的主要方法。     

南水北调东线工程通水后东平湖水质评价

为了解南水北调东线工程全线通水后东平湖水质状况,于2015年6月（枯水期）采集了东平湖4个地表水样品和7个地下水样品,测定了其中As、Cd、Cr、Cu、F、Hg、Mn和Pb等8种元素的含量,采用综合污染指数法、综合水质评分法和健康风险评价模型评价了其水环境质量和健康风险,结果表明：地表水中重金属浓度多数满足地表水环境质量标准I类,其中Hg污染相对较重,地下水中重金属浓度多数满足地下水质量标准III类及以上,其中F和Mn污染相对较重;4个地表水采样点综合污染指数均小于1,表明其水质优良,地下水中3个采样点的综合水质评分小于2.5,水质良好,4个采样点的综合水质评分大于4.25,水质较差;地表水的平均健康风险为9.18×10-5a-1,地下水的平均健康风险为8.16×10-5a-1,均为III级中风险。     

Evolution of the trophic state of Lake Annecy (eastern France) since the last glaciation as indicated by iron, manganese and phosphorus speciation

Lake Annecy sediments have been studied to provide an insight into the evolution of the lake trophic state in response to climate changes during the Holocene. Determination of the concentration of carbonate, Fe, Mn, and different forms of P in conjunction with total sediment fluxes derived from ¹⁴C ages allows an estimation of yearly fluxes of these sediment components. High fluxes of endogenic carbonate occur during the early to middle Holocene. Non apatitic inorganic phosphorus flux is variable but shows some higher-than-present values during this period. These observations are interpreted as being a result of enhanced productivity by favourable conditions for phytoplankton development. In addition, the low Mn/Fe ratio of the redox-sensitive forms of these elements recorded during this period suggests low oxygen concentrations in the bottom waters. Therefore it appears that the lake may have undergone oxygen depletion in the bottom water during the warmer-than-present periods, due to increased productivity and subsequent oxygen consumption from the decay of organic matter. With future climate changes, this suggests that lake water quality may likely degrade under global warming.     

Reconstructing nutrient histories in the Norfolk Broads, UK: implications for the role of diatom-total phosphorus transfer functions in shallow lake management

The fossil diatom records preserved in radiometrically dated sediment cores from four shallow lakes in the Norfolk Broads, UK (Barton Broad, Rollesby Broad, Wroxham Broad and Upton Broad) were analysed. A weighted-averaging partial least squares (WA-PLS) diatom-total phosphorus (TP) transfer function, based on a training set of 152 mostly shallow (maximum depth < 3 m) lakes in northwest Europe, was applied to the full diatom dataset for each core to reconstruct the past TP concentrations of the lakes. Owing to the dominance of non-planktonic Staurosira, Pseudostaurosira and Staurosirella spp. (formerly classified in the genus Fragilaria) throughout the diatom records, the quantitative diatom inferred TP (DI-TP) concentrations did not adequately reflect the changes that occurred in the lakes as indicated by shifts in the other diatom taxa, or as reported in the literature. This was most apparent at Barton Broad and Rollesby Broad, where there was a marked increase in the importance of planktonic taxa associated with highly nutrient-rich waters but no increase in DI-TP. The modern and fossil data were thus square-root transformed to downweight the dominant taxa and the new transfer function was applied to the cores. An improvement was seen only in the reconstruction for Barton Broad. Finally, the Staurosira, Pseudostaurosira and Staurosirella spp. were removed from the modern and fossil diatom data, and the transfer function was re-applied. The trends in DI-TP became less clear, particularly for Upton Broad and Barton Broad, owing to a paucity of data for calibration once these taxa were deleted from the counts data. The problems associated with reconstructing trophic status and determining TP targets for restoration from fossil diatom assemblages in these systems are discussed.     

Preliminary reconstruction of sediment-source linkages for the past 6000 yr at the Petit Lac d'Annecy, France, based on mineral magnetic data

An 8 m core from the central plain of the Petit Lac d'Annecy, France, two floodplain cores, river bedload sediments and several hundred soil samples from the catchment have been studied using magnetic techniques. The soils, mainly developed on limestones and local glacial tills, show widespread magnetic enhancement with higher ferrimagnetic concentrations and contents of SP grains than found in the lake sediments. Some soils show significant concentrations of canted antiferromagnetic minerals (mainly haematite). Using magnetic quotient parameters the surface soils are classified into four mineralogical types. The lake and floodplain sediment properties over the past 6000 yrs can largely be explained by the erosion and deposition of these sources, with a smaller superimposed biogenic (magnetosomes) signal. Derived sediment-source linkages allow the construction of several hypotheses about geomorphological changes in the catchment system: (i) the long-term erosion of high altitude unweathered substrates has gradually increased towards the present day; (ii) the erosion of high altitude soils has increased within the last 1000 yrs, possibly during the period of the 'Little Ice Age'; (iii) shifts towards an increased erosion of surface lowland soil occurred ~2000 and 1000 yrs ago and may be linked to an accelerated accretion of floodplain overbank deposits; (iv) there has been a significant storage of surface soil within floodplains, which leads to an underestimation of the importance of soil erosion in the lake sediment records; (v) the sediment transported by high magnitude, low frequency flood events has shifted in source from high altitude soils before ~1000 cal. yr BP to lowland and mid-altitude free draining soils after ~1000 cal. yr BP.     

南极长城站地区西湖底沉积物化学元素分布规律及其环境意义

利用南极长城站地区西湖底沉积物的化学元素背景值，对西湖底沉积物元素的时序分布规律及其指示的环境意义作了较细致的研究。研究表明，湖底沉积物元素的时序变化规律与站区自然环境变化密切相关。尽管元素的时序变化滞后于自然环境的波动，但对研究长城站地区自然环境演变仍具有一定的指示意义。尤其是Ｓ元素的异常变化，可能揭示出长城站地区两次规模较大的火山活动。     

洞庭湖地区地球化学土壤质量分区及评价

该文根据营养元素的含量，对洞庭湖地区的土壤质量进行了优、劣分区。在优势区可以少施或免施钙镁磷肥，在劣势区应少施有机肥和磷肥，多施氮、钾肥及多元素复合肥。     

Sediment-chemistry response to land-use change and pollutant loading in a hypertrophic lake, southern Sweden

Responses to recent land-use changes and pollutant loading in the sediment of a hypertrophic lake in southern Sweden were studied by comparison of geochemical, pollen and magnetic records with historical land-use data. A chronology was constructed for the last two centuries by correlating changes in the pollen diagram to major events in the land-use history. Sediment accumulation was low (mean c. 0.2 g cm^-2 yr^-1) prior to 1800 AD, when less than 25% of the catchment was arable land. Reorganization of the agrarian system during the 19th century increased the annually tilled area by 300%, which accelerated soil erosion and substantially increased the accumulation of allochtonous matter in the lake. Since the turn of the century 90% of the catchment has been ploughed every year. The deposition of clastic matter in the lake has, however, decreased due to a gradual rerouting of the drainage system, which has reduced the effective catchment area by c. 85%.Authigenic vivianite (Fe3(PO4)2.8H2O) is a major P phase in the preindustrial non-sulphidic sediments, which suggests that the sediments at that time served as a fairly efficient sink for P. The arable expansion, increased manuring and, eventually, the introduction of artificial fertilizers during the 19th century led to a massive influx of nutrients, which elevated primary production in the lake. Subsequent development of bottom water anoxia around 1900, in combination with an additional pollutant burden of sulphate within the lake basin, led to major alterations of the biogeochemical cycles. The most critical change in the post-1900 sediments involved the cycling of Fe and P. The linkage between the lacustrine P and Fe cycles can explain that FeS formation was paralleled by a release of P from the sedimentary pool. This supply of P to the lake basin must have supplemented the nutrient supply by modern agriculture and contributed to recent hypertrophication. The bacterial sulphate reduction also affected the generation of alkalinity which supported a significant calcite precipitation in the post-1900 sediments.S is enriched 10-fold in the post-1900 sediments compared to preindustrial values. Along with the rise in S, soot particles derived from fossil fuel combustion appear in the sediments for the first time. Therefore, Bussj¨osj¨on is thought to be a good example of how a well-buffered, highly productive lake may respond to the pollution by sulphur from acid rain.     

Differential sedimentation versus coring artifacts: a comparison of two widely used piston-coring methods

In order to compare two widely used piston-coring techniques, parallel cores were taken with both a Kullenberg and a Livingstone corer in the deepest part of Soppensee (25 m), a small eutrophic Swiss lake containing varved sediments. The cores were taken within a horizontal distance of 3 m and yield comparable stratigraphic records. Differences in millimetre-scale microstructure are attributed to primary sedimentation processes at the water/sediment interface. Sediment thin-sections, as well as sediment x-radiograph investigations, reveal no difference in microstructure that could unequivocally be attributed to one of the coring methods used. The differences in deposition are therefore thought to reflect the inherent variability of lacustrine sedimentation in Soppensee.Major differences in overall core recovery do occur, however, in organic-rich, highly porous sediments. These variations are primarily attributed to differential gas expansion. Actual sediment-accumulation rates can therefore only be correctly estimated if the sedimentary record can be constrained within a high-resolution temporal framework, e.g. by annual laminations.     

高邮湖的形成和发展

高邮湖地区古为古潟湖浅洼平原,局部浅洼地段有小湖泊。金明昌五年(1194年)黄河夺淮以后,由于治河者多采用在黄河北岸筑堤南岸分流以保漕为主的政策,把大量黄水引泻到淮河流域的广大地区,使高邮湖诸小湖的湖面不断扩大,曾一度发展到五荡十二湖,到了明代后期,才基本上汇为一湖。