静心聆听·感悟——音乐欣赏课理想方式之刍议

静心聆听·感悟是音乐欣赏的理想方式。音乐欣赏的过程应促使学生在聆听中敏锐地感受音乐和感悟意义而学会音乐审美,以美育人。

PH_3 monitoring in Arctic and Dalian bay areas

In this paper, we use pre-column 2 times low-temperature cryo-trap enrichment--gas chromatography（GC） /nitrogen and phosphorus detector（NPD）to detect and analyze phosphine in Arctic pole area for the first time. The results show phosphine exists in all of the samples in Arctic pole biosphere and phosphine concentration in Arctic atmosphere is between 18.54- 132.18 ng/m^3, almost the same as that in Antarctic atmosphere; phosphine concentration in Dalian bay sea surface sediments is between 116. 8- 554.3 ng/kg, almost the same as that reported in Jiao-zhou bay. Our research of phosphine will shed new light on the mechanisms showing how the phosphorus supplement influences the biogeochemical cycle and global warming.

Seasonal Patterns of Nitrogen and Phosphorus in the Litter and Soil Surface of Transitional Amazon Cerrado Forest, Brazil

Measurements of litter production, and the surface litter pool were made over a 1 year period in a tropical transitional forest near Sinop, Mato Grosso Brazil with the aim of quantifying the seasonal variation of nitrogen and phosphorus in the litter and the annual contribution of nutrients to the soil. Average annual litterfall （＋95% confidence interval （CI）） was 8.20 ton.ha^-1 year^-1 and forest floor litter mass was 58.63 ton＇hal. Nitrogen and phosphorus in the forest floor litter mass was highest during the dry and dry-wet season, being 38% higher than in the wet and wet-dry season. Seasonal variation in the litter and concentration of nutrients was explained by seasonal variations in the climate, for example in the precipition and soil humidity. Average annual nitrogen and phosphorus concentrations in the forest floor mass were 17.24 ton.ha^-1 and 16.46 ton.ha^-1, respectively. The more significant forest floor mass fraction for returning soil nutrients was the leaves. The concentration of nutrients was higher in the soil superficial layer （at depths between 0-5 cm） than at depths between 30-70 cm, approximately 83% and 93% for total nitrogen and available phosphorus, respectively.

Determination of Organochlorine Compounds in Sediments from the Upper Middle Sao Francisco River （Bahia, Brazil）

The objective of this study was to determine the contamination of OCPs （organochlorine pesticides） in sediments from the upper middle of Sao Francisco River （Bahia, Brazil） in order to evaluate their potential pollution risks. Samples of surface sediments were collected using a Petersen dredge at 21 stations located between Sobradinho and Cura^i. The organochlorine compounds analyzed were： p,p＇-DDT, p,p＇-DDD, p,p＇-DDE, dicofol, methoxychlor, HCHs, aldrin, endrin, endrin aldehyde, endrin ketone, dieldrin, heptachlor, heptachlor epoxide, endosulfan （ct, fl and sulfate） and chlordane （ct and ,/）. Extractions were carried out using the MAE （microwave-assisted extraction） method and organochlorine pesticides determination was achieved by GC/MS （gas chromatography-mass spectrometry）. Organochlorine concentrations ranged between 1.51-820.00 ng.gx, indicating very low to high levels. The most frequent OCPs were endrin aldehyde, -HCH, HCH, HCH, heptachlor and heptachlor epoxide.

Acid volatile sulfide and simultaneously extracted metals in superficial sediments from Baihua Lake, China

The bioavailability of five divalent cationic heavy metals （Pb, Cd, Cu, Zn and Ni） in 10 superficial sediment samples from Baihua Lake was assessed based on the molar ratio of simultaneously extracted metals （SEMs） to acid volatile sulfide （AVS）. Atomic absorption spectrometry （AAS） and X-ray powder diffraction （XRD） were used to determine the heavy metal concentrations and examine the mineralogy of the crystalline phases, respectively. The AVS loadings in sediments from Baihua Lake ranged from 64.30 to 350.08 ~rnol/g （dry weight）. The corresponding SEM levels for the sampling sites varied from 1.770 to 14.660 vrnol/g. The molar ratio of SEMs to AVS ranged from 0.014 to 0.084 with a mean value of 0.034. The XRD analysis also confirmed the presence of some metal sulfides in sediments from Baihua Lake. The SEMs/AVS ratios for all sampling sites were significantly lower than 1.0, indicating that AVS in the sediments was sufficient to bind the five heavy metals; thus, these heavy metals are currently not significantly bioavailable to benthic organisms. Comparing the SEMs results to published guideline values for metal toxicity to benthic organisms in sediments, however, suggests that Zn and Ni pose a risk at some sampling locations in Baihua Lake.

Geochemical Assessment of Heavy Metals in Surface Sediments： A Case Study of the Tema Port, Ghana

Ten trace and heavy metals （Fe, Mn, Ni, Zn, Cu, Cd, As, Co, Cr and V） were analysed in sediments collected from nine stations at the Tema Port of Ghana, during the dry and wet seasons. Analysis of samples was done using INAA （instrumental neutron activation analysis） for Mn, V, Cu, As and Cd, and AAS （atomic absorption spectrophotometry） for Fe, Cr, Zn, Ni and Co. The concentrations of metals in sediments followed the orders Fe 〉 V〉 Mn 〉 Cd 〉 Ni 〉 Zn 〉 Cu 〉As, for the dry season and Fe 〉 V 〉 Ni 〉 Cu 〉 Zn 〉 Mn 〉 Cd 〉As, for the wet season. Concentrations of Co and Cr were below detection limit, whiles Cu, Cd and Ni were found to be above the TELs （threshold effect levels） of NOAA＇s （National Oceanic and Atmospheric Administration＇s） SQuiRTs （screening quick reference tables） at most sites. Estimated enrichment factors for individual metals showed very high contamination of the port＇s sediments, with Cd occurring at all sites, and Cu, As, V and Ni occurring at some sites for both dry and wet seasons. Although sediments from the Tema Port were highly enriched with Cd, Cu, Ni and V above natural background levels, the overall PLI （pollution load index） per sampling station considering background values of the analysed elements indicated that metal pollution in the port＇s sediment is below 1, indicating relatively unpolluted sediment.

Latitudinal variations of CPI values of long-chain n-alkanes in surface soils:Evidence for CPI as a proxy of aridity

Carbon preference index (CPI) of long-chain n-alkanes preserved in surface soil increases gradually from southeastern China to the north margin of Loess Plateau.Along this latitudinal transect,the CPI value correlates to relative humidity,precipitation,and temperature with a negative linear relationship,respectively,whereas the correlation of CPI to temperature is relatively weak.In the Wuyi,Shennongjia,and Tianshan Mountains,CPI values do not change systemically with altitude increasing (or temperature decreasing).However,mean value of CPI for the individual mountain increases in turn from the humid mountain to the arid.These results jointly suggest that aridity (or humidity) is a dominate climate factor in altering soil CPI value.High CPI values of geological records therefore indicate the arid paleoclimate.Though long-chain n-alkanes in soil are derived mainly from leaf wax of terrestrial vascular plants,the regular latitudinal variations of soil CPI might not be caused by the change of vegetation.We speculate that increased long-chain n-alkanes from microbes and/or enhanced biodegradation in the humid climate lead to the decrease of soil CPI.

Chemical weathering in Malay Peninsula and North Borneo:Clay mineralogy and element geochemistry of river surface sediments

Weathering products of silicate rocks are particularly useful for evaluating the continental chemical weathering on the Earth's surface and its mechanism.Clay mineralogy and major-element geochemistry of surface sediment samples collected in major rivers of Malay Peninsula and North Borneo in the tropical Southeast Asian region are used to study the present chemical weathering process and its controlling factors of tropical regions.The results indicate that the clay mineral assemblage in Malay Peninsula consists dominantly of kaolinite(average 80%) and minor illite(average 17%),almost without chlorite and smectite,whereas in North Borneo it consists mainly of illite and chlorite,with minor amounts of kaolinite(average 14%) and no smectite.Total contents of illite and chlorite in both Northwest and Northeast Borneo are 84% and 87%,respectively.Major-element geochemical results of both bulk and clay-fraction sediments show intensive chemical weathering degree for both areas.Relatively,the chemical weathering degree is gradually strengthened from Northeast Borneo,Northwest Borneo,to Malay Peninsula,and it is extremely intensive in Malay Peninsula.Our results indicate that,in the tropical Southeast Asian region exampled by Malay Peninsula and Borneo,climatic condition of tropical warm temperature and East Asian monsoon rainfall is the first-order controlling factor on the chemical weathering,resulting in intensive chemical weathering throughout tropical areas,and tectonic activity and lithology of parent rocks are subordinate factors,which still have an important impact on the weathering products,forming completely different clay mineral assemblages between Malay Peninsula and Borneo.

A new method to prepare clean cuticular membrane from fossil leaves with thin and fragile cuticles

Leaf cuticle analysis has long been a powerful tool for fossil plant identification, systematics, and palaeoclimatological recon- struction. In recent decades the application of stomatal frequency data that are relied on precise calculation of stomata on plant fossil cuticles to reconstruct ancient atmospheric CO2 concentration made the preparation of cuticular membrane with sufficient size a critical technique in palaeoclimatological research. However, for plants with originally thin and fragile cuticles, e.g., most deciduous plants, conventional techniques sometimes fail to obtain cuticular membranes with sufficient size, or sometimes unable to recover any. This has largely hampered the usage of fossil cuticle analysis in palaeobotanical and palaeo- climatological research. Here, we describe a new method using clear nail polish as a medium to ＂strengthen＂ the originally thin and fragile cuticles prior to maceration procedures. We demonstrate the method by using middle Eocene Metasequoia fossils that were notorious for the difficulty of recovering large-sized clean cuticular membranes due to their thin and fragile nature. Metasequoia, with well-documented and widely-distributed fossil records since the Late Cretaceous and with a living repre- sentative, 114. glyptostroboides, as a comparative reference, bas been widely used as a model genus for the study of evolution of plants, palaeoclimatological reconstruction, and plant adaptation to climate changes. But its deciduous habit produces thin cuticles and makes the preparation of clean cuticular membranes a tedious process. The new method successfully allows us to recover its delicate cuticular membranes with sufficient sizes for SEM observation and stomatal frequency analysis.