念青唐古拉山扎当冰川雪冰中不溶性有机碳含量及其辐射强迫研究

为了研究雪冰中不溶性有机碳(Water-insoluble Organic Carbon,WISOC)的含量及其辐射强迫作用,于2012年7月和8月对青藏高原南部纳木错流域扎当冰川90个表层雪冰样品中WISOC的含量进行了分析,采样期间利用地物光谱仪实地测量了反照率.结果表明,在消融季节(7—8月),扎当冰川表面被裸冰、老雪和新雪覆盖,以上3种消融情形下WISOC的平均含量分别为(1618.4±1236.0)、(432.3±329.7)和(183.7±158.0)ng·g-1,雪冰的融化导致WISOC等吸光性物质在冰川表面的富集,降低了冰川表面反照率.通过SNICAR模型(Snow,Ice,and Aerosol Radiative Modle)敏感性分析表明,3种情形下WISOC降低雪冰表面反照率(贡献率)分别为0.0020(6.8%)、0.0018(7.4%)和0.0010(2.1%),对应的WISOC的辐射强迫分别为1.14、1.34和0.81 W·m-2.平均地,WISOC对辐射强迫的影响超过了黑碳(BC)影响的20%,而在新雪覆盖条件下,WISOC对辐射强迫的影响甚至达到了粉尘影响的72.3%.因此,虽然雪冰中的WISOC的吸光能力相对于BC较弱,但所引起的雪冰表面反照率降低及冰川消融等效应不容忽视.

土壤活性有机质(碳)的内涵和现代分析方法概述

土壤有机物质的活性成分是对土壤养分、植物生长乃至环境、大气和人类有影响的有效物质。在现代土壤研究中 ,出现了与之相关的繁多术语和应用指标 ,但是它们的内涵尚为混乱 ,其分析方法也缺乏系统的归纳。本文对土壤溶性有机碳 (DOC)和水溶性有机碳 (WSOC)、土壤有效碳 (AC)、土壤潜在可矿化碳 (PMC)、土壤易氧化碳 (ROC)、土壤微生物量碳 (SMBC)、土壤轻组有机碳 (LF C)几种较为普遍应用的土壤活性有机质 (碳 )从概念指标、分析意义到分析方法做了较系统的描述与理顺 ,以期对土壤有机质应用上的研究起到积极作用。

Effect of Different Fertilization Patterns on Carbon and Nitrogen Components of Tobacco Topsoil

In order to explore the fertilizing ways and dynamic changes of soil carbon and nitrogen in the main producing areas of tobacco in Guizhou,research was conducted to study the variations of dissolved organic carbon and nitrogen,total organic carbon and nitrogen and their ratio of tobacco-topsoil in organic fertilization pattern and conventional cultivation pattern （No fertilizer as control） by pot experiment.The results were as follows：（1） The effects of different fertilization patterns on soil dissolved organic carbon and nitrogen and total organic carbon and nitrogen were significantly different.The content of DOC,DON,TOC and TON in tobaccotopsoil was decreased with the advancing of growth period in conventional fertilization pattern.In the conventional fertilization pattern,the accumulation of DOC and TOC was increased first and then decreased,and the accumulation of DON and TON was decreased first and then increased.（2） The TOC content at the different growing stage and DOC content at the middle and later stage of tobacco were significantly improved in organic fertilization patterns.The accumulation of DON and TON in the conventional fertilization pattern was significantly higher than those in the organic fertilizer pattern and control at the rosette stage and vigorous stage.In the harvest period,the content of DOC,DON,TOC and TON of tobacco-topsoil in the conventional fertilization and organic fertilization pattern was significantly higher than those in the control.（3）The DOC/DON ratio and the TOC/TiON ratio was increased gradually with the advancing of growth period in conventional fertilization pattern,but they were increased first and then decreased in the organic fertilization pattern and CK.The DOC/DON and TOC/TON ratio of tobacco-topsoil in different fertilization patterns was showed as Y J＞ CK＞ CG at the different growing stage.The experiment results revealed that：The organic fertilization pattern may improve significantly the accumulation of DOC,DON,TOC and TON of tobacco-topsoil at the middle and later stage and the DOC/DON and TOC/TON ratio at the different growth stage.It contributed to the continuous and balanced supply of nutrients at the middle and later stage of tobacco and the soil fertility.

Ozonation and Biodegradability of Lignin in Water

To convert the non biodegradable sodium lignin sulfonate into biodegradable substances, the sodium lignin sulfonate in the water was ozonized and the pH value, dissolved organic carbon(DOC), ultraviolet absorbency at λ =254 nm(UVA) and the biodegradability of the ozonation effluent were measured. The non biodegradable sodium lignin sulfonate can be partly converted into biodegradable substances by ozonation (about 38 76%). In the ozonation process, there is little DOC decrease, but much UVA decrease and obvious pH drop.

Effects of Fertilization Types and Cultivation Years on Dissolved Organic Carbon(DOC) in Paddy Soil under Water-logging Condition

In this study, the spatial and temporal distribution characteristics of dis- solved organic carbon （DOC） in water-logged paddy soil in Yanbian were investigat- ed under conditions of different fertilization types （single application of chemical fer- tilizer, mixed application and chemical and organic fertilizers and single application of organic fertilizer） and cultivation years （80 years and 120 years）. The results showed that the spatial and temporal distribution of DOC in water-logged paddy soil changed significantly with time going by. The single application of chemical fertilizer or mixed application of chemical and organic fertilizers contributed to the release of DOC in top paddy soil under water-logging condition; the single application of organ- ic fertilizer promoted the accumulation of DOC in bottom paddy soil, resulting in great heterogeneity of DOC in the vertical space, but the single application of chem- ical fertilizer weakened the vertical spatial heterogeneity of soil DOC; the DOC con- tent in the 80-year-old water-logged paddy soil was higher and more stable than that in the 120-year-old soil.

Chemical characterization and composition of dissolved organic matter in Jiaozhou Bay

Biologically utilizable dissolved organic compounds,including dissolved organic carbon (DOC),dissolved carbohydrates (DCHO) and dissolved free amino acids (DFAA) were analyzed in filtered surface seawater samples collected at 19 stations in Jiaozhou Bay,China,on June 3,2007.In these samples,concentrations of DOC,dissolved free carbohydrates (DFCHO),dissolved combined carbohydrates (DCCHO),total dissolved carbohydrates (TDCHO) and total dissolved free amino acids (TDFAA) ranged from 141.7 to 191.1 μmol C/L,1.98 to 18.18 μmol C/L,5.04 to 24.90 μmol C/L,14.52 to 30.36 μmol C/L,and 1.83 to 11.89 μmol C/L,respectively.As a major component of the dissolved carbohydrates,the concentrations of DCCHO were about three times higher than those of DFCHO.Three major constituents of the DFAA were threonine (23.0±5.7 mol%),glutamic acid (16.6±3.2 mol%) and arginine (9.1±3.3 mol%).Based on the composition of DFAA,a molar C:N ratio of 3.60±0.75 in DFAA was derived,indicating longer carbon chains in the amino acids.DCCHO (8.1%) was the most abundant fraction of DOM in most samples,followed by DFCHO (4.8%) and TDFAA (2.7%).These DOM concentrations displayed a decreasing trend from the coast to the central region.Significant correlations were found between the DCCHO and DFCHO concentrations (r=-0.724,n=19,P<0.001) and the DCCHO and TDCHO concentrations (r=0.506,n=19,P=0.027).

Removal and transformation of dissolved organic matter in secondary effluent during granular activated carbon treatment

This paper focused on the removal and transformation of the dissolved organic matter （DOM） in secondary effluent during the granular activated carbon （GAC） treatment. Using XAD-8/XAD-4 resins, DOM was fractionated into five classes： hydrophobic acid （HPO-A）, hydrophobic neutral （HPO-N）, transphilic acid （TPI-A）, transphilic neutral （TPI-N） and hydrophilic fraction （HPI）. Subsequently, the water quality parameters of dissolved organic carbon （DOC）, absorbance of ultraviolet light at 254 nm （UV-254）, specific ultraviolet light absorbance （SUVA） and trihalomethane formation potential （THMFP） were analyzed for the unfractionated and fractionated water samples. The results showed that the order of the DOC removal with respect to DOM fractions was observed to be HPI〉HPO-A〉HPO-N〉TPI-A〉TPI-N. During the GAC treatment, the THMFP of the unfractionated water samples decreased from 397.4 μg/L to 176.5 μg/L, resulting in a removal efficiency of 55.6%. The removal order of the trilaalomethanes （THMs） precursor was as follows： HPO-A〉TPI-A〉TPI-N〉HPO-N〉HPI. By the GAC treatment, the specific THMFP of HPO-A, TPI-A, TPI-N and the original unfractionated water samples had a noticeable decrease, while that of HPO-N and HPI showed a converse trend. The Fourier transform infrared （FTIR） results showed that the hydroxide groups, carboxylic acids, aliphatic C-H were significantly reduced by GAC treatment.

Spatiotemporal variation of dissolved carbohydrates and amino acids in Jiaozhou Bay,China

Surface seawater samples were collected from Jiaozhou Bay,China,during six cruises(MarchMay 2010,September-November 2010) to study the distribution of dissolved organic matter including dissolved organic carbon(DOC),total dissolved carbohydrates,namely monosaccharides(MCHO) and polysaccharides(PCHO) and total hydrolysable amino acids.These included dissolved free amino acids(DFAA) and combined amino acids(DCAA).The goal was to investigate possible relationships between these dissolved organic compounds and environmental parameters.During spring,the concentrations of MCHO and PCHO were 9.6(2.8-22.6) and 11.0(2.9-42.5) μmol C/L,respectively.In autumn,MCHO and PCHO were 9.1(2.6-27.0) and 10.8(2.4-25.6) μmol C/L,respectively.The spring concentrations of DFAA and DCAA were 1.7(1.1-4.1) and 7.6(1.1-31.0) μmol C/L,respectively,while in autumn,DFAA and DCAA were 2.3(1.1-8.0) and 3.3(0.6-7.2) μmol C/L,respectively.Among these compounds,the concentrations of PCHO were the highest,accounting for nearly a quarter of the DOC,followed by MCHO,DCAA and DFAA.The concentrations of the organic compounds exhibited a decreasing trend from the coastal to the central regions of the bay.A negative correlation between concentrations of DOC and salinity in each cruise suggested that riverine inputs around the bay have an important impact on the distribution of DOC in the surface water.A significant positive correlation was found between DOC and total bacteria count in spring and autumn,suggesting bacteria play an important role in the marine carbon cycle.

Pilot study on combined process of catalytic ozonation and biological activated carbon for organic pollutants removal

A combined process of catalytic ozonation in the presence of a novel heterogeneous catalyst and biological activated carbon was investigated for the removal of priority control organic pollutants, the reduction of genotoxicity, and the improvement of biodegradable dissolved organic carbon (BDOC). Results confirm that the catalytic ozonation has higher effectiveness for the removal of refractory harmful organic pollutants, the reduction of genotoxicity and the increase of bio-degradability of organics than ozonation alone, which results in lower pollution load for subsequent biological activated carbon process, and then leads to less organic pollutants penetrating biological activated carbon. The novel catalytic ozonation with this combined process exhibits excellent performance to guarantee the safety of drinking water.

Isotopic and Chemical Characteristics of Lagoon Waters in Niigata Prefecture, Japan

In order to investigate the isotopic and chemical characteristics of lagoon waters in Niigata Prefecture in recent years, oxygen and hydrogen stable isotope ratios （i.e., 8180 and 6D）, the concentrations of DOC （dissolved organic carbon）, DO （dissolved oxygen） and pH, etc. in water samples of Sakata and Toyanogata were measured. Samples were generally taken monthly at the fixed sampling points from these lagoons. Consequently, the following matters have been mainly clarified： （1） ~D value of water samples in Sakata was generally larger than that in Toyanogata similarly to the case of ~180, though remarkable large difference among samples was not found; （2） the pH value of lagoon water samples is almost 6.5-8.5 （which is generally larger than that of river water）, and pH at the spot of SI （downstream point of Lower Lagoon （Shitakata）） is remarkably high （9.0-9.5）; （3） Lagoon water has the chemical characteristics contrasting to groundwater with a focus on river water from the viewpoint of pH （acidity or alkalinity） and DO. These matters can be closely related to the biological activity such as photosynthesis due to aquatic plant and phytoplankton and the activity of Crustacea plankton etc. in lagoon.

Effect of Vegetation Succession on Organic Carbon,Carbon of Humus Acids and Dissolved Organic Carbon in Soils of Copper Mine Tailings Sites

Carbon of humus acids(HSAC) and dissolved organic carbon(DOC) are the most active forms of soil organic carbon(SOC) and play an important role in global carbon recycling. We investigated the concentrations of HSAC,water-soluble organic carbon(WSOC),hot water-extractable organic carbon(HWOC) and SOC in soils under different vegetation types of four copper mine tailings sites with differing vegetation succession time periods in Tongling,China. The concentrations of HSAC,WSOC,HWOC and SOC increased with vegetation succession. WSOC concentration increased with the accumulation of SOC in the tailings,and a linearly positive correlation existed between the concentrations of HSAC and SOC in the tailings. However,the percentages of HSAC and DOC in the SOC decreased during vegetation succession. The rate of SOC accumulation was higher when the succession time was longer than 20 years,whereas the speeds of soil organic matter(SOM) decomposition and humification were slow,and the concentrations of HSAC and DOC increased slowly in the tailings. The percentage of carbon of humic acid(HAC) in HSAC increased with vegetation succession,and the values of humification index(HI),HAC/carbon of fulvic acid,also increased with the accumulation of HSAC and SOC in soils of the tailings sites. However,the HI value in the each of the tailings was less than 0.50. The humification rate of SOM was lower than the accumulation rate of SOM,and the level of soil fertility was still very low in the tailings even after 40 years of natural restoration.

Sorption of Water-Extractable Organic Carbon in Various Clay Subsoils: Effects of Soil Properties

Clay-rich subsoils are added to sandy soils to improve crop yield and increase organic carbon （C） sequestration; however, little is known about the influence of clay subsoil properties on organic C sorption and desorption. Batch sorption experiments were conducted with nine clay subsoils with a range of properties. The clay subsoils were shaken for 16 h at 4 ℃with water-extractable organic C （WEOC, 1 224 g C L-1） from mature wheat residue at a soil to extract ratio of 1：10. After removal of the supernatant, the residual pellet was shaken with deionised water to determine organic C desorption. The WEOC sorption was positively correlated with smectite and illite contents, cation exchange capacity （CEC） and total organic C, but negatively correlated with kaolinite content. Desorption of WEOC expressed as a percentage of WEOC sorbed was negatively correlated with smectite and illite contents, CEC, total and exchangeable calcium （Ca） concentrations and clay content, but positively correlated with kaolinite content. The relative importance of these properties varied among soil types. The soils with a high WEOC sorption capacity had medium CEC and their dominant clay minerals were smectite and illite. In contrast, kaolinite was the dominant clay mineral in the soils with a low WEOC sorption capacity and low-to-medium CEC. However, most soils had properties which could increase WEOC sorption as well as those that could decrease WEOC sorption. The relative importance of properties increasing or decreasing WEOC sorption varied with soils. The soils with high desorption had a low total Ca concentration, low-to-medium CEC and low clay content, whereas the soils with low desorption were characterised by medium-to-high CEC and smectite and illite were the dominant clay minerals. We conclude that WEOC sorption and desorption depend not on a single property but rather a combination of several properties of the subsoils in this study.

The research of typical microbial functional group reveals a new oceanic carbon sequestration mechanism——A case of innovative method promoting scientific discovery

Marine microbes are major drivers of marine biogeochemical cycles and play critical roles in the ecosystems. Aerobic anoxygenic phototrophic bacteria(AAPB) are an important bacterial functional group with capability of harvesting light energy and wide distribution, and appear to have a particular role in the ocean's carbon cycling. Yet the global pattern of AAPB distribution was controversial at the beginning of the 21 st century due to the defects of the AAPB enumeration methods. An advanced time-series observation-based infrared epifluorescence microscopy(TIREM) approach was established to amend the existing AAPB quantitative deviation and led to the accurate enumeration of AAPB in marine environments. The abundance of AAPB and AAPB% were higher in coastal and continental shelf waters than in oceanic waters, which does not support the idea that AAPB are specifically adapted to oligotrophic conditions due to photosynthesis in AAPB acting a supplement to their organic carbon respiration. Further investigation revealed that dependence of AAPB on dissolved organic carbon produced by phytoplankton(PDOC) may limit their competition and control AAPB distribution. So, the selection of carbon sources by AAPB indicated that they can effectively fractionate the carbon flow in the sea. Enlightened by these findings, the following studies on the interactions between marine microbes and DOC led to the discovery of a new mechanism of marine carbon sequestration—the Microbial Carbon Pump(MCP). The conceptual framework of MCP addresses the sources and mechanism of the vast DOC reservoir in the ocean and represents a breakthrough in the theory of ocean carbon sequestration.