Land Management Effects on Biogeochemical Functioning of Salt-Affected Paddy Soils

Most lowlands in Northeast Thailand(Isaan region)are cultivated with rice and large areas are affected by salinity, which drastically limits rice production.A field experiment was conducted during the 2003 rainy season to explore the interactions between salinity and land management in two fields representative of two farming practices:an intensively managed plot with organic inputs and efficient water management,and one without organic matter addition.Field measurements,including pH,Eh,electrical conductivity(EC),and soil solution chemistry,were performed at three depths, with a particular focus on Fe dynamics,inside and outside saline patches. High reducing conditions appeared after flooding particularly in plots receiving organic matter and reduction processes leading to oxide reduction and to the release of Fe and,to a lesser extend,Mn to the soil solution.Oxide reduction led to the consumption of H^+ and the more the Fe reduction was,the higher the pH was,up to 6.5.Formation of hydroxy-green rust were likely to be at the origin of the pH stabilization.In the absence of organic amendments,high salinity prevented the establishment of the reduction processes and pH value remained around 4.Even under high reduction conditions,the Fe concentrations in the soil solution were below commonly observed toxic values and the amended plot had better rice production yield.

Key nitrogen biogeochemical processes revealed by the nitrogen isotopic composition of dissolved nitrate in the Changjiang River estuary, China

Seasonal variations in the nitrogen isotopic composition of dissolved nitrate （δ15NO3） were investigated in the surface waters of the Changjiang River estuary in 2009 and 2010. δ15NO3 varied between -4.6‰ and 8.9%0 with changes in temperature, salinity, dissolved oxygen concentrations, and the composition of the dissolved inorganic nitrogen pool. In February, biological processes decreased because of low temperature, and the mean δ15NO3 near the river mouth was 2.4%0. In May, δ15NO3 was the highest in the surface waters among all seasons. Analysis on the conservative mixing revealed assimilation, and this finding is supported by positive relationship between Chl a and δ15NO3. The fractionation factor of assimilation was estimated to be 2.0‰ by the Rayleigh equation. Nitrification was supported based on the mixing behaviors in November 2010 and the low δ15NO3 values in May and November 2009. The high ammonium concentrations in the adjacent marine area and positive relationships between total organic nitrogen and δ15NO3 in November 2010 indicated that mineralization was taking place.

BIOGEOCHEMICAL PROCESSES OF PHOSPHORUS AND SILICON IN SOUTHERN BOHAI SEA SURFACE SEDIMENTS

Based on the author’s previously obtained results on P and Si forms in southern Bohai Sea surface sediments,this study mainly foucusing on the controlling factors, existence forms, and biogeochemical processes of P and Si showed that the transferable forms of phosphorus in sediments were mainly controlled by the mineralization of organic matters and the reduction of high valence iron; whereas the transferable forms of silicon were possibly controlled by the dissolution and precipitation as well as biochemical processes of living organisms.

Phosphorus Biogeochemical Cycle Research in Mountainous Ecosystems

Phosphorus(P),as a limiting nutrient,plays a crucial role in the mountainous ecosystem development.Its biogeochemical cycle in mountainous ecosystems determines the bioavailability and sustainable supply of P,and thus becomes a crucial process which needs to be fully understood and described for ecological and environmental conservation.However,most of research about P biogeochemical processes has been carried out in aquatic environment and agronomic field,but rare researches have been done in mountain ecosystem.In the present review,we summarize researches on P biogeochemical cycle concerning mountain ecosystem in recent decades,including rock weathering,the release,transformation and bioavailability of P,interactions between the P biological cycle and microbial and plant life,as well as the development of models.Based on the state of art,we propose the future work on this direction,including the integration of all these research,the development of a practical model to understand the P biogeochemical cycle and its bioavailability,and to provide a reference for ecological and environmental conservation of mountainous ecosystems and lowland aquatic systems.

Crystals of suspended marine barite in the eastern equatorial Pacific:processes of dissolution and effects on crystal morphology

Suspended particulate substances were sampled in the eastem equatorial Pacific in water column from surface to near bottom in five stations in 2005, from which 868 barite crystals were recovered. The barite crystals were examined under scanning electron microscopy. About 61% of the total barites crystals contained detectable Sr by energy dispersive X-ray spectrometry. Barite crystals could be classified into four groups based on their morphology： 1） bladed; 2） ovoid or rounded; 3） arrow-like; and 4） irregularly shaped. The arrow-like barite crystals in natural environment has never been reported before. In addition, about a half of the studied crystals showed features of dissolution as cavities or holes inside of the crystals or around their edges. We found that differential dissolution of barite crystals is consequence of heterogeneous Sr distribution in barite crystals. Our results would help in understanding the biogeochemical processes of marine barite formation and preservation in seawater and marine sediments.

Effects of slope position and land use on the stability of aggregateassociated organic carbon in calcareous soils

Topography and land use affect soil organic carbon(SOC) storage, stabilization, and turnover, through several biogeochemical processes. This study investigated the aggregate composition and SOC content of bulk soils and aggregates at different slope positions under different land uses in a typical karst catchment of southwestern China. Our results show that the proportion of macro-aggregates and the SOC content of bulk soils and aggregates at different slope positions decreased from the upper to the lower slope. The SOC content generally increased with an increase in the mean weight diameter and proportion of macro-aggregates under different land uses. Our results indicate that macro-aggregates in forest and grassland soils make a greater contribution to both aggregate composition and SOC content than that in arable land soils. Therefore,converting farmland to forest or grassland can facilitate the accumulation of macro-aggregates as well as the storage of SOC.

Water Chemistry and Hydrometeorology in a Glacierized Catchment in the Polar Urals,Russia

This study aims to determine the relationships between local meteorological conditions,proglacial river discharge and biogeochemical processes operating in a periglacial basin located in the Polar Ural mountain range, Russia. Fieldwork was conducted in the catchment of Obruchev Glacier(13 km2) during the summer peak flow period in 2008. River discharge was dominated by snowmelt and changed from 3300 l s-1 to less than 1000 l s-1. The mean daily air temperatures of stations situated in the mountain tundra and near Obruchev Glacier from July 11 th to August 1st 2008 were 14.4°C and 10.3°C, respectively. The glacial river had low total dissolved solids varying from 4.5 to 9 mg l-1 and coefficients of correlation between Na+ and Cl-, K+ and Cl-, as well as NH4+ and Cl- were 0.94, 0.90 and 0.84, respectively. Rainfall events affected the snowmelt initiation and provided an essential part of the discharge during the intense snowmelt period, which occurred from July 11 th to July 18 th 2008. Data showed that Na+ and K+ in the surface water derived from snowmelt rather than chemical weathering of silicates. Also, it was obtained that NO3- derived from the melting snowpack, whereas ammonification occurring under the snowpacks was the primary source for NH4+.

A Novel Real-time Optimization Methodology for Chemical Plants

In this paper, a novel approach termed process goose queue (PGQ) is suggested to deal with real-time optimization (RTO) of chemical plants. Taking advantage of the ad-hoc structure of PGQ which imitates biologic nature of flying wild geese, a chemical plant optimization problem can be re-formulated as a combination of a multi-layer PGQ and a PGQ-Objective according to the relationship among process variables involved in the objective and constraints. Subsequently, chemical plant RTO solutions are converted into coordination issues among PGQs which could be dealt with in a novel way. Accordingly, theoretical definitions, adjustment rule and implementing procedures associated with the approach are explicitly introduced together with corresponding enabling algorithms. Finally, an exemplary chemical plant is employed to demonstrate the feasibility and validity of the contribution.

Bile acids:Chemistry,physiology,and pathophysiology

The family of bile acids includes a group of molecular species of acidic steroids with very peculiar physical-chemical and biological characteristics.They are synthesized by the liver from cholesterol through several complementary pathways that are controlled by mechanisms involving finetuning by the levels of certain bile acid species.Although their best-known role is their participation in the digestion and absorption of fat,they also play an important role in several other physiological processes.Thus,genetic abnormalities accounting for alterations in their synthesis,biotransformation and/or transport may result in severe alterations,even leading to lethal situations for which the sole therapeutic option may be liver transplantation.Moreover,the increased levels of bile acids reached during cholestatic liver diseases are known to induce oxidative stress and apoptosis,resulting in damage to the liver parenchyma and,eventually,extrahepatic tissues.When this occurs during pregnancy,the outcome of gestation may be challenged.In contrast,the physical-chemical and biological properties of these compounds have been used as the bases for the development of drugs and as pharmaceutical tools for the delivery of active agents.

Physical and chemical processes promoting dominance of the toxic cyanobacterium Cylindrospermopsis raciborskii

The freshwater cyanobacterium, Cylindrospermopsis raciborskii （Woloszyflska） Seenayya and Subba Raju is a common species in lakes and reservoirs globally. In some areas of the world it can produce cytoand hepatotoxins （cylindrospermopsins, saxitoxins）, making blooms of this species a serious health concern for humans. In the last 10 15 years, there has been a considerable body of research conducted on the ecology, physiology and toxin production of this species and this paper reviews these studies with a focus on the cylindrospermopsin （CYN）-producing strains. C. raciborskii has low light requirements, close to neutral buoyancy, and a wide temperature tolerance, giving it the capacity to grow in many lentic waterbodies. It also has a flexible strategy with respect to nitrogen （N） utilisation; being able to switch between utilising fixed and atmospheric N as sources of N fluctuate. Additionally this species has a high phosphate （DIP） affinity and storage capacity. Like many cyanobacteria, it also has the capacity to use dissolved organic phosphorus （DOP）. Changes in nutrient concentrations, light levels and temperature have also been found to affect production of the toxin CYN by this species. However, optimal toxin production does not necessarily occur when growth rates are optimal. Additionally, different strains of C. raciborskii vary in their cell quota of CYN, making it difficult to predict toxin concentrations, based on C. raciborskii cell densities. In summary, the ecological flexibility of this organism means that controlling blooms of C. raciborskii is a difficult undertaking. However, improved understanding of factors promoting the species and toxin production by genetically capable strains will lead to improved predictive models of blooms.

Heavy metal content in coral reef sediments from Red Sea of Yemen and its significance on marine environment

In order to determine and assess the concentrations of trace elements in coral reefs sediments from Red Sea of Yemen, sediment samples were collected, treated and analyzed for cadmium, chromium, cobalt, copper, manganese, nickel, lead, iron, zinc and vanadium by the atomic absorption spectrometric analysis. The result is that cadmium, cobalt and lead concentrations were high and other elements are low or the same as natural background. It is concluded that the high cadmium, cobalt and lead levels in coral reefs sediments will have negative effects on marine life of the sites, so further researches are needed to characterize the sources fate, biogeochemical processes and impacts of these trace elements on coral reefs and marine of the region.

Microaerobic iron oxidation and carbon assimilation and associated microbial community in paddy soil

Iron oxidation is a prevalent and important biogeochemical process in paddy soil,but little is known about whether and how microbially mediated iron oxidation is coupled with carbon assimilation,particularly under microaerobic conditions.Here,we investigated kinetics of CO_2 assimilation and Fe(Ⅱ)oxidation in an incubation experiment with paddy soil under suboxic conditions,and profiled the associated microbial community using DNA-stable isotope probing and 16S r RNA gene-based sequencing.The results showed that CO_2 assimilation and Fe(II)oxidation in the gradient tubes were predominantly mediated by the microbes enriched in the paddy soil,primarily Azospirillum and Magnetospirillum,as their relative abundances were higher in the^( 13)C heavy fractions compared to^( 12)C heavy fractions.This study provided direct evidence of chemoautotrophic microaerophiles linking iron oxidation and carbon assimilation at the oxic–anoxic interface in the paddy soil ecosystem.

Radionuclides and mercury in the salt lakes of the Crimea

^99Sr concentrations, resulting from the Chernobyl NPP accident, were determined in the salt lakes of the Crimea （Lakes Kiyatskoe, Kirleutskoe, Kizil-Yar, Bakalskoe and Donuzlav）, together with the redistribution between the components of the ecosystems. The content of mercury in the waters of the studied reservoirs was also established. Vertical distributions of natural radionuclide activities （^238U, ^232Th, ^226Ra, ^210pb, ^40K） and anthropogenic ^137Cs concentrations （as radiotracers） were determined in the bottom sediments of the Koyashskoe salt lake （located in the south-eastern Crimea） to evaluate the long- term dynamics and biogeochemical processes. Radiochemical and chemical analysis was undertaken and radiotracer and statistical methods were applied to the analytical data. The highest concentrations of ^99Sr in the water of Lake Kiyatskoe （350.5 and 98.0 Bq/m^3） and Lake Kirleutskoe （121.3 Bq/m^3） were due to the discharge of the Dnieper water from the North-Crimean Canal. The high content of mercury in Lake Kiyatskoe （363.2 ng/L） and in seawater near Lake Kizil-Yar （364 ng/L） exceeded the maximum permissible concentration （3.5 times the maximum）. Natural radionuclides provide the main contribution to the total radioactivity （artificial and natural combined） in the bottom sediments of Lake Koyashskoe. The significant concentration of ^210pb in the upper layer of bottom sediments of the lake indicates an active inflow of its parent radionuclide-gaseous ^222Rn from the lower layers of the bottom sediment. The average sedimentation rates in Lake Koyashskoe, determined using ^210pb and ^137Cs data, were 0.117 and 0.109 cm per year, respectively.

Physical, Chemical and Biochemical Changes of Sweetsop （Annona squamosa L.） and Golden Apple （Spondias citherea Sonner） Fruits during Ripening

This study aimed at the physical, chemical and biochemical changes during ripening of Sweetsop （Annona squamosa L.） and Golden Apple （Spondias citherea Sonner） fruits during ripening as important features to better understand their postharvest handling. It was carried out physical analysis such as firmness and chemical analysis such as total chlorophyll, total carotenoids, soluble solids, pectins and titrable acidity and biochemical analysis such as pectin methyl esterase, polygalacturonase, cellulase, and peroxidase and polyphenoloxidase activities in crude extract. Fruits were harvested at different stages of ripening. Experimental design was completely randomized and was carried out analysis of variance and Tukey tests, Total chlorophyll was decreasing in later stages of ripening, total soluble solid contents increased as the fruits ripen, while the acidity expressed percentage of citric acid decreased during fruits ripening. The loss of firmness and soluble solids content increased as the fruit get ripped stage, while the content of pectin decreased. Activity was observed for pectin methyl esterase and polygalacturonase enzymes during all stages of maturation, presenting the highest activity for both enzymes in the mature state. No cellulase activity detected at any stage during the ripening of these fruits. Activity of the enzyme polyphenoloxidase and peroxidase, associated with pulp browning was higher in the last stages of ripening of these fruits. Physical, chemical and biochemical patterns during ripening were different according to fruit species suggesting differential postharvest handling requirements.

Biogeochemistry of methanogenesis with a specific emphasis on the mineral-facilitating effects

The Earth surface contains various oxic and anoxic environments. The later include natural wetlands,river and lake sediments, paddy field soils and landfills. In the last few decades, the biogeochemical cycle of carbon in anoxic environments, which leads to the production and emission of methane, a potent greenhouse gas in the atmosphere, has drawn great attentions from both scientific and public sectors. New organisms and mechanisms involved in methanogenesis and carbon cycling have been uncovered. Interspecies electron transfer is considered as a crucial step in methanogenesis in anoxic environments.Electron-carrying mediators, like H_2 and formate, are known to play the key role in electron transfer. Recently, it has been found that in addition to the conventional electron transfer via chemical mediators, direct interspecies electron transfer(DIET) can occur. In this Review, we describe the ecology and biogeochemistry of methanogenesis and highlight the effect of microbe-mineral interaction on microbial syntrophy. Recent advances in the study of DIET may pave the way towards a mechanistic understanding of methanogenesis and the influence of microbe-mineral interaction on this process.

Physico-Chemical and Microbiological Properties of a Traditional Turkey Cheese Tomas/Serto （Dorak）

Turkey is a country producing various kinds of cheese. Tomas cheese is a kind of cheese that is still traditionally produced, and it is not widely-known. In this study, the characteristic properties of Tomas cheese, a local product that is extensively consumed in the city of Tunceli and its environs, have been examined. For this purpose, samples from cheese varieties currently on sale in the cities of Tunceli and Elazl~ have been taken, and some of their physico-chemical and microbiological properties have been determined. The results of physico-chemical analysis showed that the average moisture rate of the samples was 53.24%, average ash rate 4.24%, average dry matter 46.76%, average acidity rate in terms of lactic acid 1.08%, average salt rate 2.93%, average fat rate 17.66%, average fat-free dry matter rate 25.56% and average pH value 4.67. The microbiological analysis data showed that the average values for the total aerobic mesophyll bacteria （TAMB） was 7 loglo kob/g, 2.3 logl0 kob/g for coliform, 4.6 logl0 kob/g for yeast, 5.5 logl0 kob/g for mold, 6.8 log10 kob/g for Lactococcus spp., and 6.1 log10 kob/g for Lactobacillus spp.. The results show the high variation among samples, proving that there has not been a standard production procedure. It has been established that the hygienic condition of the product changes according to the production process, and the probability for cross contamination is high. A large number of studies need to be carded out for this kind of traditional food items, due to lack of enough literature data in this paper.

Formation of passivation film during pyrrhotite bioleached by pure L. ferriphilum and mixed culture of L. ferriphilum and A. caldus

Bioleaching and electrochemical experiments were conducted to evaluate pyrrhotite dissolution in the presence of pure L.ferriphilum and mixed culture of L. ferriphilum and A. caldus. The results indicate that the pyrrhotite oxidation behavior is the preferential dissolution of iron accompanied with the massive formation of sulfur in the presence of L. ferriphilum, which significantly hinders the leaching efficiency. Comparatively, the leaching rate of pyrrhotite distinctly increases by 68% in the mixed culture of L. ferriphilum and A. caldus at the 3rd day. But, the accumulated ferric ions and high p H value produced by bioleaching process can give rise to the rapid formation of jarosite, which is the primary passivation film blocking continuous iron extraction during bioleaching by the mixed culture. The addition of A. caldus during leaching by L. ferriphilum can accelerate the oxidation rate of pyrrhotite, but not change the electrochemical oxidation mechanisms of pyrrhotite. XRD and SEM/EDS analyses as well as electrochemical study confirm the above conclusions.

Exotic Beam for Direct Measurement of the 22^Mg＋a

The scattering and resonance reactions of ^22Mg＋p and ^22Mg＋α play crucial roles for studying deeply not only in the structure of proton-rich nuclei of ^23A1 and ^26Si but also for the interest of astrophysics. It is believed that ^22Mg nucleus is a waiting point in the αp-process of nucleosynthesis in novae. We supposed to perform direct measurement the ^22Mg＋α system in invert kinematics using radioactive ion （RI） beam. The ^22Mg beam of 3.73 MeV/u was produced at CRIB facility of the University of Tokyo located at RIKEN, Japan in 2011. In this paper, we report the results the scattering and resonance reactions with the alpha target. of the ^22Mg beam production used for the direct measurement of

Removal of Pharmaceutically Active Compounds in Sequencing Batch Reactor

Biological treatment efficiency of six pharmaceutical compounds （acetazolamide, metronidazole, opipramol, piracetam, salicylamide and tinidazole） was evaluated using lab-scale Sequencing Batch Reactor （SBR）. Comparative biological degradation processes of two types of activated sludge from municipal and pharmaceutical industry sewage treatment plants were examined. Three different organic loadings （0.05 g COD/g MLSS.d, 0.1 g COD/g MLSS.d and 0.2 g COD/g MLSS-d） and reaction time on the efficiency of Active Pharmaceutical Ingredient （API） decomposition were examined. Chemical oxygen demand, non-purgeable organic carbon as well as ammonium nitrogen contents were monitored by standard methods. Percentage of API decomposition was analysed by High Performance Liquid Chromatography （HPLC）. The overall API removal efficiency was strictly dependent on the type of activated sludge origin. The main biodegradation products were identified using HPLC-MS,1H NMR and 13C NMR methods as e.g. （{4-[3-（5H-dibenzo[b,f]azepin-5-yl]piperazin-l-yl}methanamine） and （2-amino-1,3,4-thiadiazol-5-sulfonamide） for opipramol and acetazolamide respectively.

海洋次表层叶绿素最大值的特征因子及其影响因素

在多数情况下,海水中叶绿素垂直分布是不均匀的。次表层叶绿素最大值是其中较为常见的一种形式,普遍存在于大洋及沿岸海域。次表层叶绿素最大值层(SCML)的深度、厚度与强度是表征海洋次表层叶绿素最大值(SCM)现象的主要特征因子,受海洋水文环境、营养盐分布以及浮游植物种类等因素共同影响,在不同季节不同海区的分布有较大差异。总体上,相对近海,大洋中SCML特征因子的季节变化较小,SCML深度较大,厚度较大,强度较小。寡营养盐海区SCML深度及强度的影响因素研究已有较明确结论,SCML深度主要受物理因素(光照条件及水体混合程度)影响,而强度则受物理、生物因素(光照条件、水体混合程度或浮游动物摄食等)共同影响。近海富营养盐海区,SCML特征因子的影响因素研究较为薄弱。长时间序列、高分辨率观测站在相应海区的建立,对推进海洋SCM,尤其是近海SCM的研究有重要意义。卫星观测、现场观测和数学模型相结合,定量研究SCML特征因子与各物理、生物、化学因子的普适性关系,是进一步研究SCML特征因子的重要方向之一。