Impacts of low-intensity prescribed fire on microbial and chemical soil properties in a Quercus frainetto forest

Prescribed fire is a common economical and effective forestry practice, and therefore it is important to understand the effects of fire on soil properties for better soil management. We investigated the impacts of low-intensity prescribed fire on the microbial and chemical properties of the top soil in a Hungarian oak(Quercus frainetto Ten.) forest. The research focused on microbial soil parameters(microbial soil respiration(RSM), soil microbial biomass carbon(Cmic) and metabolic quotient(qCO2) and chemical topsoil properties(soil acidity(pH),electrical conductivity(EC), carbon(C), nitrogen(N), C/N ratio and exchangeable cations). Mean annual comparisons show significant differences in four parameters(C/N ratio,soil pH, Cmic and qCO2) while monthly comparisons do not reveal any significant differences. Soil pH increased slightly in the burned plots and had a significantly positive correlation with exchangeable cations Mg, Ca, Mn and K.The mean annual C/N ratio was significantly higher in the burned plots(28.5:1) than in the control plots(27.0:1). The mean annual Cmic(0.6 mg g-1) was significantly lower although qCO2(2.5 lg CO2–C mg Cmic h-1) was significantly higher, likely resulting from the microbial response to fire-induced environmental stress. Low-intensity prescribed fire caused very short-lived changes. The annual mean values of C/N ratio, pH, Cmic and qCO2showed significant differences.

Seasonal Dynamics of Nutrient Loading and Chlorophyll A in a Northern Prairies Reservoir, Saskatchewan, Canada

Harmful algae blooms have become an increasing concern in context with the safety of water resources around the globe;however, little is known about the dynamics and specific causes of such blooms in the prairie ecozone in North America. The aim of this study was to research the nitrogen (N) and phosphorous (P) content and nutrient limitation (defined as N and P limitation) of growth of cyanobacteria in a northern prairies reservoir (Lake Diefenbaker [LD], SK, Canada). A combination of concentration balance analysis for N and P, controlled bioassays with the natural consortium of phytoplankton or defined monocultures of cyanobacteria, and satellite imagery was applied to address this aim. The current trophic status of Lake Diefenbaker is one of moderate eutrophication. Primary production in the lake is P-limited, and N did not represent a limiting factor for algal production. There was no significant increase in TP con- centrations between the upper and lower portions of the reservoir, indicating that most of the phosphorus in LD comes from upstream sites in Alberta. Anabaena circinalis, a species that has the potential to seriously degrade lake ecosys- tems, was identified as the predominant cyanobacteria in LD. Together with the fact that TP influxes into the reservoir primarily originate from upstream sources, these results suggest the need for remedial measures in the upstream reach of the South Saskatchewan River. Satellite imaging represented a promising approach in support of monitoring for po- tential algal blooms in LD;however, due to limited sensitivity and issues associated with atmosphere interference this methodology should only be used in combination with in situ water quality monitoring. In summary, while this study indicated that Lake Diefenbaker is potentially at risk with cyanobacteria blooms (some of which such as Anabena sp. that can produce toxins) during late summer and fall, development of clear causal relationships and risk assessment strategies is currently limited due to lack of monitoring data and programs.

Carbon and nitrogen storage in an age-sequence of Pinus densiflora stands in Korea

The carbon(C) and nitrogen(N) storage capabilities of Pinus densiflora in six different stand ages(10,27,30,32,44,and 71 years old) were investigated in Korea.Thirty sample trees were destructively harvested and 12 were excavated.Samples from the above and belowground tree components,coarse woody debris(CWD),forest floor,and mineral soil(0-30 cm) were collected.Tree biomass was highest in the 71-year-old stand(202.8 t ha-1) and lowest in the 10-year-old stand(18.4 t ha-1).C and N storage in the mineral soil was higher in the 71-year-old stand than in the other stands,mainly due to higher soil C and N concentrations.Consequently,the total ecosystem C and N storage(tree+forest floor+CWD+soil) was positively correlated with stand age:increasing from a minimum in the 10 year old stand(18.8 t C ha-1 and 1.3 t N ha-1) to a maximum in the 71-year-old stand(201.4 t C ha-1 and 8.5 t N ha-1).The total ecosystem C storage showed a similar sigmoidal pattern to that of tree C storage as a function of the age-sequence,while N storage in the CWD,forest floor and mineral soil showed no significant temporal trends.Our results provide important insights that will increase our understanding of C and N storage in P.densiflora stands and our ability to predict changes according to stand age in the region.

Estimation of carbon storage based on individual tree detection in Pinus densiflora stands using a fusion of aerial photography and LiDAR data

The objective of this study was to estimate the carbon storage capacity of Pinus densiflora stands using remotely sensed data by combining digital aerial photography with light detection and ranging(LiDAR) data.A digital canopy model(DCM),generated from the LiDAR data,was combined with aerial photography for segmenting crowns of individual trees.To eliminate errors in over and under-segmentation,the combined image was smoothed using a Gaussian filtering method.The processed image was then segmented into individual trees using a marker-controlled watershed segmentation method.After measuring the crown area from the segmented individual trees,the individual tree diameter at breast height(DBH) was estimated using a regression function developed from the relationship observed between the field-measured DBH and crown area.The above ground biomass of individual trees could be calculated by an image-derived DBH using a regression function developed by the Korea Forest Research Institute.The carbon storage,based on individual trees,was estimated by simple multiplication using the carbon conversion index(0.5),as suggested in guidelines from the Intergovernmental Panel on Climate Change.The mean carbon storage per individual tree was estimated and then compared with the field-measured value.This study suggested that the biomass and carbon storage in a large forest area can be effectively estimated using aerial photographs and LiDAR data.

Recent advances in controlled modification of the size and morphology of metal-organic frameworks

Advances in metal-organic frameworks （lVIOFs） resulted in significant contributions to diverse applications such as carbon capture, gas storage, heat transformation and separation along with emerging applications toward catalysis, medical imaging, drug deliver~ and sensing. The unique in situ and ex situ structural features of MOFs can be tailored by conceptual selection of the organic （e.g., ligand） and inorganic （e.g., metal） components. Here, we provide a comprehensive review on the synthesis and characterization of MOFs, particularly with respect to controlling their size and morphology. A better understanding of the specific size and morphological parameters of MOFs will help initiate a new era for their real-world applications. Most importantly, this assessment will help develop novel synthesis methods for MOFs and their hybrid/porous materials counterparts with considerably improved properties in targeted applications.

Radial growth response of Pinus densiflora and Quercus spp.to topographic and climatic factors in South Korea

Aims This study aimed to develop radial growth models and to predict the potential spatial distribution of Pinus densiflora(Japanese red pine)and Quercus spp.(Oaks)in South Korea,considering topographic and climatic factors.Methods We used a dataset of diameter at breast height and radial growth estimates of individual trees,topographic and climatic factors in systematic sample plots distributed over the whole of South Korea.On the basis that radial growth is attributed primarily to tree age,we developed a radial growth model employing tree age as an explanatory variable.We estimated standard growth(SG),defined as radial growth of the tree at age 30,to eliminate the influence of tree age on radial growth.In addition,SG estimates including the Topographic Wetness Index,temperature and precipitation were calculated by the Generalized Additive Model.Important Findings As a result of variogram analysis of SG,we found spatial autocorrelation between SG,topographic and climatic factors.Incremental temperature had negative impacts on radial growth of P.densiflora and positive impacts on that of Quercus spp.Precipitation was associated with positive effects on both tree species.Based on the model,we found that radial growth of P.densiflora would be more vulnerable than that of Quercus spp.to climatic factors.Through simulation with the radial growth model,it was predicted that P.densiflora stands would be gradually replaced with Quercus spp.stands in eastern coastal and southern regions of South Korea in the future.The models developed in this study will be helpful for understanding the impact of climatic factors on tree growth and for predicting changes in distribution of P.densiflora and Quercus spp.due to climate change in South Korea.

Nontarget screening using passive air and water sampling with a level Ⅱ fugacity model to identify unregulated environmental contaminants

It is thought that there are many unregulated anthropogenic chemicals in the environment.For risk assessment of chemicals, it is essential to estimate the predicted environmental concentrations. As an effort of identifying residual organic contaminants in air and water in Korea, nontarget screening using two-dimensional gas chromatography time-of-flight mass spectrometry（GC × GC-TOFMS） was conducted at 10 sites using polyurethane foam passive air sampler and at 6 sites using polydimethyl siloxane（PDMS） passive water sampler in three different seasons in 2014. More than 600 chemical peaks were identified satisfying the identification criteria in air and water samples, respectively, providing a list for further investigation. Chemical substances with reported national emission rates in2014（n = 149） were also screened for potential existence in the environment using a level Ⅱ fugacity model. Most of chemical substances classified as not detectable were not identified with detection frequency greater than 20% by nontarget screening, indicating that a simple equilibrium model has a strong potential to be used to exclude chemicals that are not likely to remain in the environment after emissions from targeted monitoring.

Comparing End-Use Potential for Industrial Food-Waste Sources

全球大约有1/4的可食用的食物被浪费。食物浪费的驱动因素可以发生在生产、收获、分销、加工和消费之间的任何阶段。尽管全球各地的驱动因素不同,但在北美洲、欧洲和亚洲的工业化地区有着相类似的情况。在这些地区,食物浪费最严重的情况发生在消费者环节,他们产生了大约51%的食物废物。因此,处理垃圾的重点就落在了处理城市固体废物上。在美国,食物垃圾占固体废物流重量的15%,产生的CO_2当量排放量多达3.4×10~7 t,其处置费用高达19亿美元。利用食物垃圾中含有的碳、营养物和水分使垃圾转化成为高附加值产品,这对于减少浪费是一种具有吸引力的方法。提取食物垃圾中的营养物质和生物活性物质,或者把两者转化为各种挥发性酸碱(包括乳酸、乙酸和丙酸),便可以利用这些机会回收废物并将产品出售以获得利润。废物转化为挥发性酸的过程可以与生物能源(如氢气和沼气)生产相结合。本文将食物废物制备成某种高附加值产品或甲烷的潜力进行了对比。高价值利用食物垃圾可以减轻大约1.9×10~8 t CO_2当量排放。以马铃薯皮为例,通过发酵技术将其转化为乳酸可每年节省56亿美元,也可以通过厌氧消化转化为甲烷,每年增收9亿美元。回收食物废物潜在价值巨大,而食物废物的利用将有助于相关食物工业的闭路循环。

Effect of soil pH on the sorption capacity of soil organic matter for polycyclic aromatic hydrocarbons in unsaturated soils

Sorption by soil organic matter(SOM)is considered the most important process affecting the bioavailability of hydrophobic organic chemicals(HOCs)in soil.The sorption capacity of SOM for HOCs is affected by many environmental factors.In this study,we investigated the effects of soil pH and water saturation level on HOC sorption capacity of SOM using batch sorption experiments.Values of soil organic carbon-water partition coefficient(K_(OC))of six selected polycyclic aromatic hydrocarbons(PAHs)were measured in an artificial soil under various soil pH and water saturation conditions.Passive sampling was used to measure K_(OC)with polydimethylsiloxane as the sampling material.Regardless of soil pH,K_(OC)increased with increasing soil water saturation level for lower-molecular-weight PAHs.In contrast,K_(OC)decreased with increasing soil water saturation level for higher-molecular-weight PAHs.Despite some fluctuations,K_(OC)tended to decrease with increasing soil pH at all water saturation levels.This indicates that earlier studies on the effects of soil pH on K_(OC)under saturated conditions could be extended to unsaturated soils.These K_(OC)tendencies were reproduced in three different natural soils,suggesting that the effects of soil water saturation level and pH might be generalized,at least for PAHs.The PAH sorption capacity of SOM was found to be resilient under dynamic soil pH conditions,which can be used to adjust the effects of soil pH.

Carbon and nitrogen dynamics in a Pinus densiflora forest with low and high stand densities

Aims Understanding carbon(C)and nitrogen(N)dynamics and their dependence on the stand density of an even-aged,mature forest provides knowledge that is important for forest management.This study investigated the differences in ecosystem total C and N storage and flux between a low-density stand(LD)and a high-density stand(HD)and examined the effects of stand density on aboveground net primary productivity(ANPP),total belowground C allocation(TBCA)and net ecosystem production(NEP)in a naturally regenerated,65-to 75-year-old Pinus densiflora S.et Z.forest.Methods LD(450 trees ha^(−1))and HD(842 trees ha^(−1))were established in an even-aged,mature P.densiflora forest in September 2006.The forest had been naturally regenerated following harvesting,and the stand density was naturally maintained without any artificial management such as thinning.The diameter at breast height(DBH≥5.0cm)of all live stems within the stands was measured yearly from 2007 to 2011.To compare C and N storage and fluxes in LD and HD,C and N pools in aboveground and belowground biomass,the forest floor,coarse woody debris(CWD)and soil;soil CO_(2) efflux(R_(S));autotrophic respiration(R_(A));litter production;and soil N availability were measured.Further,ANPP,TBCA and NEP were estimated from plot-based measurement data.Important Findings Ecosystem C(Mg C ha^(−1))and N(Mg N ha^(−1))storage was,respectively,173.0±7.3(mean±SE)and 4.69±0.30 for LD and 162±11.8 and 4.08±0.18 for HD.There were no significant differences in C and N storage in the ecosystem components,except for soils,between the two stands.In contrast,there were significant differences in aboveground ANPP and TBCA between the two stands(P<0.05).Litterfall,biomass increment and R_(S) were major C flux components with values of,respectively,3.89,3.74 and 9.07 Mg C ha^(−1) year^(−1) in LD and 3.15,2.94 and 7.06 Mg C ha^(−1) year^(−1) in HD.Biometric-based NEP(Mg C ha^(−1) year^(−1))was 4.18 in LD and 5.50 in HD.Although the even-aged,mature P.densiflora forest had similar C and N allocation patterns,it showed different C and N dynamics depending on stand density.The results of the current study will be useful for elucidating the effects of stand density on C and N storage and fluxes,which are important issues in managing natural mature forest ecosystems.

An Approximation of the Customer Waiting Time for Online Restaurants Owning Delivery System

Online restaurants, which receive online orders and deliver food directly to the customer’s residence, are becoming increasingly popular. To be successful, online restaurants need to provide reliable and prompt deliveries. Careful design of the meal preparation and order delivery systems is needed to avoid excessive cust omer waiting time bet ween ordering and delivery. This paper considers the meal preparation and delivery processes simultaneously to approximate average customer waiting time for deliveries. The authors first discuss the system performance with one cook and unit-capacity delivery vehicles, using an M/G/1queue and a GI/G/1queue. Numerical experiments show that our approximation can adequately describe real waiting times. Then, series queues with multiple cooks and multi-capacity delivery vehicles, e.g., an M/G/n queue and a GI/Gn/1 queue, are examined. Results show that except for situations with a large meal preparation time and a small vehicle capacity, compared with the result of simulation, the approximation in this paper is acceptable with a deviation of less than 20%. The marginal decrease in waiting time associated with hiring more vehicles is est.imated under different meal preparation speeds, sizes of service area and vehicle capacities.

Spatio-temporal change in forest cover and carbon storage considering actual and potential forest cover in South Korea

This study analyzes change in carbon storage by applying forest growth models and final cutting age to actual and potential forest cover for six major tree species in South Korea. Using National Forest Inventory data, the growth models were developed to estimate mean diameter at breast height, tree height, and number of trees for Pinus densiflora, Pinus koraiensis, Pinus rigida, Larix kaempferi, Castanea crenata and Quercus spp. stands. We assumed that actual forest cover in a forest type map will change into potential forest covers according to the Hydrological and Thermal Analogy Groups model. When actual forest cover reaches the final cutting age, forest volume and carbon storage are estimated by changed forest cover and its growth model. Forest volume between 2010 and 2110 would increase from 126.73 to 157.33 m3 hm-2. Our results also show that forest cover, volume, and carbon storage could abruptly change by 2060. This is attributed to the fact that most forests are presumed to reach final cutting age. To avoid such dramatic change, a regeneration and yield control scheme should be prepared and implemented in a way that ensures balance in forest practice and yield.

Response of microbial communities to biochar-amended soils:a critical review

Application of biochar to soils changes soil physicochemical properties and stimulates the activities of soil microorganisms that influence soil quality and plant performance.Studying the response of soil microbial communities to biochar amendments is important for better understanding interactions of biochar with soil,as well as plants.However,the effect of biochar on soil microorganisms has received less attention than its influences on soil physicochemical properties.In this review,the following key questions are discussed:(i)how does biochar affect soil microbial activities,in particular soil carbon(C)mineralization,nutrient cycling,and enzyme activities?(ii)how do microorganisms respond to biochar amendment in contaminated soils?and(iii)what is the role of biochar as a growth promoter for soil microorganisms?Many studies have demonstrated that biochar-soil application enhances the soil microbial biomass with substantial changes in microbial community composition.Biochar amendment changes microbial habitats,directly or indirectly affects microbial metabolic activities,and modifies the soil microbial community in terms of their diversity and abundance.However,chemical properties of biochar,(especially pH and nutrient content),and physical properties such as pore size,pore volume,and specific surface area play significant roles in determining the efficacy of biochar on microbial performance as biochar provides suitable habitats for microorgan-isms.The mode of action of biochar leading to stimulation of microbial activities is complex and is influenced by the nature of biochar as well as soil conditions.

Carbon patterns and processes in East Asian ecosystems:multi-scale approaches

It has been argued that scale is the central problem in ecology(Levin,1992).Studies on carbon cycles and global climate change,the current major themes in modern ecology,require the interfacing of phenomena that occur on different scales of space,time,and ecological organization.For several decades,tremendous efforts have been made to reveal the general patterns of,and the mechanisms for the global carbon cycles.However,many uncertainties remain,particularly on local to regional scales.To reduce these uncertainties,regional collaborations across the board of nations are required.The A3 Foresight Program“Quantifying and predicting terrestrial carbon sinks in East Asia:toward a network of climate change research”,lasting from 2007 to 2012 and supported jointly by the National Natural Science Foundation of China(NSFC),the National Research Foundation of Korea(NRF),and the Japan Society for the Promotion of Science(JSPS),aimed to build a collaborative research and education platform focusing on the carbon processes in terrestrial ecosystems in East Asia.

Arsenic removal from water and soils using pristine and modified biochars

Arsenic(As)is recognized as a persistent and toxic contaminant in the environment that is harmful to humans.Biochar,a porous carbonaceous material with tunable functionality,has been used widely as an adsorbent for remediating As-contaminated water and soils.Several types of pristine and modified biochar are available,and significant efforts have been made toward modifying the surface of biochars to increase their adsorption capacity for As.Adsorption capacity is influenced by multiple factors,including biomass pyrolysis temperature,pH,the presence of dissolved organic carbon,surface charge,and the presence of phosphate,silicate,sulfate,and microbial activity.Improved As adsorption in modified biochars is attributed to several mechanisms including surface complexation/precipitation,ion exchange,oxidation,reduction,electrostatic interactions,and surface functional groups that have a relatively higher affinity for As.Modified biochars show promise for As adsorption;however,further research is required to improve the performance of these materials.For example,modified biochars must be eco-friendly,cost-effective,reliable,efficient,and sustainable to ensure their widespread application for immobilizing As in contaminated water and soils.Conducting relevant research to address these issues relies on a thorough understanding of biochar modifications to date.This study presents an in-depth review of pristine and modified biochars,including their production,physicochemical properties,and As adsorption mechanisms.Furthermore,a comprehensive evaluation of biochar applications is provided in As-contaminated environments as a guide for selecting suitable biochars for As removal in the field.

Integrative assessment of biomarker responses in teleostean fishes exposed to glyphosate-based herbicide(Excel Mera 71)

Present study deals with the effects of glyphosate-based herbicide,Excel Mera 71 on Anabas testudineus,Heteropnestes fossilis and Oreochromis niloticus in field conditions(1.85 kg/ha)based on anti-oxidative,metabolic and digestive responses.For this study following biomarkers viz.,acetylcholinesterase(AChE),lipid peroxidation(LPO),catalase(CAT),glutathione-S-transferase(GST),alkaline phosphatase(ALP),aspartate aminotransferase(AST),alanine aminotransferase(ALT),amylase,lipase and protease were investigated in gill,stomach,intestine,liver,kidney,brain,muscle and spinal cord of the concerned fish species.Enzyme activities were significantly altered by glyphosate exposure after 30 days,these activities were tissue as well as species specific.The results suggested that these biomarkers could be used to assess the ecological risks of glyphosate on fish.Bioaccumulation factor(BAF)studied in different aquatic natural macrophytes showed order of Alternanthera philoxeroides>Azolla pinnata>Lemna sp.(Minor)>Lemna sp.(Major)>Pistia stratiotes,while transfer factor(TF)showed the order of Pistia stratiotes>Alternanthera philoxeroides>Lemna sp.Bioconcentration factor(BCF)study showed maximum accumulation of glyphosate in liver,kidney or intestine,and minimum either in bone or stomach irrespective of fish species.An integrated biomarker response(IBR),which uses a battery of biomarkers to calculate the standardized scores for each biomarker responses ranging from physiological to biochemical/molecular responses,was evaluated by combining the multiple biomarkers into a single value to evaluate quantitatively the toxicological effects of glyphosate.In general,the multiple indices exhibited variations and A.testudineus was more affected than other fish species;maximum IBR value was observed for LPO and minimum in case of ALT.The order of integrated biomarkers caused by glyphosate treatment was recorded as follows:LPO>Amylase>CAT>AST>Protease>Lipase>ALP>GST>AChE>ALT for A.testudineus,LPO>AChE>AST>Protease>CAT>Amylase>Lipase>GST>ALP>ALT for H.fossilis and AChE>CAT>LPO>AST>Amylase>GST>Protease>ALP>Lipase>ALT for O.niloticus.Finally,IBR analysis is able to distinguish the variations between different parameters and might be a useful tool for the quantification of integrated responses induced by glyphosate toward fish.

碳循环研究：东亚生态系统为什么重要

碳循环是地球上最大的生物地球化学循环,它通过植物的光合作用,将大气中的CO2固定为有机质,将太阳能转化成化学能,从而成为人类生产和生活中最基本的物质资料和能量来源.

Why are East Asian ecosystems important for carbon cycle research?

The global carbon cycle is one of the most important biogeochemical cycles. Through photosynthesis, green plants absorb CO2 from the atmosphere to produce organic matters,

利用航空影像和雷达数据估算韩国单株个体赤松林的碳储量

利用航空影像和激光雷达数据,对韩国赤松林的碳储量进行了估算.基于雷达数据建立数字冠层模型,再与航空影像融合,进而划分单株树木的冠幅范围.为消除分段误差,采用高斯滤波方法对融合后的影像进行平滑,然后利用标记控制阈值分割方法提取出单株树木的冠幅范围,再通过建立实测冠幅面积和胸径间的回归方程计算出单株树木的胸径.在此基础上,利用韩国森林研究所建立的回归模型,计算单株树木的地上生物量.单株树木的碳储量由地上生物量乘以转化系数(0.5)得到.结果显示,用此方法估算的平均单株树木碳储量为193.7kgC,与实际测量值223.8kgC较为接近,说明本研究提供的基于航空影像和雷达的方法,可以有效地估算大面积森林树木的生物量和碳储量.