Modelling of matter cycle in a mesotrophic bog ecosystem II. Dynamic model and ecological succession

Based upon the the results of static environ analysis of the organic matter cycle through the ecosystem, a number of dynamic models are developed, in this second part, for the matter and nitrogen cycles. Probable outcomes of ecological succession are obtained within the framework of the dynamic model without using the ergodic hypothesis that is implicitly adopted in ecological studies. The dynamics of both stocks in the ecosytem components and flows among them can be observed within the model in order to compare some turnover characteristics of the succession series with those of the ecological one.     

Life-cycle model of terrestrial carbon exchange

We present here a terrestrial carbon cycle model based on a scheme of the phytomass change, which is continuous in time. The experimental information about net primary production, living and dead phytomass, and soil organic matter for various ecosystems is used for calibration of the model. The suggested model enables to characterize terrestrial ecosystems as carbon sources or carbon sinks and to evaluate intensity of these sources and sinks. The model is applied for the European territory of Russia as a case study. Intensity of the total exchange carbon flux for this territory is evaluated. The obtained results allow to conclude that the given territory is the sink of carbon.     

Evaluating the environmental impacts of an urban wetland park based on emergy accounting and life cycle assessment: A case study in Beijing

In this paper, emergy accounting (EA) and life cycle assessment (LCA) methods are employed to investigate a typical urban wetland park, the Green Lake Urban Wetland Park (GLUWP) of Beijing, in terms of its environmental and capital inputs, ecosystem services and organic matter yields, environmental support, and sustainability. The LCA method is also used to obtain a quantitative estimation of the environmental impact of discharges during the entire life cycle of the GLUWP. Various emergy-based indices, such as emergy yield ratio (EYR), environmental load ratio (ELR), emergy sustainability index (ESI), net economic benefit (Np), and environmental impacts of process-based LCA, including global warming potential (GWP), eutrophication (EU), nonrenewable resource depletion (RU), energy consumption (EN), acidification potential (AP), photochemical oxidant creation potential (POCP), particulate matter (PM) and wastes (W), are calculated. The results show that the GLUWP has higher proportions of renewable resource input, less pressure on the environment, more environmental support and better ecological and economic benefits, which can be considered as an environment-friendly and long-term sustainable ecological practice, compared with another constructed wetland in Beijing. Meanwhile, the dominant environmental impact is induced by POCP with the construction phase contributing the most on the entire life cycle. It is expected that increasing green area, extensively using environment-friendly materials, optimizing construction techniques and reducing power consumption can promote the sustainability of the GLUWP.     

Carbon emission analysis of a residential building in China through life cycle assessment

In this paper, a quantitative life cycle model for carbon emission accounting was developed based on the life cycle assessment (LCA) theory. A residential building in Sino-Singapore Tianjin Eco-city (Tianjin, China) was selected as a sample, which had been constructed according to the concept of green environmental protection and sustainable development. In the scenario of this research, material production, construction, use and maintenance, and demolition phases were assessed by building carbon emission models. Results show that use and maintenance phase and material production phase are the most significant contributors to the life cycle carbon emissions of a building. We also analyzed some factor influences in LCA, including the thickness of the insulating layer and the length of building service life. The analysis suggest that thicker insulating layer does not necessarily produce less carbon emissions in the light of LCA, and if service life of a building increases, its carbon emissions during the whole life cycle will rise as well but its unit carbon emission will decrease inversely. Some advices on controlling carbon emissions from buildings are also provided.     

基于生命周期评价理论的建筑物环境影响评价系统

建筑物对环境有着巨大的影响。基于生命周期评价(LCA)理论,从材料的开采生产,建筑物的建造、运行直至建筑物被拆除来研究建筑物的环境影响。在一个涉及建筑材料、建筑设备以及建设场地的环境影响数据库的基础上,开发了一个建筑物的环境影响的评价模型BEPAS(BuildingEnvironmentalPerformanceAnalysisSystem)。模型从3个方面:建筑设备运行、建筑材料和建筑场地来研究建筑的环境影响。最后,测算了一个案例,分析了其环境影响水平。     

A Functional Approach to the Assessment of the Nutritional Value of Particulate Organic Matter

Organic matter lability can be determined with different approaches, based on the quantitative and qualitative estimate of its nutritional value. the C/N ratio and the particulate organic matter (as the sum of protein, carbohydrate and lipid bulks) vs total suspended matter (POM/TSM) deal with a quantitative assessment of the organic matter bulk, while other indices such as proteins/carbohydrates ratio (PRT/CHO) may give also qualitative information. Gordon (1970) proposed a functional approach, based on organic carbon decrease after enzymatic digestion. Coupling Gordon's approach with the evaluation of the main biochemical components (proteins, carbohydrates and lipids) contained in the particulate organic matter, a simple method to assess lability and nutritional value of organic substrates is proposed.

Water samples were collected at the surface and close to the bottom in a shallow coastal station (10 m depth) in the Marconi Gulf (Ligurian Sea, NW Mediterranean). the difference between “total labile” and “hydrolyzed labile” organic matter (respectively before and after enzymatic digestion) suggests a relevant presence of resuspended refractory materials vs about 60% of labile hydrolyzed organic matter, thus confirming the importance of a more qualitative approach to organic matter studies.     

草地枯落物分解研究进展及展望

草地枯落物是草地生态系统中生物组分枯死后所有有机物质的总称,是草地生态系统重要的组成部分,是除冠层外,大气与矿质土壤层、植物根系层进行物质与能量交换的另一介质,在生态学中起着不可替代的作用。随着西部大开发战略和退耕还林还草工程的实施,大型家畜等草食性动物退出草地生态系统后,枯落物成为草地生态系统物质和能量循环的重要调节枢纽。近年来,随着全球应对气候变化、节能减排和低碳经济所面临的压力,作为全球碳循环的重要组成部分,草地枯落物的研究被越来越多的学者所重视。文章在综述国内外大量文献的基础上,对草地枯落物的概念进行了比较分析,对其进行了准确定义;归纳出了尼龙网袋法、室内分解培养法、现量估算法和同位素法等多种草地枯落物分解方法,并就枯落物分解过程中经常采用的分解率概算模型、时间衰减模型、影响因子关系模型等进行了比较分析,总结出枯落物的分解是由淋溶、自然粉碎和代谢等3个主要作用,碎屑食物链、腐食食物链等2种不同的食物链共同组成的复杂过程。开展长期定位监测、形成统一的研究方法,探索枯落物分解过程中碳循环微观机理,以及影响因子之间的交互作用是未来草地枯落物研究工作的重点。     

Dynamic compartment approach for modelling regimes of carbon cycle functioning in bog ecosystems

Svirezhev's method of dynamic model design by a given “storage-flow” diagram [Svirezhev Y.M., 1997. On some general properties of trophic networks. Ecol. Model. 99, 7–17] is developed and used for investigating dynamic regimes of carbon cycle functioning in a typical boreal transitional bog ecosystem. Ecosystems are often represented by static “storage-flow” diagrams reflecting their structure and matter or energy transfer between components at fixed time moments. Using the data of such diagrams aggregated in ecological field studies one can construct a dynamic model of the ecosystem to predict its future behaviour and to estimate a response to external perturbations—natural and human. Stability of both current equilibrium and possible alternative steady states and more complicated attractors are studied under two types of parameter perturbation: CO₂ atmospheric concentration increase initiated by greenhouse effect, and change in the rate of carbon output from dead organic matter and litter which depends on the water table level and possible peat excavation. Calculation of bifurcation curves gives areas in the parameter space where stable functioning of carbon cycle is provided. Steady states can be interpreted as raised bog, meadow, forest and fen. CO₂ concentration increase leads the current state of transitional bog to loose stability with appearance of oscillatory dynamics and further evolution to the chaotic attractor. The model is rich by chaotic solutions serving as transition regimes between regular steady and periodic attractors. Another chaotic regime is formed from forest equilibrium and exists in the same area of phase space where current equilibrium is stable.     

Trend,seasonal variation and sources of suspended particulated matter (SPM) in Spain

In this study we analyze the temporal evolution of the suspended particulated matter (SPM) in the air of the six Spanish remote stations belonging to the European Monitoring and Evaluation Programme network. A negative trend is observed in three of them and a positive trend in one. Another objective of this work was to know the geographical sources of SPM in Spain. To do this we used the conditional probability functions (cf. Ashbaugh et al. (1985), Atmos. Environ., 19, 1263–1270) and information about air masses trajectories. The North of Africa and regions inside Spain are the main sources while Continental Europe and the British Islands are less important.     

Modelling the components of the vertical attenuation of ultraviolet radiation in a wetland lake ecosystem

The extinction of solar UV (290–400 nm) radiation in aquatic ecosystems is a complex phenomena. In this paper, we examine and model the attenuation of UV radiation in a shallow lake ecosystem. In particular we focus our analysis on the specific role of the fractions of dissolved and particulate matter in the water column in the attenuation of radiation. This analysis is aimed by representing the spatial distribution of each fraction making it possible to evidence the spatial variation in habitat quality. In situ and laboratory measurement are used to elaborate a UV attenuation model. The attenuation model distinguishes between the contribution of particulate and dissolved matter in the attenuation of the solar UV flux. In the studied wetland lake (Laguna Iberá, sub-tropical latitude, Argentina) the importance of dissolved matter is dominated in the UVB solar spectrum (290–320 nm) but the effects of the particulate fraction are not negligible, in particular in UVA (320–400 nm). The spatial representation of model results demonstrate the non homogeneous nature between attenuation of the two fractions. Local and global environmental change can have important impacts on dissolved and particulate matter concentrations, which cam have ecological consequences in relation to the high flux of incoming UV radiation. The model developed to examine the relative attenuation of the dissolved and particulate fractions and is a useful instrument to identify the role that these fractions have on the optical characteristics of aquatic ecosystems.     

Analysis of periodic patterns of daily precipitation through simultaneous modeling of its serially observed occurrence and amount

Precipitation is of great importance to agriculture, environment and ecosystem as a regular precipitation pattern is usually vital to healthy plants; excessive or insufficient rainfall can be harmful. Periodic patterns of precipitation can be studied based on regularly observed data over time. Since regularly observed precipitation data are generally skewed with many zeros, two common analysis approaches have been proposed recently. One approach investigates precipitation using a two-part model where the occurrence and positive amount of precipitation are analyzed separately (Piantadosi et al. in Environ Model Assess 14:431–438, 2009), whereas the other approach handles occurrence and amount simultaneously using a Tweedie’s compound Poisson model for independent observations (Hasan and Dunn in Int J Climatol 32:1006–1017, 2012). The former approach fails to maintain the regular temporal structure of serially observed precipitation, whereas the latter approach ignores serial dependence. As there is generally substantial serial correlation in the observed sequence of precipitation data over time, we introduce a compound Poisson state-space model with serially correlated random effects for daily precipitation data. This approach characterizes both occurrence and amount of precipitation simultaneously while accounting for the corresponding serial correlation. Our main results depend only on the first- and second-moment assumptions of unobserved random effects. We illustrate our method with the analysis of the daily precipitation data recorded at Mount Washington, NH, USA.     

Reply to the EFSA (2016) on the relevance of recent publications (Hofmann et al. 2014, 2016) on environmental risk assessment and management of Bt-maize events (MON810, Bt11 and 1507)

In this commentary, we respond to a report of the EFSA GMO Panel (EFSA EFSA Supp Publ, 1) that criticises the outcomes of two studies published in this journal (Hofmann et al. Environ Sci Eur 26: 24, 2; Environ Sci Eur 28: 14, 3). Both publications relate to the environmental risk assessment and management of Bt-maize, including maize events MON810, Bt11 and maize 1507. The results of Hofmann et al. (Environ Sci Eur 26: 24, 2), using standardised pollen mass filter deposition measurements, indicated that the EFSA Panel model had underestimated pollen deposition and, hence, exposure of non-target organisms to Bt-maize pollen. The results implied a need for safety buffer distances in the kilometre range for protected nature reserve areas instead of the 20–30 m range recommended by the EFSA Panel. As a result, the EFSA Panel revised their model (EFSA EFSA J 13: 4127, 4), adopting the slope of the empirical data from Hofmann et al. The intercept, however, was substantially reduced to less than 1% at one point by introducing further assumptions based on the estimates of mainly panel members, citing possible ‘uncertainty’. Hofmann et al. (Environ Sci Eur 28: 14, 3) published extensive empirical data regarding pollen deposition on leaves. These results were part of a larger 3-year study involving detailed measurements of pollen release, dispersal and deposition over the maize flowering period. The data collected in situ confirmed the previous predictions of Hofmann et al. (Environ Sci Eur 26: 24, 2). Mean levels and observed variability of pollen deposition on maize and four lepidopteran host plants exceeded the assumptions and disagreed with the conclusions of the EFSA Panel. The EFSA Panel reacted in a report (EFSA EFSA Supp Publ, 1) criticising the methods and outcomes of the two published studies of Hofmann et al. while reaffirming their original recommendations. We respond here point-by-point, showing that the critique is not justified. Based on our results on Urtica leaf pollen density, we confirm the need for specific environmental impact assessments for Bt-maize cultivation with respect to protected habitats within isolation buffer distances in the kilometre range.     

Identification and assessment of environmental burdens of Chinese copper production from a life cycle perspective

The environmental burdens of Chinese copper production have been identified and quantified in the context of typical technologies, materials supplies and environmental emissions by a life cycle approach. Primary and secondary copper production using copper ores and scraps, respectively, were analyzed in detail. The flash and bath smelting approaches and the recycling of copper scraps were selected as representative copper production processes. A quantitative analysis was also conducted to assess the influence of material transport distance in copper production. Life cycle assessment （LCA） results showed that resources depletion and human health contribute significantly to environmental burdens in Chinese copper production. In addition, the secondary copper production has dramatically lower environmental burdens than the primary production. There is no obvious distinction in overall environmental burdens in primary copper production by flash or bath smelting approach. However, resources depletion is lower and the damage to human health is higher for flash smelting approach. Ecosystem quality damage is slight for both approaches. Environ- mental burdens from the mining stage contribute most in all life cycle stages in primary copper production. In secondary copper production, the electrolytic refining stage dominates. Based on the life cycle assessment results, some suggestions for improving environmental performance were proposed to meet the sustainable development of Chinese copper industry.     

Modelling cyanobacteria in shallow coastal seas

There is an increasing need to describe cyanobacteria bloom dynamics using ecosystem models. We consider two fundamentally different ways how cyanobacteria are currently implemented: a simple approach without explicit consideration of the life cycle which assumes that cyanobacteria grow due to nitrogen fixation alone and an advanced approach that computes the succession of four different stages of the cyanobacteria life cycle based on internal quotas of energy and nitrogen. To qualitatively and quantitatively intercompare these different approaches and with observations, we use the Baltic Sea ecosystem model ERGOM coupled to the one-dimensional water column model GOTM. Four experiments are carried out: three, using the simple approach with either (a) a prescribed constant minimum production, (b) no minimum value or (c) a prescribed constant minimum concentration, and one with (d) the full predictive life cycle. The model data of 35 years (1970-2005) are analyzed for the timing of the bloom, the interannual variability, the annual mean nitrogen fixation rates and the effect of cyanobacteria on eukaryotic phytoplankton. The results show significant differences. In the climatological seasonal mean, only the advanced approach which resolves the life cycle produces a realistic bloom onset and duration. The interannual variability of blooms is unrealistically small in the experiments with a prescribed minimum value. Annual mean nitrogen fixation rates diverge by up to 30% between the four model solutions. Finally, the representation of the cyanobacteria also influences the seasonal cycle of eukaryotic phytoplankton, i.e., flagellates. This study demonstrates that the way how cyanobacteria are implemented in coupled biological-physical models strongly determines the fluxes into the system and between the individual compartments.     

Modeling the supply of wastepaper

Utilizing a price expectations model of wastepaper supplies Edwards [J. Environ. Econ. Manag.6, 332–334 (1979)] claims to be able to explain certain anomalies in earlier empirical work while reaffirming the view that wastepaper supply is generally price inelastic. This paper presents evidence to show that the price expectations model does not offer an adequate explanation of the state of affairs in the U.K. wastepaper market. The low price elasticity of supply findings are, however, confirmed.     

Interferences of carbonate quantification in municipal solid waste incinerator bottom ash: evaluation of different methods

Quantification of carbonate contents in fresh and weathered municipal solid waste incinerator (MSWI) bottom ash was performed using volumetric and gravimetric methods, Fourier Transform Infrared (FT-IR) spectroscopy and thermal analysis. Results differ considerably depending on the method applied. Volumetric measurement and thermogravimetry (TG) are based on the determination of CO₂ release by acid or thermal treatment, respectively. Interactions of CO₂ with the mineral matrix and de novo synthesis of carbonates during thermal analysis were observed. In order to find out the contribution of CO₂ released from residual organic matter, an additional experiment was carried out to demonstrate how the material is affected by the heating process in the course of thermal analysis. FT-IR spectroscopy as a non-destructive method seems to provide the most reliable quantitative results.     

Sensitivity analysis with a phosphorus diagenesis model (SPIEL)

Sensitivity analysis is an important part of the modelling procedure. In this paper, sensitivity analysis of a phosphorus diagenesis model (SPIEL) was used for determining the most important parameters and forcing functions, as well as the potential influence of technical in-lake measures on phosphorus (P) release from the sediment. The model “Sedimentary Phosphorus In Eutrophic Lakes” (SPIEL) includes sub-modules for calculating the aerobic layer thickness, the iron–sulphur cycle and the free aluminium sorption capacity. The results of a detailed sensitivity analysis for different module combinations were compared. By means of graphical representation of the cause and effect chains, the synergistic and compensatory effects of different processes on P release in Lake Sempach were discussed. The importance of the iron–sulphur cycle and of the aerobic layer thickness for the P release in this lake is demonstrated.