Nitrogen and Phosphorus in the Finnish Energy System, 1900–2003

In producing power, humans move the nutrients nitrogen (N) and phosphorus (P) from their long‐term geological and biological stocks and release or emit them in soil, water, and the atmosphere. In Finland, peat combustion is an important driver of N and P fluxes from the environment to human economy. The flows of N and P in the Finnish energy system were quantified with partial substance flow analysis, and the driving forces of emissions of nitrogen oxides (NOx) were analyzed using the ImPACT model. In the year 2000 in Finland, 140,000 tonnes of nitrogen entered the energy system, mainly in peat and hard coal. Combustion released an estimated 66,000 tonnes of N as nitrogen oxides (NOx) and nitrous oxides (N2O) and another 74,000 tonnes as elemental N2. Most of the emissions were borne in traffic. At the same time, 6,000 tonnes of P was estimated to enter the Finnish energy system, mostly in peat and wood. Ash was mainly used in earth construction and disposed in landfills; thus negligible levels of P were recycled back to nature. During the twentieth century, fuel‐borne input of N increased 20‐fold, and of P 8‐fold. In 1900–1950, the increasing use of hard coal slowly boosted N input, whereas wood fuels were the main carrier of P. Since 1970, the fluxes have been on the rise. NOx emissions leveled off in the 1980s, though, and then declined in conjunction with improvements in combustion technologies such as NOx removal (de‐NOx) technologies in energy production and catalytic converters in cars.     

Estimation of Tissue Construction Cost from Heat of Combustion and Organic Nitrogen Content

Abstract. We present a method for estimating the construction costs of plant tissues from measurements of heat of combustion, ash content, and organic nitrogen content. The method predicts glucose equivalents, the amount of glucose required to provide carbon skeletons and reductant to synthesize a quantity of organic product. Glucose equivalents have previously been calculated from the elemental composition of tissue. We define construction cost as the amount of glucose required to provide carbon skeletons, reductant and ATP for synthesizing the organic compounds in a tissue via standard biochemical pathways. The fraction of the total construction cost of a compound or tissue (excluding costs of transporting compounds) that is reflected in its glucose equivalents is the biosynthetic efficiency ( E _B). This quantity varies between 0.84 and 0.95 for tissues with a wide range of compositions. Using the new method, total construction cost can be estimated to ± 6% of the value obtained from biochemical pathway analysis.
Construction costs of leaves of three chaparral species were estimated using the proposed method and compared to previously published values, derived using different methods. Agreement among methods was generally good. Differences were probably due to a combination of inaccuracy in the estimated biosynthetic efficiency and technical difficulties with biochemical analysis, one of the older methods of determining construction cost.     

Effect of simulated forest fire on the availability of N and P in mediterranean soils

The effect of soil burning on N and P availability and on mineralization and nitrification rates of N in the burned mineral soil was studied by combustion of soils in the laboratory. At a fire temperature of 600°C, there was a complete volatilization of NH₄ and a significant increase of pH, from 7.6 in the unburned soil to 11.7 in the burned soil. Under such conditions ammonification and nitrification reactions were inhibited. Less available P was produced immediately after the fire at 600°C, as compared to P amount produced at 250°C. Burning the soils with plants caused a decrease in NH₄-N and (NO₂+NO₃)-N concentrations in the soil as well as a reduction in ammonification and nitrification rates. Combustion of soil with plants contributed additional available P to the burned soil. The existence of a non-burned soil under the burned one played an important role in triggering ammonification and nitrification reactions.     

An alternate method of calculating the heat of growth of Escherichia coli K-12 on succinic acid

The DeltaH(f) (0) unit weight of a complex substance such as a biological macromolecule is almost always obtained by means of combustion analysis. In theory, this can also be done by summing the DeltaH(f) (0) values for the monomers comprising the macromolecule plus the enthalpic energies involved in their polymerization. The enthalpy of formation of one unit-carbon formula weight of dried Escherichia coli K-12 cells was determined by summing the values of the enthalpies of formation of the quantities of monomers in the major classes of macromolecules substances comprising the cellular biomass and the enthalpic energies involved in their polymerizations. To this value was added the enthalpy of formation of the cellular ions in their aqueous standard states, per unit-carbon formula weight of cellular substance and the enthalpy change with respect to the ionization of the protein amino acid side chains. If it is assumed that the cellular fabric is insoluble and that the ions are soluble, the sum of the enthalpies of formation of all the cellular components should closely approximate the enthalpy of formation of one unit-carbon formula weight equivalent of living cells. Using this value, a calculation of the enthalpy change accompanying anabolism shows this latter to be effectively zero, indicating that the heat of growth (anabolism plus catabolism) is equal to that calculated for catabolism alone. This conclusion is in accord with those of several investigators who have used manometry or direct calorimetry.     

模拟地表火行为对燃烧剩余物水溶性碳氮的影响

燃烧剩余物是火烧迹地土壤表面必然存在的残留物,可以通过降水过程以及地表径流释放其所含有的矿物质和有机质至土壤生态系统,从而在一定时间内持续地对火后生态系统恢复过程造成影响。但不同火行为下,相同的可燃物所产生的燃烧剩余物可能具有不同的生态学功能,为了认知火行为对燃烧剩余物的影响,进一步了解二者对火烧迹地生态恢复过程中养分循环和能量流动的潜在影响,探究了火行为对燃烧剩余物水溶性碳氮化学计量特征的影响。以红松人工林地表可燃物为实验材料,通过设置不同坡度和含水率为火行为的驱动因子,进行了森林可燃物床层地表上坡火和下坡火的室内模拟燃烧实验。用独立样本T检验、单因素方差分析、多因素方差分析探究了火环境对燃烧剩余物水溶性碳氮和火行为的影响,用基于距离的冗余分析(db-RDA)探究了火行为对燃烧剩余物水溶性碳氮化学计量特征的影响。上坡火实验组的燃烧剩余物水溶性碳氮含量明显高于下坡火实验组(P<0.01);5°实验组中,燃烧剩余物的水溶性碳含量随着可燃物预设含水率的升高而升高(P<0.05)。进一步的数据分析发现火行为与燃烧剩余物水溶性碳氮化学计量特征关系密切,火焰宽度是影响燃烧剩余物水溶性...     

江西九连山常绿阔叶林主要树种叶建成消耗的比较

叶建成消耗（或叶构建消耗）是指构建单位质量（面积）叶片所需要的葡萄糖当量,是植物碳收获过程中必要的成本投资．反映植物在叶片水平上的能量和碳分配策略。基于热值、灰份含量、叶氮含量和比叶面积的测定,估算了江西九连山常绿阔叶林16个主要树种的叶建成消耗,分析比较了不同树种、不同叶寿命、比叶面积和冠层不同部位对叶建成消耗的影响。结果表明,热值组分的变化对单位质量叶建成消耗的影响最大;树种间单位质量叶建成消耗的差异不大（变化率仅3％～6％）,但其单位面积叶建成消耗则存在显著差异（变化率达27％～28％）;热值和单位质量叶建成消耗与比叶面积密切相关,而比叶面积随取样高度呈显著的降低趋势,最终导致热值及单位质量和单位面积的叶建成消耗均随取样高度呈显著的增加趋势。研究结果指出：（1）较高的叶建成消耗是由于植物叶片内含有较高能量投资的化学组分;（2）叶建成消耗和比叶面积随取样高度的变化综合反映了植物对光照和水分资源垂直梯度变化的可塑性适应。     

Nitrogen Cycles: Past, Present, and Future

This paper contrasts the natural and anthropogenic controls on the conversion of unreactive N₂ to more reactive forms of nitrogen (Nr). A variety of data sets are used to construct global N budgets for 1860 and the early 1990s and to make projections for the global N budget in 2050. Regional N budgets for Asia, North America, and other major regions for the early 1990s, as well as the marine N budget, are presented to Highlight the dominant fluxes of nitrogen in each region. Important findings are that human activities increasingly dominate the N budget at the global and at most regional scales, the terrestrial and open ocean N budgets are essentially disconnected, and the fixed forms of N are accumulating in most environmental reservoirs. The largest uncertainties in our understanding of the N budget at most scales are the rates of natural biological nitrogen fixation, the amount of Nr storage in most environmental reservoirs, and the production rates of N₂ by denitrification.     

Bioavailability and potential carcinogenicity of polycyclic aromatic hydrocarbons from wood combustion particulate matter in vitro

Due to increasing energy demand and limited fossil fuels, renewable energy sources have gained in importance. Particulate matter (PM) in general, but also PM from the combustion of wood is known to exert adverse health effects in human. These are often related to specific toxic compounds adsorbed to the PM surface, such as polycyclic aromatic hydrocarbons (PAH), of which some are known human carcinogens. This study focused on the bioavailability of PAHs and on the tumor initiation potential of wood combustion PM, using the PAH CALUX® reporter gene assay and the BALB/c 3T3 cell transformation assay, respectively. For this, both cell assays were exposed to PM and their respective organic extracts from varying degrees of combustion. The PAH CALUX® experiments demonstrated a concentration–response relationship matching the PAHs detected in the samples. Contrary to expectations, PM samples from complete (CC) and incomplete combustion (IC) provided for a stronger and weaker response, respectively, suggesting that PAH were more readily bioavailable in PM from CC. These findings were corroborated via PAH spiking experiments indicating that IC PM contains organic components that strongly adsorb PAH thereby reducing their bioavailability. The results obtained with organic extracts in the cell transformation assay presented the highest potential for carcinogenicity in samples with high PAH contents, albeit PM from CC also demonstrated a carcinogenic potential. In conclusion, the in vitro assays employed emphasize that CC produces PM with low PAH content however with a general higher bioavailability and thus with a nearly similar carcinogenic potential than IC PM.     

The effect of harvest date and harvest method on the combustion characteristics of Miscanthus × giganteus

Miscanthus × giganteus is an energy crop with many attributes that make it a potential biofuel feedstock. This study examined the chemical composition of M. × giganteus stems cut at different dates throughout the spring harvest window (January, February and March) and either left in a swath or left flat in a thin layer on the ground and compared the composition to that of the standing crop collected on the same date in April (control). The research then examined the effect of cutting date on the chemical composition of whole plant M. × giganteus biomass (leaf and stem). The parameters examined in both parts of this experiment were lower heating value on a wet basis (LHV_WB), ash, chlorine, potassium, nitrogen, sulphur, carbon and hydrogen content. The range of values recorded for the parameters from both aspects of this trial were LHV_WB 4.84–11.87 MJ kg^?1; ash 1.44–1.97%; Cl 0.07–0.23%; K 0.15–0.32%; N 0.28–0.39%; S 0.13–0.19%; C 46.75–50.00%; H 5.76–6.09%. The length of time that the M. × giganteus remained in the field after cutting affected the LHV_WB (increased with time) of the stem biomass material. Cutting the biomass and leaving it in the field lowered the ash, Cl and C content of the stem material compared to that of the control which was cut and collected on the same date. No differences were observed for the other parameters. Date of harvest affected the LHV_WB, Cl and C content which all improved with later cutting dates. Thus, combustion quality can be improved by delaying the harvest date or by cutting the crop and leaving it in the field for a period prior to collection. Choosing the correct combination of time and harvest method can therefore improve biomass fuel quality.     

Menez-Dregan 1 (Plouhinec,Finistère,France) : un site d’habitat du Paléolithique inférieur en grotte marine. Stratigraphie,structures de combustion,industries riches en galets aménagés

The Lower Palaeolithic site of Menez-Dregan I is currently the subject of an important excavation and has been part of a multidisciplinary project since 1991. It is an ancient marine cave whose roof has gradually collapsed and thus partly protected the site from erosion. In Menez-Dregan 1, the sedimentological evidence has been significantly reduced due to multiple episodes of marine erosion in the cave (low sedimentary preservation in terms of sedimentation and erosion process). However, the proximity of a section with a longer sedimentary record (Gwendrez cliff) has allowed for an attempt at correlation between the different deposits by way of a sedimentologic study applied to sandy marker beds (dunes). The resulting new data permitted a more precise chronostratigraphy of this site to be drawn up and contributed to further validation of dating. Three main stratigraphic units show distinct levels of human occupation at the site, separated by coastal deposits. The ESR dates tend to place the first human occupation in MIS 12 or at the end of MIS 13 (around 465,000 years). The ESR dating obtained at the base of layer 5 gave an age of 380,000 years. The geological analysis (sedimentology, stratigraphical correlations at short distance) tends to confirm these dates. The fauna has not preserved due to the acidic environment, leaving only the lithic industry to show how the human groups who settled at the site lived and, it is worth noting, mastered fire lighting, and or control, at a very early date (late MIS 13 or early MIS 12). The lithic industry from the upper levels (layer 5) is likely Colombanian and is composed of numerous flakes and cores alongside a great quantity of cobble tools (mostly choppers), fractured cobbles, and cobbles with isolated removals on various types of rocks, some cleavers and very rare bifaces. Additionally denticulates and notches form the main part of the light duty tools, together with scrapers. These retouched light duty tools are mainly made on flint, but quartz and glossy sandstone were also used. The last level of occupation (layer 4) probably shows the transition between Lower and Middle Palaeolithic. This may represent a regional cobble tool industry of the south armorican shoreline, however, it is still difficult to separate it totally from the classic European Acheulean from Northern France. These armorican lithic industries could indeed correspond with areas of specialised activities, as demonstrated for some Middle Palaeolithic groups with a cobble tools lithic industry. The notion of culture that could be chosen to explain this variability must be treated with caution, because it would only be based on the presence or absence of only one type of tool (the handaxe).