• Energy Research
• Restricted close
• 15. Life on land close
• 2. Zero hunger close
• DK close
• IN close

The oleaginous alga Chlorella protothecoides accumulates lipid in its biomass when grown in nitrogen-restricted conditions. To assess the relationship between nitrogen provision and lipid accumulation and to determine the contribution of photosynthesis in mixotrophic growth, C. protothecoides was grown in mixo- and heterotrophic nitrogen-limited continuous flow cultures. Lipid content increased with decreasing C/N, while biomass yield on glucose was not affected. Continuous production of high lipid levels (57% of biomass) was possible at high C/N (87-94). However, the lipid production rate (2.48 g L(-1) d(-1)) was higher at D=0.84 d(-1) with C/N 37 than at D=0.44 d(-1) and C/N 87 even though the lipid content of the biomass was lower (38%). Photosynthesis contributed to biomass and lipid production in mixotrophic conditions, resulting in 13-38% reduction in CO2 production compared with heterotrophic cultures, demonstrating that photo- and heterotrophic growth occurred simultaneously in the same population.

Abstract Nitrous oxide (N2O) is an important long-lived greenhouse gas and precursor of stratospheric ozone-depleting mono-nitrogen oxides. The atmospheric concentration of N2O is persistently increasing; however, large uncertainties are associated with the distinct source strengths. Here we investigate for the first time N2O emission from terrestrial vegetation in response to natural solar ultra violet radiation. We conducted field site measurements to investigate N2O atmosphere exchange from grass vegetation exposed to solar irradiance with and without UV-screening. Further laboratory tests were conducted with a range of species to study the controls and possible loci of UV-induced N2O emission from plants. Plants released N2O in response to natural sunlight at rates of c. 20–50 nmol m−2 h−1, mostly due to the UV component. The emission response to UV-A is of the same magnitude as that to UV-B. Therefore, UV-A is more important than UV-B given the natural UV-spectrum at Earth's surface. Plants also emitted N2O in darkness, although at reduced rates. The emission rate is temperature dependent with a rather high activation energy indicative for an abiotic process. The prevailing zone for the N2O formation appears to be at the very surface of leaves. However, only c. 26% of the UV-induced N2O appears to originate from plant-N. Further, the process is dependent on atmospheric oxygen concentration. Our work demonstrates that ecosystem emission of the important greenhouse gas, N2O, may be up to c. 30% higher than hitherto assumed.

The morphological responses of seedlings of eight African provenances of Vitellaria paradoxa (Shea tree or Karite) to imposed draught stress were compared under nursery experimental conditions. The potted seedlings were subjected to three different watering regimes (87 days after sowing): no water stress (100% of the field capacity, C), moderate water stress (75% of C) and severe water stress (50% of C). Before the application of the stress, we observed genotypical differences in the morphological variables at the scale of leaves and of above-ground parts. The six-month water stress affected aerial growth: all provenances responded to drought by down-regulating growth (in height and in diameter), leaf number and area. Katawki provenance of Uganda performed relatively poorly, possibly of it being a nilotica subspecies, contrary to the others (paradoxa subspecies). There was a lack of correlation between climate of seeds origin, seed characteristics, seeds germination and survival rate of seedlings. The study confirmed the importance of leaf area in the vigor of the initial growth in this species. Thus, Tamale and Karaba provenances performed better than other West African provenances due to their larger leaf area, which was found to be a determining factor of relative growth in height at the seedling stage.

Selection of sheep with low enteric methane (CH4) emissions is a greenhouse gas (GHG) mitigation option suitable for pastoral systems. However, the effect of breeding sheep with low enteric CH4 emissions on excreta output and associated CH4 and nitrous oxide (N2O) emissions and therefore total GHG emissions are not known. The objective of the current experiments were to determine excreta output, and estimate associated GHG emissions, from progeny of low and high enteric CH4 per unit of dry matter intake (DMI) selection line sheep (CH4/DMI). The animals were fed two qualities of cut perennial ryegrass-based pasture (very mature vs. vegetative, 12 animals per CH4/DMI line) in Exp. 1 and cut pasture in two repeated seasons (autumn and winter; 15 animals per CH4/DMI line × 2 seasons) in Exp. 2. Total faecal and urine output was determined on individual animals, followed by enteric CH4 emission measurements in respiration chambers. GHG emissions from urine (N2O) and faeces (CH4 and N2O) were estimated based on New Zealand Agricultural GHG Inventory methodology. There was no interaction between CH4/DMI selection line and diet quality in Exp. 1 or seasons in Exp.2. Total daily faecal output of DM, organic matter (OM) and neutral detergent fibre (NDF; all g/d) and associated calculated faecal CH4 emissions were greater for low compared to high CH4/DMI sheep in Exp. 1 (P 4/DMI selection lines in Exp. 2. Nitrogen (N) excretion and N partitioning into urine, faeces and body retention, and calculated excreta N emissions, were mostly similar between CH4/DMI selection line sheep in both experiments. Except, faecal N output (g/d and per unit of N intake) and associated calculated direct faecal N2O-N emissions (g/d) were greater in low compared to high CH4/DMI sheep in Exp. 1 (P 4 emissions were numerically 8% less (P = 0.15) in Exp.1 and 10% less (P = 0.004) in Exp. 2 and total animal level GHG emissions (CH4 and N2O) were numerically 7% less (P = 0.21) in Exp. 1 and 8% less (P = 0.006) in Exp.2 for progeny of the low compared to the high CH4/DMI line sheep. In conclusion, the magnitude of difference in enteric CH4 (expressed as CO2-equivalent) between low and high CH4/DMI selection line sheep were still present when CH4 from faeces and N2O emissions from urine and faeces were also accounted for. The animal genetic traits were expressed independent of environmental factors, i.e. pasture quality and season.

Wheat straw is an abundant agricultural residue with low commercial value. An attractive alternative is utilization of wheat straw for bioethanol production. However, production costs based on the current technology are still too high, preventing commercialization of the process. In recent years, progress has been made in developing more effective pretreatment and hydrolysis processes leading to higher yield of sugars. The focus of this paper is to review the most recent advances in pretreatment, hydrolysis and fermentation of wheat straw. Based on the type of pretreatment method applied, a sugar yield of 74-99.6% of maximum theoretical was achieved after enzymatic hydrolysis of wheat straw. Various bacteria, yeasts and fungi have been investigated with the ethanol yield ranging from 65% to 99% of theoretical value. So far, the best results with respect to ethanol yield, final ethanol concentration and productivity were obtained with the native non-adapted Saccharomyses cerevisiae. Some recombinant bacteria and yeasts have shown promising results and are being considered for commercial scale-up. Wheat straw biorefinery could be the near-term solution for clean, efficient and economically-feasible production of bioethanol as well as high value-added products.

To have all-year-round available feedstock, whole-crop maize is harvested premature, when it still contains enough moisture for the anaerobic ensiling process. Silage preparation is a well-known procedure for preserving plant material. At first, this method was applied to obtain high-quality animal feed. However, it was found that such ensiled crops are very suitable for bioenergy production. Maize silage, which consists of hardly degradable lignocellulosic material, hemicellulosic material, and starch, was evaluated for its potential as a feedstock in the production of bioethanol. It was pretreated at low severity (185 degrees C, 15 min) giving very high glucan ( approximately 100%) and hemicellulose recoveries (<80%)-as well as very high ethanol yield in simultaneous saccharification and fermentation experiments (98% of the theoretical production based on available glucan in the medium). The theoretical ethanol production of maize silage pretreated at 185 degrees C for 15 min without oxygen or catalyst was 392 kg ethanol per ton of dry maize silage.

Background, Aim and Scope Soybean meal is an important protein input to the European livestock production, with Argentina being an important supplier. The area cultivated with soybeans is still increasing globally, and so are the number of LCAs where the production of soybean meal forms part of the product chain. In recent years there has been increasing focus on how soybean production affects the environment. The purpose of the study was to estimate the environmental consequences of soybean meal consumption using a consequential LCA approach. The functional unit is ‘one kg of soybean meal produced in Argentina and delivered to Rotterdam Harbor’.

Based on the approach of 'arena of development' controversies over bioenergy in the shaping of a Danish climate strategy are analyzed as a contribution to a sustainable transition perspective on bioenergy in industrialized societies with substantial agricultural production. Bioenergy plays a prominent role in several Danish climate and energy plans, alongside with wind and solar energy, and energy savings. There are major controversies about targets for bioenergy with respect to acceptable types, sources and amounts of biomass. Strong path dependency is identified. Energy companies in Denmark convert coal fired power plants to biomass in order to sustain the role of these power plants. Their increasing use of imported wood pellets is criticized for increasing greenhouse gas emissions because of fast logging of years of forest growth. A Danish biotech company is developing enzymes for processing of biomass for biofuels. The alignment with the private car regime is strong, because biofuel enables continuation of fuel-driven vehicles as dominating transportation mode. Danish farmers see manure as important source for biogas while arguing for reduction of climate impact and nuisances from digested manure. Such biogas is questioned by some NGOs who fear manure-based biogas is used as argument for increased animal husbandry. The bioenergy controversies concern also methodologies for environmental assessments, including for indirect land use changes (ILUC), and reliability of certification schemes. The mapping of controversies identifies issues that probably need to be taken into account in shaping of Danish bioenergy strategies if these strategies should gain substantial legitimacy among environmental NGOs.

Specialization can become detrimental to a discipline if it fosters intellectual isolation. A bibliographic analysis of several research areas in plant ecology (invasion biology, succession ecology, gap/patch dynamics, and global change effects on plants) revealed that plant ecologists do not regularly make use of the findings and insights of very similar studies being conducted in other research subdisciplines, nor do they try to make their findings and insights easily accessible to researchers in other areas. Invasion papers were least likely to be cross-linked (6%) with other fields, whereas gap/patch dynamics papers were most likely to be cross-linked (15%). This tendency toward intellectual isolation may be impeding efforts to achieve more powerful generalizations in ecology by reducing the number of potentially productive exchanges among researchers. In this paper, we illustrate this problem using the example of several speciality areas that study vegetation change. We argue that, rather than characterizing studies of vegetation change on the basis of what distinguishes them from one another, plant ecologists would benefit from concentrating on what such studies have in common. As an example, we propose that several speciality areas of plant ecology could be reunified under the term ecology of vegetation change. Individual researchers, journals, and ecological societies all can take specific steps to increase the useful exchange of ideas and information among research areas. Promoting rapid and more effective communication among diverse researchers may reduce the proliferation of narrow theories, concepts, and terminologies associated with particular research areas. In this way, we can expedite our understanding of the ecological mechanisms and consequences associated with plant communities. (c) 2004 Elsevier GmbH. All rights reserved.

The Carpathian mountain region is one of the most significant natural refuges on the European continent. It is home to Europe’s most extensive tracts of montane forest, the largest remaining virgin forest and natural mountain beech-fir forest ecosystems. Adding to the biodiversity are semi-natural habitats such as hay meadows, which are the result of centuries of traditional land management. Like other mountain regions areas, the Carpathian mountain region provides important ecosystem goods and services such as water provision, food products, forest products and tourism. But these ecosystem services are feared to be under threat from climate change.This chapter reports on climate trends, impacts and adaptation options. Analysis of climate trends show an increase in annual mean temperature of 1.1–2.0 °C over the last 50 years (1961–2010), further increasing by 3.5–4.0 °C towards the end of the century. Precipitation changes are dispersed with an increase of 300–400 mm in the north and decrease of 100–150 mm in the south regions. Summer precipitation is projected to reduce by 20 %, whereas winter precipitation is projected to increase in most areas by 5–20 % by the year 2100. Both future scenarios and observations show high spatial variability and uncertainty. The same holds for the impacts on the investigated sectors water resources, forests, wetlands, grasslands, agriculture and tourism.The review of climate trends and adaptation options, inspired a strategic agenda on adaptation to be implemented under the regional Carpathian Convention. Planning for climate change adaptation benefits from transnational cooperation because many impacts relate to seasonal and geographical shifts across borders. This is true for the natural system (e.g. shifts in species distribution and snow cover) as well as for socio-economic activities like agriculture, forestry and tourism (e.g. shifting opportunities for growing crops and changes in the tourist season). Examples of adaptation exist, yet need to be communicated for wider adoption. Essential components of adaptation will be capacity building and information sharing, climate-proofing of infrastructure and investments, promotion of eco-system based adaptation measures and making biodiversity management more dynamic.