Charakterisierung von Holzasche aus Biomassefernheizwerken

As a result of forcing the energy utilization from biomass, the amounts of combustion residues, especially woodash, are growing. For a sustainable and ecologically effective closed-cycle economy, the knowledge of the chemical composition of the ashes is necessary. The matrix wood ash is very complex, due to the great number of constituents in different concentrations. Therefore it is important to develop a combination of analytical methods for the complete detection of nutrients and heavy metals in wood ash. Ashes from different heating plants (wood chips-, bark-and sawdust combustion systems) were analysed with X-ray methods as well as with acid-digestion in combination with atomic spectrometry detection. The results were compared and checked for their plausibility by statistical methods and material balances for the inorganic elements from the biomass to the ash fractions. As a result of this evaluation astandard method is recommended for the analysis of wood ash. This method consists of a combination of dry (X-ray) analysis (for the elements Si, Ca, Mg, K, P, Al, Fe, Mn) and fluid analysis (for the detection of heavy metals).     

Neue horizonte für die chemie

The term ‘sustainable development’ is defined and discussed with regard to its significance and its application in the field of chemistry. This is presented using the synthetic organic chemistry as an example. A review of the history of chemistry indicates clearly the necessity for further developments in the course of concepts involving sustainability. Following the eras of bituminous coal tar and mineral oil in both of the two past centuries, a search for new raw materials and a reduction in the global ecotoxicological potential for danger is being strived for. Critical contemplations are mandatory in order to avoid making this term ‘persistence’ into a keyword. Consequently, one must take into consideration the field of research and development as well as reflecting about the classification of chemical and scientific research projects, and their political as well as social relationships. Aside from the new methods of synthesis, this will also require the formulation of other decision-relevant criteria.     

Production and Consumption of NO in Forest and Pasture Soils from the Amazon Basin

NO production and the rate constant of NO consumptionin soil samples from Amazonian forest and pasturesites were determined in the laboratory. The purposewas to study NO production and consumption in soilsfrom both types of land use as functions of soiltemperature and soil moisture. NO productionincreased exponentially with soil temperature. Thedegree of increase depended on soil moisture,indicating that the response of NO production to achange in soil temperature is most pronounced at acertain intermediate soil moisture. NO productionpeaked at a soil moisture of 0.10 g g^-1, correspondingto 0.27 and 0.38 water-filled pore space for forestand pasture soils, respectively. The optimum soilmoisture for which maximum NO release was observedwas independent of soil temperature. NO consumptionwas most efficient at high soil temperatures andunder dry soil conditions. NO release wasapproximately 10 times larger for forest than pasturesoil. The difference may be related to the higherNO₃ ^- content in forest soil.     

Trace Metal Studies on the Starfish Asterias rubens L. From the Western Baltic Sea

In 1984, 115 samples of the starfish Asterias rubens L. collected in the south-eastern part of Cadet Trench (Mecklenburg Bay/Western Baltic Sea) were analyzed for their contents of a few major (calcium, magnesium) and trace elements (cadmium, copper, iron, mercury, manganese, nickel, lead, selenium and zinc). Distinct differences were found between starfish from different stations, and these are attributed to the composition of the sediments acting as a substrate for their prey (mussels, snails). Except for cadmium, the concentrations of the elements studied all correlated negatively with the diameter and weight of the starfish.

Parallel analyses of starfish arms and the central discs of the same animals showed that iron, zinc, copper and mercury levels were 16 to 30% higher, and selenium, manganese, magnesium, calcium and lead were 4 to 9% higher in the arms. Cadmium concentrations were 20% higher in the central discs than in the arms.

Stock estimations (about 52,000 tons fresh weight) show that starfish play a significant role in the benthic ecosystem of the western Baltic Sea. They can consume up to 200,000 tons of mussels and clams (Mytilus edulis, Macoma baltica) a year and may therefore represent a notable factor in the trace metal balance of the region.     

Female great tits do not alter their yolk androgen deposition when infested with a low-transmittable ectoparasite

In birds as in many other taxa, parasites can have deleterious effects on offspring development. Therefore, avian mothers have evolved responses to counteract parasite virulence in offspring via transgenerational defense mechanisms that is the transfer of immune-enhancing substances such as antibodies to their eggs. Another maternal pathway is suggested by the finding that infested great tit mothers produced eggs with lower androgens, since these yolk androgens are immunosuppressive and potentially affect parasite susceptibility of the nestlings. However, whether this pathway is a specific adaptation to infestation with parasites that affect the offspring or an epiphenomenon of lower androgen production in the female due to the parasite effects on the mother itself is as yet unclear. In this study we infested female great tits (Parus major) with sheep ticks (Ixodes ricinus), which are nonnidicolous ectoparasites with low vertical transmission capability, and evaluated the effects on yolk androgen deposition. Tick-infested females did not significantly reduce their deposition of androgens (androstenedione (A₄) and testosterone) compared to tick-reduced females, which is in contrast to a previous study showing a lowered deposition of A₄ and testosterone when females were exposed to the nidicolous hen flea. Thus, females alter their hormone deposition, and thus likely offspring phenotype, when exposed to parasites that also form the parasitic environment of their offspring, but not when temporarily infested with the field-dwelling sheep ticks with low transmission capability. This suggests that selection favored the evolution of an adaptive transgenerational effect by acting mainly on the parasite-induced maternal effect.     

Tracking migration routes and the annual cycle of a trans-Sahara songbird migrant

Movement ecology studies have highlighted the importance of individual-based research. As tracking devices have not been applicable for identifying year-around movements of small birds until recently, migration routes of such species relied on visual observations and ring recoveries. Within the Palaearctic–African migration system, loop migration seems to be the overall migration pattern. The interindividual variations within species-specific migration routes are, however, unknown. Here, we track the individual migration routes and annual cycles of male Northern Wheatears Oenanthe oenanthe, a trans-Sahara songbird migrant from a German breeding population with light-level geolocators. Two migrated most likely via Spain towards western Africa but returned via Corsica/Sardinia, while two others seemed to migrate via Sardinia and Corsica in autumn and via Spain and France in spring (loop migration). The fifth took presumably the same route via France and the Balearics in both seasons. All birds wintered in the Sahel zone of western Africa. Overall migration distances for autumn and spring were similar (about 4,100?km), whereas the overall migratory speed was generally higher in spring (126?km?day^?1) than in autumn (88?km?day^?1). Birds spent about 130?days at the breeding area and 147?days at the wintering grounds.     

Windows of change: temporal scale of analysis is decisive to detect ecosystem responses to climate change

Long-term ecological research has become a cornerstone of the scientific endeavour to better understand ecosystem responses to environmental change. This paper provides a perspective on how such research could be advanced. It emphasizes that a profound understanding of the mechanisms underlying these responses requires that records of ecologic processes be not only sufficiently long, but also collected at an appropriate temporal resolution. We base our argument on an overview of studies of climate impacts in limnic and marine ecosystems, suggesting that lakes and oceans respond to (short-term) weather conditions during critical time windows in the year. The observed response patterns are often time-lagged or driven by the crossing of thresholds in weather-related variables (such as water temperature and thermal stratification intensity). It becomes clear from the previous studies that average annual, seasonal or monthly climate data often fall short of characterizing the thermal dynamics that most organisms respond to. To illustrate such literature-based evidence using a concrete example, we compare 2?years of water temperature data from Müggelsee (Berlin, Germany) at multiple temporal scales (from hours to years). This comparison underlines the pitfalls of analysing data at resolutions not high enough to detect critical differences in environmental forcing. Current science initiatives that aim at improving the temporal resolution of long-term observatory data in aquatic systems will help to identify adequate timescales of analysis necessary for the understanding of ecosystem responses to climate change.     

COLIWAVE a simulation model for survival of E. coli O157:H7 in dairy manure and manure-amended soil

A simulation model was developed to investigate the relative effects of temperature, oxygen concentration, substrate content and competition by autochthonous microbial community on the oscillatory behaviour and survival of Escherichia coli O157:H7 in manure and manure-amended soil. The overall decline in E. coli O157:H7 was primarily determined by competition with autochthonous copiotrophic bacteria simulated by an inter-specific competition term according to Lotka-Volterra. Oscillations of bacterial populations were attained by the relationships between relative growth and death rates with readily available substrate content. The model contains a logistic and exponential relation of relative growth and death rates, respectively, of E. coli O157:H7 and copiotrophic bacteria with temperature, resulting in optimum curves for net growth rates similar to the curves reported in the literature. The model has been both calibrated and validated on experimental data. The model was used to perform sensitivity analysis and to evaluate different manure and soil management scenarios in terms of survival of E. coli O157:H7. The relative effects of changes in temperature on simulated survival time of E. coli O157:H7 were more pronounced than changes in oxygen condition. Testing manure storage scenarios with realistic data revealed that manure stored in a heap that was turned every week resulted in almost 70% reduction of E. coli O157:H7 survival compared to unturned manure. At the surface of a heap with unturned manure, simulated survival time was the longest (2.4 times longer than inside the same heap). The simulation model provides a new approach to investigating dynamic changes of invasive microorganisms in natural substrates such as manure or manure-amended soil.     

Nonequilibrium coexistence in a competition model with nutrient storage

Resource competition theory predicts that, in equilibrium, the number of coexisting species cannot exceed the number of limiting resources. In some competition models, however, competitive interactions may result in nonequilibrium dynamics, allowing the coexistence of many species on few resources. The relevance of these findings is still unclear, since some assumptions of the underlying models are unrealistic. Most importantly, these models assume that individual growth directly reflects the availability of external resources, whereas real organisms can store resources, thereby decoupling their growth from external fluctuations. Here we study the effects of resource storage by extending the well-known Droop model to the context of multiple species and multiple resources. We demonstrate that the extended Droop model shows virtually the same complex dynamics as models without storage. Depending on the model parameters, one may obtain competitive exclusion, stable equilibrium coexistence, periodic and non-periodic oscillations, and chaos. Again, nonequilibrium dynamics allows for the coexistence of many species on few resources. We discuss our findings in the light of earlier work on resource competition, highlighting the role of luxury consumption, trade-offs in competitive abilities, and ecological stoichiometry.     

Obligatory barrier crossing and adaptive fuel management in migratory birds: the case of the Atlantic crossing in Northern Wheatears (<Emphasis Type="Italic">Oenanthe oenanthe</Emphasis>)

Behaviour on migration was often suggested to be selected for time-minimising strategies. Current optimality models predict that optimal fuel loads at departure from stopover sites should increase with increasing fuel deposition rates. We modified such models for the special case of the east Atlantic crossing of the Northern Wheatear (Oenanthe oenanthe). From optimality theory, we predict that optimal time-minimising behaviour in front of such a barrier should result in a positive correlation between fuel deposition rates and departure fuel loads only above a certain threshold, which is the minimum fuel load (f _min) required for the barrier crossing. Using a robust range equation, we calculated the minimum fuel loads for different barrier crossings and predict that time-minimising wheatears should deposit a minimum of 24% fuel in relation to lean body mass (m ₀ ) for the sea crossing between Iceland and Scotland. Fuel loads of departing birds in autumn in Iceland reached this value only marginally but showed positive correlation between fuel deposition rate (FDR) and departure fuel load (DFL). Birds at Fair Isle (Scotland) in spring, which were heading towards Iceland or Greenland, were significantly heavier and even showed signs of overloading with fuel loads up to 50% of lean body mass. Departure decisions of Icelandic birds correlated significantly with favourable wind situations when assuming a migration direction towards Spain; however, the low departure fuel loads contradict a direct non-stop flight.