Die Bedeutung der Zeit

The consideration of time in environmental research allows new insights into the fundamentals of environmental research and new pathways for perceiving and answering questions which might arise in environmental research. In order to take this all into account, one must realize that ecological systems have a history and that both the spatial aspects and the chronological expansion of these systems must be taken into consideration. Considering temporalities, rhythms and time scales as well as their interdependencies in environmental research and environmental protection enables us to obtain a better understanding. The significance of relationships and functions in ecological systems can be perceived better as well. The impact of pollutants as well as the outcome of human actions in ecology, and in economics and politics, is consequently mandatory for not only a spatial, but also for the involved temporal scales.     

Homogeneity and stability study of the candidate reference material Adamussium colbecki for trace elements

The preparation of a new candidate certified reference material (CRM) for trace elements based on the antarctic bivalve Adamussium colbecki(IRMM 813) was carried out by the Istituto Superiore di Sanità(ISS, Rome, Italy) in cooperation with the Institute for Reference Materials and Measurements, Joint Research Centre of the European Commission (EC-JRC-IRMM), in the frame of the Italian National Programme of Research in Antarctica (Programma Nazionale di Ricerca in Antartide, PNRA). Samples were collected at Terra Nova Bay (Ross Sea) during the 2000-2001 expedition in Antarctica. The preparation of a material suitable for certification was performed by the EC-JRC-IRMM. Measurements for homogeneity and short-term stability tests were carried out by ISS. The elements selected for the certification project were As, Cd, Cu, Cr, Fe, Mn, Ni and Zn. For the above-mentioned tests, the determination of the elements of interest was performed on samples mineralised by microwave-assisted acid digestion. The analytical techniques employed to this end were inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma dynamic reaction cell quadrupole mass spectrometry (ICP-DRC-Q-MS). The candidate material was shown to be fit for purpose with regard to homogeneity and short-term stability, thus allowing the following phases of the certification project to be undertaken, in the first place the selection of expert laboratories for the accomplishment of the certification campaign.     

Atmospheric phase distribution of oxidized and reduced nitrogen at a forest ecosystem research site

Atmospheric concentrations of gaseous NH3 and HNO3 and of particulate NH4+ and NO3- were measured during various seasons at a forest ecosystem research site in the "Fichtelgebirge" mountains in Central Europe. Air masses arriving at this site were highly variable with respect to trace compound concentration levels and their concentration ratios. However, the distributions of NH4+ and NO3- within the aerosol particle size spectra exhibited some very consistent patterns, with the former dominating the fine particle concentrations, and the latter dominating the coarse particles range, respectively. Overall, the particulate phase (NH4+ + NO3-) dominated the atmospheric nitrogen budget (particulate and gas phase, NH4+ + NO3- + NH3 + HNO3) by more than 90% of the median total mixing ratio in winter, and by more than 60% in summer. The phase partitioning varied significantly between the winter and summer seasons, with higher relative importance of the gaseous species during summer, when air temperatures were higher and relative humidities lower as compared to the winter season. Reduced nitrogen dominated over oxidized nitrogen, indicating the prevailing influence of emissions from agricultural activity as compared to traffic emissions at this mountainous site. A model has been successfully applied in order to test the hypothesis of thermodynamic equilibrium between the particulate and gas phases.     

Long-distance island hopping without dispersal stages: transportation across major zoogeographic barriers in a Southern Ocean isopod

Species integrity is maintained only if recurrent allelic exchange between subpopulations occurs by means of migrating specimens. Predictions of this gene flow on the basis of observed or assumed mobility of marine species have proven to be error-prone. Using one mitochondrial gene and seven microsatellite markers, we studied the genetic structure and gene flow in Septemserolis septemcarinata, a strictly benthic species lacking pelagic larvae and the ability to swim. Suitable shallow-water habitats around three remote islands (South Georgia, Bouvet, and Marion Island) are geographically disjunct, isolated by more than 2,000 km of uninhabitable deep sea (east–west) and also separated by the Polar Front (north–south), which serves as a strong demarcation line in many marine taxa. Although we did find genetic differentiation among the three island populations, our results also revealed that a scenario with recent gene flow explains our data best. A model assuming no gene flow after initial colonization of the islands performs significantly worse. The tests also favor an asymmetric gene flow pattern (west to east ≫ east to west) thus mirroring the directionality of major oceanographic currents in the area. We conclude that rare long-distance dispersal rather than vicariance or human-mediated transport must be responsible for the observed patterns. As a mechanism, we propose passive rafting on floating substrata in the Antarctic Circumpolar Current. The results demonstrate that the effectiveness of a physical barrier is not solely a function of its physical parameters but strongly depends on how organisms interact with their environment.     

Biotransformation of phenolics with laccase containing bacterial spores

Treatment of effluents containing phenols such as textile dyes with fungal laccases is usually limited to the acid to neutral pH range and moderate temperatures. Here we demonstrate for the first time that spore-bound laccases which are stable at high temperatures and pH values can be used for phenolic dye decolorisation. Laccase containing spores from Bacillus SF were immobilized on alumina pellets. Both immobilized and free spores were able to completely decolorize the common textile dyes Mordant Black 9, Mordant Brown 96/Mordant Brown 15, and Acid Blue 74 within 90 min of incubation time and decolorized solutions were successfully used in re-dyeing.     

Spatial variation of volatile organic compounds in a "Hot Spot" for air pollution

The spatial variations of volatile organic compounds (VOCs) were characterized in the Village of Waterfront South neighborhood (WFS), a "hot spot" for air toxics in Camden, NJ. This was accomplished by conducting "spatial saturation sampling" for 11 VOCs using 3500 OVM passive samplers at 22 sites in WFS and 16 sites in Copewood/Davis Streets (CDS) neighborhood, an urban reference area located ～1000 m east of the WFS. Sampling durations were 24 and 48 h. For all 3 sampling campaigns (2 in summer and 1 in winter), the spatial variations and median concentrations of toluene, ethylbenzene, and xylenes (TEX) were found significantly higher (p < 0.05) in WFS than in CDS, where the spatial distributions of these compounds were relatively uniform. The highest concentrations of methyl tert-butyl ether (MTBE) (maximum of 159 μg m(-3)) were always found at one site close to a car scrapping facility in WFS during each sampling campaign. The spatial variation of benzene in WFS was found to be marginally higher (p = 0.057) than in CDS during one sampling campaign, but similar in the other two sampling periods. The results obtained from the analyses of correlation among all species and the proximity of sampling site to source indicated that local stationary sources in WFS have significant impact on MTBE and BTEX air pollution in WFS, and both mobile sources and some of the stationary sources in WFS contributed to the ambient levels of these species measured in CDS. The homogenous spatial distributions (%RSD < 24%) and low concentrations of chloroform (0.02-0.23 μg m(-3)) and carbon tetrachloride (0.45-0.51 μg m(-3)) indicated no significant local sources in the study areas. Further, results showed that the sampling at the fixed monitoring site may under- or over-estimate air pollutant levels in a "hot spot" area, suggesting that the "spatial saturation sampling" is necessary for conducting accurate assessment of air pollution and personal exposure in a community with a high density of sources.     

Observations and Model Simulations of Carbon Monoxide Emission Factors from a California Highway

ABSTRACT

A series of twelve intensively monitored 1-hr CO dispersion studies were conducted near Davis, CA, in winter 1996. The experimental equipment included twelve CO sampling ports at elevations up to 50 m, three sonic anemometers, a tethersonde station, aircraft measurements of wind and temperature profile aloft, and a variety of conventional meteorological equipment. The study was designed to explore the role of vehicular exhaust buoyancy during worst-case meteorological conditions, such as low winds oriented in near-parallel alignment with the road during a surface-based nocturnal inversion. From the study, field estimates of the CO emission factor (EF) from a California vehicle fleet were computed using two different methods. The analysis suggests that the CT-EMFAC/ EMFAC (EMission FACtor) models currently used to conduct federal conformity modeling significantly overpredict CO emissions for high-speed, free-flowing traffic on California highways.