Investigation of source apportioning for alpha-HCH using enantioselective analysis.

Enantiomeric analysis can be used as a complementary tool for source apportionment of chiral compounds, particularly for alpha-HCH. In this study we used archived samples from studies related to the distribution of POPs in air-water and air-soil-grass systems. Such approach is based on the behaviour of chiral compounds released into the atmosphere from a primary source, when they are expected to show racemic or close to racemic composition.

Jacob Christian Schäffer FRS, a versatile eighteenth-century naturalist, and his remarkable pioneering researches on microscopic crustaceans.

Jacob Christian Schäffer was the first to appreciate the morphological complexity of the microscopic crustacean Daphnia. His investigations, published in 1755, provide an excellent example of the difficulties facing those who, for the first time, attempted to elucidate the structure of extremely complicated animals of small size, of which there were no familiar counterparts. Nevertheless he not only revealed many hitherto unsuspected anatomical features but attempted, with some success, to explain their function.

Plant functional traits and soil carbon sequestration in contrasting biomes.

Plant functional traits control a variety of terrestrial ecosystem processes, including soil carbon storage which is a key component of the global carbon cycle. Plant traits regulate net soil carbon storage by controlling carbon assimilation, its transfer and storage in belowground biomass, and its release from soil through respiration, fire and leaching. However, our mechanistic understanding of these processes is incomplete.

Decabromodiphenyl ether (deca-BDE) commercial mixture components, and other PBDEs, in airborne particles at a UK site.

The occurrence of the major components of the decabromodiphenyl ether (deca-BDE) flame retardant and other PBDEs was investigated in daily air particulate samples from 17th April to 20th May 2004 at a semi-rural site in north-west England. BDE-209 was found at between <0.49 and 100 pg m(-3) (median 13 pg m(-3)), and other higher-brominated PBDE congeners were also found, particularly the nona-BDEs (e.

Heterotrophic microbial communities use ancient carbon following glacial retreat.

When glaciers retreat they expose barren substrates that become colonized by organisms, beginning the process of primary succession. Recent studies reveal that heterotrophic microbial communities occur in newly exposed glacial substrates before autotrophic succession begins. This raises questions about how heterotrophic microbial communities function in the absence of carbon inputs from autotrophs.

Preferences for different nitrogen forms by coexisting plant species and soil microbes.

The growing awareness that plants might use a variety of nitrogen (N) forms, both organic and inorganic, has raised questions about the role of resource partitioning in plant communities. It has been proposed that coexisting plant species might be able to partition a limited N pool, thereby avoiding competition for resources, through the uptake of different chemical forms of N. In this study, we used in situ stable isotope labeling techniques to assess whether coexisting plant species of a temperate grassland (England, UK) display preferences for different chemical forms of N, including inorganic N and a range of amino acids of varying complexity.

A temporal approach to linking aboveground and belowground ecology.

Ecologists are becoming increasingly aware of the role of aboveground-belowground relationships in controlling ecosystem processes and properties. Here, we review recent studies that show that relationships between aboveground and belowground communities operate over a hierarchy of temporal scales, ranging from days to seasons, to millennia, with differing consequences for ecosystem structure and function. We propose that a temporal framework is crucial to our understanding of the nature and ecological significance of relationships between aboveground and belowground communities.

Continental scale passive air sampling of persistent organic pollutants using rapidly equilibrating thin films (POGs).

A novel design of rapidly equilibrating passive air sampler was deployed at 38 sites across 19 European countries to investigate short-term spatial variability of persistent organic pollutants (POPs). Devices were sealed in airtight containers to eliminate the possibility of contamination during transit and couriered to recipients with deployment instructions. Exposure times of 7days permitted the use of back trajectory analysis to further understand the factors responsible for influencing the large-scale spatial distribution of PCBs, PBDEs, PCNs, PAHs, lindane and HCB.

Influence of the extraction methodology on the analysis of polycyclic aromatic hydrocarbons in pasture vegetation.

Pasture vegetation plays an important role in the air-surface exchange and food chain transfer of polycyclic aromatic hydrocarbons (PAHs). Therefore, considerable research has been focused towards measuring PAHs in vegetation using different analytical methods. However, in most cases information on the efficiencies of the different extraction methods employed is missing.

The action of RFamide neuropeptides on molluscs, with special reference to the gastropods Buccinum undatum and Busycon canaliculatum.

The ever-growing RFamide neuropeptide superfamily has members in all animal phyla. Their effects in molluscs, on both smooth and cardiac muscle as well as on neurons, has been studied in detail. These neuropeptides exert a variety of functions: excitatory, inhibitory or even biphasic.

Reductions and changing patterns of ambient PCDD/Fs in the UK: evidence and implications.

Archived herbage samples taken between the mid-1800s and the present day from the Park Grass permanent grassland experiment in the UK were analysed for PCDD/Fs. The concentrations of SigmaP((4-8))CDD/Fs ranged between 15 (in 2003-2004) and 320 pg/g (in 1963) and the SigmaTEQ ranged between 0.11 (2003-2004) and 2.

Parasitic plants indirectly regulate below-ground properties in grassland ecosystems.

Parasitic plants are one of the most ubiquitous groups of generalist parasites in both natural and managed ecosystems, with over 3,000 known species worldwide. Although much is known about how parasitic plants influence host performance, their role as drivers of community- and ecosystem-level properties remains largely unexplored. Parasitic plants have the potential to influence directly the productivity and structure of plant communities because they cause harm to particular host plants, indirectly increasing the competitive status of non-host species.

Causes and consequences of biological diversity in soil.

There is a vast diversity of organisms that live in the soil, and the activities of the total soil biota, together with the diverse forms and functions of plant roots, have critical roles in soil functioning. In this paper I discuss the likely determinants of soil diversity and also comment on recent studies that have explored whether or not there is a relationship between soil organism diversity and ecosystem function. There is little evidence to suggest that soil diversity is regulated in a predicable fashion by competition or disturbance; rather it is attributed to the nature of the soil environment, in that soil offers an extremely heterogeneous habitat, both spatially and temporally, proving unrivalled potential for niche partitioning, or resource or habitat specialisation, thereby enabling co-existence of species.

RFamide neuropeptide actions on the molluscan ventricle: Interactions with primary neurotransmitters.

Different RFamide neuropeptides, some of non-molluscan origin, were examined for their effect on the ventricles of Buccinum undatum and Busycon canaliculatum. None of the peptides tested were inhibitory on these ventricles. All the peptides were extremely active, causing excitation of the preparations at low concentrations.

Linking catabolism to cyclodextrin extractability: determination of the microbial availability of PAHs in soil.

When assessing the potential of a contaminated site for bioremediation, it is desirable to know how much of the contaminant(s) is available for microbial degradation, thus allowing the likelihood of successful bioremediation to be predicted. The aims of this study were to investigate the degradation of PAHs in two soils by a catabolic inoculum and indigenous soil microflora and link this to the cyclodextrin extractable fraction in the presence of transformer oil (0.05, 0.

Passive air sampling of polychlorinated biphenyls, organochlorine compounds, and polybrominated diphenyl ethers across Asia.

Asia is of global importance economically, yet data on ambient persistent organic pollutant levels are still sparse for the region, despite international efforts under the Stockholm Convention to identify and reduce emissions. A large-scale passive air sampling survey was therefore conducted in Asia, specifically in China, Japan, South Korea, and Singapore. Polyurethane foam disks were deployed simultaneously at 77 sites, between Sept 21 and Nov 16, 2004, and analyzed for polychlorinated biphenyls (PCBs), organochlorine compounds (hexachlorobenzene (HCB), dichlorodiphenyltrichloroethanes (DDTs), chlordane), and polybrominated diphenyl ethers (PBDEs).

Effect of cyclodextrin and transformer oil amendments on the chemical extractability of aged [14C]polychlorinated biphenyl and [14C]polycyclic aromatic hydrocarbon residues in soil.

Sequestration of hydrophobic organic contaminants (HOCs) in soils limits chemical and biological availability. Concerns exist regarding the long-term stability of sequestered contaminants in the environment, and stability needs to be demonstrated if bioavailability considerations are to be adopted into the risk assessment and remediation of contaminated land. The aim of the present study was to test the short-term influence of two organic amendments on the chemical extractability of HOC residues that had been present in soils for more than 12 years.

Distribution of aged 14C-PCB and 14C-PAH residues in particle-size and humic fractions of an agricultural soil.

Organic matter is considered to be the single most importantfactor limiting availability and mobility of persistent organic pollutants (POPs) in soil. This study aimed to characterize the distribution of 14C-PCB (congeners 28 and 52) and 14C-PAH (fluoranthene and benzo[a]pyrene) residues in an Orthic Luvisol soil obtained from two lysimeter studies initiated in 1990 at the Agrosphere Institute (Forschungszentrum Jülich GmbH, Germany). The lysimeter soils contained a low-density OM fraction, isolated during soil washing, which contained a significant fraction (3-12%) of the total 14C-activity.

Rising atmospheric CO2 reduces sequestration of root-derived soil carbon.

Forests have a key role as carbon sinks, which could potentially mitigate the continuing increase in atmospheric carbon dioxide concentration and associated climate change. We show that carbon dioxide enrichment, although causing short-term growth stimulation in a range of European tree species, also leads to an increase in soil microbial respiration and a marked decline in sequestration of root-derived carbon in the soil. These findings indicate that, should similar processes operate in forest ecosystems, the size of the annual terrestrial carbon sink may be substantially reduced, resulting in a positive feedback on the rate of increase in atmospheric carbon dioxide concentration.

Prediction of polycyclic aromatic hydrocarbon biodegradation in contaminated soils using an aqueous hydroxypropyl-beta-cyclodextrin extraction technique.

This study investigated the use of an aqueous hydroxypropyl-beta-cyclodextrin (HPCD) shake extraction to predict the degree of microbial degradation of polycyclic aromatic hydrocarbons (PAHs) in soils. Three different aged PAH-contaminated soils were studied: A soil from a former coke works (CW) and two artificially contaminated soils (AC1 and AC2). First, the catabolic activity of the indigenous soil microflora was assessed with 14C-respirometry, using a range of 14C-labeled aromatic compounds.

The influence of single and multiple applications of pyrene on the evolution of pyrene catabolism in soil.

The influence of pyrene added in a single application (0, 50, 100 and 200 mg kg(-1)) was investigated in multiple applications (1 x 50, 2 x 50 and 4 x 50 mg kg(-1)) on the evolution of catabolic activity in a pristine pasture soil. The microbial community's ability to degrade pyrene was assessed at 0, 4, 8 and 12 weeks by the mineralization of added 14C-pyrene. Significant mineralization (>5%) of added 14C-pyrene only occurred after 4 weeks soil-pyrene contact time in most of the pyrene-amended soils.

Temporal trends in the sources of PCDD/Fs to and around the Venice Lagoon.

Two salt marsh cores were collected from the Venice Lagoon, Italy, and analysed for PCDD/Fs. The samples were undisturbed and had an approximately constant accumulation rate. Radiochemical chronologies were established for the different core sections.

Reconstruction of historical trends of PCDD/Fs and PCBs in the Venice Lagoon, Italy.

Historical trends of PCDD/Fs and PCBs from the year 1900 have been reconstructed for the Venice Lagoon area by using a fugacity-based dynamic multimedia model. A novel approach to estimate the inputs to the system was applied. Emissions to the lagoon were estimated by studying dated sediment cores taken from salt marshes located in the lagoon area.