Delimiting soil chemistry thresholds for nickel hyperaccumulator plants in Sabah (Malaysia)

Nickel hyperaccumulator plants have been the focus of considerable research because of their unique ecophysiological characteristics that can be exploited in phytomining technology. Comparatively little research has focussed on the soil chemistry of tropical nickel hyperaccumulator plants to date. This study aimed to elucidate whether the soil chemistry associated with nickel hyperaccumulator plants has distinctive characteristics that could be indicative of specific edaphic requirements. The soil chemistry associated with 18 different nickel hyperaccumulator plant species occurring in Sabah (Malaysia) was compared with local ultramafic soils where nickel hyperaccumulator plants were absent. The results showed that nickel hyperaccumulators in the study area were restricted to circum-neutral soils with relatively high phytoavailable calcium, magnesium and nickel concentrations. There appeared to be a ‘threshold response’ for the presence of nickel hyperaccumulator plants at >20 μg g^?1 carboxylic-extractable nickel or >630 μg g^?1 total nickel, and >pH 6.3 thereby delimiting their edaphic range. Two (not mutually exclusive) hypotheses were proposed to explain nickel hyperaccumulation on these soils: (1) hyperaccumulators excrete large amounts of root exudates thereby increasing nickel phytoavailability through intense rhizosphere mineral weathering; and (2) hyperaccumulators have extremely high nickel uptake efficiency thereby severely depleting nickel and stimulating re-supply of Ni from diffusion from labile Ni pools. It was concluded that since there was an association with soils with highly labile nickel pools, the available evidence primarily supports hypothesis (2).     

Pedogenesis and nickel biogeochemistry in a typical Albanian ultramafic toposequence

This study aimed at relating the variability of Ni biogeochemistry along the ultramafic toposequence to pedogenesis and soil mineralogy. Hypereutric Cambisols dominate upslope; Cambic Vertisols and Fluvic Cambisols occur downslope. The soil mineralogy showed abundance of primary serpentine all over the sequence. It is predominant upslope but secondary smectites dominate in the Vertisols. Free Fe-oxides are abundant in all soils but slightly more abundant in the upslope soils. Whereas serpentines hold Ni in a similar and restricted range in every soil (approx. 0.3 %), Ni contents in smectites may vary a lot and Mg-rich and Al-poor smectites in the Vertisol could hold up to 4.9 % Ni. Ni was probably adsorbed onto amorphous Fe-oxides and was also exchangeable in secondary smectites. High availability of Ni in soils was confirmed by DTPA extractions. However, it varied significantly along the toposequence, being higher in upslope soils, where Ni-bearing amorphous Fe-oxides were abundant and total organic carbon higher and sensibly lower downslope on the Vertisols: Ni_DTPA varied from 285 mg kg^?1 in the surface of soil I (upslope) to 95.9 mg kg^?1 in the surface of Fluvic Cambisols. Concentration of Ni in Alyssum murale shoots varied from 0.7 % (Hypereutric Cambisols) to 1.4 % (Hypereutric Vertisol). Amazingly, Ni uptake by A. murale was not correlated to Ni_DTPA, suggesting the existence of specific edaphic conditions that affect the ecophysiology of A. murale upslope.     

Bringing the outside in: Can “external” workers experience insider status?

The current study examines the possibility that agency workers can experience perceived insider status despite their assumed “outsider” category. One hundred ninety‐one agency workers from Canadian financial firms completed surveys assessing agency worker perceptions regarding the level of support from both their supervisors and the client firms' permanent workers, as well as the agency workers' level of perceived insider status and affective commitment toward the client firm. Agency worker supervisors (within the client firm) assessed the agency workers' level of interpersonal facilitation. Results indicate that: (1) Agency workers can experience perceived insider status, regardless of their objective classification as outsiders; (2) perceived support from supervisors and the client firms' permanent workers contribute to agency worker perceptions of insider status; and (3) perceptions of insider status are associated with higher levels of both affective commitment and interpersonal facilitation, even in workers that are considered marginally tied to the organization. Copyright © 2009 John Wiley & Sons, Ltd.     

GIS and local knowledge in disaster management: a case study of flood risk mapping in Viet Nam

Linking community knowledge with modern techniques to record and analyse risk related data is one way of engaging and mobilising community capacity. This paper discusses the use of the Geographic Information System (GIS) at the local level and the need for integrating modern technology and indigenous knowledge into disaster management. It suggests a way to mobilise available human and technical resources in order to strengthen a good partnership between local communities and local and national institutions. The paper also analyses the current vulnerability of two communes by correlating hazard risk and loss/damage caused by disasters and the contribution that domestic risk maps in the community can make to reduce this risk. The disadvantages, advantages and lessons learned from the GIS flood risk mapping project are presented through the case study of the Quang Tho Commune in Thua Thien Hue province, central Viet Nam.     

Characterisation and seasonal variations of particles in the atmosphere of rural, urban and industrial areas: Organic compounds

Atmospheric aerosol samples(PM_(2.5–0.3), i.e., atmospheric particles ranging from 0.3 to2.5 μm) were collected during two periods: spring–summer 2008 and autumn–winter 2008–2009, using high volume samplers equipped with cascade impactors. Two sites located in the Northern France were compared in this study: a highly industrialised city(Dunkirk) and a rural site(Rubrouck). Physicochemical analysis of particulate matter(PM) was undertaken to propose parameters that could be used to distinguish the various sources and to exhibit seasonal variations but also to provide knowledge of chemical element composition for the interpretation of future toxicological studies. The study showed that PM2.5–0.3concentration in the atmosphere of the rural area remains stable along the year and was significantly lower than in the urban or industrial ones, for which concentrations increase during winter.High concentrations of polycyclic aromatic hydrocarbons(PAHs), dioxins, furans and dioxin like polychlorinated biphenyls(DL-PCBs), generated by industrial activities, traffic and municipal wastes incineration were detected in the samples. Specific criteria like Carbon Preference Index(CPI) and Combustion PAHs/Total PAHs ratio(CPAHs/TPAHs) were used to identify the possible sources of atmospheric pollution. They revealed that paraffins are mainly emitted by biogenic sources in spring–summer whereas as in the case of PAHs, they have numerous anthropogenic emission sources in autumn-winter(mainly from traffic and domestic heating).     

Twin climate cities—an exploratory study of their potential use for awareness-raising and urban adaptation

Twin climate cities are pairs of cities for which it is appropriate to assume that the future climate of a city “A” will be significantly similar to the current climate of another city “B”. In this paper, we explore the potential use of the climate twins approach for the development of adaptation strategies to climate change in urban areas. We propose an innovative and robust climate-matching method that is suitable to link cities’ current and future climates. Of the 100 cities investigated, 70 have at least one twin climate region, and 39 have a twin climate city. The case-study revealed a highly significant similarity for temperature variables and heat-related indices, but a less significant similarity for precipitation variables. The Climate Twins approach appears to be a potentially effective mechanism for raising awareness about the pace of climate change and for easily identifying (1) future impacts and vulnerabilities associated with climate change as well as (2) policies, infrastructure, and best practices that should be implemented in a city in order to cope efficiently with future extreme temperature events.     

New insights on the systematics,palaeoecology and palaeobiology of a plesiosaurian with soft tissue preservation from the Toarcian of Holzmaden,Germany

The Posidonienschiefer Formation (Toarcian) of Holzmaden, Baden-Württemberg in southwestern Germany has yielded several excellently preserved plesiosaurian specimens and received considerable research attention. The plesiosaurians found within these deposits are always significantly outnumbered by ichthyosaurs, and close examination of these rare specimens is crucial to a better understanding of the diversity and palaeoecology of Plesiosauria in this very peculiar ecosystem. The plesiosaurian specimen SMNS 51945 found in this area is a juvenile individual consisting of a partial, crushed skull and an exquisitely preserved post-cranial skeleton. Its anatomical characters seem to differ from the long-necked plesiosauroids Microcleidus brachypterygius and Seeleyosaurus guilelmiimperatoris that are the most abundant taxa within the plesiosaurian assemblage. The post-cranial skeleton preserves very likely soft tissues composed of buff-coloured and dark-coloured structures around the vertebral column and hindlimb of the animal. A network of buff-coloured fibres located posterior to the hindlimb most likely represents phosphatised collagen fibres as already found in some ichthyosaur specimens, confirming that wing area in plesiosaurians was much larger than that suggested by skeletal remains alone. The specimen also contains gastroliths (sand-sized grains mainly composed of quartz) in the stomach cavity suggesting the animal spent at least some of its time in shallow coastal waters, tens or hundreds of kilometres from the final place of burial.     

Forest productivity decline caused by successional paludification of boreal soils.

Long-term forest productivity decline in boreal forests has been extensively studied in the last decades, yet its causes are still unclear. Soil conditions associated with soil organic matter accumulation are thought to be responsible for site productivity decline. The objectives of this study were to determine if paludification of boreal soils resulted in reduced forest productivity, and to identify changes in the physical and chemical properties of soils associated with reduction in productivity. We used a chronosequence of 23 black spruce stands ranging in postfire age from 50 to 2350 years and calculated three different stand productivity indices, including site index. We assessed changes in forest productivity with time using two complementary approaches: (1) by comparing productivity among the chronosequence stands and (2) by comparing the productivity of successive cohorts of trees within the same stands to determine the influence of time independently of other site factors. Charcoal stratigraphy indicates that the forest stands differ in their fire history and originated either from high- or low-severity soil burns. Both chronosequence and cohort approaches demonstrate declines in black spruce productivity of 50-80% with increased paludification, particularly during the first centuries after fire. Paludification alters bryophyte abundance and succession, increases soil moisture, reduces soil temperature and nutrient availability, and alters the vertical distribution of roots. Low-severity soil burns significantly accelerate rates of paludification and productivity decline compared with high-severity fires and ultimately reduce nutrient content in black spruce needles. The two combined approaches indicate that paludification can be driven by forest succession only, independently of site factors such as position on slope. This successional paludification contrasts with edaphic paludification, where topography and drainage primarily control the extent and rate of paludification. At the landscape scale, the fire regime (frequency and severity) controls paludification and forest productivity through its effect on soil organic layers. Implications for global carbon budgets and sustainable forestry are discussed.     

Effects of petroleum hydrocarbons on the cytochrome P450 content of the mollusc bivalveMytilus galloprovincialis

The cytochrome P₄₅₀, identified by the characteristic 450 nm spectral peak of its carbon monoxide complex, was detected in the hepatopancreatic microsomes ofMytilus galloprovincialis, collected from Ponteau (Bay of Fos, France) in 1982 and 1983. When mussels were exposed to a variety of petroleum hydrocarbons, the cytochrome P₄₅₀ content increased. It is shown that aromatic hydrocarbons are more effective than alkanes in inducing a high level of cytochrome P₄₅₀. The possible use of this haemoprotein in hydrocarbon pollutant detection is discussed.