Effects of land use on soil respiration: conversion of oak woodlands to vineyards

We examined constraints on soil CO2 respiration in natural oak woodlands, and adjacent vineyards that were converted approximately 30 yr ago from oak woodlands, in the Oakville Region of Napa Valley, California. All sites were located on the same soil type, a Bale (variant) gravelly loam (fine-loamy, mixed, superactive, thermic Cumulic Ultic Haploxeroll) and dominated by C3 vegetation. Seasonal soil CO2 efflux was greatest at the oak woodland sites, although during the summer drought the rates of soil CO2 efflux measured from oak sites were generally similar to those measured from the vineyards. Soil profile CO2 concentrations at the oak woodland sites were lower below 15 cm despite higher CO2 efflux rates. Soil gas diffusion coefficients for oak sites were larger than for vineyard sites, and this indicated that the apparent discrepancy in soil profile carbon dioxide concentration ([CO2]) may be caused by a diffusion limitation. Soil profile [CO2] and delta13C values showed substantial temporal changes over the course of a year. Vineyard soil CO2 was more depleted in 13CO2 below 25 cm in the soil profile during the active growing season as indicated by more negative delta13C ratios. This result indicated that different C sources were being oxidized in vineyard soils. Annual C losses were less from vineyard soils (7.02 +/- 0.58 Mg C ha(-1) yr(-1)) as compared to oak soils (15.67 +/- 1.44 Mg C ha(-1) yr(-1)), and both were comparable to losses reported in previous investigations.     

Spawning and development in <Emphasis Type="Italic">Osedax</Emphasis> boneworms (Siboglinidae,Annelida)

We report observations on spawning and early development in bone-eating worms of the genus Osedax. Individual females of Osedax rubiplumus were observed at 1820 m depth freely spawning hundreds of oocytes, and females of an undescribed species, Osedax “orange collar”, were observed spawning in laboratory aquaria. Cytological and molecular analysis of the spawned oocytes of two Osedax species revealed no evidence for the bacterial endosymbionts that the female worms require for their nutrition, suggesting that the bacteria must be acquired later from the environment, as they are in other siboglinids. Individual O. “orange collar” females released an average of 335 (±130) eggs per day, but the number of oocytes spawned per day varied greatly, suggesting that not all the females spawned daily. Fertilization rates of the spawned oocytes varied from 0 to 100%, though most females showed nearly 100% fertilization rates. Oocytes spawned in the laboratory at 4–6°C were negatively buoyant. If fertilized, these oocytes extruded polar bodies and then after at least four hours cleaved unequally. Subsequent cleavages occurred in a spiral pattern at roughly 2-h intervals, resulting in free-swimming trochophore larvae after 24 h. These lecithotrophic trochophores swam for 9–16 days before settling with several hooked chaetae, similar to those of dwarf Osedax males. The larval life span of the Osedax species studied in the laboratory appears to be shorter than in closely related Vestimentifera. Osedax rubiplumus, on the other hand, has much larger oocytes and so may have greater dispersal potential than these other Osedax species. The high fecundity and apparently continuous reproduction of Osedax boneworms permits the opportunistic exploitation of sunken vertebrate bones. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Beyond the Guidelines: Practical lessons for monitoring

A series of workshops have provided extensive feedback on a recently published manual, Monitoring Guidelines to Evaluate Effects of Forestry Activities on Streams in the Pacific Northwest and Alaska (Guidelines) (MacDonald et al., 1991). These workshops and other discussions have led to the identification of fourteen additional lessons for monitoring. These lessons are concepts which either were not incorporated into the Guidelines, were not sufficiently emphasized, or which are needed to put the Guidelines in context. The topics include: monitoring as a continuum; defining objectives and hypotheses; peer review; uncertainty and risk; upslope vs. instream monitoring; photo sequences; scale considerations; data storage, data interpretation, and data base management; activities monitoring; and personal commitment as a critical component in monitoring projects. Many of these lessons might appear self-evident, but our experience indicates that they are often ignored. Like the Guidelines, these lessons are widely applicable and should be explicitly recognized when formulating and conducting monitoring projects.     

Detecting the signal of atmospheric N deposition in recent national-scale vegetation change across Britain

Model estimates of NO_y and NH_x deposition across Britain for 1996 (5 km square resolution) were applied as explanatory variables to account for national-scale, fine-grained changes in plant species composition between 1990 and 1998. Plant species data were recorded from up to 27 fixed plots located within a stratified random sample of 596 1 km². The response variable was a cover-weighted Ellenberg fertility score for each plot. Analyses were carried out separately for woodlands, semi-natural grasslands and heaths/bogs. Most of the variation in the botanical response variable occurred between plots within squares and so could not be explained by the model deposition data. NH_x deposition estimates accounted for significant, but small components of between 1 km² variation in the change in Ellenberg score in grasslands (5.6%) and heath/bogs (9.8%) but not woodlands. NO_y deposition estimates were not significantly associated with vegetation change. Linear models provided the best fit and the slope of the relationship was lower for heath/bogs than grasslands. Further signal attribution at sub-kilometre square scales requires the development of fine-grained models of N deposition that can be generalised across regional sampling domains.     

Controls on leaching of N species in upland moorland catchments

Spatial and temporal changes in mobility of N species have been studied for three UK upland river networks, the Etherow in the South Pennines, the Nether Beck in the Lake District and the Dee in NE Scotland. The catchments are subject to N deposition at 35.1, 22.0 and 10.8–15.6 kg N ha^?1 yr^?1, respectively. The NH⁺ ₄ leaching appears to be predominantly regulated by flow path in more polluted upland catchments. It is greatest where water draining acidified peaty soils contributes more to total discharge. Soluble organic matter may provide the dominant counter anion. In the Etherow and Dee catchments, which are dominated by acid mineral and organic soils, at high discharge NO^? ₃ also appears to be associated with greater input of water from acidified soils. In contrast, for the Nether Beck, higher NO^? ₃ concentrations are associated with tributaries draining soils contributing water with higher alkalinity, suggesting nitrification is important. For the Etherow and Dee, dissolved organic N (DON) appears to originate predominantly from acidified, peaty soils. Spiking experiments with peat soil from the Etherow catchment confirmed the limited capacity of these soils to utilize inorganic N inputs, favouring equilibration with NH⁺ ₄ inputs and leaching losses of inorganic N throughout the year.     

Disaster studies inside out

Disaster studies is faced with a fascinating anomaly: frequently it claims to be critical and innovative, as suggested by the so‐called vulnerability paradigm that emerged more than 40 years ago, yet often it is perpetuating some of the core and problematic tenets of the hazard paradigm that we were asked to challenge initially. This paper interrogates why such an anomaly persists. In so doing, it employs Antonio Gramsci's concept of hegemony to unpack why disaster studies is still dominated by Western epistemologies and scholars that perpetuate an orientalist view of disasters. Ultimately, it suggests a research agenda for the 40 years to come, which builds on the importance of local researchers analysing local disasters using local epistemologies, especially in the non‐Western world. Such subaltern disaster studies are to be fuelled by increasing consciousness of the need to resist the hegemony of Western scholarship and to relocate disaster studies within the realm of its original political agenda.     

Road rage experience and behavior: vehicle, exposure, and driver factors

Road rage has generated increasing public concern. Research has shown that victimization and perpetration of road rage is more common among males and younger drivers. We aimed to extend the understanding of determinants of road rage to driving exposure and vehicle factors, based on a 20022003 population survey of 1,631 regular drivers in Ontario, Canada. Regression analyses revealed that number of times drivers reported experiencing road rage in the previous 12 months was significantly greater for males, younger respondents, and those residing in Toronto. Also, victimization was significantly greater for drivers who did all their driving on busy roads and increased with number of kilometers driven on a typical week; however, type of vehicle driven was not significant. Number of times road rage perpetration was reported in the past 12 months was significantly greater for males, younger respondents, and those residing in Toronto, and lower for those in the Eastern and Northern region. Road rage perpetration increased significantly with number of weekly kilometers driven and was significantly greater for drivers who are always on busy roads and lower for those who never drive on busy roads, and higher for high-performance vehicle drivers. Even after controlling for driving exposure, road rage victimization and perpetration were highest for drivers in Toronto, where the pace of life may be more demanding. As expected, high-performance vehicle drivers reported more road rage perpetration. These individuals may experience more frustration when they are prevented from using the full performance capacities of their vehicles by crowded urban roadways.     

Synthesis of chromium-containing pigments from chromium recovered from leather waste

Cobalt-chromite green and chrome-tin pink pigments have been prepared from chromium extracted from leather shavings produced as a waste product of the leather-tanning industry. The alkaline agent (NaOH, CaO, MgO, NH4OH) used in the extraction process influences the nature of the final product. The effect of the NH4OH:CaO ratio on the final product in the case of cobalt-chromite green was examined. The pigments obtained were characterized by FT-IR and X-ray diffraction (XRD). Colour measurements were compared with those recorded from materials prepared from pure Cr2O3. The leaching of Cr(VI) from the materials was examined by UV spectroscopy.