Thermogenic hydrocarbons in seawater of the Gippsland Shelf,southeast Australia

An offshore survey measured the concentration of thermogenic hydrocarbons (THCs) in samples extracted from seawater at 718 locations along 22 traverse lines across the Gippsland Shelf, southeast Australia, and recorded compounds typical of subsurface crude oil and natural gas (petroleum) accumulations. Background concentrations of 8 ppm, with isolated peak levels of 20 to 52 ppm, were detected in samples extracted from seawater at depths of 30 to 50 m over distances of 10 km. Two sources have been suggested — seepage of THCs from subsurface accumulations of petroleum, or THCs in waste-water discharged by several offshore petroleum production facilities which are present on the shelf. A waste-water source is favoured because of the transitory nature of the concentrations, and changes in composition consistent with plume drift away from the point(s) of discharge. Overall, however, the concentration of THCs in waters of the Gippsland Shelf compare favourably with levels in waters affected by urban runoff. The concentration of THCs in other coastal waters from urban and onshore sources is low, equivalent to the background concentration in the major oceans of the world.     

Studies on plant-mediated fate of the explosives RDX and HMX

The fate of the explosives RDX and HMX on exposure to plants was investigated in 'natural' aquatic systems of Myriophyllum aquaticum for 16 days, and in axenic hairy root cultures of Catharanthus roseus for > or = 9 weeks. Exposure levels were: HMX, 5 mg/l; and RDX, approximately 8 mg/l. Exposure outcomes observed include: HMX, no transformation by aquatic plants, and minimal biological activity by axenic roots; and RDX, removal by both plant systems. In the case of RDX exposure to axenic roots, since 14C-RDX was included, removal was confirmed by the accumulation of 14C-label in the biomass. The intracellular 14C-label in these RDX studies was detected in two forms: intact RDX and bound unknown(s).     

Klima?nderung — Was hei?t das?

Ohne Zusammenfassung     

Comparison of solubility databases used for HLW performance assessment

Elemental solubility limits are employed in many performance assessment studies of the disposal of high-level radioactive waste. A comparison of solubility databases used in a number of recent assessments from Canada, Finland, Japan, Sweden, Switzerland and the U.S.A. is presented. Despite similarities in the chemical conditions under which such solubilities are defined, there are very large ranges in the values selected for most elements (several orders of magnitude). In some cases, differences in solubilities can be attributed to differences in the thermodynamic databases used but, due to generally incomplete documentation, both of such databases and the criteria for data selection, detailed analysis of the reason for such discrepancies is precluded. A key factor, however, is the fairly subjective choice of the solid phase considered to be “solubility-limiting”. Procedures are recommended which would increase the transparency of solubility database compilation in future analyses.     

Effects of temperature on mineralisation of petroleum in contaminated Antarctic terrestrial sediments

Although petroleum contamination has been identified at many Antarctic research stations, and is recognized as posing a significant threat to the Antarctic environment, full-scale in situ remediation has not yet been used in Antarctica. This is partly because it has been assumed that temperatures are too low for effective biodegradation. To test this, the effects of temperature on the hydrocarbon mineralisation rate in Antarctic terrestrial sediments were quantified. 14C-labelled octadecane was added to nutrient amended microcosms that were incubated over a range of temperatures between -2 and 42 degrees C. We found a positive correlation between temperature and mineralisation rate, with the fastest rates occurring in samples incubated at the highest temperatures. At temperatures below or near the freezing point of water there was a virtual absence of mineralisation. High temperatures (37 and 42 degrees C) and the temperatures just above the freezing point of water (4 degrees C) showed an initial mineralisation lag period, then a sharp increase in the mineralisation rate before a protracted plateau phase. Mineralisation at temperatures between 10 and 28 degrees C had no initial lag phase. The high rate of mineralisation at 37 and 42 degrees C was surprising, as most continental Antarctic microorganisms described thus far have an optimal temperature for growth of between 20 and 30 degrees C and a maximal growth temperature <37 degrees C. The main implications for bioremediation in Antarctica from this study are that a high-temperature treatment would yield the most rapid biodegradation of the contaminant. However, in situ biodegradation using nutrients and other amendments is still possible at soil temperatures that occur naturally in summer at the Antarctic site we studies (Casey Station 66 degrees 17(') S, 110 degrees 32(') E), although treatment times could be excessively long.     

Global Supply of Biomass for Energy and Carbon Sequestration from Afforestation/Reforestation Activities

In this paper we provide an analytical framework to estimate the joint production of biomass and carbon sequestration from afforestation and reforestation activities. The analysis is based on geographical explicit information on a half-degree resolution. For each grid-cell the model estimates forest growth using a global vegetation model and chooses forest management rules. Land prices, cost of forest production and harvesting are determined as a function of grid specific site productivity, population density and estimates of economic wealth. The sensitivity of the results due to scenario storylines is assessed using different population and economic growth assumptions, which are consistent with B1 and A2 of the Intergovernmental Panel on Climate Change Special Report on Emission Scenarios (IPCC-SRES) marker scenarios. Considerable differences in the economic supply schedules are found. However, technical potentials seem to converge given constancy in other underlying assumptions of the model.     

Window-of-Opportunity for In Situ Burning

This paper is a summary of the fundamentals that influence the window-of-opportunity for in situ burning of oil at sea. It is a discussion of the variables and factors that influence the capabilities and limitations of in situ burning of oil. This includes the requirements for ignition and sustained burning and the factors that influence the quantity of residue and burn efficiency and the use of emulsion breakers.     

High-temperature tolerance of photosynthesis in the red alga Chondrus crispus

Chondrus crispus (Stackhouse) is a perennial red seaweed, common in intertidal and shallow sublittoral communities throughout the North Atlantic Ocean. In the intertidal zone, C. crispus may experience rapid temperature changes of 10 to 20C° during a single immerison-emerision cycle, and may be exposed to temperatures that exceed the thermal limits for long-term survival. C. crispus collected year-round at Long Cove Point, Chamberlain, Maine, USA, during 1989 and 1990, underwent phenotypic acclimation to growth temperature in the laboratory. This phenotypic acclimation enhanced its ability to withstand brief exposure to extreme temperature. Plants grown at summer seawater temperature (20°C) were able to maintain constant rates of lightsaturated photosynthesis at 30°C for 9 h. In contrast, light-saturated photosynthetic rates of plants grown at winter seawater temperature (5°C) declined rapidly following exposure to 30°C, reached 20 to 25% of initial values within 10 min, and then remained constant at this level for 9 h. The degree of inhibition of photosynthesis at 30°C was also dependent upon light intensity. Inhibition was greatest in plants exposed to 30°C in darkness or high light (600 mol photons m^-2s^-1) than in plants maintained under moderate light levels (70 to 100 mol photons m^-2s^-1). Photosynthesis of 20°C-acclimated plants was inhibited by exposure to 30°C in darkness or high light, but the degree of inhibition was less than that exhibited by 5°C-grown plants. Not only was light-saturated photosynthesis of 20°C plants less severely inhibited by exposure to 30°C than that of 5°C plants, but the former also recovered faster when they were returned to growth conditions. The mechanistic basis of this acclimation to growth temperature is not clear. Our results indicate that there were no differences between 5 and 20°C-grown plants in the thermal stability of respiration, electron transport associated with Photosystems I or II, Rubisco or energy transfer between the phycobilisomes and Photosystem II. Overall, our results suggest that phenotypic acclimation to seawater temperature allows plants to tolerate higher temperatures, and may play an important role in the success of C. crispus in the intertidal environment.     

The interpretation of planning appeals

The extent to which aggrieved applicants appeal against planning refusals varies between types of development, between regions and over time. So, too, though in lesser degree, does the extent to which appeals are successful. The paper seeks to explain these variations. It does so by arguing that the appeal rate varies with the support that central government ministers and their inspectors (the Central Planning Authority, CPA) give to the local planning authorities (LPAs), with appeal costs and with applicant and LPA willingness to renegotiate over refused applications. The appeal success rate is seen to be largely independent of the appeal rate and varies with potential appellants’ awareness of CPA policy and with their rationality.

It is concluded that appeal rate differences are best explained in terms of the CPA's support for the LPAs whether consideration is given to applications submitted nationally for different development types, to applications submitted in the eight English regions or to applications submitted in England and Wales over the period since 1974. Thus, CPA support for the LPAs is high in relation to change of use and householder developments but low in relation to development of the other major type; the CPA is less supportive of LPA policy in Yorkshire and Humberside and in East Anglia than in the other English regions, at least in the mid 1980s; and the CPA markedly reduced its support for the LPAs in England and Wales in the early 1980s.

It is also concluded that the low appeal success rate for minor residential development is the result of low appellant rationality, potential appellants being particularly determined to press their proposals against the odds. Appellant awareness of CPA policy and rationality may be comparable for the remaining development types since the appeal success rate shows little variation. Similarly, appellant awareness and rationality may be comparable in the eight English regions. In contrast, the appeal success rate in England and Wales as a whole has increased since 1974 perhaps because potential appellants are now more aware of CPA policy.