Experimental ecology of the temperate scleractinian coral Astrangia danae I. Partition of respiration,photosynthesis and calcification between host and symbionts

Calcification, photosynthesis and respiration of the scleractinian coral Astrangia danae were calculated from the changes in total alkalinity, pH, calculated total CO₂, and oxygen concentration produced by colonies incubated in glass jars. A correction for changes in ammonia, nitrate and nitrite was taken into account and the method evaluated. The fluxes of oxygen and CO₂ were highly correlated (r=0.99). The statistical error of alkalinity determinations was less than 10% of the changes observed in the slowest calcifying samples. Metabolism of polyparium alone was estimated by difference after removal of tissue and reincubation of bare corallum. Zooxanthellae concentration in the polyps was obtained from cell counts made on homogenates of polyp tissue. The calculated photosynthetic rate of the zooxanthellae in vivo was 25 mol O₂ (10⁸ cell)^-1 h^-1 at a light intensity of 120 Ein m^-2 s^-1. In corals having 0.5x10⁹ zooxanthellae/dm² of colony area up to 8% of the total photosynthesis was attributed to the corallum microcosm. Polyp respiration, photosynthesis, and CaCO₃ uptake rates were all much higher than rates previously reported from A. danae, apparently because in these experiments the organisms were better fed. This increased photosynthesis in turn enhanced calcification still further. The symbiosis therefore appears to provide a growth advantage even to fed corals, under the conditions of these experiments.     

Choosing a sustainable demolition waste management strategy using multicriteria decision analysis

This paper presents an application of the ELECTRE III decision-aid method in the context of choosing a sustainable demolition waste management strategy for a case study in the city of Lyon, France. This choice of waste management strategy takes into consideration the sustainable development objectives, i.e. economic aspects, environmental consequences, and social issues. Nine alternatives for demolition waste management were compared with the aid of eight criteria, taking into account energy consumption, depletion of abiotic resources, global warming, dispersion of dangerous substances in the environment, economic activity, employment, and quality of life of the local population. The case study concerned the demolition of 25 buildings of an old military camp. Each alternative was illustrated with different waste treatments, such as material recovery, recycling, landfilling, and energy recovery. The recommended solution for sustainable demolition waste management for the case study is a selective deconstruction of each building with local material recovery in road engineering of inert wastes, local energy recovery of wood wastes, and specific treatments for hazardous wastes.     

Sequestration of plant pyrrolizidine alkaloids by chrysomelid beetles and selective transfer into the defensive secretions

Summary Oreina cacaliae andO. speciosissima (Coleoptera, Chrysomelidae) sequester in their elytral and pronotal defensive secretions pyrrolizidine alkaloids (PAs) as Noxides (PA N-oxides). The PA N-oxide patterns found in the beetles and their host plants were evaluated qualitatively and quantitatively by capillary gas chromatography/mass spectrometry (GC-MS). Of the three host plantsAdenostyles alliariae (Asteraceae) is the exclusive source for PA N-oxide sequestration in the defensive secretions of the beetles. With the exception of O-acetylseneciphylline the N-oxides of all PAs ofA. alliariae, i.e. senecionine, seneciphylline, spartioidine, integerrimine, platyphylline and neoplatyphylline were identified in the secretion. PA N-oxides typical ofSenecio fuchsii (Asteraceae) were detected in the bodies of the beetles but not in their secretion. No PAs were found in the leaves of the third host plant,Petasites paradoxus (Asteraceae). The results suggest the existence of two distinctive storage compartments for PA N-oxides in the beetle: (1) the defensive secretion, containing specifically PA N-oxides acquired fromA. alliariae; (2) the body of the beetle, sequestering additionally but less selectively PA N-oxides from other sources,e.g. S. fuchsii or monocrotaline N-oxide fed in the laboratory. The concentration of PA N-oxides in the defensive secretion is in the range of 0.1 to 0.3 mol/1, which is more than 2.5 orders of magnitude higher than that found in the body of the beetle. No significant differences exist in the ability of the two species of beetles to sequester PA N-oxides fromA. alliariae, althoughO. speciosissima, but notO. cacaliae, produces autogenous cardenolides. A negative correlation seems to exist between the concentrations of plant-derived PA N-oxides andde novo synthesized cardenolides in the defensive secretion ofO. speciosissima.     

Photochemistry and environment IV- Photochemical behaviour of monochlorophenols in dilute aqueous solution

The photochemical behaviour of chlorophenols is different to that of non-halogenated phenols. In the former, the first step is a C-Cl bond scission, which is not influenced by oxygen. Chlorine is converted into hydrochloric acid. For monochlorophenols, the position of the chlorine on the ring strongly influences the transformation. In the molecular form, 2-chlorophenol is converted into pyrocatechol. In the anionic form however, it is reduced in a cyclopentadienic acid which dimerizes according to a Diels-Alder reaction. The irradiation of 3-chlorophenol leads to resorcinol whatever the pH. This would appear to suggest a photohydrolysis mechanism. With 4-chlorophenol, the photochemical conversion is not so specific. Hydroquinone is formed (mainly in aerated solution), along with polyphenolic oligomers. A radical mechanism is proposed.     

Surrogate compounds for dioxins in incineration. A review

Dioxins, formed in any combustion process where carbon, oxygen and chlorine are present, are a subject of major interest due to their toxicity. Their measurement is very expensive and time consuming. In order to optimize the combustion process, on-line measurements of pollutants must be done. The use of surrogate compounds instead of dioxins seems to be a convenient method to overcome the aforementioned drawback. This work is a review of the literature dedicated to the possible surrogate compounds for dioxins; the relationships found were systematized and, in some cases, the available experimental data were used and original correlations were found. Correlation of surrogate compounds was found to be: incinerator, feedstock, process and sample point location specific. Amongst the possible surrogates, chlorobenzenes show real possibilities to be good indicators for toxic equivalent factors.     

Impact assessment of climate change on farming systems in the South Mediterranean area: a Tunisian case study

Regional Environmental Change - This study considers a quantitative approach for assessing the performance of Tunisian farming systems to face climate change. It is based on the resilience concept...