Potential impact model to assess agricultural pressure to landscape ecological functions

Conservation and protection of soil and water resources and visual aspects of landscape, as well as the promotion of biodiversity, are some of the central tasks of environmental policy development and social politics in the future. One of the main questions is: ‘which agricultural systems are able to guarantee sustained resource-conserving land use?’ Based on the ecological risk concepts of the 1970s and 1980s, a potential impact model was developed using a universal assessment algorithm derived from fuzzy logic. The model estimated the potential impact of agricultural land use on ecosystem function using a few resource indicators. Intervention intensities of agricultural land-use are set in relation to site conditions and aggregated for each of several defined potential impact categories. The interpretation with respect to risk and the calculation of potential impact values are explained.     

The Probability of a Horizontal Gene Transfer from Roundup Ready® Soybean to Root Symbiotic Bacteria: A Risk Assessment Study on the GSF Lysimeter Station

The gene transfer from glyphosate tolerant soybean to Bradyrhizobium japonicum was evaluated in a free-air lysimeter experiment under natural conditions and increasing selection pressure, to monitor for the probability of horizontal gene transfer (HGT). A large volume lysimeter study that offers conditions comparable to normal farming was conducted in 2004 and 2005 with Roundup Ready® (RR) soybean and Roundup® application according to agricultural practice. Analysis of nodules showed, as expected, the presence of the transgenic 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). However, in bacteroids that were isolated from nodules and then cultivated for several rounds in the presence of high levels of glyphosate, the EPSPS gene could no longer be detected. This indicates no stable HGT transfer of the whole EPSPS gene under field conditions.     

Degradation of poly(3-hydroxybutyrate), PHB,by bacteria and purification of a novel PHB depolymerase fromComamonas sp.

Bacteria capable of growing on poly(3-hydroxybutyrate), PHB, as the sole source of carbon and energy were isolated from various soils, lake water, activated sludge, and air. Although all bacteria utilized a wide variety of monomeric substrates for growth, most of the strains were restricted to degrade PHB and copolymers of 3-hydroxybutyrate and 3-hydroxyvalerate, P(3HB-co-3HV). Five strains were also able to decompose a homopolymer of 3-hydroxyvalerate, PHV. Poly(3-hydroxyoctanoate), PHO, was not degraded by any of the isolates. One strain, which was identified asComamonas sp., was selected, and the extracellular depolymerase of this strain was purified from the medium by ammonium sulfate precipitation and by chromatography on DEAE-Sephacel and Butyl-Sepharose 4B. The purified PHB depolymerase was not a glycoprotein. The relative molecular masses of the native enzyme and of the subunits were 45,000 or 44,000, respectively. The purified enzyme hydrolyzed PHB, P(3HB-co-3HV), and—at a very low rate—also PHV. Polyhydroxyalkanoates, PHA, with six or more carbon atoms per monomer or characteristic substrates for lipases were not hydrolyzed. In contrast to the PHB depolymerases ofPseudomonas lemoignei andAlcaligenes faecalis T₁, which are sensitive toward phenylmethylsulfonyl fluoride (PMSF) and which hydrolyze PHB mainly to the dimeric and trimeric esters of 3-hydroxybutyrate, the depolymerase ofComamonas sp. was insensitive toward PMSF and hydrolyzed PHB to monomeric 3-hydroxybutyrate indicating a different mechanism of PHB hydrolysis. Furthermore, the pH optimum of the reaction catalyzed by the depolymerase ofComamonas sp. was in the alkaline range at 9.4.     

Elimination of Pentachlorobiphenyls by Nereis virens (Polychaeta) in the Laboratory and the Marine Environment

Fifty sandworms, Nereis virens, were maintained in a closed aquarium system with continuous charcoal filtration at 12°C and 27.6‰ S. They were dosed orally for 10 consecutive days with a mixture of three pentachlorobiphenyls: 35 ng 2,4,6,2',4'-pentachloro[U-¹⁴C]biphenyl, 106 ng 2,4,5,2',5'-pentachlorobiphenyl, and 106 ng 2,3,4,2',5'-pentachlorobiphenyl per g of Nereis virens per day. At the end of the dosing period the accumulated compounds were measured in 5 worms, the remaining 45 specimens were divided into three groups for determining the PCB elimination under different conditions for 14 to 26 weeks: in the laboratory with feeding, in the laboratory without feeding, and in a cage moored in the Weser estuary.

The accumulation percentages for these PCB compounds were 41, 26 and 4% respectively. Times for the initial 50% decrease t_e50 were 4.4, 2.8 and 1.9 weeks respectively, and appeared the same in all three experimental groups. However, in the laboratory experiments the metabolites of the ¹⁴C-labelled compound amounted to ∼60%, compared to the field experiment with ∼30%. This extended the t_e50 for ¹⁴C activity (metabolites included) to ∼9 weeks in the laboratory experiments.     

CDM Projects under the Kyoto Protocol: A Methodology for Sustainability Assessment – Experiences from South Africa and Uruguay

Under the Clean Development Mechanism (CDM) of the Kyoto Protocol, industrialised countries may finance greenhouse gases mitigation projects in developing countries. The Kyoto Protocol explicitly requires that the CDM shall assist developing countries to achieve sustainable development. However, a clear definition of sustainability for CDM projects is still debatable. MATA-CDM (Multi-Attributive Assessment of CDM Projects) is an approach that facilitates a quantitative assessment of potential projects regarding their contribution to sustainable development. This paper presents applications of MATA-CDM in two different countries. In South Africa, the application was done mainly for academic and demonstrative purposes, whereas in Uruguay it was implemented together with the responsible Designated National Authority (DNA). The work in both countries included the selection of sustainability criteria and measurable indicators. Experts weighted the criteria using personal interviews and a multi-stakeholder workshop. This method was applied to three potential CDM projects in South Africa and one in Uruguay. Results show that under the conditions of this study, the MATA-CDM approach yet fails to yield a perfect quantitative overall sustainability assessment of CDM projects but that several findings could be useful to further develop the approach with the aim to translate the vague term sustainable development to a mainstream project level. Valuable experience was in particular collected with different stakeholder processes to perform criteria weighting.