Review articles: Tankships in the marine environment

This report gives an inside view on discussions held at the headquarters of the International Maritime Organization, the United Nations agency concerned with maritime safety and the prevention of pollution from ships. Marine environmental protection regulations and their historical development are presented and discussed. The regulative measures that have been taken under the responsibility of this organization during the last decades to reduce accidental and operational discharge from tankships have achieved success although the marine environment is still suffering. Those standards which will come into force will further reduce the risks of accidental pollution. The report summarizes aspects beyond issues of environmental science which have to be analysed in order to reduce the impact of tankships on the marine environment. The report ends with the thesis that safer ships and improved occupational conditions on board are prerequisites for cleaner seas.     

常压非平衡态等离子体降解挥发性烃类污染物

采用无声放电产生的非平衡态等离子体,对含有易挥发性有机化合物正己烷、环己烷、苯和甲苯4种典型的烃类废气的空气进行了处理．结果表明,对于一个大气压下正己烷含量（体积分数）为0．26％、0．79％、13％的宁气,在12kV的电压下放电ls,正己烷的降解率分别为88％、81.8％、64．9％．含有环己洗、苯及甲苯浓度为0．26％的空气,在同样的条件下,放电ls后,环己烷、苯及甲苯降解率分别为87．4％、8l％和70．3％,其主要降解产物为CO₂和H₂O．还研究了污染物浓度与氧含量对非平衡态等离子体法降解挥发性烃类污染物的影响     

Parental investment, potential reproductive rates, and mating system in the strawberry dart-poison frog, Dendrobates pumilio

We studied the effect of relative parental investment on potential reproductive rates (PRRs) to explain sex differences in selectivity and competition in the dart-poison frog Dendrobates pumilio. We recorded the reproductive behavior of this species in a Costa Rican lowland rainforest for almost 6 months. Females spent more time on parental care than males, and `time out' estimates suggest that PRRs of males are much higher than than those of females, rendering females the limiting sex in the mating process. Males defended territories that provide suitable calling sites, space for courtship and oviposition, and prevent interference by competitors. Male mating success was highly variable, from 0 to 12 matings, and was significantly correlated with calling activity and average perch height, but was independent of body size and weight. Estimates of opportunity for sexual selection and variation in male mating success are given. The mating system is polygamous: males and females mated several times with different mates. Females were more selective than males and may sample males between matings. The discrepancy in PRRs between the sexes due to differences in parental investment and the prolonged breeding season is sufficient to explain the observed mating pattern i.e., selective females, high variance in male mating success, and the considerable opportunity for sexual selection. Received: 9 June 1998 / Received in revised form: 27 March 1999 / Accepted: 3 April 1999     

Mating system evolution in response to search costs in the speckled wood butterfly, Pararge aegeria

A general and intuitive prediction from models of mate preference is that when the cost of searching for mates increases, individuals should become less choosy. Here, we test this prediction by comparing the mating propensity of females in two populations of the butterfly Pararge aegeria. The populations originated from southern Sweden and Madeira and due to different adult emergence patterns throughout the year, the average density of males per female is likely to be lower on Madeira. Therefore, we expected that the cost of searching should be greater on Madeira and, consequently, that the Madeiran females should be less choosy. In line with predictions, the Madeiran females mated significantly sooner after the first interaction with males than did females from southern Sweden. This difference may reflect a weaker preference for territorial males over non-territorial patrollers in the Madeiran population, because of the greater costs of searching. The Madeiran females also showed a shorter time lag between mating and the start of oviposition. We discuss this unexpected result and propose that the same mechanism could also explain this population difference, i.e. different costs of searching for suitable host plants. Both search processes are fundamental for female reproductive success and we find it plausible that they can be generalised into the same theory of optimal search behaviour. Received: 14 May 1998 / Accepted after revision: 13 December 1998     

A trail pheromone component of the African stink ant, Pachycondyla (Paltothyreus) tarsata Fabricius (Hymenoptera: Formicidae: Ponerinae)

Summary. The African stink ants (Pachycondyla tarsata) lay recruitment trails with secretions from sternal glands. The glandular secretions consist of 10 compounds, 9 of which have been chemically identified. One of the substances, 9-heptadecanone, elicits trail following behavior in P. tarsata workers that have before been stimulated by a sucessful scout ant. Received 7 August 1998; accepted 24 November 1998.     

Within-plant allocation of a chemical defense in Secale cereale. Is concentration the appropriate currency of allocation?

Summary. The among-leaves allocation of DIBOA, a hydroxamic acid associated with plant resistance, in the shoot of rye (Secale cereale) was evaluated over the vegetative development of the plant. The appropriateness of using the concentration of secondary metabolites, DIBOA in this case, as the parameter to evaluate defense allocation in plants is discussed. Both biological and statistical arguments are put forward to suggest that allocation of chemical defenses should refer to absolute content and not to concentration. Results showed that leaf age was significantly linked to leaf concentration of DIBOA, young leaves having higher concentrations. In contrast, leaf content of DIBOA, our proposed currency of allocation, was not significantly higher in younger leaves. Furthermore, a regression analysis showed that the DIBOA content of leaves was better explained by the leaf relative biomass (proportion of shoot biomass) than by leaf biomass itself. It is suggested that, rather than leaf age, leaf relative biomass is the major factor determining DIBOA allocation in rye shoots. It is proposed that studies addressing within-plant defense allocation should use chemical defense content as the currency, emphasizing the major factors driving this process and its underlying mechanisms. Likewise, it is proposed that studies aiming at characterizing optimal patterns of plant defense should use chemical defense concentration as the currency, and be accompanied by evaluations of the actual resistance against herbivores of the plant parts analyzed, together with the effect on plant fitness. Received 19 February 1999; accepted 28 April 1999.     

Verhalten von PAK im system boden/Pflanze

The results of lysimeter experiments conducted since 1991 dealing with the behavior of PAH in soil/plant systems demonstrate that the PAH pollution to cultivated plants may be caused by both atmospheric deposition and by the soil-to-plant transfer observed in contaminated sites. In the latter, a “direct contamination” of plant surfaces with PAH-loaded soil particles and the subsequent PAH turnover by desorption/adsorption processes is seen to dominate—at least for the most relevant PAHs toxic to humans, benzo(a)pyrene and dibenz(a,h)anthracene. Leafy vegetables growing close to the soil surface are therefore endangered most by a PAH contamination of the soil. The soil-to-plant transfer via “direct contamination” can be reduced to a high degree by covering the contaminated soil with different mulch materials. Systematic PAH transfer via root uptake could not generally be observed. From the reported results, a trigger value in the soil of 1 mg·kg^?1 for benzo(a)pyrene is proposed to make a judgement on PAH contaminated soils with regard to the soil-to-plant transfer pathways. Soils with excessive concentrations of benzo(a)pyrene demand special attention when considering the recommendations for the growth and consumption of cultivated vegetables. The “soil”as well as the “deposition pathways” must be integrated into a complete risk assessment of locations with food plant production, especially in urban areas.     

Effects of Amazonian flying rivers on frog biodiversity and populations in the Atlantic rainforest

Given the speed at which humans are changing the climate, species with high degrees of endemism may not have time to avoid extinction through adaptation. We investigated through teleconnection analysis the origin of rainfall that determines the phylogenetic diversity of rainforest frogs and the effects of microclimate differences in shaping the morphological traits of isolated populations (which contribute to greater phylogenetic diversity and speciation). We also investigated through teleconnection analysis how deforestation in Amazonia can affect ecosystem services that are fundamental to maintaining the climate of the Atlantic rainforest biodiversity hotspot. Seasonal winds known as flying rivers carry water vapor from Amazonia to the Atlantic Forest, and the breaking of this ecosystem service could lead Atlantic Forest species to population decline and extinction in the short term. Our results suggest that the selection of morphological traits that shape Atlantic Forest frog diversity and their population dynamics are influenced by the Amazonian flying rivers. Our results also suggest that the increases of temperature anomalies in the Atlantic Ocean due to global warming and in the Amazon forest due to deforestation are already breaking this cycle and threaten the biodiversity of the Atlantic Forest hotspot.     

Scenario simulation of water security in China

Umited water resources, increasing demand, low use efficiency, and serious pollution result in severe water resource difficult in China. The evaluation of addressing water problems and the search for effective countermeasures that ensure sustainable water use are key to China‘ s sustainable development. The “compound water security“ consists of food security, life security, environmental security, and economic security. By establishing a conceptual model, the water security of China has been simulated in terms of four scenarios called BAU(the business-as-usual scenario), TEC(the technology and economics scenario), IVL(the institution, values, and lifestyles scenario) and TSD(toward sustainable development) in this paper. The results indicated that water crises, especially water shortages, are being experienced now and will continue to do so for a relatively long time in China and that it is possible to reach a basic balance between supply and demand of water and grain under the TSD developing pattern by a series of approaches including technological innovation, policy adjustments, and behaviour inducement.     

German drinking water regulations,pesticides, and axiom of concern

The limit value of 0.1 μg/liter for “substances used in plant treatment and pest control including their main toxic degradation products” (PBSM) established in the German Drinking Water Regulations (Trinkwasserverordnung) serves comprehensively to protect drinking water from unexpected toxicological risks and thus corresponds to theaxiom of concern (Besorgnisgrundsatz) contained in §11,2 of the Federal Communicable Disease Control Act (Bundesseuchengesetz), which is an essential cornerstone of the Drinking Water Regulations. Furthermore, precautionary values that are specific to the particular substance and near the valid limit can be found for about 10% of all registered active substances. The goal of the PBSM Recommendations of the Federal Health Office (BGA) issued in July 1989 is to preserve and restore groundwater and drinking water through measures to be taken by the causal party, while reducing consumer health risks to the greatest extent possible. The EC commission's drawbacks on these recommendations and the imminent EC-wide directive for the uniform registration of pesticides being based solely on Article 43 of the European Treaty would seriously endanger this goal. Therefore, a situation threatens in Europe similar to that in the United States, where at least 18 active ingredients have been detected in groundwater in concentrations of up to 1000 times the toxicologically established limits for drinking water. This article appeared first in the German journal?ffentliches Gesundheitswesen 52(8–9); 372–379, 1990. We thank the editor (Georg Thieme Verlag, D-7000 Stuttgart) for the kind permission to publish this slightly revised English version inEnvironmental Management.