Variation of nutrient and metal concentrations in aquatic macrophytes along the Rio Cachoeira in Bahia (Brazil)

The use of cuprous fungicides in cocoa production in the southern part of the state of Bahia (Brazil) for decades has caused an accumulation of copper in various components of the cocoa plantations, and a contamination of regional freshwater ecosystems is suspected. Urban and industrial sources are supposed to contribute to water pollution and eutrophication of the Rio Cachoeira, the main river in this region. In order to study the metal contamination and nutritional status of this freshwater ecosystem, samples of the aquatic macrophytes Eichhornia crassipes and Pistia stratiotes were collected at seven sites along the river course. The samples were analysed for their copper, aluminium, chromium, nitrogen and phosphorus concentrations. The levels of heavy metals increased in the downstream direction, particularly in the roots of water hyacinth. A dramatic increase of nitrogen and phosphorus concentrations in water as well as in plant tissues was found in samples collected downstream from the city of Itabuna. Metal input and eutrophication were attributed to agricultural, industrial and urban sources in the region. Biomonitoring of the water quality using aquatic macrophytes as accumulative indicator plants is recommended in addition to chemical water analyses.     

The Society for Environmental Geochemistry and Health Tenth European Meeting University of Edinburgh April 12–15, 1992

The Society for Environmental Geochemistry and Health Tenth European MeetingUniversity of Edinburgh April 12–15, 1992     

Dynamics of state mining enterprises during the 1980s and the outlook for the 1990s

This paper examines the evolution of the control by the state of mining and smelting from 1975 to 1989. In 1950, there was little state-owned mining capacity outside the centrally planned economies. A wave of nationalizations of mine assets swept over the developing countries in the late 1960s and early 1970s. State control continued to rise, in developing countries as well as in the developed market economy countries, until the mid-1980s, when the trend reversed. At present some 20% of Western world mineral production is state controlled. The level of control is highest for those minerals mined mainly in the developing countries, and lowest for those minerals mined mainly in the developed market economy countries. The current trend is toward privatization of state-owned mining enterprises in developed countries and it is expected that as the 1990s progress, privatization of such enterprises will also begin to take place in developing countries.     

Political commitment to CO<Subscript>2</Subscript> capture and storage: evidence from government RD&;D budgets

For CO₂ capture and storage (CCS) to succeed as a mitigation strategy, political commitment is one of several prerequisites. This article offers an appraisal of political commitment to a CCS strategy among high-income countries in Europe and North America: Which governments are committed, and what particular interests and concerns do they seek to accommodate by supporting CCS? In order to answer these questions, new data are reported on government CCS research, development and demonstration (RD&;D) budgets. RD&;D budgets divided by GDP is used as an indicator of political commitment, and explanations are sought for cross-national differences. The analysis shows that fossil fuels reserves and extraction within a country has a very strong bearing on funding levels. Likely explanations include the potential for combining CCS with enhanced resource recovery. All large economies (population >50 million) have a funding program. The smaller states that provide funding (Norway, Canada, the Netherlands) have the highest funding levels relative to GDP. These findings suggest that high-income petroleum producing countries are likely to be leaders in promoting CCS and a favorable regulatory environment. The fact that all large, high-income countries in the two regions now display some interest in CCS further improves its political outlook.     

Adaptive significance of sex ratio adjustment in semifree-ranging Barbary macaques (Macaca sylvanus) at Salem

Summary New data on the secondary sex ratio in semi-free-ranging Barbary macaques at Salem confirm the observation that the offspring of high-ranking females in this colony are biased towards sons while the offspring of low-ranking females are biased towards daughters. Analysis of interbirth intervals yielded no consistent differences in the relative costs of rearing male and female offspring for either high- or low-ranking females. Survivorship to adulthood of male and female offspring born to mothers of all rank classes was remarkably high, and there was no indication that juvenile females of low-ranking mothers face any greater risk. Daughters of high- and low-ranking mothers showed no substantial differences in reproductive success, while mating and probably reproductive success of sons seemed to be dependent on maternal rank, at least at the beginning of their reproductive career. The results suggest that variation in sex ratio does increase parental fitness. Offprint requests to: A. Paul     

Tube-worm-sediment relationships in populations of Pectinaria gouldii (Polychaeta: Pectinariidae) from Barnegat Bay,New Jersey,USA

Pectinaria gouldii (Verrill), which lives for 1 year in Barnegat Bay, New Jersey, constructs over its lifetime a conical tube of increasingly large sand grains, regardless of surrounding sediment characteristics. However, the rate of increase of mean grain size of the tube and the population density of the worm vary with sediment type. The distribution of this species is limited by sediment composition. Worms of equal length will always have equal anterior tube apertures, although the thickness of the tube walls may be unequal. Tube surface-area, worm dry weight, and tube weight all increase as a power function of tube length. The conical shape and increasing mass of the tube impose an upper limit to worm growth, but do not interfere with worm mobility.     

Tiefentschwefelte Kraftstoffe

In recent years, much attention has been given to the desulphurization of fuels like diesel oil and gasoline, since exhaust gases containing SOx cause air pollution and acid rain. Moreover, a lower sulphur content of fuels would allow the use of new engines and catalytic systems for the reduction of CO, particle and NOx-emissions, and a more efficient fuel consumption. The S-level in fuels is presently limited in Germany for gasoline and diesel oll to 150 ppm and 350 ppm, respectively. In 2005 the level will be decreased Europe-wide for all vehicle-fuels down to 50 ppm; in some countries, fuels are or will be on the market with even less sulphur. The current technology of hydrodesulphurization (heterogeneous, catalyzed hydrorreating of organic sulphur compounds) can desulphurize quite adequately down to today’s S-level. The process, however, is limited for the production of ultra-low sulphur fuels, and the expenses (pressure, reactor size, investment costs, energy consumption, specific active catalysts) are high to meet future requirements. alternative processes, which are not limited to hydrotreating, are therefore desirable. Beside an overview about hydrotreating, this paper presents two quite different alternatives: Extraction of sulphur compounds by ionic liquids and the synthetic production of S-free fuels from natural gas by Fischer-Tropsch-synthesis. Ionic liquids (ILs) are low melting (<100°C) salts which represent a new class of non-molecular, ionic solvents. In the experiments presented, extraction of model diesel oils (dibenzothiophene and dodecanthiol in n-dodecane) as well as of a real predesulphurized diesel oil (with about 400 ppm S) were investigated. The results show the excellent and selective extraction properties of ILs for organic sulphur compounds, especially with regard to those compounds which are very difficult to remove by common hydrodesulphurization. As expected, the desulphurization by extraction is much more complicated in case of real diesel oil (compared to a model oil) due to its complex chemical composition including many different sulphur compounds and other impurities like organic nitrogen and metal-compounds. Nevertheless, the results with pre-desulphurized diesel oil are also very promising. So, extraction of sulphur components by ILs is a new approach for deep desulphurization of diesel oil. The application of very mild process conditions (low pressure and temperature) in comparison to traditional hydrotreating is an additional advantage of this new concept. An alternative to today’s fuels based on crude oil is the production of gasoline and diesel oil from natural gas (or other fossil fuels like coal) by Fischer-Tropsch-synthesis (FTS). The products like diesel oil are completely free of sulphur and other impurities like nitrogen and metal compounds. Although several FTS-processes have been investigated and developed, and some processes are already running on a technical scale, a real breakthrough was not obtained up to now. The production costs of these capital-intensive processes are probably above the breakeven point, at least at today’s oil price. In this paper, a ‘lowcost’ process is discussed, which is based on nitrogen-rich syngas. In contrast to classical FTS-processes with nitrogen-free syngas, the investment costs are probably lower: The syngas is produced by partial oxidation with ait, which eliminates the need of an air separation plant, while a process with nitrogen-rich syngas does not utilize a recycle loop and a recycle compressor.     

Seasonal nestmate recognition in the ant Formica exsecta

Under favorable conditions, the mound-building ant Formica exsecta may form polydomous colonies and can establish large nest aggregations. The lack of worker aggression towards nonnestmate conspecifics is a typical behavioral feature in such social organization, allowing for a free flux of individuals among nests. However, this mutual worker toleration may vary over the seasons and on spatial scales. We studied spatio-temporal variation of worker–worker aggression within and among nests of a polydomous F. exsecta population. In addition, we determined inter- and intracolony genetic relatedness by microsatellite DNA genotyping and assessed its effect on nestmate recognition. We found significant differences in the frequency of worker exchange among nests between spring, summer, and autumn. Moreover, we found significant seasonal variation in the level of aggression among workers of different nests. Aggression levels significantly correlated with spatial distance between nests in spring, but neither in summer nor in autumn. Multiple regression analysis revealed a stronger effect of spatial distances rather than genetic relatedness on aggressive behavior. Because nestmate discrimination disappeared over the season, the higher aggression in spring is most plausibly explained by cue intermixing during hibernation.     

Dominance,kinship and reproductive value in female Barbary macaques (Macaca sylvanus) at Affenberg Salem

Summary In the course of a long-term study on social organization of semi-free-ranging Barbary macaques (Macaca sylvanus) at Affenberg Salem, genealogical and cross-genealogical rank relations of adult and adolescent females in three social groups were studied. Female rank was highly dependent on maternal rank, but the process of rank acquisition was also affected by age/size differences between members of different families. Mother-daughter rank reversal was rare, but all old, postreproductive matriarchs were outranked by their adult daughters. Contrary to findings of other studies on macaques, younger sisters seldom outranked older sisters. There was no genealogy with a strict age-inversed hierarchy among adult sisters as described for rhesus and Japanese macaques. Rank reversals between sisters were more frequent in genealogies with old or dead matriarchs, in large clans, and in dyads with an age difference of more than 1 year, indicating that demographic variables influence intra-genealogical dominance relations. It is suggested that close, long-lasting relationships between sisters and mothers and doughters impede rank reversals. Previous evolutionary models of female dominance relations in primates that explain rank relations among sisters as a function of their reproductive value or as a strategy of the mother to maintain her own status are not supported by the data. The results of this and other studies indicate that rank reversal between sisters is not as universal for Old World monkeys, or even macaques, as frequently proposed.