Effects of nitrogen and phosphorus limitation on the activated sludge biomass in a kraft mill biotreatment system.

Unlike wastewater, pulp and paper mill effluents are generally severely deficient in bioavailable nitrogen and phosphorus. The influence of nitrogen and phosphorus limitations on steady-state or typical pulp and paper mill activated sludge floc properties and performance was studied using a bioreactor-fed synthetic raw mill effluent and seeded with mill activated sludge. Limitation of either nitrogen or phosphorus decreased growth, five-day biochemical oxygen demand, and suspended solids removal. Nitrogen limitation greatly enhanced activated sludge floc poly-beta3-hydroxybutyrate (PHB), but not carbohydrate or extracellular polymeric substances (EPS). In contrast, phosphorus limitation increased total floc carbohydrate and EPS, but not PHB. The flocs showed little ability to store either nitrogen or phosphorus. Nitrogen limitation, but not phosphorus limitation, produced much more negative net floc surface charge, increasing fines, while phosphorus limitation, but not nitrogen limitation, increased the floc bound water content and surface hydrophobicity and decreased fines.     

Indigenous knowledge informing management of tropical forests: the link between rhythms in plant secondary chemistry and lunar cycles

This research used knowledge of the indigenous practice of timing nontimber forest product harvest with the full moon to demonstrate that chemicals controlling the decomposition rate of foliage fluctuate with the lunar cycle and may have developed as a result of plant-herbivore interactions. Indigenous knowledge suggests that leaves harvested during the full moon are more durable. Palm leaves harvested during the full moon had higher total C, hemicellulose, complex C and lower Ca concentrations. These chemical changes should make palm leaves less susceptible to herbivory and more durable when harvested during the full moon. This study proposes a mechanism by which plants in the tropics minimize foliage herbivory and influence the decomposition rates of senesced leaves and their durability, especially during the full moon. This research supports the need to use natural life cycles in managing forests and provides a scientific basis for an indigenous community's harvesting practice.     

Application of the Braun-Blanquet cover-abundance scale for vegetation analysis in land development studies

To document environmental impact predictions for land development, as required by United States government regulatory agencies, vegetation studies are conducted using a variety of methods. Density measurement (stem counts) is one method that is frequently used. However, density measurement of shrub and herbaceous vegetation is time-consuming and costly. As an alternative, the Braun-Blanquet cover-abundance scale was used to analyze vegetation in several ecological studies. Results from one of these studies show that the Braun-Blanquet method requires only one third to one fifth the field time required for the density method. Furthermore, cover-abundance ratings are better suited than density values to elucidate graphically species-environment relationships. For extensive surveys this method provides sufficiently accurate baseline data to allow environmental impact assessment as required by regulatory agencies.     

Sexual selection favours small and symmetric males in the polygynous greater sac-winged bat Saccopteryx bilineata (Emballonuridae, Chiroptera)

We investigated how morphological traits of territorial males in the polygynous bat Saccopteryx bilineata were related to their reproductive success. Because of the frequency of aerial courtship displays and defence manoeuvres, and the high energetic costs of flight, we expected small and symmetric males to be better able to court females on the wing and to monopolize copulations with females in their harems. We predicted that small and symmetric males would sire more offspring within the colony and a larger portion of the young born within their harem than large or asymmetric males. We measured size and fluctuating asymmetry of 21 territorial males and analysed their reproductive success in 6 offspring cohorts (n=209 juveniles) using 11 microsatellite loci. As predicted, small and symmetric males had, on average, a higher reproductive success in the colony than large and asymmetric males. The percentage of young sired by males within their harem increased as males decreased in size, but was not influenced by fluctuating asymmetry. As fluctuating asymmetry of males correlated with their reproductive success within the colony but not within their harems, we infer that fluctuating asymmetry is probably related to female choice, whereas male size is probably important for harem defence on the wing.Communicated by G. Wilkinson     

A Comparison of the Size Distribution of Particulates Emitted from Air,Mechanical, and Steam Atomized Oil Fired Burners

Particulate size distributions were obtained in the effluent gases from three steam generating boilers of a power station employing mechanical, steam, and air systems for heavy fuel atomization. Samples were obtained with an eight-stage cascade impactor. The air atomized burner produced the lowest particulate loading, the greatest percentage of particulates by weight in the submicron range, and particulates with the lowest combustible content.     

Global weapons' fallout 137Cs in soils and transfer to vegetation in south-central Chile

The contamination and depth distribution of 137Cs in soil due to the fallout from atmospheric weapons' tests were measured at 29 sites in the 9th and 10th administrative regions in Chile located in the 40 degrees latitude in the southern hemisphere. The depth distribution in most of the sites follows no systematic pattern in the upper few centimetres, but below this depth an exponential decline could be deduced. The calculated relaxation depth appears to be a good indicator for estimating the long-term 137Cs distribution in these soil profiles. It ranges from 4.4 +/- 1.9 cm in Palehumults to 8.4 +/- 4.4 and 9.7 +/- 5.1 cm in Hapludands and Psamments, respectively. For these soil types the value for the relaxation depth tends to increase with decreasing clay content and increasing volume of coarse pores. 137Cs activity densities at the selected sites ranged from 450 to 5410 Bq m(-2) and correlate significantly (r = 0.791) with the mean annual rainfall rate of the sampling sites. 137Cs concentration ratios of prairie plants/soil were found to be in the range 0.008-2.3 and could be related to relaxation depths in undisturbed soils.     

Nachhaltige Entwicklung von Managementstrategien: Multikriterielle Bewertungs- und Entscheidungshilfe-Instrumente im Umweltbereich

Zur Unterstützung von Bewertungs- und Entscheidungsprozessen über die Nachhaltigkeit von Managementstrategien, deren Auswirkungen durch unterschiedlich dimensionierte Indikatoren gemessen werden, gibt es verschiedene mathematische Methoden. In diesem Beitrag werden die Prinzipien dieser sog. multikriteriellen Bewertungs- und Entscheidungshilfeinstrumente beispielhaft anhand einer Auswahl von Strategien für ein Nachhaltiges Wassermanagement vorgestellt, sowie Vor- und Nachteile herausgearbeitet. Es wird gezeigt, dass sich die Verfahren insbesondere in Transparenz, Objektivit?t und durch den Grad an Partizipation durch Akteure z.T. erheblich unterscheiden. W?hrend die Hassediagrammtechnik sich an den naturwissenschaftlich begründbaren Datenmatrix orientiert und somit eine objektive und transparente Bewertung und Datenanalyse liefert, haben Konkordanzanalyse, Nutzwertanalyse, PROMETHEE und AHP ihre St?rken in der M?glichkeit, Akteure bzw. Stakeholder am Entscheidungsprozess partizipieren zu lassen. *** DIRECT SUPPORT *** A00OI029 00003     

Arsenic in ground-water under oxidizing conditions,south-west United States

Concentrations of dissolved arsenic in ground-water in alluvial basins of Arizona commonly exceed 50 g L^–1 and reach values as large as 1,300 g L^–1. Arsenic speciation analyses show that arsenic occurs in the fully oxidized state of plus 5 (As+5), most likely in the form of HAsO4², under existing oxidizing and pH conditions. Arsenic in source areas presumably is oxidized to soluble As before transport into the basin or, if after transport, before burial. Probable sources of arsenic are the sulphide and arsenide deposits in the mineralized areas of the mountains surrounding the basins. Arsenic content of alluvial material ranged from 2 to 88 ppm. Occurrence and removal of arsenic in ground-water are related to the pH and the redox condition of the ground-water, the oxidation state of arsenic, and sorption or exchange. Within basins, dissolved arsenic correlates (P<0.01) with dissolved molybdenum, selenium, vanadium, and fluoride and with pH, suggesting sorption of negative ions. The sorption hypothesis is further supported by enrichment of teachable arsenic in the basin-fill sediments by about tenfold relative to the crustal abundance and by as much as a thousandfold relative to concentrations found in ground-water. Silicate hydrolysis reactions, as defined within the alluvial basins, under closed conditions cause increases in pH basinward and would promote desorption. Within the region, large concentrations of arsenic are commonly associated with the central parts of basins whose chemistries evolve under closed conditions. Arsenic does not correlate with dissolved iron (r = 0.09) but may be partly controlled by iron in the solid phase. High solid-phase arsenic contents were found in red clay beds. Large concentrations of arsenic also were found in water associated with red clay beds. Basins that contain the larger concentrations are bounded primarily by basalt and andesite, suggesting that the iron content as well as the arsenic content of the basin fill may play a role in the occurrence of arsenic in ground-water. Under oxidizing conditions in Arizona, arsenic in ground-water appears to be controlled in part by sorption or desorption of HAsO4² on active ferric oxyhydroxide surfaces.