Some Chemical Aspects Of Kraft Odor Control

The principal sources of odor in the kraft pulping process are the digester, the direct evaporator, and the recovery furnace. Control of odor from the digester requires the confinement of the noncondensable gases and their destruction by chlorination, burning, or by some other means. Control of odor from the direc’ evaporator depends on efficient black liquor oxidation. The recovery furnace, which potentially can be the worst source of air pollution, must be operated properly within its rated capacity. The chemistry of various control measures is discussed.     

A multi-scale study of Orthoptera species richness and human population size controlling for sampling effort

Recent large-scale studies have shown that biodiversity-rich regions also tend to be densely populated areas. The most obvious explanation is that biodiversity and human beings tend to match the distribution of energy availability, environmental stability and/or habitat heterogeneity. However, the species–people correlation can also be an artefact, as more populated regions could show more species because of a more thorough sampling. Few studies have tested this sampling bias hypothesis. Using a newly collated dataset, we studied whether Orthoptera species richness is related to human population size in Italy’s regions (average area 15,000 km²) and provinces (2,900 km²). As expected, the observed number of species increases significantly with increasing human population size for both grain sizes, although the proportion of variance explained is minimal at the provincial level. However, variations in observed Orthoptera species richness are primarily associated with the available number of records, which is in turn well correlated with human population size (at least at the regional level). Estimated Orthoptera species richness (Chao2 and Jackknife) also increases with human population size both for regions and provinces. Both for regions and provinces, this increase is not significant when controlling for variation in area and number of records. Our study confirms the hypothesis that broad-scale human population–biodiversity correlations can in some cases be artefactual. More systematic sampling of less studied taxa such as invertebrates is necessary to ascertain whether biogeographical patterns persist when sampling effort is kept constant or included in models.     

Benthic-pelagic coupling in frontal system areas of the Northern Adriatic Sea: Analysis of the carbon budgets

Sediment samples were collected between 1996 and 1998 during 4 cruises in the northern sector of the Adriatic Sea, facing the Po River outflow. In each sampling period, after identification of the front line, a grid of 6 sampling stations was selected in order to cover: the coastal area (largely affected by river waters), the inner and outer front areas, and the offshore waters. The biochemical composition of sedimentary organic matter (OM, lipids, proteins, carbohydrates and photosynthetic pigments) and enzymatic activity rates were studied to provide information on the potential organic matter turnover. Tentative estimates of the organic carbon budgets (input/production versus requirement by benthic consumers) are presented. Benthic carbon requirements, estimated from bacterial plus meiofaunal secondary production, was high (897 r mg r C r m m 2 r d m 1 ). OM concentrations in the Northern and Middle Adriatic Sea displayed high values, proteins being dominant, thus suggesting inputs of freshly produced material to the sea floor. OM turnover was generally rapid (11-30 r d m 1 ) and higher during summer. The uncoupled enzymatic rates ( i.e. faster protein than carbohydrate mobilisation in February, 1997) determined a decrease of the OM quality that plays an important role in biogeochemical cycles and OM diagenesis, limiting bacterial secondary production and sedimentary organic carbon utilisation. These data suggest that the efficiency of the system in the transfer of energy through the food web is generally higher in summer, especially during mucilage production.     

Changes in Microbial Community Structure and Soil Biological Properties in Mined Dune Areas During Re-vegetation

The aim of this study was to describe the impact of re-vegetation on the restoration of microbial community structure and soil microbiological properties in sand dunes that had been affected by mining activity. Soil samples were collected during the dry and rainy seasons from a chronosequence (1, 9, 21 years) of re-vegetated dunes using a single preserved dune as a reference. The composition of the fatty acid methyl esters and soil microbial properties were evaluated. The results showed that the changes in microbial community structure were related to seasonal variations: biomarkers of Gram-positive bacteria were higher than Gram-negative bacteria during the dry season, showing that this group of organisms is more tolerant to these stressful conditions. The microbial community structure in the natural dune was less affected by seasonal variation compared to the re-vegetated areas, whereas the opposite was observed for microbiological properties. Thus, in general, the proportion of saprobic fungi was higher in the natural dune, whereas Gram-negative bacteria were proportionally more common in the younger areas. Although over time the re-vegetation allows the recovery of the microbial community and the soil functions, these communities and functions are different from those found in the undisturbed areas.