Modeling habitat suitability for moose in coastal northern Sweden: empirical vs process-oriented approaches

Habitat models may provide viable tools for co-management of large ungulates and forest resources, yet their applicability has not been comprehensively evaluated in managed forest. We examined 2 inherently different approaches to model the relative winter habitat suitability for moose (Alces alces) in the coastal area of northern Sweden. An empirical approach based on GPS positions of 15 female moose was used to scrutinize the assumptions and functional mechanisms of a process-oriented, conceptual approach, based on published material on the species' preferences for habitat components related to food and cover. For both model approaches habitat was described using estimates of forest-stand characteristics based on satellite imagery. The empirical model also included variables relating to topographic properties of the landscape as well as distances to landscape features. The output from both models was a habitat suitability index (HSI) score, enabling the models to be compared with each other. The models showed different results, highlighting the need to include the spatially explicit distribution of environmental variables in future conceptual, process-oriented models.     

Peroxidative degradation of selected PCB: a mechanistic study

The enzyme-induced decomposition and biodegradation of PCB were investigated. 2,5-Dichlorobiphenyl (PCB 9) and 2,2^′,5,5^′-tetrachlorobiphenyl (PCB 52) were used as example compounds to study efficiency and mechanism of the degradation processes. It was found that the application of horseradish peroxidase (HRP) together with defined amounts of hydrogen peroxide removed 90% of the initial concentration of PCB 9 and 55% of the initial concentration of PCB 52 from an aqueous solution after a reaction period of 220 min. Dechlorination was observed as the initial step. Although the metabolites identified were mainly chlorinated hydroxybiphenyls, benzoic acids and non-substituted 1,1^′-biphenyl, some higher chlorinated biphenyl isomers also appeared. The biodegradation of PCB 9 using the white rot fungus Trametes multicolor took about four weeks and reduction was about 80% of the initial concentration. The metabolites produced (dichlorobenzenes, chlorophenols and alkylated benzenes) were not quite the same as those observed upon incubation with HRP.     

Effect of plant growth on copper solubility and speciation in soil solution samples

The effect of plant growth on copper solubility and speciation was studied in a 10-week pot experiment. A copper-tolerant grass variety (Agrostis capillaris L. var. Parys Mountain) was grown in pots that contained either clean (copper-total approx. 30 mg kg(-1)) or copper contaminated soil (copper-total approx. 170 mg kg(-1)) at two pH levels (4.7 and 5.5). Also, similar pots without vegetation were included in the study. Due to the addition of NH(4)NO(3) fertilizer and subsequent nitrification of ammonia to nitrate, soil pH decreased from 4.7 to 3.5 and from 5.5 to 4, respectively. In the planted pots, soil pH recovered faster after depletion of NH(4)(+). This resulted in a decrease in the calcium solution concentrations and an increase in the dissolved organic carbon (DOC) concentrations in the planted pots. However, this was only observed in the clean soil; in the contaminated soil no difference in DOC levels between bare and planted pots was observed. Copper solubility in the contaminated soil was lower in the presence of plants; in the clean soil no differences were observed between the bare and planted pots. In the planted pots, copper activities in solution in both clean and contaminated soils were two orders of magnitude lower than in the bare pots. Copper activities in the non-planted contaminated soil reached potentially toxic levels ([Cu]+/-10(-5) to 10(-6) M) in contrast to the lower levels in the planted pots ([Cu]+/-10(-7) to 10(-10) M). Data and model results show that plant growth improves pH, DOC and calcium in solution to such an extent that both the total dissolved copper concentration and the free metal activity in soils can be reduced. This stresses the potential beneficial role of plants for the immobilization and detoxification of metals in contaminated soils.     

Chlorpyrifos degradation in Turkish soil

Degradation of chlorpyrifos was evaluated in laboratory studies. Surface (0-15 cm) and subsurface (40-60 cm) clay loam soils from a pesticide-untreated field were incubated in biometer flasks for 97 days at 25 degrees C. The treatment was 2 micrograms g-1 [2,6-pyridinyl-14C] chlorpyrifos, with 74 kBq radioactivity per 100 g soil flask. Evolved 14CO2 was monitored in KOH traps throughout the experiment. Periodically, soil subsamples were also methanol-extracted [ambient shaking, then supercritical fluid extraction (SFE)], then analyzed by thin-layer chromatography. Total 14C and unextractable soil-bound 14C residues were determined by combustion. From the surface and subsurface soils, 41 and 43% of the applied radiocarbon was evolved as 14CO2 during 3 months incubation. The time required for 50% loss of the parent insecticide in surface and subsurface soils was about 10 days. By 97 days, chlorpyrifos residues and their relative concentration (in surface/subsurface) as % of applied 14C were: 14CO2 (40.6/42.6), chlorpyrifos (13.1/12.4), soil-bound residues (11.7/11.4), and 3,5,6-trichloropyridinol (TCP) (3.8/4.8). Chlorpyrifos was largely extracted by simple shaking with methanol, whereas TCP was mainly removed only by SFE. The short persistence of chlorpyrifos probably relates to the high soil pH (7.9-8.1).     

Evaluation of sequentially-coupled POP fluxes estimated from simultaneous measurements in multiple compartments of an air-water-sediment system

Bulk atmospheric deposition fluxes, air-water exchange fluxes, particle settling fluxes out of the upper water column, sediment trap fluxes in deep waters, and sediment burial fluxes of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) were simultaneously measured in the Koster Fjord, eastern Skagerak, on the Swedish west coast. The aim of the study was to compare the magnitude and direction of the compound fluxes in the system in order to diagnose key fate processes. The PCB and PAH fluxes via net atmospheric deposition, settling particles out of the surface and through deep waters, as well as into the accreting underlying sediments were shown to be remarkably similar, agreeing within a factor of a few for any given target compound. Fluxes of all PCB and PAH target compounds remained fairly constant with water column depth. Thus there was no evidence for net desorption from sinking particles. The net unidirectional and near balancing of vertical fluxes suggests a net transport of PCBs and PAHs from the atmosphere to the continental shelf sediments in the Koster Fjord, which is consistent with the hypothesis that the shelf sediments are important sinks for these compounds.     

Effects of halone 1301 on Lepidium sativum, Petunia hybrida and Phaseolus vulgaris

Halone 1301 belongs to a group of widely used fire repellants. Although banned in several countries, the production has still not been discontinued, and thus hazards due to use or spill can be expected. The study reports on effects of the halone 1301 on three plant species frequently used for bioindication studies: Lepidium sativum (mouse-ear cress), Phaseolus vulgaris (bush bean) and Petunia hybrida. Plants were exposed to 1 ppbv of the gas in ambient air under controlled conditions for 18 days (L. sativum), and 45 days (P. vulgaris, P. hybrida), respectively. None of the plants showed visible stress symptoms. Chlorophylls in cress and petunia were unaffected whereas in beans significant changes of the photosynthetic pigments were observed. Photosynthesis and gas exchange of bean plants were monitored during the experiment, and a lowering of transpiration was noticed. In all investigated plants, protein contents declined significantly, but despite this reduction, activity of the glutathione S-transferases (GST) increased strongly in bean and petunia. The significance of this reaction as detoxification step is discussed.     

In search of human-associated bacterial pathogens in Antarctic wildlife: report from six penguin colonies regularly visited by tourists

We investigated the potential role of Antarctic tourism in the introduction of human-associated pathogens into Antarctic wildlife. We collected and analyzed 233 fecal samples from eight bird species. The samples were collected at six localities on the Antarctic Peninsula, which often is visited by tourists. Every sample was investigated for pathogens of potential human origin: Campylobacter jejuni, Salmonella spp., and Yersina spp. None of these bacteria was found. Our data suggest that the tourism industry so far has achieved its goal of not introducing pathogens into the Antarctic region. There is, however, an urgent need to further investigate the situation in areas closer to permanent Antarctic settlements.     

Ozone and bean plants: morphology matters

Relationship between leaf morphology and cultivar sensitivity to ozone were established.     

Norway spruce and spruce shoot aphid as indicators of traffic pollution

Two-year-old Norway spruce (Picea abies (L.) Karst) seedlings were exposed to traffic emissions along roadsides with three different traffic densities and speed limits; highway, street and a quiet local road. The responses of the exposed seedlings as a host plant and those of spruce shoot aphid (Cinara pilicornis Hartig) were studied. The concentrations of soluble N and free amino acids, defence chemicals (total phenolics, monoterpenes) were analysed, and aphid growth and reproduction were studied. Along the highway, street and at the local road control site, the atmospheric concentrations of black carbon (BC) and oxides of N (NO(x)) were measured for 1 week during the experiment. The BC data indicate deposition of organic particulate compounds along the highway and street. The NO(x) concentrations along the highway and street showed great diurnal variation, but the average NO(x) concentrations were relatively low. Thus, no changes in N metabolism or growth of the exposed Norway spruce seedlings were found. Along the street, the concentrations of many individual free amino acids, such as proline, as well as total amino acid concentrations, were lower than at the associated control site. Correspondingly, there was also no increase in spruce shoot aphid mean relative growth rate. The aphid reproduction, however, increased along the highway and is suggested to be due to more conducive microclimatic conditions at the exposure site or lack of natural enemies. No changes in defence chemicals (total phenolics, monoterpenes) in relation to the traffic exposure were found. Instead, the microclimatic conditions (temperature, solar irradiation) seemed to affect the concentration of total phenolics.     

14C-dimethoate residues in olive oil during oil processing

An olive tree was treated twice in the field with 14C-dimethoate (237.7 muCi, 2.4 g) and 14C residues were determined in the olive fruits at harvest. The fruits were crushed and pressed to extract the crude oil, then refined by neutralization, bleaching and deodorization. The crude oil contained 14.1% of the total 14C in the olive fruits. Neutralization resulted in a reduction of 14C by about 50% of the total 14C residues in oil. Bleaching and deodorization processes further reduced the 14C residues and the refined oil contained 31.6% (which corresponds to 4.4% of 14C residues of the total 14C in olive fruits) of the total 14C in the crude oil. Industrially extracted crude oil was fortified with 14C-dimethoate at 1.8 mg kg-1 (0.02 muCi) level and subjected to the same refining process. A sharp decrease in the amount of 14C was observed by neutralization and the amount of 14C remaining in the refined oil was about 7.3% of the total 14C in the crude fortified oil. The data suggest that the 14C residues in the aged and the fortified oil amples were not of the same nature. The terminal 14C residue in the refined oil obtained from the field experiment did not contain dimethoate and/or its oxon.