An Environmental Kuznets Curve for N2O emissions in Germany: an ARDL approach

This paper analyses the relationship between nitrous oxide (N₂O) emissions, economic growth, agricultural land used and exports in Germany. We use time‐series data between 1970 and 2012 and the Autoregressive Distributed Lag (ARDL) methodology to test for cointegration in the long run. Results show that there is a quadratic long run relationship between N₂O emissions and economic growth, confirming the existence of an Environmental Kuznets Curve (EKC) for Germany. Agricultural land area affects N₂O emissions positively, whereas exports affect emissions negatively. The turning point is $27,880, which is within the sample and implies that Germany is in the decreasing part of the curve of environmental degradation. The paper shows that, contrary to testing the EKC in less developed countries, mitigation of N₂O emissions does not negatively affect growth in Germany. As such, it is feasible to undertake any conservative policy in order to reduce emissions without major consequences on economic sectors.     

Predictors of concentrations of hexachlorobenzene in human adipose tissue: a multivariate analysis by gender in Southern Spain

Hexachlorobenzene (HCB) was measured in adipose tissue intraoperatively collected from 387 subjects over 16 years old undergoing surgery in two hospitals in Granada (Southern Spain). HCB was quantified in 90.7% of subjects. The concentrations and frequencies of HCB were similar to those reported in adipose tissue samples in other recent European studies. Exposure patterns differed between females and males: higher HCB concentrations were found in females than in males (geometric mean 18.3 vs. 6.8 ng/g, p<0.001). The relationship between HCB concentrations and exposure risk factors was assessed by multivariate analysis stratifying by gender. In men, HCB concentrations were predicted (r(2)=0.45) by age, body mass index (BMI), place of residence, smoking, consumption of fish, chicken and cheese, occupation related to agriculture, and family involvement in construction activities. In women, HCB concentrations were predicted (r(2)=0.50) by age, BMI, consumption of milk and cheese, and occupation related to industry. The finding that women had three-fold higher levels of HCB than the men deserves further investigation.     

Nitrogen and Sulfur Input-Output Budgets in the Experimental and Reference Watersheds, Bear Brook Watershed in Maine (BBWM)

Dry (NH4)2SO4 (1,800 eq-1 ha-1 yr-1) has been applied to the western of two contiguous 10 ha catchments at the Bear Brook Watershed in Maine (BBWM) since November, 1989. The initial rapid and significant response in both S and N in West Bear, compared to the reference East Bear, slowed after three years. Annual S retention of the total experimental treatment decreased from 86 to 34%, with a seven year cumulative retention of 59%. Hydrology influences the export flux of S; S is retained more in dry seasons and dry years. The annual retention of N has decreased from 96 to 81%, with a cumulative retention of 82%. The export of N from the reference watershed has declined from 178 to 23 eq-1 ha-1 yr-1 during the treatment period. The treatment N (as NH4) initially stimulated nitrification, and caused pre-existing N to be lost in runoff, rather than the treatment N. Retention of the treatment N has decreased to approximately 80%. The majority of the retained N is stored in the soil, but the reasons for the decreased flux from the reference watershed are not known.     

Multicystic dysplastic kidney: Natural history of prenatally detected cases

To delineate the natural history of fetal multicystic dysplastic kidneys (MDKs), all cases that were prenatally detected in the Prenatal Diagnosis Center of the University of Virginia from September 1985 to 31 August 1988 were reviewed. All patients were followed through the Center with serial ultrasound evaluations at approximately 4-week intervals, and each liveborn infant was evaluated and followed by one of the authors (S.S.H.) Of the 14 cases detected, ten were detected in the second trimester, the earliest at 16·5 weeks' gestation. Of the nine fetuses with non-lethal disease, there were two cases in which the lesion remained unchanged during observation. Both had an initial diagnosis in the third trimester. In those cases diagnosed in the second trimester (7), all showed an initial increase in the size and number of cysts, followed by involutional changes either in utero (2) or in the neonatal period (3). Two infants had immediate surgical removal of the MDK, one because of respiratory compromise, and the other because of an uncertain diagnosis on renal scan. Abnormalities of the contralateral kidney were found in 7 of 14 fetuses. Five were lethal conditions. Associated non-renal abnormalities were common in bilateral MDK (80 per cent), but rare in unilateral MDK (11 per cent).     

Allelopathic potential of Medicago arborea, a Mediterranean invasive shrub

Summary. Biological invasions are nowadays a major problem in ecology. Allelopathy has been shown to be involved in such invasions, but this mechanism has been little studied in France. The objectives of this study were to evaluate the allelopathic potential of Medicago arborea, an invasive species in the French Mediterranean region. Foliar extracts were tested on three target species (Lactuca sativa, Lepidium sativum and Linum strictum). We showed that Medicago arborea has high allelopathic potential to affect the growth and germination of other species. Yellow flax (Linum strictum), native to the invaded area, was the most sensitive of the tested plant species to foliar extracts of Medicago arborea. Our study pointed out the role of allelopathy in processes leading to biological invasion, and more generally in population dynamics.     

Vision in the lanternfish Stenobrachius leucopsarus (Myctophidae)

The visual system of the midwater fish Stenobrachius leucopsarus (Myctophidae) has been studied by biochemical, anatomical, and electrophysiological methods. Partial bleaching analysis in the presence of hydroxylamine showed that the eye contains a single extractable photopigment, based on retinal and absorbing maximally at 492 nm. The photoreceptor population consists entirely of rods, approximately 5.0×10⁵ rods per mm² and 1.8×10⁷ per retina. Visual sensitivity is enhanced by the lack of pigment granules in the pigment epithelium and the presence of a choroidal tapetum lucidum. Influenced by the high concentration of visual pigment, the spectral sensitivity has a broad plateau between 460 and 540 nm, which suggests that the eye retains high sensitivity to a diversity of bioluminescent stimuli and depth-attenuated solar light.     

Production of DMSP and DMS during a mesocosm study of an Emiliania huxleyi bloom: influence of bacteria and Calanus finmarchicus grazing

We investigated the influence of bacteria and metazooplankton on the production of dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS) during blooms of Emiliania huxleyi (Lohmann) Hay and Mohler in seawater mesocosms. The phytoplankton succession was marked by the rapid collapse of an initial Skeletonema costatum (Greville) Cleve bloom followed by a small E. huxleyi bloom. The collapse of the diatom bloom was accompanied by an increase in concentrations of dissolved DMSP (DMSP_d) and bacterial abundance and activity (as determined by the thymidine incorporation technique). The increase in bacterial activity was followed by a rapid decrease in DMSP_d concentrations which remained low for the rest of the experiment, even during the subsequent collapse of the E. huxleyi blooms. The absence of DMSP_d and DMS peaks during the declining phase of the E. huxleyi blooms was attributed to the high bacterial activity prevailing at that time. The influence of metazooplankton grazing on DMSP and DMS production was investigated by adding moderate (24 mg dry weight m^-3) and high (520 mg dry weight m^-3) concentrations of Copepodite Stage V and adults of Calanus finmarchicus to two of four filtered (200 m mesh net) enclosures during the E. huxleyi blooms. The addition of C. finmarchicus, even in high concentrations, had no apparent effect on the dynamics of E. huxleyi, suggesting that the copepods were not grazing significantly on nanophytoplankton. The addition of copepods in high concentrations favored an accumulation of chlorophyll a and particulate DMSP. These results suggest that copepods were preying on the herbivorous microzooplankton which, in turn, was controlling the biomass of nanophytoplankton. DMS production was also enhanced in the enclosure with maximum metazooplankton biomass, suggesting that the grazing of C. finmarchicus on microzooplankton containing DMSP may contribute to DMS production. These results provide strong support to the emerging idea that bacteria and metazooplankton grazing play a dominant role in determining the timing and magnitude of DMS pulses following phytoplankton blooms.     

Modelling the dynamic air-water-sediment coupled fluxes and occurrence of polychlorinated biphenyls in a high altitude lake

The BIODEP model in terms of atmosphere-lake interactions was developed. The model was applied to an oligotrophic, dimictic high altitude lake (Lake Redo, Pyrenees) for a range of polychlorinated biphenyl (PCB) congeners. High altitude lakes, which receive their contaminant inputs uniquely from the atmosphere through long-range atmospheric transport, provide ideal controlled environments for the study of the interactions between atmospheric depositional and water column biogeochemical processes. The BIODEP model was able to predict dissolved water concentrations and PCB accumulation in the lake sediment within a factor of 2. This shows that the BIODEP model captures the essential processes driving the sink of POPs in high altitude lakes and that POP occurrence in the lake is driven by direct atmospheric inputs with limited influence from the watershed. An important seasonal variability in water column concentrations is predicted which should have important implications in sampling strategies. Furthermore, it is shown that diffusive air-water exchange dominated the PCB dynamics in the lake, especially for the less chlorinated biphenyls.     

Organochlorine compounds and stable isotopes indicate bottlenose dolphin subpopulation structure around the Iberian Peninsula

Isotopic signatures and organochlorine pollutant loads of organisms reflect the characteristics of the waters in which they live and feed. To investigate population structure of bottlenose dolphins around the Iberian Peninsula we determined delta(13)C and delta(15)N in the skin and organochlorine (OC) levels in the blubber of stranded bottlenose dolphins inhabiting the Mediterranean (Catalonia, Valencia and Balearic Islands) and adjacent Atlantic waters (Huelva and Portugal). OC levels were high in all regions, reflecting the predatory habits of the species, its coastal distribution and the existence of intense agricultural and industrial activity throughout the region. PCB congeners showed a gradient from the relatively more chlorinated forms to those that are less so, and followed a northeast to northwest direction across the Iberian Peninsula. This suggests that PCB inputs are more recent in the temperate latitudes of the eastern Atlantic Ocean than in the western Mediterranean Sea. Comparatively, OC ratios and isotopic signatures proved to be more efficient ways of discriminating groups than did raw OC concentrations. Significant differences in delta(13)C and in PCB congener profiles indicate that dolphins from the Atlantic and the Mediterranean do not intermingle. In addition, the two Atlantic groups differed in delta(15)N signature, tDDT concentration, DDT/PCB ratio and the PCB congener profile, which also suggests some degree of isolation between them. In the Mediterranean, dolphins from Catalonia and Valencia were indistinguishable, suggesting a common distribution area. However, dolphins from the Balearic Islands differed from those of the Peninsula in their DDT/PCB ratio and from all the other sample groups in their PCB congener profiles, which supports the hypothesis that the deep waters between the Islands and the Peninsula represent an effective barrier for the species.