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111.
Starting from six regional climate change scenarios, nitrogen leaching from arable-soil, water discharge, and nitrogen retention was modeled in the R?nne? catchment. Additionally, biological response was modeled in the eutrophic Lake Ringsj?n. The results are compared with similar studies on other catchments. All scenarios gave similar impact on water quality but varied in quantities. However, one scenario resulted in a different transport pattern due to less-pronounced seasonal variations in the hydrology. On average, the study shows that, in a future climate, we might expect: i) increased concentrations of nitrogen in the arable root zone (+50%) and in the river (+13%); ii) increased annual load of nitrogen from land to sea (+22%) due to more pronounced winter high flow; moreover, remote areas in the catchment may start to contribute to the outlet load; iii) radical changes in lake biochemistry with increased concentrations of total phosphorus (+50%), total nitrogen (+20%), and planktonic algae such as cyanobacteria (+80%). 相似文献
112.
Ertunç T Schmidt B Kühn H Bertmer M Schäffer A 《Journal of environmental science and health. Part. B》2004,39(5-6):689-707
13C-labelled cyprodinil was applied on 13C-depleted wheat plants with 27-fold field application rate. A control experiment applying same amounts of 14C-cyprodinil showed that main portions of the residues were detected in the cellulose (15% NER), hemicellulose (28.3% NER), and lignin fraction (23.3% NER). 16.7% were detected in water soluble polymers, 6% in both, pectin and protein fraction, and 4% in the starch containing fraction. Free cyprodinil was detectable by TLC in all fractions except lignin. A direct characterization of the residues in vivo by CP-MAS was not successful. Cell wall fractions were further analysed by liquid state NMR to determine the structure of the mobilized highly polymer/polar residues: Within lignin, where most of the residues were located at field application rate, neither intact cyprodinil nor its metabolites could not be detected. The 13C-label introduced was probably incorporated in the polymer as natural lignin monomers and thus are not considered as bound residues according to IUPAC definition. 相似文献
113.
Summary In many altricial species including the great tit (Parus major) the intensity of brood defense against predators has been shown to increase with the age of the offspring. This effect has been ascribed amongst others to the young becoming more vulnerable as they age (vulnerability hypothesis). In a great tit population suffering heavy losses from brood depredation by the great spotted woodpecker (Dendrocopus major), we rendered first and second broods more vulnerable by artificially enlarging the entrance of the nest hole. Contrary to the vulnerability hypothesis, 16 experimental pairs defended their brood against a dummy great spotted woodpecker less vigorously than did 16 control pairs. Nest concealment behavior potentially compromising active defense was minimized by simultaneous playback of nestling distress calls, thus simulating the act of nest predation. This leaves the brood value hypothesis as an alternative functional explanation of the defense level — age effect. It predicts that parents should defend their brood in proportion to the reproductive value (or some more suitable cohortal equivalent measure) of their offspring. At present, this explanation pertains to one predator species. In first broods, but not in second broods, males defended them more vigorously than did their females. While this parallels previous experiments on brood defense against predators posing a much greater risk to the parents, two functional explanations previously put forward can hardly apply. 相似文献
114.
115.
Michaelowa Axel Schmidt Holger 《Mitigation and Adaptation Strategies for Global Change》1997,2(1):45-56
Joint Implementation is a theoretically efficient instrument of climate policy at least in the short run. This need not apply
for the long run. Joint Implementation can reduce innovation in the industrialized countries because of reduced incentives
for emission reduction. To realize short run efficiency gains and to avoid long run efficiency losses, we need a ‘strategic’
climate policy. This policy should start with full crediting of Joint Implementation allowing short-run efficiency gains which
can foster technology transfer and thus lead to ‘leapfrogging’ by developing countries. Over time, the crediting ratio should
be gradually reduced while domestic carbon taxes are raised. Experiences from the second oil shock have shown that energy-saving
innovation is positively correlated to energy prices. Both, the reduced crediting and the raising domestic carbon tax, will
therefore lead to long-run innovation. 相似文献
116.
117.
118.
Trace element concentration in wheat grain: results from the Swedish long-term soil fertility experiments and national monitoring program 总被引:4,自引:1,他引:3
Holger Kirchmann Lennart Mattsson Jan Eriksson 《Environmental geochemistry and health》2009,31(5):561-571
Concentrations of trace elements in wheat grain sampled between 1967 and 2003 from the Swedish long-term soil fertility experiments
were analyzed using ICP-MS. The long-term effect of inorganic and organic fertilization on trace metal concentrations was
investigated including the impact of atmospheric deposition and myccorhiza, whereas other factors such as soil conditions,
crop cultivar, etc. are not discussed in this paper. Mean values derived from 10 experimental sites were reported. Significantly
declining Pb and Cd concentrations in wheat grain could be explained by lower atmospheric deposition. Mean Se contents in
all samples were 0.031 mg kg−1 grain dry weight. No samples had sufficiently high Se concentrations for human (0.05 mg Se kg−1) or animal demand (0.1 mg Se kg−1). Concentrations of Co in wheat grain were extremely low, 0.002–0.005 mg Co kg−1 grain dry weight, and far below the minimum levels required by animals, which applied to all fertilizer treatments. A doubling
of Mo concentrations in grain since 1975 resulted in Cu/Mo ratios often below one, which may cause molybdenosis in ruminants.
The increase in Mo concentrations in crops correlated with the decline in sulfur deposition. Concentrations of Cu and Fe declined
in NPK-fertilized wheat as compared to unfertilized or manure-treated wheat. Very low concentrations of Se and Co and low
concentrations of Fe and Cu require attention to counteract risks for deficiencies. The main characteristic of the study is
that there are few significant changes over time between different fertilizer treatments, but throughout there are low concentrations
of most trace elements in all treatments. In general, good agreement between concentrations in wheat from the long-term fertility
experiments and the national monitoring program indicate that values are representative. 相似文献
119.
Stable isotope (SI) ratios of carbon (δ13C) and nitrogen (δ15N) were measured in omnivorous and carnivorous deep-sea copepods of the families Euchaetidae and Aetideidae across the Atlantic
sector of the Southern Ocean to establish their trophic positions. Due to high and variable C/N ratios related to differences
in lipid content, δ13C was corrected using a lipid-normalisation model. δ15N signals ranged from 3.0–6.9‰ in mesopelagic species to 7.0–9.5‰ in bathypelagic congeners. Among the carnivorous Paraeuchaeta species, the epi- to mesopelagic species Paraeuchaeta
antarctica had lower δ15N values than the mesopelagic P. rasa and bathypelagic P. barbata. The same trend was observed among omnivorous Aetideidae, but was not significant. In the most abundant species P. antarctica, individuals from the western Atlantic had higher δ13C and δ15N values than specimens at the eastern stations. These longitudinal changes in δ13C and δ15N values were attributed to regional differences in hydrography and sea surface temperature (SST), in particular related to
a northward extension of the Antarctic Polar Front (APF) at the easternmost stations. The results indicate that even in a
mesopelagic carnivorous species, the changes in surface stable isotope signatures are pronounced. 相似文献
120.
A comparison of predicted and measured levels of runoff-related pesticide concentrations in small lowland streams on a landscape level 总被引:1,自引:0,他引:1
Short-term pollution events via runoff are typical of streams in agricultural areas. Existing runoff models that simulate pesticide loss from agricultural fields require extensive input of information. There is thus a need for a simple model that can predict runoff-related pesticide concentrations in many streams on a landscape level when only limited data are available. To validate such a model, the runoff-related pesticide load of 18 small lowland streams was predicted with an extended version of the model "simplified formula for indirect loadings caused by runoff" (available from the Organisation for Economic Cooperation and Development, OECD). The authors suggest that the model presented here is suitable for use in routine exposure assessment of pesticides on a landscape level, as all input data (soil, slope, precipitation, pesticide application) are readily available from public authorities or could be generated by simple regional flood hydrograph curves. The predicted concentrations were compared with measured concentrations obtained by runoff-triggered sampling. Fungicides, insecticides and herbicides were detected in 17 streams, with max. concentrations measuring up to 29.7 microg/l for the fungicide azoxystrobin and 0.3 microg/l for the insecticide parathion-ethyl. Herbicides were detected in 16 streams, with max. concentrations between 13.7 and 1.2 microg/l. The linear regression between the predicted and measured concentrations (log-values) shows significant correlations for the following pesticides: azoxystrobin: r2=0.43; p=0.03; epoxiconazole: r2=0.71; por=0.5 microg/l). 相似文献