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Response and potential of agroforestry crops under global change Full text
2010
Calfapietra, C. | Gielen, B. | Karnosky, D. | Ceulemans, R. | Scarascia Mugnozza, G.
The use of agroforestry crops is a promising tool for reducing atmospheric carbon dioxide concentration through fossil fuel substitution. In particular, plantations characterised by high yields such as short rotation forestry (SRF) are becoming popular worldwide for biomass production and their role acknowledged in the Kyoto Protocol. While their contribution to climate change mitigation is being investigated, the impact of climate change itself on growth and productivity of these plantations needs particular attention, since their management might need to be modified accordingly. Besides the benefits deriving from the establishment of millions of hectares of these plantations, there is a risk of increased release into the atmosphere of volatile organic compounds (VOC) emitted in large amounts by most of the species commonly used. These hydrocarbons are known to play a crucial role in tropospheric ozone formation. This might represent a negative feedback, especially in regions already characterized by elevated ozone level. Growth and management of agroforestry plantations will be influenced by climate change.
Show more [+] Less [-]A rapid bioassay for detecting saxitoxins using a Daphnia acute toxicity test Full text
2010
Ferrão-Filho, Aloysio Da S. | Soares, Maria Carolina S. | Magalhães, Valéria Freitas de | Azevedo, Sandra M.F.O.
Bioassays using Daphnia pulex and Moina micrura were designed to detect cyanobacterial neurotoxins in raw water samples. Phytoplankton and cyanotoxins from seston were analyzed during 15 months in a eutrophic reservoir. Effective time to immobilize 50% of the exposed individuals (ET50) was adopted as the endpoint. Paralysis of swimming movements was observed between ∼0.5-3 h of exposure to lake water containing toxic cyanobacteria, followed by an almost complete recovery of the swimming activity within 24 h after being placed in control water. The same effects were observed in bioassays with a saxitoxin-producer strain of Cylindrospermopsis raciborskii isolated from the reservoir. Regression analysis showed significant relationships between ET50vs. cell density, biomass and saxitoxins content, suggesting that the paralysis of Daphnia in lake water samples was caused by saxitoxins found in C. raciborskii. Daphnia bioassay was found to be a sensitive method for detecting fast-acting neurotoxins in natural samples, with important advantages over mouse bioassays.
Show more [+] Less [-]Eco-restoration: Simultaneous nutrient removal from soil and water in a complex residential–cropland area Full text
2010
Wu, Yonghong | Kerr, Philip G. | Hu, Zhengyi | Yang, Linzhang
An eco-restoration system to remove excess nutrients and restore the agricultural ecosystem balance was proposed and applied from August 2006 to August 2008 in a residential-cropland complex area (1.4 × 105 m2) in Kunming, western China, where the self-purifying capacity of the agricultural ecosystem had been lost. The proposed eco-restoration system examined includes three main foci: farming management, bioremediation, and wastewater treatment. The results showed that the removal efficiencies of total phosphorus (TP) and total nitrogen (TN) from the complex wastewater were 83% and 88%, respectively. The Simpson’s diversity indices of macrophytes and zoobenthos indicated that the system had increased macrophyte and zoobenthic diversity as well as improved growth conditions of the plankton habitats. The results demonstrated that the proposed eco-restoration system is a promising approach for decreasing the output of nutrients from soil, improving agricultural ecosystem health, and minimizing the downstream eutrophication risk for surface waters.
Show more [+] Less [-]Colloidal gold probe-based immunochromatographic assay for the rapid detection of lead ions in water samples Full text
2010
Tang, Yong | Zhai, Yi-Fan | Xiang, Jun-Jian | Wang, Hong | Liu, Bin | Guo, Chang-Wei
One-step immunochromatographic assay (ICA) has been developed using colloidal gold-labeled monoclonal antibody probe for the rapid detection of lead ions in water samples. The ICA was based on the theory of competitive reactivity, and the results can be easily judged based on the presence or absence of a red colored test line with visual detection. Under optimal conditions, this method shows high detecting sensitivity with a LOD (limit of detection) of 50 ng/ml. Stability test indicates that the immunochromatographic strips are stable for 8 weeks at room temperature. During practical application, nanometer TiO2 is used to enrich the lead ions in water samples. The ICA is successfully applied in the measurement of lead ion concentrations in local water samples, and the results are highly consistent with that of ICP-MS. Detecting lead ions with ICA can be done within 4 min and is very useful for the rapid onsite testing.
Show more [+] Less [-]The impact of ambient ozone on mountain spruce forests in the Czech Republic as indicated by malondialdehyde Full text
2010
Hůnová, Iva | Novotný, Radek | Uhlířová, Hana | Vráblík, Tomáš | Horálek, Jan | Lomský, Bohumír | Šrámek, Vít
Malondialdehyde (MDA), a product of lipid peroxidation and biomarker of oxidative stress, is measured over the long term in spruce Picea abies needles under real conditions in three Czech mountain border areas. The trends presented collate the MDA content in spruce needles with ambient ozone, temperature and precipitation as casual, and defoliation as a subsequent factor for the period 1994-2006. We have found the overall decreasing trends in MDA and defoliation. The highest MDA and defoliation are recorded in the Jizerske, the lowest in the Krusne hory Mts. Out of the examined variables the MDA is predicted best by mean temperature in vegetation season, median of O3 concentrations and AOT40; these three variables account for 34% of MDA1 and 36% of MDA2 variability. Our hypothesis that higher ambient O3 exposure results in higher MDA contents in P. abies needles under real conditions has not been approved.
Show more [+] Less [-]Ammonium and nitrate tolerance in lichens Full text
2010
Since lichens lack roots and take up water, solutes and gases over the entire thallus surface, these organisms respond more sensitively to changes in atmospheric purity than vascular plants. After centuries where effects of sulphur dioxide and acidity were in the focus of research on atmospheric chemistry and lichens, recently the globally increased levels of ammonia and nitrate increasingly affect lichen vegetation and gave rise to intense research on the tolerance of lichens to nitrogen pollution. The present paper discusses the main findings on the uptake of ammonia and nitrate in the lichen symbiosis and to the tolerance of lichens to eutrophication. Ammonia and nitrate are both efficiently taken up under ambient conditions. The tolerance to high nitrogen levels depends, among others, on the capability of the photobiont to provide sufficient amounts of carbon skeletons for ammonia assimilation. Lowly productive lichens are apparently predisposed to be sensitive to excess nitrogen.
Show more [+] Less [-]Anthropogenic input of polycyclic aromatic hydrocarbons into five lakes in Western China Full text
2010
The temporal distribution of polycyclic aromatic hydrocarbons (PAHs) was examined in dated sediments from five lakes in Western China. The surficial concentrations of seven carcinogenic PAHs (BaA, Chyr, BbF, BkF, BaP, DBA and INP, hereafter denoted as PAH7) were highly site-specific. The ΣPAH7 concentrations generally increased from the deep layers to surface sediments. The temporal trends of ΣPAH7 concentrations were clearly different from those reported in developed countries. From 1950s to 1980s, which PAHs started to decrease in developed countries, is the right period that PAHs started to increase rapidly in Western China. The fluxes and mass inventories suggest that the PAH7 input over the past three decades was much more rapidly than it was before the 1980s. Source identification indicates that the PAHs were primarily from biomass burning and domestic coal combustion, and increasing vehicular and/or industrial coal combustion emission was also found.
Show more [+] Less [-]Adaptation to osmotic stress provides protection against ammonium nitrate in Pelophylax perezi embryos Full text
2010
Adaptation to osmotic stress provides protection against ammonium nitrate in Pelophylax perezi embryos Full text
2010
The negative effects of pollution on amphibians are especially high when animals are additionally stressed by other environmental factors such as water salinity. However, the stress provoked by salinity may vary among populations because of adaptation processes. We tested the combined effect of a common fertilizer, ammonium nitrate (0–90.3 mg N–NO3NH4/L), and water salinity (0–2‰) on embryos of two Pelophylax perezi populations from ponds with different salinity concentrations. Embryos exposed to the fertilizer were up to 17% smaller than controls. Survival rates of embryos exposed to a single stressor were always below 10%. The exposure to both stressors concurrently increased mortality rate (>95%) of embryos from freshwater. Since the fertilizer was lethal only when individuals were stressed by the salinity, it did not cause lethal effects on embryos naturally adapted to saline environments. Our results underscore the importance of testing multiple stressors when analyzing amphibian sensitivity to environmental pollution. Natural resistance to salinity minimizes the impact of chemical fertilizers on amphibian embryos.
Show more [+] Less [-]Adaptation to osmotic stress provides protection against ammonium nitrate in Pelophylax perezi embryos Full text
2010
Ortiz-Santaliestra, Manuel E. | Fernández, M. José | Lizana, Miguel | Marco, Adolfo | Ministerio de Ciencia e Innovación (España) | Junta de Castilla y León
The negative effects of pollution on amphibians are especially high when animals are additionally stressed by other environmental factors such as water salinity. However, the stress provoked by salinity may vary among populations because of adaptation processes. We tested the combined effect of a common fertilizer, ammonium nitrate (0–90.3 mg N–NO3NH4/L), and water salinity (0–2‰) on embryos of two Pelophylax perezi populations from ponds with different salinity concentrations. Embryos exposed to the fertilizer were up to 17% smaller than controls. Survival rates of embryos exposed to a single stressor were always below 10%. The exposure to both stressors concurrently increased mortality rate (>95%) of embryos from freshwater. Since the fertilizer was lethal only when individuals were stressed by the salinity, it did not cause lethal effects on embryos naturally adapted to saline environments. Our results underscore the importance of testing multiple stressors when analyzing amphibian sensitivity to environmental pollution. | Funding was provided by the Regional Government of Castilla y León (SA071A06) and the Ministry of Science and Innovation of Spain (CGL2005-0372). | Peer reviewed
Show more [+] Less [-]Impact of dissolved organic matter on bioavailability of chlorotoluron to wheat Full text
2010
Chlorotoluron (Chl) is a phenylurea herbicide and is widely used for controlling weeds. While it has brought great benefits to crop production, it has also resulted in contamination to ecosystem. In this study, we investigated accumulation of chlorotoluron (Chl) and biological responses of wheat plants as affected by dissolved organic matter (DOM). Wheat seedlings grown under 10 mg kg−1 Chl for 4 d showed a low level of chlorophyll accumulation and damage to plasma membrane. The growth was inhibited by exposure of chlorotoluron. Treatment with 50 mg DOC kg−1 DOM derived either from sludge (DOM-SL) or straw (DOM-ST) attenuated the chlorotoluron toxicity to plants. Both DOMs decreased activities of catalase, peroxidase and superoxide dismutase in Chl-treated seedlings. However, an increased glutathione S-transferases activity was observed under the same condition. Wheat plants treated with Chl in the presence of DOM accumulated less Chl than those treated with Chl alone. Moreover, in the presence of DOM, bioconcentration factor (BCF) decreased whereas translocation factors increased. Analyses with FT-IR spectra confirmed the regulatory role of DOMs in reducing Chl accumulation in wheat. Dissolved organic matter (DOM) as a soil amendment can reduce herbicide accumulation in crops.
Show more [+] Less [-]Large-scale risk assessment of polycyclic aromatic hydrocarbons in shoreline sediments from Saudi Arabia: Environmental legacy after twelve years of the Gulf war oil spill Full text
2010
Bejarano, Adriana C. | Michel, Jacqueline
A large-scale assessment of polycyclic aromatic hydrocarbons (PAHs) from the 1991 Gulf War oil spill was performed for 2002-2003 sediment samples (n = 1679) collected from habitats along the shoreline of Saudi Arabia. Benthic sediment toxicity was characterized using the Equilibrium Partitioning Sediment Benchmark Toxic Unit approach for 43 PAHs (ESBTUFCV,43). Samples were assigned to risk categories according to ESBTUFCV,43 values: no-risk (≤1), low (>1–≤2), low-medium (>2–≤3), medium (>3–≤5) and high-risk (>5). Sixty seven percent of samples had ESBTUFCV,43 > 1 indicating potential adverse ecological effects. Sediments from the 0–30 cm layer from tidal flats, and the >30–<60 cm layer from heavily oiled halophytes and mangroves had high frequency of high-risk samples. No-risk samples were characterized by chrysene enrichment and depletion of lighter molecular weight PAHs, while high-risk samples showed little oil weathering and PAH patterns similar to 1993 samples. North of Safaniya sediments were not likely to pose adverse ecological effects contrary to sediments south of Tanaqib. Landscape and geomorphology has played a role on the distribution and persistence in sediments of oil from the Gulf War.
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