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Withered on the stem: is bamboo a seasonally limiting resource for giant pandas? Полный текст
2017
Li, Youxu | Swaisgood, Ronald R. | Wei, Wei | Nie, Yonggang | Hu, Yibo | Yang, Xuyu | Gu, Xiaodong | Zhang, Zejun
In response to seasonal variation in quality and quantity of available plant biomass, herbivorous foragers may alternate among different plant resources to meet nutritional requirements. Giant pandas (Ailuropoda melanoleuca) are reliant almost exclusively on bamboo which appears omnipresent in most occupied habitat, but subtle temporal variation in bamboo quality may still govern foraging strategies, with population-level effects. In this paper, we investigated the possibility that temporal variation in the quality of this resource is involved in population regulation and examined pandas’ adaptive foraging strategies in response to temporal variation in bamboo quality. Giant pandas in late winter and early spring consumed a less optimal diet in Foping Nature Reserve, as the availability of the most nutritious and preferred components and age classes of Bashania fargesii declined, suggesting that bamboo may be a seasonally limiting resource. Most panda mortalities and rescues occurred during the same period of seasonal food limitation. Our findings raised the possibility that while total bamboo biomass may not be a limiting factor, carrying capacity may be influenced by subtle seasonal variation in bamboo quality. We recommend that managers and policy-makers should consider more than just the quantity of bamboo in the understory and that carrying capacity estimates should be revised downward to reflect the fact that all bamboos are not equal.
Показать больше [+] Меньше [-]Amelioration of boron toxicity in sweet pepper as affected by calcium management under an elevated CO2 concentration Полный текст
2017
Piñero, María Carmen | Pérez-Jiménez, Margarita | López-Marín, Josefa | del Amor, Francisco M.
We investigated B tolerance in sweet pepper plants (Capsicum annuun L.) under an elevated CO₂ concentration, combined with the application of calcium as a nutrient management amelioration technique. The data show that high B affected the roots more than the aerial parts, since there was an increase in the shoot/root ratio, when plants were grown with high B levels; however, the impact was lessened when the plants were grown at elevated CO₂, since the root FW reduction caused by excess B was less marked at the high CO₂ concentration (30.9% less). Additionally, the high B concentration affected the membrane permeability of roots, which increased from 39 to 54% at ambient CO₂ concentration, and from 38 to 51% at elevated CO₂ concentration, producing a cation imbalance in plants, which was differentially affected by the CO₂ supply. The Ca surplus in the nutrient solution reduced the nutritional imbalance in sweet pepper plants produced by the high B concentration, at both CO₂ concentrations. The medium B concentration treatment (toxic according to the literature) did not result in any toxic effect. Hence, there is a need to review the literature on critical and toxic B levels taking into account increases in atmospheric CO₂.
Показать больше [+] Меньше [-]The biological responses and metal phytoaccumulation of duckweed Spirodela polyrhiza to manganese and chromium Полный текст
2017
Liu, Ying | Sanguanphun, Tanatcha | Yuan, Wenqiao | Cheng, Jay J. | Meetam, Metha
The phytoaccumulation ability of duckweed Spirodela polyrhiza on manganese (Mn) and chromium (Cr) was assessed by exposing the plant to various concentrations of single or dual metals (5–70 mg L⁻¹ Mn, 2–12 mg L⁻¹ Cr(VI)) under laboratory conditions. The results showed that S. polyrhiza can tolerate Mn at high concentrations of up to 70 mg L⁻¹, and its growth rate was barely affected by Mn. The effects of Cr on S. polyrhiza growth were dose-dependent, and the growth was completely inhibited in the presence of 12 mg L⁻¹ Cr. Analysis of metal content in the plant biomass revealed a high accumulation of Mn (up to 15.75 mg per g of duckweed dry weight). The Cr bioaccumulation (from below detection limit to 2.85 mg Cr (11.84 mg Cr₂O₇ ²⁻) per g of duckweed dry weight) increased with cultivation time and metal concentration in the medium. Further study with the concurrence of Mn and Cr showed increased toxicity to plant growth and photosynthesis. The metal accumulations in the dual metal treatments were also significantly decreased as compared to the single metal treatments. Nevertheless, the phytoaccumulation of these two metals in S. polyrhiza in the dual metal treatments were still comparable to or higher than in previous reports. Thus, it was concluded that duckweed S. polyrhiza has the potential to be used as a phytoremediator in aquatic environments for Mn and Cr removal.
Показать больше [+] Меньше [-]Assessment of Pb and pyrene accumulation in Scirpus triqueter assisted by combined alkyl polyglucoside and nitrilotriacetic acid application Полный текст
2017
Chen, Tingru | Liu, Xiaoyan | Zhang, Xinying | Hu, Xiaoxin | Cao, Liya
To understand the accumulation and uptake of polycyclic aromatic hydrocarbons (PAHs) and heavy metals by plants is an important part of the assessment of phytoremediation for PAHs and heavy metals co-contaminated soil. This study was an investigation of the accumulation and uptake of pyrene and lead (Pb) by Scirpus triqueter under the condition of alkyl polyglucoside (APG) and nitrilotriacetic acid (NTA) combined application. The results indicated that the accumulation of Pb by S. triqueter was significantly improved by NTA and APG addition into the soil. The pyrene accumulation in plant was also increased after application of APG when compared to the control treatment. However, the pyrene accumulation was decreased when APG was applied together with NTA. SEM and TEM images of root surface suggested that more Pb in the soil transferred to the plant by combined application of APG and NTA. More importantly, TEM images of xylem cells of S.triqueter root showed that permeability of cell membrane was improved by application of APG.
Показать больше [+] Меньше [-]Simultaneous effect of dissolved organic carbon, surfactant, and organic acid on the desorption of pesticides investigated by response surface methodology Полный текст
2017
Trinh, Ha Thu | Duong, Hanh Thi | Ta, Thao Thi | Van Cao, Hoang | Strobel, Bjarne W. | Le, Giang Truong
Desorption of pesticides (fenobucarb, endosulfan, and dichlorodiphenyltrichloroethane (DDT)) from soil to aqueous solution with the simultaneous presence of dissolved organic carbon (DOC), sodium dodecyl sulfate (SDS), and sodium oxalate (Oxa) was investigated in batch test by applying a full factorial design and the Box–Behnken response surface methodology (RSM). Five concentration levels of DOC (8 to 92 mg L⁻¹), SDS (0 to 6.4 critical micelle concentration (CMC)), and Oxa (0 to 0.15 M) were used for the experiments with a rice field topsoil. The results of RSM analysis and analysis of variance (ANOVA) have shown that the experimental data could be well described by quadratic regression equations with determination coefficients (R ²) of 0.990, 0.976, and 0.984 for desorption of fenobucarb, endosulfan, and DDT, respectively. The individual effects and interaction of DOC, SDS, and Oxa were evaluated through quadratic regression equations. When the aqueous solution includes 50 mg L⁻¹ DOC, 3.75 CMC SDS, and 0.1 M Oxa, the maximum desorption concentrations of fenobucarb, endosulfan, and DDT were 96, 80, and 75 μg L⁻¹, respectively. The lowest concentration of SDS, DOC, and Oxa caused the minimum desorption. This point at conditions of concern for flooding water is high content of organic compounds causing potentially high contamination by desorption, and the remarkably lower desorption at organic matter-free conditions. The suspended organic matter is one of the common characteristics of flooding and irrigation water in rice fields, and surfactants from pollution increase the problem with desorption of legacy pesticides in the rice fields.
Показать больше [+] Меньше [-]A comprehensive review on removal of arsenic using activated carbon prepared from easily available waste materials Полный текст
2017
Mondal, Monoj Kumar | Garg, Ravi
Arsenic contamination in water bodies is a serious problem and causes various health problems due to which US Environment Protection Agency (USEPA) set its maximum permissible limit of 10 ppb. The present review article starts with the removal of toxic arsenic using adsorbents prepared from easily available waste materials. Adsorbent either commercial or low-cost adsorbent can be used for arsenic removal but recent research was focused on the low-cost adsorbent. Preparation and activation of various adsorbents were discussed. Adsorption capacities, surface area, thermodynamic, and kinetics data of various adsorbents for As(III) and As(V) removal were compiled. Desorption followed by regeneration and reuse of adsorbents is an important step in adsorption and leads to economical process. Various desorbing and regenerating agents were discussed for arsenic decontamination from the adsorbent surface. Strong acids, bases, and salts are the main desorbing agents. Disposal of arsenic-contaminated adsorbent and arsenic waste was also a big problem because of the toxic and leaching effect of arsenic. So, arsenic waste was disposed of by proper stabilization/solidification (S/S) technique by mixing it in Portland cement, iron, ash, etc. to reduce the leaching effect.
Показать больше [+] Меньше [-]Empirical research on coordination evaluation and sustainable development mechanism of regional logistics and new-type urbanization: a panel data analysis from 2000 to 2015 for Liaoning Province in China Полный текст
2017
Sun, Qiang
As the largest developing country in the world, China has witnessed fast-paced urbanization over the past three decades with rapid economic growth. In fact, urbanization has been not only shown to promote economic growth and improve the livelihood of people but also can increase demands of regional logistics. Therefore, a better understanding of the relationship between urbanization and regional logistics is important for China’s future sustainable development. The development of urban residential area and heterogeneous, modern society as well regional logistics are running two abreast. The regional logistics can promote the development of new-type urbanization jointly by promoting industrial concentration and logistics demand, enhancing the residents’ quality of life and improving the infrastructure and logistics technology. In this paper, the index system and evaluation model for evaluating the development of regional logistics and the new-type urbanization are constructed. Further, the econometric analysis is utilized such as correlation analysis, co-integration test, and error correction model to explore relationships of the new-type urbanization development and regional logistics development in Liaoning Province. The results showed that there was a long-term stable equilibrium relationship between the new-type urbanization and regional logistics. The findings have important implications for Chinese policymakers that on the path towards a sustainable urbanization and regional reverse, this must be taken into consideration. The paper concludes providing some strategies that might be helpful to the policymakers in formulating development policies for sustainable urbanization.
Показать больше [+] Меньше [-]Evidence for contrasting accumulation pattern of cadmium in relation to other elements in Senilia senilis and Tagelus adansoni from the Bijagós archipelago, Guinea-Bissau Полный текст
2017
Catry, Teresa | Figueira, Paula | Carvalho, Lina | Monteiro, Rui | Coelho, Pedro | Lourenço, Pedro Miguel | Catry, Paulo | Tchantchalam, Quintino | Catry, Inês | Botelho, Maria J. | Pereira, Eduarda | Granadeiro, José Pedro | Vale, Carlos
Evidence for contrasting accumulation pattern of cadmium in relation to other elements in Senilia senilis and Tagelus adansoni from the Bijagós archipelago, Guinea-Bissau Полный текст
2017
Catry, Teresa | Figueira, Paula | Carvalho, Lina | Monteiro, Rui | Coelho, Pedro | Lourenço, Pedro Miguel | Catry, Paulo | Tchantchalam, Quintino | Catry, Inês | Botelho, Maria J. | Pereira, Eduarda | Granadeiro, José Pedro | Vale, Carlos
Shellfish harvesting in intertidal areas is a widespread and economically important activity in many countries across West Africa. However, in some areas, there is virtually no information concerning the levels of contaminants (and other elements related to nutritional aspects) in the harvested species. We collected sediments and several individuals of the West African bloody cockle Senilia senilis and of the razor clam Tagelus adansoni during the dry season of 2015 nearby three islands in the Bijagós archipelago, Guinea-Bissau. Aluminium, Ca, Fe, Mg, As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn were determined in sediments and whole soft tissues of the two bivalves. Sediments showed uniformly low trace element concentrations, pointing to an ecosystem with low levels of trace element contamination. T. adansoni presented higher concentrations of most elements than S. senilis, with the exception of Cd that showed up to 40 times higher values in S. senilis than in T. adansoni from the same sites. Furthermore, Cd concentrations (25±8.7 mg kg⁻¹, dw) in S. senilis are clearly above the maximum level established for human consumption. Future studies should clarify whether biological factors are the major responsible for this unusual situation.
Показать больше [+] Меньше [-]Evidence for contrasting accumulation pattern of cadmium in relation to other elements in Senilia senilis and Tagelus adansoni from the Bijagós archipelago, Guinea-Bissau Полный текст
2017
Catry, Teresa | Figueira, Paula | Carvalho, Lina | Monteiro, Rui J. R. | Coelho, Pedro Duarte | Lourenço, Pedro Miguel | Catry, Paulo | Tchantchalam, Quintino | Catry, Inês | Botelho, Maria J. | Pereira, Eduarda | Granadeiro, José Pedro | Vale, Carlos
Shellfish harvesting in intertidal areas is a widespread and economically important activity in many countries across West Africa. However, in some areas, there is virtually no information concerning the levels of contaminants (and other elements related to nutritional aspects) in the harvested species. We collected sediments and several individuals of the West African bloody cockle Senilia senilis and of the razor clam Tagelus adansoni during the dry season of 2015 nearby three islands in the Bijagós archipelago, Guinea-Bissau. Aluminium, Ca, Fe, Mg, As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn were determined in sediments and whole soft tissues of the two bivalves. Sediments showed uniformly low trace element concentrations, pointing to an ecosystem with low levels of trace element contamination. T. adansoni presented higher concentrations of most elements than S. senilis, with the exception of Cd that showed up to 40 times higher values in S. senilis than in T. adansoni from the same sites. Furthermore, Cd concentrations (25±8.7 mg kg(-1), dw) in S. senilis are clearly above the maximum level established for human consumption. Future studies should clarify whether biological factors are the major responsible for this unusual situation. | Fundação para a Ciência e a Tecnologia (FCT); MAVA Foundation; | info:eu-repo/semantics/publishedVersion
Показать больше [+] Меньше [-]Changes of erythrocyte-metric parameters in Pelophylax ridibundus (Amphibia: Anura: Ranidae) inhabiting water bodies with different types of anthropogenic pollution in Southern Bulgaria Полный текст
2017
The article presents the basic erythrocyte-metric parameters: cell length (EL) and width (EW), EL/EW, erythrocyte size (ES), nucleus length (NL) and width (NW), NL/NW, nucleus size (NS) and nucleocytoplasmic ratio (NS/ES) in the wild populations of marsh frogs Pelophylax ridibundus from five water bodies in Southern Bulgaria (two rivers and three reservoirs) with different degrees and types of anthropogenic pollution (less disrupted water basins, domestic sewage pollution and heavy metal pollution). The changes in erythrocyte-metric parameters depend on concentrations and types of toxicant and, to a lesser extent, on the type of water basin. We found that when P. ridibundus populations live in conditions of domestic sewage pollution, EL, EW and ES increase in comparison with the control samples, with regard to an elongated elliptical cell shape. Simultaneously, NL, NW and NS did not undergo any significant changes when compared with the control samples. The nuclei had elliptical shape. In the populations from the water basins with heavy metal pollution, EL, EW, ES, NL, NW and NS decreased. The cells and nuclei had a circular shape. NS/ES decreased when compared with the control sample, regardless of the type of toxicants.
Показать больше [+] Меньше [-]A comparison between two full-scale MBR and CAS municipal wastewater treatment plants: techno-economic-environmental assessment Полный текст
2017
A holistic assessment procedure has been used in this study for comparing conventional activated sludge (CAS) and membrane bioreactor (MBR) processes for the treatment of municipal wastewater. Technical, social, administrative, economic and environmental impacts have been evaluated based on 1 year of operational data from three full-scale lines (one MBR and two CAS) working in parallel in a large municipal treatment plant. The comparative assessment evidences a slight advantage of the conventional process in the studied case, essentially due to lower costs, complexity and energy consumption. On the other hand, the MBR technology has a better social acceptance and similar overall environmental footprint. Although these results are influenced by site-specific parameters and cannot be generalized, the assessment procedure allowed identifying the most important factors affecting the final scores for each technology and the main differences between the compared technologies. Local conditions can affect the relative importance of the assessed impacts, and the use of weighting factors is proposed for better tailoring the comparative assessment to the local needs and circumstances. A sensitivity analysis on the weighted final scores demonstrated how local factors are very important and must be carefully evaluated in the decision making process.
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