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Tracing decadal environmental change in ombrotrophic bogs using diatoms from herbarium collections and transfer functions
2013
Poulíčková, Aloisie | Hájková, Petra | Kintrová, Kateřina | Bat'ková, Romana | Czudková, Markéta | Hájek, Michal
Central European mountain bogs, among the most valuable and threatened of habitats, were exposed to intensive human impact during the 20th century. We reconstructed the subrecent water chemistry and water-table depths using diatom based transfer functions calibrated from modern sampling. Herbarium Sphagnum specimens collected during the period 1918–1998 were used as a source of historic diatom samples. We classified samples into hummocks and hollows according to the identity of dominant Sphagnum species, to reduce bias caused by uneven sampling of particular microhabitats. Our results provide clear evidence for bog pollution by grazing during the period 1918–1947 and by undocumented aerial liming in the early 90-ies. We advocate use of herbarized epibryon as a source of information on subrecent conditions in recently polluted mires.
Afficher plus [+] Moins [-]Urban metabolism: A review of research methodologies
2013
Zhang, Yan
Urban metabolism analysis has become an important tool for the study of urban ecosystems. The problems of large metabolic throughput, low metabolic efficiency, and disordered metabolic processes are a major cause of unhealthy urban systems. In this paper, I summarize the international research on urban metabolism, and describe the progress that has been made in terms of research methodologies. I also review the methods used in accounting for and evaluating material and energy flows in urban metabolic processes, simulation of these flows using a network model, and practical applications of these methods. Based on this review of the literature, I propose directions for future research, and particularly the need to study the urban carbon metabolism because of the modern context of global climate change. Moreover, I recommend more research on the optimal regulation of urban metabolic systems.
Afficher plus [+] Moins [-]Salinisation of rivers: An urgent ecological issue
2013
Cañedo-Argüelles, Miguel | Kefford, Ben J. | Piscart, Christophe | Prat i Fornells, Narcís | Schäfer, Ralf B. | Schulz, Claus-Jürgen
Secondary salinisation of rivers and streams is a global and growing threat that might be amplified by climate change. It can have many different causes, like irrigation, mining activity or the use of salts as de-icing agents for roads. Freshwater organisms only tolerate certain ranges of water salinity. Therefore secondary salinisation has an impact at the individual, population, community and ecosystem levels, which ultimately leads to a reduction in aquatic biodiversity and compromises the goods and services that rivers and streams provide. Management of secondary salinization should be directed towards integrated catchment strategies (e.g. benefiting from the dilution capacity of the rivers) and identifying threshold salt concentrations to preserve the ecosystem integrity. Future research on the interaction of salinity with other stressors and the impact of salinization on trophic interactions and ecosystem properties is needed and the implications of this issue for human society need to be seriously considered.
Afficher plus [+] Moins [-]Carbon storage and sequestration by trees in urban and community areas of the United States
2013
Nowak, David J. | Greenfield, Eric J. | Hoehn, Robert E. | Lapoint, Elizabeth
Carbon storage and sequestration by urban trees in the United States was quantified to assess the magnitude and role of urban forests in relation to climate change. Urban tree field data from 28 cities and 6 states were used to determine the average carbon density per unit of tree cover. These data were applied to statewide urban tree cover measurements to determine total urban forest carbon storage and annual sequestration by state and nationally. Urban whole tree carbon storage densities average 7.69 kg C m−2 of tree cover and sequestration densities average 0.28 kg C m−2 of tree cover per year. Total tree carbon storage in U.S. urban areas (c. 2005) is estimated at 643 million tonnes ($50.5 billion value; 95% CI = 597 million and 690 million tonnes) and annual sequestration is estimated at 25.6 million tonnes ($2.0 billion value; 95% CI = 23.7 million to 27.4 million tonnes).
Afficher plus [+] Moins [-]Assessment of potential climate change impacts on peatland dissolved organic carbon release and drinking water treatment from laboratory experiments
2013
Tang, R. | Clark, J.M. | Bond, T. | Graham, N. | Hughes, D. | Freeman, C.
Catchments draining peat soils provide the majority of drinking water in the UK. Over the past decades, concentrations of dissolved organic carbon (DOC) have increased in surface waters. Residual DOC can cause harmful carcinogenic disinfection by-products to form during water treatment processes. Increased frequency and severity of droughts combined with and increased temperatures expected as the climate changes, have potentials to change water quality. We used a novel approach to investigate links between climate change, DOC release and subsequent effects on drinking water treatment. We designed a climate manipulation experiment to simulate projected climate changes and monitored releases from peat soil and litter, then simulated coagulation used in water treatment. We showed that the ‘drought’ simulation was the dominant factor altering DOC release and affected the ability to remove DOC. Our results imply that future short-term drought events could have a greater impact than increased temperature on DOC treatability.
Afficher plus [+] Moins [-]Ozone distribution in remote ecologically vulnerable terrain of the southern Sierra Nevada, CA
2013
Panek, Jeanne | Saah, David | Esperanza, Annie | Bytnerowicz, Andrzej | Fraczek, Witold | Cisneros, Ricardo
Ozone concentration spatial patterns remain largely uncharacterized across the extensive wilderness areas of the Sierra Nevada, CA, despite being downwind of major pollution sources. These natural areas, including four national parks and four national forests, contain forest species that are susceptible to ozone injury. Forests stressed by ozone are also more vulnerable to other agents of mortality, including insects, pathogens, climate change, and ultimately fire. Here we analyze three years of passive ozone monitor data from the southern Sierra Nevada and interpolate landscape-scale spatial and temporal patterns during the summer-through-fall high ozone concentration period. Segmentation analysis revealed three types of ozone exposure sub-regions: high, low, and variable. Consistently high ozone exposure regions are expected to be most vulnerable to forest mortality. One high exposure sub-region has been documented elsewhere as being further vulnerable to increased drought and fire potential. Identifying such hot-spots of forest vulnerability has utility for prioritizing management.
Afficher plus [+] Moins [-]Global climate change: Impact of diurnal temperature range on mortality in Guangzhou, China
2013
Yang, Jun | Liu, Hua-Zhang | Ou, Chun-Quan | Lin, Guo-Zhen | Zhou, Qin | Shen, Gi-Chuan | Chen, Ping-Yan | Guo, Yuming
Diurnal temperature range (DTR) is an important meteorological indicator associated with global climate change, but little is known about the effects of DTR on mortality. We examined the effects of DTR on cause-/age-/education-specific mortality in Guangzhou, a subtropical city in China during 2003–2010. A quasi-Poisson regression model combined with distributed lag non-linear model was used to examine the effects of DTR, after controlling for daily mean temperature, air pollutants, season and day of the week. A 1 °C increase in DTR at lag 0–4 days was associated with a 0.47% (95% confidence interval: 0.01%–0.93%) increase in non-accidental mortality. Stroke mortality was most sensitive to DTR. Female, the elderly and those with low education were more susceptible to DTR than male, the youth and those with high education, respectively. Our findings suggest that vulnerable subpopulations should pay more attention to protect themselves from unstable daily weather.
Afficher plus [+] Moins [-]Estimation of main greenhouse gases emission from household energy consumption in the West Bank, Palestine
2013
Abu-Madi, Maher | Rayyan, Ma'moun Abu
The main GHGs (CO2, NOx, and SO2) have been quantified based on national energy and population statistics. The results show that the contribution of households' energy consumption in the West Bank to global CO2 emission is about 0.016%, while contribution of total energy consumption by all sectors is about 0.041%. The results show that wood is the most polluting energy source in terms of CO2 and NOx emission, while electricity is the most polluting source in terms of SO2. Other sources like diesel, kerosene, and LPG that contribute to the GHGs emission are also quantified. The total amounts of CO2, NOx, and SO2 by households in the West Bank are 4.7 million tonne per year, 3.02 thousand tonne per year, and 2.23 thousand tonne per year respectively. This study presents a set of measures that might help in reducing the level of GHGs emission and protect the environment.
Afficher plus [+] Moins [-]Life stage-specific effects of the fungicide pyrimethanil and temperature on the snail Physella acuta (Draparnaud, 1805) disclose the pitfalls for the aquatic risk assessment under global climate change
2013
Seeland, Anne | Albrand, Jennifer | Oehlmann, Jörg | Müller, Ruth
It can be suggested that the combined stress of pesticide pollution and suboptimal temperature influences the sensitivity of life stages of aquatic invertebrates differently.The embryo, juvenile, half- and full-life-cycle toxicity tests performed with the snail Physella acuta at different concentrations (0.06–0.5 or 1.0 mg L−1) of the model fungicide pyrimethanil at 15, 20 and 25 °C revealed, that pyrimethanil caused concentration-dependent effects at all test temperatures. Interestingly, the ecotoxicity of pyrimethanil was higher at lower (suboptimal) temperature for embryo hatching and F1 reproduction, but its ecotoxicity for juvenile growth and F0 reproduction increased with increasing temperature.The life-stage specific temperature-dependent ecotoxicity of pyrimethanil and the high fungicide susceptibility of the invasive snail clearly demonstrate the complexity of pesticide–temperature interactions and the challenge to draw conclusions for the risk of pesticides under the impact of global climate change.
Afficher plus [+] Moins [-]Maternal effects of inducible tolerance against the toxic cyanobacterium Microcystis aeruginosa in the grazer Daphnia carinata
2013
Jiang, Xiaodong | Yang, Wei | Zhao, Shiye | Liang, Huishuang | Zhao, Yunlong | Chen, Liqiao | Li, Rui
Cyanobacterial blooms are becoming potent agents of natural selection in aquatic ecosystems because of their high production of some toxins and increased frequency in recent decades with eutrophication and climate change. Maternal exposure to the toxic Microcystis aeruginosa significantly increased the intrinsic rates of population increase, average life span, and net reproductive rates of a clone of the planktonic grazer Daphnia carinata in an offspring environment where cyanobacteria were present, but not for two additional clones. Offspring from mothers exposed to M. aeruginosa had lower intrinsic rates of population increase, average life span, and net reproductive rates than individuals from unexposed mothers when fed exclusively a green alga. These results suggest that benefits, costs, and clonal variations of maternal effects of inducible tolerance should be considered when trying to understand ecological consequences of cyanobacterial blooms since they can shape the trophic interactions between cyanobacteria and daphnids.
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