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601.
Climate change is expected to cause an increased frequency of extreme events such as heavy floods and major storms. Such stochastic events have an immediate impact on surface water quality, but the long-term effects are largely unknown. In this study, we assess long-term monitoring data from two Swedish headwater catchments affected by extreme weather events. At one site, where nitrogen effects in soil water, groundwater, and stream water were studied after storm-felling and subsequent forest dieback from bark beetle attack, long-term (>5 years) but relatively modest (generally <1 mg L?1) increases in ammonium (NH4-N) and nitrate (NO3-N) concentrations were observed in the various aqueous media. At the other site, where effects on benthic fauna were studied in a stream impacted by extreme geophysical disturbances caused by rainstorm-induced flashflood, only short-term (1 year) effects were revealed both regarding diversity and composition of species. 相似文献
602.
David G. Angeler Craig R. Allen Hannah E. Birgé Stina Drakare Brendan G. McKie Richard K. Johnson 《Ambio》2014,43(1):113-125
Freshwater ecosystems are important for global biodiversity and provide essential ecosystem services. There is consensus in the scientific literature that freshwater ecosystems are vulnerable to the impacts of environmental change, which may trigger irreversible regime shifts upon which biodiversity and ecosystem services may be lost. There are profound uncertainties regarding the management and assessment of the vulnerability of freshwater ecosystems to environmental change. Quantitative approaches are needed to reduce this uncertainty. We describe available statistical and modeling approaches along with case studies that demonstrate how resilience theory can be applied to aid decision-making in natural resources management. We highlight especially how long-term monitoring efforts combined with ecological theory can provide a novel nexus between ecological impact assessment and management, and the quantification of systemic vulnerability and thus the resilience of ecosystems to environmental change. 相似文献
603.
Restoration of acidified lakes by liming does not, in many cases, improve productivity to a pre-acidified state. We hypothesize that the poor recovery detected in many of these lakes is due to constrained in-lake phosphorous (P) cycling caused by enhanced precipitation of metals in higher pH, limed waters. Long-term (1990–2012) data for 65 limed, circum-neutral (pH 6–8), and acidified lakes in Sweden were analyzed to determine trends for P and potential drivers of these trends. Limed lakes not only had lower mean values and stronger decreasing trends for total P than non-limed lakes, but they also had the highest percentage of decreasing trends (85 %). A P release factor (Hypolimnetic P/Epilimnetic P) was developed to elucidate differences in internal P cycling between lake groups. Consistently, lower P release factors in limed lakes show limitation of internal P cycling during summer months that may be a factor limiting P bioavailability and thus productivity of these systems. 相似文献
604.
Kai Zhao Huaming Guo 《Environmental science and pollution research international》2014,21(3):1944-1953
Activated natural siderite (ANS) was used to investigate its characteristics and mechanisms of As(V) adsorption from aqueous solution. Batch tests were carried out to determine effects of contact time, initial As(V) concentration, temperature, pH, background electrolyte, and coexisting anions on As(V) adsorption. Arsenic(V) adsorption on ANS well-fitted pseudo-second-order kinetics. ANS showed a high-adsorption capacity of 2.19 mg/g estimated from Langmuir isotherm at 25 °C. Thermodynamic studies indicated that As(V) adsorption on ANS was spontaneous, favorable, and endothermic. ANS adsorbed As(V) efficiently in a relatively wide pH range between 2.0 and 10.0, although the removal efficiency was slightly higher in acidic conditions than that in basic conditions. Effects of background electrolyte and coexisting anions were not significant within the concentration ranges observed in high As groundwater. Results of XRD and Fe K-edge XANES analysis suggested ANS acted as an Fe(II)/(III) hybrid system, which was quite effective in adsorbing As from aqueous solution. There was no As redox transformation during adsorption, although Fe(II) oxidation occurred in the system. Two infrared bands at 787 and 872 cm?1 after As(V) adsorption suggested that As(V) should be predominantly adsorbed on ANS via inner-sphere bidendate binuclear surface complexes. 相似文献
605.
Vincent Bartolomei Matthias Sörgel Sasho Gligorovski Elena Gómez Alvarez Adrien Gandolfo Rafal Strekowski Etienne Quivet Andreas Held Cornelius Zetzsch Henri Wortham 《Environmental science and pollution research international》2014,21(15):9259-9269
Gaseous nitrogen dioxide (NO2) represents an oxidant that is present in relatively high concentrations in various indoor settings. Remarkably increased NO2 levels up to 1.5 ppm are associated with homes using gas stoves. The heterogeneous reactions of NO2 with adsorbed water on surfaces lead to the generation of nitrous acid (HONO). Here, we present a HONO source induced by heterogeneous reactions of NO2 with selected indoor paint surfaces in the presence of light (300 nm?<?λ?<?400 nm). We demonstrate that the formation of HONO is much more pronounced at elevated relative humidity. In the presence of light (5.5 W m?2), an increase of HONO production rate of up to 8.6?·?109 molecules cm?2 s?1 was observed at [NO2]?=?60 ppb and 50 % relative humidity (RH). At higher light intensity of 10.6 (W m?2), the HONO production rate increased to 2.1?·?1010 molecules cm?2 s?1. A high NO2 to HONO conversion yield of up to 84 % was observed. This result strongly suggests that a light-driven process of indoor HONO production is operational. This work highlights the potential of paint surfaces to generate HONO within indoor environments by light-induced NO2 heterogeneous reactions. 相似文献
606.
Anuluxshy Balasubramaniyam Patricia J. Harvey 《Environmental science and pollution research international》2014,21(22):12651-12661
The choice of plant for phytoremediation success requires knowledge of how plants respond to contaminant exposure, especially their roots which are instrumental in supporting rhizosphere activity. In this study, we investigated the responses of plants with different architectures represented by beetroot (Beta vulgaris), a eudicot with a central taproot and many narrower lateral roots, and tall fescue (Festuca arundinacea), a monocot possessing a mass of threadlike fibrous roots to grow in crude oil-treated sand. In this paper, scanning electron microscopy was used to investigate modifications to plant root structure caused by growth in crude oil-contaminated sand. Root structural disorders were evident and included enhanced thickening in the endodermis, increased width of the root cortical zone and smaller diameter of xylem vessels. Inhibition in the rate of root elongation correlated with the increase in cell wall thickening and was dramatically pronounced in beetroot compared to the roots of treated fescue. The latter possessed significantly fewer (p?<?0.001) and significantly shorter (p?<?0.001) root hairs compared to control plants. Possibly, root hairs that absorb the hydrophobic contaminants may prevent contaminant absorption into the main root and concomitant axile root thickening by being sloughed off from roots. Tall fescue exhibited greater root morphological adaptability to growth in crude oil-treated sand than beetroot and, thus, a potential for long-term phytoremediation. 相似文献
607.
There is much discussion within the sustainable development community regarding climate stabilization and particularly, finding
environmentally equitable ways to address emission reductions. Knowing the current level of emission is only one variable
in this complex picture. While the rate of emissions is clearly a problem, the overall increase in GHG concentration in the
atmosphere is ultimately the main driver of anthropogenic warming. Therefore, it is also important to understand the cumulative
emissions, those which have taken us to the current condition. This research presents a case study of six countries to compare
the emissions per capita and cumulative emissions during the past 200 years. It is known that carbon emissions are closely
related to economic activities, but here we show that some countries have reached per capita emissions plateaus at different
levels while others are still rising. Specifically, one approach toward socioeconomic development, in terms of energy–economy,
reaches a plateau at 10 Mt carbon per person, which the United Kingdom and South Korea have attained. The US occupies another
emission regime at 20 Mt carbon per person. Developing economies such as India and China are considerably below these levels,
and unless they follow other integrated economic/environmental solutions, they will continue to increase their per capita
emissions during development. 相似文献
608.
Keigo Akimoto Fuminori Sano Takashi Homma Kenichi Wada Miyuki Nagashima Junichiro Oda 《Sustainability Science》2012,7(2):157-168
This study focuses on analyses of greenhouse gas (GHG) emission reductions, from the perspective of interrelationships among
time points and countries, in order to seek effective reductions. We assessed GHG emission reduction potentials and costs
in 2020 and 2030 by country and sector, using a GHG emission reduction-assessment model of high resolution regarding region
and technology, and of high consistency with intertemporal, interregional, and intersectoral relationships. Global GHG emission
reduction potentials relative to baseline emissions in 2020 are 8.4, 14.7, and 18.9 GtCO2eq. at costs below 20, 50, and 100 $/tCO2eq., corresponding to +19, −2, and −7 %, respectively, relative to 2005. The emission reduction potential for 2030 is greater
than that for 2020, mainly because many energy supply and energy-intensive technologies have long lifetimes and more of the
current key facilities will be extant in 2020 than in 2030. The emission reduction potentials in 2030 are 12.6, 22.0, and
26.6 GtCO2eq. at costs below 20, 50, and 100 $/tCO2eq., corresponding to +19, −2, and −7 %, respectively, relative to 2005. The emission reduction potential for 2030 is greater
than that for 2020, mainly because many energy supply and energy-intensive technologies have long lifetimes and more of the
current key facilities will be extant in 2020 than in 2030. The emission reduction potentials in 2030 are 12.6, 22.0, and
26.6 GtCO2eq. at costs below 20, 50, and 100 /tCO2eq., corresponding to +33, +8, and −3 %, respectively, relative to 2005. Global emission reduction potentials at a cost below
50 $/tCO2eq. for nuclear power and carbon capture and storage are 2.3 and 2.2 GtCO2eq., respectively, relative to baseline emissions in 2030. Longer-term perspectives on GHG emission reductions toward 2030
will yield more cost-effective reduction scenarios for 2020 as well. 相似文献
609.
Pinus roxburghii (chir-pine) and Quercus leucothchophora (banj-oak) are dominant forests of mountainous part of the Uttarakhand Himalaya. The continued anthropogenic disturbance
is opening the canopy, forming canopy gaps and as a result forest fragments are developing. Thus, the present study aims to
analyze variations in species richness and vegetational parameters in relation to canopy gaps in forests. Total species richness
was greater in open canopied forest compared to moderate and close canopied forests. In comparison between oak and pine forest,
it was greater in oak forest while the proportion of common species was low between oak—pine forests. Mean species richness
did not significantly vary from one canopy gap to another as well as in oak and pine dominated forest. This indicated that
dominant forest types played an important role to form the community structure. The shrubs richness were greater in closed
canopy and between the forests it was greater in pine forest. Tree and shrub density was low in open canopy while herb density
was high in moderate canopy. Thus, this study indicated that the dominant canopy species play an important role in deciding
the community structures especially the distribution of under canopy species. These parameters should be considered for conservation
and maintenance of plant biodiversity of a region. 相似文献
610.
Silvana Kuhtz 《Environment, Development and Sustainability》2011,13(1):79-85
Climate is one of the more complex physical systems in nature, its behaviour being fundamentally non-linear and chaotic. In
assessing the potential risks from climate change and the costs of averting it, researchers and policymakers encounter pervasive
uncertainty. Sceptics demand to get rid of the inherent uncertainties, and some experts, on the other end, keep sending out
messages of catastrophic scenarios hoping that this will increase people’s awareness of the danger we face. The recent admission
of a mistake in IPCC’s Climate change 2007 report (promptly broadcast by all the major media groups and newspapers from Jan. 20th 2010 onwards) made by the head of
the Intergovernmental Panel on Climate Change—that Himalayan glaciers could melt away by 2035 (the IPCC claim of 2035 is wrong
by over 300 years.)—has already brought a damage to the IPCC’s reputation that is likely to be considerable. But in this paper,
perhaps risking being provocative and paradoxical, instead of looking for the right answers to what we think are inevitable uncertainties, we intend to search for new questions that may lead to a new way of
thinking and may bring about new lifestyles and behaviour for citizens and firms. 相似文献