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11.
Ceri J. Vincent Niels E. Poulsen Zeng Rongshu Dai Shifeng Li Mingyuan Ding Guosheng 《International Journal of Greenhouse Gas Control》2011,5(3):598-603
The storage potential of selected sites within the Bohai Basin was assessed for the COACH project. The Gangdong oilfield is considered to have a small potential storage capacity (23 Mt) and to be possibly suitable for an enhanced oil recovery or small-scale storage pilot rather than large-scale storage. The Shengli oilfield province is considered to have a great potential storage capacity (472 Mt in eight selected fields), however, these fields, like those of the Gangdong oilfield province, are compartmentalised by faulting and stratigraphy and likely to be quite challenging for injection. Unmineable coal seams in the Kailuan mining area were also considered for storage, the estimated capacity is 504 Gt adsorbed onto the coal and 38,100 Mt void storage capacity. However, the coals have low porosity and permeability, so they would be expected to have poor injectivity. This is also an active mining area and so any storage site would have to be chosen carefully to avoid affecting future energy resources. The Huimin sub-basin within the Jiyang Depression was identified for consideration as an aquifer storage site; the Guantao Formation has good porosity and permeability in this region, and the regional-level storage capacity of these areas was estimated to be 0.7 Gt. The aquifers in the Huimin sub-basin appear promising for storage, however, less data are available than for the oilfields and the sealing formations are not directly proven to trap buoyant fluids, though in adjacent oilfield in the Shengli oilfield province, the Minghuazhen Formation forms a regional seal for the Guantao Formation. 相似文献
12.
Freddie-Jeanne Richard Michael Poulsen Abraham Hefetz Christine Errard David R. Nash Jacobus J. Boomsma 《Behavioral ecology and sociobiology》2007,61(11):1637-1649
Cuticular hydrocarbon profiles are essential for nestmate recognition in insect societies, and quantitative variation in these
recognition cues is both environmentally and genetically determined. Environmental cues are normally derived from food or
nest material, but an exceptional situation may exist in the fungus-growing ants where the symbiotic fungus garden may be
an independent source of recognition compounds. To investigate this hypothesis, we quantified the chemical profiles of the
fungal symbionts of 18 sympatric colonies of Acromyrmex echinatior and Acromyrmex octospinosus and evaluated the quantitative variation of the 47 compounds in a multivariate analysis. Colony-specific chemical profiles
of fungal symbionts were highly distinct and significantly different between the two ant species. We also estimated the relative
genetic distances between the fungal symbionts using amplified fragment length polymorphism (AFLP) and correlated these with
the overall (Mahalanobis) chemical distances between the colony-specific profiles. Despite the standardized laboratory conditions,
the correlations were generally weak, but a statistically significant portion of the total variation in chemical profiles
could be explained by genetic differences between the fungal symbionts. However, there was no significant effect of ant species
in partial analyses because genetic differences between symbionts tend to coincide with being reared by different ant species.
However, compound groups differed significantly with amides, aldehydes, and methyl esters contributing to the correlations,
but acetates, alkanes, and formates being unrelated to genetic variation among symbionts. We show experimentally that workers
that are previously exposed to and fed with the fungal symbiont of another colony are met with less aggression when they are
later introduced into that colony. It appears, therefore, that fungus gardens are an independent and significant source of
chemical compounds, potentially contributing a richer and more abundant blend of recognition cues to the colony “gestalt”
than the innate chemical profile of the ants alone.
Freddie-Jeanne Richard and Michael Poulsen contributed equally to this work. 相似文献
13.
Michael Poulsen Adrianne N. Bot Mogens G. Nielsen Jacobus J. Boomsma 《Behavioral ecology and sociobiology》2002,52(2):151-157
The paired exocrine metapleural glands present in the large majority of ant species produce compounds with antibiotic properties. In the leaf-cutting ant, Acromyrmex octospinosus, the secretion consists of more than 20 different compounds and it has generally been assumed that the glands serve as a general defence against various infectious microbes of fungal and bacterial origin. We present results illuminating the direct costs and benefits of these metapleural gland defences in A. octospinosus. We show that major workers of this leaf-cutting ant experience a significant reduction in their respiration rate when the metapleural glands are experimentally closed, indicating that metapleural gland secretion incurs a substantial cost and that the production of compounds from these glands is terminated when the ants are incapable of secreting them. In another set of experiments, we show that the ability to secrete antibiotic compounds from the metapleural glands is of significant importance when ants are exposed to a general but potentially virulent insect pathogen, Metarhizium anisopliae. Infection with this fungus is lethal within a few days when ants have their metapleural glands experimentally closed, but relatively harmless when the metapleural glands are functional. These findings support experimentally the view that the metapleural glands play an important hygienic role in leaf-cutting ants. 相似文献
14.
Svend Byrial Poulsen 《Waste management & research》2007,25(3):283-287
Odense Waste Management Company Ltd. (OWMC) covers the municipality of Odense having around 185 000 inhabitants. It is a not-for-profit company, in which all services are paid for by the users. OWMC is increasingly participating in international development activities, particularly within training and operational support. This is mainly driven by the staff, who think it is important, interesting, challenging and fun to contribute their know-how elsewhere. The main approach applied, when training and practice is undertaken for OWMC's own staff as well as for international cooperation partners, is to keep things simple and easily understandable, even if there may sometimes be rather complex processes and activities involved. So far, OWMC has in 2003-2005 participated in a project for the municipalities of Koszalin and Slupsk in Northern Poland, and in 2005-2007 in a project for the newly established solid waste management departments of Beni Suef and El Fashn cities in Egypt. Would it be possible to create a future waste management sector with more know-how sharing mechanisms in place, and might the establishment of a capacity building working group or networking forum, for example, within the framework of ISWA be an important step forward in this context? Why not just start now? 相似文献
15.
The loss of animals in tropical forests may alter seed dispersal patterns and reduce seedling recruitment of tree species, but direct experimental evidence is scarce. We manipulated dispersal patterns of Manilkara mabokeensis, a monkey-dispersed tree, to assess the extent to which spatial distributions of seeds drive seedling recruitment. Based on the natural seed shadow, we created seed distributions with seeds deposited under the canopy ("no dispersal"), with declining density from the tree ("natural dispersal"), and at uniform densities ("good dispersal"). These distributions mimicked dispersal patterns that could occur with the extirpation of monkeys, low levels of hunting, and high rates of seed dispersal. We monitored seedling emergence and survival for 18 months and recorded the number of leaves and damage to leaves. "Good dispersal" increased seedling survival by 26%, and "no dispersal" decreased survival by 78%, relative to "natural dispersal." Using a mixed-effects survival model, we decoupled the distance and density components of the seed shadow: seedling survival depended on the seed density, but not on the distance from the tree. Although community seedling diversity tended to decrease with longer dispersal distances, we found no conclusive evidence that patterns of seed dispersal influence the diversity of the seedling community. Local seed dispersal does affect seedling recruitment and survival, with better dispersal resulting in higher seedling recruitment; hence the loss of dispersal services that comes with the reduction or extirpation of seed dispersers will decrease regeneration of some tree species. 相似文献
16.
In tropical forests, resource-based niches and density-dependent mortality are mutually compatible mechanisms that can act simultaneously to limit seedling populations. Differences in the strengths of these mechanisms will determine their roles in maintaining species coexistence. In the first assessment of these mechanisms in a Congo Basin forest, we quantified their relative strengths and tested the extent to which density-dependent mortality is driven by the distance-dependent behavior of seed and seedling predators predicted by the Janzen-Connell hypothesis. We conducted a large-scale seed addition experiment for five randomly selected tropical tree species, caging a subset of seed addition quadrats against vertebrate predators. We then developed models to assess the mechanisms that determine seedling emergence (three months after seed addition) and survival (two years after seed addition). As predicted, both niche differentiation and density-dependent mortality limited seedling recruitment, but predation had the strongest effects on seedling emergence and survival. Seedling species responded differently to naturally occurring environmental variation among sites, including variation in light levels and soil characteristics, supporting predictions of niche-based theories of tropical tree species coexistence. The addition of higher densities of seeds into quadrats initially led to greater seedling emergence, but survival to two years decreased with seed density. Seed and seedling predation reduced recruitment below levels maintained by density-dependent mortality, an indication that predators largely determine the population size of tree seedlings. Seedling recruitment was unrelated to the distance to or density of conspecific adult trees, suggesting that recruitment patterns are generated by generalist vertebrate herbivores rather than the specialized predators predicted by the Janzen-Connell hypothesis. If the role of seed and seedling predation in limiting seedling recruitment is a general phenomenon, then the relative abundances of tree species might largely depend on species-specific adaptations to avoid, survive, and recover from damage induced by vertebrate herbivores. Likewise, population declines of herbivorous vertebrate species (many of which are large and hunted) may trigger shifts in species composition of tropical forests. 相似文献
17.
Ksawery Kuligowski Tjalfe G Poulsen Peder Stoholm Niels Pind Jens Laursen 《Waste management & research》2008,26(4):347-354
Ash from pig manure treated by combustion and thermal gasification was characterized and compared in terms of nutrient, i.e., potassium (K), phosphorus (P) and heavy metal, i.e., cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni) and zinc (Zn) contents. Total nutrient and metal concentrations were measured using energy dispersive X-ray fluorescence analysis. Acid (HNO3, H2SO4) and water-extractable concentrations were also measured both in non-classified ash and in selected ash particle size fractions using flame atomic absorption spectrometry and colorimetric spectrometry. Results indicate that ash from gasified manure contained more water-extractable K in comparison with combusted manure whereas the opposite was the case with respect to P. Heavy metals Ni, Cr and Cd were present in higher concentrations in the fine particle size fractions (< 30 microm of particle diameter), whereas K, P, Zn and Cu exhibited higher concentrations in the coarser particle size fractions (> 30 microm). 相似文献
18.
Compost air permeability controls air flow through compost during composting or when using compost as biofilter material. Air permeability is therefore an important characteristic of compost. The relationships between air permeability (k(a)) in compost and compost dry bulk density (rho b), gravimetric water content (omega), and volumetric air content (epsilon) was investigated for two types of composts. The composts used were produced from a digested sewage sludge-straw mixture and from garden waste and measurements were conducted on sieved and repacked 100 cm3 compost samples. Results showed a linear relation between log(k(a)) and rho b at constant values of omega for both composts, indicating an exponential relationship between k(a) and rho b. The slopes of these relationships generally became more negative with increasing rho b. The results further showed a linear relationship between log(k(a)) and log(epsilon) for both composts as also often observed for soils. It was observed that the log(k(a)) and log(epsilon) relationships for the garden waste compost all intercepted at the same location despite having very different slopes. This means that it is possible to predict the entire k(a)-epsilon relationship using only one measurement of corresponding (k(a), epsilon) for garden waste. It was not possible to determine whether this was also the case for the sewage sludge compost due to difficulties in sample preparation at low and high water content. 相似文献
19.
John R. Poulsen Cooper Rosin Amelia Meier Emily Mills Chase L. Nuñez Sally E. Koerner Emily Blanchard Jennifer Callejas Sarah Moore Mark Sowers 《Conservation biology》2018,32(3):559-567
Poaching is rapidly extirpating African forest elephants (Loxodonta cyclotis) from most of their historical range, leaving vast areas of elephant‐free tropical forest. Elephants are ecological engineers that create and maintain forest habitat; thus, their loss will have large consequences for the composition and structure of Afrotropical forests. Through a comprehensive literature review, we evaluated the roles of forest elephants in seed dispersal, nutrient recycling, and herbivory and physical damage to predict the cascading ecological effects of their population declines. Loss of seed dispersal by elephants will favor tree species dispersed abiotically and by smaller dispersal agents, and tree species composition will depend on the downstream effects of changes in elephant nutrient cycling and browsing. Loss of trampling and herbivory of seedlings and saplings will result in high tree density with release from browsing pressures. Diminished seed dispersal by elephants and high stem density are likely to reduce the recruitment of large trees and thus increase homogeneity of forest structure and decrease carbon stocks. The loss of ecological services by forest elephants likely means Central African forests will be more like Neotropical forests, from which megafauna were extirpated thousands of years ago. Without intervention, as much as 96% of Central African forests will have modified species composition and structure as elephants are compressed into remaining protected areas. Stopping elephant poaching is an urgent first step to mitigating these effects, but long‐term conservation will require land‐use planning that incorporates elephant habitat into forested landscapes that are being rapidly transformed by industrial agriculture and logging. 相似文献
20.
Seven-day static renewal tests with Ceriodaphnia dubia were used to document the chronic toxicity of ethylene glycol ethers and acetates to this invertebrate. The 7-d EC10 (effective concentrations inducing an inhibition of 10% of the reproduction of the tested organisms) values ranged from 0.06 to 1025 mg/l. While a survey of the literature showed that the acute toxicity of these chemicals appeared negligible, our results clearly revealed the potential chronic effects of some of them to this organism occupying an important trophic level in the aquatic ecosystems. The usefulness of this kind of test to better estimate the adverse effects of glycol ethers was stressed. 相似文献