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For the time being, simple and reliable methods which permit the imaging of the complex topography of contaminant plumes in groundwater are missing. The conventional methods for the punctual determination of contaminant concentrations cannot fulfill this demand. To successfully implement and utilize. Natural Attenuation, these deficits have to be overwhelmed. The detectors described in the following represent only part of the probing device system the authors have developed; it shall enable their user to image different aspects of plume topography and its time dependent change by monitoring within the undisturbed groundwater aquifer in groundwater measuring levels: ? relative freights of contaminants and trace contaminants by passive samplers [4] and ? redox milieu parameters by detectors. The detectors offer multi-purpose, tape-like probing devices of unlimited length. They are charged with a defined reserve of reactive substances. During monitoring actions, the derector tape hangs vertically stretched by a weight preferably covering from the top to the bottom of the whole water column. During the reaction period, the detector may be relaunched for repeated visual inspection. The colour changes of the detectors enable the identification of a row of parameters in the vertically (depth-) oriented profile by unbroken optical/visually perceivable imaging: ? Position of Redox potential thresholds for Mn-IV-Mn-II, Fe-III-Fe-II, Sulfate-Sulfide ? Position of ochre precipitation and iron-sulfide precipitation horizons ? Relative freights of the sum of substances effecting reduction (period until defined oxidant reserve has been reduced) ? Relative freights of the sum of substances effecting iron-sulfide oxidation (period until defined reductant reserve has been reduced) ? Position of dissolved iron-II ions containing horizons ? Position of dissolved hydrogen-sulfide ions/hydrogen-sulfide containing horizons ? Relative freights of iron-II ions (period until defined oxidant reserve has been reduced) ? Relative freights of hydrogen-sulfide ions/hydrogen-sulfide (period until defined oxidant reserve has been reduced). Furthermore, the detectors are also suitable for the examination of waters even of great depth, as for example artificial or natural lakes, sea and ocean basins. 相似文献
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Heterospecific matings are generally assumed to be unconditionally disadvantageous due to reduced viability or fertility of
hybrid offspring. For female collared flycatchers (Ficedula albicollis) mated to male pied flycatchers (Ficedula hypoleuca), the cost of heterospecific pair formation is reduced due to high levels of conspecific extra-pair paternity and a male-biased
offspring sex ratio. In order to investigate whether these cost-reducing mechanisms are the result of female mating strategies,
rather than being a by-product of species incompatibilities, we manipulated the plumage of male collared flycatchers before
pair formation to make them resemble male pied flycatchers. Since species incompatibilities are absent in this design, any
systematic effect of manipulation on sex ratio or paternity would indicate a role of female mating strategy. Paternity was
determined by means of a likelihood approach that controls the errors made in assigning a chick to be ‘within-pair’ or ‘extra-pair’.
Neither the sex ratio nor the male share of paternity was affected by the manipulation in a systematic manner. We therefore
conclude that our experimental data provide no support for the suggestion that female behavioural strategies are markedly
adjusted in response to formation of mixed-species pairs.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
117.
Sediment-dwelling zoobenthos stimulate the mineralization of organic matter and alter nutrient cycling by aerating the sediment via burrows, by feeding on detritus, and by redistributing particles. Here we experimentally revealed that abundant benthic chironomids (Chironomus riparius) can perceive predatory fish (Rutilus rutilus) via chemical cues (kairomones) and spend less time foraging at the sediment surface and more time hiding in their burrows. This predator avoidance behavior significantly increased the exposure of freshly deposited organic particles to oxygen by reducing their burial to subsurface layers and by enhancing the aeration of subsurface layers via burrow ventilation, conditions that together increased the rate of organic matter mineralization. These results demonstrate that predatory fish can exert trait-mediated effects on benthic communities that in turn alter basic ecosystem processes related to nutrient cycling. 相似文献
118.
Ivan Jarić Céline Bellard Ricardo A. Correia Franck Courchamp Karel Douda Franz Essl Jonathan M. Jeschke Gregor Kalinkat Lukáš Kalous Robert J. Lennox Ana Novoa Raphaël Proulx Petr Pyšek Andrea Soriano–Redondo Allan T. Souza Reut Vardi Diogo Veríssimo Uri Roll 《Conservation biology》2021,35(2):447-451
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Ena Smidt Katharina Meissl Johannes Tintner Franz Ottner 《Environmental Chemistry Letters》2010,8(3):217-222
Quantification of carbonate contents in fresh and weathered municipal solid waste incinerator (MSWI) bottom ash was performed
using volumetric and gravimetric methods, Fourier Transform Infrared (FT-IR) spectroscopy and thermal analysis. Results differ
considerably depending on the method applied. Volumetric measurement and thermogravimetry (TG) are based on the determination
of CO2 release by acid or thermal treatment, respectively. Interactions of CO2 with the mineral matrix and de novo synthesis of carbonates during thermal analysis were observed. In order to find out the
contribution of CO2 released from residual organic matter, an additional experiment was carried out to demonstrate how the material is affected
by the heating process in the course of thermal analysis. FT-IR spectroscopy as a non-destructive method seems to provide
the most reliable quantitative results. 相似文献
120.
Division of labor in social insects is determinant to their ecological success. Recent models emphasize that division of labor is an emergent property of the interactions among nestmates obeying to simple behavioral rules. However, the role of evolution in shaping these rules has been largely neglected. Here, we investigate a model that integrates the perspectives of self-organization and evolution. Our point of departure is the response threshold model, where we allow thresholds to evolve. We ask whether the thresholds will evolve to a state where division of labor emerges in a form that fits the needs of the colony. We find that division of labor can indeed evolve through the evolutionary branching of thresholds, leading to workers that differ in their tendency to take on a given task. However, the conditions under which division of labor evolves depend on the strength of selection on the two fitness components considered: amount of work performed and on worker distribution over tasks. When selection is strongest on the amount of work performed, division of labor evolves if switching tasks is costly. When selection is strongest on worker distribution, division of labor is less likely to evolve. Furthermore, we show that a biased distribution (like 3:1) of workers over tasks is not easily achievable by a threshold mechanism, even under strong selection. Contrary to expectation, multiple matings of colony foundresses impede the evolution of specialization. Overall, our model sheds light on the importance of considering the interaction between specific mechanisms and ecological requirements to better understand the evolutionary scenarios that lead to division of labor in complex systems. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00265-012-1343-2) contains supplementary material, which is available to authorized users. 相似文献