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31.
The Early Christian Munazio Ireneo cubicle in Cagliari (Sardinia) is carved into the rock and is one of the rare monuments of Sardinia belonging to Early Christian Age. It is 166 cm under the planking level and is a semi-confined chamber in which a gate allows exchange with the outside. In 1888, when it was discovered, it was completely painted, but over the years, it suffered a serious damage and all the paintings are nearly disappeared. Now the site shows a high moisture and a differential damage characterised by delamination, powdering, salt crystallisation and biological colonisation. The research offers a multidisciplinary approach to study the salt crystallisation damage, which is a phenomenon still not completely understood today. Studies and analyses highlight that different kinds of damage can be recognised. The cement mortar and the air pollution cause crystallisation of the sulphates. Constant capillary rising and the presence of water infiltration due to the rains, which travelled into the site from the vault, were detected during qualitative inspection. Although the microclimate did not change much in the site and the humidity was almost constant during the monitoring period, the variations in temperature allowed the phase transitions of sodium sulphate, especially in summer. The greatest damage of the porous stone is associated with the phase transitions and crystallisation inside the stone of sodium sulphate, one of the most harmful salts for porous materials because of its high crystallisation pressure. 相似文献
32.
Angeliki Mentzafou Chrysa Vamvakaki Ierotheos Zacharias Areti Gianni Elias Dimitriou 《Environmental Earth Sciences》2017,76(6):259
The Spercheios river basin—coastal marine area is a complex natural and interdependent ecosystem, highly affected by human activities and interventions. Such sensitive systems are even more vulnerable to alterations of the hydrological cycle components and it is likely to be rapidly and severely affected by climate change. In order to examine the climate change impacts on water resources of the study area, the interaction between the hydrology of the river basin and the hydrodynamic of the coastal marine area was examined using two models. Based on the results, although the irrigation needs decrease for the years 2050 and 2100 due to corresponding decrease in cultivated areas, temperature increase and precipitation decrease are both expected to influence the water resources of the Spercheios river basin, which will directly affect the Maliakos Gulf hydrodynamics. The necessity to adopt a holistic approach which will treat river basins and coastal marine areas as an integrated whole, with regard to environmental, socio-economic and political framework, is evident. 相似文献
33.
Andrew Liddle, Pia Mukherjee and David Parkinson discuss the new precision available to cosmological modellers. 相似文献
34.
Ilias Bertahas Elias Dimitriou Ioannis Karaouzas Sofia Laschou Ierotheos Zacharias 《洁净——土壤、空气、水》2006,34(4):349-359
Trichonis Lake is the largest natural freshwater body in Greece with a surface area of 97 km2. It receives pollutants from numerous anthropogenic activities, especially from intensive agricultural practices, urban sewages, stock grazing land and small industries. In this study, hydrologic and chemical parameters are assessed during two periods (1990–1991) and (2001–2002) to evaluate the effects of the climatic changes on phosphorous trends and consequently on the trophic status of Trichonis Lake. Even though large quantities of fertilizers are applied in the lake's catchment, phosphorus loads are still in the permissible level as estimated according to Vollenweider's relationship based on total phosphorus concentration. Due to relatively higher rainfall precipitation during the last years, an increased amount of the phosphorus entering into the lake system is flushed out, thus keeping the trophic status of the lake in oligotrophic levels. In contrast, lower rainfall rates during the first period (1990–1991) have led to the decrease in phosphorus flush out and its detainment into the lake water and sediment resulting to mesotrophic conditions. As the trophic status of the lake is mainly hydrologically dependent and thus unpredictable, effective management plans targeting the elimination of nutrient pollution loadings are necessary. 相似文献
35.
Peter Edwards Lisa Sharma‐Wallace Tim Barnard Sandra J. Velarde Tui Warmenhoven Gerard Fitzgerald Duncan Harrison Loretta Garrett Tina Porou Pia Pohatu 《New Zealand geographer》2019,75(2):63-73
Sustainable livelihoods approaches used in international development are applied to a vulnerable New Zealand catchment. The Waiapu Catchment has a high proportion of indigenous residents, and is one of the most remote and deprived areas in the country. Linear and centralised approaches to indigenous development have failed to bring about desired changes. We identify “capitals” (social, human/political, physical, natural, financial and cultural) present in the catchment. From this assessment, we propose capital‐based holistic approaches to bring about community‐led change. The assessment and resulting approaches can be used in other vulnerable environments around the world. 相似文献
36.
By enhancing the stock of piscivorous fish in a whole-lake experiment in Gräfenhain (Germany) since 1981 to such an extent that almost all planktivorous fish were exterminated, we examined the concept of “over-biomanipulation”. This hypothesis predicts that (a) extremely strong piscivory will allow uncontrolled development of large invertebrate predators and (b) these invertebrates can exert the same strong predation pressure on large herbivorous zooplankton as planktivorous fish. The hypothesis is tested the first time by a cross-comparison of the long-term response of the plankton community structure in the experimental lake (Piscivore L.) with (1) the intermediate response in the same lake and with (2) that of the long-term state in a nearby reference lake (Planktivore L.) densely inhabited by planktivorous fish (Leucaspius delineatus, a small cyprinid). The intermediate (1989–1992) response in Piscivore L. revealed a strong increase of the abundance of the invertebrate predator Chaoborus flavicans. Large daphnids were able to coexist with C. flavicans so that edible phytoplankton were suppressed and water transparency increased.As part (a) of the hypothesis predicts, the long-term response in Piscivore L. was characterized by the immigration of the larger predator Chaoborus obscuripes which displaced the smaller C. flavicans completely. The results support also part (b) of the hypothesis of “over-biomanipulation”: C. obscuripes-dominated Piscivore L. showed not much difference in biomasses of daphnids and total and edible phytoplankton as well as Secchi depth compared with fish-dominated Planktivore Lake. On the other hand, C. obscuripes-dominated Piscivore L. was characterized by distinctly lower biomass of daphnids, mean body volume of all crustaceans and Secchi depth as well as by higher biomass of edible phytoplankton compared with C. flavicans-dominated Piscivore Lake. We conclude that long-lasting success of biomanipulation cannot be achieved by extremely high piscivory leading to the almost complete extermination of planktivorous fish. 相似文献
37.
38.
Arno Rein Steffen Popp Steffen Zacharias Carsten Leven Martin Bittens Peter Dietrich 《Environmental Earth Sciences》2011,63(6):1239-1249
The present work focuses on approaches for the characterization of subsurface contamination, which need to be reliable and
cost-effective, particularly for extended and remote areas aimed at being redeveloped. Requirements are discussed with respect
to specific conditions at megasites, in order to enable site valorization. In a case study, two approaches are compared, comprising
(1) conventional site investigation based on historical surveys and concentration measurements at monitoring wells installed
in areas suspected of being polluted and (2) the use of direct push (DP) methods covering the complete area. The DP investigation
provided information on the contamination distribution and yielded also important information on hydraulic conditions. Statistical
analysis of the results applying indicator kriging revealed that the conventional approach is markedly risky when decision-making
relies solely on historical and sparse data. The DP campaign remarkably reduced the uncertainty concerning the estimated occurrence
of polluted groundwater at the whole site. Furthermore, monitoring measurements are analyzed showing the possible importance
of temporal variability. Taking economical consideration into account, DP-based groundwater screening is recommended to obtain
either first or complementary information on the entire site. Based on these data, also locations for a long-term monitoring
could be selected if temporal variability is assumed relevant. 相似文献
39.
Alessio Langella Domenico Calcaterra Piergiulio Cappelletti Abner Colella Maria Pia D’Albora Vincenzo Morra Maurizio de Gennaro 《Environmental Earth Sciences》2009,59(1):145-160
Results of a research carried out on the lavas from Campi Flegrei and Somma-Vesuvius volcanic districts are reported here.
The lavas have been widely employed, since Roman age, in several important monumental buildings of the Campania region, mainly
in the town of Naples and in its province. They are classified as trachytes (Campi Flegrei products), tephri-phonolites and
phono-tephrites (Somma-Vesuvius complex) from a petrographical point of view. Sampling was carried out from well-known exploitation
districts. A substantial chemical difference between the products of the two sectors was confirmed, while petrophysical characterization
evidenced similarity among the two different materials, although some differences were recorded even in samples coming from
the same exploitation site. 相似文献
40.
A mathematical model is proposed to simulate brackish karstic springs. Rainfall data constitutes model input information while output information is the discharge and the chloride concentration of the water versus time. The model was constructed by considering the mass and mechanical energy balance on the hydrodynamic analog, which includes three reservoirs outflowing in a tube that lies adjacent to the spring. Two reservoirs emulate the karstic system, and the third one emulates the sea. The discharge of the spring is given by the sum of the discharge of the reservoirs, and the chloride concentration by the solution of the mixing problem between the fresh and the salty water, which exists in the tube leading to the spring. The model is applied to the spring of Almiros at Heraklion, Crete, Greece. The agreement between model values and field measurements is very good for depletion periods and satisfactory for recharge periods. 相似文献