Survival of lichens and bacteria exposed to outer space conditions - Results of the Lithopanspermia experiments     

Rosa de la Torre  Leopoldo G. Sancho  Asunción de los Ríos  Karen Olsson-Francis  Petra Rettberg  Jean-Pierre P. de Vera  Jesus Martinez Frías  Maria Mercedes Lucas  Ana Pintado 《Icarus》2010,208(2):735-292

In the space experiments Lithopanspermia, experimental support was provided to the likelihood of the lithopanspermia concept that considers a viable transport of microorganisms between the terrestrial planets by means of meteorites. The rock colonising lichens Rhizocarpon geographicum and Xanthoria elegans, the vagrant lichen Aspicilia fruticulosa, and endolithic and endoevaporitic communities of cyanobacteria and bacteria with their natural rock substrate were exposed to space for 10 days onboard the Biopan facility of the European Space Agency (ESA). Biopan was closed during launch and re-entry. In addition, in the Stone facility, one sample of R. geographicum on its natural granitic substrate was attached at the outer surface of the re-entry capsule close to the stagnation point, only protected by a thin cover of glass textolite. Post-flight analysis, which included determination of the photosynthetic activity, LIVE/DEAD staining, and germination capacity of the ascospores, demonstrated that all three lichen were quite resistant to outer space conditions, which include the full spectrum of solar extraterrestrial electromagnetic radiation or selected wavelength ranges. This high resistance of the lichens to space appears to be due to their symbiotic nature and protection by their upper pigmented layer, the cortex. In contrast, the rock- or halite-inhabiting bacteria were severely damaged by the same exposure. After atmospheric re-entry, the granite of the Stone sample was transformed into a glassy, nearly homogenous material, with several friction striae. None of the lichen cells survived this re-entry process. The data suggest that lichens are suitable candidates for testing the concept of lithopanspermia, because they are extremely resistant to the harsh environment of outer space. The more critical event is the atmospheric re-entry after being captured by a planet. Experiments simulating the re-entry process of a microbe-carrying meteoroid did not show any survivors.  相似文献   

Environmental and climatic conditions at a potential Glacial refugial site of tree species near the Southern Alpine glaciers. New insights from multiproxy sedimentary studies at Lago della Costa (Euganean Hills, Northeastern Italy)     

Petra Kaltenrieder  Claudio A. Belis  Simone Hofstetter  Brigitta Ammann  Cesare Ravazzi  Willy Tinner   《Quaternary Science Reviews》2009,28(25-26):2647-2662

It has been hypothesized that refugia of thermophilous tree species were located in Northern Italy very close to the Alps, though, this hypothesis has yet to be tested thoroughly. In contrast to Central and Southern Italy with its relative wealth of data, only a few fragmentary records are currently available from Northern Italy for the last Glacial (Würm, Weichselian). Our new study site Lago della Costa lies adjacent to the catchment of the megafans of the Alpine forelands and the braided rivers of the Northeastern Po Plain that have so far inhibited the recovery of continuous Glacial and Late-Glacial records. We analyze pollen, plant macrofossils, charcoal and ostracods to reconstruct the vegetation, fire and lake history for the period 33,000–16,000 cal. BP. We compare our data with Glacial records from Southern Europe to discuss similarities and dissimilarities between these potential refugial areas. A comparison with independent paleoclimatic proxies allows to assess potential linkages between environmental and climatic variability. New macrofossil and pollen data at Lago della Costa unambiguously document the local persistence of boreal tree taxa such as Larix decidua and Betula tree species around the study site during the last Glacial. The regular occurrence of pollen of temperate trees in the organic lake sediments (fine-detritus calcareous gyttja) suggests that temperate taxa such as Corylus avellana, Quercus deciduous, Tilia, Ulmus, Fraxinus excelsior, Carpinus, Abies alba and Fagus sylvatica, most likely survived the Last Glacial Maximum (LGM) at favorable sites in the Euganean Hills. The percentage values of temperate trees are comparable with those from Southern Europe (e.g. Monticchio in Southern Italy). We conclude that the Euganean Hills were one of the northernmost refugial areas of temperate taxa in Europe. However, the relative and absolute abundances of pollen of temperate trees are highly variable. Pollen-inferred declines of temperate tree communities (e.g. Quercetum mixtum) and low ostracod-inferred water levels at Lago della Costa correspond to the cold Heinrich events H-2 (LGM; 23,000–19,000 cal. BP) and H-3 (around 28,000 cal. BP), as recorded in the marine sediments of the North Atlantic. Similar patterns of significant temperate tree population collapses during cold Heinrich events are recorded at southern Mediterranean sites (e.g. Monticchio and the Alboran Sea). These findings suggest close linkages between Northern Atlantic and South-Central European climates during the past Glacial.  相似文献   

Holistic, adaptive management of the terrestrial carbon cycle at local and regional scales   总被引：2，自引：0，他引：2  

Petra Tschakert  Elisabeth Huber-Sannwald  Dennis S. Ojima  Michael R. Raupach  Erich Schienke 《Global Environmental Change》2008,18(1):128-141

Actions to manage carbon dioxide (and other greenhouse gas) emissions at regional and local scales take place amid multiple requirements, participants, and agents. To address and solve tensions that emerge from diverse objectives and stakeholder needs, participatory decision processes and information tools are required. This paper explores how regional carbon budget information can contribute to the broader goal of holistic, adaptive regional development. We sketch the characteristics of a novel integrative framework for adaptive carbon management in the context of multiple criteria. An ex-post case study on carbon mitigation from Chiapas, Mexico, demonstrates challenges and trade-offs in a real-world setting.  相似文献   

European glacial relict snails and plants: environmental context of their modern refugial occurrence in southern Siberia          下载免费PDF全文

Michal Horsák  Milan Chytrý  Petra Hájková  Michal Hájek  Jiří Danihelka  Veronika Horsáková  Nikolai Ermakov  Dmitry A. German  Martin Kočí  Pavel Lustyk  Jeffrey C. Nekola  Zdenka Preislerová  Milan Valachovič 《Boreas: An International Journal of Quaternary Research》2015,44(4):638-657

Knowledge of present‐day communities and ecosystems resembling those reconstructed from the fossil record can help improve our understanding of historical distribution patterns and species composition of past communities. Here, we use a unique data set of 570 plots explored for vascular plant and 315 for land‐snail assemblages located along a 650‐km‐long transect running across a steep climatic gradient in the Russian Altai Mountains and their foothills in southern Siberia. We analysed climatic and habitat requirements of modern populations for eight land‐snail and 16 vascular plant species that are considered characteristic of the full‐glacial environment of central Europe based on (i) fossil evidence from loess deposits (snails) or (ii) refugial patterns of their modern distributions (plants). The analysis yielded consistent predictions of the full‐glacial central European climate derived from both snail and plant populations. We found that the distribution of these 24 species was limited to the areas with mean annual temperature varying from ?6.7 to 3.4 °C (median ?2.5 °C) and with total annual precipitation varying from 137 to 593 mm (median 283 mm). In both groups there were species limited to areas with colder and drier macroclimates (e.g. snails Columella columella and Pupilla loessica, and plants Kobresia myosuroides and Krascheninnikovia ceratoides), whereas other species preferred areas with relatively warmer and/or moister macroclimates (e.g. snails Pupilla turcmenica and P. alpicola, and plants Artemisia laciniata and Carex capillaris). Analysis of climatic conditions also indicated that distributional shifts of the studied species during the Pleistocene/Holocene transition were closely related to their climatic tolerances. Our results suggest that the habitat requirements of southern Siberian populations can provide realistic insights into the reconstruction of Eurasian, especially central European, glacial environments. Data obtained from modern populations also highlight the importance of wet habitats as refugia in the generally dry full‐glacial landscape.  相似文献   

The application of electrical resistivity tomography and gravimetric survey as useful tools in an active tectonics study of the Sudetic Marginal Fault (Bohemian Massif, central Europe)     

Petra &#x;tpan íkov  Ji&#x;í Dohnal  Tom&#x; Pnek  Monika &#x;j  Veronika Smolkov  Karel &#x;ilhn 《Journal of Applied Geophysics》2011,74(1):69-80

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Impact of the deeper geological basement on soil gas and indoor radon concentrations in areas of Quaternary fluvial sediments (Bohemian Massif,Czech Republic)     

Ivan Barnet  Petra Pacherová 《Environmental Earth Sciences》2011,63(3):551-557

The relationship of soil gas radon Rn²²² and indoor radon was studied within the Quaternary fluvial sediments of the Czech Republic. The processing of data selection from the radon database of the Czech Geological Survey and indoor radon data (database of the National Radiation Protection institute) has proved the concentration dependence of radon in Quaternary fluvial sediments on deeper bedrock. The ArcGIS processing was accompanied by the field verification in five profiles, intersecting the granitoid Central Bohemian Plutonic Complex and its rim rock types. Both theoretical and experimental results show dependence of soil gas radon and indoor radon concentrations in Quaternary fluvial sediments on deeper geological basement, thus leading to the conclusion that the lateral transport of Quaternary sediments does not play such a dominant role in radon concentrations, as was thought previously. This fact will enable to determine precisely the radon index of Quaternary sediments (in the Czech radon mapping classified as an intermediate index) into three categories according to the lithology of their geological basement.  相似文献   

Space,social reproduction and food security in Cairo/Egypt     

Jörg Gertel  Petra Kuppinger 《GeoJournal》1994,34(3):277-286

Urban life is a highly interconnected historically developed web of social relations. Taking the example of Cairo, Egypt, the construction of urban space over the last 150 years is discussed, and attention is further given to more recent urban planning objectives. The paper then takes up issues of space and social reproduction and traces them down to the microlevel of individual households in order to analyse how larger changes in the food system are shaping local food security.This article is a result of an interdisciplinary research project on the Metropolitan Food System of Cairo, Egypt, untertaken by the Institute of Cultural Geography, Freiburg University, Germany, which is funded by the German Research Society (Deutsche Forschungsgemeinschaft, DFG). Petra Kuppinger is also grateful for the support offered through a Research Fellowship by the Anthropology Department at the American University in Cairo.  相似文献   

Spatial patterns and drivers of fire occurrence in a Mediterranean environment: a case study of southern Croatia     

Katarina Pavlek  Filip Bišćević  Petra Furčić  Ana Grđan  Vesna Gugić  Nino Malešić 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2017,117(1):22-35

Wildfires are an important factor of landscape dynamics in fire-prone environments of the world. In the Mediterranean, one of the most fire-susceptible environments globally, between 45,000 and 50,000 wildfires are recorded every year, causing disturbances in forest and grassland ecosystems. As a Mediterranean country, Croatia faces these problems, averaging over 1000 registered wildfires annually, with the coastal areas dominated by forest fires and continental Croatia by fires on agricultural lands. This research combines various landscape and socio-economic factors in the analysis of fire occurrence in Croatia’s southernmost region of Dalmatia. Around 275 of the largest fires (encompassing 98% of the total burnt area) registered in 2013 were investigated using OLS, and different spatial indices were employed to analyse regional variability in fire distribution. The results revealed that areas more prone to fires are the northern inland areas of Dalmatia and its entire coastal zone. Altitude and vegetation type demonstrated a correlation with fire occurrence, but an increase in population in the study area was also correlated with wildfire occurrence. Regarding vegetation, the grasslands and Mediterranean shrubland (maquis) were found to be the most fire-prone vegetation types in the study region, the distribution of which can be linked to different socio-economic and demographic processes occurring in the Eastern Adriatic.  相似文献   

An evaluation of trace metal distribution and environmental risk in sediments from the Lake Kalimanci (FYR Macedonia)     

Petra Vrhovnik  Nastja Rogan Šmuc  Tadej Dolenec  Todor Serafimovski  Matej Dolenec 《Environmental Earth Sciences》2013,70(2):761-775

Pollution from mining activities is a significant problem in several parts of the Republic of Macedonia. A geochemical study of the surficial sediments of Lake Kalimanci in the eastern part of the Republic of Macedonia was carried out to determine their elemental compositions and to evaluate the pollution status of lake sediments by employing an enrichment factor (EF). The major and trace element contamination in surficial lake sediments was studied to assess the effects of metalliferous mining activities. The mean concentrations of major elements (wt%) Si 23.5, Al 7.9, Fe 6.6, Mg 1.3, Ca 3.8, Na 1.1, K 2.3, Ti 0.4, P 0.2, Mn 0.6 and trace elements ranged within Mo 1.0–4.6 mg kg^?1, Cu 144.4–1,162 mg kg^?1, Pb 1,874–16,300 mg kg^?1, Zn 2,944–20,900 mg kg^?1, Ni 21.7–79.3 mg kg^?1, Cd 16.5–136 mg kg^?1, Sb 0.6–3.6 mg kg^?1, Bi 3.0–24,3 mg kg^?1 and Ag 1.4–17.3 mg kg^?1. The EF ranged within 0.12–590.3. Among which, Cd, Pb, Zn and As have extremely severe enrichment. The data indicate that trace elements had extremely high concentrations in Lake Kalimanci surficial sediments owing to the anthropogenic addition of contaminants.  相似文献   

Traffic-related immissions and their impact on historic buildings: implications from a pilot study at two German cities   总被引：1，自引：1，他引：0  

Michael Auras  Silvia Beer  Petra Bundschuh  Joachim Eichhorn  Martin Mach  Dirk Scheuvens  Michael Schorling  Jonas von Schumann  Rolf Snethlage  Stephan Weinbruch 《Environmental Earth Sciences》2013,69(4):1135-1147

Besides the enormous improvement of air quality in Germany due to the reduction of sulphur dioxide emissions in the last decades, high immissions of nitrogen oxides and fine particulate matter are frequently observed at traffic-rich urban sites. The changed chemical composition of air pollution requires a new investigation of its impact on historic buildings constructed of natural stone. In a pilot study a multi-disciplinary approach was chosen to obtain information on the actual pollution situation of historic buildings and monuments at traffic hotspots in Germany. The study concentrated on the two German cities of Munich and Mainz of different size, traffic volume and stone inventory. Dose–response functions were calculated to demonstrate the change of impact of different pollutants over the last three decades, and for comparison of traffic hotspots and housing areas of both cities. Numeric modelling on a city-scale was used to identify the historic buildings and monuments affected by elevated traffic immissions. Because a relevant part of these pollutants is dominated by short-range transport, the differences of wind speed and deposition rates were calculated using a street-scale 3D flow and dispersion model regarding traffic volume, wind regime and adjacent buildings. Finally, particulate matter was sampled at different positions of two buildings heavily exposed to traffic emissions. Individual particles were investigated by environmental scanning electron microscopy. After classification of the particles into different chemical groups, the fraction of traffic-induced particulate matter was quantified. Summarizing the results, it must be stated that soiling by traffic-related particulate matter, deposition of nitrates deriving from exhaust emission and other diffusely emitted components bear a severe damage potential for natural building stone at least locally at traffic-rich urban sites.  相似文献