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During the period August 1981 to July 1982, samples of six species of Amphipoda common to Hornsund were collected, and a study of their energy value changes was carried out. Only slight fluctuations of energy values were observed throughout the year, and no distinct seasonal changes as in the case of boreal organisms. Individuals of greater body size exhibit higher energy values. The lowest energy values 10.93 kJ g−1 d.w. (SD = 3.01) and highest ash contents 29.8% (SD = 7.6) were found in small Amphipoda (e.g. Ischyrocerus anguipes) , while species attaining greater body size were characterized by higher energy values and lower ash contents, for example Gammarellus homari 16.96 kJ g−1 d.w. (SD = 0.50), and 22.9% (SD = 3.3%) ash. 相似文献
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PIOTR JAN ANGIEL MACIEJ DĄBSKI 《Geografiska Annaler: Series A, Physical Geography》2012,94(3):395-412
The recently observed recession of glaciers on King George Island is associated with decades of climate warming in the Antarctic Peninsula region. However, with only 60 years of glaciological observations in the study area ages of the oldest moraines are still uncertain. The goal of the study was to estimate ages of lichen colonization on the oldest moraines of the Ecology and White Eagle Glaciers on King George Island and on the Principal Cone of Penguin Island volcano. The first lichenometric studies on these islands from the late 1970s used rates that had about four to five times slower Rhizocarpon growth rates. We re‐examined the sites and measured 996 thalli diameters to establish the surface ages. To estimate the age we used (1) long‐term Rhizocarpon lichen group growth rates established by authors using data from a previous lichenometric study on King George Island, and (2) previous data of lichen growth rates from other sub‐Antarctic islands. Our results suggest growth rates between 0.5 and 0.8 mm yr–1. According to these rates the ages of the oldest moraine ridges are of the Little Ice Age and were colonized at the beginning of the twentieth century. The mid‐twentieth century age of lichen colonization on the historically active Penguin Island volcano might support the date of the last eruption reported by whalers in the end of the nineteenth and the beginning of the twentieth century. 相似文献
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Abstract Detection of nonstationarity in series of flow records is of vast scientific and practical significance. In order to develop guidance as to the choice of an appropriate test, among the many candidates, one has recourse to analysis of a controlled trend artificially introduced to generated data mimicking river flow observations. Raw series of good quality flow data were normalized and de-seasonalized and subsequently transformed to the Fourier spectral domain. Keeping the power spectrum preserved, the phase spectrum was subjected to randomization. After transformation back to the temporal domain, the data were contaminated with trends and step changes in a controlled way. The results evaluate the detectability of nonstationarity by particular tests as a quasi-continuous function of magnitude of the contaminating change. A method is devised to compare the tests' performance, with the objective of choosing an appropriate tool. Analysis of detectability versus change magnitude gives a new insight, of direct practical applicability, into the properties of the tests. Further insight is provided by examining over 200 real series of river flow records. 相似文献
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MACIEJ ZALEWSKI 《水文科学杂志》2013,58(5):823-832
Abstract The increasing human population and degradation of biological integrity of ecosystems has been expressed, to a great extent, as a decline in water resources, the most critical factor to achieve sustainable development. This is because overexploitation and degradation of the biotic structure alters ecosystem processes to the point at which the ecosystem ability to provide desired resources is seriously diminished. The progress in ecology during recent years has created a background for integration of ecology and hydrology. UNESCO, under the International Hydrological Programme IHP-V, has initiated and provided a framework for such an interdisciplinary effort. During the programme, the conceptual background and principles of the surficial processes of ecohydrology were defined: first, by integration and quantification of biological and hydrological processes at the basin scale; second, by the enhancement of basin ecosystem absorbing capacity against human impact; and third, by using ecosystem properties as a management tool. Those principles are targeted, not only to eliminate threats, but also to amplify the opportunities for sustainable development as far as the control and regulation of nutrients and water cycling at the basin scale become possible. According to Popper's philosophy, the predictive planning of the future cannot be generated by extrapolating from recently used solutions. The integration of environmental sciences should create not only new scientific disciplines, but also a new solution which can face new challenges-sustainable management of the biogeosphere. 相似文献
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Calorific value, lipid content and radioactivity of common species from Hornsund, Southwest Spitsbergen 总被引：1，自引：0，他引：1
In the summer of 1981 the common flora and fauna of 28 species from Hornsund were collected, and the energy value, lipid content and global activity determined. It was found that the plants had low energy values, varying from 12.26 ± 0.42 kJ g−1 dry weight to 15.45 ±1.00kJ'dry weight. The highest values in animals were noted in Liparis liparis (Pisces) 22.15 ± 0.89 kJg−1 dry weight, and Sagitta elegans (Chae-tognatha) 20.64 ± 0.49kJg−1 , the lowest being in Orchomene minuta (Amphipoda) 11.30 ± 0.74kJg−1 d.w. The lipid contents in the species studied were mostly low, the mean range from lowest to highest being 1.37-8.60% for plants and 7.14–31.93% for animals, and they were proportional to the energy value. Both the energy values and lipid contents were comparable to those in similar species from other waters. The global fi activity in the organisms analysed was not high; at the same time plants had a higher content of radioactive isotopes, 1.97-61.9pCi g−1 d.w., than animals, 5.2-17.8pCi g−1 d.w. 相似文献
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