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31.
We introduce the freely available web-based Water in an Agricultural Landscape—NUčice Database (WALNUD) dataset that includes both hydrological and meteorological records at the Nučice experimental catchment (0.53 km2), which is representative of an intensively farmed landscape in the Czech Republic. The Nučice experimental catchment was established in 2011 for the observation of rainfall–runoff processes, soil erosion processes, and water balance of a cultivated landscape. The average altitude is 401 m a.s.l., the mean land slope is 3.9%, and the climate is humid continental (mean annual temperature 7.9°C, annual precipitation 630 mm). The catchment is drained by an artificially straightened stream and consists of three fields covering over 95% of the area which are managed by two different farmers. The typical crops are winter wheat, rapeseed, and alfalfa. The installed equipment includes a standard meteorological station, several rain gauges distributed across the basin, and a flume with an H-type facing that is used to monitor stream discharge, water turbidity, and basic water quality indicators. Additionally, the groundwater level and soil water content at various depths near the stream are recorded. Recently, large-scale soil moisture monitoring efforts have been introduced with the installation of two cosmic-ray neutron sensors for soil moisture monitoring. The datasets consist of observed variables (e.g. measured precipitation, air temperature, stream discharge, and soil moisture) and are available online for public use. The cross-seasonal, open access datasets at this small-scale agricultural catchment will benefit not only hydrologists but also local farmers.  相似文献   
32.
In Arctic alpine regions, glacio‐lacustrine environments respond sensitively to variations in climate conditions, impacting, for example,glacier extent and rendering former ice‐contact lakes into ice distal lakes and vice versa. Lakefloors may hold morphological records of past glacier extent, but remoteness and long periods of ice cover on such lakes make acquisition of high‐resolution bathymetric datasets challenging. Lake Tarfala and Kebnepakte Glacier, located in the Kebnekaise mountains, northern Sweden, comprise a small, dynamic glacio‐lacustrine system holding a climate archive that is not well studied. Using an autonomous surface vessel, a high‐resolution bathymetric dataset for Lake Tarfala was acquired in 2016, from which previously undiscovered end moraines and a potential grounding line feature were identified. For Kebnepakte Glacier, structure‐from‐motion photogrammetry was used to reconstruct its shape from photographs taken in 1910 and 1945. Combining these methods connects the glacial landform record identified at the lakefloor with the centennial‐scale dynamic behaviour of Kebnepakte Glacier. During its maximum 20th century extent, attained c. 1910, Kebnepakte Glacier reached far into Lake Tarfala, but had retreated onto land by 1945, at an average of 7.9 m year–1. Copyright © 2019 John Wiley & Sons, Ltd.  相似文献   
33.
Mountain-top observations of greenhouse gas mixing ratios may be an alternative to tall-tower measurements for regional scale source and sink estimation. To investigate the equivalence or limitations of a mountain-top site as compared to a tall-tower site, we used the unique opportunity of comparing in situ measurements of methane (\(\hbox {CH}_{4}\)) and carbon dioxide (\(\hbox {CO}_{2}\)) mixing ratios at a mountain top (986 m above sea level, a.s.l.) with measurements from a nearby (distance 28.4 km) tall tower, sampled at almost the same elevation (1009 m a.s.l.). Special attention was given to, (i) how local wind statistics and greenhouse gas sources and sinks at the mountain top influence the observations, and (ii) whether mountain-top observations can be used as for those from a tall tower for constraining regional greenhouse gas emissions. Wind statistics at the mountain-top site are clearly more influenced by local flow systems than those at the tall-tower site. Differences in temporal patterns of the greenhouse gas mixing ratios observed at the two sites are mostly related to the influence of local sources and sinks at the mountain-top site. Major influences of local sources can be removed by applying a statistical filter (\(5{\mathrm{th}}\) percentile) or a filter that removes periods with unfavourable flow conditions. In the best case, the bias in mixing ratios between the mountain-top and the tall-tower sites after the application of the wind filter was \({-}0.0005\pm 0.0010\) ppm for methane (September, 0000–0400 UTC) and \(0.11\pm 0.18\) ppm for \(\hbox {CO}_{2}\) (February, 1200–1600 UTC). Temporal fluctuations of atmospheric \(\hbox {CH}_{4}\) and \(\hbox {CO}_{2}\) mixing ratios at both stations also showed good agreement (apart from \(\hbox {CO}_{2}\) during summertime) as determined by moving bi-weekly Pearson correlation coefficients (up to 0.96 for \(\hbox {CO}_{2}\) and 0.97 for \(\hbox {CH}_{4}\)). When only comparing mixing ratios minimally influenced by local sources (low bias and high correlation coefficients), our measurements indicate that mountain-top observations are comparable to tall-tower observations.  相似文献   
34.
微微型浮游植物是水环境生态碳汇的重要基石之一,也是初级生产的重要执行者。选取了一个典型的陆海交界关键带环境——海南东寨港入海口水域,采集了东寨港红树林保护区开阔水域、入港河流和新埠海海端的微微型浮游植物的样品,通过流式细胞仪分析技术对样品进行分析,以探究它们在东寨港水域中的丰度、分布及环境指示意义。结果表明,冬季水域微微型浮游植物以真核浮游植物(Eukaryote,Euk)和聚球藻(Synechococcus,Syn)两大类群为主,其中聚球藻有两个亚群,分别为富含藻蓝蛋白聚球藻(Phycocyanin-rich,PC)和富含藻红蛋白聚球藻(Phycoerythrin-rich,PE)。Syn-PC、Syn-PE和Euk在东寨港水域表层水体的平均丰度分别为(2.61×104±1.09×104)、(3.06×104±7.05×103)、(1.56×105±8.03×104) cells/m L,底层水体的平均丰度分别为(2.64×104±...  相似文献   
35.
Baron  Nina 《Natural Hazards》2020,103(1):967-984
Natural Hazards - As a result of still more flood events in Denmark in the last few years, flood protection has received growing attention in many local communities. By law, in Denmark, protecting...  相似文献   
36.
Organisms have evolved a cellular response called stress protein response that increases their tolerance in adverse environmental conditions. Well known stress proteins that bind essential and toxic metals are metallothionein (MT). The scallop Mizuhopecten yessoensis is the most interesting organism because it is able to accumulate toxic cadmium in its digestive gland. However, in the tissue of the digestive gland of Mizuhopecten yessoensis MT (metallothioneins) have not been found. Eastern scallops, Mizuhopecten yessoensis, were collected from two locations ?? one clean and one polluted site. The concentrations of cadmium (Cd), copper (Cu) and zinc (Zn) were measured in the digestive gland. There was a significant increase in Cd concentrations in this studied tissue. We found that in the presence of cadmium Mizuhopecten yessoensis can induce high molecular proteins. The results of experiments have shown that Cd-binding ligands have a number of properties similar to MT: acetone and temperature stability; the ability to bind some metals, including Cd, Cu and Zn. Protein chromatography (FPLC, Superosa 12) from the digestive gland of scallop M. yessoensis has shown that cadmium is associated with high molecular weight Cd-binding proteins (72 kDa and 43 kDa). The major cadmium-binding protein 72 kDa is glycoprotein. In experiments we have demonstrated that Cd-binding proteins can be induced when there is cadmium exposure. The results of this study strongly suggest that the far eastern scallop Mizuhopecten yessoensis has a unique and well-developed system for the detoxification of heavy metals and it allows for biochemical systems to be maintained in a relatively stable manner in the presence of heavy metals.  相似文献   
37.
A dual foraging strategy (long versus short trips) has been described for some species of seabirds, such as petrels, albatrosses (Procellariiformes) and penguins (Sphenisciphormes). Such a strategy has recently been reported for little auks ( Alle alle ) from the central coast of west Spitsbergen, Svalbard. This has been explained as a response to poor trophic conditions close to the breeding colony, and better conditions further away (150 km). In the present study, we investigated the foraging strategy of little auks in Hornsund, southern Spitsbergen, during two seasons with contrasting oceanographic conditions. During 2004, foraging conditions for little auks were good: cold Arctic waters rich in profitable high-energy food were dominant in their feeding grounds. Conversely, during 2006 there was a great influx of warm Atlantic water in the feeding area, inducing poor foraging conditions. In both seasons we examined the pattern of foraging trip lengths automatically with a video camera (both adults from four nests in each year), and by direct non-stop observation of 20–54 individually marked birds. Our results showed that the dual strategy and the ratio of short and long trips were consistent, regardless of the conditions in the feeding grounds. This suggests that the strategy is inherent and may be crucial for the self-maintenance of adults.  相似文献   
38.
西藏西部台错湖T1阶地的两个剖面沉积中,除下部10余厘米含炭化植物和50~70 cm处为暗色碳酸盐粘土及粘土外,中、上部全系粘土碳酸盐层,含丰富的介形类和轮藻类.据碳酸盐、介形类、轮藻类的碳、氧稳定同位素值与微体古生物群落生态特征等提供的环境气候变化指标,指示该区距今41.4~4.5 ka BP间气候变化为:在41.4~26.2 ka BP气候较湿润;26.2~25.5 ka BP偏暖稍干;25.5~22.5 ka BP气候暖湿;22.5~21.0 ka BP气候偏冷湿;20.5~17.5 ka BP气候骤冷、偏湿,反映本区处于末次冰期盛冰期;17.5~16.0 kaBP偏冷偏干;16.0~11.8 ka BP气候偏暖湿,为全球间歇性暖事件的响应;11.8~10.4 ka BP气候较冷干,大致相当于新仙女木期,10.4 ka BP气温开始回升;10.4~9.4 ka BP气候偏暖湿;9.4~8.5 ka BP气候呈现短暂暖湿颤动;8.5~7.9 ka BP气候偏干冷,为冰后期强烈降温偏干事件;7.8~6.3 ka BP气候偏暖湿;6.3~4.5 ka BP气候趋向冷干,4.5 ka BP记录了晚更新世晚期以来最大的干燥期.  相似文献   
39.
Based on a set of very long-living (2,000?years) Qilian junipers (Sabina przewalskii Kom.) from the north-eastern part of the Tibetan Plateau (the region of Dulan), we carefully consider the regional curve standardization (RCS) technique. For this goal, we correlate deviations of individual tree-ring width records from their regional mean age-dependent curve (RC). It turns out that these correlations keep their positivity for almost all shifts between ages compared (up to 500?years and even more) evidencing each Dulan juniper to be a unique ??thermometer??. Just the unification of these ??thermometers?? in the form RC creates a spurious positive trend in the Dulan chronology. We modify the RCS technique to closer attach RC to these ??thermometers?? in order to construct a new chronology in which the trend is absent.  相似文献   
40.
Two sedimentary sections were measured at Tai Co (Co means lake in Tibetan) in western Tibet, China. The two sections are almost all composed of clay carbonate beds except in their lower parts where there are carbonized plants at >10 cm depths and dark-colored carbonate clay and clay at 50–70 cm depths, yielding abundant gastropods, ostracods, and charophytes. The carbon and oxygen stable isotope values of carbonate, ostracods, and charophytes and ecological features of microfossil communities indicate the following climatic change in the area from 41.4 to 4.5 ka BP: at 41.4–26.2 ka BP, the climate was relatively wet; at 26.2–25.5 ka BP, it was slightly warm-dry; at 25.5–22.5 ka BP, it was warm-wet; at 22.5–21.0 ka BP, it was slightly cold-wet; at 20.5–17.5 ka BP, it became cold abruptly and slightly wet, implying the climate of the last glacial maximum; at 17.5–16.0 ka BP, it was slightly cold-dry; at 16.0–11.8 ka BP, it was slightly warm-wet; at 11.8–10.4 ka BP, it was relatively cold-dry, roughly equivalent to the climate of the Younger Dryas, and at 10.4 ka BP, the temperatures began to rise again; at 10.4–9.4 ka BP, it was slightly warm-wet; at 9.4–8.5 ka BP, there occurred short warm-wet oscillations; at 8.5–7.9 ka BP, it was slightly dry-cold, representing a strong temperature-lowering and drying event in the postglacial stage; at 7.8–6.3 ka BP, it was slightly warm-wet; at 6.3–4.5 ka BP, the climate tended to be cold-dry. 4.5 ka BP recorded the maximum aridity since the late part of the late Pleistocene.  相似文献   
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