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61.
Seasonal dependency of controlling factors on the phytoplankton production in Taihu Lake, China 总被引:1,自引:0,他引:1
In this study, 44 profiles of gross primary productivity(GPP) and sunlight, along with water temperature, Chlorophyll-a(Chla) and nutrients, were observed in Meiliang Bay of Taihu Lake, China, in the spring, summer, and fall seasons. Effects of water temperature, light,and nutrient concentration were examined in relation to the GPP-unit-Chla(GPP of algae per Chla). The results showed that the optimum temperature for the GPP of phytoplankton was 27.9°C, the optimal PNA-unit-Chla(photon number absorbed by phytoplankton per Chla) was 0.25(mol), and the HSCN-unit-Chla and HSCP-unit-Chla(half-saturation constants of nitrogen and phosphorus of algae per Chla) were 0.005(mg/L) and 0.0004(mg/L), respectively. The seasonal dependency of the effect of different factors on the GPP was analyzed. Compared with temperature and nutrients, light was found to be the most important factor affecting the GPP during the three seasons. The effect of temperature and nutrients on the GPP of phytoplankton has obvious seasonal change. In spring, temperature was the secondary factor affecting the GPP of phytoplankton, and the effect of nutrients may be negligible in the eutrophic lake on account of temperature limit, which showed that the GPP of algae was only affected by the physical process. In summer and fall, temperature didn't affect the GPP of algae, and the presence of nutrients was the secondary factor affecting the GPP of phytoplankton. From summer to fall, effect of phosphorus was weakened and effect of nitrogen was enhanced. 相似文献
62.
We argue that attempts to extrapolate moral motives for non‐egoistic behavior in organizational behavior often interpret results empathically or deontically, while leaving other moral motivational frames, such as the utilitarian and virtue ethical, under‐examined. We encourage the creation of experimental measures to distinguish various philosophical frames. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
63.
This paper examines the role of community-based management (CBM) in dealing with the problem of mine water pollution (MWP) in four ex-pit sites in northeast England. The outcomes of CBM can be divided into two categories: ecological (environmental improvement) and social (community improvement). The ecological outcomes range from problem recognition to investigation and remediation; the social outcomes range from community awareness to participation and enhanced cooperation. Both kinds of outcome were completely achieved in only one site (Quaking Houses). In the other three sites, varying degrees of success were achieved in each category. The main lessons learned are two-fold: first, even if CBM does not achieve its ecological aims, it may nonetheless be valuable in achieving social outcomes; second, its chances of achieving either ecological or social outcomes are linked to the resources (human, technical, financial, experiential, structural, legitimacy and network) that the community possesses. 相似文献
64.
We report on a fetus presenting with increased nuchal translucency at 11 weeks' gestation, suggesting cystic hygroma. Chorion villous sampling was performed, and cytogenetic analysis revealed a supernumerary isochromosome 5p leading to tetrasomy 5p: 47,XX,+ i(5p)[7]/46,XX[5] after short-term culture and 47,XX,+ i(5p)[20] after long-term culture. Subsequent targeted sonographic follow-up at 12 and 14 weeks revealed further increase of the NT to 6.4 mm and the additional presence of a congenital heart defect (pulmonary atresia with intact ventricular septum). Termination of pregnancy was performed, and the heart defect was confirmed. Isochromosome 5p was found in varying proportions in all examined organs. Only a few cases of mosaic tetrasomy 5p have been reported in the literature, and recent reports on prenatally detected isochromosome 5p showed a possible relationship to increased nuchal translucency in some cases and also a possible role of confined mosaicism in others. Whereas cases with confined mosaicism did not show suspicious signs on ultrasound, true mosaicism conversely showed increased nuchal thickness as well as structural abnormalities. This is the first report on the association of a cardiac defect with this chromosome aberration. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
65.
66.
Hong Yang Xianjin Huang Jianlin Hu Julian R. Thompson Roger J. Flower 《Frontiers of Environmental Science & Engineering》2022,16(8):111
China has been committed to achieving carbon neutrality by 2060. China’s pledge of carbon neutrality will play an essential role in galvanising global climate action, which has been largely deferred by the Covid-19 pandemic. China’s carbon neutrality could reduce global warming by approximately 0.2–0.3 °C and save around 1.8 million people from premature death due to air pollution. Along with domestic benefits, China’s pledge of carbon neutrality is a “game-changer” for global climate action and can inspire other large carbon emitters to contribute actively to mitigate carbon emissions, particularly countries along the Belt and Road Initiative (BRI) routes. In order to achieve carbon neutrality by 2060, it is necessary to decarbonise all sectors in China, including energy, industry, transportation, construction, and agriculture. However, this transition will be very challenging, because major technological breakthroughs and large-scale investments are required. Strong policies and implementation plans are essential, including sustainable demand, decarbonizing electricity, electrification, fuel switching, and negative emissions. In particular, if China can peak carbon emissions earlier, it can lower the costs of the carbon neutral transition and make it easier to do so over a longer time horizon. China’s pledge of carbon neutrality by 2060 and recent pledges at the 26th UN Climate Change Conference of the Parties (COP26) are significant contributions and critical steps for global climate action. However, countries worldwide need to achieve carbon neutrality to keep the global temperature from growing beyond the level that will cause catastrophic damages globally. 相似文献
67.
Catalina Munteanu Cornelius Senf Mihai D. Nita Francesco Maria Sabatini Julian Oeser Rupert Seidl Tobias Kuemmerle 《Conservation biology》2022,36(2):e13820
High-conservation-value forests (HCVFs) are critically important for biodiversity and ecosystem service provisioning, but they face many threats. Where systematic HCVF inventories are missing, such as in parts of Eastern Europe, these forests remain largely unacknowledged and therefore often unprotected. We devised a novel, transferable approach for detecting HCVFs based on integrating historical spy satellite images, contemporary remote sensing data (Landsat), and information on current potential anthropogenic pressures (e.g., road infrastructure, population density, demand for fire wood, terrain). We applied the method to the Romanian Carpathians, for which we mapped forest continuity (1955–2019), canopy structural complexity, and anthropogenic pressures. We identified 738,000 ha of HCVF. More than half of this area was identified as susceptible to current anthropogenic pressures and lacked formal protection. By providing a framework for broad-scale HCVF monitoring, our approach facilitates integration of HCVF into forest conservation and management. This is urgently needed to achieve the goals of the European Union's Biodiversity Strategy to maintain valuable forest ecosystems. 相似文献
68.
Andreas Schierling Karlheinz Seifert Sebastian R. Sinterhauf Julian B. Rieß Johanna C. Rupprecht Konrad Dettner 《Chemoecology》2013,23(1):45-57
The pygidial gland secretion of the rove beetle genera Stenus Latreille and Dianous Leach is composed of pyridine and piperidine-derived alkaloids and several terpene compounds. Two-choice bioassays with ants and fish, as well as agar diffusion assays, revealed that the secretion compounds are capable of deterring predators and protecting the beetles from infestation with microorganisms. In addition, the beetles use the secretion for rapid movements on the water surface, a process called skimming. Thus, originally developed to chemically defend the sensitive unprotected abdomen from predator attacks, the secretion of recent Steninae can be designated as multifunctional. Four of the alkaloid compounds occur as different configurational isomers in the secretion. Two-choice tests showed that ants discriminate between stereoisomers of stenusine, while there was no effect visible on bacteria in agar diffusion assays. Furthermore, there are evolutionary trends within the Steninae concerning the secretion composition, as some of the alkaloids primarily occur in phylogenetically basal species, while others are mainly restricted to derived species. 相似文献
69.
Because of the expanding population in our cities with its demands for more diversified services, we cannot afford a piecemeal type of urban underground growth. Utilization of the urban street system for buried utilities has a serious adverse effect on other street functions because of the continuing necessity to perform excavations for the repair of existing lines and the installation of new ones. The excavations not only are a serious cause of traffic delay and congestion but also create noise and aesthetic disturbances, and result in excessive street maintenance requirements and in shortened overall street life. Consider the enhancing effects in quietness on abutting properties and users of the street, and the benefits become very great. Unfortunately, the lack of data and the difficulty in quantifying the intangibles have made it impossible to arrive at a reasonably accurate figure of overall negative impact on the urban environment of street cuts. However, if drivers are sufficiently strong to merit the use of utility tunnels, then sustainable municipal policies improving living quality will be implemented. 相似文献
70.
The hydrologic regime is regarded as the primary driver of freshwater ecosystems, structuring the physical habitat template, providing connectivity, framing biotic interactions, and ultimately selecting for specific life histories of aquatic organisms. In the present study, we tested ecological theory predicting directional relationships between major dimensions of the flow regime and life history composition of fish assemblages in perennial free-flowing rivers throughout the continental United States. Using long-term discharge records and fish trait and survey data for 109 stream locations, we found that 11 out of 18 relationships (61%) tested between the three life history strategies (opportunistic, periodic, and equilibrium) and six hydrologic metrics (two each describing flow variability, predictability, and seasonality) were statistically significant (P < or = 0.05) according to quantile regression. Our results largely support a priori hypotheses of relationships between specific flow indices and relative prevalence of fish life history strategies, with 82% of all significant relationships observed supporting predictions from life history theory. Specifically, we found that (1) opportunistic strategists were positively related to measures of flow variability and negatively related to predictability and seasonality, (2) periodic strategists were positively related to high flow seasonality and negatively related to variability, and (3) the equilibrium strategists were negatively related to flow variability and positively related to predictability. Our study provides important empirical evidence illustrating the value of using life history theory to understand both the patterns and processes by which fish assemblage structure is shaped by adaptation to natural regimes of variability, predictability, and seasonality of critical flow events over broad biogeographic scales. 相似文献