Alterations of the Nitrogen Mineralization Rates in Soils of Forest Community Depending on the Ski Run Construction (Mount Uludag,Bursa,Turkey)     

Gürcan GLERYZ  Serap KIRMIZI  Hülya ARSLAN  Ece KONDU YAKUT 《山地科学学报》2011,(1)

Since 1940s,Mount Uludag(Bithynian Olympus) has been considered famous with winter sports center in Turkey.In addition,it is one of the rare places because of its plant diversity and is also one of the important plant areas of Turkey.The ski run constructions are rapidly increased in the past decades in the alpine and subalpine belts of the mountain.Rate of nitrogen mineralization and some properties of soil were investigated in the soils of the three ski runs and undisturbed neighborhood forest sites.These...  相似文献   

Photosynthetic response to different light intensities, water status and leaf age of two Berberis species (Berberidaceae) of Patagonian steppe, Argentina     

P.L. Peri  M. ArenaG. Martínez Pastur  M.V. Lencinas 《Journal of Arid Environments》2011,75(11):1218-1222

Net photosynthetic rate (A) and stomatal conductance (gs) from leaves of Berberis buxifolia and Berberis heterophylla saplings were measured under different conditions of radiation and water availability and for leaves of different ages. Comparative studies of basic physiological performance would give insight how these shrubs survive and grow under this austral extreme ecosystem. B. buxifolia had higher A values than B. heterophylla for all light intensities measured. Values of gs for both Berberis species also declined as light intensity decreased. There was a negative relationship between A and water stress expressed as pre-dawn leaf water potential (ψ_lp) where the reduction in gs was the main factor that reduced A in both species. Also, A and gs of Berberis plants increased rapidly during the first days after leaf unfolding, reached a maximum value when the leaf was completely expanded, and then declined. These results could be used to estimate the responses of saplings to environmental conditions under the dynamic of natural stands in this austral extreme ecosystem and for restoration plans.  相似文献   

Characteristics of the main inorganic nitrogen accumulation in surface water and groundwater of wetland succession zones     

ZHOU Nian-qing  LI Tian-shui  ZHAO Shan  XIA Xue-min 《地下水科学与工程》2014,7(2):173-181

Based on the observation of a complete hydrological year from June 2014 to May 2015, the temporal and spatial variations of the main inorganic nitrogen (MIN, referring to NO3--N, NO2--N, NH4+-N) in surface water and groundwater of the Li River and the Yuan River wetland succession zones are analyzed. The Li River and the Yuan River are located in agricultural and non-agricultural areas, and this study focus on the influence of surface water level and groundwater depth and precipitation on nitrogen pollution. The results show that NO3--N in surface water accounts for 70%-90% of MIN, but it does not exceed the limit of national drinking water surface water standard. Groundwater is seriously polluted by NH4+-N. Based on the groundwater quality standard of NH4+-N, the groundwater quality in the Li River exceeds Class III water standard throughout the year, and the exceeding months’ proportion of Yuan River reaches 58.3%. Compared with the Yuan River, MIN in groundwater of the Li River shows significant temporal and spatial variations owing to the influence of agricultural fertilization. The correlation between the concentrations of MIN and surface water level is poor, while the fitting effect of quadratic correlation between NH4+-N concentration and groundwater depth is the best (R2=0.9384), NO3--N is the next (R2=0.5128), NO2--N is the worst (R2=0.2798). The equation of meteoric water line is δD =7.83δ18O+12.21, indicating that both surface water and groundwater come from atmospheric precipitation. Surface infiltration is the main cause of groundwater NH4+-N pollution. Rainfall infiltration in non-fertilization seasons reduces groundwater nitrogen pollution, while rainfall leaching farming and fertilization aggravate groundwater nitrogen pollution.  相似文献   

粤港澳大湾区典型城镇化地区河流氮素的时空分布特征及源解析     

黎曼姿  朱爱萍  王莹  陈建耀  梁作兵  伍祺瑞  田帝  曾港  赵良杰 《热带地理》2022,42(2):318-327

选取粤港澳大湾区典型城镇化地区广州市的流溪河—西航道—前航道为研究对象,分别于2020年7月和2021年1月开展野外调研采样活动,收集40个地表水水样样品,通过室内分析,利用水化学和同位素（δ¹⁵N-\mathrm{N}{\mathrm{O}}_{\mathrm{3}}^{-}、δ¹⁸O-\mathrm{N}{\mathrm{O}}_{\mathrm{3}}^{-}和δ¹⁵N-\mathrm{N}{\mathrm{H}}_{\mathrm{4}}^{+}）等指标,探讨研究区河流氮素的时空分布特征及其来源,研究城市化对河流氮素的影响。结果表明：从上游到下游,人类活动对Cl^-、\mathrm{N}{\mathrm{H}}_{\mathrm{4}}^{+}-N、\mathrm{N}{\mathrm{O}}_{\mathrm{3}}^{-}-N、DIN（溶解态无机氮）的质量浓度影响逐渐突显;丰水期\mathrm{N}{\mathrm{H}}_{\mathrm{4}}^{+}-N、DIN较枯水期高,主要归因于外源输入的影响强于降雨量与上游来水稀释的综合作用;在溶解态总氮的组成分布上,\mathrm{N}{\mathrm{H}}_{\mathrm{4}}^{+}-N与\mathrm{N}{\mathrm{O}}_{\mathrm{3}}^{-}-N分别是丰水期、枯水期的主要存在形态,说明丰水期人类活动影响十分显著。丰水期\mathrm{N}{\mathrm{H}}_{\mathrm{4}}^{+}-N与Cl^-的质量浓度具有较强的正相关关系,说明丰水期\mathrm{N}{\mathrm{H}}_{\mathrm{4}}^{+}-N与Cl^-可能具有相近或相同的来源。离子比值及稳定同位素的溯源结果具有较高的一致性,均显示上游农田化肥、土壤有机氮、养殖污水为上游河道的主要氮来源,而土壤有机氮、城市污水则为下游河道氮的主要来源。  相似文献   

Effect of groundwater on the ecological water environment of typical inland lakes in the Inner Mongolian Plateau          下载免费PDF全文

Chu Yu  Li-jie Wu  Yi-long Zhang  Xiu-ya Wang  Zhan-chuan Wang  Zhou Zhang 《地下水科学与工程》2022,10(4):353-366

To explore the causes of the ecological environment deterioration of lakes in the Inner Mongolia Plateau, this study took a typical inland lake Daihai as an example, and investigated the groundwater recharge in the process of lake shrinkage and eutrophication. Using the radon isotope (²²²Rn) as the main means of investigation, the ²²²Rn mass balance equation was established to evaluate the groundwater recharge in Daihai. The spatial variability of ²²²Rn activity in lake water and groundwater, the contribution of groundwater recharge to lake water balance and its effect on nitrogen and phosphorus pollution in lake water were discussed. The analysis showed that, mainly controlled by the fault structure, the activity of ²²²Rn in groundwater north and south of Daihai is higher than that in the east and west, and the difference in lithology and hydraulic gradient may also be the influencing factors of this phenomenon. The ²²²Rn activity of the middle and southeast of the underlying lake is greater, indicating that the ²²²Rn flux of groundwater inflow is higher, and the runoff intensity is greater, which is the main groundwater recharge area for the lake. The estimated groundwater recharge in 2021 was 3 017×10⁴ m³, which was 57% of the total recharge to the lake, or 1.6 times and 8.1 times that of precipitation and surface runoff. The TN and TP contents in Daihai have been rising continuously, and the average TN and TP concentrations in the lake water in 2021 were 4.21 mg·L^?1 and 0.12 mg·L^?1, respectively. The TN and TP contents entering the lake with groundwater recharge were 6.8 times and 8.7 times above those of runoff, accounting for 87% and 90% of the total input, respectively. The calculation results showed that groundwater is not only the main source of recharge for Daihai, but also the main source of exogenous nutrients. In recent years, the pressurized exploitation of groundwater in the basin is beneficial in increasing the groundwater recharge to the lake, reducing the water balance difference of the lake, and slowing down the shrinking degree of the lake surface. However, under the action of high evaporation, nitrogen and phosphorus brought by groundwater recharge would become more concentrated in the lake, leading to a continuous increase in the content of nutrients and degree of eutrophication. Therefore, the impact of changes in regional groundwater quantity and quality on Daihai is an important issue that needs further assessment.  相似文献   

Enrichment of nitrogen and 13C of methane in natural gases from the Khuff Formation,Saudi Arabia,caused by thermochemical sulfate reduction     

《Organic Geochemistry》2015

Permian Khuff reservoirs along the east coast of Saudi Arabia and in the Arabian Gulf produce dry sour gas with highly variable nitrogen concentrations. Rough correlations between N₂/CH₄, CO₂/CH₄ and H₂S/CH₄ suggest that non-hydrocarbon gas abundances are controlled by thermochemical sulfate reduction (TSR). In Khuff gases judged to be unaltered by TSR, methane δ¹³C generally falls between −40‰ and −35‰ VPDB and carbon dioxide δ¹³C between −3‰ and 0‰ VPDB. As H₂S/CH₄ increases, methane δ¹³C increases to as much as −3‰ and carbon dioxide δ¹³C decreases to as little as −28‰. These changes are interpreted to reflect the oxidation of methane to carbon dioxide.Khuff reservoir temperatures, which locally exceed 150 °C, appear high enough to drive the reduction of sulfate by methane. Anhydrite is abundant in the Khuff and fine grained nodules are commonly rimmed with secondary calcite cement. Some cores contain abundant pyrite, sphalerite and galena. Assuming that nitrogen is inert, loss of methane by TSR should increase N₂/CH₄ of the residual gas and leave δ¹⁵N unaltered. δ¹⁵N of Paleozoic gases in Saudi Arabia varies from −7‰ to 1‰ vs. air and supports the TSR hypothesis. N₂/CH₄ in gases from stacked Khuff reservoirs varies by a factor of 19 yet the variation in δ¹⁵N (0.3–0.5‰) is trivial.Because the relative abundance of hydrogen sulfide is not a fully reliable extent of reaction parameter, we have attempted to assess the extent of TSR using plots of methane δ¹³C versus log(N₂/CH₄). Observed variations in these parameters can be fitted using simple Rayleigh models with kinetic carbon isotope fractionation factors between 0.98 and 0.99. We calculate that TSR may have destroyed more than 90% of the original methane charge in the most extreme instance. The possibility that methane may be completely destroyed by TSR has important implications for deep gas exploration and the origin of gases rich in nitrogen as well as hydrogen sulfide.  相似文献   

Biochar application reduces protein sorption in soil     

《Organic Geochemistry》2015

The application of biochar (BC) as a soil amendment is of growing interest. BC has recently been shown to decelerate the cycling of soil organic N, and adsorption of proteins to BC surfaces has been put forward as an explanation. However, the effect of BC on the sorption of proteins in soil is largely unknown. The main objective of this study was therefore to test the sorption of a model protein (bovine serum albumin, BSA) on a soil amended with different types of BC. Contrary to our assumption, BC application reduced the sorption of BSA. The BC feedstock type and pyrolysis temperature affected BSA sorption; however, the underlying mechanisms require further investigation. BC-induced liming had no effect on BSA sorption, while BC’s hydrophobicity and surface area seemed to be important factors.  相似文献   

Evaluation of redox versus thermal maturity controls on δ15N in organic rich shales: A case study of the Woodford Shale,Anadarko Basin,Oklahoma, USA     

《Organic Geochemistry》2015

Bulk sedimentary nitrogen isotopes (δ¹⁵N_bulk) have been primarily used to identify bottom water redox states during deposition in sedimentary environments that have not undergone significant diagenetic or catagenetic alteration. Recently, the utility of sedimentary δ¹⁵N_bulk as a paleoredox proxy in hydrocarbon-bearing shale intervals was demonstrated by qualitatively correlating the δ¹⁵N_bulk profiles from shale units to their depositional redox conditions. However, the effect of thermal maturity on the δ¹⁵N_bulk signal remains unknown. We analyzed samples from three cores from the Devonian–Mississippian age Woodford Shale in the Anadarko Basin with vitrinite reflectance values ranging from the oil window to the gas window in order to investigate how depositional redox conditions and thermal maturation affect the bulk sedimentary δ¹⁵N signals. Our results indicate that the δ¹⁵N_bulk values for the Woodford do not correlate with thermal maturity. Instead, the δ¹⁵N_bulk values primarily reflect the depositional redox conditions, which are supported by trace metal concentrations and depositional features such as burrow abundance and lamination. The expected relationship between δ¹⁵N_bulk and paleoredox conditions was observed both within each core and between cores on a basin wide scale, with samples deposited under suboxic bottom water conditions having higher δ¹⁵N_bulk values than those deposited under anoxic bottom water conditions. Our data also indicate that redox bottom water column conditions in the Anadarko Basin varied spatially and temporally during the deposition of the Woodford Shale.  相似文献   

氮肥施用量对冬小麦氮肥利用率及土壤剖面NO － / 3－N动态分布的影响     

刘敏超  温小乐 《广东海洋大学学报》2000,20(2)

通过 6个氮水平小区试验 ,研究了不同氮肥用量对冬小麦氮肥利用率和土壤剖面 NO3 -- N动态分布的影响。结果表明 ,氮肥利用率有随施氮量的增加而递减的趋势 ;土壤剖面 NO3 -- N含量则有随氮肥施用量增加而增加的趋势 ,而在同一氮水平下 ,从土壤表层到深层 (10 0 cm) ,则有递减的趋势。在冬小麦生育期中 ,以开花期 80～ 10 0 cm土壤剖面累积的 NO3 -- N量最多 ,因此最有可能淋洗出根层 ,对地下水造成污染  相似文献   

Simple parameterisations for describing N and P diagenetic processes: Application in the North Sea   总被引：1，自引：0，他引：1  

Nathalie Gypens  Christiane Lancelot 《Progress in Oceanography》2008,76(1):89-110

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