Light effects on Crassulacean acid metabolism in the submerged aquatic plant Isoetes kirkii A. Braun     

M. R. Rattray  D. R. Webb  J. M. A. Brown 《新西兰海洋与淡水研究杂志》2013,47(3-4):465-470

In the submerged aquatic CAM plant, Isoetes kirkii A. Braun, light was shown to be the environmental factor having the major influence on daily did malic acid/titratable acid fluctuations. In Lake Taupo (New Zealand), a large oligotrophic lake, seasonal variation in the level of did fluctuations was demonstrated and this corresponded to changes in temperature, light, and daylength while Total Inorganic Carbon (TIC) remained relatively constant. However, in situ shading experiments demonstrated that, at any one time, the diel acid fluctuations were controlled by the ambient light levels as the other variables were constant. Laboratory experiments supported this and also showed that there was a close relationship between photosynthetic rates and de‐acidification when related to light intensity.  相似文献   

电感耦合等离子体法测定灰岩中的钙镁钾钠铝钛铁锰     

伦会荣  李玉明 《山东地质》2013,(10):109-112

灰岩样品的主要成分为碳酸钙,而镁、钾、钠、铝、钛、铁、锰的含量非常低,测试的灵敏度要求很高。该文采用一次溶矿电感耦合等离子体法直接测试灰岩中的镁、钾、钠、铝、钛、铁、锰。实验表明：在5％的盐酸介质中测试镁、钾、钠、铝、钛、铁、锰能取得很好的效果。通过测试国家标准样品,与国家标准值相比较,分析结果基本一致,准确度和精密度均令人满意,镁、钾、钠、铝、钛、铁、锰元素的相对标准偏差≤0．07％。钙元素的标准偏差≤0．15％。  相似文献   

长江口邻近海域溶解氧的时空分布及影响因素研究     

孙毅  吕方辉  陈钊  刁新源  姜金光  魏传杰  潘俊 《海洋科学》2021,45(12):86-96

基于2018年早春和夏季长江口邻近海域的调查数据,分析溶解氧(DO)的时空分布,并讨论其影响因素.结果表明,夏季DO浓度变化范围为1.58～9.37 mg/L,浮游生物光合作用产生的DO是夏季表层水体过饱和的主要因素;夏季调查海域受台湾暖流北上引起海水层化加强,同时水体富营养化导致表层生物大量繁殖所引起有机碎屑的沉降和耗氧分解作用是底层低氧区存在的主要因素.夏季在台湾暖流影响下底层水体表观耗氧量(AOU)与营养盐成正相关关系,底层有机物耗氧降解过程与营养盐的再生密切相关.早春DO浓度变化范围为7.90～10.1 mg/L,长江口外北部海域和浙江近岸海域海水混合均匀,DO浓度主要受温度控制,而台湾暖流影响区海水出现层化现象,其低DO含量也为低氧区的形成奠定了基础.  相似文献   

Does a general relationship exist between fluorescent dissolved organic matter and microbial respiration?—The case of the dark equatorial Atlantic Ocean     

《Deep Sea Research Part I: Oceanographic Research Papers》2014

The distributions of humic-like fluorescent dissolved organic matter (at excitation/emission wavelengths of 340 nm/440 nm, F(340/440)) and apparent oxygen utilization (AOU) are determined from water samples taken at 27 stations along 7.5°N, in the equatorial Atlantic Ocean. The relationship between F(340/440) and AOU is evaluated. The influence of water mass mixing is removed through multiple regressions of both F(340/440) and AOU with salinity and temperature for the ocean interior. A general and significant relationship between the residuals of F(340/440) and AOU is found for the entire water column deeper than 200 m (R²=0.79, n=360, p-value <0.001), endorsing the idea that changes in fluorescence intensity are directly related to in situ oxidation of organic matter by microbial activity in the dark equatorial Atlantic Ocean. In addition, we analyse and discuss the relationships between the residuals of F(340/440) and AOU for all individual water masses.  相似文献   

The relationships between particulate and soluble alkaline phosphatase activities and the concentration of phosphorus dissolved in the seawater of Toulon Bay (NW Mediterranean)     

Gérard Bogé  Magali Lespilette  Dominique Jamet  Jean-Louis Jamet 《Marine pollution bulletin》2013

The activities of particulate and soluble phosphatase were analyzed monthly for 1 year in the coastal ecosystems of the NW Mediterranean Sea. The mean contribution of the particulate activity increased from 56% at an MUF-P concentration of 30 μM to 77% at 0.04 μM. This particulate activity was negatively correlated with the DIP, DOP and TDP concentrations when the activities were related to the seawater volume, chlorophyll a or the protein concentration. The TDP correlations were highly significant (p: 0.001). The DOP correlations were significant (p: 0.04) and became highly significant (p: 0.009) at low DIP concentrations (<0.13 μM). The DIP correlations were significant (p: 0.04) only at low DOP concentrations (<0.18 μM). Thus, the effects of seawater DIP and DOP were found to be linked. The soluble activity exhibited distinct phosphatase fractions with high (0.5–29.5 μM) and low (0.02–2 μM) Km values, but none exhibited significant correlations with phosphorus compounds.  相似文献   

Indicators of microbial beach water quality: Preliminary findings from Teluk Kemang beach,Port Dickson (Malaysia)     

《Marine pollution bulletin》2013,77(1-2):417-419

This study aims to determine the concentrations of total coliforms and Escherichia coli (E. coli) in beach water, Teluk Kemang beach. This study was also aimed to determine relationship between total coliforms, E. coli and physicochemical parameters. As perceived health symptoms among beach visitors are rarely incorporated in beach water studies, this element was also assessed in this study. A total of eight water sampling points were selected randomly along Teluk Kemang beach. Total coliforms concentrations were found between 20 and 1940 cfu/100 ml. E. coli concentrations were between 0 and 90 cfu/100 ml. Significant correlations were found between total coliforms and E. coli with pH, temperature and oxidation reduction potential. Skin and eyes symptoms were the highest reported though in small numbers. Microbiological water quality in Teluk Kemang public beach was generally safe for recreational activities except sampling location near with sewage outfall.  相似文献   

徕卡全站仪数据编码加载程序的开发应用     

林云辉 《北京测绘》2013,(2):86-90,85

为了解决徕卡全站仪数据编码加载的问题;采用C#语言对徕卡全站仪数据编码加载程序的方法;从全站仪数字测图作业方法的编码、属性、图层方面进行了论述,揭示出存储在具有直接存储性能的介质上的关联数据文件:编码、属性、图层一应俱全。试验结果表明:用C#语言编程加载编码,验证了徕卡全站仪数字测图外业数据采集和内业软件成图的衔接具有完整性;试验结论达到了徕卡全站仪外业数据采集和内业软件成图的数据整体效果,有助于徕卡全站仪数据编码加载程序的连通问题。  相似文献   

使用全站仪对GPS边长检验问题探讨     

张海港 《北京测绘》2013,(6):110-111,67

通过分析GPS基线边长、全站仪边长、投影变形,对检验方法进行了说明,并用实际数据探讨用全站仪对GPS边长的检验方法及需要关注的问题.  相似文献   

Advance in Studies of Dissolved Organic Carbon Flux in Wetland Ecosystem     

KONG Fanting  LI Yue  XI Min  KONG Fanlong  CHEN Wan 《湿地科学》2013,11(3)

  相似文献   

Input data measurement-induced uncertainty in watershed modelling     

Abhijit Patil 《水文科学杂志》2013,58(1):118-133

Abstract

This study presents a new methodology for estimation of input data measurement-induced uncertainty in simulated dissolved oxygen (DO) and nitrate-nitrogen (NO₃-N) concentrations using the Hydrological Simulation Program–FORTRAN (HSPF) model and data from the Amite River, USA. Simulation results show that: (1) a multiplying factor of 1.3 can be used to describe the maximum error in temperature measurements; similarly, a multiplying factor of 1.9 was estimated to accommodate the maximum of ±5% error in rainfall measurements; (2) the uncertainty in simulated DO concentration due to positive temperature measurement errors can be described with a normal distribution, N(0.062, 0.567); (3) the uncertainty in simulated NO₃-N concentration due to rainfall measurement errors follows a generalized extreme value distribution; and (4) the probability density functions can be utilized to determine the measurement-induced uncertainty in simulated DO and NO₃-N concentrations according to the risk level acceptable in water quality management.

Editor D. Koutsoyiannis

Citation Patil, A. and Deng, Z.-Q., 2012. Input data measurement-induced uncertainty in watershed modelling. Hydrological Sciences Journal, 57 (1), 118–133.  相似文献