The effects of artificial ammonium enhancement on riverine periphytic diatom communities   总被引：2，自引：0，他引：2  

Joachim Hürlimann  Ferdinand Schanz 《Aquatic Sciences - Research Across Boundaries》1993,55(1):40-64

An experiment to ascertain the influence of artificially enhanced ammonium concentrations on riverine periphytic diatom communities was conducted during an 80 day period in winter 1988/89 (temperature: 5°C). During an initial 47 day enrichment phase, ammonium chloride at different concentrations was added to O₂-saturated river water in experimental channels. Compared to a control, the addition of 1.2 mg NH ₄ ⁺ -N·l^–1 resulted in only slight changes in the species composition of the diatom community. The addition of 5.1 mg NH ₄ ⁺ -N·l^–1 and more (60 µg NH₃-N·l^–1) resulted in a decrease in the biomass and a drastic change in the species composition. After the 42 day enrichment period, the diatom speciesFragilaria capucina var.vaucheriae, Navicula saprophila, Navicula atomus andGomphonema parvulum, all of which are known to be tolerant to organic pollution, were found with relative abundances of 44.8%, 35.6%, 2.3% and 1.5%, respectively. Changes in species composition of the periphytic diatom communities occurred within the first two weeks of the subsequent recovery phase. After a month of recovery, all periphytic diatom communities exhibited a high degree of structural similarity with the control.  相似文献   

自组装膜进样质谱系统及其在砂质沉积物异化硝酸盐还原研究中的应用     

谢成军  宋国栋  刘素美  唐继尧  张桂玲 《海洋学报》2020,42(2):22-29

沉积物中的异化硝酸盐还原过程对于海洋氮循环起着至关重要的作用。基于15N标记的培养技术是目前测定沉积物异化硝酸盐还原的主要手段。准确快速测定15N标记的产物(29N2、 30N2)是量化异化硝酸盐还原各个过程速率的关键。本研究自行组装膜进样质谱系统用于29N2和30N2的测定,对其测量条件进行了优化。结果表明,进样蠕动泵进样流速0.80 mL/min,进样时间3~3.5 min,恒温槽温度20~25℃,同时铜还原炉温度在300~600℃的条件下,^29N2/^28N2和^30N2/^28N2的测试精密度分别可以控制在0.1%和1%以内,比较适合29N2和30N2的测定。利用自组装的膜进样质谱系统结合15N标记的培养技术研究了青岛石老人沙滩沉积物中的异化硝酸盐还原过程。石老人沙滩沉积物不存在将硝酸盐完全还原为氮气好氧的反硝化。厌氧铵氧化、厌氧反硝化和异化硝酸盐还原为铵(Dissimilatory Nitrate Reduction to Ammonium,DNRA)的潜在速率(以湿沉积物N计)分别为(0.05±0.01) nmol/(cm^3·h),(2.32±0.21) nmol/(cm^3·h)和(1.02±0.15) nmol/(cm^3·h)。厌氧反硝化是硝酸盐异化还原主要的贡献者,其比例接近70%,其次是DNRA,比例可达30%,而厌氧铵氧化的贡献最低,仅为1%。在N2产生过程中,主要贡献者是反硝化,厌氧铵氧化的贡献仅为2%。  相似文献   

Suspended solids induce increasing microbial ammonium recycling along the river-estuary continuum of the Yangtze River     

Jingya Xue  Zhonghua Zhao  Xiaolong Yao  Weiting Liu  Lu Zhang 《水文研究》2021,35(8):e14345

Many large rivers worldwide are enriched with high levels of suspended solids (SS), which are known to be hotspots of many nitrogen (N) transformation processes (e.g., denitrification, nitrification). However, the influence of SS on microbial ammonium (NH₄⁺) recycling remains unclear. Water column NH₄⁺ regeneration rates (REGs) and potential uptake rates (U_pots) as well as community biological NH₄⁺ demand (CBAD) was measured in the river-estuary continuum of the third longest river in the world—Yangtze River, which has dramatic SS gradients. We found that REGs, U_pots, and CBAD all increased downriver, with higher REGs, U_pots, and CBAD in the estuary than in the river sections. The regeneration and uptake of NH₄⁺ were nearly balanced in the river sections, while the positive CBAD in the estuary indicated obvious NH₄⁺ demand of microbes. Concentrations of SS, which also control the content of chemical oxygen demand and particulate N, were the main factor influencing NH₄⁺ recycling rates and CBAD. SS-induced regenerated NH₄⁺ in the river-estuary continuum of Yangtze River was estimated to be 11.02 × 10⁸ kg N yr⁻¹ and accounted for about 14% of total N inputs, suggesting that regenerated NH₄⁺ is an important N source for microbes and may influence nutrient dynamics in lower coasts. To our knowledge, this is the first study to report NH₄⁺ recycling in Yangtze River with an emphasis on its influencing factors and contribution to N budgets.  相似文献   

Benthic metabolism and the fate of dissolved inorganic nitrogen in intertidal sediments     

W.P. Porubsky  N.B. Weston  S.B. Joye   《Estuarine, Coastal and Shelf Science》2009,83(4):392-402

We determined patterns of benthic metabolism and examined the relative importance of denitrification (DNF) and dissimilatory nitrate reduction to ammonium (DNRA) as sinks for nitrate (NO₃⁻) in intertidal sediments in the presence and absence of benthic microalgal (BMA) activity. By influencing the activity of BMA, light regulated the metabolic status of the sediments, and, in turn, exerted strong control on sediment nitrogen dynamics and the fate of inorganic nitrogen. A pulsed addition of ¹⁵N-labeled NO₃⁻ tracked the effect and fate of dissolved inorganic nitrogen (DIN) in the system. Under illuminated conditions, BMA communities influenced benthic fluxes directly, via DIN uptake, and indirectly, by altering the oxygen penetration depth. Under dark hypoxic and anoxic conditions, the fate of water column NO₃⁻ was determined largely by three competing dissimilatory reductive processes; DNF, DNRA, and, on one occasion, anaerobic ammonium oxidation (anammox). Mass balance of the added ¹⁵N tracer illustrated that DNF accounted for a maximum of 48.2% of the ¹⁵NO₃⁻ reduced while DNRA (a minimum of 11.4%) and anammox (a minimum of 2.2%) accounted for much less. A slurry experiment was employed to further examine the partitioning between DNF and DNRA. High sulfide concentrations negatively impacted rates of both processes, while high DOC:NO₃⁻ ratios favored DNRA over DNF.  相似文献   

海洋环境中的厌氧氨氧化细菌与厌氧氨氧化作用   总被引：1，自引：0，他引：1  

姚鹏  于志刚 《海洋学报》2011,33(4):1-8

厌氧氨氧化是细菌在厌氧条件下将氨氮氧化成氮气的过程,主要应用在污水处理反应器中,最近几年发现在海洋环境中也广泛存在,并在海洋氮循环过程中发挥了重要作用,代表了海洋中一个巨大的氮汇,对碳循环和全球气候变化也有重要影响.梯烷膜脂结构独特,是厌氧氨氧化细菌的化学生物标志物,具有化学分类与古海洋学应用潜力.厌氧氨氧化作用及厌氧...  相似文献   

Impact of different forcing factors on N:P balance in a semi-enclosed bay: The Gulf of Trieste (North Adriatic Sea)     

M. Lipizer  G. Cossarini 《Continental Shelf Research》2011,31(16):1651-1662

The availability and partition of nitrogen (N) and phosphorus (P) in inorganic and organic compartments, as well as their stoichiometric ratio, are influenced by both physical and biological forcing factors. On this basis, the temporal and spatial dynamics in N:P atomic ratios in different compartments may provide information on the functioning of marine ecosystems. Here we explore the relative importance of water temperature, river inputs, wind mixing, stratification, ingression of nutrient-depleted Eastern Adriatic Current and phytoplankton biomass on concentrations and ratios between nitrogen and phosphorus in a semi-enclosed bay (the Gulf of Trieste), using data from monitoring programs carried out during 8 years. Water samples are first classified in 6 water types based on N:P ratios in different components, and then relationships between water type space-time distribution and a set of forcing factors is sought. Results show that the gulf is characterised by relatively stable N:P ratios in all compartments (about 23-26), always exceeding the classical Redfield ratio. In the surface layer, however, nitrogen and phosphorus dynamics are decoupled because of river input and plankton productivity, and a significant spatial and temporal variability is observed in terms of stoichiometric balance, nutrient concentrations and partition among the different pools. Deviations from stable N:P ratios follow a seasonal evolution. In spring, continental inputs alter inorganic nutrient compartments (N:P up to 115); later on, during the seasonal succession of biological processes (e.g. late spring phytoplankton blooms, summer increase in microbial activities and autumn phytoplankton blooms), a change is also seen in the organic dissolved and particulate pools. Multivariate statistical analysis suggests that, among the considered forcing factors, the most relevant in modulating the N:P stoichiometry in the Gulf of Trieste are river inputs and ingression of the Eastern Adriatic Current (acting in opposite directions) along with phytoplankton dynamics. During the whole period, besides variations in N:P stoichiometry, in the Gulf of Trieste dissolved organic matter represents the largest pool of N and P, which can provide a source of nutrients for the planktonic community alternative to inorganic nutrient.  相似文献   

EDTA滴定法测定镍矿石中氧化钙     

郝原芳  徐英奎 《地质与资源》2014,23(6):580-582

建立了利用EDTA滴定法测定镍矿石中氧化钙的方法.考察了镍、碱度、沉淀剂、干扰元素、钙试剂对滴定的影响.确定了最佳的实验条件：温度50~60℃,陈化时间1 h,饱和草酸铵用量20 mL.方法检出限为1%,相对标准偏差1.1%~2.1%,回收率98.98%~102.6%.本方法灵敏度高,适合于镍矿石中氧化钙的快速测定.  相似文献   

陶瓷杯与蒸渗仪测定硝态氮和氨态氮淋溶的比较   总被引：1，自引：0，他引：1  

王琦  张恩和  师尚礼  刘青林  Keith Cameron 《干旱区地理》2015,38(2):298-304

土壤硝态氮（NO₃^--N）和氨态氮（NH4+-N）淋溶量测定方法因草本植物和土壤类型不同而异。试验采用陶瓷杯（ceramic suction cups）和蒸渗仪（lysimeters）分别测定草地土壤NO₃^--N和NH4+-N淋溶量。蒸渗仪直径为50 cm和深度为70 cm,土壤类型分别为新西兰Gorge silt loam、Mataura sandy loam和Lismore stony silt loam,重复4次。陶瓷杯水平插入蒸渗仪不锈钢筒,陶瓷杯插孔中心离不锈钢筒底部距离分别为35 cm（上陶瓷杯）和60 cm（下陶瓷杯）。在试验前,喷灌72 h冲洗蒸渗仪土壤溶液,使淋溶液NO₃^--N浓度接近0 mg·L^-1,然后1次性施加250 kg N·hm^-2尿素溶解液,用喷灌系统喷灌蒸渗仪,每周喷灌1次,喷灌系统误差使Gorge、Mataura和Lismore土壤喷灌强度分别为15.0、19.0和18.7 mm·h^-1,1次喷灌持续时间为3 h。在Gorge和Lismore土壤,陶瓷杯和蒸渗仪测定NO₃^--N淋溶量差异显著。在Gorge土壤,上陶瓷杯、下陶瓷杯和蒸渗仪测定NO₃^--N淋溶累计量分别为64、68和54 kg N·hm^-2,测定NH₄⁺-N淋溶累计量分别为0.43、0.49和0.43 kg N·hm^-2;在Mataura土壤,上陶瓷杯、下陶瓷杯和蒸渗仪测定NO₃^--N淋溶累计量分别为57、68和62 kg N·hm^-2,测定NH₄⁺-N淋溶累计量分别为0.51、0.37和0.23 kg N·hm^-2;在Lismore土壤,上陶瓷杯、下陶瓷杯和蒸渗仪测定NO₃^--N淋溶累计量分别为61、103和99 kg N·hm^-2,测定NH₄⁺-N淋溶累计量分别为1.70、2.24和2.04 kg N·hm^-2。在结构发育良好的Gorge和Lismore土壤,陶瓷杯不适合测定NO₃^--N淋溶量,但适合应用于砂土质地和发育不完善Mataura土壤。NH₄⁺-N淋溶累计量占NO₃^--N淋溶累计量的0.37%～2.93%,在测定和计算氮淋溶时,NH₄⁺-N淋溶可以忽略不计。  相似文献   

Distribution and abundance of demersal fish from trawl stations in the bay of plenty,New Zealand, 1961–63     

L. J. Tong  R. D. Elder 《新西兰海洋与淡水研究杂志》2013,47(1):49-66

Between March 1961 and January 1963 trawling surveys were carried out in the Bay of Plenty. Seasonal comparisons of catch weight were made for the four commercially important species, snapper, tarakihi, trevally, and gurnard, during 1962–63. Only trevally showed any marked seasonal variation in total catch. Tarakihi were most abundant in waters over 50 fathoms and snapper, trevally, and gurnard were most abundant in shallower depths. The best return for fishing effort came from the middle sector of the Bay. There was a marked absence of undersized tarakihi and trevally from the catches. A species composition list for the Bay of Plenty waters and a table of species abundance at the stations sampled has been compiled from the trawl catch data.  相似文献   

石墨炉原子吸收光谱法测定水质中的锂     

郑丽宁 《福建地质》2004,23(1):38-43

采用石墨炉原子吸收光谱法,以4％NH4NO3消除干扰。测定水样中的锂。试验了影响测定的主要因素。在优化实验条件下,方法的检出限为0．27μg／l,特征量为4．2pg,锂的质量浓度为0μg／l～30μg／l时,工作曲线线性关系良好。对于ρ(Li)=20．0μg／l样品的测定相对标准偏差(RSD,n=12)为3．03％。  相似文献