[Mechanisms for the increased fertilizer nitrogen use efficiency of rice in wheat-rice rotation system under combined application of inorganic and organic fertilizers].

Science.gov (United States)

Liu, Yi-Ren; Li, Xiang; Yu, Jie; Shen, Qi-Rong; Xu, Yang-Chun

2012-01-01

A pot experiment was conducted to study the effects of combined application of organic and inorganic fertilizers on the nitrogen uptake by rice and the nitrogen supply by soil in a wheat-rice rotation system, and approach the mechanisms for the increased fertilizer nitrogen use efficiency of rice under the combined fertilization from the viewpoint of microbiology. Comparing with applying inorganic fertilizers, combined application of organic and inorganic fertilizers decreased the soil microbial biomass carbon and nitrogen and soil mineral nitrogen contents before tillering stage, but increased them significantly from heading to filling stage. Under the combined fertilization, the dynamics of soil nitrogen supply matched best the dynamics of rice nitrogen uptake and utilization, which promoted the nitrogen accumulation in rice plant and the increase of rice yield and biomass, and increased the fertilizer nitrogen use efficiency of rice significantly. Combined application of inorganic and organic fertilizers also promoted the propagation of soil microbes, and consequently, more mineral nitrogen in soil was immobilized by the microbes at rice early growth stage, and the immobilized nitrogen was gradually released at the mid and late growth stages of rice, being able to better satisfy the nitrogen demand of rice in its various growth and development stages.

Total and inorganic arsenic in fish samples from Norwegian waters

DEFF Research Database (Denmark)

Julshamn, K.; Nilsen, B. M.; Frantzen, S.

2012-01-01

The contents of total arsenic and inorganic arsenic were determined in fillet samples of Northeast Arctic cod, herring, mackerel, Greenland halibut, tusk, saithe and Atlantic halibut. In total, 923 individual fish samples were analysed. The fish were mostly caught in the open sea off the coast......-assisted dissolution of the samples. The concentrations found for total arsenic varied greatly between fish species, and ranged from 0.3 to 110 mg kg–1 wet weight. For inorganic arsenic, the concentrations found were very low (...

Total dissolved atmospheric nitrogen deposition in the anoxic Cariaco basin

Science.gov (United States)

Rasse, R.; Pérez, T.; Giuliante, A.; Donoso, L.

2018-04-01

Atmospheric deposition of total dissolved nitrogen (TDN) is an important source of nitrogen for ocean primary productivity that has increased since the industrial revolution. Thus, understanding its role in the ocean nitrogen cycle will help assess recent changes in ocean biogeochemistry. In the anoxic Cariaco basin, the place of the CARIACO Ocean Time-Series Program, the influence of atmospherically-deposited TDN on marine biogeochemistry is unknown. In this study, we measured atmospheric TDN concentrations as dissolved organic (DON) and inorganic (DIN) nitrogen (TDN = DIN + DON) in atmospheric suspended particles and wet deposition samples at the northeast of the basin during periods of the wet (August-September 2008) and dry (March-April 2009) seasons. We evaluated the potential anthropogenic N influences by measuring wind velocity and direction, size-fractionated suspended particles, chemical traces and by performing back trajectories. We found DIN and DON concentration values that ranged between 0.11 and 0.58 μg-N m-3 and 0.11-0.56 μg-N m-3 in total suspended particles samples and between 0.08 and 0.54 mg-N l-1 and 0.02-1.3 mg-N l-1 in wet deposition samples, respectively. Continental air masses increased DON and DIN concentrations in atmospheric suspended particles during the wet season. We estimate an annual TDN atmospheric deposition (wet + particles) of 3.6 × 103 ton-N year-1 and concluded that: 1) Atmospheric supply of TDN plays a key role in the C and N budget of the basin because replaces a fraction of the C (20% by induced primary production) and N (40%) removed by sediment burial, 2) present anthropogenic N could contribute to 30% of TDN atmospheric deposition in the basin, and 3) reduced DON (gas + particles) should be a significant component of bulk N deposition.

Inorganic Nitrogen Application Affects Both Taxonomical and Predicted Functional Structure of Wheat Rhizosphere Bacterial Communities

Directory of Open Access Journals (Sweden)

Vanessa N. Kavamura

2018-05-01

Full Text Available The effects of fertilizer regime on bulk soil microbial communities have been well studied, but this is not the case for the rhizosphere microbiome. The aim of this work was to assess the impact of fertilization regime on wheat rhizosphere microbiome assembly and 16S rRNA gene-predicted functions with soil from the long term Broadbalk experiment at Rothamsted Research. Soil from four N fertilization regimes (organic N, zero N, medium inorganic N and high inorganic N was sown with seeds of Triticum aestivum cv. Cadenza. 16S rRNA gene amplicon sequencing was performed with the Illumina platform on bulk soil and rhizosphere samples of 4-week-old and flowering plants (10 weeks. Phylogenetic and 16S rRNA gene-predicted functional analyses were performed. Fertilization regime affected the structure and composition of wheat rhizosphere bacterial communities. Acidobacteria and Planctomycetes were significantly depleted in treatments receiving inorganic N, whereas the addition of high levels of inorganic N enriched members of the phylum Bacteroidetes, especially after 10 weeks. Bacterial richness and diversity decreased with inorganic nitrogen inputs and was highest after organic treatment (FYM. In general, high levels of inorganic nitrogen fertilizers negatively affect bacterial richness and diversity, leading to a less stable bacterial community structure over time, whereas, more stable bacterial communities are provided by organic amendments. 16S rRNA gene-predicted functional structure was more affected by growth stage than by fertilizer treatment, although, some functions related to energy metabolism and metabolism of terpenoids and polyketides were enriched in samples not receiving any inorganic N, whereas inorganic N addition enriched predicted functions related to metabolism of other amino acids and carbohydrates. Understanding the impact of different fertilizers on the structure and dynamics of the rhizosphere microbiome is an important step

Effects of the duration and inorganic nitrogen composition of a nutrient-rich patch on soil exploration by the roots of Lolium perenne in a heterogeneous environment.

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Nakamura, Ryoji; Kachi, N; Suzuki, J-I

2010-05-01

We investigated the growth of and soil exploration by Lolium perenne under a heterogeneous environment before its roots reached a nutrient-rich patch. Temporal changes in the distribution of inorganic nitrogen, i.e., NO(3)(-)-N and NH(4)(+)-N, in the heterogeneous environment during the experimental period were also examined. The results showed that roots randomly explored soil, irrespective of the patchy distribution of inorganic nitrogen and differences in the chemical composition of inorganic nitrogen distribution between heterogeneous and homogeneous environments. We have also elucidated the potential effects of patch duration and inorganic nitrogen distribution on soil exploration by roots and thus on plant growth.

Radiation induced changes in plasma total protein nitrogen and urinary total nitrogen in desert rodent and albino rats subjected to dietary protein deficiency

International Nuclear Information System (INIS)

Roushdy, H.; El-Husseini, M.; Saleh, F.

1986-01-01

The effect of gamma-irradiation on plasma total protein nitrogen and urinary total nitrogen was studied in the desert rodent, psammomy obesus obesus and albino rats subjected to dietary protein deficiency. In albino rats kept on high protein diet, the radiation syndrome resulted in urine retention, while in those kept on non-protein diet, such phenomenon was recorded only with the high radiation level of 1170r. Radiation exposure to 780 and 1170r caused remarkable diuresis in psammomys obesus obesus whereas they induced significant urine retention in albino rats. The levels of plasma total protein nitrogen and urinary total nitrogen were higher in albino rats maintained on high protein diet than in those kept on non-protein diet. Radiation exposure caused an initial drop in plasma total protein nitrogen concentration, concomitant with an initial rise in total urinary nitrogen, radiation exposure of psammomys obesus obesus caused significant increase in the levels of plasma protein nitrogen and urinary total nitrogen. Psammomys obesus obesus seemed to be more affected by radiation exposure than did the albino rats

Reducing dissolved inorganic nitrogen in surface runoff water from sugarcane production systems.

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Webster, A J; Bartley, R; Armour, J D; Brodie, J E; Thorburn, P J

2012-01-01

Nitrogen (N) lost from farms, especially as the highly bioavailable dissolved inorganic form, may be damaging Australia's Great Barrier Reef (GBR). As sugarcane is the dominant cropping system in GBR catchments, its N management practises are coming under increasing scrutiny. This study measured dissolved inorganic N lost in surface runoff water and sugarcane productivity over 3 years. The experiment compared the conventional fertiliser N application rate to sugarcane (average 180kg N/ha/year) and a rate based on replacing N exported in the previous crop (average 94kg N/ha/year). Dissolved inorganic N losses in surface water were 72%, 48% and 66% lower in the three monitored years in the reduced N fertiliser treatment. There was no significant difference in sugarcane yield between the two fertiliser N treatments, nor any treatment difference in soil mineral N - both of these results are indicators of the sustainability of the lower fertiliser N applications. Copyright © 2012 Elsevier Ltd. All rights reserved.

RESPONSE OF CHILE PEPPER (Capsicum annuum L. TO SALT STRESS AND ORGANIC AND INORGANIC NITROGEN SOURCES: II. NITROGEN AND WATER USE EFFICIENCIES, AND SALT TOLERANCE

Directory of Open Access Journals (Sweden)

Marco Antonio Huez Lopez

2011-07-01

Full Text Available The response to two nitrogen sources on water and nitrogen use efficiencies, and tolerance of salt-stressed chile pepper plants (Capsicum annuum L. cv. Sandia was investigated in a greenhouse experiment. Low, moderate and high (1.5, 4.5, and 6.5 dS m-1 salinity levels, and two rates of organic-N fertilizer (120 and 200 kg ha-1 and 120 kg ha-1 of inorganic fertilizer as ammonium nitrate were arranged in randomized complete block designs replicated four times. The liquid organic-N source was an organic, extracted with water from grass clippings. Water use decreased about 19 and 30% in moderate and high salt-stressed plants. Water use efficiency decreased only in high salt-stressed plants. Nitrogen use efficiency decreased either by increased salinity or increased N rates. An apparent increase in salt tolerance was noted when plants were fertilized with organic-N source compared to that of inorganic-N source.

A comparison of total bound nitrogen with the sum of inorganic nitrogen in the present partice in the German Water Regulation Act for monitoring of nitrogen compounds; Ein Vergleich des gesamten gebundenen Stickstoffs mit der Summe des anorganischen Stickstoffs in der derzeitigen Gesetzespraxis zur Ueberwachung auf Stickstoffverbindungen

Energy Technology Data Exchange (ETDEWEB)

Rinne, D.; Seckert-Knopp, W. [Landesamt fuer Wasserwirtschaft Rheinland-Pfalz, Mainz (Germany)

1997-11-01

The results of the analysis of nitrate, nitrite, ammonia, and total bound nitrogen (TN{sub b}) from 331 samples of municipal and 322 samples of industrial waste water effluents were compiled in the years 1990 to 1994. These data were evaluated due to - the comparison of the sum of inorganic nitrogen ({Sigma} N{sub anorg.}) of nitrate, nitrite, and ammonia to TN{sub b} in view of a planned exchange in the German Waste Water Regulation Act - the calculation of organic bound nitrogen (N{sub org.}) - the usefulness to generate sufficient data for balancing the `content of nitrogen` in water systems. The results of our investigations are: The analytical results from the sum of inorganic nitrogen and TN{sub b} are in very good agreement. In most cases the TN{sub b} values were higher than those of {Sigma} N{sub anorg.} This is plausible because most samples contain a certain amount of organic bound nitrogen. Therefore the differences between the results of this two analytical parameters should express the term `organic bound nitrogen` (N{sub org.}). This substraction is an excellent method to estimate this value without a further analytical procedure. The data from our investigation underline this quite clearly. In contrary to the determination of the single compounds ammonia, nitrate, and nitrite the TN{sub b} as a sum parameter is fast, instrument based, can be automated and shows a sufficient limit of determination. This method allows the evaluation of a high data density for water monitoring and balancing the `content of nitrogen` in water systems. A further advantage is the minimizing of errors when applying only one analytical method instead of three. (orig.) [Deutsch] Die Analysenergebnisse der Parameter Nitrit, Nitrat, Ammonium sowie die davon abgeleiteten Parameter `Summe anorganischer Stickstoff` ({Sigma} N{sub anorg.}) und `gesamter gebundener Stickstoff` (TN{sub b}) wurden fuer 331 Proben kommunaler und 322 Proben industrieller Abwasseranlagen aus den Jahren

Total and inorganic arsenic in dietary supplements based on herbs, other botanicals and algae—a possible contributor to inorganic arsenic exposure

DEFF Research Database (Denmark)

Hedegaard, Rikke Susanne Vingborg; Rokkjær, Inge; Sloth, Jens Jørgen

2013-01-01

The content of total and inorganic arsenic was determined in 16 dietary supplements based on herbs, other botanicals and algae purchased on the Danish market. The dietary supplements originated from various regions, including Asia, Europe and USA. The contents of total and inorganic arsenic...... was determined by inductively coupled plasma mass spectrometry (ICP-MS) and anion exchange HPLC-ICP-MS, respectively, were in the range of 0.58 to 5.0 mgkg−1 and 0.03 to 3.2 mg kg−1, respectively, with a ratio between inorganic arsenic and total arsenic ranging between 5 and 100 %. Consumption of the recommended...... dose of the individual dietary supplement would lead to an exposure to inorganic arsenic within the range of 0.07 to 13 μg day−1. Such exposure from dietary supplements would in worst case constitute 62.4 % of the range of benchmark dose lower confidence limit values (BMDL01 at 0.3 to 8 μg kg bw−1 kg−1...

Total and inorganic arsenic in fish, seafood and seaweeds--exposure assessment.

Science.gov (United States)

Mania, Monika; Rebeniak, Małgorzata; Szynal, Tomasz; Wojciechowska-Mazurek, Maria; Starska, Krystyna; Ledzion, Ewa; Postupolski, Jacek

2015-01-01

According to the European Food Safety Authority (EFSA), fish, seafood and seaweeds are foodstuffs that significantly contribute to dietary arsenic intake. With the exception of some algal species, the dominant compounds of arsenic in such food products are the less toxic organic forms. Both the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and EFSA recommend that speciation studies be performed to determine the different chemical forms in which arsenic is present in food due to the differences in their toxicity. Knowing such compositions can thus enable a complete exposure assessment to be made. Determination of total and inorganic arsenic contents in fish, their products, seafood and seaweeds present on the Polish market. This was then followed by an exposure assessment of consumers to inorganic arsenic in these foodstuffs. Total and inorganic arsenic was determined in 55 samples of fish, their products, seafood as well as seaweeds available on the market. The analytical method was hydride generation atomic absorption spectrometry (HGAAS), after dry ashing of samples and reduction of arsenic to arsenic hydride using sodium borohydride. In order to isolate only the inorganic forms of arsenic prior to mineralisation, samples were subjected to concentrated HCl hydrolysis, followed by reduction with hydrobromic acid and hydrazine sulphate after which triple chloroform extractions and triple 1M HCl re-extractions were performed. Exposure of adults was estimated in relation to the Benchmark Dose Lower Confidence Limit (BMDL0.5) as set by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) that resulted in a 0.5% increase in lung cancer (3.0 μg/kg body weight (b.w.) per day). Mean total arsenic content from all investigated fish samples was 0.46 mg/kg (90th percentile 0.94 mg/kg), whilst the inorganic arsenic content never exceeded the detection limit of the analytical method used (0.025 mg/kg). In fish products, mean total arsenic concentration was

Inorganic nitrogenous air pollutants, atmospheric nitrogen deposition and their potential ecological impacts in remote areas of western North America (Invited)

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Bytnerowicz, A.; Fenn, M. E.; Fraczek, W.; Johnson, R.; Allen, E. B.

2013-12-01

Dry deposition of gaseous inorganic nitrogenous (N) air pollutants plays an important role in total atmospheric N deposition and its ecological effects in the arid and semi-arid ecosystems. Passive samplers and denuder/ filter pack systems have been used for determining ambient concentrations of ammonia (NH3), nitric oxide (NO), nitrogen dioxide (NO2), and nitric acid vapor (HNO3) in the topographically complex remote areas of the western United States and Canada. Concentrations of the measured pollutants varied significantly between the monitoring areas. Highest NH3, NO2 and HNO3 levels occurred in southern California areas downwind of the Los Angeles Basin and in the western Sierra Nevada impacted by emissions from the California Central Valley and the San Francisco Bay area. Strong spatial gradients of N pollutants were also present in southeastern Alaska due to cruise ship emissions and in the Athabasca Oil Sands Region in Canada affected by oil exploitation. Distribution of these pollutants has been depicted by maps generated by several geostatistical methodologies within the ArcGIS Geostatistical Analyst (ESRI, USA). Such maps help to understand spatial and temporal changes of air pollutants caused by various anthropogenic activities and locally-generated vs. long range-transported air pollutants. Pollution distribution maps for individual N species and gaseous inorganic reactive nitrogen (Nr) have been developed for the southern portion of the Sierra Nevada, Lake Tahoe Basin, San Bernardino Mountains, Joshua Tree National Park and the Athabasca Oil Sands Region. The N air pollution data have been utilized for estimates of dry and total N deposition by a GIS-based inferential method specifically developed for understanding potential ecological impacts in arid and semi-arid areas. The method is based on spatial and temporal distribution of concentrations of major drivers of N dry deposition, their surface deposition velocities and stomatal conductance values

Factors influencing export of dissolved inorganic nitrogen by major rivers: A new seasonal, global-scale model

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Understanding sub-annual patterns of catchment dissolved inorganic nitrogen (DIN) export is critical for predicting and mitigating impacts of coastal eutrophication, such as algal blooms and hypoxic areas, which are often seasonal phenomena. We developed the first calibrated glob...

A series of inorganic solid nitrogen sources for the synthesis of metal nitride clusterfullerenes: the dependence of production yield on the oxidation state of nitrogen and counter ion.

Science.gov (United States)

Liu, Fupin; Guan, Jian; Wei, Tao; Wang, Song; Jiao, Mingzhi; Yang, Shangfeng

2013-04-01

A series of nitrogen-containing inorganic solid compounds with variable oxidation states of nitrogen and counter ions have been successfully applied as new inorganic solid nitrogen sources toward the synthesis of Sc-based metal nitride clusterfullerenes (Sc-NCFs), including ammonium salts [(NH4)xH(3-x)PO4 (x = 0-2), (NH4)2SO4, (NH4)2CO3, NH4X (X = F, Cl), NH4SCN], thiocyanate (KSCN), nitrates (Cu(NO3)2, NaNO3), and nitrite (NaNO2). Among them, ammonium phosphates ((NH4)xH(3-x)PO4, x = 1-3) and ammonium thiocyanate (NH4SCN) are revealed to behave as better nitrogen sources than others, and the highest yield of Sc-NCFs is achieved when NH4SCN was used as a nitrogen source. The optimum molar ratio of Sc2O3:(NH4)3PO4·3H2O:C and Sc2O3:NH4SCN:C has been determined to be 1:2:15 and 1:3:15, respectively. The thermal decomposition products of these 12 inorganic compounds have been discussed in order to understand their different performances toward the synthesis of Sc-NCFs, and accordingly the dependence of the production yield of Sc-NCFs on the oxidation state of nitrogen and counter ion is interpreted. The yield of Sc3N@C80 (I(h) + D(5h)) per gram Sc2O3 by using the N2-based group of nitrogen sources (thiocyanate, nitrates, and nitrite) is overall much lower than those by using gaseous N2 and NH4SCN, indicating the strong dependence of the yield of Sc-NCFs on the oxidation state of nitrogen, which is attributed to the "in-situ" redox reaction taking place for the N2-based group of nitrogen sources during discharging. For NH3-based group of nitrogen sources (ammonium salts) which exhibits a (-3) oxidation states of nitrogen, their performance as nitrogen sources is found to be sensitively dependent on the anion, and this is understood by considering their difference on the thermal stability and/or decomposition rate. Contrarily, for the N2-based group of nitrogen sources, the formation of Sc-NCFs is independent to both the oxidation state of nitrogen (+3 or +5) and the

Heavy metal, total arsenic, and inorganic arsenic contents of algae food products.

Science.gov (United States)

Almela, C; Algora, S; Benito, V; Clemente, M J; Devesa, V; Súñer, M A; Vélez, D; Montoro, R

2002-02-13

The total arsenic, inorganic arsenic, lead, cadmium, and mercury contents of 18 algae food products currently on sale in Spain were determined. The suitability of the analytical methodologies for this type of matrix was confirmed by evaluating their analytical characteristics. The concentration ranges found for each contaminant, expressed in milligrams per kilogram of dry weight, were as follows: total arsenic, 2.3-141; inorganic arsenic, 0.15-88; lead, mercury, 0.004-0.04. There is currently no legislation in Spain regarding contaminants in algae food products, but some of the samples analyzed revealed Cd and inorganic As levels higher than those permitted by legislation in other countries. Given the high concentrations of inorganic As found in Hizikia fusiforme, a daily consumption of 1.7 g of the product would reach the Provisional Tolerable Weekly Intake recommended by the WHO for an average body weight of 68 kg. A more comprehensive study of the contents and toxicological implications of the inorganic As present in the algae food products currently sold in Spain may be necessary, which might then be the basis for the introduction of specific sales restrictions.

Effects of Organic and Inorganic Nitrogen on the Growth and Production of Domoic Acid by Pseudo-nitzschia multiseries and P. australis (Bacillariophyceae) in Culture.

Science.gov (United States)

Martin-Jézéquel, Véronique; Calu, Guillaume; Candela, Leo; Amzil, Zouher; Jauffrais, Thierry; Séchet, Véronique; Weigel, Pierre

2015-11-26

Over the last century, human activities have altered the global nitrogen cycle, and anthropogenic inputs of both inorganic and organic nitrogen species have increased around the world, causing significant changes to the functioning of aquatic ecosystems. The increasing frequency of Pseudo-nitzschia spp. in estuarine and coastal waters reinforces the need to understand better the environmental control of its growth and domoic acid (DA) production. Here, we document Pseudo-nitzschia spp. growth and toxicity on a large set of inorganic and organic nitrogen (nitrate, ammonium, urea, glutamate, glutamine, arginine and taurine). Our study focused on two species isolated from European coastal waters: P. multiseries CCL70 and P. australis PNC1. The nitrogen sources induced broad differences between the two species with respect to growth rate, biomass and cellular DA, but no specific variation could be attributed to any of the inorganic or organic nitrogen substrates. Enrichment with ammonium resulted in an enhanced growth rate and cell yield, whereas glutamate did not support the growth of P. multiseries. Arginine, glutamine and taurine enabled good growth of P. australis, but without toxin production. The highest DA content was produced when P. multiseries grew with urea and P. australis grew with glutamate. For both species, growth rate was not correlated with DA content but more toxin was produced when the nitrogen source could not sustain a high biomass. A significant negative correlation was found between cell biomass and DA content in P. australis. This study shows that Pseudo-nitzschia can readily utilize organic nitrogen in the form of amino acids, and confirms that both inorganic and organic nitrogen affect growth and DA production. Our results contribute to our understanding of the ecophysiology of Pseudo-nitzschia spp. and may help to predict toxic events in the natural environment.

Total and inorganic arsenic in foods of the first Hong Kong total diet study.

Science.gov (United States)

Chung, Stephen Wai-cheung; Lam, Chi-ho; Chan, Benny Tsz-pun

2014-04-01

Arsenic (As) is a metalloid that occurs in different inorganic and organic forms, which are found in the environment from both natural occurrence and anthropogenic activity. The inorganic forms of As (iAs) are more toxic as compared with the organic As, but so far most of the occurrence data in food collected in the framework of official food control are still reported as total As without differentiating the various As species. In this paper, total As and iAs contents of 600 total diet study (TDS) samples, subdivided into 15 different food groups, were quantified by high-resolution inductively coupled plasma mass spectrometry (HR-ICP/MS) and hydride generation (HG) ICP/MS respectively. The method detection limits for both total As and iAs were 3 μg As kg(-1). As the samples were prepared for TDS, food items were purchased directly from the market or prepared as for normal consumption, i.e. table ready, in the manner most representative of and consistent with cultural habits in Hong Kong as far as practicable. The highest total As and iAs content were found in 'fish, seafood and their products' and 'vegetables and their products' respectively. Besides, this paper also presents the ratios of iAs and total As content in different ready-to-eat food items. The highest ratio of iAs to total As was found in 'vegetables and their products'. It is likely that iAs in vegetables maintained its status even after cooking.

Dissolved organic carbon biodegradability from thawing permafrost stimulated by sunlight rather than inorganic nitrogen

Science.gov (United States)

Liu, F.; Chen, L.; Zhang, B.; Wang, G.; Qin, S.; Yang, Y.

2017-12-01

Permafrost thaw could result in a large portion of frozen carbon being laterally transferred to aquatic ecosystems as dissolved organic carbon (DOC). During this delivery process, the size of biodegradable DOC (BDOC) determines the proportion of DOC mineralized by microorganisms and associated carbon loss to the atmosphere, which may further trigger positive carbon-climate feedback. Thermokarst is an abrupt permafrost thaw process that can enhance DOC export and also impact DOC processing through increased inorganic nitrogen (N) and sunlight exposure. However, it remains unclear how thermokarst-impacted BDOC responds to inorganic N addition and ultraviolet (UV) light irradiation. Here we explored the responses of DOC concentration, composition and its biodegradability to inorganic N and UV light in a typical thermokarst on the Tibetan Plateau, by combining field observation and laboratory incubation with spectra analyses (UV-visible absorption and three-dimensional fluorescence spectra) and parallel factor analyses. Our results showed that BDOC in thermokarst feature outflows was significantly higher than in reference water. Furthermore, inorganic N addition had no influence on thermokarst-impacted BDOC, whereas exposure to UV light significantly increased BDOC by as much as 2.3 times higher than the dark-control. Moreover, N addition and UV irradiation did not generate additive effects on BDOC. These results imply that sunlight rather than inorganic N can increase thermokarst-derived BDOC, potentially strengthening the positive permafrost carbon-climate feedback.

Nitrogen Transformation in a Long-Term Maize-Bean cropping system Amended with Repeated Applications of Organic and Inorganic Nutrient Sources

International Nuclear Information System (INIS)

Kibunja, C.N.

2002-01-01

Nitrogen is the most limiting element to agriculture productivity and inorganic fertilisers are too expensive for mos small-scale farmers in Kenya. The element is also susceptible to loss through leaching. There is need to improve the rate of field recoveries of applied nitrogen by the crops and the build-up of soil organic N reserves, which contribute to long term soil fertility. The long-term field plots at the National Agriculture Research Laboratories crop rotation and organic/inorganic management strategies. It was set up in 1976 to investigate the effect of continuous application of farmyard manure, crop residues and NP fertilisers on soil chemical properties and yields in a maize-bean rotation system. The main treatments are levels of inorganic fertilisers (N and P), 3 rates of manure application with or without stover retention. maize (Zea mays L.) hybrid '512' is planted at the start of the long rains season (March-Sept) while beans (Phaseolus vulgaris L) cultivar 'Mwezi moja' are planted during the following season (Oct-Jan) on residual fertiliser inputs. both plants are planted as mono-crops. The trial was used to follow the movement and distribution of available mineral N from 0 to 300 cm down the soil profile for a period of 2 years. Labelled 15 N fertiliser (10% a.e) as Calcium Ammonium Nitrate (CAN) at the rate 60 kg N ha -1 yr -1 was applied to maize in 1*2 m 2 micro-plots. Soils were sampled at various levels upto 3m, three times per season for two years and analyzed for available mineral N (NH 4 + N +No 3 - -N) and total nitrogen. The result of the first year indicated that the prevalent form of inorganic N found in the soil was in the form NO 3 - N. A substantial amount of NO 3 - N (1045-23.3 mg N kg soil - 1) was found in the plough layer (20 cm) of the soil at the beginning of the season. The concentration of NO 3 - -N in the first one metre decreased with depth as the crop matured due to plant uptake and loss through leaching. A bulge of

Factors influencing export of dissolved inorganic nitrogen by major rivers: A new, seasonal, spatially explicit, global model

Science.gov (United States)

Substantial effort has focused on understanding spatial variation in dissolved inorganic nitrogen (DIN) export to the coastal zone and specific basins have been studied in depth. Much less is known, however, about seasonal patterns and controls of coastal DIN delivery across larg...

Inorganic Nitrogen Deposition and Its Impacts on N:P-Ratios and Lake Productivity

Directory of Open Access Journals (Sweden)

Dag O. Hessen

2013-03-01

Full Text Available The pronounced increase in the cycling and deposition of biologically reactive dissolved inorganic nitrogen (DIN over large areas globally not only cause increased concentrations of DIN in surface waters, but it will also affect nutrient ratios in rivers, lakes and coastal areas. This review addresses the flux and fate of DIN, focusing NO3 in lakes of boreal and alpine catchments. Not only DIN-deposition, but also catchment properties strongly affect the concentrations of NO3 in lakes, as well as NO3:total P (TP ratios. This ratio displays an extreme variability, and does also serve as an indicator of shift between N and P-limitation of aquatic autotrophs. A high share of forests and bogs in the catchment generally decreases NO3:total P ratios, while alpine and subalpine catchments with sparse vegetation cover may have high NO3:total P ratios, especially in regions with high DIN-deposition. Several empirical and experimental studies indicate a shift from an initial N to P-limitation, but for N-limited lakes, an increased growth of phytoplankton, periphytes and macrophytes may be accredited to elevated inputs of DIN. An intensified P-limitation may also be a consequence of elevated DIN-deposition. This P-limitation may again yield higher C:P-ratios in autotrophs with negative impacts on grazers and higher trophic levels.

Nitrogen-doped ordered mesoporous carbon with a high surface area, synthesized through organic-inorganic coassembly, and its application in supercapacitors.

Science.gov (United States)

Song, Yanfang; Li, Li; Wang, Yonggang; Wang, Congxiao; Guo, Zaipin; Xia, Yongyao

2014-07-21

A new nitrogen-doped ordered mesoporous carbon (N-doped OMC) is synthesized by using an organic-inorganic coassembly method, in which resol is used as the carbon precursor, dicyandiamide as the nitrogen precursor, silicate oligomers as the inorganic precursors, and F127 as the soft template. The N-doped OMC possesses a surface area as high as 1374 m(2)  g(-1) and a large pore size of 7.4 nm. As an electrode material for supercapacitors, the obtained carbon exhibits excellent cycling stability and delivers a reversible specific capacitance as high as 308 F g(-1) in 1 mol L(-1) H(2)SO(4) aqueous electrolyte, of which 58 % of the capacity is due to pseudo-capacitance. The large specific capacitance is attributed to proper pore size distributions, large surface area, and high nitrogen content. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cascading influence of inorganic nitrogen sources on DOM production, composition, lability and microbial community structure in the open ocean.

Science.gov (United States)

Goldberg, S J; Nelson, C E; Viviani, D A; Shulse, C N; Church, M J

2017-09-01

Nitrogen frequently limits oceanic photosynthesis and the availability of inorganic nitrogen sources in the surface oceans is shifting with global change. We evaluated the potential for abrupt increases in inorganic N sources to induce cascading effects on dissolved organic matter (DOM) and microbial communities in the surface ocean. We collected water from 5 m depth in the central North Pacific and amended duplicate 20 liter polycarbonate carboys with nitrate or ammonium, tracking planktonic carbon fixation, DOM production, DOM composition and microbial community structure responses over 1 week relative to controls. Both nitrogen sources stimulated bulk phytoplankton, bacterial and DOM production and enriched Synechococcus and Flavobacteriaceae; ammonium enriched for oligotrophic Actinobacteria OM1 and Gammaproteobacteria KI89A clades while nitrate enriched Gammaproteobacteria SAR86, SAR92 and OM60 clades. DOM resulting from both N enrichments was more labile and stimulated growth of copiotrophic Gammaproteobacteria (Alteromonadaceae and Oceanospirillaceae) and Alphaproteobacteria (Rhodobacteraceae and Hyphomonadaceae) in weeklong dark incubations relative to controls. Our study illustrates how nitrogen pulses may have direct and cascading effects on DOM composition and microbial community dynamics in the open ocean. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Protein Losses and Urea Nitrogen Underestimate Total Nitrogen Losses in Peritoneal Dialysis and Hemodialysis Patients.

Science.gov (United States)

Salame, Clara; Eaton, Simon; Grimble, George; Davenport, Andrew

2018-04-28

Muscle wasting is associated with increased mortality and is commonly reported in dialysis patients. Hemodialysis (HD) and peritoneal dialysis (PD) treatments lead to protein losses in effluent dialysate. We wished to determine whether changes in current dialysis practice had increased therapy-associated nitrogen losses. Cross-sectional cohort study. Measurement of total protein, urea and total nitrogen in effluent dialysate from 24-hour collections from PD patients, and during haemodiafiltration (HDF) and haemodialysis (HD) sessions. One hundred eight adult dialysis patients. Peritoneal dialysis, high-flux haemodialysis and haemodiafiltration. Total nitrogen and protein losses. Dialysate protein losses were measured in 68 PD and 40 HD patients. Sessional losses of urea (13.9 [9.2-21.1] vs. 4.8 [2.8-7.8] g); protein (8.6 [7.2-11.1] vs. 6.7 [3.9-11.1] g); and nitrogen (11.5 [8.7-17.7] vs. 4.9 [2.6-9.5] g) were all greater for HD than PD, P losses were lower with HD 25.9 (21.5-33.4) versus 46.6 (27-77.6) g/week, but nitrogen losses were similar. We found no difference between high-flux HD and HDF: urea (13.5 [8.8-20.6] vs. 15.3 [10.5-25.5] g); protein (8.8 [7.3-12.2] vs. 7.6 [5.8-9.0] g); and total nitrogen (11.6 [8.3-17.3] vs. 10.8 [8.9-22.5] g). Urea nitrogen (UN) only accounted for 45.1 (38.3-51.0)% PD and 63.0 (55.3-62.4)% HD of total nitrogen losses. Although sessional losses of protein and UN were greater with HD, weekly losses were similar between modalities. We found no differences between HD and HDF. However, total nitrogen losses were much greater than the combination of protein and UN, suggesting greater nutritional losses with dialysis than previously reported. Copyright © 2018 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Factors influencing export of dissolved inorganic nitrogen by major rivers: A new seasonal, spatially explicit, global model - 2012

Science.gov (United States)

Background/Question/Methods Substantial effort has focused on understanding spatial variation in dissolved inorganic nitrogen (DIN) export to the coastal zone and specific basins have been studied in some depth. Much less is known, however, about seasonal patterns and zone and ...

Geographical variation in total and inorganic arsenic content of polished (white) rice.

Science.gov (United States)

Meharg, Andrew A; Williams, Paul N; Adomako, Eureka; Lawgali, Youssef Y; Deacon, Claire; Villada, Antia; Cambell, Robert C J; Sun, Guoxin; Zhu, Yong-Guan; Feldmann, Joerg; Raab, Andrea; Zhao, Fang-Jie; Islam, Rafiqul; Hossain, Shahid; Yanai, Junta

2009-03-01

An extensive data set of total arsenic analysis for 901 polished (white) grain samples, originating from 10 countries from 4 continents, was compiled. The samples represented the baseline (i.e., notspecifically collected from arsenic contaminated areas), and all were for market sale in major conurbations. Median total arsenic contents of rice varied 7-fold, with Egypt (0.04 mg/kg) and India (0.07 mg/kg) having the lowest arsenic content while the U.S. (0.25 mg/kg) and France (0.28 mg/kg) had the highest content. Global distribution of total arsenic in rice was modeled by weighting each country's arsenic distribution by that country's contribution to global production. A subset of 63 samples from Bangladesh, China, India, Italy, and the U.S. was analyzed for arsenic species. The relationship between inorganic arsenic contentversus total arsenic contentsignificantly differed among countries, with Bangladesh and India having the steepest slope in linear regression, and the U.S. having the shallowest slope. Using country-specific rice consumption data, daily intake of inorganic arsenic was estimated and the associated internal cancer risk was calculated using the U.S. Environmental Protection Agency (EPA) cancer slope. Median excess internal cancer risks posed by inorganic arsenic ranged 30-fold for the 5 countries examined, being 0.7 per 10,000 for Italians to 22 per 10,000 for Bangladeshis, when a 60 kg person was considered.

Determination of total and inorganic mercury in fish samples with on-line oxidation coupled to atomic fluorescence spectrometry

International Nuclear Information System (INIS)

Shao Lijun; Gan Wuer; Su Qingde

2006-01-01

An atomic fluorescence spectrometry system for determination of total and inorganic mercury with electromagnetic induction-assisted heating on-line oxidation has been developed. Potassium peroxodisulphate was used as the oxidizing agent to decompose organomercury compounds. Depending on the temperature selected, inorganic or total mercury could be determined with the same manifold. Special accent was put on the study of the parameters influencing the on-line digestion efficiency. The tolerance to the interference of coexisting ions was carefully examined in this system. Under optimal conditions, the detection limits (3σ) were evaluated to be 2.9 ng l -1 for inorganic mercury and 2.6 ng l -1 for total mercury, respectively. The relative standard deviations for 10 replicate determinations of 1.0 μg l -1 Hg were 2.4 and 3.2% for inorganic mercury and total mercury, respectively. The proposed method was successfully applied to the determination of total and inorganic mercury in fish samples

Gross Nitrogen Mineralization in Surface Sediments of the Yangtze Estuary

Science.gov (United States)

Liu, Min; Li, Xiaofei; Yin, Guoyu; Zheng, Yanling; Deng, Fengyu

2016-01-01

Nitrogen mineralization is a key biogeochemical process transforming organic nitrogen to inorganic nitrogen in estuarine and coastal sediments. Although sedimentary nitrogen mineralization is an important internal driver for aquatic eutrophication, few studies have investigated sedimentary nitrogen mineralization in these environments. Sediment-slurry incubation experiments combined with 15N isotope dilution technique were conducted to quantify the potential rates of nitrogen mineralization in surface sediments of the Yangtze Estuary. The gross nitrogen mineralization (GNM) rates ranged from 0.02 to 5.13 mg N kg-1 d-1 in surface sediments of the study area. The GNM rates were generally higher in summer than in winter, and the relative high rates were detected mainly at sites near the north branch and frontal edge of this estuary. The spatial and temporal distributions of GNM rates were observed to depend largely on temperature, salinity, sedimentary organic carbon and nitrogen contents, and extracellular enzyme (urease and L-glutaminase) activities. The total mineralized nitrogen in the sediments of the Yangtze Estuary was estimated to be about 6.17 × 105 t N yr-1, and approximately 37% of it was retained in the estuary. Assuming the retained mineralized nitrogen is totally released from the sediments into the water column, which contributed 12–15% of total dissolved inorganic nitrogen (DIN) sources in this study area. This result indicated that the mineralization process is a significant internal nitrogen source for the overlying water of the Yangtze Estuary, and thus may contribute to the estuarine and coastal eutrophication. PMID:26991904

Freshwater and Saline Loads of Dissolved Inorganic Nitrogen to Hood Canal and Lynch Cove, Western Washington

Science.gov (United States)

Paulson, Anthony J.; Konrad, Christopher P.; Frans, Lonna M.; Noble, Marlene; Kendall, Carol; Josberger, Edward G.; Huffman, Raegan L.; Olsen, Theresa D.

2006-01-01

Hood Canal is a long (110 kilometers), deep (175 meters) and narrow (2 to 4 kilometers wide) fjord of Puget Sound in western Washington. The stratification of a less dense, fresh upper layer of the water column causes the cold, saltier lower layer of the water column to be isolated from the atmosphere in the late summer and autumn, which limits reaeration of the lower layer. In the upper layer of Hood Canal, the production of organic matter that settles and consumes dissolved oxygen in the lower layer appears to be limited by the load of dissolved inorganic nitrogen (DIN): nitrate, nitrite, and ammonia. Freshwater and saline loads of DIN to Hood Canal were estimated from available historical data. The freshwater load of DIN to the upper layer of Hood Canal, which could be taken up by phytoplankton, came mostly from surface and ground water from subbasins, which accounts for 92 percent of total load of DIN to the upper layer of Hood Canal. Although DIN in rain falling on land surfaces amounts to about one-half of the DIN entering Hood Canal from subbasins, rain falling directly on the surface of marine waters contributed only 4 percent of the load to the upper layer. Point-source discharges and subsurface flow from shallow shoreline septic systems contributed less than 4 percent of the DIN load to the upper layer. DIN in saline water flowing over the sill into Hood Canal from Admiralty Inlet was at least 17 times the total load to the upper layer of Hood Canal. In September and October 2004, field data were collected to estimate DIN loads to Lynch Cove - the most inland marine waters of Hood Canal that routinely contain low dissolved-oxygen waters. Based on measured streamflow and DIN concentrations, surface discharge was estimated to have contributed about one-fourth of DIN loads to the upper layer of Lynch Cove. Ground-water flow from subbasins was estimated to have contributed about one-half of total DIN loads to the upper layer. In autumn 2004, the relative

REGIONAL ANALYSIS OF INORGANIC NITROGEN YIELD AND RETENTION IN HIGH-ELEVATION ECOSYSTEMS OF THE SIERRA NEVADA AND ROCKY MOUNTAINS

Science.gov (United States)

Yields and retention of inorganic nitrogen (DIN) and nitrate concentrations in surface runoff are summarized for 28 high elevation watersheds in the Sierra Nevada, California and Rocky Mountains of Wyoming and Colorado. Catchments ranged in elevation from 2475 to 3603 m and from...

Simplifying dynamic river water quality modelling: A case study of inorganic nitrogen dynamics in the Crocodile River (South Africa).

CSIR Research Space (South Africa)

Deksissa, T

2004-06-01

Full Text Available Quality Model No. 1, which is one of the most comprehensive basic river water quality models available in literature. The applicability of the simplified model in data limited situations was investigated using a case study of inorganic nitrogen (nitrate...

Deposition of inorganic particulate aerosols to vegetation - a new method of estimating

International Nuclear Information System (INIS)

Kwiecien, M.

1997-01-01

A new, direct method was developed for quantifying inorganic particulate aerosols trapped by the forest canopy, and for determining the resulting input of elements to a forest ecosystem. The method is based on direct measurements of only six parameters. Using this method, it is possible to determine the load of aerosols trapped by the forest canopy and deposited to leaves, as well as the load of aerosols falling to the forest floor by impaction on plants. It is also possible to estimate the aerosol input of soluble and insoluble elements to an ecosystem. With this new method it was found that the load of aerosols trapped by the canopy of a mixed forest locate din the Rybnik Coal Basin averaged 189.0 kg x ha -1 x growing season or 39.3% of the total inorganic particles reaching the ecosystem. The trapped aerosols provided 13.4 kg x ha -1 of soluble nitrogen and 0.91 kg x ha -1 of insoluble nitrogen over the growing season. At the same time, the input of soluble nitrogen from the atmosphere with rainfall to an open area averaged 13.9 kg x ha -1 , and the input of insoluble nitrogen with inorganic dusts averaged 1.4. kg x ha -1

Gas--liquid chromatographic determination of total inorganic iodine in milk

International Nuclear Information System (INIS)

Bakker, H.J.

1977-01-01

Total inorganic iodine in milk is determined by conversion to iodobutanone, which is quantitated by gas-liquid chromatography and electron capture detection. As little as 10 μg/L can be determined. The thyroid-active iodine content of milk can be determined rapidly with a relative standard deviation of 1.9%. Average recoveries for added iodide and iodine were 95.5 and 94.6%, respectively

Elements in rice from the Swedish market: 1. Cadmium, lead and arsenic (total and inorganic).

Science.gov (United States)

Jorhem, L; Astrand, C; Sundström, B; Baxter, M; Stokes, P; Lewis, J; Grawé, K Petersson

2008-03-01

A survey of the levels of cadmium, lead and arsenic in different types of rice available on the Swedish retail market was carried out in 2001--03. The types of rice included long and short grain, brown, white, and parboiled white rice. The mean levels found were as follows: total As: 0.20 mg kg(-1), inorganic As: 0.11 mg kg(-1); Cd: 0.024 mg kg(-1); and Pb: 0.004 mg kg(-1). ICP-MS was used for the determination of As (total and inorganic) after acid digestion. Lead and cadmium were determined using graphite furnace atomic absorption spectrometry (GFAAS) after dry ashing. In countries where rice is a staple food, it may represent a significant contribution in relation to the provisional tolerable weekly intake for Cd and inorganic As.

[Characteristics and Transport Patterns of Ammonia, Nitrites, Nitrates and Inorganic Nitrogen Flux at Epikarst Springs and a Subterranean Stream in Nanshan, Chongqing].

Science.gov (United States)

Zhang, Yuan-zhu; He, Qiu-fang; Jiang, Yong-jun; Li, Yong

2016-04-15

In a karst groundwater system, it develops complex multiple flows because of its special geological structure and unique physical patterns of aquifers. In order to investigate the characteristics and transport patterns of ammonia, nitrite and nitrate in epikarst water and subterranean stream, the water samples were collected monthly in a fast-urbanizing karst region. The results showed distinctive characteristics of three forms of inorganic nitrogen. The concentration of inorganic nitrogen was stable in the epikarst water while it was fluctuant in the subterranean stream. Epikarst water was less affected by rainfall and sewage compared with subterranean stream. In epikarst water, the nitrate concentration was much higher than the ammonia concentration. Dissolved inorganic nitrogen, mainly from non-point source pollution related to agricultural activities, passed in and out of the epikarst water based on a series of physical; chemical and biological processes in the epikarst zone, such as ammonification, adsorption and nitrification. On the contrary, subterranean stream showed a result of NH₄⁺-N > NO₃⁻-N in dry seasons and NO₃⁻-N > NH₄⁺-N in rainy seasons. This can be due to the fact that sanitary and industrial sewage flowed into subterranean river through sinkholes, fissures and grikes in dry season. Dissolved inorganic nitrogen in subterranean river was mainly from the non-point source pollution in wet season. Non-point source pollutants entered into subterranean water by two transport ways, one by penetration along with vadose flow through fissures and grikes, and the other by conduit flow through sinkholes from the surface runoff, soil water flow and epikarst flow. The export flux of DIN was 56.05 kg · (hm² · a)⁻¹, and NH₄⁺-N and NO₃⁻-N accounted for 46.03% and 52.51%, respectively. The contributions of point-source pollution and non point-source pollution to the export flux of DIN were 25.08% and 74.92%, respectively, based on run

[Effects of organic-inorganic mixed fertilizers on rice yield and nitrogen use efficiency].

Science.gov (United States)

Zhang, Xiao-li; Meng, Lin; Wang, Qiu-jun; Luo, Jia; Huang, Qi-wei; Xu, Yang-chun; Yang, Xing-ming; Shen, Qi-rong

2009-03-01

A field experiment was carried to study the effects of organic-inorganic mixed fertilizers on rice yield, nitrogen (N) use efficiency, soil N supply, and soil microbial diversity. Rapeseed cake compost (RCC), pig manure compost (PMC), and Chinese medicine residue compost (MRC) were mixed with chemical N, P and K fertilizers. All the treatments except CK received the same rate of N. The results showed that all N fertilizer application treatments had higher rice yield (7918.8-9449.2 kg x hm(-2)) than the control (6947.9 kg x hm(-2)). Compared with that of chemical fertilizers (CF) treatment (7918.8 kg x hm(-2)), the yield of the three organic-inorganic mixed fertilizers treatments ranged in 8532.0-9449.2 kg x hm(-2), and the increment was 7.7%-19.3%. Compared with treatment CF, the treatments of organic-inorganic mixed fertilizers were significantly higher in N accumulation, N transportation efficiency, N recovery rate, agronomic N use efficiency, and physiological N use efficiency. These mixed fertilizers treatments promoted rice N uptake and improved soil N supply, and thus, increased N use efficiency, compared with treatments CF and CK. Neighbor joining analysis indicated that soil bacterial communities in the five treatments could be classified into three categories, i.e., CF and CK, PMC and MRC, and RCC, implying that the application of exogenous organic materials could affect soil bacterial communities, while applying chemical fertilizers had little effect on them.

Abundance of Alnus incana ssp. rugosa in Adirondack Mountain shrub wetlands and its influence on inorganic nitrogen

International Nuclear Information System (INIS)

Kiernan, B.D.; Hurd, T.M.; Raynal, D.J.

2003-01-01

The presence of the nitrogen-fixing shrub, Alnus incana ssp. rugosa, influences the concentration of inorganic nitrogen in surface waters in the Adirondack Mountain region of northern New York. - The purpose of this research was to determine the abundance of the nitrogen-fixing shrub, Alnus incana ssp. rugosa (speckled alder), in shrub wetlands of the Adirondack Mountain region of New York State and to determine whether its abundance affects the concentration or accumulation of inorganic nitrogen in wetland substrates. Alder/willow wetlands are the second most common wetland type in the Adirondack region. The Adirondack Park Agency's digital GIS database of wetland types was used to determine the areal extent of alder/willow wetlands in the Adirondacks. Randomly selected wetlands were sampled to determine the size and abundance of alder. Alder densities averaged ∼7000 stems ha -1 and alder was present in 75% of the wetlands. As an indication of short-term accumulation of NO 3 - and NH 4 + in wetland substrates, ion exchange resins were used to sample ground water in high and low alder density wetlands as well as from wetlands lacking alder and dominated by conifers. Additionally, NO 3 - and NH 4 + concentrations in ground water samples were measured. NH 4 + accumulation levels from exchange resins were low for all wetland types while groundwater NH 4 + concentration was highest in the low-density alder sites. Wetlands with high alder density had approximately six times higher NO 3 - accumulation than other wetlands. Substrate groundwater NO 3 - concentrations in wetlands of high-density alder exceeded by three times levels in low or no alder wetlands, showing the importance of alder to local N budgets. To assess the recovery of shrub wetlands from acidification, future studies should determine the fate of fixed N in wetland systems

Chlorophyll meter reading and total nitrogen content applied as ...

African Journals Online (AJOL)

Ana Mascarello

The present study was aimed to assess the relationship between the reading of the chlorophyll meter and the total nitrogen (N) content ... devices to measure chlorophyll index (SPAD) and N content in the leaf. The nitrogen levels were found ... absorption of other nutrients and the production of carbohydrates. The methods ...

Changes in the content of total nitrogen and mineral nitrogen in the basil herb depending on the cultivar and nitrogen nutrition

Directory of Open Access Journals (Sweden)

Katarzyna Dzida

2013-04-01

Full Text Available Among fundamental nutrients, nitrogen fertilization is considered one of the most effective factors affecting both the yield and the quality of plant material. Nitrogen form used for fertilizing is also of great importance. The aim of this study was to investigate the impact of nitrogen nutrition (calcium nitrate, ammonium nitrate, and urea as well as (green, purple, and‘Fino Verde’ on the chemical composition and yielding of basil (Ocimum basilicumL.. After drying the plant material at a temperature of 60°C and milling, total nitrogen was determined by means of Kjeldahl method, while mineral nitrogen content (N-NH 4, N-NO 3 was analyzed in 2% acetic acid extract. Yield of fresh basil matter depended significantly on the variety grown. The highest yields were obtained from a cultivar of ‘Fino Verde’ fertilized with ammonium nitrate. The purple variety plants fertilized with urea were characterized by a largest amount of total nitrogen. The‘Fino Verde’cultivar fertilized with urea accumulated the least quantities of nitrates in the basil herb.

Plants' use of different nitrogen forms in response to crude oil contamination

International Nuclear Information System (INIS)

Nie Ming; Lu Meng; Yang Qiang; Zhang Xiaodong; Xiao Ming; Jiang Lifen; Yang Ji; Fang Changming; Chen Jiakuan; Li Bo

2011-01-01

In this study, we investigated Phragmites australis' use of different forms of nitrogen (N) and associated soil N transformations in response to petroleum contamination. 15 N tracer studies indicated that the total amount of inorganic and organic N assimilated by P. australis was low in petroleum-contaminated soil, while the rates of inorganic and organic N uptake on a per-unit-biomass basis were higher in petroleum-contaminated soil than those in un-contaminated soil. The percentage of organic N in total plant-assimilated N increased with petroleum concentration. In addition, high gross N immobilization and nitrification rates relative to gross N mineralization rate might reduce inorganic-N availability to the plants. Therefore, the enhanced rate of N uptake and increased importance of organic N in plant N assimilation might be of great significance to plants growing in petroleum-contaminated soils. Our results suggest that plants might regulate N capture under petroleum contamination. - Plant strategies of utilizing nitrogen in crude oil-contaminated soils.

Contributing factors in foliar uptake of dissolved inorganic nitrogen at leaf level

Energy Technology Data Exchange (ETDEWEB)

Wuyts, Karen, E-mail: karen.wuyts@uantwerpen.be [Laboratory of Environmental and Urban Ecology, Research Group ENdEMIC, Dept. Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Forest and Nature Lab (ForNaLab), Dept. Forest and Water Management, Ghent University, Geraardsbergsesteenweg 267, B-9090 Gontrode-Melle (Belgium); Adriaenssens, Sandy, E-mail: adriaenssens@irceline.be [Belgian Interregional Environment Agency (IRCEL-CELINE), Kunstlaan 10–11, B-1210 Brussels (Belgium); Staelens, Jeroen, E-mail: jeroen_staelens@yahoo.com [Flemish Environment Agency (VMM), Kronenburgstraat 45, B-2000 Antwerp (Belgium); Wuytack, Tatiana, E-mail: tatiana.wuytack@uantwerpen.be [Laboratory of Environmental and Urban Ecology, Research Group ENdEMIC, Dept. Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Van Wittenberghe, Shari, E-mail: shari.vanwittenberghe@uantwerpen.be [Laboratory of Environmental and Urban Ecology, Research Group ENdEMIC, Dept. Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Boeckx, Pascal, E-mail: pascal.boeckx@ugent.be [Isotope Bioscience Laboratory (ISOFYS), Dept. Applied Analytical and Physical Chemistry, Ghent University, Coupure Links 653, B-9000 Ghent (Belgium); Samson, Roeland, E-mail: roeland.samson@uantwerpen.be [Laboratory of Environmental and Urban Ecology, Research Group ENdEMIC, Dept. Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Verheyen, Kris, E-mail: kris.verheyen@ugent.be [Forest and Nature Lab (ForNaLab), Dept. Forest and Water Management, Ghent University, Geraardsbergsesteenweg 267, B-9090 Gontrode-Melle (Belgium)

2015-02-01

We investigated the influence of leaf traits, rainwater chemistry, and pedospheric nitrogen (N) fertilisation on the aqueous uptake of inorganic N by physiologically active tree leaves. Leaves of juvenile silver birch and European beech trees, supplied with NH{sub 4}NO{sub 3} to the soil at rates from 0 to 200 kg N ha{sup −1} y{sup −1}, were individually exposed to 100 μl of artificial rainwater containing {sup 15}NH{sub 4}{sup +} or {sup 15}NO{sub 3}{sup −} at two concentration levels for one hour. In the next vegetative period, the experiment was repeated with NH{sub 4}{sup +} at the highest concentration only. The N form and the N concentration in the applied rainwater and, to a lesser extent, the pedospheric N treatment and the leaf traits affected the aqueous foliar N uptake. The foliar uptake of NH{sub 4}{sup +} by birch increased when leaves were more wettable. High leaf N concentration and leaf mass per area enhanced the foliar N uptake, and NO{sub 3}{sup −} uptake in particular, by birch. Variation in the foliar N uptake by the beech trees could not be explained by the leaf traits considered. In the first experiment, N fertilisation stimulated the foliar N uptake in both species, which was on average 1.42–1.78 times higher at the highest soil N dose than at the zero dose. However, data variability was high and the effect was not appreciable in the second experiment. Our data suggest that next to rainwater chemistry (N form and concentration) also forest N status could play a role in the partitioning of N entering the ecosystem through the soil and the canopy. Models of canopy uptake of aqueous N at the leaf level should take account of leaf traits such as wettability and N concentration. - Highlights: • Foliar uptake of dissolved inorganic nitrogen (N) by potted trees was studied. • Leaves were individually exposed to rainwater drops containing {sup 15}NH{sub 4}{sup +} or {sup 15}NO{sub 3}{sup −}. • Foliar N uptake efficiency depended on

Nitrogen metabolism in a grapevine in vitro system

Directory of Open Access Journals (Sweden)

Nuria Llorens

2002-09-01

Full Text Available Ammonium, nitrate, nitrite, protein and individual and total amino acid contents were determined in grapevine (cv Sauvignon cultured in vitro. The enzyme activities of nitrate and nitrite reductases, glutamine synthetase, glutamate synthetase and dehydrogenase were also determined. The nitrogen taken up by the plants was 70% of the total nitrogen in the medium after 75 days of in vitro culture. Most of the nitrogen taken up was recovered in the leaves, yet only ammonia and amino acid concentrations were significantly higher in leaves. In roots, glutamine was the most abundant amino acid. In leaves, the most abundant amino acids were aspartate, glutamate, glutamine, alanine, arginine and g-aminobutirate. All enzyme activities were higher in roots than in leaves. These results suggest that both roots and leaves incorporate inorganic nitrogen into organic forms.

Sources of dissolved inorganic nitrogen in a coastal lagoon adjacent to a major metropolitan area, Miami Florida (USA)

International Nuclear Information System (INIS)

Swart, Peter K.; Anderson, William T.; Altabet, Mark A.; Drayer, Courtney; Bellmund, Sarah

2013-01-01

Highlights: • A range of biota (algae and sea grasses) shows enriched δ 15 N close to the coast. • Enriched signals are evident in the particulate and sedimentary organic material. • δ 15 N signals are correlated with high inputs of dissolved inorganic matter. • The enriched values support the presence of a sewage related component. • The δ 15 N could arise from the local landfill, injected wastewater, or septic systems. - Abstract: Between 2006 and 2007, a study was carried out to determine the relative importance of natural and anthropogenic input of nitrogen into Biscayne Bay (South Florida, USA) using δ 13 C and δ 15 N values of algae, seagrasses, and particulate organic material, δ 18 O and δ 15 N of the NO 3 - and δ 13 C of the dissolved inorganic carbon. The δ 15 N values of all components showed a strong east to west gradient approaching more positive values (+7 to +10‰) close to the land-sea interface. The nitrogen could have emanated from the local waste water treatment plant, septic systems within the region, or nitrogen which had been affected by denitrification and leached from the local landfill, wastewater which had been injected into the Floridan aquifer and leaked back to the surface, and/or some other as yet unidentified source. The measured NO 3 - δ 15 N and δ 18 O values indicated that the dissolved nitrate originated from anthropogenic sources and was fractionated during assimilation

Fertiliser management effects on dissolved inorganic nitrogen in runoff from Australian sugarcane farms.

Science.gov (United States)

Fraser, Grant; Rohde, Ken; Silburn, Mark

2017-08-01

Dissolved inorganic nitrogen (DIN) movement from Australian sugarcane farms is believed to be a major cause of crown-of-thorns starfish outbreaks which have reduced the Great Barrier Reef coral cover by ~21% (1985-2012). We develop a daily model of DIN concentration in runoff based on >200 field monitored runoff events. Runoff DIN concentrations were related to nitrogen fertiliser application rates and decreased after application with time and cumulative rainfall. Runoff after liquid fertiliser applications had higher initial DIN concentrations, though these concentrations diminished more rapidly in comparison to granular fertiliser applications. The model was validated using an independent field dataset and provided reasonable estimates of runoff DIN concentrations based on a number of modelling efficiency score results. The runoff DIN concentration model was combined with a water balance cropping model to investigate temporal aspects of sugarcane fertiliser management. Nitrogen fertiliser application in December (start of wet season) had the highest risk of DIN movement, and this was further exacerbated in years with a climate forecast for 'wet' seasonal conditions. The potential utility of a climate forecasting system to predict forthcoming wet months and hence DIN loss risk is demonstrated. Earlier fertiliser application or reducing fertiliser application rates in seasons with a wet climate forecast may markedly reduce runoff DIN loads; however, it is recommended that these findings be tested at a broader scale.

Chlorophyll meter reading and total nitrogen content applied as ...

African Journals Online (AJOL)

The present study was aimed to assess the relationship between the reading of the chlorophyll meter and the total nitrogen (N) content in the leaf in different parts of the crambe plant, depending on the doses of nitrogen applied to the canopy. Randomized block design in a split plot experimental design was used. The plots ...

Alternative futures of dissolved inorganic nitrogen export from the Mississippi River Basin: influence of crop management, atmospheric deposition, and population growth

Science.gov (United States)

Nitrogen (N) export from the Mississippi River Basin contributes to seasonal hypoxia in the Gulf of Mexico (GOM). We explored monthly dissolved inorganic N (DIN) export to the GOM for a historical year (2002) and two future scenarios (year 2022) by linking macroeonomic energy, ag...

Massive nitrogen loss from the Benguela upwelling system through anaerobic ammonium oxidation RID B-8834-2011

DEFF Research Database (Denmark)

Kuypers, MMM; Lavik, G.; Woebken, D.

2005-01-01

) and is commonly attributed to denitrification (reduction of nitrate to N-2 by heterotrophic bacteria). Here, we show that instead, the anammox process (the anaerobic oxidation of ammonium by nitrite to yield N-2) is mainly responsible for nitrogen loss in the OMZ waters of one of the most productive regions......In many oceanic regions, growth of phytoplankton is nitrogen-limited because fixation of N-2 cannot make up for the removal of fixed inorganic nitrogen (NH4+, NO2-, and NO3-) by anaerobic microbial processes. Globally, 30-50% of the total nitrogen loss occurs in oxygen-minimum zones (OMZs...... that anammox bacteria are responsible for massive losses of fixed nitrogen. We have identified and directly linked anammox bacteria to the removal of fixed inorganic nitrogen in the OMZ waters of an open-ocean setting. We hypothesize that anammox could also be responsible for substantial nitrogen loss from...

Emiliania Huxleyi (Prymnesiophyceae): Nitrogen-metabolism genes and their expression in response to external nitrogen souces

DEFF Research Database (Denmark)

Bruhn, Annette; LaRoche, Julie; Richardson, Katherine

2010-01-01

The availability and composition of dissolved nitrogen in ocean waters are factors that influence species composition in natural phytoplankton communities. The same factors affect the ratio of organic to inorganic carbon incorporation in calcifying species, such as the coccolithophore Emiliania...... huxleyi (Lohman) W. W. Hay et H. Mohler. E. huxleyi has been shown to thrive on various nitrogen sources, including dissolved organic nitrogen. Nevertheless, assimilation of dissolved nitrogen under nitrogen-replete and -limited conditions is not well understood in this ecologically important species....... In this study, the complete amino acid sequences for three functional genes involved in nitrogen metabolism in E. huxleyi were identified: a putative formamidase, a glutamine synthetase (GSII family), and assimilatory nitrate reductase. Expression patterns of the three enzymes in cells grown on inorganic...

Determination of nitrite, nitrate and total nitrogen in vegetable samples

Directory of Open Access Journals (Sweden)

Manas Kanti Deb

2007-04-01

Full Text Available Yellow diazonium cation formed by reaction of nitrite with 6-amino-1-naphthol-3-sulphonic acid is coupled with β-naphthol in strong alkaline medium to yield a pink coloured azo dye. The azo-dyes shows absorption maximum at 510 nm with molar absorptivity of 2.5 ×104 M-1 cm-1. The dye product obeys Beer's law (correlation coefficient = 0.997, in terms of nitrite concentration, up to 2.7 μg NO2 mL-1. The above colour reaction system has been applied successfully for the determination of nitrite, nitrate and total nitrogen in vegetable samples. Unreduced samples give direct measure for nitrite whilst reduction of samples by copperized-cadmium column gives total nitrogen content and their difference shows nitrate content in the samples. Variety of vegetables have been tested for their N-content (NO2-/NO3-/total-N with % RSD ranging between 1.5 to 2.5 % for nitrite determination. The effects of foreign ions in the determination of the nitrite, nitrate, and total nitrogen have been studied. Statistical comparison of the results with those of reported method shows good agreement and indicates no significant difference in precision.

Re-assessing the nitrogen signal in continental margin sediments: New insights from the high northern latitudes

Science.gov (United States)

Knies, Jochen; Brookes, Steven; Schubert, Carsten J.

2007-01-01

Organic and inorganic nitrogen and their isotopic signatures were studied in continental margin sediments off Spitsbergen. We present evidence that land-derived inorganic nitrogen strongly dilutes the particulate organic signal in coastal and fjord settings and accounts for up to 70% of the total nitrogen content. Spatial heterogeneity in inorganic nitrogen along the coast is less likely to be influenced by clay mineral assemblages or various substrates than by the supply of terrestrial organic matter (TOM) within eroded soil material into selected fjords and onto the shelf. The δ15N signal of the inorganic nitrogen ( δ15N inorg) in sediments off Spitsbergen seems to be appropriate to trace TOM supply from various climate- and ecosystem zones and elucidates the dominant transport media of terrigenous sediments to the marine realm. Moreover, we postulate that with the study of sedimentary δ15N inorg in the Atlantic-Arctic gateway, climatically induced changes in catchment's vegetations in high northern latitudes may be reconstructed. The δ15N org signal is primarily controlled by the availability of nitrate in the dominating ocean current systems and the corresponding degree of utilization of the nitrate pool in the euphotic zone. Not only does this new approach allow for a detailed view into the nitrogen cycle for settings with purely primary-produced organic matter supply, it also provides new insights into both the deposition of marine and terrestrial nitrogen and its ecosystem response to (paleo-) climate changes.

Effects of Nitrogen Fertilizers on the Growth and Nitrate Content of Lettuce (Lactuca sativa L.)

Science.gov (United States)

Liu, Cheng-Wei; Sung, Yu; Chen, Bo-Ching; Lai, Hung-Yu

2014-01-01

Nitrogen is an essential element for plant growth and development; however, due to environmental pollution, high nitrate concentrations accumulate in the edible parts of these leafy vegetables, particularly if excessive nitrogen fertilizer has been applied. Consuming these crops can harm human health; thus, developing a suitable strategy for the agricultural application of nitrogen fertilizer is important. Organic, inorganic, and liquid fertilizers were utilized in this study to investigate their effect on nitrate concentrations and lettuce growth. The results of this pot experiment show that the total nitrogen concentration in soil and the nitrate concentration in lettuce increased as the amount of nitrogen fertilizer increased. If the recommended amount of inorganic fertilizer (200 kg·N·ha−1) is used as a standard of comparison, lettuce augmented with organic fertilizers (200 kg·N·ha−1) have significantly longer and wider leaves, higher shoot, and lower concentrations of nitrate. PMID:24758896

Controls on inorganic nitrogen leaching from Finnish catchments assessed using a sensitivity and uncertainty analysis of the INCA-N model

Energy Technology Data Exchange (ETDEWEB)

Rankinen, K.; Granlund, K. [Finnish Environmental Inst., Helsinki (Finland); Futter, M. N. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden)

2013-11-01

The semi-distributed, dynamic INCA-N model was used to simulate the behaviour of dissolved inorganic nitrogen (DIN) in two Finnish research catchments. Parameter sensitivity and model structural uncertainty were analysed using generalized sensitivity analysis. The Mustajoki catchment is a forested upstream catchment, while the Savijoki catchment represents intensively cultivated lowlands. In general, there were more influential parameters in Savijoki than Mustajoki. Model results were sensitive to N-transformation rates, vegetation dynamics, and soil and river hydrology. Values of the sensitive parameters were based on long-term measurements covering both warm and cold years. The highest measured DIN concentrations fell between minimum and maximum values estimated during the uncertainty analysis. The lowest measured concentrations fell outside these bounds, suggesting that some retention processes may be missing from the current model structure. The lowest concentrations occurred mainly during low flow periods; so effects on total loads were small. (orig.)

Inorganic chemistry of earliest sediments

International Nuclear Information System (INIS)

Ochiai, E.I.

1983-01-01

A number of inorganic elements are now known to be essential to organisms. Chemical evolutionary processes involving carbon, hydrogen, nitrogen and oxygen have been studied intensively and extensively, but the other essential elements have been rather neglected in the studies of chemical and biological evolution. This article attempts to assess the significance of inorganic chemistry in chemical and biological evolutionary processes on the earth. Emphasis is placed on the catalytic effects of inorganic elements and compounds, and also on possible studies on the earliest sediments, especially banded iron formation and stratabound copper from the inorganic point of view in the hope of shedding some light on the evolution of the environment and the biological effects on it. (orig./WL)

The distribution and utilization of nitrogen in developing zea mays L. seedlings

International Nuclear Information System (INIS)

Watt, M.P.M. de O.C.

1987-01-01

During the first five days of germination, in the presence of NO - 3 - 15 N and N-SERVE, the nitrogen reserves of Zea mays L. caryopses accounted for 75% of the total nitrogen content of the seedlings. By day 7, exogenous nitrate contributed to all the inorganic nitrogen measured in the plant. Although NO - 3 - 15 N (94,2 atom % 15 N) was supplied throughout the germination process, and increasing pool of unlabelled nitrate was detected in both the grain and the seedling during this period. It appears that during germination in maize there is an oxidative pathway from reduced nitrogen in the reserve proteins to nitrate-nitrogen which is then supplied to the developing embryo. The levels of nitrate in the leaf increased towards the sheath, whereas other forms of nitrogen, nitrate reductase activity and capacity for nitrate accumulation increased in the opposite direction. Studies with mesophyll and bundle sheath protoplasts showed that the mesophyll tissue contributes over 80% of the total leaf content of inorganic nitrogen. Leaf tissue of Zea mays was found to have the capacity to assimilate nitrate in the dark, but at a lower rate than in the light. Oxygen did not restrict the initial rate of nitrate reduction in the dark. The rate of the in vivo nitrate reduction declined during the second hour of dark anaerobiosis, and was only restored upon supply of oxygen. Under dark anaerobic conditions nitrite accumulated and, on transfer to oxygen, the accumulate nitrite was reduced

Alternative futures of dissolved inorganic nitrogen export from ...

Science.gov (United States)

Nitrogen (N) export from the Mississippi River Basin contributes to seasonal hypoxia in the Gulf of Mexico (GOM). We explored monthly dissolved inorganic N (DIN) export to the GOM for a historical year (2002) and two future scenarios (year 2022) by linking macroeonomic energy, agriculture market, air quality, and agriculture land management models to a DIN export model. Future scenarios considered policies aimed at encouraging bioenergy crop production and reducing atmospheric N-emissions, as well as the effect of population growth and the states’ infrastructure plans on sewage fluxes. Model-derived DIN export decreased by about 9% (from 279 to 254 kg N km−2 year−1) between 2002 and 2022 due to a 28% increase in area planted with corn, 24% improvement in crop N-recovery efficiency (NRE, to 0.52), 22% reduction in atmospheric N deposition, and 23% increase in sewage inputs. Changes in atmospheric and sewage inputs had a relatively small effect on DIN export and the effect of bioenergy crop production depended on nutrient management practices. Without improved NRE, increased production of corn would have increased DIN export by about 14% (to 289 kg N km−2 year−1) between 2002 and 2022. Model results suggest that meeting future crop demand while reducing the areal extent of hypoxia could require aggressive actions, such improving basin-level crop NRE to 0.62 or upgrading N-removal capabilities in waste water treatment plants beyond current plans. Tile-dra

[Phylogenetic analysis and nitrogen removal characteristics of a heterotrophic nitrifying-aerobic denitrifying bacteria strain from marine environment].

Science.gov (United States)

Sun, Xuemei; Li, Qiufen; Zhang, Yan; Liu, Huaide; Zhao, Jun; Qu, Keming

2012-06-04

We determined the phylogenetic position of a heterotrophic nitrifying-aerobic denitrifying bacterium X3, and detected its nitrogen removal characteristics for providing evidence to explain the principle of heterotrophic nitrification-aerobic denitrification and to improve the process in purification of marine-culture wastewater. The evolutionary position of the strain was determined based on its morphological, physiological, biochemical characteristics and 16SrRNA gene sequence. The nitrification-denitrification ability of this strain was detected by detecting its nitrogen removal efficiency and growth on different inorganic nitrogen source. Strain X3 was identified as Halomonas sp. It grew optimally at salinity 3%, pH 8.5, C:N 10:1 at 28 degrees C, and it could still survive at 15% salinity. The removal of NH4+ -N, NO2(-) -N and NO3(-) -N was 98.29%, 99.07%, 96.48% respectively within 24 h. When three inorganic nitrogen existed simultaneously, it always utilized ammonia firstly, and the total inorganic nitrogen removal was higher than with only one nitrogen, suggesting that strain X3 has the ability of simultaneous nitrification and denitrification and completing the whole nitrogen removing process. Strain X3 belonged to the genus of Halomonas. It had strong simultaneous nitrification and denitrification capability and could live in high-salinity environment.

Organic and Inorganic Nitrogen Fertilization Effects on Some Physiological and Agronomical Traits of Chickpea (Cicer arietinum L. in Irrigated Condition

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Ali Namvar

2013-09-01

Full Text Available The effects of organic and inorganic nitrogen fertilization on some physiological and agronomical traits of chickpea (Cicer arietinum L. cv. ILC 482, investigated at the Experimental Farm of the Agriculture Faculty, University of Mohaghegh Ardabili. The trial was laid out in spilt plot design based on randomized complete block with four replications. Experimental factors were mineral nitrogen fertilizer at four levels (0, 50, 75 and 100 kg urea/ha in the main plots, and two levels of inoculation with Rhizobium bacteria (with and without inoculation as sub plots. N application and Rh. inoculation showed positive effects on physiological and agronomical traits of chickpea. The highest value of leaf RWC recorded in 50 kg urea/ha that was statistically in par with 75 kg urea/ha application while, usage of 75 kg urea/ha showed the maximum stem RWC. The maximum CMS obtained form application of 75 kg urea/ha. Chlorophyll content, leaf area index and grains protein content showed their maximum values in the highest level of nitrogen usage (100 kg urea/ha. Moreover, inoculated plants had the highest magnitudes of all physiological traits. In the case of agronomical traits, the highest values of plant height, number of primary and secondary branches, number of pods per plant, number of grains per plant, grain and biological yield were obtained from the highest level of nitrogen fertilizer (100 kg urea/ha and Rh. inoculation. Application of 75 kg urea/ha was statistically in par with 100 kg urea/ha in all of these traits. The results pointed out that some N fertilization (i.e. between 50 and 75 kg urea/ha as starter can be beneficial to improve growth, development, physiological traits and total yield of inoculated chickpea.

Effects of inorganic nitrogen forms on growth, morphology, nitrogen uptake capacity and nutrient allocation of four tropical aquatic macrophytes (Salvinia cucullata, Ipomoea aquatica, Cyperus involucratus and Vetiveria zizanioides)

DEFF Research Database (Denmark)

Jampeetong, Arunothai; Brix, Hans; Kantawanichkul, Suwasa

2012-01-01

This study assesses the growth and morphological responses, nitrogen uptake and nutrient allocation in four aquatic macrophytes when supplied with different inorganic nitrogen treatments (1) NH4+, (2) NO3−, or (3) both NH4+ and NO3−. Two free-floating species (Salvinia cucullata Roxb. ex Bory...... and Ipomoea aquatica Forssk.) and two emergent species (Cyperus involucratus Rottb. and Vetiveria zizanioides (L.) Nash ex Small) were grown with these N treatments at equimolar concentrations (500 M). Overall, the plants responded well to NH4+. Growth as RGR was highest in S. cucullata (0.12±0.003 d−1......) followed by I. aquatica (0.035 ±0.002 d−1), C. involucratus (0.03±0.002 d−1) and V. zizanioides (0.02±0.003 d−1). The NH4+ uptake rate was significantly higher than the NO3− uptake rate. The free-floating species had higher nitrogen uptake rates than the emergent species. The N-uptake rate differed between...

Technical Note: Comparison between a direct and the standard, indirect method for dissolved organic nitrogen determination in freshwater environments with high dissolved inorganic nitrogen concentrations

DEFF Research Database (Denmark)

Graeber, Daniel; Gelbrecht, Jörg; Kronvang, Brian

2012-01-01

Research on dissolved organic nitrogen (DON) in aquatic systems with high dissolved inorganic nitrogen (DIN, the sum of NO3–, NO2– and NH4+) concentrations is often hampered by high uncertainties regarding the determined DON concentration. The reason is that DON is determined indirectly...... accuracy at high DIN : TDN ratios, we investigated the DON measurement accuracy of this standard approach according to the DIN : TDN ratio and compared it to the direct measurement of DON by size-exclusion chromatography (SEC) for freshwater systems. For this, we used standard compounds and natural samples...... separation of DON from DIN. For SEC, DON recovery rates were 91–108% for five pure standard compounds and 89–103% for two standard compounds, enriched with DIN. Moreover, SEC resulted in 93–108% recovery rates for DON concentrations of natural samples at a DIN : TDN ratio of 0.8 and the technique...

Assessment of soil nitrogen and phosphorous availability under elevated CO2 and N-fertilization in a short rotation poplar plantation

NARCIS (Netherlands)

Lagomarsino, A.; Moscatelli, M.C.; Hoosbeek, M.R.; Angelis, de P.; Grego, S.

2008-01-01

Photosynthetic stimulation by elevated [CO2] is largely regulated by nitrogen and phosphorus availability in the soil. During a 6 year Free Air CO2 Enrichment (FACE) experiment with poplar trees in two short rotations, inorganic forms of soil nitrogen, extractable phosphorus, microbial and total

Total Nitrogen and Available Phosphorus Dynamics in Soils ...

African Journals Online (AJOL)

Total nitrogen and available phosphorus concentration of soils in three secondary forest fields aged 1, 5 and 10 years of age regenerating from degraded abandoned rubber plantation (Hevea brasiliensis) and a mature forest in the west African Rainforest belt in southern Nigeria were investigated in order to determine the ...

Inhibition of methane oxidation in slurry surface crust by inorganic nitrogen

DEFF Research Database (Denmark)

Duan, Yun-Feng; Elsgaard, Lars; Petersen, Søren O

2013-01-01

Livestock slurry is an important source of methane (CH4). Depending on dry matter content, a floating crust may form where methane-oxidizing bacteria (MOB) and CH4 oxidation activity have been found, suggesting that surface crusts may reduce CH4 emissions from slurry. However, it is not known how...... MOB in this environment interact with inorganic nitrogen (N). We studied inhibitory effects of ammonium (NH4+), nitrate (NO3–) and nitrite (NO2–) on potential CH4 oxidation in a cattle slurry surface crust. Methane oxidation was assayed at salt concentrations up to 500 mM at 100 and 10,000 ppmv...... headspace CH4. First-order rate constants were used to evaluate the strength of inhibition. Nitrite was the most potent inhibitor, reducing methanotrophic activity by up to 70% at only 1 mM NO2–. MOB were least sensitive to NO3–, tolerating up to 30 mM NO3– at 100 ppmv CH4 and 50 mM NO3– at 10,000 ppmv CH4...

Survey of total and inorganic arsenic content in blue mussels (Mytilus edulis L.) from Norwegian fiords: Revelation of unusual high levels of inorganic arsenic

DEFF Research Database (Denmark)

Sloth, Jens Jørgen; Julshamn, Kåre

2008-01-01

arsenic. Total arsenic was determined using inductively coupled plasma mass spectrometry (ICPMS) following microwave-assisted acidic digestion of the samples. Inorganic arsenic was determined using an anion-exchange HPLC-ICPMS method following microwave-assisted alkaline solubilization of the samples...

Impact of Tile Drainage on the Distribution of Concentration and Age of Inorganic Soil Nitrogen.

Science.gov (United States)

Woo, D.; Kumar, P.

2017-12-01

Extensive network of tile drainage network across the Midwestern United States, northern Europe and other regions of the world have enhanced agricultural productivity. Because of its impact on sub-surface flow patterns and moisture and temperature dynamics, it controls the nitrogen cycle in agricultural systems, and its influence on nitrogen dynamics plays a key role in determining the short- and long-term evolution of soil inorganic nitrogen concentration and age. The spatial mapping of nitrogen concentration and age under tile-drained fields has, therefore, the potential to open up novel solution to the vexing challenge of reducing environmental impacts while at the same time maintaining agricultural productivity. The objective of this study is to explore the impacts of tile drains on the age dynamics of nitrate, immobile ammonium, mobile ammonia/um, and non-reactive tracer (such as chloride) by implementing two mobile interacting pore domains to capture matrix and preferential flow paths in a coupled ecohydrology and biogeochemistry model, Dhara. We applied this model to an agricultural farm supporting a corn-soybean rotation in the Midwestern United States. It should be expected that the installation of tile drains decrease the age of soil nutrient due to nutrient losses through tile drainage. However, an increase in the age of mobile ammonia/um is observed in contrast to the cases for nitrate, immobile ammonium, and non-reactive tracer. These results arise because the depletion of mobile ammonia/um due to tile drainage causes a high mobility flux from immobile ammonium to mobile ammonia/um, which also carries a considerable amount of relatively old age of immobile ammonium to mobile ammonia/um. In addition, the ages of nitrate and mobile ammonia/um in tile drainage range from 1 to 3 years, and less than a year, respectively, implying that not considering age transformations between nitrogen species would result in substantial underestimation of nitrogen ages

[Studies on nitrogen, phosphorus and organic matter in ponds around Chaohu Lake].

Science.gov (United States)

Sun, Qing-ye; Ma, Xiu-ling; Yang, Gui-de; Chen, Zheng; Wu, Hong-lin; Xuan, Huai-xiang

2010-07-01

There are a lot of ponds around Chaohu Lake. According to location and runoff supply of ponds, the ponds are divided into three types: ponds inner vellage (PIV), ponds adjacent vellage (PAV) and ponds outer vellage (POV). The samples of water and sediment were collected from 136 ponds around Chaohu Lake and the contents of nitrogen, phosphorus and organic matter in water and sediments were analyzed in this study. The results showed that mean contents of total nitrogen (TN), NH4+ -N, NO3- -N, NO2- -N, total phosphorus (TP), soluble PO4(3-) -P and COD were 2.53, 0.65, 0.18, 0.02, 0.97, 0.38 and 51.58 mg x L(-1) in pond water, respectively; and mean contents of TN, NH4+ -N, NO3- -N, NO2- -N, TP, inorganic phosphorus (IP), organic phosphorus (OP) and loss of ignition (LOI) in pond sediment were 1575.36, 35.73, 13.30, 2.88, 933.19, 490.14, 414.75 mg x kg(-1) and 5.44%, respectively. The ponds of more than 90% presented eutrophication in the contents of total nitrogen and phosphorus in water. The contents of TN and NH4+ -N in water and sediment of PIV were significantly higher than that of POV. And the contents of inorganic nitrogen in pond water and sediment displayed a following order: NH4+ -N > NO3- -N > NO2- -N. Data analysis indicated that there was a significantly positive correlation between organic matter and total nitrogen and phosphorus in water and sediment. The nitrogen, phosphorus and organic matter in ponds mainly sourced farmlands and village land surface. The contents of nitrogen, phosphorus and organic matter in ponds were affected by location and runoff supply of ponds. By retaining nitrogen, phosphorus and organic matter in runoff, the ponds can effectively decrease nutrient content into Chaohu Lake.

Dissolved organic nitrogen recalcitrance and bioavailable nitrogen quantification for effluents from advanced nitrogen removal wastewater treatment facilities.

Science.gov (United States)

Fan, Lu; Brett, Michael T; Jiang, Wenju; Li, Bo

2017-10-01

The objective of this study was to determine the composition of nitrogen (N) in the effluents of advanced N removal (ANR) wastewater treatment plants (WWTPs). This study also tested two different experimental protocols for determining dissolved N recalcitrance. An analysis of 15 effluent samples from five WWTPs, showed effluent concentrations and especially effluent composition varied greatly from one system to the other, with total nitrogen (TN) ranging between 1.05 and 8.10 mg L -1 . Nitrate (NO 3 - ) accounted for between 38 ± 32% of TN, and ammonium accounted for a further 29 ± 28%. All of these samples were dominated by dissolved inorganic nitrogen (DIN; NO 3 -  + NH 4 + ), and uptake experiments indicated the DIN fraction was as expected highly bioavailable. Dissolved organic N (DON) accounted for 20 ± 11% for the total dissolved N in these effluents, and uptake experiments indicated the bioavailability of this fraction varied between 27 ± 26% depending on the WWTP assessed. These results indicate near complete DIN removal should be the primary goal of ANR treatment systems. The comparison of bioavailable nitrogen (BAN) quantification protocols showed that the dissolved nitrogen uptake bioassay approach was clearly a more reliable way to determine BAN concentrations compared to the conventional cell yield protocol. Moreover, because the nitrogen uptake experiment was much more sensitive, this protocol made it easier to detect extrinsic factors (such as biological contamination or toxicity) that could affect the accuracy of these bioassays. Based on these results, we recommend the nitrogen uptake bioassay using filtered and autoclaved samples to quantify BAN concentrations. However, for effluent samples indicating toxicity, algal bioassays will not accurately quantify BAN. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nitrogen Immobilization in Plant Growth Substrates: Clean Chip Residual, Pine Bark, and Peatmoss

Directory of Open Access Journals (Sweden)

Cheryl R. Boyer

2012-01-01

Full Text Available Rising costs of potting substrates have caused horticultural growers to search for alternative, lower-cost materials. Objectives of this study were to determine the extent of nitrogen immobilization and microbial respiration in a high wood-fiber content substrate, clean chip residual. Microbial activity and nitrogen availability of two screen sizes (0.95 cm and 0.48 cm of clean chip residual were compared to control treatments of pine bark and peatmoss in a 60-day incubation experiment. Four rates (0, 1, 2, or 3 mg of supplemental nitrogen were assessed. Peatmoss displayed little microbial respiration over the course of the study, regardless of nitrogen rate; followed by pine bark, 0.95 cm clean chip residual, and 0.48 cm clean chip residual. Respiration increased with increasing nitrogen. Total inorganic nitrogen (plant available nitrogen was greatest with peatmoss; inorganic nitrogen in other treatments were similar at the 0, 1, and 2 mg supplemental nitrogen rates, while an increase occurred with the highest rate (3 mg. Clean chip residual and pine bark were similar in available nitrogen compared to peatmoss. This study suggests that nitrogen immobilization in substrates composed of clean chip residual is similar to pine bark and can be treated with similar fertilizer amendments during nursery production.

Total Protein Content Determination of Microalgal Biomass by Elemental Nitrogen Analysis and a Dedicated Nitrogen-to-Protein Conversion Factor

Energy Technology Data Exchange (ETDEWEB)

Laurens, Lieve M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Olstad-Thompson, Jessica L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Templeton, David W [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2018-04-02

Accurately determining protein content is important in the valorization of algal biomass in food, feed, and fuel markets, where these values are used for component balance calculations. Conversion of elemental nitrogen to protein is a well-accepted and widely practiced method, but depends on developing an applicable nitrogen-to-protein conversion factor. The methodology reported here covers the quantitative assessment of the total nitrogen content of algal biomass and a description of the methodology that underpins the accurate de novo calculation of a dedicated nitrogen-to-protein conversion factor.

Geochemistry of inorganic nitrogen in waters released from coal-bed natural gas production wells in the Powder River Basin, Wyoming

Science.gov (United States)

Smith, Richard L.; Repert, Deborah A.; Hart, Charles P.

2009-01-01

Water originating from coal-bed natural gas (CBNG) production wells typically contains ammonium and is often disposed via discharge to ephemeral channels. A study conducted in the Powder River Basin, Wyoming, documented downstream changes in CBNG water composition, emphasizing nitrogen-cycling processes and the fate of ammonium. Dissolved ammonium concentrations from 19 CBNG discharge points ranged from 95 to 527 μM. Within specific channels, ammonium concentrations decreased with transport distance, with subsequent increases in nitrite and nitrate concentrations. Removal efficiency, or uptake, of total dissolved inorganic nitrogen (DIN) varied between channel types. DIN uptake was greater in the gentle-sloped, vegetated channel as compared to the incised, steep, and sparsely vegetated channel and was highly correlated with diel patterns of incident light and dissolved oxygen concentration. In a larger main channel with multiple discharge inputs (n = 13), DIN concentrations were >300 μM, with pH > 8.5, after 5 km of transport. Ammonium represented 25−30% of the large-channel DIN, and ammonium concentrations remained relatively constant with time, with only a weak diel pattern evident. In July 2003, the average daily large-channel DIN load was 23 kg N day−1entering the Powder River, an amount which substantially increased the total Powder River DIN load after the channel confluence. These results suggest that CBNG discharge may be an important source of DIN to western watersheds, at least at certain times of the year, and that net oxidation and/or removal is dependent upon the extent of contact with sediment and biomass, type of drainage channel, and time of day.

Structure of inorganic phosphorus-nitrogen tetrahedral compounds

International Nuclear Information System (INIS)

Vitola, A.; Ronis, J.; Avotins, V.; Millers, T.

1997-01-01

The structure analysis of phosphorus-nitrogen compounds has shown the possibility of the P(O,N) 4 tetrahedra to form various kinds of structures. The wide spectrum of the properties determined by the diversity of structures marks the considerable promise to the future application of phosphorus-nitrogen compounds

Total nitrogen and total phosphorus removal from brackish aquaculture wastewater using effective microorganism

Science.gov (United States)

Mohamad, K. A.; Mohd, S. Y.; Sarah, R. S.; Mohd, H. Z.; Rasyidah, A.

2017-09-01

Aquaculture is one of dominant food based industry in the world with 8.3% annual growth rate and its development had led to adverse effect on the environment. High nutrient production in form of nitrogenous compound and phosphorus contributed to environmental deterioration such as eutrophication and toxicity to the industry. Usage of Effective Microorganism (EM), one of the biological approaches to remove Total Nitrogen (TN) and Total Phosphorus (TP) in aquaculture pond was proposed. Samples were obtained from the Sea Bass intensive brackish aquaculture wastewater (AW) from fish farm at Juru, Penang and the parameters used to measure the removal of nitrogenous compounds include, pH, EM dosage, shaking, contact time and optimum variable conditions. From the study, for effective contact time, day 6 is the optimum contact time for both TN and TP with 99.74% and 62.78% removal respectively while in terms of optimum pH, the highest TN removal was at pH 7 with 66.89 %. The optimum dosage of EM is 1.5 ml with ratio 1:166 for 81.5 % TN removal was also found appropriate during the experiment. At varied optimum conditions of EM, the removal efficiency of TN and TP were 81.53% and 38.94% respectively while the removal mechanism of TN was highly dependent on the decomposition rate of specific bacteria such as Nitrobacter bacteria, Yeast and Bacillus Subtilis sp. The study has established the efficacy of EM's ability to treat excessive nutrient of TN and TP from AW.

Nitrogen mineralization from selected 15N-labelled crop residues and humus as affected by inorganic nitrogen

International Nuclear Information System (INIS)

Santos, J.A.

1987-01-01

The use of cover crops or crop residues as a source of N to succeeding crops has become a matter of increasing importance for economic and environmental reason. Greenhouse and field studies were conducted to determine the N contribution of four 15 N labelled crop residues, rye (Secale cereale L.), wheat (Triticum aestivum L.), crimson clover (Trifolium encarnatum L.), and hairy vetch (Vicia sativa L.), to successive crops and to evaluate the effect of different organic (ON) and inorganic N (IN) combinations on mineralization of the above residues. Total 15 N recovery from the residues ranged from 51% to 85% and 4% to 74% for the greenhouse and field studies, respectively

Effect of application of dairy manure, effluent and inorganic fertilizer on nitrogen leaching in clayey fluvo-aquic soil: A lysimeter study.

Science.gov (United States)

Fan, Jianling; Xiao, Jiao; Liu, Deyan; Ye, Guiping; Luo, Jiafa; Houlbrooke, David; Laurenson, Seth; Yan, Jing; Chen, Lvjun; Tian, Jinping; Ding, Weixin

2017-08-15

Dairy farm manure and effluent are applied to cropland in China to provide a source of plant nutrients, but there are concerns over its effect on nitrogen (N) leaching loss and groundwater quality. To investigate the effects of land application of dairy manure and effluent on potential N leaching loss, two lysimeter trials were set up in clayey fluvo-aquic soil in a winter wheat-summer maize rotation cropping system on the North China Plain. The solid dairy manure trial included control without N fertilization (CK), inorganic N fertilizer (SNPK), and fresh (RAW) and composted (COM) dairy manure. The liquid dairy effluent trial consisted of control without N fertilization (CF), inorganic N fertilizer (ENPK), and fresh (FDE) and stored (SDE) dairy effluent. The N application rate was 225kgNha -1 for inorganic N fertilizer, dairy manure, and effluent treatments in both seasons. Annual N leaching loss (ANLL) was highest in SNPK (53.02 and 16.21kgNha -1 in 2013/2014 and 2014/2015, respectively), which were 1.65- and 2.04-fold that of COM, and 1.59- and 1.26-fold that of RAW. In the effluent trial (2014/2015), ANLL for ENPK and SDE (16.22 and 16.86kgNha -1 , respectively) were significantly higher than CF and FDE (6.3 and 13.21kgNha -1 , respectively). NO 3 - contributed the most (34-92%) to total N leaching loss among all treatments, followed by dissolved organic N (14-57%). COM showed the lowest N leaching loss due to a reduction in NO 3 - loss. Yield-scaled N leaching in COM (0.35kgNMg -1 silage) was significantly (Pleaching loss while ensuring high crop yield in the North China Plain. Copyright © 2017 Elsevier B.V. All rights reserved.

Inorganic and organic nitrogen acquisition by a fern Dicranopteris dichotoma in a subtropical forest in South China.

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Xingliang Xu

Full Text Available The fern Dicranopteris dichotoma is an important pioneer species of the understory in Masson pine (Pinus massoniana forests growing on acidic soils in the subtropical and tropical China. To improve our understanding of the role of D. dichotoma in nitrogen (N uptake of these forests, a short-term (15N experiment was conducted at mountain ridge (MR, with low N level and mountain foot (MF, with high N level. We injected (15N tracers as (15NH4, (15NO3 or (15N-glycine into the soil surrounding each plant at both MR and MF sites. Three hours after tracer injection, the fern D. dichotoma took up 15NH4+ significantly faster at MF than at MR, but it showed significantly slower uptake of (15NO3- at MF than at MR. Consequently, (15NO3- made greater contribution to the total N uptake (50% to the total N uptake at MR than at MF, but (15N-glycine only contributed around 11% at both sites. Twenty-four hours after tracer injection, D. dichotoma preferred (15NH4+ (63% at MR, whereas it preferred (15NO3- (47% at MF. We concluded that the D. dichotoma responds distinctly in its uptake pattern for three available N species over temporal and spatial scales, but mainly relies on inorganic N species in the subtropical forest. This suggests that the fern employs different strategies to acquire available N which depends on N levels and time.

Comparative changes in monthly blood urea nitrogen, total protein ...

African Journals Online (AJOL)

The objective of this study was to determine the comparative changes in the monthly blood urea nitrogen (BUN) concentration, total protein (TP) concentration in blood serum and the body condition score of Nguni cows and heifers raised on sweetveld. Twenty-four clinically healthy animals in different parities, namely Parity ...

Dissolved organic nitrogen recalcitrance and bioavailable nitrogen quantification for effluents from advanced nitrogen removal wastewater treatment facilities

International Nuclear Information System (INIS)

Fan, Lu; Brett, Michael T.; Jiang, Wenju; Li, Bo

2017-01-01

The objective of this study was to determine the composition of nitrogen (N) in the effluents of advanced N removal (ANR) wastewater treatment plants (WWTPs). This study also tested two different experimental protocols for determining dissolved N recalcitrance. An analysis of 15 effluent samples from five WWTPs, showed effluent concentrations and especially effluent composition varied greatly from one system to the other, with total nitrogen (TN) ranging between 1.05 and 8.10 mg L −1 . Nitrate (NO 3 − ) accounted for between 38 ± 32% of TN, and ammonium accounted for a further 29 ± 28%. All of these samples were dominated by dissolved inorganic nitrogen (DIN; NO 3 −  + NH 4 + ), and uptake experiments indicated the DIN fraction was as expected highly bioavailable. Dissolved organic N (DON) accounted for 20 ± 11% for the total dissolved N in these effluents, and uptake experiments indicated the bioavailability of this fraction varied between 27 ± 26% depending on the WWTP assessed. These results indicate near complete DIN removal should be the primary goal of ANR treatment systems. The comparison of bioavailable nitrogen (BAN) quantification protocols showed that the dissolved nitrogen uptake bioassay approach was clearly a more reliable way to determine BAN concentrations compared to the conventional cell yield protocol. Moreover, because the nitrogen uptake experiment was much more sensitive, this protocol made it easier to detect extrinsic factors (such as biological contamination or toxicity) that could affect the accuracy of these bioassays. Based on these results, we recommend the nitrogen uptake bioassay using filtered and autoclaved samples to quantify BAN concentrations. However, for effluent samples indicating toxicity, algal bioassays will not accurately quantify BAN. - Highlights: • DIN was the dominated N pool for most of the tested effluent samples. • DON bioavailability considerably varied depending on the WWTP assessed. �

[Effects of two submerged macrophytes on dissolved inorganic nitrogen in overlying water and interstitial water].

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Yang, Wen-Bin; Li, Yang; Sun, Gong-Xian

2014-06-01

Ceratophyllum demersum (C. demersum) and Vallisneria spiralis L. (V. spiralis L.) were studied as model submerged macrophytes. The effects of the submerged macrophytes on the forms and concentration of the dissolved inorganic nitrogen (DIN) in the overlying water and the interstitial water, as well as the diffusion flux of DIN in the water-sediment interface were investigated by batch simulation experiment. The results indicated that the removal effect of DIN in the overlying water was better than that in the interstitial water by submerged macrophytes. The removal efficiency of DIN in the overlying water and the interstitial water followed the order of NO2(-) -N > NH4(+) -N > NO3(-) -N. The removal rate of DIN by C. demersum was higher than that of V. spiralis L. in the overlying water, while the result was converse in the interstitial water. C. demersum and V. spiralis L. decreased the diffusion flux of NH4(+) -N and NO2(-) -N, and increased the diffusion flux of NO3(-) -N significantly. Consequently, NO3(-) -N replaced NH4(+) -N and became the main form of DIN, which diffused from the interstitial water to the overlying water. The impact of the diffusion flux of NO3(-) -N between C. demersum and V. spiralis L. showed no significant difference, and the result was the same for NH4(+) -N. C. demersum and V. spiralis L. increased the width of variation of the three nitrogen forms to total DIN in the overlying water and the interstitial water, the influence on the ratio of DIN by C. demersum was greater than that of V. spiralis L. in the overlying water, while the result was opposite in the interstitial water. In general, C. demersum had more influence in the overlying water, while V. spiralis L. had more influence in the interstitial water, and the influence of DIN diffusion flux was not significant.

Estimating Soil Bulk Density and Total Nitrogen from Catchment ...

African Journals Online (AJOL)

Even though data on soil bulk density (BD) and total nitrogen (TN) are essential for planning modern farming techniques, their data availability is limited for many applications in the developing word. This study is designed to estimate BD and TN from soil properties, land-use systems, soil types and landforms in the ...

Determination of dietary intake of total arsenic, inorganic arsenic and total mercury in the Chilean school meal program.

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Bastías, J M; Bermúdez, M; Carrasco, J; Espinoza, O; Muñoz, M; Galotto, M J; Muñoz, O

2010-10-01

The dietary intake of total arsenic (tAs), inorganic arsenic (iAs) and total mercury (tHg) in lunch and breakfast servings provided by the Chilean School Meal Program (SMP) was estimated, using the duplicate-portion variant of the total diet study. Lunch and breakfast samples were collected from 65 schools throughout the country in 2006. The population sample was a group of girls and boys between 6 and 18 years old. The tAs concentration was measured via hydride-generation atomic absorption spectrometry. The total mercury concentration was measured via cold-vapor atomic absorption spectroscopy. The estimated iAs intake was 12.5% (5.4 μg/day) of the Provisional tolerable daily intake (PTDI) as proposed by the FAO/WHO, and the tHg intake was 13.2% (1.9 μg/day) of the PTDI as proposed by the FAO/WHO. It was therefore concluded that tAs, iAs and tHg intake from food provided by the SMP do not pose risks to student health.

Nitrogen removal in a SBR operated with and without pre-denitrification: effect of the carbon:nitrogen ratio and the cycle time.

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Mees, Juliana Bortoli Rodrigues; Gomes, Simone Damasceno; Hasan, Salah Din Mahmud; Gomes, Benedito Martins; Boas, Márcio Antonio Vilas

2014-01-01

The effects of cycle time (CT) (8, 12 and 16h) and C/N ratio (3, 6 and 9) on nitrogen removal efficiencies in a bench top sequencing batch reactor treating slaughterhouse wastewater were investigated under different operating conditions: in condition 1, the reaction comprises an aerobic/anoxic phase and in condition II, the reaction comprises anoxic I/aerobic/anoxic II phases (with pre-denitrification). The greatest percentages of nitrogen removal were obtained in the CT range from 12 to 16 h and C/N ratios from 3 to 6, with mean efficiency values of 80.76% and 85.57% in condition I and 90.99% and 91.09% in condition II. Although condition II gave a higher removal of total inorganic nitrogen (NH4+ - N + NO2- - N + NO3- - N) than condition I, only condition I showed statistically significant and predictive regression for all the steps of nitrogen removal.

Effect of nitrogen sources on the biodegradation of diesel fuel in unsaturated soil

International Nuclear Information System (INIS)

Brook, T. R.; Stiver, W. H.; Zytner, R. G.

1997-01-01

The various factors involved in controlling the rate and efficiency of the bioremediation process were studied, among them the type and concentration of contaminants, temperature, oxygen content and nutrient status. This study emphasized the effect of the nitrogen source on the degradation rate of diesel fuel in nutrient-limited soil. Various nitrogen sources were studied, including ammonium nitrate, urea, and urea oligomers. Treatment with urea produced the highest rate of hydrocarbon degradation, but ammonium levels were a better indicator of nutrient performance than total inorganic nitrogen. Other nitrogen sources produced little or no effect on the rate of biodegradation; there was no evidence that nitrate at 0.5 mg N/g concentration was inhibitory. 11 refs., 6 figs

Response of food organisms to inorganic nitrogen availability ...

African Journals Online (AJOL)

Influence of inorganic N2 forms on pond food organisms was investigated. Seven identified plankton taxa comprising four phytoplankton: Desmidiaceae (desmids), Bacillariophyceae (diatoms), Cyanophyceae (blue-green algae) and Chlorophyceae (green algae) and three zooplankton: Protozoa, Cladocera and Rotifera ...

Total arsenic in selected food samples from Argentina: Estimation of their contribution to inorganic arsenic dietary intake.

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Sigrist, Mirna; Hilbe, Nandi; Brusa, Lucila; Campagnoli, Darío; Beldoménico, Horacio

2016-11-01

An optimized flow injection hydride generation atomic absorption spectroscopy (FI-HGAAS) method was used to determine total arsenic in selected food samples (beef, chicken, fish, milk, cheese, egg, rice, rice-based products, wheat flour, corn flour, oats, breakfast cereals, legumes and potatoes) and to estimate their contributions to inorganic arsenic dietary intake. The limit of detection (LOD) and limit of quantification (LOQ) values obtained were 6μgkg(-)(1) and 18μgkg(-)(1), respectively. The mean recovery range obtained for all food at a fortification level of 200μgkg(-)(1) was 85-110%. Accuracy was evaluated using dogfish liver certified reference material (DOLT-3 NRC) for trace metals. The highest total arsenic concentrations (in μgkg(-)(1)) were found in fish (152-439), rice (87-316) and rice-based products (52-201). The contribution to inorganic arsenic (i-As) intake was calculated from the mean i-As content of each food (calculated by applying conversion factors to total arsenic data) and the mean consumption per day. The primary contributors to inorganic arsenic intake were wheat flour, including its proportion in wheat flour-based products (breads, pasta and cookies), followed by rice; both foods account for close to 53% and 17% of the intake, respectively. The i-As dietary intake, estimated as 10.7μgday(-)(1), was significantly lower than that from drinking water in vast regions of Argentina. Copyright © 2016 Elsevier Ltd. All rights reserved.

Statistically extracted fundamental watershed variables for estimating the loads of total nitrogen in small streams

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Kronholm, Scott C.; Capel, Paul D.; Terziotti, Silvia

2016-01-01

Accurate estimation of total nitrogen loads is essential for evaluating conditions in the aquatic environment. Extrapolation of estimates beyond measured streams will greatly expand our understanding of total nitrogen loading to streams. Recursive partitioning and random forest regression were used to assess 85 geospatial, environmental, and watershed variables across 636 small (monitoring may be beneficial.

Long-term ecosystem nitrogen storage and soil nitrogen availability in post-fire lodgepole pine ecosystems

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Erica A. H. Smithwick; Daniel M. Kashian; Michael G. Ryan; Monica G.  Turner

2009-01-01

Long-term, landscape patterns in inorganic nitrogen (N) availability and N stocks following infrequent, stand-replacing fire are unknown but are important for interpreting the effect of disturbances on ecosystem function. Here, we present results from a replicated chronosequence study in the Greater Yellowstone Ecosystem (Wyoming, USA) directed at measuring inorganic N...

TILLAGE AND DYNAMICS OF INORGANIC NITROGEN IN ECOLOGICAL AND INTEGRATION MANAGEMENT SYSTEMS

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J SMATANA

2002-05-01

Full Text Available During the period of 1991-1993 in the field experiment, the effect of different soil management (tillage 0,24 m and tillage 0,12-0,15 m in ecological and integration management system on changes of inorganic nitrogen (Nan = N-NH4 + + N-NO3 - content in the soil layer from 0 up to 0,6 m of the soil depth (0,00-0,30 m and 0,30- 0,60 m were studied. Trials were held in a warm climatic zone of the South – Western Slovakia on the brown soil. Different soil management systems (tillage 0,24 m and tillage 0,12-0,15 m considerably did not affected ammonification and nitrification processes in the soil. The sustainability of minimalization via shallow ploughing is not excluded, on the contrary this minimalization may have high a positive influence on economic saving the energy, labour costs, etc. The quantitative and qualitative changes of studied form of N were significantly effected by weather and soil depth. Soil content of N-NH4 + and N-NO3 - was in negative correlation with soil depth.

Concentration and flux of total and dissolved phosphorus, total nitrogen, chloride, and total suspended solids for monitored tributaries of Lake Champlain, 1990-2012

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Medalie, Laura

2014-01-01

Annual and daily concentrations and fluxes of total and dissolved phosphorus, total nitrogen, chloride, and total suspended solids were estimated for 18 monitored tributaries to Lake Champlain by using the Weighted Regressions on Time, Discharge, and Seasons regression model. Estimates were made for 21 or 23 years, depending on data availability, for the purpose of providing timely and accessible summary reports as stipulated in the 2010 update to the Lake Champlain “Opportunities for Action” management plan. Estimates of concentration and flux were provided for each tributary based on (1) observed daily discharges and (2) a flow-normalizing procedure, which removed the random fluctuations of climate-related variability. The flux bias statistic, an indicator of the ability of the Weighted Regressions on Time, Discharge, and Season regression models to provide accurate representations of flux, showed acceptable bias (less than ±10 percent) for 68 out of 72 models for total and dissolved phosphorus, total nitrogen, and chloride. Six out of 18 models for total suspended solids had moderate bias (between 10 and 30 percent), an expected result given the frequently nonlinear relation between total suspended solids and discharge. One model for total suspended solids with a very high bias was influenced by a single extreme value; however, removal of that value, although reducing the bias substantially, had little effect on annual fluxes.

Nitrogen kinetics in aquatic plants in arctic Alaska

International Nuclear Information System (INIS)

McRoy, C.P.; Alexander, V.

1975-01-01

The kinetics of nitrogen in terms of ammonia uptake was measured for Carex aquatilis in arctic tundra ponds using 15 N tracer techniques. Nitrogen content of the leaves and primary productivity were measured throughout a growing season. The maximum uptake velocity for ammonia was 2.75 x 10 -2 % N/g dry weight per h with a Ksub(t) of 8.4-12.5 μgatoms/l. A second estimate of nitrogen uptake was made from the increase in nitrogen content throughout the season and from this a rate of 1.85 x 10 -2 % N/g dry weight per day was obtained for Carex aquatilis and 3.6 x 10 -2 % N/g dry weight per day for Arctophylla fulva. The total nitrogen concentration in the leaves was closely related to productivity, possible providing a new approach to productivity measurements for emergent vascular plants. Emergent vascular plants absorb ammonia across and translocate it to all portions of the plant. The ecological significance of this is considerable, since in many waters inorganic nitrogen content of sediment is much higher than that of the water surrounding the leaves and stems, and can provide a source of nitrogen

Elevational Variation in Soil Amino Acid and Inorganic Nitrogen Concentrations in Taibai Mountain, China.

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Xiaochuang Cao

Full Text Available Amino acids are important sources of soil organic nitrogen (N, which is essential for plant nutrition, but detailed information about which amino acids predominant and whether amino acid composition varies with elevation is lacking. In this study, we hypothesized that the concentrations of amino acids in soil would increase and their composition would vary along the elevational gradient of Taibai Mountain, as plant-derived organic matter accumulated and N mineralization and microbial immobilization of amino acids slowed with reduced soil temperature. Results showed that the concentrations of soil extractable total N, extractable organic N and amino acids significantly increased with elevation due to the accumulation of soil organic matter and the greater N content. Soil extractable organic N concentration was significantly greater than that of the extractable inorganic N (NO3--N + NH4+-N. On average, soil adsorbed amino acid concentration was approximately 5-fold greater than that of the free amino acids, which indicates that adsorbed amino acids extracted with the strong salt solution likely represent a potential source for the replenishment of free amino acids. We found no appreciable evidence to suggest that amino acids with simple molecular structure were dominant at low elevations, whereas amino acids with high molecular weight and complex aromatic structure dominated the high elevations. Across the elevational gradient, the amino acid pool was dominated by alanine, aspartic acid, glycine, glutamic acid, histidine, serine and threonine. These seven amino acids accounted for approximately 68.9% of the total hydrolyzable amino acid pool. The proportions of isoleucine, tyrosine and methionine varied with elevation, while soil major amino acid composition (including alanine, arginine, aspartic acid, glycine, histidine, leucine, phenylalanine, serine, threonine and valine did not vary appreciably with elevation (p>0.10. The compositional

The efficacy of winter cover crops to stabilize soil inorganic nitrogen after fall-applied anhydrous ammonia.

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Lacey, Corey; Armstrong, Shalamar

2015-03-01

There is a dearth of knowledge on the ability of cover crops to increase the effectiveness of fall-applied nitrogen (N). The objective of this study was to investigate the efficacy of two cover crop species to stabilize inorganic soil N after a fall application of N. Fall N was applied at a rate of 200 kg N ha into living stands of cereal rye, tillage radish, and a control (no cover crop) at the Illinois State University Research and Teaching Farm in Lexington, Illinois. Cover crops were sampled to determine N uptake, and soil samples were collected in the spring at four depths to 80 cm to determine the distribution of inorganic N within the soil profile. Tillage radish (131.9-226.8 kg ha) and cereal rye (188.1-249.9 kg ha N) demonstrated the capacity to absorb a minimum of 60 to 80% of the equivalent rate of fall-applied N, respectively. Fall applying N without cover crops resulted in a greater percentage of soil NO-N (40%) in the 50- to 80-cm depth, compared with only 31 and 27% when tillage radish and cereal rye were present at N application. At planting, tillage radish stabilized an average of 91% of the equivalent rate of fall-applied N within the 0- to 20-cm, depth compared with 66 and 57% for the cereal rye and control treatments, respectively. This study has demonstrated that fall applying N into a living cover crop stand has the potential to reduce the vulnerability of soil nitrate and to stabilize a greater concentration of inorganic N within the agronomic depths of soil. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Determination of inorganic mercury and total mercury in biological and environmental samples by flow injection-cold vapor-atomic absorption spectrometry using sodium borohydride as the sole reducing agent

International Nuclear Information System (INIS)

Rio Segade, Susana; Tyson, Julian F.

2003-01-01

A simple, fast, precise and accurate method to determine inorganic mercury and total mercury in biological and environmental samples was developed. The optimized flow-injection mercury system permitted the separate determination of inorganic mercury and total mercury using sodium borohydride as reducing agent. Inorganic mercury was selectively determined after reduction with 10 -4 % w/v sodium borohydride, while total mercury was determined after reduction with 0.75% w/v sodium borohydride. The calibration graphs were linear up to 30 ng ml -1 . The detection limits of the method based on three times the standard deviation of the blank were 24 and 3.9 ng l -1 for total mercury and inorganic mercury determination, respectively. The relative standard deviation was less than 1.5% for a 10 ng ml -1 mercury standard. As a means of checking method performance, deionized water and pond water samples were spiked with methylmercury and inorganic mercury; quantitative recovery for total mercury and inorganic mercury was obtained. The accuracy of the method was verified by analyzing alkaline and acid extracts of five biological and sediment reference materials. Microwave-assisted extraction procedures resulted in higher concentrations of recovered mercury species, lower matrix interference with mercury determination and less time involved in sample treatment than conventional extraction procedures. The standard addition method was only needed for calibration when biological samples were analyzed. The detection limits were in the range of 1.2-19 and 6.6-18 ng g -1 in biological and sediment samples for inorganic mercury and total mercury determination, respectively

Total mineral material, acidity, sulphur, and nitrogen in rain and snow at Kentville, Nova Scotia

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Herman, F A; Gorham, E

1957-01-01

Analyses of total ash, sulphur, ph, ammonia, and nitrate nitrogen have been made on 23 monthly precipitation samples and 17 individual snow samples collected between June 1952 and May 1954 at Kentville, Nova Scotia, in a predominantly agricultural area. Mean annual supply of total mineral ash was 95 kg/ha, of sulphur 9.1 hg/ha, of ammonia nitrogen 2.8 kg/ha, and of nitrate nitrogen 1.1 kg/ha. Average pH was 5.7, and rains more acid than this exhibited higher levels of both nitrate and sulphur, and a marked correlation between the latter and ammonia. Snow samples had much lower concentrations of ash, sulphur, and nitrogen than rain samples collected in the same months, which may perhaps indicate a lower efficiency of snow flakes in removing materials from the atmosphere.

Year-round atmospheric wet and dry deposition of nitrogen and phosphorus on water and land surfaces in Nanjing, China.

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Sun, Liying; Li, Bo; Ma, Yuchun; Wang, Jinyang; Xiong, Zhengqin

2013-06-01

The dry deposition of ammonium, nitrate, and total phosphorus (TP) to both water (DW) and land (DD) surfaces, along with wet deposition, were simultaneously monitored from March 2009 to February 2011 in Nanjing, China. Results showed that wet deposition of total phosphorus was 1.1 kg phosphorus ha (-1)yr(-1), and inorganic nitrogen was 28.7 kg nitrogen ha (-1)yr(-1), with 43% being ammonium nitrogen. Dry deposition of ammonium, nitrate, and total phosphorus, measured by the DW/DD method, was 7.5/2.2 kg nitrogen ha (-1)yr(-1), 6.3/ 4.9 kg nitrogen ha (-1)yr(-1), and 1.9/0.4 kg phosphorus ha (-1)yr(-1), respectively. Significant differences between the DW and DD methods indicated that both methods should be employed simultaneously when analyzing deposition to aquatic and terrestrial ecosystems in watershed areas. The dry deposition of ammonium, nitrate, and total phosphorus contributed 38%, 28%, and 63%, respectively, to the total deposition in the simulated aquatic ecosystem; this has significance for the field of water eutrophication control.

Influence of sulfur and nitrogen supply on the susceptibility of Pisum sativum to SO/sub 2/

Energy Technology Data Exchange (ETDEWEB)

Klein, H; Jaeger, H J; Steubing, L

1974-01-01

The susceptibility of Pisum to SO/sub 2/ injury was examined in relation to the sulfur and nitrogen nutrition. The injury was measured by comparing the dry matter yield to control and treated plants. SO/sub 2/ effects on metabolism were established by determining the content of organic and inorganic sulfur and, indirectly, by measuring total nitrogen, amino acid nitrogen, and protein nitrogen. The plants grown in nutrient solutions deficient in sulfur or nitrogen showed a decreased sensitivity to SO/sub 2/ pollution compared to the control. The higher content of amino acid nitrogen and organic sulfur of the plants grown in a nitrogen-deficient solution suggests that an increased synthesis of sulfur containing amino acids occurs. The slighter injury of the plants deficient in sulfur may be explained by the delayed sulfur supply.

Free amino nitrogen concentration correlates to total yeast assimilable nitrogen concentration in apple juice.

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Boudreau, Thomas F; Peck, Gregory M; O'Keefe, Sean F; Stewart, Amanda C

2018-01-01

Yeast assimilable nitrogen (YAN) is essential for yeast growth and metabolism during apple ( Malus x domestica Borkh.) cider fermentation. YAN concentration and composition can impact cider fermentation kinetics and the formation of volatile aroma compounds by yeast. The YAN concentration and composition of apples grown in Virginia, USA over the course of two seasons was determined through analysis of both free amino nitrogen (FAN) and ammonium ion concentration. FAN was the largest fraction of YAN, with a mean value of 51 mg N L -1 FAN compared to 9 mg N L -1 ammonium. Observed YAN values ranged from nine to 249 mg N L -1 , with a mean value of 59 mg N L -1 . Ninety-four percent of all samples analyzed in this study contained yeast to fully utilize all of the fermentable sugars. FAN concentration was correlated with total YAN concentration, but ammonium concentration was not. Likewise, there was no correlation between FAN and ammonium concentration.

Vertical distribution of total carbon, nitrogen and phosphorus in sediments of Drug Spring Lake, Wudalianchi

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Zeng, Ying; Yang, Chen

2018-02-01

The content of total organic carbon, total nitrogen and total phosphorus in sediments of Drug Spring Lake was detected and their vertical distribution characteristic was analysed. Results showed that there were significant changes to the content of total organic carbon, total nitrogen and total phosphorus in different depth of the columnar sediments. Their highest content both appeared in the interval of 10cm to 25cm corresponding to the period of 1980s to 1990s, when the tourism of Wudalianchi scenic area began to develop. It reflected the impact of human activities on the Drug Spring Lake. That means the regulation was still not enough, although a series of pollution control measures adopted by the government in recent years had initial success.

In vivo Prompt Gamma Neutron Activation Analysis Facility for Total Body Nitrogen and Cd

International Nuclear Information System (INIS)

Munive, Marco; Revilla, Angel; Solis, Jose L.

2007-01-01

A Prompt Gamma Neutron Activation Analysis (PGNAA) system has been designed and constructed to measure the total body nitrogen and Cd for in vivo studies. An aqueous solution of KNO 3 was used as phantom for system calibration. The facility has been used to monitor total body nitrogen (TBN) of mice and found that is related to their diet. Some mice swallowed diluted water with Cl 2 Cd, and the presence of Cd was detected in the animals. The minimum Cd concentration that the system can detect was 20 ppm

Nitrogen inputs by precipitation in the Nigerian Savanna | Adeniyi ...

African Journals Online (AJOL)

Inorganic nitrogen input via direct bulk precipitation was measured, and the relation between the different nitrogen species and rainfall characteristics determined over three rainy seasons at Shagunu, a remote, sparsely populated, non-industrialized site in the northern Guinea savanna of Nigeria. Nitrogen concentration per ...

Comparing carbon to carbon: Organic and inorganic carbon balances across nitrogen fertilization gradients in rainfed vs. irrigated Midwest US cropland

Science.gov (United States)

Hamilton, S. K.; McGill, B.

2017-12-01

The top meter of the earth's soil contains about twice the amount of carbon than the atmosphere. Agricultural management practices influence whether a cropland soil is a net carbon source or sink. These practices affect both organic and inorganic carbon cycling although the vast majority of studies examine the former. We will present results from several rarely-compared carbon fluxes: carbon dioxide emissions and sequestration from lime (calcium carbonate) weathering, dissolved gases emitted from groundwater-fed irrigation, dissolved organic carbon (DOC) leaching to groundwater, and soil organic matter storage. These were compared in a corn-soybean-wheat rotation under no-till management across a nitrogen fertilizer gradient where half of the replicated blocks are irrigated with groundwater. DOC and liming fluxes are also estimated from a complementary study in neighboring plots comparing a gradient of management practices from conventional to biologically-based annuals and perennials. These studies were conducted at the Kellogg Biological Station Long Term Ecological Research site in Michigan where previous work estimated that carbon dioxide emissions from liming accounted for about one quarter of the total global warming impact (GWI) from no-till systems—our work refines that figure. We will present a first time look at the GWI of gases dissolved in groundwater that are emitted when the water equilibrates with the atmosphere. We will explore whether nitrogen fertilizer and irrigation increase soil organic carbon sequestration by producing greater crop biomass and residues or if they enhance microbial activity, increasing decomposition of organic matter. These results are critical for more accurately estimating how intensive agricultural practices affect the carbon balance of cropping systems.

Wet and Dry Atmospheric Depositions of Inorganic Nitrogen during Plant Growing Season in the Coastal Zone of Yellow River Delta

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Junbao Yu

2014-01-01

Full Text Available The ecological problems caused by dry and wet deposition of atmospheric nitrogen have been widespread concern in the world. In this study, wet and dry atmospheric depositions were monitored in plant growing season in the coastal zone of the Yellow River Delta (YRD using automatic sampling equipment. The results showed that SO42- and Na+ were the predominant anion and cation, respectively, in both wet and dry atmospheric depositions. The total atmospheric nitrogen deposition was ~2264.24 mg m−2, in which dry atmospheric nitrogen deposition was about 32.02%. The highest values of dry and wet atmospheric nitrogen deposition appeared in May and August, respectively. In the studied area, NO3-–N was the main nitrogen form in dry deposition, while the predominant nitrogen in wet atmospheric deposition was NH4+–N with ~56.51% of total wet atmospheric nitrogen deposition. The average monthly attribution rate of atmospheric deposition of NO3-–N and NH4+–N was ~31.38% and ~20.50% for the contents of NO3-–N and NH4+–N in 0–10 cm soil layer, respectively, suggested that the atmospheric nitrogen was one of main sources for soil nitrogen in coastal zone of the YRD.

Wet and dry atmospheric depositions of inorganic nitrogen during plant growing season in the coastal zone of Yellow River Delta.

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Yu, Junbao; Ning, Kai; Li, Yunzhao; Du, Siyao; Han, Guangxuan; Xing, Qinghui; Wu, Huifeng; Wang, Guangmei; Gao, Yongjun

2014-01-01

The ecological problems caused by dry and wet deposition of atmospheric nitrogen have been widespread concern in the world. In this study, wet and dry atmospheric depositions were monitored in plant growing season in the coastal zone of the Yellow River Delta (YRD) using automatic sampling equipment. The results showed that SO4 (2-) and Na(+) were the predominant anion and cation, respectively, in both wet and dry atmospheric depositions. The total atmospheric nitrogen deposition was ~2264.24 mg m(-2), in which dry atmospheric nitrogen deposition was about 32.02%. The highest values of dry and wet atmospheric nitrogen deposition appeared in May and August, respectively. In the studied area, NO3 (-)-N was the main nitrogen form in dry deposition, while the predominant nitrogen in wet atmospheric deposition was NH4 (+)-N with ~56.51% of total wet atmospheric nitrogen deposition. The average monthly attribution rate of atmospheric deposition of NO3 (-)-N and NH4 (+)-N was ~31.38% and ~20.50% for the contents of NO3 (-)-N and NH4 (+)-N in 0-10 cm soil layer, respectively, suggested that the atmospheric nitrogen was one of main sources for soil nitrogen in coastal zone of the YRD.

Stable nitrogen isotopes in coastal macroalgae: geographic and anthropogenic variability.

Science.gov (United States)

Viana, Inés G; Bode, Antonio

2013-01-15

Growing human population adds to the natural nitrogen loads to coastal waters. Both anthropogenic and natural nitrogen is readily incorporated in new biomass, and these different nitrogen sources may be traced by the measurement of the ratio of stable nitrogen isotopes (δ(15)N). In this study δ(15)N was determined in two species of macroalgae (Ascophyllum nodosum and Fucus vesiculosus), and in nitrate and ammonium to determine the relative importance of anthropogenic versus natural sources of nitrogen along the coast of NW Spain. Both algal species and nitrogen sources showed similar isotopic enrichment for a given site, but algal δ(15)N was not related to either inorganic nitrogen concentrations or δ(15)N in the water samples. The latter suggests that inorganic nitrogen inputs are variable and do not always leave an isotopic trace in macroalgae. However, a significant linear decrease in macroalgal δ(15)N along the coast is consistent with the differential effect of upwelling. Besides this geographic variability, the influence of anthropogenic nitrogen sources is evidenced by higher δ(15)N in macroalgae from rias and estuaries compared to those from open coastal areas and in areas with more than 15×10(3) inhabitants in the watershed. These results indicate that, in contrast with other studies, macroalgal δ(15)N is not simply related to either inorganic nitrogen concentrations or human population size but depends on other factors as the upwelling or the efficiency of local waste treatment systems. Copyright © 2012 Elsevier B.V. All rights reserved.

Annual reports in inorganic and general syntheses 1973

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Niedenzu, Kurt

1974-01-01

Annual Reports in Inorganic and General Syntheses-1973 presents an organized annual summary of synthetic developments in inorganic chemistry and its related areas. The book covers the synthetic aspects and structural or mechanistic features of elements, including the main group hydrides, alkali and alkaline earth elements, boron, aluminium, gallium, indium, thallium, silicon, germanium, tin, and lead, nitrogen, phosphorus, arsenic, antimony, bismuth, chalcogens, halogens and pseudohalogens, and noble gases. The text also discusses the synthetic aspects and structural or mechanistic features of

Atmospheric nitrogen deposition budget in a subtropical hydroelectric reservoir (Nam Theun II case study, Lao PDR)

Science.gov (United States)

Adon, Marcellin; Galy-Lacaux, Corinne; Serça, Dominique; Guerin, Frederic; Guedant, Pierre; Vonghamsao, Axay; Rode, Wanidaporn

2016-04-01

With 490 km² at full level of operation, Nam Theun 2 (NT2) is one of the largest hydro-reservoir in South East Asia. NT2 is a trans-basin hydropower project that diverts water from the Nam Theun river (a Mekong tributary) to the Xe Ban Fai river (another Mekong tributary). Atmospheric deposition is an important source of nitrogen (N), and it has been shown that excessive fluxes of N from the atmosphere has resulted in eutrophication of many coastal waters. A large fraction of atmospheric N input is in the form of inorganic N. This study presents an estimation of the atmospheric inorganic nitrogen budget into the NT2 hydroelectric reservoir based on a two-year monitoring (July 2010 to July 2012) including gas concentrations and precipitation. Dry deposition fluxes are calculated from monthly mean surface measurements of NH3, HNO3 and NO2 concentrations (passive samplers) together with simulated deposition velocities, and wet deposition fluxes from NH4+ and NO3- concentrations in single event rain samples (automated rain sampler). Annual rainfall amount was 2500 and 3160 mm for the two years. The average nitrogen deposition flux is estimated at 1.13 kgN.ha-1.yr-1 from dry processes and 5.52 kgN.ha-1.yr-1 from wet ones, i.e., an average annual total nitrogen flux of 6.6 kgN.ha-1.yr-1 deposited into the NT2 reservoir. The wet deposition contributes to 83% of the total N deposition. The nitrogen deposition budget has been also calculated over the rain tropical forest surrounding the reservoir. Due to higher dry deposition velocities above forested ecosystems, gaseous dry deposition flux is estimated at 4.0 kgN.ha-1.yr-1 leading to a total nitrogen deposition about 9.5 kgN.ha-1.yr-1. This result will be compared to nitrogen deposition in the African equatorial forested ecosystems in the framework of the IDAF program (IGAC-DEBITS-AFrica).

Estimation of Total Nitrogen and Phosphorus in New England Streams Using Spatially Referenced Regression Models

Science.gov (United States)

Moore, Richard Bridge; Johnston, Craig M.; Robinson, Keith W.; Deacon, Jeffrey R.

2004-01-01

The U.S. Geological Survey (USGS), in cooperation with the U.S. Environmental Protection Agency (USEPA) and the New England Interstate Water Pollution Control Commission (NEIWPCC), has developed a water-quality model, called SPARROW (Spatially Referenced Regressions on Watershed Attributes), to assist in regional total maximum daily load (TMDL) and nutrient-criteria activities in New England. SPARROW is a spatially detailed, statistical model that uses regression equations to relate total nitrogen and phosphorus (nutrient) stream loads to nutrient sources and watershed characteristics. The statistical relations in these equations are then used to predict nutrient loads in unmonitored streams. The New England SPARROW models are built using a hydrologic network of 42,000 stream reaches and associated watersheds. Watershed boundaries are defined for each stream reach in the network through the use of a digital elevation model and existing digitized watershed divides. Nutrient source data is from permitted wastewater discharge data from USEPA's Permit Compliance System (PCS), various land-use sources, and atmospheric deposition. Physical watershed characteristics include drainage area, land use, streamflow, time-of-travel, stream density, percent wetlands, slope of the land surface, and soil permeability. The New England SPARROW models for total nitrogen and total phosphorus have R-squared values of 0.95 and 0.94, with mean square errors of 0.16 and 0.23, respectively. Variables that were statistically significant in the total nitrogen model include permitted municipal-wastewater discharges, atmospheric deposition, agricultural area, and developed land area. Total nitrogen stream-loss rates were significant only in streams with average annual flows less than or equal to 2.83 cubic meters per second. In streams larger than this, there is nondetectable in-stream loss of annual total nitrogen in New England. Variables that were statistically significant in the total

Measurement of total-body oxygen, nitrogen, and carbon in vivo by photon activation analysis

International Nuclear Information System (INIS)

Ulin, K.

1984-01-01

With the aim of assessing nutritional status, the feasibility of measuring the total body quantities of the major body elements, i.e. oxygen, nitrogen, and carbon, using the photon beam of a 45 MV betatron and a whole-body counter, has been evaluated in detail. Following photon activation a single energy γ-radiation (.511 MeV) is observed from all three elements to be measured. The half-lives of 15 O, 13 N, and 11 C, however, are sufficiently different (20.5 min, 10.0 min, and 20.4 min. respectively) to permit their measurement from an analysis of the measured decay curve. Following corrections for interfering reactions, a computer curve-fitting algorithm is used to resolve the data into 15 O, 13 N, and 11 C components. Measurements of O, N, and C have been made both in phantoms and in live and dead rats. A comparison of the body composition results from this technique with results from chemical analysis indicates that measured carbon can quite accurately predict total body fat. The comparison of the total body nitrogen measurement by photon activation with total body protein by chemical analysis was inconclusive and suggests that further work be done to verify the estimated accuracy of the nitrogen measurement

Operational strategies for nitrogen removal in granular sequencing batch reactor

International Nuclear Information System (INIS)

Chen, Fang-yuan; Liu, Yong-Qiang; Tay, Joo-Hwa; Ning, Ping

2011-01-01

This study investigated the effects of different operational strategies for nitrogen removal by aerobic granules with mean granule sizes of 1.5 mm and 0.7 mm in a sequencing batch reactor (SBR). With an alternating anoxic/oxic (AO) operation mode without control of dissolve oxygen (DO), the granular sludge with different size achieved the total inorganic nitrogen (TIN) removal efficiencies of 67.8-71.5%. While under the AO condition with DO controlled at 2 mg/l at the oxic phase, the TIN removal efficiency was improved up to 75.0-80.4%. A novel operational strategy of alternating anoxic/oxic combined with the step-feeding mode was developed for nitrogen removal by aerobic granules. It was found that nitrogen removal efficiencies could be further improved to 93.0-95.9% with the novel strategy. Obviously, the alternating anoxic/oxic strategy combined with step-feeding is the optimal way for TIN removal by granular sludge, which is independent of granule size.

Effects of inorganic nitrogen form on growth, morphology, N uptake, and nutrient allocation in hybrid Napier grass (Pennisetum purpureum × Pennisetum americanum cv. Pakchong1)

DEFF Research Database (Denmark)

Jampeetong, Arunothai; Brix, Hans; Kantawanichkul, Suwasa

2014-01-01

in such systems. We studied the effects of inorganic nitrogen form (NH4 +, NH4NO3 or NO3 -) on growth, morphology, N uptake, water content and mineral allocation in this species under hydroponic conditions at equimolar concentrations (500μmolNL-1). Generally, the N-form significantly affected growth, biomass...

Rapid estimation of organic nitrogen in oil shale waste waters

Energy Technology Data Exchange (ETDEWEB)

Jones, B.M.; Daughton, C.G.; Harris, G.J.

1984-04-01

Many of the characteristics of oil shale process waste waters (e.g., malodors, color, and resistance to biotreatment) are imparted by numerous nitrogenous heterocycles and aromatic amines. For the frequent performance assessment of waste treatment processes designed to remove these nitrogenous organic compounds, a rapid and colligative measurement of organic nitrogen is essential. Quantification of organic nitrogen in biological and agricultural samples is usually accomplished using the time-consuming, wet-chemical Kjeldahl method. For oil shale waste waters, whose primary inorganic nitorgen constituent is amonia, organic Kjeldahl nitrogen (OKN) is determined by first eliminating the endogenous ammonia by distillation and then digesting the sample in boiling H/sub 2/SO/sub 4/. The organic material is oxidized, and most forms of organically bound nitrogen are released as ammonium ion. After the addition of base, the ammonia is separated from the digestate by distillation and quantified by acidimetric titrimetry or colorimetry. The major failings of this method are the loss of volatile species such as aliphatic amines (during predistillation) and the inability to completely recover nitrogen from many nitrogenous heterocycles (during digestion). Within the last decade, a new approach has been developed for the quantification of total nitrogen (TN). The sample is first combusted, a

Development and application of the diffusive gradients in thin films technique for the measurement of total dissolved inorganic arsenic in waters

Energy Technology Data Exchange (ETDEWEB)

Panther, Jared G.; Stillwell, Kathryn P.; Powell, Kipton J. [Chemistry Department, University of Canterbury, Private Bag 4800, Christchurch (New Zealand); Downard, Alison J. [Chemistry Department, University of Canterbury, Private Bag 4800, Christchurch (New Zealand)], E-mail: alison.downard@canterbury.ac.nz

2008-08-01

The diffusive gradients in thin films (DGT) technique, utilizing an iron-hydroxide adsorbent, has been investigated for the in situ accumulation of total dissolved inorganic As in natural waters. Diffusion coefficients of the inorganic As{sup V} and As{sup III} species in the polyacrylamide gel were measured using a diffusion cell and DGT devices and a variety of factors that may affect the adsorption of the As species to the iron-hydroxide adsorbent, or the diffusion of the individual As species, were investigated. Under conditions commonly encountered in environmental samples, solution pH and the presence of anions, cations, fulvic acid, Fe{sup III}-fulvic acid complexes and colloidal iron-hydroxide were demonstrated not to affect uptake of dissolved As. To evaluate DGT as a method for accumulation and pre-concentration of total dissolved inorganic As in natural waters, DGT was applied to two well waters and a river water that was spiked with As. For each sample, the concentration obtained with use of DGT followed by measurement by hydride generation atomic absorption spectrometry with a Pd modifier (HG-AAS) was compared with the concentration of As measured directly by HG-AAS. The results confirmed that DGT is a reliable method for pre-concentration of total dissolved As.

Development and application of the diffusive gradients in thin films technique for the measurement of total dissolved inorganic arsenic in waters

International Nuclear Information System (INIS)

Panther, Jared G.; Stillwell, Kathryn P.; Powell, Kipton J.; Downard, Alison J.

2008-01-01

The diffusive gradients in thin films (DGT) technique, utilizing an iron-hydroxide adsorbent, has been investigated for the in situ accumulation of total dissolved inorganic As in natural waters. Diffusion coefficients of the inorganic As V and As III species in the polyacrylamide gel were measured using a diffusion cell and DGT devices and a variety of factors that may affect the adsorption of the As species to the iron-hydroxide adsorbent, or the diffusion of the individual As species, were investigated. Under conditions commonly encountered in environmental samples, solution pH and the presence of anions, cations, fulvic acid, Fe III -fulvic acid complexes and colloidal iron-hydroxide were demonstrated not to affect uptake of dissolved As. To evaluate DGT as a method for accumulation and pre-concentration of total dissolved inorganic As in natural waters, DGT was applied to two well waters and a river water that was spiked with As. For each sample, the concentration obtained with use of DGT followed by measurement by hydride generation atomic absorption spectrometry with a Pd modifier (HG-AAS) was compared with the concentration of As measured directly by HG-AAS. The results confirmed that DGT is a reliable method for pre-concentration of total dissolved As

Salicylate-spectrophotometric determination of inorganic monochloramine

International Nuclear Information System (INIS)

Tao Hui; Chen Zhonglin; Li Xing; Yang Yanling; Li Guibai

2008-01-01

On the basis of classical Berthelot reaction, a simple salicylate-spectrophotometric method was developed for quantitative determination of inorganic monochloramine in water samples. With the catalysis of disodium pentacyanonitrosylferrate(III), inorganic monochloramine reacts with salicylate in equimolar to produce indophenol compound which has an intense absorption at 703 nm. Parameters that influence method performance, such as pH, dosage of salicylate and nitroprussiate and reaction time, were modified to enhance the method performance. By using this method, inorganic monochloramine can be distinguished from organic chloramines and other inorganic chlorine species, such as free chlorine, dichloramine, and trichloramine. The molar absorptivities of the final products formed by these compounds are below ±3% of inorganic monochloramine, because of the α-N in them have only one exchangeable hydrogen atom, and cannot react with salicylate to produce the indophenol compound. The upper concentrations of typical ions that do not interfere with the inorganic monochloramine determination are also tested to be much higher than that mostly encountered in actual water treatment. Case study demonstrates that the results obtained from this method are lower than DPD-titrimetric method because the organic chloramines formed by chlorination of organic nitrogenous compounds give no response in the newly established method. And the result measured by salicylate-spectrophotometric method is coincident with theoretical calculation

Total Nitrogen in Surface Water

Data.gov (United States)

U.S. Environmental Protection Agency — Excess nitrogen in surface water can result in eutrophication. TOTALN is reported in kilograms/hectare/year. More information about these resources, including the...

Nitrogen isotope tracing of dissolved inorganic nitrogen behaviour in tidal estuaries

NARCIS (Netherlands)

Middelburg, J.J.; Nieuwenhuize, J.

2001-01-01

Concentration versus salinity diagrams are the most widely used method to derive estuarine sources and sinks of nitrogen. This method can not distinguish conservative mixing due to a lack of activity, from that due to an approximate balance of sources and sinks. The combined study of concentration

RESPONSE OF CHILE PEPPER (Capsicum annuum L. TO SALT STRESS AND ORGANIC AND INORGANIC NITROGEN SOURCES: I.GROWTH AND YIELD

Directory of Open Access Journals (Sweden)

Marco Antonio Huez Lopez

2010-10-01

Full Text Available The effect of two sources of nitrogen on plant growth, and fruit yield of chile pepper (Capsicum annuum L. cv. Sandia grown in greenhouse to increased salinity   were evaluated. An organic source extracted from grass clippings in rates of 120 and 200 kg N ha-1, and another inorganic (ammonium nitrate in rate of 120 kg ha-1 were combined with low, moderate and high (1.5, 4.5, and 6.5 dS m-1 salinity levels arranged in a randomized complete block design replicated four times. Salinity treatments reduced dry matter production, leaf area, relative growth rate and net assimilation rate but increased leaf area ratio. Mean fresh fruit yields decreased for each N rate and source combinations as soil salinity increased. The organic fertilizer produced higher fruit yields tan the inorganic fertilizer. The highest fruit yield was obtained with the increased rate of organic N.    The fruit number was more affected by salinity than the individual fruit weight. This organic fertilizer may be an effective N source for chile pepper and other vegetable crops grown under non- and salt-stressed conditions.

Dynamics of soil inorganic nitrogen and their responses to nitrogen additions in three subtropical forests, south China

Institute of Scientific and Technical Information of China (English)

FANG Yun-ting; ZHU Wei-xing; MO Jiang-ming; ZHOU Guo-yi; GUNDERSEN Per

2006-01-01

Three forests with different historical land-use, forest age, and species assemblages in subtropical China were selected to evaluate current soil N status and investigate the responses of soil inorganic N dynamics to monthly ammonium nitrate additions.Results showed that the mature monsoon evergreen broadleaved forest that has been protected for more than 400 years exhibited an advanced soil N status than the pine (Pinus massoniana) and pine-broadleaf mixed forests, both originated from the 1930's clear-cut and pine plantation. Mature forests had greater extractable inorganic N pool, lower N retention capacity, higher inorganic N leaching,and higher soil C/N ratios. Mineral soil extractable NH4+-N and NO3--N concentrations were significantly increased by experimental N additions on several sampling dates, but repeated ANOVA showed that the effect was not significant over the whole year except NH4+-N in the mature forest. In contrast, inorganic N (both NH4+-N and NO3--N) in soil 20-cm below the surface was significantly elevated by the N additions. From 42% to 74% of N added was retained by the upper 20 cm soils in the pine and mixed forests, while 0%-70% was retained in the mature forest. Our results suggest that land-use history, forest age and species composition were likely to be some of the important factors that determine differing forest N retention responses to elevated N deposition in the study region.

Stable nitrogen isotopes in coastal macroalgae: Geographic and anthropogenic variability

International Nuclear Information System (INIS)

Viana, Inés G.; Bode, Antonio

2013-01-01

Growing human population adds to the natural nitrogen loads to coastal waters. Both anthropogenic and natural nitrogen is readily incorporated in new biomass, and these different nitrogen sources may be traced by the measurement of the ratio of stable nitrogen isotopes (δ 15 N). In this study δ 15 N was determined in two species of macroalgae (Ascophyllum nodosum and Fucus vesiculosus), and in nitrate and ammonium to determine the relative importance of anthropogenic versus natural sources of nitrogen along the coast of NW Spain. Both algal species and nitrogen sources showed similar isotopic enrichment for a given site, but algal δ 15 N was not related to either inorganic nitrogen concentrations or δ 15 N in the water samples. The latter suggests that inorganic nitrogen inputs are variable and do not always leave an isotopic trace in macroalgae. However, a significant linear decrease in macroalgal δ 15 N along the coast is consistent with the differential effect of upwelling. Besides this geographic variability, the influence of anthropogenic nitrogen sources is evidenced by higher δ 15 N in macroalgae from rias and estuaries compared to those from open coastal areas and in areas with more than 15 × 10 3 inhabitants in the watershed. These results indicate that, in contrast with other studies, macroalgal δ 15 N is not simply related to either inorganic nitrogen concentrations or human population size but depends on other factors as the upwelling or the efficiency of local waste treatment systems. - Highlights: ► Anthropogenic versus upwelling nitrogen effect on macroalgal δ 15 N was studied. ► The influence of populations and upwelling has not been made before on macroalgal δ 15 N. ► Natural variability has not been taken into account in most biomonitoring studies. ► Upwelling explains most of the variability in δ 15 N in macroalgae

Anaerobic ammonium oxidation and its contribution to nitrogen removal in China’s coastal wetlands

Science.gov (United States)

Hou, Lijun; Zheng, Yanling; Liu, Min; Li, Xiaofei; Lin, Xianbiao; Yin, Guoyu; Gao, Juan; Deng, Fengyu; Chen, Fei; Jiang, Xiaofen

2015-01-01

Over the past several decades, human activities have caused substantial enrichment of reactive nitrogen in China’s coastal wetlands. Although anaerobic ammonium oxidation (anammox), the process of oxidizing ammonium into dinitrogen gas through the reduction of nitrite, is identified as an important process for removing reactive nitrogen, little is known about the dynamics of anammox and its contribution to nitrogen removal in nitrogen-enriched environments. Here, we examine potential rates of anammox and associate them with bacterial diversity and abundance across the coastal wetlands of China using molecular and isotope tracing techniques. High anammox bacterial diversity was detected in China’s coastal wetlands and included Candidatus Scalindua, Kuenenia, Brocadia, and Jettenia. Potential anammox rates were more closely associated with the abundance of anammox bacteria than to their diversity. Among all measured environmental variables, temperature was a key environmental factor, causing a latitudinal distribution of the anammox bacterial community composition, biodiversity and activity along the coastal wetlands of China. Based on nitrogen isotope tracing experiments, anammox was estimated to account for approximately 3.8–10.7% of the total reactive nitrogen removal in the study area. Combined with denitrification, anammox can remove 20.7% of the total external terrigenous inorganic nitrogen annually transported into China’s coastal wetland ecosystems. PMID:26494435

Fourier transform infrared spectroscopy, a new method for rapid determination of total organic and inorganic carbon and biogenic silica concentration in lake sediments

DEFF Research Database (Denmark)

Rosén, Peter; Vogel, Hendrik; Cunningham, Laura

2010-01-01

We demonstrate the use of Fourier transform infrared spectroscopy (FTIRS) to make quantitative measures of total organic carbon (TOC), total inorganic carbon (TIC) and biogenic silica (BSi) concentrations in sediment. FTIRS is a fast and cost-effective technique and only small sediment samples...... varied between r = 0.84-0.99 for TOC, r = 0.85-0.99 for TIC, and r = 0.68-0.94 for BSi. Because FTIR spectra contain information on a large number of both inorganic and organic components, there is great potential for FTIRS to become an important tool in paleolimnology....

Nitrogen Fixation in the Intertidal Sediments of the Yangtze Estuary: Occurrence and Environmental Implications

Science.gov (United States)

Hou, Lijun; Wang, Rong; Yin, Guoyu; Liu, Min; Zheng, Yanling

2018-03-01

Nitrogen fixation is a microbial-mediated process converting atmospheric dinitrogen gas to biologically available ammonia or other molecules, and it plays an important role in regulating nitrogen budgets in coastal marine ecosystems. In this study, nitrogen fixation in the intertidal sediments of the Yangtze Estuary was investigated using nitrogen isotope tracing technique. The abundance of nitrogen fixation functional gene (nifH) was also quantified. The measured rates of sediment nitrogen fixation ranged from 0.37 to 7.91 nmol N g-1 hr-1, while the abundance of nifH gene varied from 2.28 × 106 to 1.28 × 108 copies g-1 in the study area. The benthic nitrogen fixation was correlated closely to the abundance of nifH gene and was affected significantly by salinity, pH, and availability of sediment organic carbon and ammonium. It is estimated that sediment nitrogen fixation contributed approximately 9.3% of the total terrigenous inorganic nitrogen transported annually into the Yangtze estuarine and coastal environment. This result implies that the occurrence of benthic nitrogen fixation acts as an important internal source of reactive nitrogen and to some extent exacerbates nitrogen pollution in this aquatic ecosystem.

Dose equivalent distributions in the AAEC total body nitrogen facility

International Nuclear Information System (INIS)

Allen, B.J.; Bailey, G.M.; McGregor, B.J.

1985-01-01

The incident neutron dose equivalent in the AAEC total body nitrogen facility is measured by a calibrated remmeter. Dose equivalent rates and distributions are calculated by Monte Carlo techniques which take account of the secondary neutron flux from the collimator. Experiment and calculation are found to be in satisfactory agreement. The effective dose equivalent per exposure is determined by weighting organ doses, and the potential detriment per exposure is calculated from ICRP risk factors

Determination of total inorganic arsenic in potable water through spectroscopy of atomic absorption with generation of hydride

International Nuclear Information System (INIS)

Rodriguez Roman, S.

1997-01-01

This study developed a method for the cuantitative analysis of arsenic in potable water , through the spectrophotometric technique of atomic absorption. It used an automatic system of injection of flux for the generation of hydrides. It studied the effect produced by reducer agents, in the prereduction of arsenic in water, obtaining the best result with the use of potasium iodide 1.5% and ascorbic acid 0.25% in hydrochloric acid 3.7%, for the direct determination of total inorganic arsenic. It observed the effect produced by cadmium and selenium to the half of the concentration of arsenic, chromium, lead and silver at the same concentration, and barium at a ten times higher concentration, in the recuperation of total inorganic arsenic. It also used sodium borohydride 0.3% in sodium hydroxide 0.05% (5mL/min), for the formation of the volatile hydrides. It used hydrochloric acid 3.7% (12 mL/min) as disolution of transport; argon as inert gas, and a flame air-acetylene, for the atomization of the hydrides. This method was applied to 19 samples of potable water, and the result was no detectable for all of them. (S. Grainger)

Nitrogen uptake and assimilation by corn roots

International Nuclear Information System (INIS)

Yoneyama, Tadakatsu; Akiyama, Yoko; Kumazawa, Kikuo

1977-01-01

The site of nitrogen uptake in the apical root zone of corn was experimentally investigated. Two experiments were performed. The one is to see the assimilation of nitrate and ammonium and the effects of low temperature on it. The 4-day-old roots were treated with 15 N-labelled inorganic nitrogen of 20 ppm N in 5 x 10 -4 M CaSO 4 solution at 30 deg. C and 0 deg. C. The other is to see the nitrogen uptake at apical root zone and the utilization of newly absorbed nitrogen at the root top. The 4-day-old roots were transferred into 5 x 10 -4 M CaSO 4 solution containing 15 N-labelled ammonium nitrate of 40 ppm N. As a result, the effect of low temperature on the nitrogen uptake appeared to be more drastic in the case of nitrate than ammonium. The 15 N content of amino acids indicates that ammonium is assimilated into amino acids even at 0 deg. C, but nitrate is not. The ammonium nitrogen seemed to be absorbed at both cell dividing and elongating zones. On the other hand, nitrate nitrogen seemed to be strongly absorbed at cell elongating zone. The nitrogen in the apical part may be supplied not only by direct absorption but also by translocation from the basal part. The clear difference was found in the utilization of nitrate and ammonium nitrogen at the root top when the root was elongating. This may be due to the difference of assimilation products of inorganic nitrogen. Newly absorbed ammonium nitrogen is more utilizable for the growth of root top than nitrate nitrogen. (Iwakiri, K.)

Exchange of reactive nitrogen compounds: concentrations and fluxes of total ammonium and total nitrate above a spruce canopy

Directory of Open Access Journals (Sweden)

V. Wolff

2010-05-01

Full Text Available Total ammonium (tot-NH₄⁺ and total nitrate (tot-NO₃⁻ provide chemically conservative quantities in the measurement of surface exchange of reactive nitrogen compounds ammonia (NH₃, particulate ammonium (NH₄⁺, nitric acid (HNO₃, and particulate nitrate (NO₃⁻, using the aerodynamic gradient method. Total fluxes were derived from concentration differences of total ammonium (NH₃ and NH₄⁺ and total nitrate (HNO₃ and NO₃⁻ measured at two levels. Gaseous species and related particulate compounds were measured selectively, simultaneously and continuously above a spruce forest canopy in south-eastern Germany in summer 2007. Measurements were performed using a wet-chemical two-point gradient instrument, the GRAEGOR. Median concentrations of NH₃, HNO₃, NH₄⁺, and NO₃⁻ were 0.57, 0.12, 0.76, and 0.48 μg m⁻³, respectively. Total ammonium and total nitrate fluxes showed large variations depending on meteorological conditions, with concentrations close to zero under humid and cool conditions and higher concentrations under dry conditions. Mean fluxes of total ammonium and total nitrate in September 2007 were directed towards the forest canopy and were −65.77 ng m⁻² s⁻¹ and −41.02 ng m⁻² s⁻¹ (in terms of nitrogen, respectively. Their deposition was controlled by aerodynamic resistances only, with very little influence of surface resistances. Including measurements of wet deposition and findings of former studies on occult deposition (fog water interception at the study site, the total N deposition in September 2007 was estimated to 5.86 kg ha⁻¹.

Water-bearing explosive containing nitrogen-base salt

Energy Technology Data Exchange (ETDEWEB)

Dunglinson, C.; Lyerly, W.M.

1968-10-21

A water-bearing explosive composition consists of an oxidizing salt component, a fuel component, and water. A sensitizer is included having an oxygen balance more positive than -150%, and consisting of a salt of an inorganic oxidizing acid and of an acyclic nitrogen base having no more than 2 hydrogen atoms bonded to the basic nitrogen and up to 3 carbons per basic nitrogen, and/or of a phenyl amine. 41 claims.

Zeolite Soil Application Method Affects Inorganic Nitrogen, Moisture, and Corn Growth

Science.gov (United States)

Adoption of new management techniques which improve soil water storage and soil nitrogen plant availability yet limit nitrogen leaching may help improve environmental quality. A benchtop study was conducted to determine the influence of a single urea fertilizer rate (224 kilograms of Nitrogen per ...

Different nitrogen sources change the transcriptome of welan gum-producing strain Sphingomonas sp. ATCC 31555.

Science.gov (United States)

Xu, Xiaopeng; Nie, Zuoming; Zheng, Zhiyong; Zhu, Li; Zhang, Hongtao; Zhan, Xiaobei

2017-09-01

To reveal effects of different nitrogen sources on the expressions and functions of genes in Sphingomonas sp. ATCC 31555, it was cultivated in medium containing inorganic nitrogen (IN), organic nitrogen (ON), or inorganic-organic combined nitrogen (CN). Welan gum production and bacterial biomass were determined, and RNA sequencing (RNA-seq) was performed. Differentially expressed genes (DEGs) between the different ATCC 31555 groups were identified, and their functions were analyzed. Welan gum production and bacterial biomass were significantly higher in the ON and CN groups compared with those in the IN group. RNA-seq produced 660 unigenes, among which 488, 731, and 844 DEGs were identified between the IN vs. ON, IN vs. CN, and ON vs. CN groups, respectively. All the DEGs were related significantly to metabolic process and signal transduction. DEGs between the IN vs. CN and ON vs. CN groups were potentially associated with bacterial chemotaxis. Real-time PCR confirmed the expressions of selected DEGs. Organic nitrogen led to higher bacterial biomass and welan gum production than inorganic nitrogen, which might reflect differences in gene expression associated with metabolic process, signal transduction, and bacterial chemotaxis induced by different nitrogen sources.

TRANC - a novel fast-response converter to measure total reactive atmospheric nitrogen

Science.gov (United States)

Marx, O.; Brümmer, C.; Ammann, C.; Wolff, V.; Freibauer, A.

2012-05-01

The input and loss of plant available nitrogen (reactive nitrogen: Nr) from/to the atmosphere can be an important factor for the productivity of ecosystems and thus for its carbon and greenhouse gas exchange. We present a novel converter for reactive nitrogen (TRANC: Total Reactive Atmospheric Nitrogen Converter), which offers the opportunity to quantify the sum of all airborne reactive nitrogen compounds (∑Nr) in high time resolution. The basic concept of the TRANC is the full conversion of all Nr to nitrogen monoxide (NO) within two reaction steps. Initially, reduced Nr compounds are being oxidised, and oxidised Nr compounds are thermally converted to lower oxidation states. Particulate Nr is being sublimated and oxidised or reduced afterwards. In a second step, remaining higher nitrogen oxides or those generated in the first step are catalytically converted to NO with carbon monoxide used as reduction gas. The converter is combined with a fast response chemiluminescence detector (CLD) for NO analysis and its performance was tested for the most relevant gaseous and particulate Nr species under both laboratory and field conditions. Recovery rates during laboratory tests for NH3 and NO2 were found to be 95 and 99%, respectively, and 97% when the two gases were combined. In-field longterm stability over an 11-month period was approved by a value of 91% for NO2. Effective conversion was also found for ammonium and nitrate containing particles. The recovery rate of total ambient Nr was tested against the sum of individual measurements of NH3, HNO3, HONO, NH4+, NO3-, and NOx using a combination of different well-established devices. The results show that the TRANC-CLD system precisely captures fluctuations in ∑Nr concentrations and also matches the sum of all individual Nr compounds measured by the different single techniques. The TRANC features a specific design with very short distance between the sample air inlet and the place where the thermal and catalytic

Total mixed ration in exercising horse: digestibility and nitrogen metabolism

Directory of Open Access Journals (Sweden)

L. Magni

2010-04-01

Full Text Available The aim of this study was to evaluate the apparent digestibility of a total mixed ration (TMR versus a traditional mixed hay/cereals diet. Four adult trained Standardbred geldings – BW = 478±37 kg - were used. The two diets consisted of 20 kg of a commercial TMR - corn silage, alfalfa hay, wet brewers’ grain, oat, apple pomace, molasses cane, soybean oil and mineral/vitamin supplement - (Diet 1 or 7 kg of meadow hay and 4.5 kg of cereal-mix - corn, oat, barley and protein/mineral/vitamin supplement - (Diet 2. The trial was conducted according to a Latin Square design (2x2. After an adaptation period of four weeks, total faeces and urine were collected for 6 days. Both feed and faeces samples were analysed for DM, OM, CP, EE, CF, NDF, ADF, cellulose, hemicellulose, ADL and GE. Data were analysed by ANOVA. The apparent digestibility and nitrogen balance of the two diets were compared. DM, OM, CP and GE apparent digestibility were significantly different between the diets, with higher values for unifeed diet than traditional diet. Energy requirement was satisfied by both diets (96.54 vs 95.55 MJ. Nitrogen balance showed negative values in both diets (- 61.67 vs - 9.05, but the hay/cereals supplemented diet showed the best protein utilisation.

Nitrogen removal in maturation waste stabilisation ponds via biological uptake and sedimentation of dead biomass.

Science.gov (United States)

Camargo Valero, M A; Mara, D D; Newton, R J

2010-01-01

In this work a set of experiments was undertaken in a pilot-scale WSP system to determine the importance of organic nitrogen sedimentation on ammonium and total nitrogen removals in maturation ponds and its seasonal variation under British weather conditions, from September 2004 to May 2007. The nitrogen content in collected sediment samples varied from 4.17% to 6.78% (dry weight) and calculated nitrogen sedimentation rates ranged from 273 to 2868 g N/ha d. High ammonium removals were observed together with high concentrations of chlorophyll-a in the pond effluent. Moreover, chlorophyll-a had a very good correlation with the corresponding increment of VSS (algal biomass) and suspended organic nitrogen (biological nitrogen uptake) in the maturation pond effluents. Therefore, when ammonium removal reached its maximum, total nitrogen removal was very poor as most of the ammonia taken up by algae was washed out in the pond effluent in the form of suspended solids. After sedimentation of the dead algal biomass, it was clear that algal-cell nitrogen was recycled from the sludge layer into the pond water column. Recycled nitrogen can either be taken up by algae or washed out in the pond effluent. Biological (mainly algal) uptake of inorganic nitrogen species and further sedimentation of dead biomass (together with its subsequent mineralization) is one of the major mechanisms controlling in-pond nitrogen recycling in maturation WSP, particularly when environmental and operational conditions are favourable for algal growth.

Organic Nitrogen in Atmospheric Drops and Particles: Concentrations, (Limited) Speciation, and Chemical Transformations

Science.gov (United States)

Anastasio, C.; Zhang, Q.

2003-12-01

While quite a bit is known of the concentrations, speciation, and chemistry of inorganic forms of nitrogen in the atmosphere, the same cannot be said for organic forms. Despite this, there is growing evidence that organic N (ON) is ubiquitous in the atmosphere, especially in atmospheric condensed phases such as fog/cloud drops and aerosol particles. Although the major compounds that make up organic N are generally unknown, as are the sources of these compounds, it is clear that there are significant fluxes of ON between the atmosphere and ecosystems. It also appears that organic N can have significant effects in both spheres. The goal of our recent work in this area has been to better describe the atmospheric component of the biogeochemistry of organic nitrogen. Based on particle, gas, and fogwater samples from Northern California we have made three major findings: 1) Organic N represents a significant component, approximately 20%, of the total atmospheric N loading in these samples. This is broadly consistent with studies from other locations. 2) Amino compounds, primarily as combined amino acids, account for approximately 20% of the measured ON in our condensed phase samples. Given the properties of amino acids, these compounds could significantly affect the chemical and physical properties of atmospheric particles. 3) Organic nitrogen in atmospheric particles and drops is transformed to inorganic forms - primarily ammonium, nitrate, and nitrogen oxides (NOx) - during exposure to sunlight and/or ozone. These chemical reactions likely increase the bioavailability of the condensed phase nitrogen pool and enhance its biological effects after deposition to ecosystems.

Isotopic composition of dissolved inorganic nitrogen in high mountain lakes: variation with altitude in the Pyrenees

Science.gov (United States)

Bartrons, M.; Camarero, L.; Catalan, J.

2010-05-01

Nitrogen deposition in remote areas has increased, but the effect on ecosystems is still poorly understood. For aquatic systems, knowledge of the main processes driving the observed variation is limited, as is knowledge of how changes in nitrogen supply affect lake biogeochemical and food web processes. Differences in dissolved inorganic nitrogen (DIN) between lakes cannot be understood without considering catchment characteristics. In mountains, catchment features (e.g., thermal conditions, land cover) vary considerably with elevation. The isotopic composition of nitrogen (δ15N) is increasingly used to study aquatic ecosystem dynamics. Here we explore the variability of δ15N in DIN in high mountain lakes and show that environmental conditions that change with altitude can affect the isotopic ratio. We measured ammonium and nitrate δ15N values in atmospheric deposition, epilimnetic water, deep chlorophyll maximum water (DCMW) and sediment pore water (SPW) from eight mountain lakes in the Pyrenees, both above and below the treeline. Lakes showed relatively uniform δ15N-NH4+ values in SPW (2.2±1.6‰), with no variation corresponding to catchment or lake characteristics. We suggest that organic matter diagenesis under similar sediment conditions is responsible for the low variation between the lakes. In the water column, the range of δ15N values was larger for ammonium (-9.4‰ to 7.4‰) than for nitrate (-11.4‰ to -3.4‰), as a result of higher variation both between and within lakes (epilimnetic vs. DCM water). For both compounds part of the difference correlated with altitude or catchment features (e.g., scree proportion). Based on concentration, chemical and isotopic tendencies, we suggest that patterns arise from the distinct relative contributions of two types of water flow paths to the lakes: one from snowpack melting, with little soil interaction; and another highly influenced by soil conditions. The snow-type flow path contributes low DIN

A seasonal nitrogen deposition budget for Rocky Mountain National Park.

Science.gov (United States)

Benedict, K B; Carrico, C M; Kreidenweis, S M; Schichtel, B; Malm, W C; Collett, J L

2013-07-01

Nitrogen deposition is a concern in many protected ecosystems around the world, yet few studies have quantified a complete reactive nitrogen deposition budget including all dry and wet, inorganic and organic compounds. Critical loads that identify the level at which nitrogen deposition negatively affects an ecosystem are often defined using incomplete reactive nitrogen budgets. Frequently only wet deposition of ammonium and nitrate are considered, despite the importance of other nitrogen deposition pathways. Recently, dry deposition pathways including particulate ammonium and nitrate and gas phase nitric acid have been added to nitrogen deposition budgets. However, other nitrogen deposition pathways, including dry deposition of ammonia and wet deposition of organic nitrogen, still are rarely included. In this study, a more complete seasonal nitrogen deposition budget was constructed based on observations during a year-long study period from November 2008 to November 2009 at a location on the east side of Rocky Mountain National Park (RMNP), Colorado, USA. Measurements included wet deposition of ammonium, nitrate, and organic nitrogen, PM2.5 (particulate matter with an aerodynamic diameter less than 2.5 microm, nitrate, and ammonium) concentrations of ammonium, nitrate, and organic nitrogen, and atmospheric gas phase concentrations of ammonia, nitric acid, and NO2. Dry deposition fluxes were determined from measured ambient concentrations and modeled deposition velocities. Total reactive nitrogen deposition by all included pathways was found to be 3.65 kg N x ha(-1) yr(-1). Monthly deposition fluxes ranged from 0.06 to 0.54 kg N x ha(-1)yr(-1), with peak deposition in the month of July and the least deposition in December. Wet deposition of ammonium and nitrate were the two largest deposition pathways, together contributing 1.97 kg N x ha(-1)yr(-1) or 54% of the total nitrogen deposition budget for this region. The next two largest deposition pathways were wet

Effect of Nitrogen Form and pH of Nutrient Solution on the Shoot Concentration of Phosphorus, Nitrate, and Nitrogen of Spinach in Hydroponic Culture

OpenAIRE

N. Najafi; M. Parsazadeh

2010-01-01

In order to study the effect of nitrogen form and pH of nutrient solution on the shoot concentration of P, nitrate, organic N + inorganic ammonium, and total N of spinach, a factorial experiment was conducted with two factors including pH of nutrient solution in three levels (4.5, 6.5 and 8.0) and nitrate to ammonium ratio of nutrient solution in five levels (100:0, 75:25, 50:50, 25:75 and 0:100). This factorial experiment was carried out in a completely randomized design with four replicatio...

Organic, inorganic and total mercury determination in fish by chemical vapor generation with collection on a gold gauze and electrothermal atomic absorption spectrometry

International Nuclear Information System (INIS)

Duarte, Fabio Andrei; Bizzi, Cezar Augusto; Goldschmidt Antes, Fabiane; Dressler, Valderi Luiz; Flores, Erico Marlon de Moraes

2009-01-01

A method for organic, inorganic and total mercury determination in fish tissue has been developed using chemical vapor generation and collection of mercury vapor on a gold gauze inside a graphite tube and further atomization by electrothermal atomic absorption spectrometry. After drying and cryogenic grinding, potassium bromide and hydrochloric acid solution (1 mol L - 1 KBr in 6 mol L - 1 HCl) was added to the samples. After centrifugation, total mercury was determined in the supernatant. Organomercury compounds were selectively extracted from KBr solution using chloroform and the resultant solution was back extracted with 1% m/v L-cysteine. This solution was used for organic Hg determination. Inorganic Hg remaining in KBr solution was directly determined by chemical vapor generation electrothermal atomic absorption spectrometry. Mercury vapor generation from extracts was performed using 1 mol L - 1 HCl and 2.5% m/v NaBH 4 solutions and a batch chemical vapor generation system. Mercury vapor was collected on the gold gauze heated resistively at 80 deg. C and the atomization temperature was set at 650 deg. C. The selectivity of extraction was evaluated using liquid chromatography coupled to chemical vapor generation and determination by inductively coupled plasma mass spectrometry. The proposed method was applied for mercury analysis in shark, croaker and tuna fish tissues. Certified reference materials were used to check accuracy and the agreement was better than 95%. The characteristic mass was 60 pg and method limits of detection were 5, 1 and 1 ng g - 1 for organic, inorganic and total mercury, respectively. With the proposed method it was possible to analyze up to 2, 2 and 6 samples per hour for organic, inorganic and total Hg determination, respectively.

Inorganic arsenic levels in baby rice are of concern

International Nuclear Information System (INIS)

Meharg, Andrew A.; Sun, Guoxin; Williams, Paul N.; Adomako, Eureka; Deacon, Claire; Zhu, Yong-Guan; Feldmann, Joerg; Raab, Andrea

2008-01-01

Inorganic arsenic is a chronic exposure carcinogen. Analysis of UK baby rice revealed a median inorganic arsenic content (n = 17) of 0.11 mg/kg. By plotting inorganic arsenic against total arsenic, it was found that inorganic concentrations increased linearly up to 0.25 mg/kg total arsenic, then plateaued at 0.16 mg/kg at higher total arsenic concentrations. Inorganic arsenic intake by babies (4-12 months) was considered with respect to current dietary ingestion regulations. It was found that 35% of the baby rice samples analysed would be illegal for sale in China which has regulatory limit of 0.15 mg/kg inorganic arsenic. EU and US food regulations on arsenic are non-existent. When baby inorganic arsenic intake from rice was considered, median consumption (expressed as μg/kg/d) was higher than drinking water maximum exposures predicted for adults in these regions when water intake was expressed on a bodyweight basis. - Median consumption of organic arsenic levels for UK babies from baby rice is above threshold considered safe

Bioengineering Aspects of Inorganic Carbon Supply to Mass Algal Cultures: Final Report

Energy Technology Data Exchange (ETDEWEB)

Goldman, J. C.

1981-04-01

Regardless of the application, the basic biotechnology of large-scale outdoor cultures involves many common features, particularly in the requirement for adequate nutrients such as carbon, nitrogen, and phosphorus to ensure that light is the sole limiting yield determinant. Whereas the required quantities of nitrogen and phosphorus are fairly simple, to estimate, those for inorganic carbon are far more complex.

Efficient Total Nitrogen Removal in an Ammonia Gas Biofilter through High-Rate OLAND

DEFF Research Database (Denmark)

De Clippeleir, Haydée; Courtens, Emilie; Mosquera, Mariela

2012-01-01

Ammonia gas is conventionally treated in nitrifying biofilters; however, addition of organic carbon to perform post-denitrification is required to obtain total nitrogen removal. Oxygen-limited autotrophic nitrification/denitrification (OLAND), applied in full-scale for wastewater treatment, can...... offer a cost-effective alternative for gas treatment. In this study, the OLAND application thus was broadened toward ammonia loaded gaseous streams. A down flow, oxygen-saturated biofilter (height of 1.5 m; diameter of 0.11 m) was fed with an ammonia gas stream (248 ± 10 ppmv) at a loading rate of 0...... at water flow rates of 1.3 ± 0.4 m3 m–2 biofilter section d–1. Profile measurements revealed that 91% of the total nitrogen activity was taking place in the top 36% of the filter. This study demonstrated for the first time highly effective and sustainable autotrophic ammonia removal in a gas biofilter...

Stable nitrogen isotopes in coastal macroalgae: Geographic and anthropogenic variability

Energy Technology Data Exchange (ETDEWEB)

Viana, Inés G., E-mail: ines.gonzalez@co.ieo.es; Bode, Antonio

2013-01-15

Growing human population adds to the natural nitrogen loads to coastal waters. Both anthropogenic and natural nitrogen is readily incorporated in new biomass, and these different nitrogen sources may be traced by the measurement of the ratio of stable nitrogen isotopes (δ{sup 15}N). In this study δ{sup 15}N was determined in two species of macroalgae (Ascophyllum nodosum and Fucus vesiculosus), and in nitrate and ammonium to determine the relative importance of anthropogenic versus natural sources of nitrogen along the coast of NW Spain. Both algal species and nitrogen sources showed similar isotopic enrichment for a given site, but algal δ{sup 15}N was not related to either inorganic nitrogen concentrations or δ{sup 15}N in the water samples. The latter suggests that inorganic nitrogen inputs are variable and do not always leave an isotopic trace in macroalgae. However, a significant linear decrease in macroalgal δ{sup 15}N along the coast is consistent with the differential effect of upwelling. Besides this geographic variability, the influence of anthropogenic nitrogen sources is evidenced by higher δ{sup 15}N in macroalgae from rias and estuaries compared to those from open coastal areas and in areas with more than 15 × 10{sup 3} inhabitants in the watershed. These results indicate that, in contrast with other studies, macroalgal δ{sup 15}N is not simply related to either inorganic nitrogen concentrations or human population size but depends on other factors as the upwelling or the efficiency of local waste treatment systems. - Highlights: ► Anthropogenic versus upwelling nitrogen effect on macroalgal δ{sup 15}N was studied. ► The influence of populations and upwelling has not been made before on macroalgal δ{sup 15}N. ► Natural variability has not been taken into account in most biomonitoring studies. ► Upwelling explains most of the variability in δ{sup 15}N in macroalgae.

Organic and Inorganic Nitrogen Impact Chlorella variabilis Productivity and Host Quality for Viral Production and Cell Lysis.

Science.gov (United States)

Cheng, Yu-Shen; Labavitch, John; VanderGheynst, Jean S

2015-05-01

Microalgae have been proposed as a potential feedstock for biofuel production; however, cell disruption is usually required for collection and utilization of cytoplasmic polysaccharides and lipids. Virus infection might be one approach to disrupt the cell wall. The concentration of yeast extract and presence of KNO3 in algae cultivation media were investigated to observe their effects on Chlorella variabilis NC64A physiology and composition and the subsequent effect on production of Chlorella virus and disruption of infected cells. Cytoplasmic starch accumulation increased from 5% to approximately 35% of the total dry weight when yeast extract decreased from 1 to 0.25 g L(-1). When cells were cultured with the lowest nitrogen levels, the total polysaccharide accounted for more than 50% of the cell wall, which was 1.7 times higher than the content in cells cultured with the highest nitrogen levels. The C/N ratio of the algal biomass decreased by a factor of approximately 2 when yeast extract increased from 0.25 to 1 g L(-1). After virus infection, cells with a low C/N ratio produced a 7.6 times higher burst size than cells with a high C/N ratio, suggesting that the nitrogen content in C. variabilis has a large influence on viral production and cell lysis. The results have implications on management of nitrogen for both the synthesis of products from algae and product recovery via viral lysis.

Nitrogenous nutrients and primary production in a tropical oceanic environment

Digital Repository Service at National Institute of Oceanography (India)

Wafar, M.V.M.; Wafar, S.; Devassy, V.P.

Measurements of the concentrations of nitrogenous nutrients and primary production were made at 10 stations along 8 degrees N and 10 degrees N in the tropical oceanic Lakshadweep waters Inorganic nitrogen (NO3, NO2 and NH4) accounted for less than...

Potential for chlorate interference in ion chromatographic determination of total nitrogen in natural waters following alkaline persulfate digestion.

Science.gov (United States)

Halstead, J A; Edwards, J; Soracco, R J; Armstrong, R W

1999-10-01

Determination of total nitrogen in aqueous samples after thermal potassium peroxydisulfate (persulfate) digestion is a commonly used alternative to the tedious Kjeldahl procedure. When ion chromatography is used to quantify the nitrate formed during digestion, there is a potential for interference from a chlorate peak if the digested sample initially contained chloride in concentrations close to or greater than the concentration of nitrogen. It was determined that this interference can be avoided either by using chromatographic conditions which cleanly resolve the nitrate and chlorate peaks (e.g., the Dionex AG9-HG column) or by using digestion reagent concentrations chosen to maintain a high pH throughout the digestion. The second alternative is not a viable option for investigators using a single digestion for both total nitrogen (TN) and total phosphorus (TP) analysis.

Effect of organic and inorganic fertilizers on nutrient concentrations ...

African Journals Online (AJOL)

Effect of organic and inorganic fertilizers on nutrient concentrations in plantain ( Musa spp.) ... Fruit parameters measured were fruit weight, edible proportion and pulp dry matter content; also, the concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), iron (Fe) and zinc (Zn) in fruits were determined.

The Role of Water Movement and Spatial Scaling for Measurement of Dissolved Inorganic Nitrogen Fluxes in Intertidal Sediments

Science.gov (United States)

Asmus, R. M.; Jensen, M. H.; Jensen, K. M.; Kristensen, E.; Asmus, H.; Wille, A.

1998-02-01

Fluxes of dissolved inorganic nitrogen (ammonium and nitrate) across the sediment-water interface were determined at intertidal locations in Königshafen, northern Wadden Sea, North Sea. Three different incubation techniques were compared: closed sediment cores (small scale), closed bell jars (medium scale) and an open flow system (Sylt flume, large scale). Water movement in the two closed systems was maintained below the resuspension limit by spinning magnets (cores, incubated in the laboratory) or by transfer of wave action through flexible plastic foil (bell jars,in situ), whereas in the flume system (in situ) water movement was unidirectional, driven by currents and waves. Data sets from several years of core measurements (1992-94), bell jar measurements (1980) and flume campaigns (1990-93) served as the basis for a comparison of dissolved inorganic nitrogen fluxes. Fluxes of ammonium and nitrate were within the same order of magnitude in closed cores and bell jars, while flume rates of ammonium were considerably higher. The high flume rates were caused by advective flushing due to tidal water movement and wave action. The release of ammonium increased significantly with current velocity between 1 and 13 cm s-1. Fluxes of ammonium were higher in sediments withArenicola marinacompared to those without this bioturbating species. The influence of benthic microalgae was evident only in the small and medium scale core and bell jar systems as reduced ammonium release during light exposure. Nitrate was consumed by sediments in both closed systems at a rate proportional to the nitrate concentration in the overlying water. Nitrate fluxes in the large scale Sylt flume were low with an average of only 7% of the ammonium fluxes, probably due to low concentrations in tidal waters during measurements (summer). Both closed, small scale or open, large scale techniques can be applied successfully for benthic flux studies, but the actual choice depends on the purpose of the

The value of symbiotic nitrogen fixation by grain legumes in comparison to the cost of nitrogen fertilizer used in developing countries

International Nuclear Information System (INIS)

Hardarson, G.; Bunning, S.; Montanez, A.; Roy, R.; MacMillan, A.

2001-01-01

A great challenge lies in devising more sustainable farming systems without compromising food production levels and food security. Obviously, increasing productivity is necessary to accommodate growth in the global population. World wide, the environmental factors that most severely restrict plant growth are the availability of water and nitrogen. The challenges in developing countries are to find ways of meeting this additional nitrogen demand without concomitant degrading natural productivity. Widespread adoption of biological nitrogen fixation (BNF) would contribute to this goal. BNF, together with adequate N management in the ecosystem, appears to be the most promising alternative to increasing the use of inorganic fertiliser nitrogen. BNF technologies represent economic, sustainable and environmentally friendly means of ensuring the nitrogen requirement of an agro-ecosystem. Here we investigate the value of BNF by grain legumes and compares it to the cost of nitrogen fertilizer used in developing countries. Our data show that major grain legumes fix approximately 11.1 million metric tons of nitrogen per annum in developing countries. If this N was supplied by inorganic fertiliser one would have to apply at least double that amount to achieve the same yields, and this would cost approximately 6.7 billion US dollars. As the eight major grain legumes grown in developing countries contribute 30 - 40% of the annual N requirement the contribution of BNF is of great economic and environmental importance. (author)

Influence of organic waste and inorganic nitrogen source on biomass productivity of Scenedesmus and Chlorococcum sp.

Energy Technology Data Exchange (ETDEWEB)

Arumugam, M.; Agarwal, A.; Arya, M.C. [Defence Institute of Bio-Energy Research, Defence R and D Organization, Ministry of Defence, Govt. of India, Field Station Pithoragarh - 262501, Uttarakhand (India); Ahmed, Z. [Defence Institute of Bio-Energy Research, Defence R and D Organization, Ministry of Defence, Govt. of India Haldwani- 263 139, Uttarakhand (India)

2011-07-01

Algae gaining the more attention in the recent years in order to supplement the futuristic demand of fuel requirement because of its unique feature like high productivity, short duration and higher fatty acids content. However algal culturing for large-scale production is limited due to many technical and engineering challenges. One of the main constraints for large-scale biomass production is the non-availability of cost effective and affordable growth medium for open pond condition. In order to overcome this lacuna, the present study was carried out to find out the suitable cost effective growth medium using locally available resources. Farm Yard Manure an easily available organic waste yet, rich in nutrients and used for agriculture over the generations. FYM coupled with inorganic nitrogen source like urea was found to be better alternative to the synthetic growth medium, which may make wider acceptability at farmers' field for large-scale algal mass production. The present study reveals that FYM extract of 50% supplemented with 0.1% Urea was performing better for algal biomass growth in outdoor open pond condition.

Vertical nitrogen flux from the oceanic photic zone by diel migrant zooplankton and nekton

Science.gov (United States)

Longhurst, Alan R.; Glen Harrison, W.

1988-06-01

Where the photic zone is a biological steady-state, the downward flux of organic material across the pycnocline to the interior of the ocean is thought to be balanced by upward turbulent flux of inorganic nitrogen across the nutricline. This model ignores a significant downward dissolved nitrogen flux caused by the diel vertical migration of interzonal zooplankton and nekton that feed in the photic zone at night and excrete nitrogenous compounds at depth by day. In the oligotrophic ocean this flux can be equivalent to the flux of particulate organic nitrogen from the photic zone in the form of faecal pellets and organic flocculates. Where nitrogen is the limiting plant nutrient, and the flux by diel migration of interzonal plankton is significant compared to other nitrogen exports from the photic zone, there must be an upward revision of previous estimates for the ratio of new to total primary production in the photic zone if a nutrient balance is to be maintained. This upward revision is of the order 5-100% depending on the oceanographic regime.

Clinoptilolite zeolite influence on nitrogen in a manure-amended sandy agricultural soil

Science.gov (United States)

Development of best management practices can help improve inorganic nitrogen (N) availability to plants and reduce nitrate-nitrogen (NO3-N) leaching in soils. This study was conducted to determine the influence of the zeolite mineral clinoptilolite (CL) additions on NO3-N and ammonium-nitrogen (NH4-...

Effects of Nitrogen Supplementation on Yeast (Candida utilis Biomass Production by Using Pineapple (Ananas comosus Waste Extracted Medium

Directory of Open Access Journals (Sweden)

Rosma, A.

2007-01-01

Full Text Available Pineapple waste medium was used to cultivate yeast, Candida utilis. It served as the sole carbon and energy source for the yeast growth. However, pineapple waste media contain very little nitrogen (0.003-0.015% w/v. Various nitrogen sources were incorporate and their effects on biomass, yield and productivity were studied. Significant (p<0.05 increment on biomass production was observed when nitrogen supplement (commercial yeast extract, peptone, ammonium dihydrogen phosphate, ammonium sulphate and potassium nitrate was added into fermentation medium. Commercial yeast extract, Maxarome® which increased 55.2% of biomass production at 0.09% (w/v nitrogen content, is the most suitable among the selected organic source. On the other hand, ammonium dihydrogen phosphate at 0.09% (w/v nitrogen content is comparable inorganic source which enhanced 53.7% of production. Total nitrogen content of each treatment at 0.05% (w/v showed that nitrogen supplied was not fully utilized as substrate limitation in the fermentation medium.

On the water-soluble organic nitrogen concentration and mass size distribution during the fog season in the Po Valley, Italy.

Science.gov (United States)

Montero-Martínez, Guillermo; Rinaldi, Matteo; Gilardoni, Stefania; Giulianelli, Lara; Paglione, Marco; Decesari, Stefano; Fuzzi, Sandro; Facchini, Maria Cristina

2014-07-01

The study of organic nitrogen gained importance in recent decades due to its links with acid rain, pollution, and eutrophication. In this study, aerosol and fog water samples collected from two sites in Italy during November 2011 were analyzed to characterize their organic nitrogen content. Organic nitrogen contributed 19-25% of the total soluble nitrogen in the aerosol and around 13% in fog water. The largest water soluble organic nitrogen concentrations in the PM1.2 fraction occurred during the diurnal period with mean values of 2.03 and 2.16 μg-N m(-3) (154 and 145 nmol-N m(-3)) at Bologna and San Pietro Capofiume (SPC), respectively. The mean PM10 WSON concentration during diurnal periods at SPC was 2.30 μg-N m(-3) (164 nmol-N m(-3)) while it was 1.34 and 0.82 μg-N m(-3) (95.7 and 58.5 nmol-N m(-3)) in the night and fog water samples, respectively. Aerosol mass distribution profiles obtained during fog changed significantly with respect to those estimated in periods without fog periods due to fog scavenging, which proved to be over 80% efficient. Linear correlations suggested secondary processes related to combustion and, to a lesser extent, biomass burning, as plausible sources of WSON. Regarding the inorganic nitrogen fraction, the results showed that ammonium was the largest soluble inorganic nitrogen component in the samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Evaluation of nitrogen status and total chlorophyll in longkong (Aglaia dookkoo Griff. leaves under water stress using a chlorophyll meter

Directory of Open Access Journals (Sweden)

Sdoodee, S.

2005-07-01

Full Text Available A chlorophyll meter (SPAD-502 was used to assess nitrogen status and total chlorophyll in longkong leaves, leaves from twelve of 10-year-old trees grown in the experimental plot at Prince of Songkla University, Songkhla province. The relationship between SPAD-502 meter reading and nitrogen status and total chlorophyll content analyzed in the laboratory was evaluated during 8 months (May-December 2003. It was found that the trend of the relationships in each month was similar. There was no significant differenceamong regression linears of all months. The data of 8 months showed that SPAD-reading and nitrogen content, and SPAD-reading and total chlorophyll content were related in a positive manner. They were Y = 0.19X+10.10, r = 0.76** (n = 240, and Y = 0.43X-7.89, r = 0.79** (n = 400, respectively. The SPAD-502 was then used to assess total nitrogen and total chlorophyll content during imposed water stress. Fifteen 4-yearold plants were grown in pots (each pot containing 50 kg soil volume. The experiment was arranged in acompletely randomized design with 3 treatments: (1 daily watering (2 once watering on day 7 (3 no watering with 5 replications during 14 days of the experimental period. Measurements showed a continuous decrease of SPAD-reading in the treatment of no watering. On day 14, a significant difference of SPAD- reading values between the treatment of daily watering and no watering was found. Then, the values of nitrogen content and total chlorophyll were assessed by using the linear regression equations. From the result, it is suggested that the measurement by chlorophyll meter is a rapid technique for the evaluation of total chlorophyll and nitrogen status in longkong leaves during water stress.

Nitrous oxide emissions and soil mineral nitrogen status following application of hog slurry and inorganic fertilisers to acidic soils under forage grass

International Nuclear Information System (INIS)

Mkhabela, M.S.; Gordon, R.; Madani, A.; Burton, D.; Hart, W.

2008-01-01

This paper examined the influence of hog slurry and inorganic fertilizers on nitrous oxide (N 2 O) emissions and soil inorganic nitrogen (N) composition. Factors controlling N 2 O production were also identified. The study was comprised of 3 field experiments conducted during the summer months of 2005 on 2 acidic soils seeded with forage grass at a site in Nova Scotia. Treatments included hog slurry; ammonium sulphate; potassium nitrate; and an unamended control site. Emissions were measured using vented polyvinyl chloride static chambers. Gas fluxes and NO 2 measurements were analyzed using gas chromatography. Data were then subjected to analysis of variance (ANOVA). N 2 O flux and soil mineral N data from each sampling day were analyzed separately. Cumulative N 2 O losses were also calculated. Results demonstrated that the addition of hog slurry resulted in lower N 2 O emissions than the samples containing potassium nitrate fertilizer. The study also demonstrated that nitrate (NO 3 ) production drives NO 2 production in acidic soils. It was concluded that further research is needed to verify results obtained during the study. 29 refs., 3 tabs., 3 figs

Bulk deposition of organic and inorganic nitrogen in southwest China from 2008 to 2013

International Nuclear Information System (INIS)

Song, Ling; Kuang, Fuhong; Skiba, Ute; Zhu, Bo; Liu, Xuejun; Levy, Peter; Dore, Anthony; Fowler, David

2017-01-01

China is regarded as one of the nitrogen deposition hotspots in the world. Measurements to-date have focused mainly on the North China Plain, ignoring the fact that atmospheric chemical and physical properties vary across the country and that there may be other hotspots regions that should be investigated. For this reason we have conducted a six year study, measuring the bulk deposition of reduced (NH 4 -N), oxidized (NO 3 -N), and dissolved organic nitrogen (DON) at three contrasting sites in the Sichuan province, southwest China. The study sites were a high altitude forest in the Gongga Mountains (GG), an agriculture dominated region in Yanting (YT) and an urban site in the mega city Chengdu (CD). The annual average bulk deposition fluxes of total dissolved nitrogen (TDN) were 7.4, 23.1 and 36.6 kg N ha −1 yr −1 at GG, YT and CD sites, respectively, during the study period 2008 to 2013. The contributions of NH 4 -N, NO 3 -N and DON to the TDN were in the range of 48.4–57.8%, 28.8–43.7%, and 8.0–15.6%, respectively. DON bulk deposition was mainly dominated by agricultural activities. TDN bulk deposition fluxes showed increasing trends at the agricultural and urban sites from 2008 to 2013, but there was little change at the remote forest (GG) site. While reduced N dominated bulk N deposition at all the three sites, its contribution showed a decreasing trend, suggesting a gradual increase in the importance of oxidized N. These results reveal the value of long term monitoring in detecting changes in the atmospheric chemical composition of this rapidly changing region, and their inclusion in the policy debate regarding which sources should be controlled in order to reduce the long term impacts of N deposition, especially for southwest China, where there are few measurements of N deposition. - Highlights: • A region in southwest China was identified as a nitrogen deposition hotspot. • Agriculture was identified as the main source of organic nitrogen

Watershed scale spatial variability in dissolved and total organic and inorganic carbon in contrasting UK catchments

Science.gov (United States)

Cumberland, S.; Baker, A.; Hudson, N. J.

2006-12-01

investigations into carbon fluxes in British rivers have focused on long term increases in DOC in rural and predominantly upland catchments. Our results suggest that research is needed into understanding long term variations in inorganic carbon concentration, as well as total (organic and inorganic) carbon fluxes from British rivers, to obtain total carbon loads. In particular, we provide evidence that DIC concentrations may be greater in urbanized catchments compared to equivalent non-urban catchments, with the implication that increasing urbanization in the future will see increases in riverine DIC and a decrease in the strength of any DOC DIC anti correlation. Further studies of urban catchment DIC sources, within stream processing, long term trends, and potential ecological impacts, are required.

Deposition of nitrogen into the North Sea

DEFF Research Database (Denmark)

Leeuw, G. de; Skjøth, C.A.; Hertel, O.

2003-01-01

The flux of nitrogen species from the atmosphere into the ocean, with emphasis on coastal waters, was addressed during the ANICE project (Atmospheric Nitrogen Inputs into the Coastal Ecosystem). ANICE focused on quantifying the deposition of atmospheric inputs of inorganic nitrogen compounds (HNO3...... and Harwich/Newcastle. These measurements provided data for sensitivity studies of a variety of problems associated with the coastal region that are not easily evaluated with larger scale models, to constrain models and to test model results. Concentrations of nitrogen compounds over the North Sea...... on experimental results and small-scale model studies. In particular, effects of the aerosol size distribution on the nitrogen deposition are discussed. (C) 2003 Elsevier Ltd. All rights reserved....

Isotopic composition of dissolved inorganic nitrogen in high mountain lakes: variation with altitude in the Pyrenees

Directory of Open Access Journals (Sweden)

M. Bartrons

2010-05-01

Full Text Available Nitrogen deposition in remote areas has increased, but the effect on ecosystems is still poorly understood. For aquatic systems, knowledge of the main processes driving the observed variation is limited, as is knowledge of how changes in nitrogen supply affect lake biogeochemical and food web processes. Differences in dissolved inorganic nitrogen (DIN between lakes cannot be understood without considering catchment characteristics. In mountains, catchment features (e.g., thermal conditions, land cover vary considerably with elevation. The isotopic composition of nitrogen (δ¹⁵N is increasingly used to study aquatic ecosystem dynamics. Here we explore the variability of δ¹⁵N in DIN in high mountain lakes and show that environmental conditions that change with altitude can affect the isotopic ratio.

We measured ammonium and nitrate δ¹⁵N values in atmospheric deposition, epilimnetic water, deep chlorophyll maximum water (DCMW and sediment pore water (SPW from eight mountain lakes in the Pyrenees, both above and below the treeline. Lakes showed relatively uniform δ¹⁵N-NH₄⁺ values in SPW (2.2±1.6‰, with no variation corresponding to catchment or lake characteristics. We suggest that organic matter diagenesis under similar sediment conditions is responsible for the low variation between the lakes.

In the water column, the range of δ¹⁵N values was larger for ammonium (−9.4‰ to 7.4‰ than for nitrate (−11.4‰ to −3.4‰, as a result of higher variation both between and within lakes (epilimnetic vs. DCM water. For both compounds part of the difference correlated with altitude or catchment features (e.g., scree proportion. Based on concentration, chemical and isotopic tendencies, we suggest that patterns arise from the distinct relative contributions of two types of water flow paths to the lakes: one from snowpack melting, with little soil

Assessing total nitrogen in surface-water samples--precision and bias of analytical and computational methods

Science.gov (United States)

Rus, David L.; Patton, Charles J.; Mueller, David K.; Crawford, Charles G.

2013-01-01

The characterization of total-nitrogen (TN) concentrations is an important component of many surface-water-quality programs. However, three widely used methods for the determination of total nitrogen—(1) derived from the alkaline-persulfate digestion of whole-water samples (TN-A); (2) calculated as the sum of total Kjeldahl nitrogen and dissolved nitrate plus nitrite (TN-K); and (3) calculated as the sum of dissolved nitrogen and particulate nitrogen (TN-C)—all include inherent limitations. A digestion process is intended to convert multiple species of nitrogen that are present in the sample into one measureable species, but this process may introduce bias. TN-A results can be negatively biased in the presence of suspended sediment, and TN-K data can be positively biased in the presence of elevated nitrate because some nitrate is reduced to ammonia and is therefore counted twice in the computation of total nitrogen. Furthermore, TN-C may not be subject to bias but is comparatively imprecise. In this study, the effects of suspended-sediment and nitrate concentrations on the performance of these TN methods were assessed using synthetic samples developed in a laboratory as well as a series of stream samples. A 2007 laboratory experiment measured TN-A and TN-K in nutrient-fortified solutions that had been mixed with varying amounts of sediment-reference materials. This experiment identified a connection between suspended sediment and negative bias in TN-A and detected positive bias in TN-K in the presence of elevated nitrate. A 2009–10 synoptic-field study used samples from 77 stream-sampling sites to confirm that these biases were present in the field samples and evaluated the precision and bias of TN methods. The precision of TN-C and TN-K depended on the precision and relative amounts of the TN-component species used in their respective TN computations. Particulate nitrogen had an average variability (as determined by the relative standard deviation) of 13

Assessment of the characteristic of nutrients, total metals, and fecal coliform in Sibu Laut River, Sarawak, Malaysia

Science.gov (United States)

Soo, Chen-Lin; Ling, Teck-Yee; Lee, Nyanti; Apun, Kasing

2016-03-01

The concentrations of nutrients (nitrogen and phosphorus), total metals, and fecal coliform (FC) coupling with chlorophyll- a (chl- a), 5-day biochemical oxygen demand (BOD5) and other general environmental parameters were evaluated at the sub-surface and near-bottom water columns of 13 stations in the Sibu Laut River during low and high slack waters. The results indicated that inorganic nitrogen (mainly nitrate) was the primary form of nitrogen whereas organic phosphorus was the major form of phosphorus. The abundance of total heavy metals in Sibu Laut River and its tributaries was in the order of Pb < Cu < Zn < Cd. Fecal coliform concentration was relatively low along Sibu Laut River. The shrimp farm effluents contributed a substantial amount of chl- a, BOD5, nutrients, and FC to the receiving creek except for total metals. Nevertheless, the influence was merely noticeable in the intake creek and amended rapidly along Selang Sibu River and brought minimal effects on the Sibu Laut River. Besides, the domestic sewage effluents from villages nearby also contributed a substantial amount of pollutants.

Soil microbial community and its interaction with soil carbon and nitrogen dynamics following afforestation in central China.

Science.gov (United States)

Deng, Qi; Cheng, Xiaoli; Hui, Dafeng; Zhang, Qian; Li, Ming; Zhang, Quanfa

2016-01-15

Afforestation may alter soil microbial community structure and function, and further affect soil carbon (C) and nitrogen (N) dynamics. Here we investigated soil microbial carbon and nitrogen (MBC and MBN) and microbial community [e.g. bacteria (B), fungi (F)] derived from phospholipid fatty acids (PLFAs) analysis in afforested (implementing woodland and shrubland plantations) and adjacent croplands in central China. Relationships of microbial properties with biotic factors [litter, fine root, soil organic carbon (SOC), total nitrogen (TN) and inorganic N], abiotic factors (soil temperature, moisture and pH), and major biological processes [basal microbial respiration, microbial metabolic quotient (qCO2), net N mineralization and nitrification] were developed. Afforested soils had higher mean MBC, MBN and MBN:TN ratios than the croplands due to an increase in litter input, but had lower MBC:SOC ratio resulting from low-quality (higher C:N ratio) litter. Afforested soils also had higher F:B ratio, which was probably attributed to higher C:N ratios in litter and soil, and shifts of soil inorganic N forms, water, pH and disturbance. Alterations in soil microbial biomass and community structure following afforestation were associated with declines in basal microbial respiration, qCO2, net N mineralization and nitrification, which likely maintained higher soil carbon and nitrogen storage and stability. Copyright © 2015 Elsevier B.V. All rights reserved.

Export and retention of dissolved inorganic nutrients in the Cachoeira River, Ilhéus, Bahia, Brazil

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Maria A.M. SILVA

2010-02-01

Full Text Available Dissolved inorganic nutrient concentrations and physical-chemical variables were determined in the lower reaches of the Cachoeira River watershed, from November 2003 to October 2004. Concentration of nutrients were high and highly variable. Mean concentrations and standard deviation of ammonium, nitrite, nitrate, phosphate and silicate were 25.4 ± 25.1; 3.9 ± 3.9; 62.2 ± 54.9; 15.8 ± 9.0 and 129.0 ± 5.6 (μmol L-1, respectively. Nutrient retention was observed mainly during the dry season. Chlorophyll-a concentrations were especially high in those periods. The Cachoeira River can be considered eutrophicated, and such condition becomes more intense with low fluvial flow during the dry months. Despite the spatial/temporal changes of the species of inorganic nitrogen, a removal of dissolved inorganic nitrogen was observed in relation to dissolved silicon and to phosphorus, with consequences for estuarine biogeochemistry. The basin exports annually about 3.5, 2.2 and 0.3 t y-1 of dissolved silicon, nitrogen, and phosphate to the estuary, respectively. The eutrophication and growth of macrophytes is responsible for most of these changes in nutrient fluxes to the estuary and coastal waters.

Does the determination of inorganic arsenic in rice depend on the method?

DEFF Research Database (Denmark)

de la Calle, Maria Beatriz; Emteborg, Håkan; Linsinger, Thomas P.J.

2011-01-01

, on the determination of total and inorganic arsenic (As) in rice. The main aim of this PT was to judge the state of the art of analytical capability for the determination of total and inorganic As in rice. For this reason, participation in this exercise was open to laboratories from all over the world. Some 98...... laboratories reported results for total As and 32 for inorganic As. The main conclusions of IMEP-107 were that the concentration of inorganic As determined in rice does not depend on the analytical method applied and that introduction of a maximum level for inorganic As in rice should not be postponed because...

Short-term effects of tidal flooding on soil nitrogen mineralization in a Chinese tidal salt marsh

Science.gov (United States)

Gao, Haifeng; Bai, Junhong; Deng, Xiaoya; Lu, Qiongqiong; Ye, Xiaofei

2018-02-01

Tidal flooding is an important control of nitrogen biogeochemistry in wetland ecosystems of Yellow River Delta, China. Variations in hydrology could change soil redox dynamics and conditions for microorganisms living. A tidal simulation experiment was designed to extract tidal flooding effect on nitrogen mineralization of salt marsh soil. Inorganic nitrogen and relevant enzyme were measured during the 20-day incubation period. Considering the variation of both inorganic N and enzymes, nitrogen mineralization process in tidal salt marsh could be divided into 2 phases of short term response and longtime adaption by around 12th incubation day as the inflection point. Soil ammonium nitrogen (NH4+-N) and volatilized ammonia (NH3) occupied the mineralization process since nitrate nitrogen (NO3--N) was not detected over whole incubation period. NH4+-N varied fluctuant and increased significantly after 12 day's incubation. Released NH3 reached to peak value of 14.24 mg m-2 d-1 at the inflection point and declined thereafter. Inorganic nitrogen released according to net nitrogen mineralization rate (RM) under the tidal flooding condition without plant uptake except first 2 days. However, during the transitional period of 6-12 days, RM decreased notably to almost 0 and increased again after inflection point with the value of 0.182 mg kg-1 d-1. It might be due to the change of microbial composition and function when soil shifted from oxic to anoxic, which were reflected by arylamidase, urease and fluorescein diacetate. Fluorescein diacetate hydrolysis and arylamidase had the similar variation of U style with decreasing activities before 12 days' incubation. All the enzymes measured in this experiment increased after inflection point. Whereas, urease activity kept constant from 2 to 12 days. Alternant oxidation reduction condition would increase N loss through denitrification and ammonia volatilization during the transitional period, while more inorganic nitrogen would be

Evaluation of body composition and nitrogen content of renal patients on chronic dialysis as determined by total body neutron activation

International Nuclear Information System (INIS)

Cohn, S.H.; Brennan, B.L.; Yasumura, S.; Vartsky, D.; Vaswani, A.N.; Ellis, K.J.

1983-01-01

Total body protein (nitrogen), body cell mass (potassium), fat, and water were measured in 15 renal patients on maintenance hemodialysis (MHD). Total body nitrogen was measured by means of prompt γ neutron activation analysis; total body water was determined with tritium labeled water; total body potassium was measured by whole body counting. The extracellular water was determined by a technique utilizing the measurement of total body chloride and plasma chloride. When compared with corresponding values of a control group of the same age, sex, and height, the protein content, body cell mass, and total body fat of the MHD patients were within the normal range. The only significant change was an increase in the extracellular water/body cell mass ratio in the male MHD patients compared to the control. The lack of significant difference of the nitrogen values of the MHD patients compared to matched controls suggests that dialysis minimizes any residual effects of uremic toxicity or protein-calorie malnutrition. These findings further suggest that there is a need to reevaluate the traditional anthropometric and biochemical standards of nutritional status for MHD patients. It was concluded that it is particularly important to measure protein stores of MHD patients with low protein intake to ascertain nutritional status. Finally, in vivo measurement of total body nitrogen and potassium for determination of body composition provides a simple, direct, and accurate assessment of the nutritional status of MHD patients

TRANC – a novel fast-response converter to measure total reactive atmospheric nitrogen

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V. Wolff

2012-05-01

Full Text Available The input and loss of plant available nitrogen (reactive nitrogen: Nr from/to the atmosphere can be an important factor for the productivity of ecosystems and thus for its carbon and greenhouse gas exchange. We present a novel converter for reactive nitrogen (TRANC: Total Reactive Atmospheric Nitrogen Converter, which offers the opportunity to quantify the sum of all airborne reactive nitrogen compounds (∑Nr in high time resolution. The basic concept of the TRANC is the full conversion of all Nr to nitrogen monoxide (NO within two reaction steps. Initially, reduced Nr compounds are being oxidised, and oxidised Nr compounds are thermally converted to lower oxidation states. Particulate Nr is being sublimated and oxidised or reduced afterwards. In a second step, remaining higher nitrogen oxides or those generated in the first step are catalytically converted to NO with carbon monoxide used as reduction gas. The converter is combined with a fast response chemiluminescence detector (CLD for NO analysis and its performance was tested for the most relevant gaseous and particulate Nr species under both laboratory and field conditions. Recovery rates during laboratory tests for NH3 and NO2 were found to be 95 and 99%, respectively, and 97% when the two gases were combined. In-field longterm stability over an 11-month period was approved by a value of 91% for NO2. Effective conversion was also found for ammonium and nitrate containing particles. The recovery rate of total ambient Nr was tested against the sum of individual measurements of NH3, HNO3, HONO, NH4+, NO3−, and NOx using a combination of different well-established devices. The results show that the TRANC-CLD system precisely captures fluctuations in ∑Nr concentrations and also matches the sum of all individual Nr compounds measured by the different single techniques. The TRANC features a specific design with very short distance between the sample air inlet and the place where the thermal

Ralstonia solanacearum uses inorganic nitrogen metabolism for virulence, ATP production, and detoxification in the oxygen-limited host xylem environment.

Science.gov (United States)

Dalsing, Beth L; Truchon, Alicia N; Gonzalez-Orta, Enid T; Milling, Annett S; Allen, Caitilyn

2015-03-17

Genomic data predict that, in addition to oxygen, the bacterial plant pathogen Ralstonia solanacearum can use nitrate (NO3(-)), nitrite (NO2(-)), nitric oxide (NO), and nitrous oxide (N2O) as terminal electron acceptors (TEAs). Genes encoding inorganic nitrogen reduction were highly expressed during tomato bacterial wilt disease, when the pathogen grows in xylem vessels. Direct measurements found that tomato xylem fluid was low in oxygen, especially in plants infected by R. solanacearum. Xylem fluid contained ~25 mM NO3(-), corresponding to R. solanacearum's optimal NO3(-) concentration for anaerobic growth in vitro. We tested the hypothesis that R. solanacearum uses inorganic nitrogen species to respire and grow during pathogenesis by making deletion mutants that each lacked a step in nitrate respiration (ΔnarG), denitrification (ΔaniA, ΔnorB, and ΔnosZ), or NO detoxification (ΔhmpX). The ΔnarG, ΔaniA, and ΔnorB mutants grew poorly on NO3(-) compared to the wild type, and they had reduced adenylate energy charge levels under anaerobiosis. While NarG-dependent NO3(-) respiration directly enhanced growth, AniA-dependent NO2(-) reduction did not. NO2(-) and NO inhibited growth in culture, and their removal depended on denitrification and NO detoxification. Thus, NO3(-) acts as a TEA, but the resulting NO2(-) and NO likely do not. None of the mutants grew as well as the wild type in planta, and strains lacking AniA (NO2(-) reductase) or HmpX (NO detoxification) had reduced virulence on tomato. Thus, R. solanacearum exploits host NO3(-) to respire, grow, and cause disease. Degradation of NO2(-) and NO is also important for successful infection and depends on denitrification and NO detoxification systems. The plant-pathogenic bacterium Ralstonia solanacearum causes bacterial wilt, one of the world's most destructive crop diseases. This pathogen's explosive growth in plant vascular xylem is poorly understood. We used biochemical and genetic approaches to show

[Responses of rice-wheat rotation system in south Jiangsu to organic-inorganic compound fertilizers].

Science.gov (United States)

Tian, Heng-Da; Zhang, Li; Zhang, Jian-Chao; Wang, Qiu-Jun; Xu, Da-Bing; Yibati, Halihashi; Xu, Jia-Le; Huang, Qi-Wei

2011-11-01

In 2006-2007, a field trial was conducted to study the effects of applying three kinds of organic-inorganic compound fertilizers [rapeseed cake compost plus inorganic fertilizers (RCC), pig manure compost plus inorganic fertilizers (PMC), and Chinese medicine residues plus inorganic fertilizers (CMC)] on the crop growth and nitrogen (N) use efficiency of rice-wheat rotation system in South Jiangsu. Grain yield of wheat and rice in the different fertilization treatments was significantly higher than the control (no fertilization). In treatments RCC, PMC and CMC, the wheat yield was 13.1%, 32.2% and 39.3% lower than that of the NPK compound fertilizer (CF, 6760 kg x hm(-2)), respectively, but the rice yield (8504-9449 kg x hm(-2)) was significantly higher than that (7919 kg x hm(-2)) of CF, with an increment of 7.4%-19.3%. In wheat season, the aboveground dry mass, N accumulation, and N use efficiency in treatments RCC, PMC, and CMC were lower than those of CF, but in rice season, these parameters were significantly higher than or as the same as CF. In sum, all the test three compound fertilizers had positive effects on the rice yield and its nitrogen use efficiency in the rice-wheat rotation system, being most significant for RCC.

Effect of gamma irradiation on the total nitrogen and protein content in body during different stages of silkworm development

International Nuclear Information System (INIS)

Petkov, N.; Malinova, K.; Binkh, N.T.

1996-01-01

The aim was to determine the effect of gamma irradiation of eggs of silk moth in B 2 stage in doses of 1.00, 2.00 and 3.00 Gy on the changes of total nitrogen and protein content during different stages of Bombyx mori L. development. Highest levels of total nitrogen and protein were found in silk gland 14.032-14.355 mg%, followed by pupae - 7.448-8.092 and 46.550-48.906 mg%, moths after egg laying - 6.650-7.825 and 41.563-48.906 mg% and silkworm hemolymph - 6.920-6.980 and 43.250-43.625 mg%, respectively. The irradiation of eggs with 2.00 and 3,00 Gy gamma rays stimulated the increase of total nitrogen and protein content in silk gland by 6.66-7.3% compared to non-irradiated eggs of the same breed. 14 refs., 3 tabs. (author)

Nitrogen cycling in a turbid, tidal estuary

NARCIS (Netherlands)

Andersson, M.G.I.

2007-01-01

In this thesis I investigated nitrification, dissolved inorganic and organic nitrogen uptake, and the relative importance of nitrification and ammonium assimilation. I have also investigated exchange with marshes and sediments. Nitrification, oxidation of ammonium to nitrate is the first step for

Total water, phosphorus relaxation and inter-atomic organic to inorganic interface are new determinants of trabecular bone integrity.

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Ratan Kumar Rai

Full Text Available Bone is the living composite biomaterial having unique structural property. Presently, there is a considerable gap in our understanding of bone structure and composition in the native state, particularly with respect to the trabecular bone, which is metabolically more active than cortical bones, and is readily lost in post-menopausal osteoporosis. We used solid-state nuclear magnetic resonance (NMR to compare trabecular bone structure and composition in the native state between normal, bone loss and bone restoration conditions in rat. Trabecular osteopenia was induced by lactation as well as prolonged estrogen deficiency (bilateral ovariectomy, Ovx. Ovx rats with established osteopenia were administered with PTH (parathyroid hormone, trabecular restoration group, and restoration was allowed to become comparable to sham Ovx (control group using bone mineral density (BMD and µCT determinants. We used a technique combining (1H NMR spectroscopy with (31P and (13C to measure various NMR parameters described below. Our results revealed that trabecular bones had diminished total water content, inorganic phosphorus NMR relaxation time (T1 and space between the collagen and inorganic phosphorus in the osteopenic groups compared to control, and these changes were significantly reversed in the bone restoration group. Remarkably, bound water was decreased in both osteopenic and bone restoration groups compared to control. Total water and T1 correlated strongly with trabecular bone density, volume, thickness, connectivity, spacing and resistance to compression. Bound water did not correlate with any of the microarchitectural and compression parameters. We conclude that total water, T1 and atomic space between the crystal and organic surface are altered in the trabecular bones of osteopenic rats, and PTH reverses these parameters. Furthermore, from these data, it appears that total water and T1 could serve as trabecular surrogates of micro-architecture and

Competition for nitrogen sources between European beech (Fagus sylvatica) and sycamore maple (Acer pseudoplatanus) seedlings.

Science.gov (United States)

Simon, J; Waldhecker, P; Brüggemann, N; Rennenberg, H

2010-05-01

To investigate the short-term consequences of direct competition between beech and sycamore maple on root N uptake and N composition, mycorrhizal seedlings of both tree species were incubated for 4 days (i.e. beech only, sycamore maple only or both together) in an artificial nutrient solution with low N availability. On the fourth day, N uptake experiments were conducted to study the effects of competition on inorganic and organic N uptake. For this purpose, multiple N sources were applied with a single label. Furthermore, fine roots were sampled and analysed for total amino acids, soluble protein, total nitrogen, nitrate and ammonium content. Our results clearly show that both tree species were able to use inorganic and organic N sources. Uptake of inorganic and organic N by beech roots was negatively affected in the presence of the competing tree species. In contrast, the presence of beech stimulated inorganic N uptake by sycamore maple roots. Both the negative effect of sycamore maple on N uptake of beech and the positive effect of beech on N uptake of sycamore maple led to an increase in root soluble protein in beech, despite an overall decrease in total N concentration. Thus, beech compensated for the negative effects of the tree competitor on N uptake by incorporating less N into structural N components, but otherwise exhibited the same strategy as the competitor, namely, enhancing soluble protein levels in roots when grown under competition. It is speculated that enhanced enzyme activities of so far unknown nature are required in beech as a defence response to inter-specific competition.

Competition for inorganic and organic forms of nitrogen and phosphorous between phytoplankton and bacteria during an Emiliania huxleyi spring bloom

Directory of Open Access Journals (Sweden)

V. Martin-Jézéquel

2008-03-01

Full Text Available Using 15N and 33P, we measured the turnover of organic and inorganic nitrogen (N and phosphorus (P substrates, and the partitioning of N and P from these sources into two size fractions of marine osmotrophs during the course of a phytoplankton bloom in a nutrient manipulated mesocosm. The larger size fraction (>0.8 μm, mainly consisting of the coccolithophorid Emiliania huxleyi, but also including an increasing amount of large particle-associated bacteria as the bloom proceeded, dominated uptake of the inorganic forms NH4+, NO3−, and PO43−. The uptake of N from leucine, and P from ATP and dissolved DNA, was initially dominated by the 0.8–0.2 μm size fraction, but shifted towards dominance by the >0.8 μm size fraction as the system turned to an increasing degree of N-deficiency. Normalizing uptake to biomass of phytoplankton and heterotrophic bacteria revealed that organisms in the 0.8–0.2 μm size fraction had higher specific affinity for leucine-N than those in the >0.8 μm size fraction when N was deficient, whereas the opposite was the case for NH4+. There was no such difference regarding the specific affinity for P substrates. Since heterotrophic bacteria seem to acquire N from organic compounds like leucine more efficiently than phytoplankton, our results suggest different structuring of the microbial food chain in N-limited relative to P-limited environments.

Leaching of DOC, DN, and inorganic constituents from scrap tires.

Science.gov (United States)

Selbes, Meric; Yilmaz, Ozge; Khan, Abdul A; Karanfil, Tanju

2015-11-01

One concern for recycle and reuse of scrap tires is the leaching of tire constituents (organic and inorganic) with time, and their subsequent potential harmful impacts in environment. The main objective of this study was to examine the leaching of dissolved organic carbon (DOC), dissolved nitrogen (DN), and selected inorganic constituents from scrap tires. Different sizes of tire chips and crumb rubber were exposed to leaching solutions with pH's ranging from 3.0 to 10.0 for 28days. The leaching of DOC and DN were found to be higher for smaller size tire chips; however, the leaching of inorganic constituents was independent of the size. In general, basic pH conditions increased the leaching of DOC and DN, whereas acidic pH conditions led to elevated concentrations of metals. Leaching was minimal around the neutral pH values for all the monitored parameters. Analysis of the leaching rates showed that components associated with the rubbery portion of the tires (DOC, DN, zinc, calcium, magnesium, etc.) exhibited an initial rapid followed by a slow release. On the other hand, a constant rate of leaching was observed for iron and manganese, which are attributed to the metal wires present inside the tires. Although the total amounts that leached varied, the observed leaching rates were similar for all tire chip sizes and leaching solutions. Operation under neutral pH conditions, use of larger size tire chips, prewashing of tires, and removal of metal wires prior to application will reduce the impact of tire recycle and reuse. Copyright © 2015 Elsevier Ltd. All rights reserved.

Total inorganic arsenic detection in real water samples using anodic stripping voltammetry and a gold-coated diamond thin-film electrode.

Science.gov (United States)

Song, Yang; Swain, Greg M

2007-06-12

An accurate method for total inorganic arsenic determination in real water samples was developed using differential pulse anodic stripping voltammetry (DPASV) and a Au-coated boron-doped diamond thin-film electrode. Keys to the method are the use of a conducting diamond platform and solid phase extraction for sample preparation. In the method, the As(III) present in the sample is first detected by DPASV. The As(V) present is then reduced to As(III) by reaction with Na2SO3 and this is followed by a second detection of As(III) by DPASV. Interfering metal ions (e.g., Cu(II)) that cause decreased electrode response sensitivity for arsenic in real samples are removed by solid phase extraction as part of the sample preparation. For example, Cu(II) caused a 30% decrease in the As stripping peak current at a solution concentration ratio of 3:1 (Cu(II)/As(III)). This loss was mitigated by passage of the solution through a Chelex 100 cation exchange resin. After passage, only a 5% As stripping current response loss was seen. The effect of organic matter on the Au-coated diamond electrode response for As(III) was also evaluated. Humic acid at a 5 ppm concentration caused only a 9% decrease in the As stripping peak charge for Au-coated diamond. By comparison, a 50% response decrease was observed for Au foil. Clearly, the chemical properties of the diamond surface in the vicinity of the metal deposits inhibit molecular adsorption on at least some of the Au surface. The method provided reproducible and accurate results for total inorganic arsenic in two contaminated water samples provided by the U.S. Bureau of Reclamation. The total inorganic As concentration in the two samples, quantified by the standard addition method, was 23.2+/-2.9 ppb for UV plant influent water and 16.4+/-0.9 ppb for Well 119 water (n=4). These values differed from the specified concentrations by less than 4%.

Total inorganic arsenic detection in real water samples using anodic stripping voltammetry and a gold-coated diamond thin-film electrode

International Nuclear Information System (INIS)

Song Yang; Swain, Greg M.

2007-01-01

An accurate method for total inorganic arsenic determination in real water samples was developed using differential pulse anodic stripping voltammetry (DPASV) and a Au-coated boron-doped diamond thin-film electrode. Keys to the method are the use of a conducting diamond platform and solid phase extraction for sample preparation. In the method, the As(III) present in the sample is first detected by DPASV. The As(V) present is then reduced to As(III) by reaction with Na 2 SO 3 and this is followed by a second detection of As(III) by DPASV. Interfering metal ions (e.g., Cu(II)) that cause decreased electrode response sensitivity for arsenic in real samples are removed by solid phase extraction as part of the sample preparation. For example, Cu(II) caused a 30% decrease in the As stripping peak current at a solution concentration ratio of 3:1 (Cu(II)/As(III)). This loss was mitigated by passage of the solution through a Chelex 100 cation exchange resin. After passage, only a 5% As stripping current response loss was seen. The effect of organic matter on the Au-coated diamond electrode response for As(III) was also evaluated. Humic acid at a 5 ppm concentration caused only a 9% decrease in the As stripping peak charge for Au-coated diamond. By comparison, a 50% response decrease was observed for Au foil. Clearly, the chemical properties of the diamond surface in the vicinity of the metal deposits inhibit molecular adsorption on at least some of the Au surface. The method provided reproducible and accurate results for total inorganic arsenic in two contaminated water samples provided by the U.S. Bureau of Reclamation. The total inorganic As concentration in the two samples, quantified by the standard addition method, was 23.2 ± 2.9 ppb for UV plant influent water and 16.4 ± 0.9 ppb for Well 119 water (n = 4). These values differed from the specified concentrations by less than 4%

Biogeochemical spatio-temporal transformation of copper in Aspergillus niger colonies grown on malachite with different inorganic nitrogen sources.

Science.gov (United States)

Fomina, Marina; Bowen, Andrew D; Charnock, John M; Podgorsky, Valentin S; Gadd, Geoffrey M

2017-03-01

This work elucidates spatio-temporal aspects of the biogeochemical transformation of copper mobilized from malachite (Cu 2 (CO 3 )(OH) 2 ) and bioaccumulated within Aspergillus niger colonies when grown on different inorganic nitrogen sources. It was shown that the use of either ammonium or nitrate determined how copper was distributed within the colony and its microenvironment and the copper oxidation state and succession of copper coordinating ligands within the biomass. Nitrate-grown colonies yielded ∼1.7× more biomass, bioaccumulated ∼7× less copper, excreted ∼1.9× more oxalate and produced ∼1.75× less water-soluble copper in the medium in contrast to ammonium-grown colonies. Microfocus X-ray absorption spectroscopy revealed that as the mycelium matured, bioaccumulated copper was transformed from less stable and more toxic Cu(I) into less toxic Cu(II) which was coordinated predominantly by phosphate/malate ligands. With time, a shift to oxalate coordination of bioaccumulated copper occurred in the central older region of ammonium-grown colonies. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

The effect of Landscape on Riverine Dissolved Inorganic Nitrogen Yield in populous watershed in the Danshui River in Taiwan

Science.gov (United States)

Shih, Yu-Ting; Lee, Tsung-Yu; Huang, -Chuan, Jr.

2015-04-01

This study combines the observed riverine DIN (dissolved inorganic nitrogen) export and the controlling factors (land-use, population and discharge) to inversely estimate the effective DIN yield factors for individual land-use and DIN per capita loading. A total of 16 sub-catchments, with different land-use compositions on the Danshui River of Taiwan, were used in this study. Observed riverine DIN concentrations and yields varied from 20 - 450 μM and 400 - 10,000 kg-N km-2 yr-1 corresponding to the increase of urbanization gradient (e.g. building and population). Meanwhile, the transport behaviors changed from hydrological enhancement to dilution with increasing urbanization as well. Our method shows that the DIN yield factors, independent of discharge, are 12.7, 63.9, and 1381.0 μM, for forest, agriculture, and building, respectively, which equals to 444.5, 2236.5, 48,335 kg-N km-2 yr-1 at the given annual runoff of 2,500 mm. The agriculture DIN yield only accounts for 10% of fertilizer application indicating the complicated N cascade and possible over fertilization. The DIN per capita loading (~0.49 kg-N Capita-1 yr-1) which is lower than the documented human N emission (1.6 - 5.5 kg-N Capita-1 yr-1) can be regarded as an effective export coefficient after treatment or retention. A conducted scenario experiment supports the observations demonstrating the capability for assessment. We therefore, can extrapolate all possible combinations of land-use, discharge, and population density for evaluation. This can provide a strong basis for watershed management and supplementary estimation for regional to global study.

Inverse isolation of dissolved inorganic nitrogen yield for individual land-uses from mosaic land-use patterns within a watershed

Science.gov (United States)

Shih, Y.-T.; Lee, T.-Y.; Huang, J.-C.; Kao, S.-J.; Liu, K.-K.; Chang, F.-J.

2015-01-01

This study combines the observed riverine DIN (dissolved inorganic nitrogen) export and the controlling factors (land-use, population and discharge) to inversely estimate the effective DIN yield factors for individual land-use and DIN per capita loading. A total of 16 sub-catchments, with different land-use compositions on the Danshui River of Taiwan, were used in this study. Observed riverine DIN concentrations and yields varied from 20-450 μM and 400-10 000 kg N km-2 yr-1 corresponding to the increase of urbanization gradient (e.g. building and population). Meanwhile, the transport behaviors changed from hydrological enhancement to dilution with increasing urbanization as well. Our method shows that the DIN yield factors, independent of discharge, are 12.7, 63.9, and 1381.0 μM, for forest, agriculture, and building, respectively, which equals to 444.5, 2236.5, 48 335 kg N km-2 yr-1 at the given annual runoff of 2500 mm. The agriculture DIN yield only accounts for 10% of fertilizer application indicating the complicated N cascade and possible over fertilization. The DIN per capita loading (~0.49 kg N capita-1 yr-1) which is lower than the documented human N emission (1.6-5.5 kg N capita-1 yr-1) can be regarded as an effective export coefficient after treatment or retention. A conducted scenario experiment supports the observations demonstrating the capability for assessment. We therefore, can extrapolate all possible combinations of land-use, discharge, and population density for evaluation. This can provide a strong basis for watershed management and supplementary estimation for regional to global study.

Influence of total beam current on HRTEM image resolution in differentially pumped ETEM with nitrogen gas

International Nuclear Information System (INIS)

Bright, A.N.; Yoshida, K.; Tanaka, N.

2013-01-01

Environmental transmission electron microscopy (ETEM) enables the study of catalytic and other reaction processes as they occur with Angstrom-level resolution. The microscope used is a dedicated ETEM (Titan ETEM, FEI Company) with a differential pumping vacuum system and apertures, allowing aberration corrected high-resolution transmission electron microscopy (HRTEM) imaging to be performed with gas pressures up to 20 mbar in the sample area and with significant advantages over membrane-type E-cell holders. The effect on image resolution of varying the nitrogen gas pressure, electron beam current density and total beam current were measured using information limit (Young's fringes) on a standard cross grating sample and from silicon crystal lattice imaging. As expected, increasing gas pressure causes a decrease in HRTEM image resolution. However, the total electron beam current also causes big changes in the image resolution (lower beam current giving better resolution), whereas varying the beam current density has almost no effect on resolution, a result that has not been reported previously. This behavior is seen even with zero-loss filtered imaging, which we believe shows that the drop in resolution is caused by elastic scattering at gas ions created by the incident electron beam. Suitable conditions for acquiring high resolution images in a gas environment are discussed. Lattice images at nitrogen pressures up to 16 mbar are shown, with 0.12 nm information transfer at 4 mbar. -- Highlights: ► ETEM images with point resolution of 0.12 nm in 4 mbar of nitrogen gas. ► Clear Si lattice imaging with 16 mbar of nitrogen gas. ► ETEM image resolution in gas can be much improved by decreasing total beam current. ► Beam current density (beam convergence) has no effect on the image resolution.

Growth responses of Ulva prolifera to inorganic and organic nutrients: Implications for macroalgal blooms in the southern Yellow Sea, China

Science.gov (United States)

Li, Hongmei; Zhang, Yongyu; Han, Xiurong; Shi, Xiaoyong; Rivkin, Richard B.; Legendre, Louis

2016-05-01

The marine macrophyte Ulva prolifera is the dominant green-tide-forming seaweed in the southern Yellow Sea, China. Here we assessed, in the laboratory, the growth rate and nutrient uptake responses of U. prolifera to different nutrient treatments. The growth rates were enhanced in incubations with added organic and inorganic nitrogen [i.e. nitrate (NO3-), ammonium (NH4+), urea and glycine] and phosphorus [i.e. phosphate (PO43-), adenosine triphosphate (ATP) and glucose 6-phosphate (G-6-P)], relative to the control. The relative growth rates of U. prolifera were higher when enriched with dissolved organic nitrogen (urea and glycine) and phosphorus (ATP and G-6-P) than inorganic nitrogen (NO3- and NH4+) and phosphorus (PO43-). In contrast, the affinity was higher for inorganic than organic nutrients. Field data in the southern Yellow Sea showed significant inverse correlations between macroalgal biomass and dissolved organic nutrients. Our laboratory and field results indicated that organic nutrients such as urea, glycine and ATP, may contribute to the development of macroalgal blooms in the southern Yellow Sea.

Atmospheric ammonia measurements along the coastal lines of Southeastern China: Implications for inorganic nitrogen deposition to coastal waters

Science.gov (United States)

Wu, Shui-Ping; Dai, Lu-Hong; Wei, Ya; Zhu, Heng; Zhang, Yin-Ju; Schwab, James J.; Yuan, Chung-Shin

2018-03-01

Ambient NH3 concentrations were determined using Ogawa passive samplers along the coastal lines of southeast China from June 2015 to May 2017. Additional monitoring of PM2.5 and precipitation around Xiamen Bay during the period from November 2015 to May 2017 were carried out to estimate atmospheric inorganic nitrogen (IN) deposition to the bay. Distinct seasonal variations of ambient NH3 were observed with summer averages 1.41-5.56 times higher than winter, which agreed well with the seasonal trend of air temperature. Nitrate concentrations (pNO3-) in PM2.5 were significantly higher than ammonium concentrations (pNH4+), and both species showed higher concentrations in winter and spring and lower values in summer and fall which were influenced mainly by the monsoon cycle, gas-to-particle transformation process and rain washout. Paired t-testing revealed that no significant differences of pNO3- and pNH4+ between the urban and suburban sites around the Xiamen Bay. Unlike pNO3- and pNH4+, there were no clear seasonal trends for NH4+ and NO3- concentrations in precipitation samples (wNH4+ and wNO3-). On average, the deposition of IN consisted of NH3-N (27.4-28.2%) and pNO3--N (25.9-26.8%), followed by pNH4+-N (17.0-17.7%), wNH4+-N (14.5%), wNO3--N (13.3-13.8%) and NO2-N (0.35-0.46%); and showed distinct seasonal trends with higher values in winter/spring and lower values in summer/fall. In 2016, the total IN deposition was determined to be 36.45 and 35.92 kg N ha-1 at the urban and suburban sites around the Xiamen Bay, respectively. The proportion of IN deposition to total IN loads (terrestrial + atmospheric), varied over the range of 7.1-13.3% depending on the data source of riverine influx. Our observations revealed that the total IN deposition could account for 9.6-25.1% (based on primary productivity over Taiwan Strait) and 1.7-5.3% (based on primary productivity in Guangdong coastal region) of new productivity in Xiamen Bay, respectively. As an important nutrient

Data Analysis of Minima Total Cross-sections of Nitrogen-14 on JENDL-3.2Nuclear Data File

International Nuclear Information System (INIS)

Suwoto; Pandiangan, Tumpal; Ferhat-Aziz

2000-01-01

The integral tests of neutron cross-section for shielding material suchas nitrogen-14 contained in JENDL-3.2 file have been performed. Analysis ofthe calculation for nitrogen-14 was based on the MAEKER's ORNL-BroomstickExperiment at ORNL-USA. For the data comparison, the calculation analysiswith JENDL-3.1 file, ENDF/B-IV file, ENDF/B-VI file and JEF2.2 have also beencarried out. The overall calculation results by using JENDL-3.2 evaluationshowed good agreement with the experimental data, as well as those with theENDF/B-VI evaluation. In particular, the JENDL-3.2 evaluation gave betterresults than JENDL-3.1 evaluation and ENDF/B-IV. It was been concluded thatthe total cross-sections of Nitrogen-14 contained in JENDL-3.2 file is invery good agreement with the experimental results, although the totalcross-section in the energy range between 0.5 MeV and 0.9 MeV on fileJENDL-3.2 was small (about 4% lower), and minima of total cross-sections wasdeeper. (author)

[Effects of controlled release blend bulk urea on soil nitrogen and soil enzyme activity in wheat and rice fields].

Science.gov (United States)

Zhang, Jing Sheng; Wang, Chang Quan; Li, Bing; Liang, Jing Yue; He, Jie; Xiang, Hao; Yin, Bin; Luo, Jing

2017-06-18

A field experiment was conducted to investigate the effect of controlled-release fertilizer (CRF) combined with urea (UR) on the soil fertility and environment in wheat-rice rotation system. Changes in four forms of nitrogen (total nitrogen, ammonium nitrogen, nitrate nitrogen, and microbial biomass nitrogen) and in activities of three soil enzymes participating in nitrogen transformation (urease, protease, and nitrate reductase) were measured in seven fertilization treatments (no fertilization, routine fertilization, 10%CRF+90%UR, 20%CRF+80%UR, 40%CRF+60%UR, 80%CRF+20%UR, and 100%CRF). The results showed that soil total nitrogen was stable in the whole growth period of wheat and rice. There was no significant difference among the treatments of over 20% CRF in soil total nitrogen content of wheat and rice. The soil inorganic nitrogen content was increased dramatically in treatments of 40% or above CRF during the mid-late growing stages of wheat and rice. With the advance of the growth period, conventional fertilization significantly decreased soil microbial biomass nitrogen, but the treatments of 40% and above CRF increased the soil microbial biomass nitrogen significantly. The soil enzyme activities were increased with over 40% of CRF in the mid-late growing stage of wheat and rice. By increasing the CRF ratio, the soil protease activity and nitrate reductase activity were improved gradually, and peaked in 100% CRF. The treatments of above 20% CRF could decrease the urease activity in tillering stage of rice and delay the peak of ammonium nitrogen, which would benefit nitrogen loss reduction. The treatments of 40% and above CRF were beneficial to improving soil nitrogen supply and enhancing soil urease and protease activities, which could promote the effectiveness of nitrogen during the later growth stages of wheat and rice. The 100% CRF treatment improved the nitrate reductase activity significantly during the later stage of wheat and rice. Compared with the

Coral uptake of inorganic phosphorus and nitrogen negatively affected by simultaneous changes in temperature and pH.

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Claire Godinot

Full Text Available The effects of ocean acidification and elevated seawater temperature on coral calcification and photosynthesis have been extensively investigated over the last two decades, whereas they are still unknown on nutrient uptake, despite their importance for coral energetics. We therefore studied the separate and combined impacts of increases in temperature and pCO(2 on phosphate, ammonium, and nitrate uptake rates by the scleractinian coral S. pistillata. Three experiments were performed, during 10 days i at three pH(T conditions (8.1, 7.8, and 7.5 and normal temperature (26°C, ii at three temperature conditions (26°, 29°C, and 33°C and normal pH(T (8.1, and iii at three pH(T conditions (8.1, 7.8, and 7.5 and elevated temperature (33°C. After 10 days of incubation, corals had not bleached, as protein, chlorophyll, and zooxanthellae contents were the same in all treatments. However, photosynthetic rates significantly decreased at 33°C, and were further reduced for the pH(T 7.5. The photosynthetic efficiency of PSII was only decreased by elevated temperature. Nutrient uptake rates were not affected by a change in pH alone. Conversely, elevated temperature (33°C alone induced an increase in phosphate uptake but a severe decrease in nitrate and ammonium uptake rates, even leading to a release of nitrogen into seawater. Combination of high temperature (33°C and low pH(T (7.5 resulted in a significant decrease in phosphate and nitrate uptake rates compared to control corals (26°C, pH(T = 8.1. These results indicate that both inorganic nitrogen and phosphorus metabolism may be negatively affected by the cumulative effects of ocean warming and acidification.

Coral Uptake of Inorganic Phosphorus and Nitrogen Negatively Affected by Simultaneous Changes in Temperature and pH

Science.gov (United States)

Godinot, Claire; Houlbrèque, Fanny

2011-01-01

The effects of ocean acidification and elevated seawater temperature on coral calcification and photosynthesis have been extensively investigated over the last two decades, whereas they are still unknown on nutrient uptake, despite their importance for coral energetics. We therefore studied the separate and combined impacts of increases in temperature and pCO2 on phosphate, ammonium, and nitrate uptake rates by the scleractinian coral S. pistillata. Three experiments were performed, during 10 days i) at three pHT conditions (8.1, 7.8, and 7.5) and normal temperature (26°C), ii) at three temperature conditions (26°, 29°C, and 33°C) and normal pHT (8.1), and iii) at three pHT conditions (8.1, 7.8, and 7.5) and elevated temperature (33°C). After 10 days of incubation, corals had not bleached, as protein, chlorophyll, and zooxanthellae contents were the same in all treatments. However, photosynthetic rates significantly decreased at 33°C, and were further reduced for the pHT 7.5. The photosynthetic efficiency of PSII was only decreased by elevated temperature. Nutrient uptake rates were not affected by a change in pH alone. Conversely, elevated temperature (33°C) alone induced an increase in phosphate uptake but a severe decrease in nitrate and ammonium uptake rates, even leading to a release of nitrogen into seawater. Combination of high temperature (33°C) and low pHT (7.5) resulted in a significant decrease in phosphate and nitrate uptake rates compared to control corals (26°C, pHT = 8.1). These results indicate that both inorganic nitrogen and phosphorus metabolism may be negatively affected by the cumulative effects of ocean warming and acidification. PMID:21949839

Influence of Nitrogen Source on 2,4-diacetylphloroglucinol Production by the Biocontrol Strain Pf-5

OpenAIRE

M, Hultberg; B, Alsanius

2008-01-01

The production of 2,4-diacetylphloroglucinol (DAPG) by the biocontrol agent Pseudomonas fluorescens Pf-5 was studied in nutrient-solution based media with varying nitrogen content. No production of DAPG was observed when organic nitrogen was omitted from the media, regardless of the inorganic nitrogen source used. Furthermore, a micromolar concentration range of organic nitrogen was insufficient to sustain production. When a millimolar concentration range of organic nitrogen was used, DAPG pr...

Nitrogen fertilization of Cabernet Sauvignon grapevines: yield, total nitrogen content in the leaves and must composition

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Felipe Lorensini

2015-08-01

Full Text Available Grapevines grown on sandy soils are subjected to the application of supplemental nitrogen (N; however, there is little information available regarding the impact of these applications on yield, plant nutritional state and must composition. The aim of this study was to evaluate the yield, nutritional state and must composition of grapevines subjected to N fertilization. Cabernet Sauvignon grapevines were subjected to annual applications of 0, 10, 15, 20, 40, 80 and 120 kg N ha-1 in 2008, 2009 and 2010. During the 2008/09, 2009/10 and 2010/11 harvest seasons, leaves were collected during full flowering and when the berries changed color, and the total N content was analyzed. The grape yield and the enological characteristics of the must were evaluated. The response to applied N was low, and the highest Cabernet Sauvignon grape yield was obtained in response to an application of 20 kg N ha-1 year-1. The application of N increased the nutrient content in the leaf collected at full flowering, but it had little effect on the total nutrient content in the must, and it did not affect the enological characteristics of the must, such as soluble solids, pH, total acidity, malic acid and tartaric acid.

Uptake of fertilizer nitrogen and soil nitrogen by rice using 15N-labelled nitrogen fertilizer

International Nuclear Information System (INIS)

Reddy, K.R.; Patrick, W.H. Jr.

1980-01-01

Data from five field experiments using labelled nitrogen fertilizer were used to determine the relative effects of soil nitrogen and fertilizer nitrogen on rice yield. Yield of grain was closely correlated with total aboveground nitrogen uptake (soil + fertilizer), less closely correlated with soil nitrogen uptake and not significantly correlated with fertilizer nitrogen uptake. When yield increase rather than yield was correlated with fertilizer nitrogen uptake, the correlation coefficient was statistically significant. (orig.)

Protein as a sole source of nitrogen for in vitro grown tobacco plantlets

Czech Academy of Sciences Publication Activity Database

Synková, Helena; Hýsková, V.; Garčeková, K.; Křížová, S.; Ryšlavá, H.

2016-01-01

Roč. 60, č. 4 (2016), s. 635-644 ISSN 0006-3134 Institutional support: RVO:61389030 Keywords : glutamate-dehydrogenase * inorganic nitrogen * nitrate transport * organic nitrogen * amino-acids * metabolism * seedlings * leaves * roots * assimilation * ammonium * casein * chlorophyll fluorescence * nitrate * photosynthesis Subject RIV: EF - Botanics Impact factor: 1.551, year: 2016

Atmospheric Nitrogen Deposition at Two Sites in an Arid Environment of Central Asia.

Science.gov (United States)

Li, Kaihui; Liu, Xuejun; Song, Wei; Chang, Yunhua; Hu, Yukun; Tian, Changyan

2013-01-01

Arid areas play a significant role in the global nitrogen cycle. Dry and wet deposition of inorganic nitrogen (N) species were monitored at one urban (SDS) and one suburban (TFS) site at Urumqi in a semi-arid region of central Asia. Atmospheric concentrations of NH3, NO2, HNO3, particulate ammonium and nitrate (pNH4 (+) and pNO3 (-)) concentrations and NH4-N and NO3-N concentrations in precipitation showed large monthly variations and averaged 7.1, 26.6, 2.4, 6.6, 2.7 µg N m(-3) and 1.3, 1.0 mg N L(-1) at both SDS and TFS. Nitrogen dry deposition fluxes were 40.7 and 36.0 kg N ha(-1) yr(-1) while wet deposition of N fluxes were 6.0 and 8.8 kg N ha(-1) yr(-1) at SDS and TFS, respectively. Total N deposition averaged 45.8 kg N ha(-1) yr(-1)at both sites. Our results indicate that N dry deposition has been a major part of total N deposition (83.8% on average) in an arid region of central Asia. Such high N deposition implies heavy environmental pollution and an important nutrient resource in arid regions.

Nitrogen fertilization plans for the main crops of Turkey to mitigate nitrates pollution

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Theodore Karyotis

2014-01-01

Full Text Available To create a rational nitrogen fertilization plan, a mass nitrogen (N balance was used for the main crops of Turkey. The following components are included in the suggested N fertilization plans: the quantity of N fertilizer which is required by the crop for a targeted and sustainable yield, nitrogen inputs available to the crop without fertilization, nitrogen losses mainly due to nitrates leaching and emissions to the atmosphere. This simple equation was transformed to a more detailed one and fertilization plans are based on the total N required to produce a crop of a targeted yield, N mineralized from Soil Organic Matter (SOM, the residual plant available inorganic N before sowing or planting, input of nitrogen from rainfall and losses through leaching and emissions. This work is based on available data and is an open sheet balance which can be easily used by local authorities. Decreased N fertilization can be applied without significant yield reduction and this can be explained by increased N use efficiency, as a result of proper time of application and splitting of N fertilizers in doses. This model can be appropriately adapted according to site-specific conditions, whilst new parameters can be added to improve precision of the performed calculations.

Free amino nitrogen concentration correlates to total yeast assimilable nitrogen concentration in apple juice

OpenAIRE

Boudreau, Thomas F.; Peck, Gregory M.; O'Keefe, Sean F.; Stewart, Amanda C.

2017-01-01

Abstract Yeast assimilable nitrogen (YAN) is essential for yeast growth and metabolism during apple (Malus x domestica Borkh.) cider fermentation. YAN concentration and composition can impact cider fermentation kinetics and the formation of volatile aroma compounds by yeast. The YAN concentration and composition of apples grown in Virginia, USA over the course of two seasons was determined through analysis of both free amino nitrogen (FAN) and ammonium ion concentration. FAN was the largest f...

Nitrogen fixation in Red Sea seagrass meadows

KAUST Repository

Abdallah, Malak

2017-05-01

Seagrasses are key coastal ecosystems, providing many ecosystem services. Seagrasses increase biodiversity as they provide habitat for a large set of organisms. In addition, their structure provides hiding places to avoid predation. Seagrasses can grow in shallow marine coastal areas, but several factors regulate their growth and distribution. Seagrasses can uptake different kinds of organic and inorganic nutrients through their leaves and roots. Nitrogen and phosphorous are the most important nutrients for seagrass growth. Biological nitrogen fixation is the conversion of atmospheric nitrogen into ammonia by diazotrophic bacteria. This process provides a significant source of nitrogen for seagrass growth. The nitrogen fixation is controlled by the nif genes which are found in diazotrophs. The main goal of the project is to measure nitrogen fixation rates on seagrass sediments, in order to compare among various seagrass species from the Red Sea. Moreover, we will compare the fixing rates of the Vegetated areas with the bare sediments. This project will help to ascertain the role of nitrogen fixing bacteria in the development of seagrass meadows.

Uptake of organic nitrogen by plants

Science.gov (United States)

Torgny Nasholm; Knut Kielland; Ulrika. Ganeteg

2009-01-01

Languishing for many years in the shadow of plant inorganic nitrogen (N) nutrition research, studies of organic N uptake have attracted increased attention during the last decade. The capacity of plants to acquire organic N, demonstrated in laboratory and field settings, has thereby been well established. Even so, the ecological significance of organic N uptake for...

Dissolved inorganic nutrients and chlorophyll on the narrow continental shelf of Eastern Brazil

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Gilmara Fernandes Eça

2014-03-01

Full Text Available The eastern Brazilian continental shelf is narrow and subject to the influence of a western boundary current system, presenting lower biological productivity than other regions. In this study, the distribution of water masses, dissolved inorganic nutrients, chlorophyll-a and total suspended solids (TSS on the inner shelf (< 35 m depth, between Itacaré and Canavieiras, eastern Brazil, is presented. Sampling surveys were carried out in March and August 2006 and March 2007. Tropical water (TW prevailed during March 2006 and August 2007 with the lower salinity waters (< 36 found in most samples taken in March 2007, reflecting the influence of continental outflow and rain in coastal waters. Low concentrations of dissolved inorganic nutrients and Chl-a found were typical of TW and results suggested that the inner shelf waters were depleted in dissolved inorganic nitrogen in August 2006 and March 2007, and in phosphate in March 2006, potentially affecting phytoplankton growth. Stratification of the water column was observed due to differences in dissolved nutrient concentrations, chlorophyll-a and TSS when comparing surface and bottom samples, possibly the result of a colder water intrusion and mixing on the bottom shelf and a deep chlorophyll maximum and/or sediment resuspension effect. Despite this stratification, oceanographic processes such as lateral mixing driven by the Brazil Current as well as a northward alongshore drift driven by winds and tides transporting Coastal Water can lead to an enhanced mixing of these waters promoting some heterogeneity in this oligotrophic environment.

Flow analysis methods for the direct ultra-violet spectrophotometric measurement of nitrate and total nitrogen in freshwaters

Energy Technology Data Exchange (ETDEWEB)

Gentle, Brady S.; Ellis, Peter S.; Grace, Michael R. [Water Studies Centre, School of Chemistry, Monash University, Victoria 3800 (Australia); McKelvie, Ian D., E-mail: iandm@unimelb.edu.au [School of Chemistry, University of Melbourne, Victoria 3010 (Australia); School of Geography, Earth and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom)

2011-10-17

Highlights: {yields} Second derivative UV spectrophotometry has been used to determine nitrate and total N using flow analysis techniques. {yields} A simple flow system with a single-reflection flow-through cell was used for the UV measurement of nitrate. {yields} Total N was determined after on-line UV photooxidation with alkaline peroxodisulfate. {yields} Analyses carried out using the developed flow systems show a high degree of agreement with comparative analyses. {yields} This method requires no colorimetric reagents and eliminates the requirement for a toxic cadmium reduction column. - Abstract: Second derivative ultra-violet spectrophotometric methods are described for the measurement of nitrate and total nitrogen in freshwaters using flow analysis techniques. A simple flow system consisting of a peristaltic pump and a single-reflection flow-through cell was used for the measurement of nitrate. Quantification of total nitrogen using alkaline peroxodisulfate photo-digestion was achieved by incorporating an ultra-violet photo-reactor, a hollow-fibre filter and a debubbler into the flow system. The nitrate system featured a limit of detection of 0.04 mg N L{sup -1}, 0.4%RSD (1 mg N L{sup -1} as nitrate, n = 10), a coefficient of determination (R{sup 2}) of 0.9995 over the calibration range 0.0-2.0 mg N L{sup -1}, and a data acquisition time of 1.5 s per spectrum. The total nitrogen system featured a limit of detection of 0.05 mg N L{sup -1}, 1%RSD (1 mg N L{sup -1} as ammonium chloride, n = 10), a coefficient of determination of 0.9989 over the calibration range 0.0-2.0 mg N L{sup -1}, and a throughput of 5 sample h{sup -1} measured in triplicate. Digestions of five model nitrogen compounds returned recoveries of >88%. Determinations carried out using the developed systems show a high degree of agreement with data obtained using reference methods. These methods require no colorimetric reagents and eliminate the requirement for a toxic cadmium reduction column

Flow analysis methods for the direct ultra-violet spectrophotometric measurement of nitrate and total nitrogen in freshwaters

International Nuclear Information System (INIS)

Gentle, Brady S.; Ellis, Peter S.; Grace, Michael R.; McKelvie, Ian D.

2011-01-01

Highlights: → Second derivative UV spectrophotometry has been used to determine nitrate and total N using flow analysis techniques. → A simple flow system with a single-reflection flow-through cell was used for the UV measurement of nitrate. → Total N was determined after on-line UV photooxidation with alkaline peroxodisulfate. → Analyses carried out using the developed flow systems show a high degree of agreement with comparative analyses. → This method requires no colorimetric reagents and eliminates the requirement for a toxic cadmium reduction column. - Abstract: Second derivative ultra-violet spectrophotometric methods are described for the measurement of nitrate and total nitrogen in freshwaters using flow analysis techniques. A simple flow system consisting of a peristaltic pump and a single-reflection flow-through cell was used for the measurement of nitrate. Quantification of total nitrogen using alkaline peroxodisulfate photo-digestion was achieved by incorporating an ultra-violet photo-reactor, a hollow-fibre filter and a debubbler into the flow system. The nitrate system featured a limit of detection of 0.04 mg N L -1 , 0.4%RSD (1 mg N L -1 as nitrate, n = 10), a coefficient of determination (R 2 ) of 0.9995 over the calibration range 0.0-2.0 mg N L -1 , and a data acquisition time of 1.5 s per spectrum. The total nitrogen system featured a limit of detection of 0.05 mg N L -1 , 1%RSD (1 mg N L -1 as ammonium chloride, n = 10), a coefficient of determination of 0.9989 over the calibration range 0.0-2.0 mg N L -1 , and a throughput of 5 sample h -1 measured in triplicate. Digestions of five model nitrogen compounds returned recoveries of >88%. Determinations carried out using the developed systems show a high degree of agreement with data obtained using reference methods. These methods require no colorimetric reagents and eliminate the requirement for a toxic cadmium reduction column. The overlap of chloride and nitrate spectra in seawater is

Plant species richness enhances nitrogen retention in green roof plots.

Science.gov (United States)

Johnson, Catherine; Schweinhart, Shelbye; Buffam, Ishi

2016-10-01

Vegetated (green) roofs have become common in many cities and are projected to continue to increase in coverage, but little is known about the ecological properties of these engineered ecosystems. In this study, we tested the biodiversity-ecosystem function hypothesis using commercially available green roof trays as replicated plots with varying levels of plant species richness (0, 1, 3, or 6 common green roof species per plot, using plants with different functional characteristics). We estimated accumulated plant biomass near the peak of the first full growing season (July 2013) and measured runoff volume after nearly every rain event from September 2012 to September 2013 (33 events) and runoff fluxes of inorganic nutrients ammonium, nitrate, and phosphate from a subset of 10 events. We found that (1) total plant biomass increased with increasing species richness, (2) green roof plots were effective at reducing storm runoff, with vegetation increasing water retention more than soil-like substrate alone, but there was no significant effect of plant species identity or richness on runoff volume, (3) green roof substrate was a significant source of phosphate, regardless of presence/absence of plants, and (4) dissolved inorganic nitrogen (DIN = nitrate + ammonium) runoff fluxes were different among plant species and decreased significantly with increasing plant species richness. The variation in N retention was positively related to variation in plant biomass. Notably, the increased biomass and N retention with species richness in this engineered ecosystem are similar to patterns observed in published studies from grasslands and other well-studied ecosystems. We suggest that more diverse plantings on vegetated roofs may enhance the retention capacity for reactive nitrogen. This is of importance for the sustained health of vegetated roof ecosystems, which over time often experience nitrogen limitation, and is also relevant for water quality in receiving waters

Nitrogen availability from residues-based biochar at two pyrolisis temperatures

Science.gov (United States)

Coscione, Aline Renee; Silveira Bibar, Maria Paula; de Andrade, Cristiano Alberto

2014-05-01

Biochar has been studied for several applications, such as soil quality improvement, heavy metals remediation and N2O mitigation. Considering the soil quality improvement aspect it is desirable to evaluate if the nitrogen content in biochar samples obtained from several residues used as the biomass sources could be available for plants. Samples of sewage sludge (SS), coffee grounds (CG), chicken manure (CM) and fungi mycelia (FM) were pyrolyzed at two temperatures, 400 and 700 oC (indicated by the number 4 and 7 in this abstract, respectively), in order to obtain the biochar samples. The Kjeldahl nitrogen of biochar was (% m/m): 3.0 (CM4, CG7, FM7 and CG4); 2.0 (CM7 e SS4); 3.4 (FM7); 1.4 (SS7), with organic carbon (potassium dichromate method) ranging from 2.0 to 3.0% for all but CG4 (6%). The C/N ratio of biochar samples was: 9 (CM4, SS4 and CG7); 11 (CM7); 15 (SS7); 7 (FM4 and FM7); 21 (CG4). The eight soil + biochar resulting mixtures, prepared using the equivalent to 60 t/ha of biochar (about 3% w/w), and one additional control treatment (no biochar added) were incubated for 90 days, with four replications of each treatment per time evaluated. Inorganic nitrogen and soil pH measurements were performed for all treatments at 0, 5, 15, 30, 60 and 90 days of incubation. Soil moisture was kept at 40% soil water holding capacity, by weighting, during the experiment. The data was submitted to ANOVA with Tukey's average comparison test (p organic residues with C/N ratios lower than 20 applied to the soil a fast degradation, with the corresponding increase in inorganic nitrogen availability is expect. Although all the biochar samples tested had C/N ratios below that cutting point, just 2 of 8 presented inorganic nitrogen available in the soil+biochar mixtures. These results show that soil incubation tests are ultimate for the evaluation of the nitrogen potential release to the soil. Low temperature SS based biochar may offer additional nitrogen release to soil besides

Estudo da especiação de arsênio inorgânico e determinação de arsênio total no monitoramento ambiental da qualidade de águas subterrâneas Determination of total as and inorganic arsenic species for the environmental quality monitoring of groundwaters

Directory of Open Access Journals (Sweden)

Ricardo Perobelli Borba

2009-01-01

Full Text Available This work reports an alternative, fast and robust method, for the determination of total As, As(III and As(V by HG-AAS without the use of prereductants. The method is based on the different rates of arsine formation of the inorganic As species and the effect of As(III in the signal obtained for total As. Groundwater and mineral spiked waters were used to sample preservation evaluation. The method was validated by the determination of As in SRM 1640 and used in the determination of total As and its inorganic species in groundwater samples collected from mines in the Iron Quadrangle - MG.

Throughfall and fog deposition of nitrogen and sulfur at an N-limited and N-saturated site in the San Bernardino Mountains, southern California

Science.gov (United States)

Mark E. Fenn; Mark A. Poth; Susan L. Schilling; David B. Grainger

2000-01-01

Inorganic nitrogen (N) and sulfur (S) deposition in bulk throughfall and fog were determined at two sites located at opposite ends (42 km apart) of a pollution gradient in the San Bernardino Mountains. Plot-level averages for total annual N and S deposition in throughfall in 1996 were 18.8 and 2.9 kg·ha–1, respectively, at Camp Paivika (CP) and 2...

Determination of As(III) and total inorganic As in water samples using an on-line solid phase extraction and flow injection hydride generation atomic absorption spectrometry

International Nuclear Information System (INIS)

Sigrist, Mirna; Albertengo, Antonela; Beldomenico, Horacio; Tudino, Mabel

2011-01-01

A simple and robust on-line sequential injection system based on solid phase extraction (SPE) coupled to a flow injection hydride generation atomic absorption spectrometer (FI-HGAAS) with a heated quartz tube atomizer (QTA) was developed and optimized for the determination of As(III) in groundwater without any kind of sample pretreatment. The method was based on the selective retention of inorganic As(V) that was carried out by passing the filtered original sample through a cartridge containing a chloride-form strong anion exchanger. Thus the most toxic form, inorganic As(III), was determined fast and directly by AsH 3 generation using 3.5 mol L -1 HCl as carrier solution and 0.35% (m/v) NaBH 4 in 0.025% NaOH as the reductant. Since the uptake of As(V) should be interfered by several anions of natural occurrence in waters, the effect of Cl - , SO 4 2- , NO 3 - , HPO 4 2- , HCO 3 - on retention was evaluated and discussed. The total soluble inorganic arsenic concentration was determined on aliquots of filtered samples acidified with concentrated HCl and pre-reduced with 5% KI-5% C 6 H 8 O 6 solution. The concentration of As(V) was calculated by difference between the total soluble inorganic arsenic and As(III) concentrations. Detection limits (LODs) of 0.5 μg L -1 and 0.6 μg L -1 for As(III) and inorganic total As, respectively, were obtained for a 500 μL sample volume. The obtained limits of detection allowed testing the water quality according to the national and international regulations. The analytical recovery for water samples spiked with As(III) ranged between 98% and 106%. The sampling throughput for As(III) determination was 60 samples h -1 . The device for groundwater sampling was especially designed for the authors. Metallic components were avoided and the contact between the sample and the atmospheric oxygen was carried to a minimum. On-field arsenic species separation was performed through the employ of a serial connection of membrane filters and

Nitrogen concentrations in mosses indicate the spatial distribution of atmospheric nitrogen deposition in Europe

International Nuclear Information System (INIS)

Harmens, H.; Norris, D.A.; Cooper, D.M.; Mills, G.; Steinnes, E.; Kubin, E.; Thoeni, L.; Aboal, J.R.; Alber, R.; Carballeira, A.; Coskun, M.; De Temmerman, L.; Frolova, M.; Gonzalez-Miqueo, L.

2011-01-01

In 2005/6, nearly 3000 moss samples from (semi-)natural location across 16 European countries were collected for nitrogen analysis. The lowest total nitrogen concentrations in mosses ( 2 = 0.91) linear relationship was found between the total nitrogen concentration in mosses and measured site-specific bulk nitrogen deposition rates. The total nitrogen concentrations in mosses complement deposition measurements, helping to identify areas in Europe at risk from high nitrogen deposition at a high spatial resolution. - Highlights: → Nitrogen concentrations in mosses were determined at ca. 3000 sites across Europe. → Moss concentrations were compared with EMEP modelled nitrogen deposition. → The asymptotic relationship for Europe showed saturation at ca. 15 kg N ha -1 y -1 . → Linear relationships were found with measured nitrogen deposition in some countries. → Moss concentrations complement deposition measurements at high spatial resolution. - Mosses as biomonitors of atmospheric nitrogen deposition in Europe.

The first nitrogen index app for mobile devices: using portable technology for smart agricultural management

Science.gov (United States)

Nitrogen fertilizer from organic and inorganic sources is used across the world’s agroecosystems. It contributes to higher yields and higher economic returns to farmers, and is essential for food security. However, when more is applied than necessary, significant amounts of nitrogen can exit the sy...

Urea route to coat inorganic nanowires, carbon fibers and nanotubes by boron nitride

International Nuclear Information System (INIS)

Gomathi, A.; Ramya Harika, M.; Rao, C.N.R.

2008-01-01

A simple route involving urea as the nitrogen source has been employed to carry out boron nitride coating on carbon fibers, multi-walled carbon nanotubes and inorganic nanowires. The process involves heating the carbon fibers and nanotubes or inorganic nanowires in a mixture of H 3 BO 3 and urea, followed by a heat treatment at 1000 deg. C in a N 2 atmosphere. We have been able to characterize the BN coating by transmission electron microscopy as well as X-ray photoelectron spectroscopy. The urea decomposition route affords a simple method to coat boron nitride on one-dimensional nanostructures

The extent and pathways of nitrogen loss in turfgrass systems: Age impacts.

Science.gov (United States)

Chen, Huaihai; Yang, Tianyou; Xia, Qing; Bowman, Daniel; Williams, David; Walker, John T; Shi, Wei

2018-05-11

Nitrogen loss from fertilized turf has been a concern for decades, with most research focused on inorganic (NO 3 - ) leaching. The present work examined both inorganic and organic N species in leachate and soil N 2 O emissions from intact soil cores of a bermudagrass chronosequence (1, 15, 20, and 109 years old) collected in both winter and summer. Measurements of soil N 2 O emissions were made daily for 3 weeks, while leachate was sampled once a week. Four treatments were established to examine the impacts of fertilization and temperature: no N, low N at 30 kg N ha -1 , and high N at 60 kg N ha -1 , plus a combination of high N and temperature (13 °C in winter or 33 °C in summer compared to the standard 23 °C). Total reactive N loss generally showed a "cup" pattern of turf age, being lowest for the 20 years old. Averaged across all intact soil cores sampled in winter and summer, organic N leaching accounted for 51% of total reactive N loss, followed by inorganic N leaching at 41% and N 2 O-N efflux at 8%. Proportional loss among the fractions varied with grass age, season, and temperature and fertilization treatments. While high temperature enhanced total reactive N loss, it had little influence on the partitioning of loss among dissolved organic N, inorganic N and N 2 O-N when C availability was expected to be high in summer due to rhizodeposition and root turnover. This effect of temperature was perhaps due to higher microbial turnover in response to increased C availability in summer. However when C availability was low in winter, warming might mainly affect microbial growth efficiency and therefore partitioning of N. This work provides a new insight into the interactive controls of warming and substrate availability on dissolved organic N loss from turfgrass systems. Copyright © 2018 Elsevier B.V. All rights reserved.

ORGANIC CARBON AND TOTAL NITROGEN IN THE DENSIMETRIC FRACTIONS OF ORGANIC MATTER UNDER DIFFERENT SOIL MANAGEMEN

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MARCELO RIBEIRO VILELA PRADO

2016-01-01

Full Text Available The evaluation of land use and management by the measurement of soil organic matter and its fractions has gained attention since it helps in the understanding of the dynamics of their contribution to soil productivity, especially in tropical environments. This study was conducted in the municipality of Colorado do Oeste, state of Rondônia, Brazil and its aim was to determinethe quantity of organic carbon and total nitrogen in the light and heavy fractions of organic matter in the surface layers of a typic hapludalf under different land use systems: Native Forest: open evergreen forest, reference environment; Agroforestry System 1: teak (Tectona grandis LF and kudzu (Pueraria montana; Agroforestry System 2: coffee (Coffea canephora, marandu palisade grass (Brachiaria brizantha cv. Marandu, “pinho cuiabano” (Parkia multijuga, teak and kudzu.; Agroforestry System 3: teak and cocoa (Theobroma cacao; Silvopasture System: teak, cocoa and marandu palisade grass; and Extensive Grazing System: marandu palisade grass. The experimental design was a randomized block in split-split plots (use systems versus soil layers of 0-0.05 and 0.05-0.10 m with three replications. The results showed that relative to Native Forest, the Agroforestry System 2 had equal- and greater amounts of organic carbon and total nitrogen respectively (light and heavy fractions in the soil organic matter, with the light fraction being responsible for storage of approximately 45% and 70% of the organic carbon and total nitrogen, respectively. Therefore, the light densimetric fraction proved to be useful in the early identification of the general decline of the soil organic matter in the land use systems evaluated.

Leaching behavior of total organic carbon, nitrogen, and phosphorus from banana peel.

Science.gov (United States)

Jiang, Ruixue; Sun, Shujuan; Xu, Yan; Qiu, Xiudong; Yang, Jili; Li, Xiaochen

2015-01-01

The leaching behavior of organic carbon and nutrient compounds from banana peel (BP) was investigated in batch assays with respect to particle size, contact time, pH value, and temperature. The granularity, contact time, pH, and temperature caused no significant effects on the leaching of total phosphorus (TP) from the BP. The maximum leached total nitrogen (TN) content was found at pH 5.0 and 90 minutes, while no significant effects were caused by the granularity and temperature. The maximum leached total organic carbon (TOC) content was found by using a powder of 40 mesh, 150 minutes and at pH 6.0, while the temperature had no effect on the TOC leaching. The proportions of the TN, TP, and TOC contents leached from the dried BP ranged from 33.6% to 40.9%, 60.4% to 72.7%, and 8.2% to 9.9%, respectively, indicating that BP could be a potential pollution source for surface and ground water if discharged as domestic waste or reutilized without pretreatment.

Bermudagrass Management in the Southern Piedmont U.S. IV. Soil Surface Nitrogen Pools

Directory of Open Access Journals (Sweden)

Alan J. Franzluebbers

2001-01-01

Full Text Available The fate of nitrogen (N applied in forage-based agricultural systems is important for understanding the long-term production and environmental impacts of a particular management strategy. We evaluated the factorial combination of three types of N fertilization (inorganic, crimson clover [Trifolium incarnatum L.] cover crop plus inorganic, and chicken [Gallus gallus] broiler litter pressure and four types of harvest strategy (unharvested forage, low and high cattle [Bos Taurus] grazing pressure, and monthly haying in summer on surface residue and soil N pools during the first 5 years of ̒Coastal̓ bermudagrass (Cynodon dactylon [L.] Pers. management. The type of N fertilization used resulted in small changes in soil N pools, except at a depth of 0 to 2 cm, where total soil N was sequestered at a rate 0.2 g ‧ kg–1‧ year–11 greater with inorganic fertilization than with other fertilization strategies. We could account for more of the applied N under grazed systems (76–82% than under ungrazed systems (35–71%. As a percentage of applied N, 32 and 48% were sequestered as total soil N at a depth of 0 to 6 cm when averaged across fertilization strategies under low and high grazing pressures, respectively, which was equivalent to 6.8 and 10.3 g ‧ m–2 ‧ year–1. Sequestration rates of total soil N under the unharvested-forage and haying strategies were negligible. Most of the increase in total soil N was at a depth of 0 to 2 cm and was due to changes in the particulate organic N (PON pool. The greater cycling of applied N into the soil organic N pool with grazed compared with ungrazed systems suggests an increase in the long-term fertility of soil.

Mapping soil total nitrogen of cultivated land at county scale by using hyperspectral image

Science.gov (United States)

Gu, Xiaohe; Zhang, Li Yan; Shu, Meiyan; Yang, Guijun

2018-02-01

Monitoring total nitrogen content (TNC) in the soil of cultivated land quantitively and mastering its spatial distribution are helpful for crop growing, soil fertility adjustment and sustainable development of agriculture. The study aimed to develop a universal method to map total nitrogen content in soil of cultivated land by HSI image at county scale. Several mathematical transformations were used to improve the expression ability of HSI image. The correlations between soil TNC and the reflectivity and its mathematical transformations were analyzed. Then the susceptible bands and its transformations were screened to develop the optimizing model of map soil TNC in the Anping County based on the method of multiple linear regression. Results showed that the bands of 14th, 16th, 19th, 37th and 60th with different mathematical transformations were screened as susceptible bands. Differential transformation was helpful for reducing the noise interference to the diagnosis ability of the target spectrum. The determination coefficient of the first order differential of logarithmic transformation was biggest (0.505), while the RMSE was lowest. The study confirmed the first order differential of logarithm transformation as the optimal inversion model for soil TNC, which was used to map soil TNC of cultivated land in the study area.

[Prediction of total nitrogen and alkali hydrolysable nitrogen content in loess using hyperspectral data based on correlation analysis and partial least squares regression].

Science.gov (United States)

Liu, Xiu-ying; Wang, Li; Chang, Qing-rui; Wang, Xiao-xing; Shang, Yan

2015-07-01

Wuqi County of Shaanxi Province, where the vegetation recovering measures have been carried out for years, was taken as the study area. A total of 100 loess samples from 24 different profiles were collected. Total nitrogen (TN) and alkali hydrolysable nitrogen (AHN) contents of the soil samples were analyzed, and the soil samples were scanned in the visible/near-infrared (VNIR) region of 350-2500 nm in the laboratory. The calibration models were developed between TN and AHN contents and VNIR values based on correlation analysis (CA) and partial least squares regression (PLS). Independent samples validated the calibration models. The results indicated that the optimum model for predicting TN of loess was established by using first derivative of reflectance. The best model for predicting AHN of loess was established by using normal derivative spectra. The optimum TN model could effectively predict TN in loess from 0 to 40 cm, but the optimum AHN model could only roughly predict AHN at the same depth. This study provided a good method for rapidly predicting TN of loess where vegetation recovering measures have been adopted, but prediction of AHN needs to be further studied.

Total Nitrogen Deposition (wet+dry) from the Atmosphere

Data.gov (United States)

U.S. Environmental Protection Agency — Oxides of Nitrogen are emitted primarily as by-products of combustion. Sources include power plants, industrial boilers, and automobiles. In addition, agricultural...

Nitrogen dynamics model for a pilot field-scale novel dewatered alum sludge cake-based constructed wetland system.

Science.gov (United States)

Kumar, J L G; Zhao, Y Q; Hu, Y S; Babatunde, A O; Zhao, X H

2015-01-01

A model simulating the effluent nitrogen (N) concentration of treated animal farm wastewater in a pilot on-site constructed wetland (CW) system, using dewatered alum sludge cake (DASC) as wetland substrate, is presented. The N-model was developed based on the Structural Thinking Experiential Learning Laboratory with Animation software and is considering organic nitrogen, ammonia nitrogen (NH3) and nitrate nitrogen (NO3-N) as the major forms of nitrogen involved in the transformation chains. Ammonification (AMM), ammonia volatilization, nitrification (NIT), denitrification, plant uptake, plant decaying and uptake of inorganic nitrogen by algae and bacteria were considered in this model. pH, dissolved oxygen, temperature, precipitation, solar radiation and nitrogen concentrations were considered as forcing functions in the model. The model was calibrated by observed data with a reasonable agreement prior to its applications. The simulated effluent detritus nitrogen, NH4-N, NO3-N and TN had a considerably good agreement with the observed results. The mass balance analysis shows that NIT accounts for 65.60%, adsorption (ad) (11.90%), AMM (8.90%) followed by NH4-N (Plants) (5.90%) and NO3-N (Plants) (4.40%). The TN removal was found 52% of the total influent TN in the CW. This study suggested an improved overall performance of a DASC-based CW and efficient N removal from wastewater.

Analysis of a sewage sludge for inorganic chemical contaminants and nutrients

International Nuclear Information System (INIS)

Smith, R.

1984-01-01

This study forms part of the NIWR's series of interlaboratory comparison studies involving southern African laboratories engaged in water and wastewater analysis, and is concerned with the analysis by 29 laboratories of a sample of dried sewage sludge for various inorganic contaminants and nutrients by means of methods provided by the originating laboratory, the aim being to test these methods for their suitability for use in a proposed manual of methods for sewage sludge analysis. The results obtained are evaluated and discussed. From the results obtained, the suggested methods for the determination of pH, Kjeldahl, nitrogen, total phosphorus, calcium and magnesium, cadmium, chromium, copper, lead, nickel and zinc, mercury, and arsenic were considered to be sufficiently reliable for inclusion in the manual. It was recommended that further investigation be carried out on finding suitable methods for the determination of selenium, molybdenum, boron, and fluoride

40 CFR 123.45 - Noncompliance and program reporting by the Director.

Science.gov (United States)

2010-07-01

... Demand Total Oxygen Demands Total Organic Carbon Other Solids Total Suspended Solids (Residues) Total Dissolved Solids (Residues) Other Nutrients Inorganic Phosphorus Compounds Inorganic Nitrogen Compounds... develop Spill Prevention Control and Countermeasure Plans and requirements to implement Best Management...

Modelling nitrogen saturation and carbon accumulation in heathland soils under elevated nitrogen deposition

International Nuclear Information System (INIS)

Evans, C.D.; Caporn, S.J.M.; Carroll, J.A.; Pilkington, M.G.; Wilson, D.B.; Ray, N.; Cresswell, N.

2006-01-01

A simple model of nitrogen (N) saturation, based on an extension of the biogeochemical model MAGIC, has been tested at two long-running heathland N manipulation experiments. The model simulates N immobilisation as a function of organic soil C/N ratio, but permits a proportion of immobilised N to be accompanied by accumulation of soil carbon (C), slowing the rate of C/N ratio change and subsequent N saturation. The model successfully reproduced observed treatment effects on soil C and N, and inorganic N leaching, for both sites. At the C-rich upland site, N addition led to relatively small reductions in soil C/N, low inorganic N leaching, and a substantial increase in organic soil C. At the C-poor lowland site, soil C/N ratio decreases and N leaching increases were much more dramatic, and soil C accumulation predicted to be smaller. The study suggests that (i) a simple model can effectively simulate observed changes in soil and leachate N; (ii) previous model predictions based on a constant soil C pool may overpredict future N leaching; (iii) N saturation may develop most rapidly in dry, organic-poor, high-decomposition systems; and (iv) N deposition may lead to significantly enhanced soil C sequestration, particularly in wet, nutrient-poor, organic-rich systems. - Enhanced carbon sequestration may slow the rate of nitrogen saturation in heathlands

Nitrogen cycling in a flooded-soil ecosystem planted to rice (Oryza sativa L.)

International Nuclear Information System (INIS)

Reddy, K.R.

1982-01-01

15 N studies of various aspects of the nitrogen cycle in a flooded rice ecosystem on Crowley silt loam soil in Louisiana were reviewed to construct a mass balance model of the nitrogen cycle for this system. Nitrogen transformations modeled included 1) net ammonification (0.22 mg NH 4+ -N kg dry soil - 1 day - 1 ). 2) net nitrification (207 mg NO 3- -N kg dry soil - 1 day - 1 ). 3) denitrification (0.37 mg N kg dry soil - 1 day - 1 ), and 4) biological N 2 fixation (0.16 mg N kg dry soil - 1 day - 1 ). Nitrogen inputs included 1) application of fertilizers, 2) incorporation of crop residues, 3) biological N 2 fixation, and 4) deposition. Nitrogen outputs included 1) crop removal, 2) gaseous losses from NH 3 volatilization and simultaneous occurrence of nitrification-denitrification, and 3) leaching and runoff. Mass balance calculations indicated that 33% of the available inorganic nitrogen was recovered by rice, and the remaining nitrogen was lost from the system. Losses of N due to ammonia volatilization were minimal because fertilizer-N was incorporated into the soil. A significant portion of inorganic-N was lost by ammonium diffusion from the anaerobic layer to the aerobic layer in response to a concentration gradient and subsequent nitrification in the aerobic layer followed by nitrate diffusion into the anaerobic layer and denitrification into gaseous end products. Leaching and surface runoff losses were minimal. (orig.)

Reassessing carbon sequestration in the North China Plain via addition of nitrogen

Energy Technology Data Exchange (ETDEWEB)

Dong, Wenxu, E-mail: dongwx@sjziam.ac.cn [Key Laboratory of Agricultural Water Resources, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050021 (China); Duan, Yongmei, E-mail: 106086193@QQ.com [Geological Survey of Jiangxi Province, Nanchang 330030 (China); Wang, Yuying, E-mail: wangyy@sjziam.ac.cn [Key Laboratory of Agricultural Water Resources, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050021 (China); Hu, Chunsheng, E-mail: cshu@sjziam.ac.cn [Key Laboratory of Agricultural Water Resources, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050021 (China)

2016-09-01

Soil inorganic carbon (SIC) exerts a strong influence on the carbon (C) sequestered in response to nitrogen (N) additions in arid and semi-arid ecosystems, but limited information is available on in situ SIC storage and dissolution at the field level. This study determined the soil organic/inorganic carbon storage in the soil profile at 0–100 cm depths and the concentration of dissolved inorganic carbon (DIC) in soil leachate in 4 N application treatments (0, 200, 400, and 600 kg N ha{sup −1} yr{sup −1}) for 15 years in the North China Plain. The objectives were to evaluate the effect of nitrogen fertilizer on total amount of carbon sequestration and the uptake of atmospheric CO{sub 2} in an agricultural system. Results showed that after 15 years of N fertilizer application the SOC contents at depths of 0–100 cm significantly increased, whereas the SIC contents significantly decreased at depths of 0–60 cm. However, the actual measured loss of carbonate was far higher than the theoretical maximum values of dissolution via protons from nitrification. Furthermore, the amount of HCO{sub 3}{sup −} and the HCO{sub 3}{sup −} / (Ca{sup 2+} + Mg{sup 2+}) ratio in soil leachate were higher in the N application treatments than no fertilizer input (CK) for the 0–80 cm depth. The result suggested that the dissolution of carbonate was mainly enhanced by soil carbonic acid, a process which can absorb soil or atmosphere CO{sub 2} and less influenced by protons through the nitrification which would release CO{sub 2}. To accurately evaluate soil C sequestration under N input scenarios in semi-arid regions, future studies should include both changes in SIC storage as well as the fractions of dissolution with different sources of acids in soil profiles. - Highlights: • The SOC contents significantly increased after long-term nitrogen application, while SIC decreased. • The measured loss of carbonate was far higher than the theoretical values of dissolution from

Atmospheric nitrogen deposition in the Yangtze River basin: Spatial pattern and source attribution

International Nuclear Information System (INIS)

Xu, Wen; Zhao, Yuanhong; Liu, Xuejun; Dore, Anthony J.; Zhang, Lin; Liu, Lei; Cheng, Miaomiao

2018-01-01

The Yangtze River basin is one of the world's hotspots for nitrogen (N) deposition and likely plays an important role in China's riverine N output. Here we constructed a basin-scale total dissolved inorganic N (DIN) deposition (bulk plus dry) pattern based on published data at 100 observational sites between 2000 and 2014, and assessed the relative contributions of different reactive N (N r ) emission sectors to total DIN deposition using the GEOS-Chem model. Our results show a significant spatial variation in total DIN deposition across the Yangtze River basin (33.2 kg N ha −1 yr −1 on average), with the highest fluxes occurring mainly in the central basin (e.g., Sichuan, Hubei and Hunan provinces, and Chongqing municipality). This indicates that controlling N deposition should build on mitigation strategies according to local conditions, namely, implementation of stricter control of N r emissions in N deposition hotspots but moderate control in the areas with low N deposition levels. Total DIN deposition in approximately 82% of the basin area exceeded the critical load of N deposition for semi-natural ecosystems along the basin. On the basin scale, the dominant source of DIN deposition is fertilizer use (40%) relative to livestock (11%), industry (13%), power plant (9%), transportation (9%), and others (18%, which is the sum of contributions from human waste, residential activities, soil, lighting and biomass burning), suggesting that reducing NH 3 emissions from improper fertilizer (including chemical and organic fertilizer) application should be a priority in curbing N deposition. This, together with distinct spatial variations in emission sector contributions to total DIN deposition also suggest that, in addition to fertilizer, major emission sectors in different regions of the basin should be considered when developing synergistic control measures. - Highlights: • Total DIN deposition fluxes showed a significant spatial variation in the

Modeling the inorganic bromine partitioning in the tropical tropopause layer over the eastern and western Pacific Ocean

Directory of Open Access Journals (Sweden)

M. A. Navarro

2017-08-01

Full Text Available The stratospheric inorganic bromine (Bry burden arising from the degradation of brominated very short-lived organic substances (VSLorg and its partitioning between reactive and reservoir species is needed for a comprehensive assessment of the ozone depletion potential of brominated trace gases. Here we present modeled inorganic bromine abundances over the Pacific tropical tropopause based on aircraft observations of VSLorg from two campaigns of the Airborne Tropical TRopopause EXperiment (ATTREX 2013, carried out over the eastern Pacific, and ATTREX 2014, carried out over the western Pacific and chemistry-climate simulations (along ATTREX flight tracks using the specific meteorology prevailing. Using the Community Atmosphere Model with Chemistry (CAM-Chem we model that BrO and Br are the daytime dominant species. Integrated across all ATTREX flights, BrO represents ∼ 43 and 48 % of daytime Bry abundance at 17 km over the western and eastern Pacific, respectively. The results also show zones where Br / BrO > 1 depending on the solar zenith angle (SZA, ozone concentration, and temperature. On the other hand, BrCl and BrONO2 were found to be the dominant nighttime species with ∼  61 and 56 % of abundance at 17 km over the western and eastern Pacific, respectively. The western-to-eastern differences in the partitioning of inorganic bromine are explained by different abundances of ozone (O3, nitrogen dioxide (NO2, total inorganic chlorine (Cly, and the efficiency of heterogeneous reactions of bromine reservoirs (mostly BrONO2 and HBr occurring on ice crystals.

Modelling inorganic nitrogen in runoff: Seasonal dynamics at four European catchments as simulated by the MAGIC model.

Science.gov (United States)

Oulehle, F; Cosby, B J; Austnes, K; Evans, C D; Hruška, J; Kopáček, J; Moldan, F; Wright, R F

2015-12-01

Nitrogen (N) deposition is globally considered as a major threat to ecosystem functioning with important consequences for biodiversity, carbon sequestration and N retention. Lowered N retention as manifested by elevated concentrations of inorganic N in surface waters indicates ecosystem N saturation. Nitrate (NO3) concentrations in runoff from semi-natural catchments typically show an annual cycle, with low concentrations during the summer and high concentrations during the winter. Process-oriented catchment-scale biogeochemical models provide tools for simulation and testing changes in surface water and soil chemistry in response to changes in sulphur (S) and N deposition and climate. Here we examine the ability of MAGIC to simulate the observed monthly as well as the long-term trends over 10-35 years of inorganic N concentrations in streamwaters from four monitored headwater catchments in Europe: Čertovo Lake in the Czech Republic, Afon Gwy at Plynlimon, UK, Storgama, Norway and G2 NITREX at Gårdsjön, Sweden. The balance between N inputs (mineralization+deposition) and microbial immobilization and plant uptake defined the seasonal pattern of NO3 leaching. N mineralization and N uptake were assumed to be governed by temperature, described by Q10 functions. Seasonality in NO3 concentration and fluxes were satisfactorily reproduced at three sites (R2 of predicted vs. modelled concentrations varied between 0.32 and 0.47 and for fluxes between 0.36 and 0.88). The model was less successful in reproducing the observed NO3 concentrations and fluxes at the experimental N addition site G2 NITREX (R2=0.01 and R2=0.19, respectively). In contrast to the three monitored sites, Gårdsjön is in a state of change from a N-limited to N-rich ecosystem due to 20 years of experimental N addition. At Gårdsjön the measured NO3 seasonal pattern did not follow typical annual cycle for reasons which are not well understood, and thus not simulated by the model. The MAGIC model is

Determination of As(III) and total inorganic As in water samples using an on-line solid phase extraction and flow injection hydride generation atomic absorption spectrometry

Energy Technology Data Exchange (ETDEWEB)

Sigrist, Mirna, E-mail: msigrist@fiq.unl.edu.ar [Laboratorio Central, Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santiago del Estero 2654-Piso 6, (3000) Santa Fe (Argentina); Albertengo, Antonela; Beldomenico, Horacio [Laboratorio Central, Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santiago del Estero 2654-Piso 6, (3000) Santa Fe (Argentina); Tudino, Mabel [Laboratorio de Analisis de Trazas, Departamento de Quimica Inorganica, Analitica y Quimica Fisica/INQUIMAE, Facultad de Ciencias Exactas y Naturales, Pabellon II, Ciudad Universitaria (1428), Buenos Aires (Argentina)

2011-04-15

A simple and robust on-line sequential injection system based on solid phase extraction (SPE) coupled to a flow injection hydride generation atomic absorption spectrometer (FI-HGAAS) with a heated quartz tube atomizer (QTA) was developed and optimized for the determination of As(III) in groundwater without any kind of sample pretreatment. The method was based on the selective retention of inorganic As(V) that was carried out by passing the filtered original sample through a cartridge containing a chloride-form strong anion exchanger. Thus the most toxic form, inorganic As(III), was determined fast and directly by AsH{sub 3} generation using 3.5 mol L{sup -1} HCl as carrier solution and 0.35% (m/v) NaBH{sub 4} in 0.025% NaOH as the reductant. Since the uptake of As(V) should be interfered by several anions of natural occurrence in waters, the effect of Cl{sup -}, SO{sub 4}{sup 2-}, NO{sub 3}{sup -}, HPO{sub 4}{sup 2-}, HCO{sub 3}{sup -} on retention was evaluated and discussed. The total soluble inorganic arsenic concentration was determined on aliquots of filtered samples acidified with concentrated HCl and pre-reduced with 5% KI-5% C{sub 6}H{sub 8}O{sub 6} solution. The concentration of As(V) was calculated by difference between the total soluble inorganic arsenic and As(III) concentrations. Detection limits (LODs) of 0.5 {mu}g L{sup -1} and 0.6 {mu}g L{sup -1} for As(III) and inorganic total As, respectively, were obtained for a 500 {mu}L sample volume. The obtained limits of detection allowed testing the water quality according to the national and international regulations. The analytical recovery for water samples spiked with As(III) ranged between 98% and 106%. The sampling throughput for As(III) determination was 60 samples h{sup -1}. The device for groundwater sampling was especially designed for the authors. Metallic components were avoided and the contact between the sample and the atmospheric oxygen was carried to a minimum. On-field arsenic species

Organic carbon source and C/N ratio affect inorganic nitrogen profile in the biofloc-based culture media of Pacific white shrimp (Litopenaeus vannamei

Directory of Open Access Journals (Sweden)

Muhammad Hanif Azhar

2016-03-01

Full Text Available Organic carbon source and C/N ratio play an important role in aquaculture system with biofloc technology application. Nitrogen control by adding carbohydrates to the water to stimulate heterotrophic bacterial growth by converting nitrogen into bacterial biomass. The study investigated the effect molasses, tapioca, tapioca by product and rice bran as carbon sources in a biofloc media at three different C/N ratios i.e. 10, 15, and 20 on total ammonia reduction in biofloc media. Five liters of biofloc media in a conical tank was prepared for each replicate, which consisted of 500 mL of biofloc suspension collected from a shrimp culture unit with biofloc technology application and 4.5 L seawater. Pacific white shrimp culture was performed in 40L glass aquaria at a shrimp density of 30/aquarium. There was a significant interaction between carbon source and the C/N ratio applied (P<0.05. The use of molasses resulted in the highest reduction rate irrespective to the C/N ratio. Keywords: molasses, tapioca, tapioca by product, rice bran, biofloc, total ammonia nitrogen

Bulk deposition of organic and inorganic nitrogen in southwest China from 2008 to 2013.

Science.gov (United States)

Song, Ling; Kuang, Fuhong; Skiba, Ute; Zhu, Bo; Liu, Xuejun; Levy, Peter; Dore, Anthony; Fowler, David

2017-08-01

China is regarded as one of the nitrogen deposition hotspots in the world. Measurements to-date have focused mainly on the North China Plain, ignoring the fact that atmospheric chemical and physical properties vary across the country and that there may be other hotspots regions that should be investigated. For this reason we have conducted a six year study, measuring the bulk deposition of reduced (NH 4 -N), oxidized (NO 3 -N), and dissolved organic nitrogen (DON) at three contrasting sites in the Sichuan province, southwest China. The study sites were a high altitude forest in the Gongga Mountains (GG), an agriculture dominated region in Yanting (YT) and an urban site in the mega city Chengdu (CD). The annual average bulk deposition fluxes of total dissolved nitrogen (TDN) were 7.4, 23.1 and 36.6 kg N ha -1 yr -1 at GG, YT and CD sites, respectively, during the study period 2008 to 2013. The contributions of NH 4 -N, NO 3 -N and DON to the TDN were in the range of 48.4-57.8%, 28.8-43.7%, and 8.0-15.6%, respectively. DON bulk deposition was mainly dominated by agricultural activities. TDN bulk deposition fluxes showed increasing trends at the agricultural and urban sites from 2008 to 2013, but there was little change at the remote forest (GG) site. While reduced N dominated bulk N deposition at all the three sites, its contribution showed a decreasing trend, suggesting a gradual increase in the importance of oxidized N. These results reveal the value of long term monitoring in detecting changes in the atmospheric chemical composition of this rapidly changing region, and their inclusion in the policy debate regarding which sources should be controlled in order to reduce the long term impacts of N deposition, especially for southwest China, where there are few measurements of N deposition. Copyright © 2017 Elsevier Ltd. All rights reserved.

Anammox revisited: thermodynamic considerations in early studies of the microbial nitrogen cycle.

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Oren, Aharon

2015-08-01

This paper explores the early literature on the thermodynamics of processes in the microbial nitrogen cycle, evaluating parameters of transfer of energy which depends on the initial and final states of the system, the mechanism of the reactions involved and the rates of these reactions. Processes discussed include the anaerobic oxidation of ammonium (the anammox reaction), the use of inorganic nitrogen compounds as electron donors for anoxygenic photosynthesis, and the mechanism and bioenergetics of biological nitrogen fixation. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Organic-inorganic hybrid carbon dots for cell imaging

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Liu, Huan; Zhang, Hongwen; Li, Jiayu; Tang, Yuying; Cao, Yu; Jiang, Yan

2018-04-01

In this paper, nitrogen-doped carbon dots (CDs) had been synthesized directly by one-step ultrasonic treatment under mild conditions. During the functionalization process, Octa-aminopropyl polyhedral oligomeric silsesquioxane hydrochloride salt (OA-POSS) was used as stabilizing and passivation agent, which lead to self-assembling of CDs in aqueous medium solution. OA-POSS was obtained via hydrolytic condensation of γ-aminopropyl triethoxy silane (APTES). The average size of CDs prepared was approximately 3.3 nm with distribution between 2.5 nm and 4.5 nm. The prepared organic-inorganic hybrid carbon dots have several characteristics such as photoluminescence emission wavelength, efficient cellular uptake, and good biocompatibility. The results indicate that OA-POSS can maintain the fluorescence properties of the carbon dots effectively, and reduced cytotoxicity provides the possibility for biomedical applications. More than 89% of the Hela cells were viable when incubated with 2 mg ml‑1 or lesser organic-inorganic hybrid carbon dots. Thus, it provides a potential for multicolor imaging with HeLa cells.

Fluxes of total reactive atmospheric nitrogen (ΣNr using eddy covariance above arable land

Directory of Open Access Journals (Sweden)

Christophe R. Flechard

2013-02-01

Full Text Available The amount and timing of reactive nitrogen exchange between agricultural land and the atmosphere play a key role in evaluating ecosystem productivity and in addressing atmospheric nitrogen budgets and transport. With the recent development of the Total Reactive Atmospheric Nitrogen Converter (TRANC apparatus, a methodology has been provided for continuous measurement of the sum of all airborne nitrogen containing species (ΣNr allowing for diurnal and seasonal investigations. We present ΣNr concentration and net flux data from an 11-month field campaign conducted at an arable field using the TRANC system within an eddy-covariance setup. Clear diurnal patterns of both ΣNr concentrations and fluxes with significant dependencies on atmospheric stability and stomatal regulation were observed in the growing season. TRANC data were compared with monthly-averaged concentrations and dry deposition rates of selected Nr compounds using DELTA denuders and ensemble-averages of four inferential models, respectively. Similar seasonal trends were found for Nr concentrations from DELTA and TRANC measurements with values from the latter being considerably higher than those of DELTA denuders. The variability of the difference between these two systems could be explained by seasonally changing source locations of NOx contributions to the TRANC signal. As soil and vegetation Nr emissions to the atmosphere are generally not treated by inferential (dry deposition models, TRANC data showed lower monthly deposition rates than those obtained from inferential modelling. Net ΣNr exchange was almost neutral (~0.072 kg N ha−1 at the end of the observation period. However, during most parts of the year, slight but permanent net ΣNr deposition was found. Our measurements demonstrate that fertilizer addition followed by substantial ΣNr emissions plays a crucial role in a site's annual atmospheric nitrogen budget. As long-term Nr measurements with high temporal

Atmospheric Inputs of Nitrogen, Carbon, and Phosphorus across an Urban Area: Unaccounted Fluxes and Canopy Influences

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Decina, Stephen M.; Templer, Pamela H.; Hutyra, Lucy R.

2018-02-01

Rates of atmospheric deposition are declining across the United States, yet urban areas remain hotspots of atmospheric deposition. While past studies show elevated rates of inorganic nitrogen (N) deposition in cities, less is known about atmospheric inputs of organic N, organic carbon (C), and organic and inorganic phosphorus (P), all of which can affect ecosystem processes, water quality, and air quality. Further, the effect of the tree canopy on amounts and forms of nutrients reaching urban ground surfaces is not well-characterized. We measured growing season rates of total N, organic C, and total P in bulk atmospheric inputs, throughfall, and soil solution around the greater Boston area. We found that organic N constitutes a third of total N inputs, organic C inputs are comparable to rural inputs, and inorganic P inputs are 1.2 times higher than those in sewage effluent. Atmospheric inputs are enhanced two-to-eight times in late spring and are elevated beneath tree canopies, suggesting that trees augment atmospheric inputs to ground surfaces. Additionally, throughfall inputs may directly enter runoff when trees extend above impervious surfaces, as is the case with 26.1% of Boston's tree canopy. Our results indicate that the urban atmosphere is a significant source of elemental inputs that may impact urban ecosystems and efforts to improve water quality, particularly in terms of P. Further, as cities create policies encouraging tree planting to provide ecosystem services, locating trees above permeable surfaces to reduce runoff nutrient loads may be essential to managing urban biogeochemical cycling and water quality.

Influence of nitrogen sources on amino acid production by aspergillus niger

International Nuclear Information System (INIS)

Almani, F.; Dahot, M.U.

2007-01-01

The effect of different organic and inorganic nitrogen sources in 0.1% and 0.2% concentration on the production of amino acid was studied using a wild strain of Aspergillus niger. The rate of amino acid biosynthesis was found to be higher when 0.2% corn steep liquor was incorporated in the mineral medium. It was concluded from the study that the amino acid synthesis by wild strain depends not only on the nature and type of nitrogen sources used but the concentration of nitrogen source also play an important in the accumulation of free amino acids in the medium. (author)

The nitrogen cycle on Mars

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Mancinelli, Rocco L.

1989-01-01

Nirtogen is an essential element for the evolution of life, because it is found in a variety of biologically important molecules. Therefore, N is an important element to study from a exobiological perspective. In particular, fixed nitrogen is the biologically useful form of nitrogen. Fixed nitrogen is generally defines as NH3, NH4(+), NO(x), or N that is chemically bound to either inorganic or organic molecules, and releasable by hydrolysis to NH3 or NH4(+). On Earth, the vast majority of nitrogen exists as N2 in the atmosphere, and not in the fixes form. On early Mars the same situations probably existed. The partial pressure of N2 on early Mars was thought to be 18 mb, significantly less than that of Earth. Dinitrogen can be fixed abiotically by several mechanisms. These mechanisms include thernal shock from meteoritic infall and lightning, as well as the interaction of light and sand containing TiO2 which produces NH3 that would be rapidly destroyed by photolysis and reaction with OH radicals. These mechanisms could have been operative on primitive Mars.The chemical processes effecting these compounds and possible ways of fixing or burying N in the Martian environment are described. Data gathered in this laboratory suggest that the low abundance of nitrogen along (compared to primitive Earth) may not significantly deter the origin and early evolution of a nitrogen utilizing organisms. However, the conditions on current Mars with respect to nitrogen are quite different, and organisms may not be able to utilize all of the available nitrogen.

Inorganic aerosols responses to emission changes in Yangtze River Delta, China.

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Dong, Xinyi; Li, Juan; Fu, Joshua S; Gao, Yang; Huang, Kan; Zhuang, Guoshun

2014-05-15

The new Chinese National Ambient Air Quality standards (CH-NAAQS) published on Feb. 29th, 2012 listed PM2.5 as criteria pollutant for the very first time. In order to probe into PM2.5 pollution over Yangtze River Delta, the integrated MM5/CMAQ modeling system is applied for a full year simulation to examine the PM2.5 concentration and seasonality, and also the inorganic aerosols responses to precursor emission changes. Total PM2.5 concentration over YRD was found to have strong seasonal variation with higher values in winter months (up to 89.9 μg/m(3) in January) and lower values in summer months (down to 28.8 μg/m(3) in July). Inorganic aerosols were found to have substantial contribution to PM2.5 over YRD, ranging from 37.1% in November to 52.8% in May. Nocturnal production of nitrate (NO3(-)) through heterogeneous hydrolysis of N2O5 was found significantly contribute to high NO3(-) concentration throughout the year. In winter, NO3(-) was found to increase under nitrogen oxides (NOx) emission reduction due to higher production of N2O5 from the excessive ozone (O3) introduced by attenuated titration, which further lead to increase of ammonium (NH4(+)) and sulfate (SO4(2-)), while other seasons showed decrease response of NO3(-). Sensitivity responses of NO3(-) under anthropogenic VOC emission reduction was examined and demonstrated that in urban areas over YRD, NO3(-) formation was actually more sensitive to VOC than NOx due to the O3-involved nighttime chemistry of N2O5, while a reduction of NOx emission may have counter-intuitive effect by increasing concentrations of inorganic aerosols. Copyright © 2014 Elsevier B.V. All rights reserved.

Distribution of total nitrogen and N-15 labelled nitrogen applied to apple trees

International Nuclear Information System (INIS)

Calvache, Marcelo.

1990-01-01

The efficiency of nitrogen fertilization from one year's application was studied in apple trees. Urea enriched with 1,5% N-15 a.e. was applied to 2 years old apple trees. Two irrigation treatments were studied, Al approx. 200mm/week and A2 approx. 100 mm/week. The distribution of N in the different parts of the trees was determined after 2 months of fertilization and after the experimental trees were excavated. The recovery of labelled fertilizer N was different in the trees in both treatments (Al = 1,2% and A2 = 3,1%). However, the distribution in the tree's parts was similar: 46% in leaves, 34% in branches and 20% in roots. We also determined that sampling only 20% of leaves at the beginning and the end of the experiment it is possible to know the quantity of nitrogen from fertilizer, without the excavation trees

Total Mercury, Methylmercury, Inorganic Arsenic and Other Elements in Meat from Minke Whale (Balaenoptera acutorostrata) from the North East Atlantic Ocean.

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Maage, Amund; Nilsen, Bente M; Julshamn, Kaare; Frøyland, Livar; Valdersnes, Stig

2017-08-01

Meat samples of 84 minke whales (Balaenoptera acutorostrata) mainly from the Barents Sea, collected between 1 May and 16 August 2011, were analyzed for total mercury, methylmercury, cadmium, lead, total arsenic, inorganic arsenic and selenium. The average total mercury concentration found was 0.15 ± 0.09 mg/kg, with a range from 0.05 to 0.49 mg/kg. The molar ratio of selenium to mercury varied between 1.0 and 10.3. Cadmium content ranged from 0.002 to 0.036 mg/kg, while the content of lead in whale meat ranged from whale samples exceeded established EU maximum levels for metals in fish muscle, but 4.8% and 6.8% of the samples exceeded Japanese maximum levels for total mercury and methylmercury, respectively, in whale meat. There was only minor variations in element concentrations between whales from different geographical areas, and cadmium was the only element were the concentration increased with increasing length.

Nitrogen concentrations in mosses indicate the spatial distribution of atmospheric nitrogen deposition in Europe

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Harmens, H., E-mail: hh@ceh.ac.uk [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Norris, D.A., E-mail: danor@ceh.ac.uk [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Cooper, D.M., E-mail: cooper@ceh.ac.uk [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Mills, G., E-mail: gmi@ceh.ac.uk [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Steinnes, E., E-mail: Eiliv.Steinnes@chem.ntnu.no [Department of Chemistry, Norwegian University of Science and Technology, 7491 Trondheim (Norway); Kubin, E., E-mail: Eero.Kubin@metla.fi [Finnish Forest Research Institute, Kirkkosaarentie 7, 91500 Muhos (Finland); Thoeni, L., E-mail: lotti.thoeni@fub-ag.ch [FUB-Research Group for Environmental Monitoring, Alte Jonastrasse 83, 8640 Rapperswil (Switzerland); Aboal, J.R., E-mail: jesusramon.aboal@usc.es [University of Santiago de Compostela, Faculty of Biology, Department of Ecology, 15782 Santiago de Compostela (Spain); Alber, R., E-mail: Renate.Alber@provinz.bz.it [Environmental Agency of Bolzano, 39055 Laives (Italy); Carballeira, A., E-mail: alejo.carballeira@usc.es [University of Santiago de Compostela, Faculty of Biology, Department of Ecology, 15782 Santiago de Compostela (Spain); Coskun, M., E-mail: coskunafm@yahoo.com [Canakkale Onsekiz Mart University, Faculty of Medicine, Department of Medical Biology, 17100 Canakkale (Turkey); De Temmerman, L., E-mail: ludet@var.fgov.be [Veterinary and Agrochemical Research Centre, Tervuren (Belgium); Frolova, M., E-mail: marina.frolova@lvgma.gov.lv [Latvian Environment, Geology and Meteorology Agency, Riga (Latvia); Gonzalez-Miqueo, L., E-mail: lgonzale2@alumni.unav.es [Univ. of Navarra, Irunlarrea No 1, 31008 Pamplona (Spain)

2011-10-15

In 2005/6, nearly 3000 moss samples from (semi-)natural location across 16 European countries were collected for nitrogen analysis. The lowest total nitrogen concentrations in mosses (<0.8%) were observed in northern Finland and northern UK. The highest concentrations ({>=}1.6%) were found in parts of Belgium, France, Germany, Slovakia, Slovenia and Bulgaria. The asymptotic relationship between the nitrogen concentrations in mosses and EMEP modelled nitrogen deposition (averaged per 50 km x 50 km grid) across Europe showed less scatter when there were at least five moss sampling sites per grid. Factors potentially contributing to the scatter are discussed. In Switzerland, a strong (r{sup 2} = 0.91) linear relationship was found between the total nitrogen concentration in mosses and measured site-specific bulk nitrogen deposition rates. The total nitrogen concentrations in mosses complement deposition measurements, helping to identify areas in Europe at risk from high nitrogen deposition at a high spatial resolution. - Highlights: > Nitrogen concentrations in mosses were determined at ca. 3000 sites across Europe. > Moss concentrations were compared with EMEP modelled nitrogen deposition. > The asymptotic relationship for Europe showed saturation at ca. 15 kg N ha{sup -1} y{sup -1}. > Linear relationships were found with measured nitrogen deposition in some countries. > Moss concentrations complement deposition measurements at high spatial resolution. - Mosses as biomonitors of atmospheric nitrogen deposition in Europe.

Using SPAD-502 to evaluate the total chlorophyll and nitrogen status in leaves of longkong (Aglaia dookkoo Griff. and rambutan (Nephelium lappaseum L.

Directory of Open Access Journals (Sweden)

Chanaweerawan, S.

2002-01-01

Full Text Available Total chlorophyll and nitrogen status in leaves of longkong and rambutan were evaluated by using the SPAD-502 meter. Leaves of both species were sampled from 10 year-old trees grown in an experimental plot at Prince of Songkla University, Hat Yai campus. The relationship between SPAD-502 meter reading (SPAD and total chlorophyll content analyzed in the laboratory was evaluated in longkong and rambutan, and they were y = -2.68+0.21x, r2 = 0.77** and y = -1.11+0.18x, r2 = 0.77**, respectively. The data recorded by SPAD were also linearly related in a positive manner to nitrogen status in longkong (y = 1.27+0.20x, r2 = 0.82** and rambutan (y = 1.17+0.02x, r2 = 0.79**. The results show that using the SPAD-502 meter is convenient and fast for the evaluation of total chlorophyll and nitrogen status in leaves of longkong and rambutan.

Organics and nitrogen removal from textile auxiliaries wastewater with A2O-MBR in a pilot-scale

International Nuclear Information System (INIS)

Sun, Faqian; Sun, Bin; Hu, Jian; He, Yangyang; Wu, Weixiang

2015-01-01

Highlights: • A pilot-scale A 2 O-MBR system treating textile auxiliaries wastewater was assessed. • Organic matter and recycle ratio strongly affected the performance of the system. • GC/MS analysis found some refractory organics in the MBR permeate. • Combination of organic foulants and inorganic compounds caused membrane fouling. - Abstract: The removal of organic compounds and nitrogen in an anaerobic–anoxic–aerobic membrane bioreactor process (A 2 O-MBR) for treatment of textile auxiliaries (TA) wastewater was investigated. The results show that the average effluent concentrations of chemical oxygen demand (COD), ammonium nitrogen (NH 4 + –N) and total nitrogen (TN) were about 119, 3 and 48 mg/L under an internal recycle ratio of 1.5. The average removal efficiency of COD, NH 4 + –N and TN were 87%, 96% and 55%, respectively. Gas chromatograph–mass spectrometer analysis indicated that, although as much as 121 different types of organic compounds were present in the TA wastewater, only 20 kinds of refractory organic compounds were found in the MBR effluent, which could be used as indicators of effluents from this kind of industrial wastewater. Scanning electron microscopy analysis revealed that bacterial foulants were significant contributors to membrane fouling. An examination of foulants components by wavelength dispersive X-ray fluorescence showed that the combination of organic foulants and inorganic compounds enhanced the formation of gel layer and thus caused membrane fouling. The results will provide valuable information for optimizing the design and operation of wastewater treatment system in the textile industry

Seasonal changes in amino acids, protein and total nitrogen in needles of fertilized Scots pine trees.

Science.gov (United States)

Näsholm, T; Ericsson, A

1990-09-01

Seasonal changes in amino acids, protein and total nitrogen in needles of 30-year-old, fertilized Scots pine (Pinus sylvestris L.) trees growing in Northern Sweden were investigated over two years in field experiments. The studied plots had been fertilized annually for 17 years with (i) a high level of N, (ii) a medium level of N, or (iii) a medium level of N, P and K. Trees growing on unfertilized plots served as controls. In control trees, glutamine, glutamic acid, gamma-aminobutyric acid, aspartic acid and proline represented 50-70% of the total free amino acids determined. Arginine was present only in low concentrations in control trees throughout the year, but it was usually the most abundant amino acid in fertilized trees. Glutamine concentrations were high during the spring and summer in both years of study, whereas proline concentrations were high in the spring but otherwise low throughout the year. In the first year of study, glutamic acid concentrations were high during the spring and summer, whereas gamma-aminobutyric acid was present in high concentrations during the winter months. This pattern was less pronounced in the second year of investigation. The concentrations of most amino acids, except glutamic acid, increased in response to fertilization. Nitrogen fertilization increased the foliar concentration of arginine from trees to a maximum of 110 micromol g(dw) (-1). Trees fertilized with nitrogen, phosphorus and potassium had significantly lower arginine concentrations than trees fertilized with the same amount of nitrogen only. Protein concentrations were similar in all fertilized trees but higher than those in control trees. For all treatments, protein concentrations were high in winter and at a minimum in early spring. In summer, the protein concentration remained almost constant except for a temporary decrease which coincided with the expansion of new shoots. Apart from arginine, the amino acid composition of proteins was similar in all

Nitrogen fate in a subtropical mangrove swamp: Potential association with seawater-groundwater exchange.

Science.gov (United States)

Xiao, Kai; Wu, Jiapeng; Li, Hailong; Hong, Yiguo; Wilson, Alicia M; Jiao, Jiu Jimmy; Shananan, Meghan

2018-04-18

Coastal mangrove swamps play an important role in nutrient cycling at the land-ocean boundary. However, little is known about the role of periodic seawater-groundwater exchange in the nitrogen cycling processes. Seawater-groundwater exchange rates and inorganic nitrogen concentrations were investigated along a shore-perpendicular intertidal transect in Daya Bay, China. The intertidal transect comprises three hydrologic subzones (tidal creek, mangrove and bare mudflat zones), each with different physicochemical characteristics. Salinity and hydraulic head measurements taken along the transect were used to estimate the exchange rates between seawater and groundwater over a spring-neap tidal cycle. Results showed that the maximum seawater-groundwater exchange occurred within the tidal creek zone, which facilitated high-oxygen seawater infiltration and subsequent nitrification. In contrast, the lowest exchange rate found in the mangrove zone caused over-loading of organic matter and longer groundwater residence times. This created an anoxic environment conducive to nitrogen loss through the anammox and denitrification processes. Potential oxidation rates of ammonia and nitrite were measured by the rapid and high-throughput method and rates of denitrification and anammox were measured by the modified membrane inlet mass spectrometry (MIMS) with isotope pairing, respectively. In the whole transect, denitrification accounted for 90% of the total nitrogen loss, and anammox accounted for the remaining 10%. The average nitrogen removal rate was about 2.07g per day per cubic meter of mangrove sediments. Copyright © 2018 Elsevier B.V. All rights reserved.

Spectral measurements at different spatial scales in potato: relating leaf, plant and canopy nitrogen status

Science.gov (United States)

Jongschaap, Raymond E. E.; Booij, Remmie

2004-09-01

Chlorophyll contents in vegetation depend on soil nitrogen availability and on crop nitrogen uptake, which are important management factors in arable farming. Crop nitrogen uptake is important, as nitrogen is needed for chlorophyll formation, which is important for photosynthesis, i.e. the conversion of absorbed radiance into plant biomass. The objective of this study was to estimate leaf and canopy nitrogen contents by near and remote sensing observations and to link observations at leaf, plant and canopy level. A theoretical base is presented for scaling-up leaf optical properties to whole plants and crops, by linking different optical recording techniques at leaf, plant and canopy levels through the integration of vertical nitrogen distribution. Field data come from potato experiments in The Netherlands in 1997 and 1998, comprising two potato varieties: Eersteling and Bintje, receiving similar nitrogen treatments (0, 100, 200 and 300 kg N ha -1) in varying application schemes to create differences in canopy nitrogen status during the growing season. Ten standard destructive field samplings were performed to follow leaf area index and crop dry weight evolution. Samples were analysed for inorganic nitrogen and total nitrogen contents. At sampling dates, spectral measurements were taken both at leaf level and at canopy level. At leaf level, an exponential relation between SPAD-502 readings and leaf organic nitrogen contents with a high correlation factor of 0.91 was found. At canopy level, an exponential relation between canopy organic nitrogen contents and red edge position ( λrep, nm) derived from reflectance measurements was found with a good correlation of 0.82. Spectral measurements (SPAD-502) at leaf level of a few square mm were related to canopy reflectance measurements (CropScan™) of approximately 0.44 m 2. Statistical regression techniques were used to optimise theoretical vertical nitrogen profiles that allowed scaling-up leaf chlorophyll measurements

Systematic prediction of new ferroelectric inorganic materials in point group 6

International Nuclear Information System (INIS)

Abrahams, S.C.

1990-01-01

A total of seven new families and sixteen structurally different inorganic materials with point group 6 are shown to satisfy the criteria presented previously by the present author for predicting ferroelectricity. In case each prediction is experimentally verified, the 183 individual entries for point group 6 listed in the Inorganic Crystal Structure Database will result in over 80 new ferroelectrics, of which about 30 are rare-earth isomorphs. The total number of 'pure'

Mineral commodity profiles: nitrogen

Science.gov (United States)

Kramer, Deborah A.

2004-01-01

Overview -- Nitrogen (N) is an essential element of life and a part of all animal and plant proteins. As a part of the DNA and RNA molecules, nitrogen is an essential constituent of each individual's genetic blueprint. As an essential element in the chlorophyll molecule, nitrogen is vital to a plant's ability to photosynthesize. Some crop plants, such as alfalfa, peas, peanuts, and soybeans, can convert atmospheric nitrogen into a usable form by a process referred to as 'fixation.' Most of the nitrogen that is available for crop production, however, comes from decomposing animal and plant waste or from commercially produced fertilizers. Commercial fertilizers contain nitrogen in the form of ammonium and/or nitrate or in a form that is quickly converted to the ammonium or nitrate form once the fertilizer is applied to the soil. Ammonia is generally the source of nitrogen in fertilizers. Anhydrous ammonia is commercially produced by reacting nitrogen with hydrogen under high temperatures and pressures. The source of nitrogen is the atmosphere, which is almost 80 percent nitrogen. Hydrogen is derived from a variety of raw materials, which include water, and crude oil, coal, and natural gas hydrocarbons. Nitrogen-based fertilizers are produced from ammonia feedstocks through a variety of chemical processes. Small quantities of nitrates are produced from mineral resources principally in Chile. In 2002, anhydrous ammonia and other nitrogen materials were produced in more than 70 countries. Global ammonia production was 108 million metric tons (Mt) of contained nitrogen. With 28 percent of this total, China was the largest producer of ammonia. Asia contributed 46 percent of total world ammonia production, and countries of the former U.S.S.R. represented 13 percent. North America also produced 13 percent of the total; Western Europe, 9 percent; the Middle East, 7 percent; Central America and South America, 5 percent; Eastern Europe, 3 percent; and Africa and Oceania

Springtime variations of organic and inorganic constituents in submicron aerosols (PM1.0) from Cape Hedo, Okinawa

Science.gov (United States)

Kunwar, Bhagawati; Torii, K.; Zhu, Chunmao; Fu, Pingqing; Kawamura, Kimitaka

2016-04-01

During the spring season with enhanced Asian outflow, we collected submicron aerosol (PM1.0) samples at Cape Hedo, Okinawa Island in the western North Pacific Rim. We analyzed the filter samples for diacids, oxoacids, pyruvic acid, α-dicarbonyls and fatty acids to better understand the sources and atmospheric processes in the outflow regions of Asian pollutants. Molecular distributions of diacids show a predominance of oxalic acid (C2) followed by malonic (C3) and succinic (C4) acids. Total diacids strongly correlated with secondary source tracers such as SO42- (r = 0.87), NH4+ (0.90) and methanesulfonate (MSA-) (0.84), suggesting that diacids are secondarily formed from their precursor compounds. We also found good correlations among C2, organic carbon (OC) and elemental carbon (EC) in the Okinawa aerosols, suggesting that diacids are mainly derived from anthropogenic sources. However, a weak correlation of diacids with levoglucosan, a biomass burning tracer, suggests that biomass buring is not the main source of diacids, rather diacids are secondarily formed by photochemical oxidation of organic precursors derived from fossil fuel combustion. We found a strong correlation (r = 0.98) between inorganic nitrogen (NO3-N + NH4-N) and total nitrogen (TN), to which organic nitrogen (ON) contributed 23%. Fatty acids were characterized by even carbon number predominance, suggesting that they are derived from biogenic sources. The higher abundances of short chain fatty acids (C20) further suggest that fatty acids are largely derived from marine phytoplankton during spring bloom.

Effect of organic and inorganic fertilizer applied together on N and P absorption and soil fertility

International Nuclear Information System (INIS)

Wang Kuibo; Yu Meiyan; Shen Xiuzhen; Wang Tongyan; Chen Xueliu; Wang Zhifen

1994-01-01

15 N trace experiments show that organic and inorganic fertilizer applied together promotes organic N mineralization and absorption. Base fertilizer is mainly for nutrition organs and spring fertilizer for reproduction organs. Organic and inorganic fertilizer applied together obtained the highest production efficiency of total N. Total P amount in wheat plant is slightly higher than that of inorganic N applied only, but P distribution in nutrition organs was slightly lower than that of inorganic N applied only. Organic and inorganic fertilizer applied together, not only promoted the production but also increased fertility of soil, so it is an important measure for wheat to obtain high production continuously

Trend of dissolved inorganic nitrogen at stations downstream from the Three-Gorges Dam of Yangtze River

International Nuclear Information System (INIS)

Sun, C.C.; Shen, Z.Y.; Xiong, M.; Ma, F.B.; Li, Y.Y.; Chen, L.; Liu, R.M.

2013-01-01

The TRAMO/SEATS program, combined with the Hodrick–Prescott (HP) filter, was used to detect trends and potential change points in time series of dissolved inorganic nitrogen (DIN) at three stations along the Yangtze River. The trend components were extracted, and two change points were successfully detected. The components revealed that DIN has been increasing at all the stations since the 1990s, although variations exist. Changes visible before 2002 illustrate the differences in agriculture development among regions upstream from the stations. The Three-Gorges Dam (TGD), which began to impound in 2003, led to years of different trends. The DIN concentration, which had been trending upward prior to that date, began a slightly downward trend because of NH 4 + depletion. Readings at the Yichang station revealed this trend most strongly; those at the Hankou station less so. The Datong station was far enough away from the TGD so that no obvious effects were seen. -- Highlights: •TRAMO/SEATS program coupled with HP filter was used to find water quality trends. •Smooth trends other than step trends were separated from trend-cycle components. •DIN concentration was proved to be a reflection of agricultural development. •The three stations experienced different agricultural development since 1990s. •The impoundment of the Three-Gorges Dam can impact as far as to the Hankou station. -- DIN concentrations were reflections of agricultural development in the YRB, but the impoundment of TGD since June, 2003 also had impacts on DIN concentrations far to the Hankou station

Long-term trends of changes in pine and oak foliar nitrogen metabolism in response to chronic nitrogen amendments at Harvard Forest, MA

Science.gov (United States)

Rakesh Minocha; Swathi A. Turlapati; Stephanie Long; William H. McDowell; Subhash C. Minocha

2015-01-01

We evaluated the long-term (1995-2008) trends in foliar and sapwood metabolism, soil solution chemistry and tree mortality rates in response to chronic nitrogen (N) additions to pine and hardwood stands at the Harvard Forest Long Term Ecological Research (LTER) site. Common stress-related metabolites like polyamines (PAs), free amino acids (AAs) and inorganic elements...

Inorganic Fullerene-Like Nanoparticles and Inorganic Nanotubes

Directory of Open Access Journals (Sweden)

Reshef Tenne

2014-11-01

Full Text Available Fullerene-like nanoparticles (inorganic fullerenes; IF and nanotubes of inorganic layered compounds (inorganic nanotubes; INT combine low dimensionality and nanosize, enhancing the performance of corresponding bulk counterparts in their already known applications, as well as opening new fields of their own [1]. This issue gathers articles from the diverse area of materials science and is devoted to fullerene-like nanoparticles and nanotubes of layered sulfides and boron nitride and collects the most current results obtained at the interface between fundamental research and engineering.[...

Organics and nitrogen removal from textile auxiliaries wastewater with A{sup 2}O-MBR in a pilot-scale

Energy Technology Data Exchange (ETDEWEB)

Sun, Faqian [Institute of Environmental Science and Technology, Zhejiang University, Hangzhou 310058 (China); Sun, Bin [Institute of Environmental Science and Technology, Zhejiang University, Hangzhou 310058 (China); Shanghai Electric Group Co. Ltd. Central Academe, Shanghai 200070 (China); Hu, Jian; He, Yangyang [Institute of Environmental Science and Technology, Zhejiang University, Hangzhou 310058 (China); Wu, Weixiang, E-mail: weixiang@zju.edu.cn [Institute of Environmental Science and Technology, Zhejiang University, Hangzhou 310058 (China)

2015-04-09

Highlights: • A pilot-scale A{sup 2}O-MBR system treating textile auxiliaries wastewater was assessed. • Organic matter and recycle ratio strongly affected the performance of the system. • GC/MS analysis found some refractory organics in the MBR permeate. • Combination of organic foulants and inorganic compounds caused membrane fouling. - Abstract: The removal of organic compounds and nitrogen in an anaerobic–anoxic–aerobic membrane bioreactor process (A{sup 2}O-MBR) for treatment of textile auxiliaries (TA) wastewater was investigated. The results show that the average effluent concentrations of chemical oxygen demand (COD), ammonium nitrogen (NH{sub 4}{sup +}–N) and total nitrogen (TN) were about 119, 3 and 48 mg/L under an internal recycle ratio of 1.5. The average removal efficiency of COD, NH{sub 4}{sup +}–N and TN were 87%, 96% and 55%, respectively. Gas chromatograph–mass spectrometer analysis indicated that, although as much as 121 different types of organic compounds were present in the TA wastewater, only 20 kinds of refractory organic compounds were found in the MBR effluent, which could be used as indicators of effluents from this kind of industrial wastewater. Scanning electron microscopy analysis revealed that bacterial foulants were significant contributors to membrane fouling. An examination of foulants components by wavelength dispersive X-ray fluorescence showed that the combination of organic foulants and inorganic compounds enhanced the formation of gel layer and thus caused membrane fouling. The results will provide valuable information for optimizing the design and operation of wastewater treatment system in the textile industry.

Effects of slash removal in an experimental nitrogen gradient. Final report for the project

International Nuclear Information System (INIS)

Nohrstedt, H.Oe.; Ring, Eva; Sikstroem, Ulf; Hoegbom, Lars; Nordlund, Sten

2000-04-01

During four years after clear-felling, the effects of slash removal, including needles, were studied on a productive spruce site (site index G30) in the province of Vaermland, western Sweden. The study was made in an old fertilization experiment, in which at the most 2400 kg N/ha had been added during a twenty-year period. Despite the fact that the site is rich in nitrogen and that much slash was removed (100 ton d. m./ha), there were only very minor effects of the slash removal on the variables under study. These were the composition of soil water, the content of inorganic nitrogen in soil, the biomass of the field layer and the development of the planted spruce seedlings. The only statistically significant effect was that the content of nitrate was reduced in the humus layer. No data supported the idea that the previous fertilization influenced the effect of the slash removal, even though the fertilization had increased the content of total nitrogen in soil and the nitrogen leaching. Thus, we have not been able to repeat the observation from another Swedish study that slash removal reduces leaching of nitrogen and accompanying base cations, e. g. potassium. The effect of slash removal seems to depend on site conditions. Research is needed to reveal the variation in response and decisive factors. Our results, that the survival of spruce seedlings tends to be favoured by slash removal and that the early height growth is unaffected, are in accordance with results from previous studies. Our result, that the biomass of the total field layer is unaffected by slash removal, is not possible to compare with results from other studies, since these were mainly of a qualitative nature

Different land use intensities in grassland ecosystems drive ecology of microbial communities involved in nitrogen turnover in soil.

Science.gov (United States)

Meyer, Annabel; Focks, Andreas; Radl, Viviane; Keil, Daniel; Welzl, Gerhard; Schöning, Ingo; Boch, Steffen; Marhan, Sven; Kandeler, Ellen; Schloter, Michael

2013-01-01

Understanding factors driving the ecology of N cycling microbial communities is of central importance for sustainable land use. In this study we report changes of abundance of denitrifiers, nitrifiers and nitrogen-fixing microorganisms (based on qPCR data for selected functional genes) in response to different land use intensity levels and the consequences for potential turnover rates. We investigated selected grassland sites being comparable with respect to soil type and climatic conditions, which have been continuously treated for many years as intensely used meadows (IM), intensely used mown pastures (IP) and extensively used pastures (EP), respectively. The obtained data were linked to above ground biodiversity pattern as well as water extractable fractions of nitrogen and carbon in soil. Shifts in land use intensity changed plant community composition from systems dominated by s-strategists in extensive managed grasslands to c-strategist dominated communities in intensive managed grasslands. Along the different types of land use intensity, the availability of inorganic nitrogen regulated the abundance of bacterial and archaeal ammonia oxidizers. In contrast, the amount of dissolved organic nitrogen determined the abundance of denitrifiers (nirS and nirK). The high abundance of nifH carrying bacteria at intensive managed sites gave evidence that the amounts of substrates as energy source outcompete the high availability of inorganic nitrogen in these sites. Overall, we revealed that abundance and function of microorganisms involved in key processes of inorganic N cycling (nitrification, denitrification and N fixation) might be independently regulated by different abiotic and biotic factors in response to land use intensity.

Different land use intensities in grassland ecosystems drive ecology of microbial communities involved in nitrogen turnover in soil.

Directory of Open Access Journals (Sweden)

Annabel Meyer

Full Text Available Understanding factors driving the ecology of N cycling microbial communities is of central importance for sustainable land use. In this study we report changes of abundance of denitrifiers, nitrifiers and nitrogen-fixing microorganisms (based on qPCR data for selected functional genes in response to different land use intensity levels and the consequences for potential turnover rates. We investigated selected grassland sites being comparable with respect to soil type and climatic conditions, which have been continuously treated for many years as intensely used meadows (IM, intensely used mown pastures (IP and extensively used pastures (EP, respectively. The obtained data were linked to above ground biodiversity pattern as well as water extractable fractions of nitrogen and carbon in soil. Shifts in land use intensity changed plant community composition from systems dominated by s-strategists in extensive managed grasslands to c-strategist dominated communities in intensive managed grasslands. Along the different types of land use intensity, the availability of inorganic nitrogen regulated the abundance of bacterial and archaeal ammonia oxidizers. In contrast, the amount of dissolved organic nitrogen determined the abundance of denitrifiers (nirS and nirK. The high abundance of nifH carrying bacteria at intensive managed sites gave evidence that the amounts of substrates as energy source outcompete the high availability of inorganic nitrogen in these sites. Overall, we revealed that abundance and function of microorganisms involved in key processes of inorganic N cycling (nitrification, denitrification and N fixation might be independently regulated by different abiotic and biotic factors in response to land use intensity.

Different Land Use Intensities in Grassland Ecosystems Drive Ecology of Microbial Communities Involved in Nitrogen Turnover in Soil

Science.gov (United States)

Meyer, Annabel; Focks, Andreas; Radl, Viviane; Keil, Daniel; Welzl, Gerhard; Schöning, Ingo; Boch, Steffen; Marhan, Sven; Kandeler, Ellen; Schloter, Michael

2013-01-01

Understanding factors driving the ecology of N cycling microbial communities is of central importance for sustainable land use. In this study we report changes of abundance of denitrifiers, nitrifiers and nitrogen-fixing microorganisms (based on qPCR data for selected functional genes) in response to different land use intensity levels and the consequences for potential turnover rates. We investigated selected grassland sites being comparable with respect to soil type and climatic conditions, which have been continuously treated for many years as intensely used meadows (IM), intensely used mown pastures (IP) and extensively used pastures (EP), respectively. The obtained data were linked to above ground biodiversity pattern as well as water extractable fractions of nitrogen and carbon in soil. Shifts in land use intensity changed plant community composition from systems dominated by s-strategists in extensive managed grasslands to c-strategist dominated communities in intensive managed grasslands. Along the different types of land use intensity, the availability of inorganic nitrogen regulated the abundance of bacterial and archaeal ammonia oxidizers. In contrast, the amount of dissolved organic nitrogen determined the abundance of denitrifiers (nirS and nirK). The high abundance of nifH carrying bacteria at intensive managed sites gave evidence that the amounts of substrates as energy source outcompete the high availability of inorganic nitrogen in these sites. Overall, we revealed that abundance and function of microorganisms involved in key processes of inorganic N cycling (nitrification, denitrification and N fixation) might be independently regulated by different abiotic and biotic factors in response to land use intensity. PMID:24039974

Inorganic Nitrogen Leaching from Organic and Conventional Rice Production on a Newly Claimed Calciustoll in Central Asia

DEFF Research Database (Denmark)

Meng, Fanqiao; Olesen, Jørgen E; Sun, Xiangping

2014-01-01

flooded organic and conventional paddies, and inorganic N (NH4-N+NO3-N) was analyzed. Two high-concentration peaks of NH4-N were observed in all treatments: one during early tillering and a second during flowering. A third peak at the mid-tillering stage was observed only under conventional fertilization....... NO3-N concentrations were highest at transplant and then declined until harvest. At the 50 cm soil depth, NO3-N concentration was 21–42% higher than NH4-N in percolation water from organic paddies, while NH4-N and NO3-N concentrations were similar for the conventional and control treatments....... At the depth of 180 cm, NH4-N and NO3-N were the predominant inorganic N for organic and conventional paddies, respectively. Inorganic N concentrations decreased with soil depth, but this attenuation was more marked in organic than in conventional paddies. Conventional paddies leached a higher percentage...

Estimating Inorganic Arsenic Exposure from U.S. Rice and Total Water Intakes

OpenAIRE

Mantha, Madhavi; Yeary, Edward; Trent, John; Creed, Patricia A.; Kubachka, Kevin; Hanley, Traci; Shockey, Nohora; Heitkemper, Douglas; Caruso, Joseph; Xue, Jianping; Rice, Glenn; Wymer, Larry; Creed, John T.

2017-01-01

Background: Among nonoccupationally exposed U.S. residents, drinking water and diet are considered primary exposure pathways for inorganic arsenic (iAs). In drinking water, iAs is the primary form of arsenic (As), while dietary As speciation techniques are used to differentiate iAs from less toxic arsenicals in food matrices. Objectives: Our goal was to estimate the distribution of iAs exposure rates from drinking water intakes and rice consumption in the U.S. population and ethnic- and age-b...

The effects of operating factors on the removal of total ammonia nitrogen and florfenicol antibiotic from synthetic trout fish farm wastewater through nanofiltration

International Nuclear Information System (INIS)

Cheshmberah, F.; Solaimany Nazar, A.R.; Farhadian, M.

2016-01-01

An aquaculture system can be a potentially significant source of antibacterial compounds and ammonia in an aquatic environment. In this study, the removal of total ammonia nitrogen and florfenicol antibiotic from synthetic aqueous wastewater was assessed by applying a commercial thin film composite polyamide nanofilter. The effects of p H (6.5-8.5), pressure (4-10 bar), concentration of total ammonia nitrogen (1-9 mg/L), and florfenicol (0.2-5 mg/L) on the removal efficiency of the nanofilter were studied at a constant 70% recovery rate. It was found that by increasing the p H within the range of 6.5 to 8.5, it enhanced the removal efficiency by up to 98% and 100% for total ammonia nitrogen and florfenicol, respectively. With an increase in pressure from 4 to 7 bar, the removal percentage increased and then, it decreased from 7 to 10 bar. The interactions factors did not have significant effects on the both pollutants removal efficiencies. To obtain optimal removal efficiencies, an experimental design and statistical analysis via the response surface method were adopted.

Strongly coupled inorganic/nanocarbon hybrid materials for advanced electrocatalysis.

Science.gov (United States)

Liang, Yongye; Li, Yanguang; Wang, Hailiang; Dai, Hongjie

2013-02-13

Electrochemical systems, such as fuel cell and water splitting devices, represent some of the most efficient and environmentally friendly technologies for energy conversion and storage. Electrocatalysts play key roles in the chemical processes but often limit the performance of the entire systems due to insufficient activity, lifetime, or high cost. It has been a long-standing challenge to develop efficient and durable electrocatalysts at low cost. In this Perspective, we present our recent efforts in developing strongly coupled inorganic/nanocarbon hybrid materials to improve the electrocatalytic activities and stability of inorganic metal oxides, hydroxides, sulfides, and metal-nitrogen complexes. The hybrid materials are synthesized by direct nucleation, growth, and anchoring of inorganic nanomaterials on the functional groups of oxidized nanocarbon substrates including graphene and carbon nanotubes. This approach affords strong chemical attachment and electrical coupling between the electrocatalytic nanoparticles and nanocarbon, leading to nonprecious metal-based electrocatalysts with improved activity and durability for the oxygen reduction reaction for fuel cells and chlor-alkali catalysis, oxygen evolution reaction, and hydrogen evolution reaction. X-ray absorption near-edge structure and scanning transmission electron microscopy are employed to characterize the hybrids materials and reveal the coupling effects between inorganic nanomaterials and nanocarbon substrates. Z-contrast imaging and electron energy loss spectroscopy at single atom level are performed to investigate the nature of catalytic sites on ultrathin graphene sheets. Nanocarbon-based hybrid materials may present new opportunities for the development of electrocatalysts meeting the requirements of activity, durability, and cost for large-scale electrochemical applications.

Biogeochemical generation of dissolved inorganic carbon and nitrogen in the North Branch of inner Changjiang Estuary in a dry season

Science.gov (United States)

Zhai, Wei-Dong; Yan, Xiu-Li; Qi, Di

2017-10-01

We investigated the surface water carbonate system, nutrients, and relevant hydrochemical parameters in the inner Changjiang (Yangtze River) Estuary in early spring 2009 and 2010. The two surveys were carried out shortly after spring-tide days, and covered both the channel-like South Branch and the freshwater-blocked North Branch. In the North Branch, with a water residence time of approximately one month, we detected remarkable partial pressures of CO2 (pCO2) of 930-1518 μatm with a salinity range of 4.5-17.4, which were substantially higher than the South Branch pCO2 values of 700-1100 μatm at salinities of less than 0.88. The North Branch pCO2 distribution pattern is unique compared with many other estuaries where aquatic pCO2 normally declines with salinity increase. Furthermore, the biogeochemical additions of ammonium (7.4-65.7 μmol kg-1) and alkalinity (196-695 μmol kg-1) were identified in salinities between 4 and 16 in the North Branch. Based on field data analyses and simplified stoichiometric equations, we suggest that the relatively high North Branch pCO2 values and estuarine additions of dissolved inorganic nitrogen/carbon in the mid-salinity area were strongly associated with each other. These signals were primarily controlled by biogeochemical processes in the North Branch, combining biogenic organic matter decomposition (i.e. respiration), ammonia oxidation, CaCO3 dissolution, and CO2 degassing. In the upper reach of the South Branch, notable salinity values of 0.20-0.88 were detected, indicating saltwater spillover from the North Branch. These spillover waters had minor contributions (1.5-6.9%) to the springtime nutrient, dissolved inorganic carbon, and alkalinity export fluxes from Changjiang to the adjacent East China Sea. This is the first attempt to understand the biogeochemical controls of the unique pCO2 distributions in the North Branch, and to evaluate the effects of saltwater spillover from the North Branch on dry-season export fluxes

Effect of nitrogen dressings on growth and development of sugar-beet

NARCIS (Netherlands)

Houba, V.J.G.

1973-01-01

The growth and development of sugar-beet with different nitrogen dressings was studied by measurement of leaf area and of dry weight and chemical composition (inorganic cations and anions) of several plant parts during the growth season.

For a correct interpretation of the data, the losses in

Nitrogen metabolism of the eutrophic Delaware River ecosystem

International Nuclear Information System (INIS)

Anon.

1986-01-01

A comprehensive investigation of the nitrogen cycle in the Delaware River was carried out using 13 N tracers to measure rates for important transformations of nitrogen. Daily, depth-averaged 15 N rates for the principal inorganic nitrogen species were consistent with rates derived from longitudinal profiles of concentration in the river. The data indicated that nitrification was a rapid, irreversible sink for NH 4 + , with export of the product NO 3 - from the study area. Utilization of NO 3 - by primary producers was negligible, owing to low irradiance levels and to high NH 4 + concentrations. The oxygen sag near Philadelphia was found to result from oxygen demand in the water column, with only minor benthic influence. Reaeration provided the major oxygen input. Nitrification accounted for about 1% of the net oxygen demand near Philadelphia but as much as 25% farther downstream

Sensitivity of nitrogen dioxide concentrations to oxides of nitrogen controls in the United Kingdom

International Nuclear Information System (INIS)

Dixon, J.

2001-01-01

There is a possibility of further controls on emissions to the atmosphere of nitrogen dioxides to meet air quality objectives in the UK. Data in the National Air Quality Archive were used to calculate the likely sensitivity of hourly concentrations of nitrogen dioxide in ambient urban air to changes in the total oxides of nitrogen. Since the role of atmospheric chemical reactions is to make the responses non-linearly dependent on the emissions control, we seek to establish the magnitude and sign of the effects that this non-linearity might cause. We develop a quantitative approach to analysing the non-linearity in the data. Polynomial fits have been developed for the empirical ratio NO 2 :NO x (the 'yield'). They describe nitrogen dioxide concentrations using total oxides of nitrogen. The new functions have the important feature of increased yield in winter episodes. Simpler functions tend to omit this feature of the yields at the highest hourly concentrations. Based on this study, the hourly nitrogen dioxide objective in the UK may require emissions control of no more than about 50% on total oxides of nitrogen at the most polluted sites: other sites require less or even no control. (Author)

Fate of recovery boiler smelt nitrogen in the recovery cycle; Soodakattilan sulan typpiyhdisteitten kaeyttaeytyminen talteenottoprosessissa

Energy Technology Data Exchange (ETDEWEB)

Hupa, M.; Forssen, M.; Backman, R.; Ek, P.; Hulden, S.G.; Kilpinen, P.; Kymaelaeinen, M.; Malm, H. [Aabo Akademi, Turku (Finland). Combustion Chemistry Research Group

1997-10-01

The purpose of this project is to study the fate of the nitrogen bound in the inorganic smelt after it enters the dissolving tank. Of special interest is to find in what form this nitrogen can be found further down in the recovery process and especially in what form it can be removed from the process. The aim is to clarify if the nitrogen can be a potential problem in the process or if it can become a potential emission. The work is divided into choosing methods for the analysis of different nitrogen species, collection and analysis of mill samples, laboratory studies and theoretical studies on nitrogen chemistry in alkaline solutions and reporting

Non-ammonium reduced nitrogen species in atmospheric aerosol particles

Energy Technology Data Exchange (ETDEWEB)

Dod, R.L.; Gundel, L.A.; Benner, W.H.; Novakov, T.

1983-08-01

The traditional belief that ambient aerosol particles contain nitrogen predominantly in the form of inorganic ionic species such as NH/sub 4//sup +/ and NO/sub 3//sup -/ was challenged about 10 years ago by results from x-ray photoelectron spectroscopic analysis (ESCA) of California aerosol particles. A significant fraction (approx. 50%) of the reduced nitrogen was observed to have an oxidation state more reduced than ammonium, characteristic of organic nitrogen species. We have used a recently developed thermal evolved gas analysis method (NO/sub x/) in conjunction with ESCA to confirm the existence of these species in aerosol particles collected in both the United States and Europe. The agreement of EGA and ESCA analyses indicates that these species are found not only on the surface but also throughout the particles. 9 references, 6 figures.

Identifying organic nitrogen compounds in Rocky Mountain National Park aerosols

Science.gov (United States)

Beem, K. B.; Desyaterik, Y.; Ozel, M. Z.; Hamilton, J. F.; Collett, J. L.

2010-12-01

Nitrogen deposition is an important issue in Rocky Mountain National Park (RMNP). While inorganic nitrogen contributions to the ecosystems in this area have been studied, the sources of organic nitrogen are still largely unknown. To better understand the potential sources of organic nitrogen, filter samples were collected and analyzed for organic nitrogen species. Samples were collected in RMNP using a Thermo Fisher Scientific TSP (total suspended particulate) high-volume sampler with a PM2.5 impactor plate from April - November of 2008. The samples presented the opportunity to compare two different methods for identification of individual organic nitrogen species. The first type of analysis was performed with a comprehensive two dimensional gas chromatography (GCxGC) system using a nitrogen chemiluminescence detector (NCD). The filter samples were spiked with propanil in dichloromethane to use as an internal standard and were then extracted in water followed by solid phase extraction. The GCxGC system was comprised of a volatility based separation (DB5 column) followed by a polarity based separation (RXI-17 column). A NCD was used to specifically detect nitrogen compounds and remove the complex background matrix. Individual standards were used to identify peaks by comparing retention times. This method has the added benefit of an equimolar response for nitrogen so only a single calibration is needed for all species. In the second analysis, a portion of the same filter samples were extracted in DI water and analyzed with liquid chromatography coupled with mass spectroscopy (LC/MS). The separation was performed using a C18 column and a water-methanol gradient elution. Electrospray ionization into a time of flight mass spectrometer was used for detection. High accuracy mass measurement allowed unambiguous assignments of elemental composition of resulting ions. Positive and negative polarities were used since amines tend to show up in positive mode and nitrates in

A SWAT model validation of nested-scale contemporaneous stream flow, suspended sediment and nutrients from a multiple-land-use watershed of the central USA.

Science.gov (United States)

Zeiger, Sean J; Hubbart, Jason A

2016-12-01

There is an ongoing need to validate the accuracy of predictive model simulated pollutant yields, particularly from multiple-land-use (i.e. forested, agricultural, and urban) watersheds. However, there are seldom sufficient observed data sets available that supply requisite spatial and temporal resolution and coupled multi-parameter constituents for rigorous model performance assessment. Four years of hydroclimate and water quality data were used to validate SWAT model estimates of monthly stream flow, suspended sediment, total phosphorus, nitrate, nitrite, ammonium, and total inorganic nitrogen from 5 nested-scale gauging sites located in a multiple-land-use watershed of the central USA. The uncalibrated SWAT model satisfactorily simulated monthly stream flow with Nash-Sutcliffe efficiency (NSE) values ranging from 0.50 near the headwaters, to 0.75 near the watershed outlet. However, the uncalibrated model did not accurately simulate monthly sediment, total phosphorus, nitrate, nitrite, ammonium, and total inorganic nitrogen with NSE valuesSWAT model to multiple gauging sites within the watershed improved estimates of monthly stream flow (NSE=0.83), sediment (NSE=0.78), total phosphorus (NSE=0.81), nitrate (NSE=0.90), and total inorganic nitrogen (NSE=0.86). However, NSE values were model performance decreased for sediment, nitrate, and total inorganic nitrogen during the validation period with NSE valuesSWAT model to multiple gauging sites and provide guidance to SWAT model (or similar models) users wishing to improve model performance at multiple scales. Copyright © 2016 Elsevier B.V. All rights reserved.

GENETIC VARIABILITY OF SUGARCANE-ASSOCIATED DIAZOTROPHIC BACTERIA CAPABLE OF INORGANIC PHOSPHATE SOLUBILIZING

OpenAIRE

Lira-Cadete, Luana; Barbosa de Farias, Andreza Raquel; de Souza Ramos, Andresa Priscila; da Costa, Diogo Paes; Freire, Fernando Jose; Kuklinsky-Sobral, Julia

2013-01-01

The sugarcane is a culture of great importance for the Brazilian agriculture. Every year this culture consumes great amounts of nitrogen and phosphate fertilizers. However, the use of plant growth-promoting bacteria can reduce the use of the chemical fertilizers, contributing to the economy and the environment conservation. So, the goal of this study was to select sugarcane-associated diazotrophic bacteria able to solubilize inorganic phosphate and to evaluate the genetic diversity of these b...

Effect of long-term combined application of organic and inorganic fertilizers on soil nematode communities within aggregates.

Science.gov (United States)

Zhang, Zhiyong; Zhang, Xiaoke; Mahamood, Md; Zhang, Shuiqing; Huang, Shaomin; Liang, Wenju

2016-08-09

A long-term fertilization experiment was conducted to examine the effects of different fertilization practices on nematode community composition within aggregates in a wheat-maize rotation system. The study was a randomized complete block design with three replicates. The experiment involved the following four treatments: no fertilizer, inorganic N, P and K fertilizer (NPK), NPK plus manure (NPKM) and NPK plus maize straw (NPKS). Soil samples were taken at 0-20 cm depth during the wheat harvest stage. Based on our results, NPKS contributed to soil aggregation and moisture retention, with a positive effect on soil total nitrogen accumulation, particularly within small macroaggregates (0.25-1 mm) and microaggregates (fertilizer application effectively improved soil physicochemical properties and were also beneficial for nematode survival within small aggregate size fractions.

Coulometric precise analysis of total inorganic carbon in seawater and measurements of radiocarbon for the carbon dioxide in the atmosphere and for the total inorganic carbon in seawater

International Nuclear Information System (INIS)

Ishii, Masao; Inoue, Hisayuki Y.; Matsueda Hidekazu

2000-01-01

Climate change is one of the biggest issues on the earth, and the research on the climate system has been paid much attention today. The behavior of carbon dioxide (Co 2 ), one of the major green house gases, and its related substances within and among the atmosphere, the ocean and the land biosphere is playing a key role in regulating the climate. The ocean contains ca. 4x10 19 g of carbon, which is about 50 times of that in the atmosphere. The change in carbon cycle in the ocean is considered to have a crucial impact on the concentration of CO 2 in the atmosphere. However, little has been quantitatively known about the variability of CO 2 in the ocean and its controlling physical, chemical and biological processes. The observations of the concentration and carbon isotopic ratio of total dissolved inorganic carbon (TCO 2 ) in seawater occupy important part of the research on the behavior of carbon in the ocean. In the first part of this report, we describe the fundamental knowledge of CO 2 system in seawater and the method to precisely measure TCO 2 including sampling method, the structure and the operation of the instrument we developed, and the way to assure the quality of the data. We also present some results we obtained in the western North Pacific and the equatorial Pacific. In the second part, we report the methods to collect and treat samples for the analysis of the isotopic ratio of radio carbon ( 14 C) in the atmospheric CO 2 and TCO 2 in sea water. (author)

Responses of ecosystem nitrogen cycle to nitrogen addition: a meta-analysis.

Science.gov (United States)

Lu, Meng; Yang, Yuanhe; Luo, Yiqi; Fang, Changming; Zhou, Xuhui; Chen, Jiakuan; Yang, Xin; Li, Bo

2011-03-01

• Anthropogenic nitrogen (N) addition may substantially alter the terrestrial N cycle. However, a comprehensive understanding of how the ecosystem N cycle responds to external N input remains elusive. • Here, we evaluated the central tendencies of the responses of 15 variables associated with the ecosystem N cycle to N addition, using data extracted from 206 peer-reviewed papers. • Our results showed that the largest changes in the ecosystem N cycle caused by N addition were increases in soil inorganic N leaching (461%), soil NO₃⁻ concentration (429%), nitrification (154%), nitrous oxide emission (134%), and denitrification (84%). N addition also substantially increased soil NH₄+ concentration (47%), and the N content in belowground (53%) and aboveground (44%) plant pools, leaves (24%), litter (24%) and dissolved organic N (21%). Total N content in the organic horizon (6.1%) and mineral soil (6.2%) slightly increased in response to N addition. However, N addition induced a decrease in microbial biomass N by 5.8%. • The increases in N effluxes caused by N addition were much greater than those in plant and soil pools except soil NO₃⁻, suggesting a leaky terrestrial N system. © 2010 The Authors. New Phytologist © 2010 New Phytologist Trust.

Determination of total inorganic arsenic in potable water through spectroscopy of atomic absorption with generation of hydride

International Nuclear Information System (INIS)

Rodriguez Roman, Susan; Barquero, M.

2000-01-01

Arsenic is an element that has been studied in the analysis of environmental samples for its toxicity showed in very low concentrations. The objective of this work is the validation of a method for the determination of total inorganic arsenic in drinking water. Through the spectrophotometric technique of atomic absorption an automatic system of flow injection for the generation of hydrides is used. The prereduction of Arsenic was made with potasium iodide 1,5% m/v and ascorbic acid 0.25% m/v dissolved in hydrochloric acid 3,7% m/v. The recuperation percentage of the method was 97 ± 3% in a dynamic range to 30 μg/L. The detection limit was 0,7 μg/L established over 0,5 mL of sample. The samples analyzed were found under the set limits of normative in Costa Rica of 10 μg/L. (author) [es

New features on the environmental regulation of metabolism revealed by modeling the cellular proteomic adaptations induced by light, carbon and inorganic nitrogen in Chlamydomonas reinhardtii

Directory of Open Access Journals (Sweden)

Stéphanie Gérin

2016-08-01

Full Text Available Microalgae are currently emerging to be very promising organisms for the production of biofuels and high-added value compounds. Understanding the influence of environmental alterations on their metabolism is a crucial issue. Light, carbon and nitrogen availability have been reported to induce important metabolic adaptations. So far, the influence of these variables has essentially been studied while varying only one or two environmental factors at the same time. The goal of the present work was to model the cellular proteomic adaptations of the green microalga Chlamydomonas reinhardtii upon the simultaneous changes of light intensity, carbon concentrations (CO2 and acetate and inorganic nitrogen concentrations (nitrate and ammonium in the culture medium. Statistical design of experiments (DOE enabled to define 32 culture conditions to be tested experimentally. Relative protein abundance was quantified by two dimensional differential in-gel electrophoresis (2D-DIGE. Additional assays for respiration, photosynthesis, and lipid and pigment concentrations were also carried out. A hierarchical clustering survey enabled to partition biological variables (proteins + assays into eight co-regulated clusters. In most cases, the biological variables partitioned in the same cluster had already been reported to participate to common biological functions (acetate assimilation, bioenergetic processes, light harvesting, Calvin cycle and protein metabolism. The environmental regulation within each cluster was further characterized by a series of multivariate methods including principal component analysis and multiple linear regressions. This metadata analysis enabled to highlight the existence of a clear regulatory pattern for every cluster and to mathematically simulate the effects of light, carbon and nitrogen. The influence of these environmental variables on cellular metabolism is described in details and thoroughly discussed. This work provides an overview

Integrated Nitrogen and Flow Modelling (INCA) in a Boreal River Basin Dominated by Forestry: Scenarios of Environmental Change

International Nuclear Information System (INIS)

Rankinen, Katri; Lepistoe, Ahti; Granlund, Kirsti

2004-01-01

A new version (v1.7) of the Integrated Nitrogen in CAtchments model(INCA) was applied to the northern boreal Simojoki river basin (3160 km 2 ) in Finland. The INCA model is a semi-distributed, dynamic nitrogen (N) process model which simulates N transport and processes in catchments. The INCA model was applied to model flow and seasonal inorganic N dynamics of the river Simojoki basin over the period 1994-1996, and validated for two more years. Both calibration and validation of the model were successful. The model was able to simulate annual dynamics of inorganic N concentrations in the river. The effects of forest management and atmospheric deposition on inorganic N fluxes to the sea in 2010 were studied. Three scenarios were applied for forestry practices and two for deposition. The effects of forest cutting scenarios and atmospheric deposition scenarios on inorganic N flux to the sea were small. The combination of the maximum technically possible reduction of N deposition and a decrease of 100% in forest cutting and peat mining areas decreased NO 3 - -N flux by 6.0% and NH 4 + -N flux by 3.1%

Use of Potato Nitrogen Concentrate in the Production of α-Amylase by Aspergillus oryzae

Directory of Open Access Journals (Sweden)

Eric Thaller

2007-01-01

Full Text Available The influence of various nitrogen sources and media supplements on α-amylase (EC 3.2.1.1 formation by Aspergillus oryzae ATCC 1011 was investigated in shake flask experiments and batch fermentations. Both inorganic and organic nitrogen-containing supplements have been applied, while corn starch and ammonium sulphate were used as the major source of carbon and nitrogen, respectively. Shake flask experiments revealed that potato nitrogen concentrate (PNC is almost equivalent to corn steep liquor (CSL in supporting amylase formation. A pretreatment step consisting of clarification of the turbid material did not show any significant effect. The replacement of the inorganic nitrogen source by sodium nitrate led to lower enzyme yields. Other complex supplements may reduce the enzyme level formed, e.g. casein hydrolysate, or increase the amylase titre slightly, e.g. yeast extract or malt extract. Cultivations in instrumented bench top reactors on media supplemented with PNC led to higher cell growth rates and yields of α-amylase in comparison with the medium without any supplement. Replacement of PNC by CSL revealed a slightly increased enzyme level, which is in the range of 9–17 % after 100 h of cultivation. Only minor differences were revealed in the growth kinetics and enzyme formation when PNC was used as the sole nitrogen source, replacing a mixture of soybean meal, yeast extract, malt extract and casein hydrolysate in bioreactor cultivations with lactose as the carbon source. However, metabolic differences as seen from the course of dissolved oxygen tension (DOT, α-amino nitrogen concentration and the amount of acid needed to maintain a constant pH were observed.

Linking agricultural crop management and air quality models for regional to national-scale nitrogen assessments

Science.gov (United States)

Cooter, E. J.; Bash, J. O.; Benson, V.; Ran, L.

2012-10-01

While nitrogen (N) is an essential element for life, human population growth and demands for energy, transportation and food can lead to excess nitrogen in the environment. A modeling framework is described and implemented to promote a more integrated, process-based and system-level approach to the estimation of ammonia (NH3) emissions which result from the application of inorganic nitrogen fertilizers to agricultural soils in the United States. The United States Department of Agriculture (USDA) Environmental Policy Integrated Climate (EPIC) model is used to simulate plant demand-driven fertilizer applications to commercial cropland throughout the continental US. This information is coupled with a process-based air quality model to produce continental-scale NH3 emission estimates. Regional cropland NH3 emissions are driven by the timing and amount of inorganic NH3 fertilizer applied, soil processes, local meteorology, and ambient air concentrations. Initial fertilizer application often occurs when crops are planted. A state-level evaluation of EPIC-simulated, cumulative planted area compares well with similar USDA reported estimates. EPIC-annual, inorganic fertilizer application amounts also agree well with reported spatial patterns produced by others, but domain-wide the EPIC values are biased about 6% low. Preliminary application of the integrated fertilizer application and air quality modeling system produces a modified geospatial pattern of seasonal NH3 emissions that improves current simulations of observed atmospheric particle nitrate concentrations. This modeling framework provides a more dynamic, flexible, and spatially and temporally resolved estimate of NH3 emissions than previous factor-based NH3 inventories, and will facilitate evaluation of alternative nitrogen and air quality policy and adaptation strategies associated with future climate and land use changes.

Synthesis of a composite inorganic membrane for the separation of nitrogen, tetrafluoromethane and hexafluoropropylene

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Hertzog Bissett

2011-09-01

Full Text Available Composite inorganic membranes were synthesised for gas component separation of N2, CF4 and C3F6. Selectivities lower than Knudsen selectivities were obtained due to membrane defects. A composite ceramic membrane consisting of a ceramic support structure, a MFI intermediate zeolite layer and a Teflon top layer, was developed to improve separation.

Letter to the editor: Critical assessments of the current state of scientific knowledge, terminology, and research needs concerning the ecological effects of elevated atmospheric nitrogen deposition in China

Science.gov (United States)

Pan, Yuepeng; Liu, Yongwen; Wentworth, Gregory R.; Zhang, Lin; Zhao, Yuanhong; Li, Yi; Liu, Xuejun; Du, Enzai; Fang, Yunting; Xiao, Hongwei; Ma, Hongyuan; Wang, Yuesi

2017-03-01

In a publication in Atmospheric Environment (http://dx.doi.org/10.1016/j.atmosenv.2015.10.081), Gu et al. (2015) estimated that "the total nitrogen (N) deposition in 2010 was 2.32 g N m-2 yr-1" in China. This value is comparable with previous estimations based on a synthesized dataset of wet/bulk inorganic N deposition observations, which underestimates the total N deposition since their algorithm (equations (2) and (3) in their paper) does not account for dry deposition of NH3, HNO3, NOx and wet/dry deposition of HONO and organic nitrogen (e.g. amines, amides, PAN). Indeed, Gu et al. (2015) mixed the terminology of wet/bulk deposition and total deposition. Another flawed assumption by Gu et al. (2015) is that all inorganic N in precipitation estimated by their algorithm originates from fertilizer and coal combustion. This is incorrect and almost certainly causes biases in the spatial and temporal distribution of estimated wet/bulk inorganic N deposition (Fig. 5 in their paper), further considering the fact that they neglected important N sources like livestock and they did not consider the nonlinearity between various sources and deposition. Besides the input data on N deposition, the model validation (Sect. 2.3.2) described in their paper also requires clarification because the detailed validation information about the time series of observational dataset versus modeling results was not given. As a result of these combined uncertainties in their estimation of N deposition and the lack of detail for model-measurement comparison, their estimates of the impacts of N deposition on carbon storage in Chinese forests may need further improvement. We suggest the clarification of the terminology regarding N deposition, especially for wet deposition, bulk deposition, gaseous and particulate dry deposition or total deposition since the accurate distinction between these terms is crucial to investigating and estimating the effects of N deposition on ecosystems.

Recent changes in anthropogenic reactive nitrogen compounds

Science.gov (United States)

Andronache, Constantin

2014-05-01

Significant anthropogenic perturbations of the nitrogen cycle are the result of rapid population growth, with mounting need for food and energy production. The increase of reactive nitrogen compounds (such as NOx, HNO3, NH3, and N2O) has a significant impact on human health, environment, and climate. NOx emissions contribute to O3 chemistry, aerosol formation and acidic precipitation. Ammonia is a notable atmospheric pollutant that may deteriorate ecosystems and contribute to respiratory problems. It reacts with acidic gases to form aerosols or is deposited back to ecosystems. The application of fertilizers accounts for most of the N2O production, adding to greenhouse gas emissions. We analyze the change of some reactive nitrogen compounds based on observations, in eastern United States. Results show that the control of NOx and SO2 emissions over the last decades caused a significant decrease of acidic deposition. The nitrate deposition is highest in eastern US, while the ammonium ion concentration is highest in central US regions. Overall, the inorganic nitrogen wet deposition from nitrate and ammonium is enhanced in central, and eastern US. Research shows that sensitive ecosystems in northeastern regions exhibit a slow recovery from the accumulated effects of acidic deposition. Given the growing demand for nitrogen in agriculture and industry, we discuss possible pathways to reduce the impact of excess reactive nitrogen on the environment.

Impact of organic and inorganic fertilizers application on the phytochemical and antioxidant activity of Kacip Fatimah (Labisia pumila Benth).

Science.gov (United States)

Ibrahim, Mohd Hafiz; Jaafar, Hawa Z E; Karimi, Ehsan; Ghasemzadeh, Ali

2013-09-05

A study was conducted to compare secondary metabolites and antioxidant activity of Labisia pumila Benth (Kacip Fatimah) in response to two sources of fertilizer [i.e., organic (chicken dung; 10% N:10% P₂O₅:10% K₂O) and inorganic fertilizer (NPK green; 15% N, 15% P₂O₅, 15% K₂O)] under different N rates of 0, 90, 180 and 270 kg N/ha. The experiment was arranged in a randomized complete block design replicated three times. At the end of 15 weeks, it was observed that the application of organic fertilizer enhanced the production of total phenolics, flavonoids, ascorbic acid, saponin and gluthathione content in L. pumila, compared to the use of inorganic fertilizer. The nitrate content was also reduced under organic fertilization. The application of nitrogen at 90 kg N/ha improved the production of secondary metabolites in Labisia pumila. Higher rates in excess of 90 kg N/ha reduced the level of secondary metabolites and antioxidant activity of this herb. The DPPH and FRAP activity was also highest at 90 kg N/ha. The results indicated that the use of chicken dung can enhance the production of secondary metabolites and improve antioxidant activity of this herb.

The effects of operating factors on the removal of total ammonia nitrogen and florfenicol antibiotic from synthetic trout fish farm wastewater through nanofiltration

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Ali Reza Solaimany Nazar

2016-04-01

Full Text Available An aquaculture system can be a potentially significant source of antibacterial compounds and ammonia in an aquatic environment. In this study, the removal of total ammonia nitrogen and florfenicol antibiotic from synthetic aqueous wastewater was assessed by applying a commercial TFC (thin film composite polyamide nanofilter. The effects of pH (6.5-8.5, pressure (4-10 bar, concentration of total ammonia nitrogen (1-9 mg/L, and florfenicol (0.2-5 mg/L on the removal efficiency of the nanofilter were studied at a constant 70% recovery rate. It was found that by increasing the pH within the range of 6.5 to 8.5, it enhanced the removal efficiency by up to 98% and 100% for total ammonia nitrogen and florfenicol, respectively. With an increase in pressure from 4 to 7 bar, the removal percentage increased and then, it decreased from 7 to 10 bar. The interactions factors did not have significant effects on the both pollutants removal efficiencies. To obtain optimal removal efficiencies, an experimental design and statistical analysis via the response surface method were adopted.

Growth response of four freshwater algal species to dissolved organic nitrogen of different concentration and complexity

DEFF Research Database (Denmark)

Fiedler, Dorothea; Graeber, Daniel; Badrian, Maria

2015-01-01

1. Dissolved organic nitrogen (DON) compounds dominate the nitrogen pool of many lakes, but their importance as nitrogen sources for freshwater phytoplankton is not fully understood. Previous growth experiments demonstrated the availability of urea and amino acids but often at unnaturally high...... (DCAA), natural organic matter (NOM)) or with nitrate as the sole nitrogen source. Monocultures of Chlamydomonas spp., Cyclotella meneghiniana, Microcystis aeruginosa and Anabaena flos-aquae were incubated with dissolved nitrogen compounds at concentrations ranging from 0.01 to 0.5 mg N L−1, which...... and their compound preferences. Therefore, DON composition can influence biomass and structure of phytoplankton communities. 6. These experiments demonstrate the importance of the main DON compounds for phytoplankton growth when no inorganic nitrogen is available. DON should in future be included in nitrogen budget...

Characterization of the compounds of nitrogen and total suspended particles in the municipality Regla, Havana

International Nuclear Information System (INIS)

Wallo Vazquez, Antonio; Cuesta Santos, Osvaldo

2006-01-01

The questions related with the atmospheric contamination in urban areas every day they charge bigger importance for the affectations that it can take place so much in the health of the human beings as in the materials, constructions, etc. In the city of Havana those made up of nitrogen and the particles suspended totals are of the pollutants whose concentrations are elevated in the atmosphere. Inside this context, the present work intends the analysis of the behavior of this concentrations, taken as experimental polygon the municipality Regla in city of Havana

Nitrogen cycling in a turbid, tidal estuary - de stikstofkringloop in een troebel getijden estuarium

NARCIS (Netherlands)

Andersson, M.G.I.

2007-01-01

In this thesis I investigated nitrification, dissolved inorganic and organic nitrogen uptake, and the relative importance of nitrification and ammonium assimilation. I have also investigated exchange with marshes and sediments. Nitrification, oxidation of ammonium to nitrate is the first step for

Noble gas separation with the use of inorganic adsorbents

International Nuclear Information System (INIS)

Pence, D.T.; Chou, C.C.; Christian, J.D.; Paplawsky, W.J.

1979-01-01

A noble gas separation process is proposed for application to airborne nuclear fuel reprocessing plant effluents. The process involves the use of inorganic adsorbents for the removal of contaminant gases and noble gas separation through selective adsorption. Water and carbon dioxide are removed with selected zeolites that do not appreciably adsorb the noble gases. Xenon is essentially quantitatively removed with a specially developed adsorbent using conventional adsorption-desorption techniques. Oxygen is removed to low ppM levels by the use of a rapid cycle adsorption technique on a special adsorbent leaving a krypton-nitrogen mixture. Krypton is separated from nitrogen with a special adsorbent operated at about -80 0 C. Because the separation process does not require high pressures and oxygen is readily removed to sufficiently limit ozone formation to insignificant levels, appreciable capital and operating cost savings with this process are possible compared with other proposed processes. In addition, the proposed process is safer to operate

Calcium constrains plant control over forest ecosystem nitrogen cycling.

Science.gov (United States)

Groffman, Peter M; Fisk, Melany C

2011-11-01

Forest ecosystem nitrogen (N) cycling is a critical controller of the ability of forests to prevent the movement of reactive N to receiving waters and the atmosphere and to sequester elevated levels of atmospheric carbon dioxide (CO2). Here we show that calcium (Ca) constrains the ability of northern hardwood forest trees to control the availability and loss of nitrogen. We evaluated soil N-cycling response to Ca additions in the presence and absence of plants and observed that when plants were present, Ca additions "tightened" the ecosystem N cycle, with decreases in inorganic N levels, potential net N mineralization rates, microbial biomass N content, and denitrification potential. In the absence of plants, Ca additions induced marked increases in nitrification (the key process controlling ecosystem N losses) and inorganic N levels. The observed "tightening" of the N cycle when Ca was added in the presence of plants suggests that the capacity of forests to absorb elevated levels of atmospheric N and CO2 is fundamentally constrained by base cations, which have been depleted in many areas of the globe by acid rain and forest harvesting.

Concentration, flux, and the analysis of trends of total and dissolved phosphorus, total nitrogen, and chloride in 18 tributaries to Lake Champlain, Vermont and New York, 1990–2011

Science.gov (United States)

Medalie, Laura

2013-01-01

Annual concentration, flux, and yield for total phosphorus, dissolved phosphorus, total nitrogen, and chloride for 18 tributaries to Lake Champlain were estimated for 1990 through 2011 using a weighted regression method based on time, tributary streamflows (discharges), and seasonal factors. The weighted regression method generated two series of daily estimates of flux and concentration during the period of record: one based on observed discharges and a second based on a flow-normalization procedure that removes random variation due to year-to-year climate-driven effects. The flownormalized estimate for a given date is similar to an average estimate of concentration or flux that would be made if all of the observed discharges for that date were equally likely to have occurred. The flux bias statistic showed that 68 of the 72 flux regression models were minimally biased. Temporal trends in the concentrations and fluxes were determined by calculating percent changes in flow-normalized annual fluxes for the full period of analysis (1990 through 2010) and for the decades 1990–2000 and 2000–2010. Basinwide, flow-normalized total phosphorus flux decreased by 42 metric tons per year (t/yr) between 1990 and 2010. This net result reflects a basinwide decrease in flux of 21 metric tons (t) between 1990 and 2000, followed by a decrease of 20 t between 2000 and 2010; both results were largely influenced by flux patterns in the large tributaries on the eastern side of the basin. A comparison of results for total phosphorus for the two separate decades of analysis found that more tributaries had decreasing concentrations and flux rates in the second decade than the first. An overall reduction in dissolved phosphorus flux of 0.7 t/yr was seen in the Lake Champlain Basin during the full period of analysis. That very small net change in flux reflects substantial reductions between 1990 and 2000 from eastern tributaries, especially in Otter Creek and the LaPlatte and Winooski

Welcome to Inorganics: A New Open Access, Inclusive Forum for Inorganic Chemistry

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Duncan H. Gregory

2013-06-01

Full Text Available One of the beauties of inorganic chemistry is its sheer diversity. Just as chemistry sits at the centre of the sciences, inorganic chemistry sits at the centre of chemistry itself. Inorganic chemists are fortunate in having the entire periodic table at their disposal, providing a palette for the creation of a multitude of rich and diverse compounds and materials from the simplest salts to the most complex of molecular species. It follows that the language of inorganic chemistry can thus be a demanding one, accommodating sub-disciplines with very different perspectives and frames of reference. One could argue that it is the unequivocal breadth of inorganic chemistry that empowers inorganic chemists to work at the interfaces, not just between the traditional Inorganic-Organic-Physical boundaries of the discipline, but in the regions where chemistry borders the other physical and life sciences, engineering and socio-economics. [...

Chitin: 'Forgotten' Source of Nitrogen: From Modern Chitin to Thermally Mature Kerogen: Lessons from Nitrogen Isotope Ratios

Science.gov (United States)

Schimmelmann, A.; Wintsch, R.P.; Lewan, M.D.; DeNiro, M.J.

1998-01-01

Chitinous biomass represents a major pool of organic nitrogen in living biota and is likely to have contributed some of the fossil organic nitrogen in kerogen. We review the nitrogen isotope biogeochemistry of chitin and present preliminary results suggesting interaction between kerogen and ammonium during thermal maturation. Modern arthropod chitin may shift its nitrogen isotope ratio by a few per mil depending on the chemical method of chitin preparation, mostly because N-containing non-amino-sugar components in chemically complex chitin cannot be removed quantitatively. Acid hydrolysis of chemically complex chitin and subsequent ion-chromatographic purification of the "deacetylated chitin-monomer" D-glucosamine (in hydrochloride form) provides a chemically well-defined, pure amino-sugar substrate for reproducible, high-precision determination of ??15N values in chitin. ??15N values of chitin exhibited a variability of about one per mil within an individual's exoskeleton. The nitrogen isotope ratio differed between old and new exoskeletons by up to 4 per mil. A strong dietary influence on the ??15N value of chitin is indicated by the observation of increasing ??15N values of chitin from marine crustaceans with increasing trophic level. Partial biodegradation of exoskeletons does not significantly influence ??15N values of remaining, chemically preserved amino sugar in chitin. Diagenesis and increasing thermal maturity of sedimentary organic matter, including chitin-derived nitrogen-rich moieties, result in humic compounds much different from chitin and may significantly change bulk ??15N values. Hydrous pyrolysis of immature source rocks at 330??C in contact with 15N-enriched NH4Cl, under conditions of artificial oil generation, demonstrates the abiogenic incorporation of inorganic nitrogen into carbon-bound nitrogen in kerogen. Not all organic nitrogen in natural, thermally mature kerogen is therefore necessarily derived from original organic matter, but may

Effects of nitrogen and carbon sources on the production of inulinase from strain Bacillus sp. SG113

Science.gov (United States)

Gavrailov, Simeon; Ivanova, Viara

2016-03-01

The effects of the carbon and nitrogen substrates on the growth of Bacillus sp. SG113 strain were studied. The use of organic nitrogen sources (peptone, beef extract, yeast extract, casein) leads to rapid cellular growth and the best results for the Bacillus strain were obtained with casein hydrolysate. From the inorganic nitrogen sources studied, the (NH4) 2SO4 proved to be the best nitrogen source. Casein hydrolysate and (NH4) 2SO4 stimulated the invertase synthesis. In the presence of Jerusalem artichoke, onion and garlic extracts as carbon sources the strain synthesized from 6 to 10 times more inulinase.

Competition between autotrophic and heterotrophic microbial plankton for inorganic nutrients induced by variability in estuarine biophysicochemical conditions

Science.gov (United States)

Williams, A.; Quigg, A.

2016-02-01

Competition for inorganic nutrients between autotrophic and heterotrophic fractions of microbial plankton (0.2-20μm) was investigated at two stations in a sub-tropical estuary, Galveston Bay, Texas. Competition potential between these groups is enhanced because individuals are similar in size, reducing variability among their nutrient uptake efficiencies. Further, in estuaries, allochthonous supplements to autochthonous carbon may satisfy heterotrophic requirements, allowing alternative factors to limit abundance. The relative abundance of autotrophs and heterotrophs stained with SYBR Green I and enumerated on a Beckman Coulter Gallios flow cytometer were evaluated monthly during a year-long study. Shifts in the relative in situ abundance were significantly related to temperature, dissolved inorganic nitrogen (DIN), phosphorous (Pi), and total organic carbon (TOC) concentrations revealing opposing gradients of limitation by different abiotic factors. In corresponding in vitro nutrient enrichment bioassays the relative contribution of autotrophic or heterotrophic microbial plankton to significant enrichment responses varied. Only during macro- (>20μm) phytoplankton blooms do autotrophic microbial plankton respond to nutrient enrichment. Contrastingly, the heterotrophic microbial plankton responded to nutrient enrichment primarily when temperature limitation was alleviated. Therefore, the potential for autotrophic and heterotrophic microbial plankton competition for limiting nutrients is highest when autotrophic microbial plankton are also competing with larger phytoplankton during bloom events. Based on this evidence, we hypothesize that the autotrophic microbial fraction has a competitive advantage over the heterotrophs for inorganic nutrients in Galveston Bay. The observed microbial competition during estuarine phytoplankton blooms may have important consequences on biogeochemical processes including carbon and nutrient cycling.

Nitrogen uptake and regeneration pathways in the equatorial Pacific: a basin scale modeling study

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R. Le Borgne

2009-11-01

Full Text Available It is well known that most primary production is fueled by regenerated nitrogen in the open ocean. Therefore, studying the nitrogen cycle by focusing on uptake and regeneration pathways would advance our understanding of nitrogen dynamics in the marine ecosystem. Here, we carry out a basin-scale modeling study, by assessing model simulations of nitrate and ammonium, and rates of nitrate uptake, ammonium uptake and regeneration in the equatorial Pacific. Model-data comparisons show that the model is able to reproduce many observed features of nitrate, ammonium, such as the deep ammonium maximum (DAM. The model also reproduces the observed de-coupling of ammonium uptake and regeneration, i.e., regeneration rate greater than uptake rate in the lower euphotic zone. The de-coupling largely explains the observed DAM in the equatorial Pacific Ocean. Our study indicates that zooplankton excretion and remineralization of organic nitrogen play a different role in nitrogen regeneration. Rates of zooplankton excretion vary from <0.01 mmol m⁻³ d⁻¹ to 0.1 mmol m⁻³ d⁻¹ in the upper euphotic zone while rates of remineralization fall within a narrow range (0.015–0.025 mmol m⁻³ d⁻¹ . Zooplankton excretion contributes up to 70% of total ammonium regeneration in the euphotic zone, and is largely responsible for the spatial variability of nitrogen regeneration. However, remineralization provides a steady supply of ammonium in the upper ocean, and is a major source of inorganic nitrogen for the oligotrophic regions. Overall, ammonium generation and removal are approximately balanced over the top 150 m in the equatorial Pacific.

A case study of the relative effects of power plant nitrogen oxides and sulfur dioxide emission reductions on atmospheric nitrogen deposition.

Science.gov (United States)

Vijayaraghavan, Krish; Seigneur, Christian; Bronson, Rochelle; Chen, Shu-Yun; Karamchandani, Prakash; Walters, Justin T; Jansen, John J; Brandmeyer, Jo Ellen; Knipping, Eladio M

2010-03-01

The contrasting effects of point source nitrogen oxides (NOx) and sulfur dioxide (SO2) air emission reductions on regional atmospheric nitrogen deposition are analyzed for the case study of a coal-fired power plant in the southeastern United States. The effect of potential emission reductions at the plant on nitrogen deposition to Escambia Bay and its watershed on the Florida-Alabama border is simulated using the three-dimensional Eulerian Community Multiscale Air Quality (CMAQ) model. A method to quantify the relative and individual effects of NOx versus SO2 controls on nitrogen deposition using air quality modeling results obtained from the simultaneous application of NOx and SO2 emission controls is presented and discussed using the results from CMAQ simulations conducted with NOx-only and SO2-only emission reductions; the method applies only to cases in which ambient inorganic nitrate is present mostly in the gas phase; that is, in the form of gaseous nitric acid (HNO3). In such instances, the individual effects of NOx and SO2 controls on nitrogen deposition can be approximated by the effects of combined NOx + SO2 controls on the deposition of NOy, (the sum of oxidized nitrogen species) and reduced nitrogen species (NHx), respectively. The benefit of controls at the plant in terms of the decrease in nitrogen deposition to Escambia Bay and watershed is less than 6% of the overall benefit due to regional Clean Air Interstate Rule (CAIR) controls.

Effects of polyacrylamide on soil erosion and nutrient losses from substrate material in steep rocky slope stabilization projects.

Science.gov (United States)

Chen, Zhang; Chen, Wenlu; Li, Chengjun; Pu, Yanpin; Sun, Haifeng

2016-06-01

Erosion of denuded steep rocky slopes causes increasing losses of nitrogen and phosphorus, which is a severe problem in rocky slope protection. Thus, it is important to determine the appropriate materials that can reduce the erodibility and losses of nitrogen and phosphorus of the soil. In this paper, twenty-seven simulated rainfall events were carried out in a greenhouse, in which the substrate material was artificial soil; nine types of anionic polyacrylamide (PAM) were studied, which consisted of three molecular weight (6, 12, and 18 Mg mol(-1)) and three charge density (10, 20, and 30%) formulations in a 3 by 3 factorial design. The results showed that: (1) Polyacrylamide application reduced total nitrogen losses by 35.3% to 50.0% and total phosphorus losses by 34.9% to 48.0% relative to the control group. (2) The losses of total nitrogen and total phosphorus had significant correlation with the molecular weight. Besides, the losses of total phosphorus, particulate-bound phosphorus and inorganic nitrogen (NH4-N) were significantly correlated with their molecular weight and charge density. However, the losses of dissolved organic nitrogen, inorganic nitrogen (NO3-N), dissolved organic phosphorus, inorganic phosphorus (PO4-P) were non-significantly correlated with molecular weight and charge density. (3) Particulate-bound nitrogen and phosphorus were responsible for the losses of nitrogen and phosphorus during runoff events, where particulate-bound nitrogen made up 71.7% to 73.2% of total nitrogen losses, and particulate-bound phosphorus made up 82.3% to 85.2% of total phosphorus losses. (4) Polyacrylamide treatments increased water-stable aggregates content by 32.3% to 59.1%, total porosity by 11.3% to 49.0%, final infiltrative rate by 41.3% to 72.5%, and reduced soil erosion by 18.9% to 39.8% compared with the control group. Overall, the results of this study indicated that polyacrylamide application in the steep rocky slope stabilization projects could

Nectar sugars and amino acids in day- and night-flowering Nicotiana species are more strongly shaped by pollinators' preferences than organic acids and inorganic ions.

Science.gov (United States)

Tiedge, Kira; Lohaus, Gertrud

2017-01-01

Floral nectar contains mainly sugars but also amino acids, organic acids, inorganic ions and secondary compounds to attract pollinators. The genus Nicotiana exhibits great diversity among species in floral morphology, flowering time, nectar compositions, and predominant pollinators. We studied nectar samples of 20 Nicotiana species, composed equally of day- and night-flowering plants and attracting different groups of pollinators (e.g. hummingbirds, moths or bats) to investigate whether sugars, amino acids, organic acids and inorganic ions are influenced by pollinator preferences. Glucose, fructose and sucrose were the only sugars found in the nectar of all examined species. Sugar concentration of the nectar of day-flowering species was 20% higher and amino acid concentration was 2-3-fold higher compared to the nectar of night-flowering species. The sucrose-to-hexose ratio was significantly higher in night-flowering species and the relative share of sucrose based on the total sugar correlated with the flower tube length in the nocturnal species. Flowers of different tobacco species contained varying volumes of nectar which led to about 150-fold higher amounts of total sugar per flower in bat- or sunbird-pollinated species than in bee-pollinated or autogamous species. This difference was even higher for total amino acids per flower (up to 1000-fold). As a consequence, some Nicotiana species invest large amounts of organic nitrogen for certain pollinators. Higher concentrations of inorganic ions, predominantly anions, were found in nectar of night-flowering species. Therefore, higher anion concentrations were also associated with pollinator types active at night. Malate, the main organic acid, was present in all nectar samples but the concentration was not correlated with pollinator type. In conclusion, statistical analyses revealed that pollinator types have a stronger effect on nectar composition than phylogenetic relations. In this context, nectar sugars and amino

Nectar sugars and amino acids in day- and night-flowering Nicotiana species are more strongly shaped by pollinators’ preferences than organic acids and inorganic ions

Science.gov (United States)

Tiedge, Kira; Lohaus, Gertrud

2017-01-01

Floral nectar contains mainly sugars but also amino acids, organic acids, inorganic ions and secondary compounds to attract pollinators. The genus Nicotiana exhibits great diversity among species in floral morphology, flowering time, nectar compositions, and predominant pollinators. We studied nectar samples of 20 Nicotiana species, composed equally of day- and night-flowering plants and attracting different groups of pollinators (e.g. hummingbirds, moths or bats) to investigate whether sugars, amino acids, organic acids and inorganic ions are influenced by pollinator preferences. Glucose, fructose and sucrose were the only sugars found in the nectar of all examined species. Sugar concentration of the nectar of day-flowering species was 20% higher and amino acid concentration was 2-3-fold higher compared to the nectar of night-flowering species. The sucrose-to-hexose ratio was significantly higher in night-flowering species and the relative share of sucrose based on the total sugar correlated with the flower tube length in the nocturnal species. Flowers of different tobacco species contained varying volumes of nectar which led to about 150-fold higher amounts of total sugar per flower in bat- or sunbird-pollinated species than in bee-pollinated or autogamous species. This difference was even higher for total amino acids per flower (up to 1000-fold). As a consequence, some Nicotiana species invest large amounts of organic nitrogen for certain pollinators. Higher concentrations of inorganic ions, predominantly anions, were found in nectar of night-flowering species. Therefore, higher anion concentrations were also associated with pollinator types active at night. Malate, the main organic acid, was present in all nectar samples but the concentration was not correlated with pollinator type. In conclusion, statistical analyses revealed that pollinator types have a stronger effect on nectar composition than phylogenetic relations. In this context, nectar sugars and amino

Nectar sugars and amino acids in day- and night-flowering Nicotiana species are more strongly shaped by pollinators' preferences than organic acids and inorganic ions.

Directory of Open Access Journals (Sweden)

Kira Tiedge

Full Text Available Floral nectar contains mainly sugars but also amino acids, organic acids, inorganic ions and secondary compounds to attract pollinators. The genus Nicotiana exhibits great diversity among species in floral morphology, flowering time, nectar compositions, and predominant pollinators. We studied nectar samples of 20 Nicotiana species, composed equally of day- and night-flowering plants and attracting different groups of pollinators (e.g. hummingbirds, moths or bats to investigate whether sugars, amino acids, organic acids and inorganic ions are influenced by pollinator preferences. Glucose, fructose and sucrose were the only sugars found in the nectar of all examined species. Sugar concentration of the nectar of day-flowering species was 20% higher and amino acid concentration was 2-3-fold higher compared to the nectar of night-flowering species. The sucrose-to-hexose ratio was significantly higher in night-flowering species and the relative share of sucrose based on the total sugar correlated with the flower tube length in the nocturnal species. Flowers of different tobacco species contained varying volumes of nectar which led to about 150-fold higher amounts of total sugar per flower in bat- or sunbird-pollinated species than in bee-pollinated or autogamous species. This difference was even higher for total amino acids per flower (up to 1000-fold. As a consequence, some Nicotiana species invest large amounts of organic nitrogen for certain pollinators. Higher concentrations of inorganic ions, predominantly anions, were found in nectar of night-flowering species. Therefore, higher anion concentrations were also associated with pollinator types active at night. Malate, the main organic acid, was present in all nectar samples but the concentration was not correlated with pollinator type. In conclusion, statistical analyses revealed that pollinator types have a stronger effect on nectar composition than phylogenetic relations. In this context

Fluxes of oxidised and reduced nitrogen above a mixed coniferous forest exposed to various nitrogen emission sources

International Nuclear Information System (INIS)

Neirynck, J.; Kowalski, A.S.; Carrara, A.; Genouw, G.; Berghmans, P.; Ceulemans, R.

2007-01-01

Concentrations of nitrogen gases (NH 3 , NO 2 , NO, HONO and HNO 3 ) and particles (pNH 4 and pNO 3 ) were measured over a mixed coniferous forest impacted by high nitrogen loads. Nitrogen dioxide (NO 2 ) represented the main nitrogen form, followed by nitric oxide (NO) and ammonia (NH 3 ). A combination of gradient method (NH 3 and NO x ) and resistance modelling techniques (HNO 3 , HONO, pNH 4 and pNO 3 ) was used to calculate dry deposition of nitrogen compounds. Net flux of NH 3 amounted to -64 ng N m -2 s -1 over the measuring period. Net fluxes of NO x were upward (8.5 ng N m -2 s -1 ) with highest emission in the morning. Fluxes of other gases or aerosols substantially contributed to dry deposition. Total nitrogen deposition was estimated at -48 kg N ha -1 yr -1 and consisted for almost 80% of NH x . Comparison of throughfall nitrogen with total deposition suggested substantial uptake of reduced N (±15 kg N ha -1 yr -1 ) within the canopy. - Reduced nitrogen was found to be the main contributor to total deposition which was predominantly governed by dry deposition

Exogenous trehalose improves growth under limiting nitrogen through upregulation of nitrogen metabolism.

Science.gov (United States)

Lin, Yingchao; Zhang, Jie; Gao, Weichang; Chen, Yi; Li, Hongxun; Lawlor, David W; Paul, Matthew J; Pan, Wenjie

2017-12-19

The trehalose (Tre) pathway has strong effects on growth and development in plants through regulation of carbon metabolism. Altering either Tre or trehalose 6-phosphate (T6P) can improve growth and productivity of plants as observed under different water availability. As yet, there are no reports of the effects of modification of Tre orT6P on plant performance under limiting nutrition. Here we report that nitrogen (N) metabolism is positively affected by exogenous application of Tre in nitrogen-deficient growing conditions. Spraying foliage of tobacco (Nicotiana tabacum) with trehalose partially alleviated symptoms of nitrogen deficiency through upregulation of nitrate and ammonia assimilation and increasing activities of nitrate reductase (NR), glycolate oxidase (GO), glutamine synthetase (GS) and glutamine oxoglutarate aminotransferase (GOGAT) with concomitant changes in ammonium (NH 4 + ) and nitrate (NO 3 - ) concentrations, glutamine and amino acids. Chlorophyll and total nitrogen content of leaves and rates of photosynthesis were increased compared to nitrogen-deficient plants without applied Tre. Total plant biomass accumulation was also higher in Tre -fed nitrogen-deficient plants, with a smaller proportion of dry weight partitioned to roots, compared to nitrogen-deficient plants without applied Tre. Consistent with higher nitrogen assimilation and growth, Tre application reduced foliar starch. Minimal effects of Tre feeding were observed on nitrogen-sufficient plants. The data show, for the first time, significant stimulatory effects of exogenous Tre on nitrogen metabolism and growth in plants growing under deficient nitrogen. Under such adverse conditions metabolism is regulated for survival rather than productivity. Application of Tre can alter this regulation towards maintenance of productive functions under low nitrogen. This has implications for considering approaches to modifying the Tre pathway for to improve crop nitrogen-use efficiency and

Organic nitrogen and carbon in atmospheric dry and wet depositions in the southern East China Sea: its implication for new production in coastal region

Science.gov (United States)

Chen, H. Y.; Yeh, J. X.; Lin, C. T.

2016-02-01

We collected 11 sets of size-segregated particulate aerosol (include coarse and fine particles) and 53 rain samples from January to December 2014 at a coastal city (Keelung) on the southern East China Sea. Here we present measurements of water-soluble inorganic/organic nitrogen and carbon (WSIN/WSON and WSIC/WSOC, respectively) in aerosol samples and dissolved inorganic/organic nitrogen and carbon (DIN/DON and DIC/DOC, respectively) in rain samples. In addition, 4-d back trajectories of air masses arriving daily at the sampling site were calculated to determine the potential aerosol source regions. The concentrations of water-soluble species in particulate aerosols were relatively high in March (WSON: 223±48 nmol m-3; WSOC: 203±51 nmol m-3) and dissolved species in rain samples were high in December (DON: 157±69 μM; DOC: 294±168 μM), which occur frequently during the spring and winter. The monsoon system of East Asia play a key role on the atmospheric composition of nitrogen and carbon, with higher loadings in northerly (winter to spring) than southerly (summer to autumn) monsoon periods, owing to strong emissions from the East Asian continent. Our results indicate that biomass burning and dust events yielded the largest concentrations of ON and OC not only on particulate aerosols but also in precipitations. For aerosols, the amounts of WSON and WSOC accounted for 42±8% and 80±7% of the water-soluble total nitrogen (WSTN) and carbon (WSTC), respectively. Additionally, the concentrations of DON and DOC accounted for 40±5% and 75±3% of total dissolved nitrogen (TDN) and carbon (TDC), respectively, for precipitations. By using dry and wet deposition flux estimations, we estimated that the fluxes of WSTN/TDN and WSTC/TDC were 47.1±24.4 / 266±20 mmol m-2 yr-1 and 23±9 / 153±3 mmol m-2 yr-1, respectively. These results suggest that atmospheric deposition contributed approximately 25-34% of the annual biological new production in the southern East China Sea.

Is the characterisation of the total nitrogen in industrial waste water always correct? Study of a case; Es siempre correcta la caracterizacion del nitrogeno total en las aguas residuales industriales?. Estudio de un caso

Energy Technology Data Exchange (ETDEWEB)

Torrijos, M.; Carrera, J.; Lafuente, J. [Universitat Autonoma de Barcelona (Spain)

2003-07-01

This paper intends to advise about the possibility of wrong industrial wastewater characterisations related to the Total Kjeldahl Nitrogen (TKN), in order to avoid inaccurate design and management of the system. During the study of the high strength nitrogen removal process in a pharmaceutical wastewater treatment plant, an abnormality was observed in the nitrogen mass balance of the system. The most popular method for TKN determination was modified in order to assess properly the TKN of the effluent. This modification has demonstrated that there are some organic nitrified compounds with complex structure that cannot be completely chemically hydrolysed. This could be the reason for wrong characterisations in industrial wastewaters with similar compounds. (Author) 6 refs.

Effect of different nitrogen application types on nitrogen utilization efficiency and fate of fertilizer for sugacane

International Nuclear Information System (INIS)

Wei Jianfeng; Wei Dongping; Liu Huanyu; Chen Chaojun; Lan Libin; Liang He

2013-01-01

A pot experiment in greenhouse was conducted with "1"5N-labeled urea 5 g/pot (equal to 450 kg · hm"-"2) total nitrogen by three kinds of treatments of disposable bottom application nitrogen before sowing (T1), 50% nitrogen before sowing and 50% nitrogrn during tillering stage (T2), and 30% nitrogen before sowing, 30% nitrogen during tillering stage and 40% nitrogen applied during elongation stage (T3) to investigate the use efficiency and fate of fertilizer nitrogen using the sugarcane cultivar ROC22. Results showed that almost 18% ∼ 29% of total N uptake by sugarcane was supplied by fertilizer, and 71% ∼ 82% N derived from soil and seed-stem. Nitrogen use efficiency ranged from 21.0% to 34.52%, with "1"5N-fertilizer residue of 37.61% ∼ 44.13%, and "1"5N-fertilizer loss of 21.35% ∼ 41.39% among three treatments. Under the three levels of nitrogen application, residual was "1"5N-fertilizer was mainly distributed in 0 ∼ 20 cm top soil. The uptake of nitrogen and the proportion of total N from fertilizer in sugarcane plant, the yield of stalk and sugar after the nitrogen applied, and the use efficiency and residue ratio of "1"5N-fertilizer increased significantly over time, while loss rate of "1"5N-fertilizer decreased significantly with a slight decline trend of nitrogen distribution and sucrose accumulation in stalk. The results also indicated that after the nitrogen applied the amounts "1"5N-fertilizer residue in 0 ∼ 20 cm top soil showed a rising trend, but dropped in 20 ∼ 40 cm soil profile. From the viewpoints of economic benefit and ecological benefit, the nitrogen fertilizer applied of T3 could be optimal treatment. (authors)

NITROGEN LOSS FROM SMALL WATERSHEDS IN THE OREGON CASCADES: A STUDY OF FOREST SUCCESSION INFLUENCE

Science.gov (United States)

Traditional biogeochemical theory suggests that biotic N limitation (N demand by plants and soil microorganisms) controls ecosystem nitrogen (N) losses, and that stream N export should increase with successional age. I am examining patterns of inorganic and organic N export from...

Plant biomass, soil microbial community structure and nitrogen cycling under different organic amendment regimes; a

NARCIS (Netherlands)

Heijboer, Amber; Berge, ten Hein F.M.; Ruiter, de Peter C.; Jørgensen, Helene Bracht; Kowalchuk, George A.; Bloem, Jaap

2016-01-01

Sustainable agriculture requires nutrient management options that lead to a profitable crop yield with relatively low nitrogen (N) losses to the environment. We studied whether the addition of contrasting organic amendments together with inorganic fertilizer can promote both requirements

Effect of nitrogen sources on some morphological characteristics of in vitro stevia rebaudiana Bertoni.

Science.gov (United States)

Akbari, F; Arminian, A; Kahrizi, D; Fazeli, A

2017-02-28

Stevia rebaudiana Bertoni belongs to Asteraceae family that leaves 200-300 times sweeter than sugar. Low seed fertility is one of the most important problems in Stevia production. So, Plant tissue culture is an efficient method for mass propagation of Stevia. In this research, we studied the effect of various concentrations of nitrogen on some morphological traits of stevia under in vitro conditions. We used axillary nodes as explants and they were cultured on Murashige and Skoog (MS) medium containing inorganic nitrogen sources i.e. NH4NO3(0, 825 and 1650 mg/l), KNO3(0, 950 and 1900 mg/l) were observed. The cultures were kept for 4 weeks at a temperature of 25±2°C with a photoperiod of 16/8 hour low light/dark each day. Maximum shoot length (89.33 mm), dry weight of plants (0.10 mg) and leaf fresh weight (0.42 mg) was observed on MS medium with 1650 mg/l NH4NO3 and 950 mg/l KNO3. Minimum shoot length (6.13 mm), root length (6.60 mm), leaf number (4.26), leaf dry weight (0.01 mg), leaf fresh weight (0.05 mg), total dry and fresh weight (0.02 and 0.15 mg) and growth rate was observed on a MS medium without nitrogen sources. Moreover, presence of nitrogen sources increases both shooting and rooting in Stevia rebaudiana Bertoni.

On-line technique for preparingand measuring stable carbon isotopeof total dissolved inorganic carbonin water samples ( d13CTDIC

Directory of Open Access Journals (Sweden)

S. Inguaggiato

2005-06-01

Full Text Available A fast and completely automated procedure is proposed for the preparation and determination of d13C of total inorganic carbon dissolved in water ( d13CTDIC. This method is based on the acidification of water samples transforming the whole dissolved inorganic carbon species into CO2. Water samples are directly injected by syringe into 5.9 ml vials with screw caps which have a pierciable rubber septum. An Analytical Precision «Carbonate Prep System» was used both to flush pure helium into the vials and to automatically dispense a fixed amount of H3PO4. Full-equilibrium conditions between produced CO2 and water are reached at a temperature of 70°C (± 0.1°C in less than 24 h. Carbon isotope ratios (13C/ 12C were measured on an AP 2003 continuous flow mass spectrometer, connected on-line with the injection system. The precision and reproducibility of the proposed method was tested both on aqueous standard solutions prepared using Na2CO3 with d13C=-10.78 per mil versus PDB (1 s= 0.08, n = 11, and at five different concentrations (2, 3, 4, 5 and 20 mmol/l and on more than thirty natural samples. Mean d13CTDIC on standard solution samples is ?10.89 < per mil versus PDB (1 s= 0.18, n = 50, thus revealing both a good analytical precision and reproducibility. A comparison between average d13CTDIC values on a quadruplicate set of natural samples and those obtained following the chemical and physical stripping method highlights a good agreement between the two analytical methods.

Looking beyond fertilizer: Assessing the contribution of nitrogen from hydrologic inputs and organic matter to plant growth in the cranberry agroecosystem

Science.gov (United States)

Stackpoole, S.M.; Kosola, K.R.; Workmaster, B.A.A.; Guldan, N.M.; Browne, B.A.; Jackson, R. D.

2011-01-01

Even though nitrogen (N) is a key nutrient for successful cranberry production, N cycling in cranberry agroecosystems is not completely understood. Prior research has focused mainly on timing and uptake of ammonium fertilizer, but the objective of our study was to evaluate the potential for additional N contributions from hydrologic inputs (flooding, irrigation, groundwater, and precipitation) and organic matter (OM). Plant biomass, soil, surface and groundwater samples were collected from five cranberry beds (cranberry production fields) on four different farms, representing both upland and lowland systems. Estimated average annual plant uptake (63.3 ?? 22.5 kg N ha-1 year-1) exceeded total average annual fertilizer inputs (39.5 ?? 11.6 kg N ha-1 year-1). Irrigation, precipitation, and floodwater N summed to an average 23 ?? 0.7 kg N ha-1 year-1, which was about 60% of fertilizer N. Leaf and stem litterfall added 5.2 ?? 1.2 and 24.1 ?? 3.0 kg N ha-1 year-1 respectively. The estimated net N mineralization rate from the buried bag technique was 5 ?? 0.2 kg N ha-1 year-1, which was nearly 15% of fertilizer N. Dissolved organic nitrogen represented a significant portion of the total N pool in both surface water and soil samples. Mixed-ion exchange resin core incubations indicated that 80% of total inorganic N from fertilizer, irrigation, precipitation, and mineralization was nitrate, and approximately 70% of recovered inorganic N from groundwater was nitrate. There was a weak but significant negative relationship between extractable soil ammonium concentrations and ericoid mycorrhizal colonization (ERM) rates (r = -0.22, P fertilizer N in order to maximize the benefits of ERM fungi in actively mediating N cycling in cranberry agroecosystems. ?? 2011 Springer Science+Business Media B.V.

Determinação das formas de nitrogênio e nitrogênio total em rochas-reservatório de petróleo por destilação com arraste de vapor e método do indofenol Determination of nitrogen forms and total nitrogen in petroleum reservoir rocks by steam distillation and the indophenol method

Directory of Open Access Journals (Sweden)

Lílian Irene Dias da Silva

2006-02-01

Full Text Available Several extraction procedures are described for the determination of exchangeable and fixed ammonium, nitrate + nitrite, total exchangeable nitrogen and total nitrogen in certified reference soils and petroleum reservoir rock samples by steam distillation and indophenol method. After improvement of the original distillation system, an increase in worker safety, a reduction in time consumption, a decrease of 73% in blank value and an analysis without ammonia loss, which could possibly occur, were achieved. The precision (RSD < 8%, n = 3 and the detection limit (9 mg kg-1 NH4+-N are better than those of published procedures.

Interactive effects of ocean acidification and nitrogen limitation on two bloom-forming dinoflagellate species

NARCIS (Netherlands)

Eberlein, T.; Van de Waal, D.B.; Brandenburg, Karen M.; John, U.; Voss, M.; Achterberg, E.P.; Rost, B.

2016-01-01

Global climate change involves an increase in oceanic CO2 concentrations as well as thermal stratification of the water column, thereby reducing nutrient supply from deep to surface waters. Changes in inorganic carbon (C) or nitrogen (N) availability have been shown to affect marine primary

Atmospheric outflow of nutrients to the Bay of Bengal: Impact of anthropogenic sources..

Digital Repository Service at National Institute of Oceanography (India)

Srinivas, B.; Sarin, M.M.; Sarma, V.V.S.S.

outflow show pronounced temporal variability. The inorganic nitrogen (NH4 + -N: ~90% of NInorg) dominates the total soluble nitrogen (NTot). Although the contribution of organic nitrogen is not significant, the mass ratio of NOrg/NTotin the outflow varied...

Characterization and source identification of nitrogen in a riverine system of monsoon-climate region, China.

Science.gov (United States)

Yuan, Jie; Li, Siyue; Han, Xi; Chen, Qiuyang; Cheng, Xiaoli; Zhang, Quanfa

2017-08-15

There are increasing concerns in nitrogen (N) pollution worldwide, especially in aquatic ecosystems, and thus quantifying its sources in waterways is critical for pollution prevention and control. In this study, we investigated the spatio-temporal variabilities of inorganic N concentration (i.e., NO 3 - , NH 4 + ) and total dissolved N (TDN) and identified their sources in waters and suspended matters using an isotopical approach in the Jinshui River, a river with a length of 87km in the monsoon-climate region of China. The spatio-temporal inorganic N concentrations differed significantly along the longitudinal gradient in the river network. The NO 3 - , NH 4 + and TDN concentrations ranged from 0.02 to 1.12mgl -1 , 0.03 to 4.28mgl -1 , and 0.33 to 2.78mgl -1 , respectively. The 15 N tracing studies demonstrated that N in suspended organic matter was in the form of suspended particulate nitrogen (SPN) and was primarily from atmospheric deposition and agricultural fertilizer. In contrast, N in stream waters was mainly in the form of nitrate and was from atmospheric deposition, fertilizers, soil, and sewage. Meanwhile, both δ 15 N-SPN and δ 15 N-NO 3 - peaked in the rainy season (i.e., July) because of higher terrigenous sources via rain runoff, demonstrating the dominant diffusive N sources in the catchment. Thus, our results could provide critical information on N pollution control and sustainable watershed management of the riverine ecosystem in monsoon-climate region. Copyright © 2017 Elsevier B.V. All rights reserved.

Investigation of laser-induced breakdown spectroscopy and multivariate analysis for differentiating inorganic and organic C in a variety of soils

International Nuclear Information System (INIS)

Martin, Madhavi Z.; Mayes, Melanie A.; Heal, Katherine R.; Brice, Deanne J.; Wullschleger, Stan D.

2013-01-01

Laser-induced breakdown spectroscopy (LIBS) along with multivariate analysis was used to differentiate between the total carbon (C), inorganic C, and organic C in a set of 58 different soils from 5 soil orders. A 532 nm laser with 45 mJ of laser power was used to excite the 58 samples of soil and the emission of all the elements present in the soil samples was recorded in a single spectrum with a wide wavelength range of 200–800 nm. The results were compared to the laboratory standard technique, e.g., combustion on a LECO-CN analyzer, to determine the true values for total C, inorganic C, and organic C concentrations. Our objectives were: 1) to determine the characteristic spectra of soils containing different amounts of organic and inorganic C, and 2) to examine the viability of this technique for differentiating between soils that contain predominantly organic and/or inorganic C content for a range of diverse soils. Previous work has shown that LIBS is an accurate and reliable approach to measuring total carbon content of soils, but it remains uncertain whether inorganic and organic forms of carbon can be separated using this approach. Total C and inorganic C exhibited correlation with rock-forming elements such as Al, Si, Fe, Ti, Ca, and Sr, while organic C exhibited minor correlation with these elements and a major correlation with Mg. We calculated a figure of merit (Mg/Ca) based on our results to enable differentiation between inorganic versus organic C. We obtained the LIBS validation prediction for total, inorganic, and organic C to have a coefficient of regression, r 2 = 0.91, 0.87, and 0.91 respectively. These examples demonstrate an advance in LIBS-based techniques to distinguish between organic and inorganic C using the full wavelength spectra. - Highlights: • This research has successfully identified the organic and inorganic carbon in soil. • Multivariate analysis was used to show success in building a statistical model. • Can be used to

Use of stable nitrogen isotope 15N in investigating nitrogen uptake by plants from allylisothiocyanate decomposition products

International Nuclear Information System (INIS)

Dolejskova, J.; Kovar, J.

1976-01-01

The assimilability of nitrogen from allylisothiocyanate or from its nitrogenous decomposition products by plants was investigated using 15 N-labelled allylisothiocyanate. The results show that plant nitrogen assimilation from allylisothiocyanate is the higher, the lower the total nitrogen content of the nutritive medium. (author)

Combined nitrogen limitation and cadmium stress stimulate total carbohydrates, lipids, protein and amino acid accumulation in Chlorella vulgaris (Trebouxiophyceae).

Science.gov (United States)

Chia, Mathias Ahii; Lombardi, Ana Teresa; da Graça Gama Melão, Maria; Parrish, Christopher C

2015-03-01

Metals have interactive effects on the uptake and metabolism of nutrients in microalgae. However, the effect of trace metal toxicity on amino acid composition of Chlorella vulgaris as a function of varying nitrogen concentrations is not known. In this research, C. vulgaris was used to investigate the influence of cadmium (10(-7) and 2.0×10(-8)molL(-1) Cd) under varying nitrogen (2.9×10(-6), 1.1×10(-5) and 1.1×10(-3)molL(-1)N) concentrations on its growth rate, biomass and biochemical composition. Total carbohydrates, total proteins, total lipids, as well as individual amino acid proportions were determined. The combination of Cd stress and N limitation significantly inhibited growth rate and cell density of C. vulgaris. However, increasing N limitation and Cd stress stimulated higher dry weight and chlorophyll a production per cell. Furthermore, biomolecules like total proteins, carbohydrates and lipids increased with increasing N limitation and Cd stress. Ketogenic and glucogenic amino acids were accumulated under the stress conditions investigated in the present study. Amino acids involved in metal chelation like proline, histidine and glutamine were significantly increased after exposure to combined Cd stress and N limitation. We conclude that N limitation and Cd stress affects the physiology of C. vulgaris by not only decreasing its growth but also stimulating biomolecule production. Copyright © 2015 Elsevier B.V. All rights reserved.

Micrometeorological measurements of ammonia and total reactive nitrogen exchange over semi-natural peatland

Science.gov (United States)

Brümmer, Christian; Richter, Undine; Schrader, Frederik; Kutsch, Werner

2015-04-01

Intensive agriculture generates a substantial atmospheric burden for nitrogen-limited ecosystems such as peatlands when the latter are located in close vicinity to arable sites and animal houses. The exchange of reactive nitrogen compounds between these bog ecosystems and the atmosphere is still not very well understood due to the lack of suitable measurement techniques. With recent advancements in laser spectrometry, we used a quantum cascade laser spectrometer as well as a custom-built total reactive atmospheric nitrogen (ΣNr) converter (TRANC) coupled to a fast-response chemiluminescence detector to measure NH3 and ΣNr concentrations, respectively. The analyzers' high temporal resolution allowed for determination of the respective nitrogen exchange within eddy covariance-based setups. Field campaigns were conducted at a northwestern German peatland site that is surrounded by an area of highly fertilized agricultural land and intensive livestock production (~1 km distance). The field site is part of a natural park with a very small remaining protected zone of less than 2 km x 2 km. Ammonia and ΣNr concentrations were highly variable between 2 to 110 ppb and 10 to 120 ppb, respectively. Peak values coincided with main fertilization periods on the neighboring agricultural land in early spring and fall. The trend in weekly averaged ΣNr concentrations from TRANC measurements was in good agreement with results from KAPS denuder filter systems when the latter were combined with the missing and apparently highly variable NOx contribution. Wind direction and land use in the closer vicinity clearly regulated whether ΣNr concentrations were NH3 or NOx-dominated. Ammonia uptake rates between 40 ng N m-2 s-1 and near-neutral exchange were observed. The cumulative net uptake for the period of investigation was ~700 g N ha-1 resulting in a dry net deposition of ~4 kg N ha-1 when extrapolated to an entire year, whereas KAPS denuder measurements in combination with dry

Characterization of waterborne nitrogen emissions for marine eutrophication modelling in life cycle impact assessment at the damage level and global scale

DEFF Research Database (Denmark)

Cosme, Nuno Miguel Dias; Hauschild, Michael Zwicky

2017-01-01

Current life cycle impact assessment (LCIA) methods lack a consistent and globally applicable characterization model relating nitrogen (N, as dissolved inorganic nitrogen, DIN) enrichment of coastal waters to the marine eutrophication impacts at the endpoint level. This paper introduces a method...... to calculate spatially explicit characterization factors (CFs) at endpoint and damage to ecosystems levels, for waterborne nitrogen emissions, reflecting their hypoxia-related marine eutrophication impacts, modelled for 5772 river basins of the world....

Stable Isotope Identification of Nitrogen Sources for United ...

Science.gov (United States)

We used natural abundance stable isotope data to evaluate nitrogen sources to U.S. west coast estuaries. We collected δ15N of macroalgae data and supplemented this with available data from the literature for estuaries from Mexico to Alaska. Stable isotope ratios of green macroalgae were compared to δ15N of dissolved inorganic nitrogen of oceanic and watershed end members. There was a latitudinal gradient in δ15N of macroalgae with southern estuaries being 7 per mil heavier than northern estuaries. Gradients in isotope data were compared to nitrogen sources estimated by the USGS using the SPARROW model. In California estuaries, the elevation of isotope data appeared to be related to anthropogenic nitrogen sources. In Oregon systems, the nitrogen levels of streams flowing into the estuaries are related to forest cover, rather than to developed land classes. In addition, the δ15N of macroalgae suggested that the ocean and nitrogen-fixing trees in the watersheds were the dominant nitrogen sources. There was also a strong gradient in δ15N of macroalgae with heavier sites located near the estuary mouth. In some Oregon estuaries, there was an elevation an elevation of δ15N above marine end members in the vicinity of wastewater treatment facility discharge locations, suggesting isotopes may be useful for distinguishing inputs along an estuarine gradient. Nutrients are the leading cause of water quality impairments in the United States, and as a result too

Influence of total beam current on HRTEM image resolution in differentially pumped ETEM with nitrogen gas.

Science.gov (United States)

Bright, A N; Yoshida, K; Tanaka, N

2013-01-01

Environmental transmission electron microscopy (ETEM) enables the study of catalytic and other reaction processes as they occur with Angstrom-level resolution. The microscope used is a dedicated ETEM (Titan ETEM, FEI Company) with a differential pumping vacuum system and apertures, allowing aberration corrected high-resolution transmission electron microscopy (HRTEM) imaging to be performed with gas pressures up to 20 mbar in the sample area and with significant advantages over membrane-type E-cell holders. The effect on image resolution of varying the nitrogen gas pressure, electron beam current density and total beam current were measured using information limit (Young's fringes) on a standard cross grating sample and from silicon crystal lattice imaging. As expected, increasing gas pressure causes a decrease in HRTEM image resolution. However, the total electron beam current also causes big changes in the image resolution (lower beam current giving better resolution), whereas varying the beam current density has almost no effect on resolution, a result that has not been reported previously. This behavior is seen even with zero-loss filtered imaging, which we believe shows that the drop in resolution is caused by elastic scattering at gas ions created by the incident electron beam. Suitable conditions for acquiring high resolution images in a gas environment are discussed. Lattice images at nitrogen pressures up to 16 mbar are shown, with 0.12 nm information transfer at 4 mbar. Copyright © 2012 Elsevier B.V. All rights reserved.

Spatial analysis and hazard assessment on soil total nitrogen in the middle subtropical zone of China

Science.gov (United States)

Lu, Peng; Lin, Wenpeng; Niu, Zheng; Su, Yirong; Wu, Jinshui

2006-10-01

Nitrogen (N) is one of the main factors affecting environmental pollution. In recent years, non-point source pollution and water body eutrophication have become increasing concerns for both scientists and the policy-makers. In order to assess the environmental hazard of soil total N pollution, a typical ecological unit was selected as the experimental site. This paper showed that Box-Cox transformation achieved normality in the data set, and dampened the effect of outliers. The best theoretical model of soil total N was a Gaussian model. Spatial variability of soil total N at NE60° and NE150° directions showed that it had a strip anisotropic structure. The ordinary kriging estimate of soil total N concentration was mapped. The spatial distribution pattern of soil total N in the direction of NE150° displayed a strip-shaped structure. Kriging standard deviations (KSD) provided valuable information that will increase the accuracy of total N mapping. The probability kriging method is useful to assess the hazard of N pollution by providing the conditional probability of N concentration exceeding the threshold value, where we found soil total N>2.0g/kg. The probability distribution of soil total N will be helpful to conduct hazard assessment, optimal fertilization, and develop management practices to control the non-point sources of N pollution.

Achieving low effluent NO3-N and TN concentrations in low influent chemical oxygen demand (COD) to total Kjeldahl nitrogen (TKN) ratio without using external carbon source

Science.gov (United States)

Cao, Jiashun; Oleyiblo, Oloche James; Xue, Zhaoxia; Otache, Y. Martins; Feng, Qian

2015-07-01

Two mathematical models were used to optimize the performance of a full-scale biological nutrient removal (BNR) activated treatment plant, a plug-flow bioreactors operated in a 3-stage phoredox process configuration, anaerobic anoxic oxic (A2/O). The ASM2d implemented on the platform of WEST2011 software and the BioWin activated sludge/anaerobic digestion (AS/AD) models were used in this study with the aim of consistently achieving the designed effluent criteria at a low operational cost. Four ASM2d parameters (the reduction factor for denitrification , the maximum growth rate of heterotrophs (µH), the rate constant for stored polyphosphates in PAOs ( q pp), and the hydrolysis rate constant ( k h)) were adjusted. Whereas three BioWin parameters (aerobic decay rate ( b H), heterotrophic dissolved oxygen (DO) half saturation ( K OA), and Y P/acetic) were adjusted. Calibration of the two models was successful; both models have average relative deviations (ARD) less than 10% for all the output variables. Low effluent concentrations of nitrate nitrogen (N-NO3), total nitrogen (TN), and total phosphorus (TP) were achieved in a full-scale BNR treatment plant having low influent chemical oxygen demand (COD) to total Kjeldahl nitrogen (TKN) ratio (COD/TKN). The effluent total nitrogen and nitrate nitrogen concentrations were improved by 50% and energy consumption was reduced by approximately 25%, which was accomplished by converting the two-pass aerobic compartment of the plug-flow bioreactor to anoxic reactors and being operated in an alternating mode. Findings in this work are helpful in improving the operation of wastewater treatment plant while eliminating the cost of external carbon source and reducing energy consumption.

A relevante potencialidade dos centros básicos nitrogenados disponíveis em polímeros inorgânicos e biopol��meros na remoção catiônica The weighty potentiality of nitrogenated basic centers in inorganic polymers and biopolymers for cation removal

Directory of Open Access Journals (Sweden)

Claudio Airoldi

2008-01-01

Full Text Available This review reports the application of inorganic and organic polymeric materials for cation removal by using nitrogenated basic centers. The data demonstrate the importance of the desired groups when free or immobilized on natural or synthesized inorganic polymers through silanol groups. Thus, the most studied silica gel is followed by natural crysotile and talc polymers, and the synthesized mesopore silicas, talc-like, silicic acids, phosphates and phyllosilicates. The organic natural biopolymeric chitin and cellulose were chemically modified to improve the availability of the amine groups or the reactivity with desirable molecules to enlarge the content of basic centers. The cation removal takes place at the solid/liquid interface and some interactive effects have their thermodynamic data determined.

Controls on Biogeochemical Cycling of Nitrogen in Urban Ecosystems

Science.gov (United States)

Templer, P. H.; Hutyra, L.; Decina, S.; Rao, P.; Gately, C.

2017-12-01

Rates of atmospheric nitrogen deposition are declining across much of the United States and Europe, yet they remain substantially elevated by almost an order of magnitude over pre-industrial levels and occur as hot spots in urban areas. We measured atmospheric inputs of inorganic and organic nitrogen in multiple urban sites around the Boston Metropolitan area, finding that urban rates are substantially elevated compared to nearby rural areas, and that the range of these atmospheric inputs are as large as observed urban to rural gradients. Within the City of Boston, the variation in deposition fluxes can be explained by traffic intensity, vehicle emissions, and spring fertilizer additions. Throughfall inputs of nitrogen are approximately three times greater than bulk deposition inputs in the city, demonstrating that the urban canopy amplifies rates of nitrogen reaching the ground surface. Similar to many other metropolitan areas of the United States, the City of Boston has 25% canopy cover; however, 25% of this tree canopy is located above impervious pavement. Throughfall inputs that do not have soil below the canopy to retain excess nitrogen may lead to greater inputs of nitrogen into nearby waterways through runoff. Most measurement stations for atmospheric nitrogen deposition are intentionally located away from urban areas and point sources of pollution to capture regional trends. Our data show that a major consequence of this network design is that hotspots of nitrogen deposition and runoff into urban and coastal waterways is likely underestimated to a significant degree. A more complete determination of atmospheric nitrogen deposition and its fate in urban ecosystems is critical for closing regional nitrogen budgets and for improving our understanding of biogeochemical nitrogen cycling across multiple spatial scales.

Applying fermentation liquid of food waste as carbon source to a pilot-scale anoxic/oxic-membrane bioreactor for enhancing nitrogen removal: Microbial communities and membrane fouling behaviour.

Science.gov (United States)

Tang, Jialing; Wang, Xiaochang C; Hu, Yisong; Ngo, Huu Hao; Li, Yuyou; Zhang, Yongmei

2017-07-01

Fermentation liquid of food waste (FLFW) was applied as an external carbon source in a pilot-scale anoxic/oxic-membrane bioreactor (A/O-MBR) system to enhance nitrogen removal for treating low COD/TN ratio domestic wastewater. Results showed that, with the FLFW addition, total nitrogen removal increased from lower than 20% to 44-67% during the 150days of operation. The bacterial metabolic activities were obviously enhanced, and the significant change in microbial community structure promoted pollutants removal and favored membrane fouling mitigation. By monitoring transmembrane pressure and characterizing typical membrane foulants, such as extracellular polymeric substances (EPS), dissolved organic matter (DOM), and inorganics and biopolymers in the cake layer, it was confirmed that FLFW addition did not bring about any additional accumulation of membrane foulants, acceleration of fouling rate, or obvious irreversible membrane fouling in the whole operation period. Therefore, FLFW is a promising alternative carbon source to enhance nitrogen removal for the A/O-MBR system. Copyright © 2017 Elsevier Ltd. All rights reserved.

Observations of the diurnal and seasonal trends in nitrogen oxides in the western Sierra Nevada

Directory of Open Access Journals (Sweden)

J. G. Murphy

2006-01-01

Full Text Available Observations of speciated nitrogen oxides, namely NO2, total peroxy nitrates (ΣPNs, total alkyl nitrates (ΣANs, and HNO3 by thermal dissociation laser induced fluorescence (TD-LIF, and supporting chemical and meteorological measurements at Big Hill (1860 m, a high elevation site in California's Sierra Nevada Mountains, are described. From May through October, terrain-driven winds in the region routinely bring air from Sacramento, 100 km southwest of the site, upslope over oak and pine forests to Big Hill during the day, while at night, the site often samples clean, dry air characteristic of the free troposphere. Winter differs mainly in that the meteorology does not favour the buildup of Sacramento's pollution over the Sierra Nevada range, and the urban-influenced air that is seen has been less affected by biogenic VOC emissions, resulting in longer lifetime for NO2 and a predominance of the inorganic forms of nitrogen oxides. Summertime observations at Big Hill can be compared with those from Granite Bay, a Sacramento suburb, and from the University of California's Blodgett Forest Research Station to examine the evolution of nitrogen oxides and ozone within the urban plume. Nitrogen oxide radicals (NO and NO2, which dominate total nitrogen oxides (NOy at Granite Bay, are rapidly converted into HNO3, ΣPNs, and ΣANs, such that these compounds contribute 29, 30, and 21% respectively to the NOy budget in the plume at Big Hill. Nevertheless, the decreasing concentrations of NO2 as the plume is advected to Big Hill lead to decreases in the production rate of HNO3 and ozone. The data also demonstrate the role that temperature plays in sequestering NO2 into peroxy nitrates, effectively decreasing the rate of ozone production. The important contribution of ΣANs to NOy in the region suggests that they should be considered with regards to export of NOy from the boundary layer. Nocturnal observations of airmasses characteristic of the

Nitrogen isotopic patterns of vegetation as affected by breeding activity of Black-tailed Gull (Larus crassiostris): A coupled analysis of feces, inorganic soil nitrogen and flora

International Nuclear Information System (INIS)

Mizota, C.

2009-01-01

Two currently breeding colonies (Matsushima Bay and Rishiri island; northern Japan) of predominant Black-tailed Gull (Larus crassiostris) were studied for N isotopic patterns of flora, which is affected by increased supply of inorganic soil N derived from the microbial transformation of feces. Coupled samples of feces, topsoil and flora were collected in early to mid July (2008), when input of fecal N onto soils was at its maximum. As bird migration and breeding continued, native Japanese red-pine (Pinus densiflora), junipers (Juniperus chinensis and Juniperus rigita; Matsushima Bay colony) and Sasa senanensis (Rishiri colony) declined, while ornithocoprophilus exotic plants succeeded. Among tree species on the islands, P. densiflora with ectomycorrizal colonization appears highly susceptible to elevated concentrations of NH 4 -N in the topsoil. A mechanism for best explaining the plant succession associated with the breeding activity of Black-tailed Gull was evidenced by two parameters: first, concomitant elevation of N content in the flora and second, inorganic soil N content, along with changes in N isotopic composition (δ 15 N). Earlier isotopic data on the foliar N affected by breeding activity were compiled and reviewed. Emphasis was put on isotopic information for inorganic N in soils that controls plant succession.

Finite Element Simulation of Total Nitrogen Transport in Riparian Buffer in an Agricultural Watershed

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Xiaosheng Lin

2016-03-01

Full Text Available Riparian buffers can influence water quality in downstream lakes or rivers by buffering non-point source pollution in upstream agricultural fields. With increasing nitrogen (N pollution in small agricultural watersheds, a major function of riparian buffers is to retain N in the soil. A series of field experiments were conducted to monitor pollutant transport in riparian buffers of small watersheds, while numerical model-based analysis is scarce. In this study, we set up a field experiment to monitor the retention rates of total N in different widths of buffer strips and used a finite element model (HYDRUS 2D/3D to simulate the total N transport in the riparian buffer of an agricultural non-point source polluted area in the Liaohe River basin. The field experiment retention rates for total N were 19.4%, 26.6%, 29.5%, and 42.9% in 1,3,4, and 6m-wide buffer strips, respectively. Throughout the simulation period, the concentration of total N of the 1mwide buffer strip reached a maximum of 1.27 mg/cm3 at 30 min, decreasing before leveling off. The concentration of total N about the 3mwide buffer strip consistently increased, with a maximum of 1.05 mg/cm3 observed at 60 min. Under rainfall infiltration, the buffer strips of different widths showed a retention effect on total N transport, and the optimum effect was simulated in the 6mwide buffer strip. A comparison between measured and simulated data revealed that finite element simulation could simulate N transport in the soil of riparian buffer strips.

Negligible contribution of reservoir dams to organic and inorganic transport in the lower Mimi River, Japan

Science.gov (United States)

Nukazawa, Kei; Kihara, Kousuke; Suzuki, Yoshihiro

2017-12-01

Rivers fulfill an essential ecological role by forming networks for material transport from upland forests to coastal areas. The way in which dams affect the organic and inorganic cycles in such systems is not well understood. Herein, we investigated the longitudinal profiles of the various components of the water chemistry across three cascade dams in Japan: the Yamasubaru Dam, Saigou Dam, and Ohuchibaru Dam, which are situated along the sediment-productive Mimi River in different flow conditions. We analyzed the following water quality components: suspended solids (SS), turbidity, total iron (TFe), dissolved iron (DFe), total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), humic substance (HS), and major ionic components (Na+, Mg2+, Ca2+, Cl-, NO3-, and SO42-) in the downstream channels of the three dams during the low-intermediate-flow and high-flow events from 2012 to 2014. We estimated hourly loads of each component using hourly turbidity data and discharge data (i.e., L-Q model) separately, and the results are integrated to estimate the annual fluxes. The annual fluxes between the methods were compared to verify predictability of the conventional L-Q models. Annual flux of TOC, TN, DFe, and HS estimated by the turbidity displayed similar values, whereas the flux of SS, TFe, and TP tended to increase downstream of the dams. Among the dams, estimated flux proportions for TP and TFe were higher during high-flow events (74%-94%). Considering geographic conditions (e.g., absence of major tributary between the dams), the result implies that accumulated TP and TFe in the reservoirs may be flushed and transported downstream with SS over the short height dams during flood events. Assuming this process, the reservoir dams probably make only a fractional contribution to the organic and inorganic transport in the catchment studied. The percent flux errors for SS, TFe, and TP fluxes ranged from -7.2% to -97% (except for the TP flux in 2013), which

Coupled effects of light and nitrogen source on the urea cycle and nitrogen metabolism over a diel cycle in the marine diatom Thalassiosira pseudonana.

Science.gov (United States)

Bender, Sara J; Parker, Micaela S; Armbrust, E Virginia

2012-03-01

Diatoms are photoautotrophic organisms capable of growing on a variety of inorganic and organic nitrogen sources. Discovery of a complete urea cycle in diatoms was surprising, as this pathway commonly functions in heterotrophic organisms to rid cells of waste nitrogen. To determine how the urea cycle is integrated into cellular nitrogen metabolism and energy management, the centric diatom Thalassiosira pseudonana was maintained in semi-continuous batch cultures on nitrate, ammonium, or urea as the sole nitrogen source, under a 16: 8 light: dark cycle and at light intensities that were low, saturating, or high for growth. Steady-state transcript levels were determined for genes encoding enzymes linked to the urea cycle, urea hydrolysis, glutamine synthesis, pyrimidine synthesis, photorespiration, and energy storage. Transcript abundances were significantly affected by nitrogen source, light intensity and a diel cycle. The impact of N source on differential transcript accumulation was most apparent under the highest light intensity. Models of cellular metabolism under high light were developed based on changes in transcript abundance and predicted enzyme localizations. We hypothesize that the urea cycle is integrated into nitrogen metabolism through its connection to glutamine and in the eventual production of urea. These findings have important implications for nitrogen flow in the cell over diel cycles at surface ocean irradiances. Copyright © 2011 Elsevier GmbH. All rights reserved.

Fluxes of oxidised and reduced nitrogen above a mixed coniferous forest exposed to various nitrogen emission sources

Energy Technology Data Exchange (ETDEWEB)

Neirynck, J. [Research Institute for Nature and Forest, Gaverstraat 4, B-9500 Geraardsbergen (Belgium)]. E-mail: johan.neirynck@inbo.be; Kowalski, A.S. [Departamento de Fisica Aplicida, Facultad de Ciencias, Universidad de Granada, Calle Fuentenueva, SP-18071 Granada (Spain); Carrara, A. [Fundacion CEAM, Parque Technologico, Calle Charles H. Darwin 14, SP-46980 Paterna (Valencia) (Spain); Genouw, G. [Research Institute for Nature and Forest, Gaverstraat 4, B-9500 Geraardsbergen (Belgium); Berghmans, P. [Flemish Institute for Technological Research, Boeretang 200, B-2400 Mol (Belgium); Ceulemans, R. [Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk (Antwerp) (Belgium)

2007-09-15

Concentrations of nitrogen gases (NH{sub 3}, NO{sub 2}, NO, HONO and HNO{sub 3}) and particles (pNH{sub 4} and pNO{sub 3}) were measured over a mixed coniferous forest impacted by high nitrogen loads. Nitrogen dioxide (NO{sub 2}) represented the main nitrogen form, followed by nitric oxide (NO) and ammonia (NH{sub 3}). A combination of gradient method (NH{sub 3} and NO {sub x} ) and resistance modelling techniques (HNO{sub 3}, HONO, pNH{sub 4} and pNO{sub 3}) was used to calculate dry deposition of nitrogen compounds. Net flux of NH{sub 3} amounted to -64 ng N m{sup -2} s{sup -1} over the measuring period. Net fluxes of NO {sub x} were upward (8.5 ng N m{sup -2} s{sup -1}) with highest emission in the morning. Fluxes of other gases or aerosols substantially contributed to dry deposition. Total nitrogen deposition was estimated at -48 kg N ha{sup -1} yr{sup -1} and consisted for almost 80% of NH {sub x} . Comparison of throughfall nitrogen with total deposition suggested substantial uptake of reduced N ({+-}15 kg N ha{sup -1} yr{sup -1}) within the canopy. - Reduced nitrogen was found to be the main contributor to total deposition which was predominantly governed by dry deposition.

Composition, sources, and bioavailability of nitrogen in a longitudinal gradient from freshwater to estuarine waters.

Science.gov (United States)

Jani, Jariani; Toor, Gurpal S

2018-06-15

Nitrogen (N) transport from land to water is a dominant contributor of N in estuarine waters leading to eutrophication, harmful algal blooms, and hypoxia. Our objectives were to (1) investigate the composition of inorganic and organic N forms, (2) distinguish the sources and biogeochemical mechanisms of nitrate-N (NO 3 -N) transport using stable isotopes of NO 3 - and Bayesian mixing model, and (3) determine the dissolved organic N (DON) bioavailability using bioassays in a longitudinal gradient from freshwater to estuarine ecosystem located in the Tampa Bay, Florida, United States. We found that DON was the most dominant N form (mean: 64%, range: 46-83%) followed by particulate organic N (PON, mean: 22%, range: 14-37%), whereas inorganic N forms (NO x -N: 7%, NH 4 -N: 7%) were 14% of total N in freshwater and estuarine waters. Stable isotope data of NO 3 - revealed that nitrification was the main contributor (36.4%), followed by soil and organic N sources (25.5%), NO 3 - fertilizers (22.4%), and NH 4 + fertilizers (15.7%). Bioassays showed that 14 to 65% of DON concentrations decreased after 5-days of incubation indicating utilization of DON by microbes in freshwater and estuarine waters. These results suggest that despite low proportion of inorganic N forms, the higher concentrations and bioavailability of DON can be a potential source of N for algae and bacteria leading to water quality degradation in the estuarine waters. Copyright © 2018 Elsevier Ltd. All rights reserved.

Inorganic UV filters

Directory of Open Access Journals (Sweden)

Eloísa Berbel Manaia

2013-06-01

Full Text Available Nowadays, concern over skin cancer has been growing more and more, especially in tropical countries where the incidence of UVA/B radiation is higher. The correct use of sunscreen is the most efficient way to prevent the development of this disease. The ingredients of sunscreen can be organic and/or inorganic sun filters. Inorganic filters present some advantages over organic filters, such as photostability, non-irritability and broad spectrum protection. Nevertheless, inorganic filters have a whitening effect in sunscreen formulations owing to the high refractive index, decreasing their esthetic appeal. Many techniques have been developed to overcome this problem and among them, the use of nanotechnology stands out. The estimated amount of nanomaterial in use must increase from 2000 tons in 2004 to a projected 58000 tons in 2020. In this context, this article aims to analyze critically both the different features of the production of inorganic filters (synthesis routes proposed in recent years and the permeability, the safety and other characteristics of the new generation of inorganic filters.

2013 Gordon Research Conference, Inorganic reaction mechanisms, Galveston, TX, March 3-8 2013

Energy Technology Data Exchange (ETDEWEB)

Abu-Omar, Mahdi M. [Purdue Univ., West Lafayette, IN (United States)

2012-12-08

The 2013 Gordon Conference on Inorganic Reaction Mechanisms will present cutting-edge research on the molecular aspects of inorganic reactions involving elements from throughout the periodic table and state-of-the art techniques that are used in the elucidation of reaction mechanisms. The Conference will feature a wide range of topics, such as homogeneous and heterogeneous catalysis, metallobiochemistry, electron-transfer in energy reactions, polymerization, nitrogen fixation, green chemistry, oxidation, solar conversion, alkane functionalization, organotransition metal chemistry, and computational chemistry. The talks will cover themes of current interest including energy, materials, and bioinorganic chemistry. Sections cover: Electron-Transfer in Energy Reactions; Catalytic Polymerization and Oxidation Chemistry; Kinetics and Spectroscopy of Heterogeneous Catalysts; Metal-Organic Chemistry and its Application in Synthesis; Green Energy Conversion;Organometallic Chemistry and Activation of Small Molecules; Advances in Kinetics Modeling and Green Chemistry; Metals in Biology and Disease; Frontiers in Catalytic Bond Activation and Cleavage.

Export of nitrogen from catchments: A worldwide analysis

International Nuclear Information System (INIS)

Alvarez-Cobelas, M.; Angeler, D.G.; Sanchez-Carrillo, S.

2008-01-01

This study reviews nitrogen export rates from 946 rivers of the world to determine the influence of quantitative (runoff, rainfall, inhabitant density, catchment area, percentage of land use cover, airborne deposition, fertilizer input) and qualitative (dominant type of forest, occurrence of stagnant waterbodies, dominant land use, occurrence of point sources, runoff type) environmental factors on nitrogen fluxes. All fractions (total, nitrate, ammonia, dissolved organic and particulate organic) of nitrogen export showed a left-skewed distribution, which suggests a relatively pristine condition for most systems. Total nitrogen export showed the highest variability whereas total organic nitrogen export comprised the dominant fraction of export. Nitrogen export rates were only weakly explained by our qualitative and quantitative environmental variables. Our study suggests that the consideration of spatial and temporal scales is important for predicting nitrogen export rates using simple and easy-to-get environmental variables. Regionally based modelling approaches prove more useful than global-scale analyses. - Spatial and temporal scales are important determinants for nitrogen export from catchments and emphasis should be put on regional approaches

Strategic adaptation of nitrogen management for el nino southern oscillation-induced winter wheat system

Science.gov (United States)

The rainfall anomaly (RA) associated with El Niño-Southern Oscillation (ENSO) has various unwanted impacts on agricultural system globally. The loss of inorganic nitrogen (N) depending on extreme wet or dry conditions is a major concern. The main objective of this study was to adapt site-specific N ...

Dissolved nitrogen in rivers: comparing pristine and impacted regions of Brazil

Directory of Open Access Journals (Sweden)

LA Martinelli

Full Text Available Riverine nitrogen distribution is increasingly controlled by anthropogenic activities in their watersheds, regardless of spatial scale, climate, and geographical zone. Consequently, modelling efforts to predict the export of nitrogen from rivers worldwide have used attributes such as population density, land use, urbanization and sanitation. These models have greatly enhanced our understanding of the sources and fate of nitrogen added to terrestrial systems and transported to rivers and streams, especially for developed countries of the North temperate zone. However, much of the world's population lives in developing countries of the tropics, where the effects of human activities on riverine N exports are still poorly understood. In an effort to close this gap, we compare riverine nitrogen data from 32 Brazilian rivers draining two contrasting regions in this tropical country in terms of economic development - the State of São Paulo and the Amazon. Our data include nitrogen in different dissolved forms, such as Dissolved Inorganic Nitrogen (DIN and Dissolved Organic Nitrogen (DON. The results show that nitrogen concentrations decreased as river runoff increased in both study areas, and that concentrations were significantly higher in rivers draining the most economically developed region. The relationships between nitrogen concentrations and fluxes with demographic parameters such as population density were also determined and compared to those in temperate systems. In contrast to temperate watersheds, we found that nitrogen fluxes increased only after population densities were higher than 10 individuals per km².

Nitrogen assimilation in denitrifier Bacillus azotoformans LMG 9581T.

Science.gov (United States)

Sun, Yihua; De Vos, Paul; Willems, Anne

2017-12-01

Until recently, it has not been generally known that some bacteria can contain the gene inventory for both denitrification and dissimilatory nitrate (NO 3 - )/nitrite (NO 2 - ) reduction to ammonium (NH 4 + ) (DNRA). Detailed studies of these microorganisms could shed light on the differentiating environmental drivers of both processes without interference of organism-specific variation. Genome analysis of Bacillus azotoformans LMG 9581 T shows a remarkable redundancy of dissimilatory nitrogen reduction, with multiple copies of each denitrification gene as well as DNRA genes nrfAH, but a reduced capacity for nitrogen assimilation, with no nas operon nor amtB gene. Here, we explored nitrogen assimilation in detail using growth experiments in media with different organic and inorganic nitrogen sources at different concentrations. Monitoring of growth, NO 3 - NO 2 - , NH 4 + concentration and N 2 O production revealed that B. azotoformans LMG 9581 T could not grow with NH 4 + as sole nitrogen source and confirmed the hypothesis of reduced nitrogen assimilation pathways. However, NH 4 + could be assimilated and contributed up to 50% of biomass if yeast extract was also provided. NH 4 + also had a significant but concentration-dependent influence on growth rate. The mechanisms behind these observations remain to be resolved but hypotheses for this deficiency in nitrogen assimilation are discussed. In addition, in all growth conditions tested a denitrification phenotype was observed, with all supplied NO 3 - converted to nitrous oxide (N 2 O).

Isotope studies on the comparative efficiency of nitrogenous sources

Energy Technology Data Exchange (ETDEWEB)

Dev, G; Rennie, D A [Saskatchewan Univ., Saskatoon (Canada). Dept. of Soil Science

1979-03-01

In a growth chamber experiment with /sup 15/N-labelled potassium nitrate, ammonium sulphate and urea at 75 and 150kg nitrogen/ha and ammonium nitrate at 150kg nitrogen/ha, nitrogen application produced significant responses of dry matter yield and total nitrogen uptake by shoot and root of barley in chernozemic dark brown Elstow silt loam and deep black Hoey clay soil. Total nitrogen removal per pot and isotope-derived criteria, viz. percentage nitrogen derived from fertilizer, 'A' value and percentage fertilizer nitrogen utilization, indicated that potassium nitrate was the most efficient and urea the least.

Source partitioning of anthropogenic groundwater nitrogen in a mixed-use landscape, Tutuila, American Samoa

Science.gov (United States)

Shuler, Christopher K.; El-Kadi, Aly I.; Dulai, Henrietta; Glenn, Craig R.; Fackrell, Joseph

2017-12-01

This study presents a modeling framework for quantifying human impacts and for partitioning the sources of contamination related to water quality in the mixed-use landscape of a small tropical volcanic island. On Tutuila, the main island of American Samoa, production wells in the most populated region (the Tafuna-Leone Plain) produce most of the island's drinking water. However, much of this water has been deemed unsafe to drink since 2009. Tutuila has three predominant anthropogenic non-point-groundwater-pollution sources of concern: on-site disposal systems (OSDS), agricultural chemicals, and pig manure. These sources are broadly distributed throughout the landscape and are located near many drinking-water wells. Water quality analyses show a link between elevated levels of total dissolved groundwater nitrogen (TN) and areas with high non-point-source pollution density, suggesting that TN can be used as a tracer of groundwater contamination from these sources. The modeling framework used in this study integrates land-use information, hydrological data, and water quality analyses with nitrogen loading and transport models. The approach utilizes a numerical groundwater flow model, a nitrogen-loading model, and a multi-species contaminant transport model. Nitrogen from each source is modeled as an independent component in order to trace the impact from individual land-use activities. Model results are calibrated and validated with dissolved groundwater TN concentrations and inorganic δ15N values, respectively. Results indicate that OSDS contribute significantly more TN to Tutuila's aquifers than other sources, and thus should be prioritized in future water-quality management efforts.

Reference book for the nitrogen industry worker in two volumes, volume 1

Science.gov (United States)

1982-05-01

The first volume presents the physical and chemical properties of gaseous and liquid substances used and obtained at the nitrogen industry enterprises. It describes the different methods for producing and purifying production gases (nitrogen-hydrogen mixture, gas synthesis). It examines the physical and chemical properties of the processes of amonia and methanol synthesis, the industrial plans and the principles for automating them. Certain methods are given for technological calculations, characteristics of the catalysts are presented, and the employed equipment is described. It is designed for engineering-technical workers of enterprises of the nitrogen and other sectors of industry, for specialists working in the scientific research and planning institutes, design offices and other organizations, as well as for teachers of higher educational institutions and students specializing in the field of the technology of inorganic products.

Preparation, morphologies and thermal behavior of high nitrogen compound 2-amino-4,6-diazido-s-triazine and its derivatives

Czech Academy of Sciences Publication Activity Database

Yan, Q.-L.; Musil, T.; Zeman, S.; Matyáš, R.; Shi, X.-B.; Vlček, Milan; Pelikán, V.

2015-01-01

Roč. 604, 20 March (2015), s. 106-114 ISSN 0040-6031 Institutional support: RVO:61389013 Keywords : azido-s-triazine * decomposition * high nitrogen compounds Subject RIV: CA - Inorganic Chemistry Impact factor: 1.938, year: 2015

Evaluation of automated analysis of 15N and total N in plant material and soil

DEFF Research Database (Denmark)

Jensen, E.S.

1991-01-01

Simultaneous determination of N-15 and total N using an automated nitrogen analyser interfaced to a continuous-flow isotope ratio mass spectrometer (ANA-MS method) was evaluated. The coefficient of variation (CV) of repeated analyses of homogeneous standards and samples at natural abundance...... was lower than 0.1%. The CV of repeated analyses of N-15-labelled plant material and soil samples varied between 0.3% and 1.1%. The reproducibility of repeated total N analyses using the automated method was comparable to results obtained with a semi-micro Kjeldahl procedure. However, the automated method...... analysis showed that the recovery of inorganic N in the NH3 trap was lower when the N was diffused from water than from 2 M KCl. The results also indicated that different proportions of the NO3- and the NH4+ in aqueous solution were recovered in the trap after combined diffusion. The method is most suited...

Biomedical inorganic polymers bioactivity and applications of natural and synthetic polymeric inorganic molecules

CERN Document Server

Müller, Werner E G; Schröder, Heinz C; Schroder, Heinz C

2014-01-01

In recent years, inorganic polymers have attracted much attention in nano-biomedicine, in particular in the area of regenerative medicine and drug delivery. This growing interest in inorganic polymers has been further accelerated by the development of new synthetic and analytical methods in the field of nanotechnology and nanochemistry. Examples for biomedical inorganic polymers that had been proven to exhibit biomedical effects and/or have been applied in preclinical or clinical trials are polysilicate / silica glass (such as naturally formed "biosilica" and synthetic "bioglass") and inorganic polyphosphate. Some members of the mentioned biomedical inorganic polymers have already been applied e.g. as "bioglass" for bone repair and bone tissue engineering, or they are used in food processing and in dental care (inorganic polyphosphates). However, there are a number of further biological and medicinal properties of these polymers, which have been elucidated in the last few years but not yet been applied for tr...

Air pollution: Tropospheric ozone, and wet deposition of sulfate and inorganic nitrogen

Science.gov (United States)

John W. Coulston

2009-01-01

The influence of air pollutants on ecosystems in the United States is an important environmental issue. The term “air pollution” encompasses a wide range of topics, but acid deposition and ozone are primary concerns in the context of forest health. Acid deposition partially results from emissions of sulfur dioxide, nitrogen oxides, and ammonia that are deposited in wet...

Inorganic arsenic exposure and type 2 diabetes mellitus in Mexico

International Nuclear Information System (INIS)

Coronado-Gonzalez, Jose Antonio; Razo, Luz Maria del; Garcia-Vargas, Gonzalo; Sanmiguel-Salazar, Francisca; Escobedo-de la Pena, Jorge

2007-01-01

Inorganic arsenic exposure in drinking water has been recently related to diabetes mellitus. To evaluate this relationship the authors conducted in 2003, a case-control study in an arseniasis-endemic region from Coahuila, a northern state of Mexico with a high incidence of diabetes. The present analysis includes 200 cases and 200 controls. Cases were obtained from a previous cross-sectional study conducted in that region. Diagnosis of diabetes was established following the American Diabetes Association criteria, with two fasting glucose values ≥126 mg/100 ml (≥7.0 mmol/l) or a history of diabetes treated with insulin or oral hypoglycemic agents. The next subject studied, subsequent to the identification of a case in the cross-sectional study was taken as control. Inorganic arsenic exposure was measured through total arsenic concentrations in urine, measured by hydride-generation atomic absorption spectrophotometry. Subjects with intermediate total arsenic concentration in urine (63.5-104 μg/g creatinine) had two-fold higher risk of having diabetes (odds ratio=2.16; 95% confidence interval: 1.23, 3.79), but the risk was almost three times greater in subjects with higher concentrations of total arsenic in urine (odds ratio=2.84; 95% confidence interval: 1.64, 4.92). This data provides additional evidence that inorganic arsenic exposure may be diabetogenic

Carbon and nitrogen stocks and forms of N in a red dysthropic argisol grown or not with peanut forage

Directory of Open Access Journals (Sweden)

Valdinei Tadeu Paulino

2012-12-01

Full Text Available The low availability of nitrogen (N is considered one of the most limiting factors for the productivity of pastures, often responsible for their degradation. Overall, due to the high cost of nitrogen fertilizers, it is not applied in sufficient quantities. In this context, the cultivation of legumes is an option for adding nitrogen in the soil and simultaneously is into high-protein food. Forage legume may reduce the emission of greenhouse gases, changing nutrient cycling (C and N and can improve productivity and sustainability of agricultural systems. Most of the N in the soil is in the organic form compounds, that is converted into inorganic fraction, the predominant mineral forms of nitrogen (NH4+ and NO3-, available to plants by mineralization process. The C:N ratios from soil and plant residues affect the decomposition rate and the balance between N mineralization and N immobilization by microbes. The aim of this study was to evaluate the improvements in soil quality by comparing the forage legume Arachis pintoi cv. Belmonte, cultivated for eight years and a bare soil - an adjacent area (AA in a soil Ultissol (Red Dysthrophic argisol. We evaluated the levels and stocks of C, total N and C:N, NH4+ and NO3- in soil from a depth of 0-20 cm. The experimental design was a randomized complete block with ten replications. Variance analysis (ANOVA was used to detect significant differences between the study areas, averages were compared using test for multiple comparisons Student Newman-Keuls - SNK test (p < 0.05. Analyses were performed using SAS (2010. The availability of mineral N in uncultivated area was low, with mean values below 10 mg kg-1 for both nitrate and ammonium, possibly due to the low organic matter content (17.8 g kg-1. However, under the cultivation of the peanut forage there were increases (p < 0.05 of the contents and stocks of C and N, and the levels of ammonium and nitrate. Increases in total N and inorganic N forms are the

Influence of surface chemistry of carbon materials on their interactions with inorganic nitrogen contaminants in soil and water.

Science.gov (United States)

Sumaraj; Padhye, Lokesh P

2017-10-01

Inorganic nitrogen contaminants (INC) (NH 4 + , NO 3 - , NO 2 - , NH 3 , NO, NO 2 , and N 2 O) pose a growing risk to the environment, and their remediation methods are highly sought after. Application of carbon materials (CM), such as biochar and activated carbon, to remediate INC from agricultural fields and wastewater treatment plants has gained a significant interest since past few years. Understanding the role of surface chemistry of CM in adsorption of various INC is highly critical to increase adsorption efficiency as well as to assess the long term impact of using these highly recalcitrant CM for remediation of INC. Critical reviews of adsorption studies related to INC have revealed that carbon surface chemistry (surface functional groups, pH, Eh, elemental composition, and mineral content) has significant influence on adsorption of INC. Compared to basic functional groups, oxygen containing surface functional groups have been found to be more influential for adsorption of INC. However, basic sites on carbon materials still play an important role in chemisorption of anionic INC. Apart from surface functional groups, pH, Eh and pH zpc of CM and elemental and mineral composition of its surface are important properties capable of altering INC interactions with CM. This review summarizes our current understanding of INC interactions with CM's surface through the known chemisorption mechanisms: electrostatic interaction, hydrogen bonding, electron donor-acceptor mechanism, hydrophobic and hydrophilic interaction, chemisorption aided by minerals, and interactions influenced by pH and elemental composition. Change in surface chemistry of CM in soil during aging is also discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

A comparison of product yields and inorganic content in process streams following thermal hydrolysis and hydrothermal processing of microalgae, manure and digestate.

Science.gov (United States)

Ekpo, U; Ross, A B; Camargo-Valero, M A; Williams, P T

2016-01-01

Thermal hydrolysis and hydrothermal processing show promise for converting biomass into higher energy density fuels. Both approaches facilitate the extraction of inorganics into the aqueous product. This study compares the behaviour of microalgae, digestate, swine and chicken manure by thermal hydrolysis and hydrothermal processing at increasing process severity. Thermal hydrolysis was performed at 170°C, hydrothermal carbonisation (HTC) was performed at 250°C, hydrothermal liquefaction (HTL) was performed at 350°C and supercritical water gasification (SCWG) was performed at 500°C. The level of nitrogen, phosphorus and potassium in the product streams was measured for each feedstock. Nitrogen is present in the aqueous phase as organic-N and NH3-N. The proportion of organic-N is higher at lower temperatures. Extraction of phosphorus is linked to the presence of inorganics such as Ca, Mg and Fe in the feedstock. Microalgae and chicken manure release phosphorus more easily than other feedstocks. Copyright © 2015. Published by Elsevier Ltd.

Fractionation of Nitrogen Isotopes by Plants with Different Types of Mycorrhiza in Mountain Tundra Ecosystems

Science.gov (United States)

Buzin, Igor; Makarov, Mikhail; Maslov, Mikhail; Tiunov, Alexei

2017-04-01

We studied nitrogen concentration and nitrogen isotope composition in plants from four mountain tundra ecosystems in the Khibiny Mountains. The ecosystems consisted of a toposequence beginning with the shrub-lichen heath (SLH) on the ridge and upper slope, followed by the Betula nana dominated shrub heath (SH) on the middle slope, the cereal meadow (CM) on the lower slope and the sedge meadow (SM) at the bottom of the slope. The inorganic nitrogen concentration of the soils from the studied ecosystems were significantly different; the SLH soil was found to contain the minimum concentration of N-NH4+ and N-NO3- , while in the soils of the meadow ecosystems these concentrations were much higher. The concentration of nitrogen in leaves of the dominant plant species in all of the ecosystems is directly connected with the concentration of inorganic nitrogen in the soils, regardless of the plant's mycorrhizal symbiosis type. However, such a correlation is not apparent in the case of plant roots, especially for plant roots with ectomycorrhiza and ericoid mycorrhiza. The majority of plant species with these types of mycorrhiza in the SH and particularly in the CM were enriched in 15N in comparison with the SLH (such plants were not found within the SM). This could be due to several reasons: 1) the decreasing role of mycorrhiza in nitrogen consumption and therefore in the fractionation of isotopes in the relatively-N-enriched ecosystems; 2) the use of relatively-15N-enriched forms of nitrogen for plant nutrition in meadow ecosystems. This heavier nitrogen isotope composition in plant roots with ectomycorrhiza and ericoid mycorrhiza in ecosystems with available nitrogen enriched soils doesn't correspond to the classical idea of mycorrhiza decreasing participation in nitrogen plant nutrition. The analysis of the isotope composition of separate labile forms of nitrogen makes it possible to explain the phenomenon. Not all arbuscular mycorrhizal species within the sedge meadow

Combined nitrogen limitation and cadmium stress stimulate total carbohydrates, lipids, protein and amino acid accumulation in Chlorella vulgaris (Trebouxiophyceae)

Energy Technology Data Exchange (ETDEWEB)

Chia, Mathias Ahii, E-mail: chia28us@yahoo.com [Department of Botany, Federal University of São Carlos, Rodovia Washington Luis km 235, São Carlos, SP Cep 13565905 (Brazil); Lombardi, Ana Teresa [Department of Botany, Federal University of São Carlos, Rodovia Washington Luis km 235, São Carlos, SP Cep 13565905 (Brazil); Graça Gama Melão, Maria da [Department of Hydrobiology, Federal University of São Carlos, Rodovia Washington Luis km 235, São Carlos, SP Cep 13565905 (Brazil); Parrish, Christopher C. [Department of Ocean Sciences, Memorial University of Newfoundland, St. John’s, Newfoundland A1C 5S7 (Canada)

2015-03-15

Highlights: • Chlorella vulgaris was exposed to Cd under varying N concentrations. • Growth rate and cell density decreased with increasing Cd stress and N limitation. • Dry weight, chlorophyll a, total lipid, carbohydrate and protein were accumulated. • Amino acids like proline and glutamine were accumulated under N and Cd stress. • Changes in amino acid composition are sensitive biomarkers for Cd and N stress. - Abstract: Metals have interactive effects on the uptake and metabolism of nutrients in microalgae. However, the effect of trace metal toxicity on amino acid composition of Chlorella vulgaris as a function of varying nitrogen concentrations is not known. In this research, C. vulgaris was used to investigate the influence of cadmium (10{sup −7} and 2.0 × 10{sup −8} mol L{sup −1} Cd) under varying nitrogen (2.9 × 10{sup −6}, 1.1 × 10{sup −5} and 1.1 × 10{sup −3} mol L{sup −1} N) concentrations on its growth rate, biomass and biochemical composition. Total carbohydrates, total proteins, total lipids, as well as individual amino acid proportions were determined. The combination of Cd stress and N limitation significantly inhibited growth rate and cell density of C. vulgaris. However, increasing N limitation and Cd stress stimulated higher dry weight and chlorophyll a production per cell. Furthermore, biomolecules like total proteins, carbohydrates and lipids increased with increasing N limitation and Cd stress. Ketogenic and glucogenic amino acids were accumulated under the stress conditions investigated in the present study. Amino acids involved in metal chelation like proline, histidine and glutamine were significantly increased after exposure to combined Cd stress and N limitation. We conclude that N limitation and Cd stress affects the physiology of C. vulgaris by not only decreasing its growth but also stimulating biomolecule production.

Long-term natural attenuation of carbon and nitrogen within a groundwater plume after removal of the treated wastewater source.

Science.gov (United States)

Repert, Deborah A; Barber, Larry B; Hess, Kathryn M; Keefe, Steffanie H; Kent, Douglas B; LeBlanc, Denis R; Smith, Richard L

2006-02-15

Disposal of treated wastewater for more than 60 years onto infiltration beds on Cape Cod, Massachusetts produced a groundwater contaminant plume greater than 6 km long in a surficial sand and gravel aquifer. In December 1995 the wastewater disposal ceased. A long-term, continuous study was conducted to characterize the post-cessation attenuation of the plume from the source to 0.6 km downgradient. Concentrations and total pools of mobile constituents, such as boron and nitrate, steadily decreased within 1-4 years along the transect. Dissolved organic carbon loads also decreased, but to a lesser extent, particularly downgradient of the infiltration beds. After 4 years, concentrations and pools of carbon and nitrogen in groundwater were relatively constant with time and distance, but substantially elevated above background. The contaminant plume core remained anoxic for the entire 10-year study period; temporal patterns of integrated oxygen deficit decreased slowly at all sites. In 2004, substantial amounts of total dissolved carbon (7 mol C m(-2)) and fixed (dissolved plus sorbed) inorganic nitrogen (0.5 mol N m(-2)) were still present in a 28-m vertical interval at the disposal site. Sorbed constituents have contributed substantially to the dissolved carbon and nitrogen pools and are responsible for the long-term persistence of the contaminant plume. Natural aquifer restoration at the discharge location will take at least several decades, even though groundwater flow rates and the potential for contaminant flushing are relatively high.

Automated atomic absorption spectrometric determination of total arsenic in water and streambed materials

Science.gov (United States)

Fishman, M.

1977-01-01

An automated method to determine both inorganic and organic forms of arsenic In water, water-suspended mixtures, and streambed materials Is described. Organic arsenic-containing compounds are decomposed by either ultraviolet radiation or by suHurlc acid-potassium persulfate digestion. The arsenic liberated, with Inorganic arsenic originally present, is reduced to arsine with sodium borohydrlde. The arable Is stripped from the solution with the aid of nitrogen and Is then decomposed In a tube furnace heated to 800 ??C which Is placed in the optical path of an atomic absorption spectrometer. Thirty samples per hour can be analyzed to levels of 1 ??g arsenic per liter.

Dynamics of N-NH4 +, N-NO3 -, and total soil nitrogen in paddy field with azolla and biochar

Science.gov (United States)

Dewi, W. S.; Wahyuningsih, G. I.; Syamsiyah, J.; Mujiyo

2018-03-01

Nitrogen (N) is one of macronutrients which is dynamic in the soil and becomes constraint factor for rice crops. The addition of nitrogen fertilizers and its absorption in paddy field causes the dynamics of nitrogen, thus declines of N absorption efficiency. The aim of this research is to know influence Azolla, biochar and different varieties application on N-NH4 +, N-NO3 -, and total soil N in paddy field. This research was conducted in a screen house located in Jumantono Laboratory, Faculty of Agriculture, Universitas Sebelas Maret (UNS) with altitude 170 m asl from April to June 2016. Treatment factors that were examined consisted of azolla (0 and 10 tons/ha), biochar (0 and 2 tons/ha), and rice varieties (Cisadane, Memberamo, Ciherang, IR64). The results of this research showed that there was no interaction between azolla, biochar and varieties. Nevertheless, azolla treatment with dose of 10 tons/ha increased soil NH4 + content (41 days after planting, DAP) by 13.4% but tend to decrease at 70 and 90 DAP. Biochar treatment with dose of 2 ton/ha increases NO3 - soil content (70 DAP) by 1.7% but decreases total N soil by 5.8% (41 DAP) and 4.7% (90 DAP). Different rice varieties generated different soil NH4 + content (41 DAP) and rice root volume. Cisadane variety can increase soil NH4 + content (41 DAP) by 52.08% and root volume by 51.80% (90 DAP) compared with Ciherang variety. Organic rice field management with azolla and biochar affects the availability of N in the soil and increase N absorption efficiency through its role in increasing rice root volume.

Speciative determination of total V and dissolved inorganic vanadium species in environmental waters by catalytic–kinetic spectrophotometric method

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Ramazan Gürkan

2017-02-01

Full Text Available A kinetic determination of V(V as a catalyst was spectrophotometrically performed by using the indicator reaction of Gallamine blue (GB+ and bromate at pH 2.0. The reaction was followed by measuring absorbance change for a fixed-time of 3 min at 537 nm. The variables such as reagent concentration, pH, buffer concentration, ionic strength and temperature were optimized to improve the selectivity and sensitivity. Under the optimized conditions, the determination of V(V was performed in the range 1–100 μg L−1 with limits of detection and quantification of 0.31 and 0.94 μg L−1. The developed kinetic method is sufficiently sensitive, selective and simple. It was successfully applied to the speciative determination of total V and inorganic dissolved vanadium species, V(V and V(IV in environmental water samples. The oxidizing property of permanganate is used to differentiate between V(IV and V(V species. The V(IV content was found by subtracting the V(V content from those of total V. The recovery is above 95% for V(V spiked samples. Additionally, the accuracy was validated by analysis of a certified water sample, CRM TMDA-53.3, and the results were in good agreement with the certified value.

Field estimation of the utilization coefficient of added inorganic nitrogen by sugar-beets

International Nuclear Information System (INIS)

Lindemann, Y.; Guiraud, G.; Christmann, J.; Auge, G.

1981-07-01

Fertilization with mineral nitrogen labelled with the 15 isotope permits, in the crop, the estimation of both: - the real utilization coefficient of N fertilizer, - the uptake of the available N issued from organic matter. In 1979, such an experiment was carried out on sugar beet in Beauce on a long term field experiment including 7 N.P.K. treatments with 4 repetitions. Each plot was divided into 2 parts to constitute a treatment N=0 for the estimation of the apparent utilization coefficient. In addition, 4 microplots (size: 8 m 2 ) received a labelled fertilizer for the measurement of the actual coefficients. The results obtained show the incoherence of the apparent coefficients, which are higher than 100%. The real coefficients are from 40 to 80%. Thus, the balance sheet for the input and output of mineral nitrogen is established precisely. The gross mineralization can be much more important than the net mineralization [fr

15N-labeled nitrogen from green manure and ammonium sulfate utilization by the sugarcane ratoon

International Nuclear Information System (INIS)

Ambrosano, Edmilson Jose; Rossi, Fabricio; Trivelin, Paulo Cesar Ocheuze; Cantarella, Heitor; Ambrosano, Glaucia Maria Bovi; Schammass, Eliana Aparecida; Muraoka, Takashi

2011-01-01

Legumes as green manure are alternative sources of nitrogen (N) for crops and can supplement or even replace mineral nitrogen fertilization due to their potential for biological nitrogen fixation (BNF). The utilization of nitrogen by sugarcane (Saccharum spp.) fertilized with sunn hemp (Crotalaria juncea L.) and ammonium sulfate (AS) was evaluated using the 15 N tracer technique. N was added at the rate of 196 and 70 kg ha -1 as 15 N-labeled sunn hemp green manure (SH) and as ammonium sulfate (AS), respectively. Treatments were: (I) Control; (II) AS 15 N; (III) SH 15 N + AS; (IV) SH 15 N; and (V) AS 15 N + SH. Sugarcane was cultivated for five years and was harvested three times. 15 N recovery was evaluated in the two first harvests. In the sum of the three harvests, the highest stalk yields were obtained with a combination of green manure and inorganic N fertilizer; however, in the second cutting the yields were higher where SH was used than in plots with AS. The recovery of N by the first two consecutive harvests accounted for 19 to 21% of the N applied as leguminous green manure and 46 to 49% of the N applied as AS. The amounts of inorganic N, derived from both N sources, present in the 0-0.4 m layer of soil in the first season after N application and were below 1 kg ha -1 . (author)

Efficacy of reactive mineral-based sorbents for phosphate, bacteria, nitrogen and TOC removal--column experiment in recirculation batch mode.

Science.gov (United States)

Nilsson, Charlotte; Lakshmanan, Ramnath; Renman, Gunno; Rajarao, Gunaratna Kuttuva

2013-09-15

Two mineral-based materials (Polonite and Sorbulite) intended for filter wells in on-site wastewater treatment were compared in terms of removal of phosphate (PO4-P), total inorganic nitrogen (TIN), total organic carbon (TOC) and faecal indicator bacteria (Escherichia coli and Enterococci). Using an innovative, recirculating system, septic tank effluent was pumped at a hydraulic loading rate of 3000 L m(2) d(-1) into triplicate bench-scale columns of each material over a 90-day period. The results showed that Polonite performed better with respect to removal of PO4-P, retaining on average 80% compared with 75% in Sorbulite. This difference was attributed to higher CaO content in Polonite and its faster dissolution. Polonite also performed better in terms of removal of bacteria because of its higher pH value. The total average reduction in E. coli was 60% in Polonite and 45% in Sorbulite, while for Enterococci the corresponding value was 56% in Polonite and 34% in Sorbulite. Sorbulite removed TIN more effectively, with a removal rate of 23%, while Polonite removed 11% of TIN, as well as TOC. Organic matter (measured as TOC) was accumulated in the filter materials but was also released periodically. The results showed that Sorbulite could meet the demand in removing phosphate and nitrogen with reduced microbial release from the wastewater treatment process. Copyright © 2013 Elsevier Ltd. All rights reserved.

Crop growth and nitrogen turnover under increased temperatures and low autumn and winter light intensity

DEFF Research Database (Denmark)

Thomsen, Ingrid Kaag; Lægdsmand, Mette; Olesen, Jørgen E

2010-01-01

The rise in mean annual temperatures under the projected climate change will affect both soil organic matter turnover and cropping patterns in agriculture. Nitrogen (N) mineralization may be higher during autumn and winter and may increase the risk of nitrate leaching. Our study tested whether...... before the late sowing of wheat caused generally higher levels of inorganic N to accumulate in soil. Despite the higher mineralization under the raised temperatures, at T+8 the late-sown winter wheat was able to reduce soil inorganic N to a lower level than late-sown wheat at the two lower temperatures...

Total Nitrogen Sources of the Three Gorges Reservoir--A Spatio-Temporal Approach.

Directory of Open Access Journals (Sweden)

Chunping Ren

Full Text Available Understanding the spatial and temporal variation of nutrient concentrations, loads, and their distribution from upstream tributaries is important for the management of large lakes and reservoirs. The Three Gorges Dam was built on the Yangtze River in China, the world's third longest river, and impounded the famous Three Gorges Reservoir (TGR. In this study, we analyzed total nitrogen (TN concentrations and inflow data from 2003 till 2010 for the main upstream tributaries of the TGR that contribute about 82% of the TGR's total inflow. We used time series analysis for seasonal decomposition of TN concentrations and used non-parametric statistical tests (Kruskal-Walli H, Mann-Whitney U as well as base flow segmentation to analyze significant spatial and temporal patterns of TN pollution input into the TGR. Our results show that TN concentrations had significant spatial heterogeneity across the study area (Tuo River> Yangtze River> Wu River> Min River> Jialing River>Jinsha River. Furthermore, we derived apparent seasonal changes in three out of five upstream tributaries of the TGR rivers (Kruskal-Walli H ρ = 0.009, 0.030 and 0.029 for Tuo River, Jinsha River and Min River in sequence. TN pollution from non-point sources in the upstream tributaries accounted for 68.9% of the total TN input into the TGR. Non-point source pollution of TN revealed increasing trends for 4 out of five upstream tributaries of the TGR. Land use/cover and soil type were identified as the dominant driving factors for the spatial distribution of TN. Intensifying agriculture and increasing urbanization in the upstream catchments of the TGR were the main driving factors for non-point source pollution of TN increase from 2003 till 2010. Land use and land cover management as well as chemical fertilizer use restriction were needed to overcome the threats of increasing TN pollution.

In vivo prompt gamma activation analysis facility for total body nitrogen and cadmium

International Nuclear Information System (INIS)

Munive, Marco; Solis, Jose; Revilla, Angel

2008-01-01

Full text: Prompt Neutron Activation Analysis (PGNAA) is a technique that could have medical applications, like determination of body's contents of protein and heavy metals in vivo. The in vivo PGNAA facility, contains a neutron source (Cf-252) with safety device, a compartment for animal irradiation, and a gamma rays detecting system based on the NaI(Tl) detector with an analytical software. The prompt gamma rays were emitted after 10 -15 s of the interaction, so they don't produce radioactive waste, and have a characteristics energy for each element, i.e. a strong peak at 2.24 MeV is observed for H. The facility has been used with laboratory mice. Water-filled phantom placed in the neutron beam was used to system calibration. Three study groups of 5 mice each one were selected and were feed with a different diet and the total body nitrogen (TBN) of the mice was monitored with the facility. The diet produced a different TBN for each group. Some mice drunk diluted water with Cl 2 Cd, so the presence of Cd was detected in the mouse. The minimum Cd concentration that the system can detect was 20 ppm. The total dose (neutron and gamma dose was measured from TLDs and simulated by MNCP-4B in the sample compartment during the irradiation time (5 minutes) is less than 2.5 mSv. This total dose is low than the dose from other analytical radiological techniques (25 a 50 mSv). (author)

Inorganic pigment study of the San Pedro Gonzalez Telmo Sibyls using total reflection X-ray fluorescence

International Nuclear Information System (INIS)

Vazquez, Cristina; Custo, Graciela; Barrio, Nestor; Burucua, Jose; Boeykens, Susana; Marte, Fernando

2010-01-01

This article describes the study carried out on a series of oil paintings on canvas from the eighteenth century that were restored at Centro de Produccion e Investigacion en Restauracion y Conservacion Artistica y Bibliografica - Tarea (CEIRCAB-Tarea), Buenos Aires, Argentina: the San Pedro Gonzalez Telmo Sibyls. Experimental study was undertaken to identify inorganic pigments and the technique used in their confection; and, in this way, try to add information about their local origin. Therefore special emphasis was put to infer technologies used in the manufacturing of these paintings. Elemental analysis was performed by total reflection X-ray fluorescence spectrometry (TXRF) and complemented by optical and polarized light microscopy. Microsampling was carefully done over areas of the paintings which were damaged and where a small additional loss will not be noticed. This investigation has shown that a variety of pigments were used, namely earth pigments (red and yellow ochres), white lead, vermilion, etc., and they were used either pure or in mixtures. This characterization helped conservators in their decisions regarding a better understanding of the deterioration processes. In addition, this research about the material composition allowed the art historians and restorers the possibility to obtain information about where, when or by whom The San Pedro Gonzalez Telmo Sibyls may have been painted.

Inorganic pigment study of the San Pedro Gonzalez Telmo Sibyls using total reflection X-ray fluorescence

Energy Technology Data Exchange (ETDEWEB)

Vazquez, Cristina, E-mail: vazquez@cnea.gov.a [Universidad de Buenos Aires, Facultad de Ingenieria, Paseo Colon 850. C1063ACU, Buenos Aires (Argentina); Comision Nacional de Energia Atomica, Gerencia Quimica, Av. Gral Paz 1499, B1650KNA, San Martin (Argentina); Custo, Graciela, E-mail: custo@cnea.gov.a [Comision Nacional de Energia Atomica, Gerencia Quimica, Av. Gral Paz 1499, B1650KNA, San Martin (Argentina); Barrio, Nestor, E-mail: nbarrio@unsam.edu.a [CEIRCAB-TAREA, Universidad Nacional de San Martin (UNSAM), Escuela de Humanidades, Campus Miguelete, 25 de Mayo y Francia, B1650KNA, San Martin (Argentina); Burucua, Jose, E-mail: gburucua@unsam.edu.a [CEIRCAB-TAREA, Universidad Nacional de San Martin (UNSAM), Escuela de Humanidades, Campus Miguelete, 25 de Mayo y Francia, B1650KNA, San Martin (Argentina); Boeykens, Susana [Universidad de Buenos Aires, Facultad de Ingenieria, Paseo Colon 850. C1063ACU, Buenos Aires (Argentina); Marte, Fernando, E-mail: fmarte@unsam.edu.a [CEIRCAB-TAREA, Universidad Nacional de San Martin (UNSAM), Escuela de Humanidades, Campus Miguelete, 25 de Mayo y Francia, B1650KNA, San Martin (Argentina)

2010-09-15

This article describes the study carried out on a series of oil paintings on canvas from the eighteenth century that were restored at Centro de Produccion e Investigacion en Restauracion y Conservacion Artistica y Bibliografica - Tarea (CEIRCAB-Tarea), Buenos Aires, Argentina: the San Pedro Gonzalez Telmo Sibyls. Experimental study was undertaken to identify inorganic pigments and the technique used in their confection; and, in this way, try to add information about their local origin. Therefore special emphasis was put to infer technologies used in the manufacturing of these paintings. Elemental analysis was performed by total reflection X-ray fluorescence spectrometry (TXRF) and complemented by optical and polarized light microscopy. Microsampling was carefully done over areas of the paintings which were damaged and where a small additional loss will not be noticed. This investigation has shown that a variety of pigments were used, namely earth pigments (red and yellow ochres), white lead, vermilion, etc., and they were used either pure or in mixtures. This characterization helped conservators in their decisions regarding a better understanding of the deterioration processes. In addition, this research about the material composition allowed the art historians and restorers the possibility to obtain information about where, when or by whom The San Pedro Gonzalez Telmo Sibyls may have been painted.

Catchment hydrochemical processes controlling acidity and nitrogen in forest stream water

International Nuclear Information System (INIS)

Foelster, Jens

2001-01-01

Atmospheric deposition of air pollutants has been a severe threat to terrestrial and forest ecosystems for several decades. In Sweden sulphur deposition has caused acidification of soils and runoff, while nitrogen deposition only had a minor or local impact on runoff quality so far. During the last three decades, emission control has caused a decline in sulphur deposition, whereas nitrogen deposition on the other hand, has continued to increase to a rate several times above the natural background level. Long term changes in runoff acidity and nitrogen chemistry after these changes in deposition are of great concern. Monitoring of small, well-defined catchments including hydrochemistry of precipitation, soil and runoff, is a valuable tool for addressing this concern. When interpreting runoff data from such sites, the near-stream zone has been identified to be of crucial importance. The main objective for this thesis was to explain how catchment processes were related to short-term variation and long-term trends in the hydrochemistry of forest stream water. The field work was conducted on the strongly acidified and nitrogen limited Kindla catchment, with a special emphasis on the relationship between the near-stream zone and both stream acidity and nitrogen leaching. Furthermore, time series of hydrochemistry in forest stream water from 13 catchments were analysed for changes in acidity and nitrogen leaching. In three of these sites, soil water from E- and B-horizons was also analysed with regards to these questions. The investigations revealed that the near-stream zone was a net source of acidity in runoff at Kindla due to leaching of organic acids, although this contribution was overshadowed by sulphate from upland soils and deposition. The near-stream zone was also the main source for both organic nitrogen and nitrate to the stream, but the leaching rate was low, especially for inorganic nitrogen. In the 13 reference streams, sulphate concentrations declined in

Nitrogen balance in a hilly semi-agricultural watershed in Northern Italy

Directory of Open Access Journals (Sweden)

Linda Pieri

2011-03-01

Full Text Available The research was carried out for 7 years, 1998-2005, in a semi-agricultural watershed, called Centonara, set within a natural regional park and situated in the hills surrounding Bologna, northern Italy. This area is characterized by one of the most interesting badlands complexes in Europe and represents one of the main points of naturalistic interest. The watershed is partially cultivated (about 30% of the total area with arable crops, mostly cereals and alfalfa. To evaluate the impact of agricultural activity on the eco-sustainability of this area, the nitrogen (N balance was computed. Although it is only an estimation of the potential environmental damage, the nitrogen balance is a useful indicator of the risk posed to the environment from excessive nitrogen and can be useful to understand the possible effects of a certain type of agricultural and environmental management and policy. The balance was calculated by computing the difference between all inputs and all outputs. The nitrogen balance of the watershed was found to be sustainable, with an annual nitrogen balance ranging between –2.3 and +4.4 kg ha–1. Despite the limited presence of arable lands, the agricultural management played the main role in determining the sustainability of the watershed, strongly influencing both the principal N sources and sinks. In fact, major N inputs derived from inorganic fertilization (8.1-15.5 kg ha–1yr–1 and biological fixation (8.3-14.3 kg ha–1yr–1. On the other hand, plant removal constituted the most important output (17.7-25.6 kg ha–1yr–1. N losses in the drainage water were limited (3.0-9.5 kg ha–1yr–1 and the Centonara stream water was found to be unpolluted, with a nitrate concentration always below the EU limit for drinking water. The similar magnitude of total N inputs and outputs indicated that the crop management, especially the crop rotation and the N fertilization, in the Centonara watershed has reached a good level of

Combined effects of nitrogen to phosphorus ratios and nitrogen speciation on cyanobacterial metabolite concentrations in eutrophic Midwestern USA reservoirs.

NARCIS (Netherlands)

Harris, T.D.; Smith, V.H.; Graham, J.L.; Van de Waal, D.B.; Tedesco, L.P.; Clercin, N.

2016-01-01

Recent studies have shown that the total nitrogen to total phosphorus (TN:TP) ratio and nitrogen oxidation state may have substantial effects on secondary metabolite (e.g., microcystins) production in cyanobacteria. We investigated the relationship between the water column TN:TP ratio and the

Apple wine processing with different nitrogen contents

Directory of Open Access Journals (Sweden)

Aline Alberti

2011-06-01

Full Text Available The aim of this work was to evaluate the nitrogen content in different varieties of apple musts and to study the effect of different nitrogen concentrations in apple wine fermentation. The average total nitrogen content in 51 different apples juices was 155.81 mg/L, with 86.28 % of the values above 100 mg/L. The apple must with 59.0, 122.0 and 163.0 mg/L of total nitrogen content showed the maximum population of 2.05x 10(7; 4.42 x 10(7 and 8.66 x 10(7 cell/mL, respectively. Therefore, the maximum fermentation rates were dependent on the initial nitrogen level, corresponding to 1.4, 5.1 and 9.2 g/L.day, respectively. The nitrogen content in the apple musts was an important factor of growth and fermentation velocity.

Total recovery of nitrogen and phosphorus from three wetland plants by fast pyrolysis technology.

Science.gov (United States)

Liu, Wu-Jun; Zeng, Fan-Xin; Jiang, Hong; Yu, Han-Qing

2011-02-01

Fast pyrolysis of three wetland plants (Alligator weed, Oenanthe javanica and Typha angustifolia) in a vertical drop fixed bed reactor was investigated in this study. The experiments were carried out at different pyrolysis temperatures, and the maximum bio-oil yields achieved were 42.3%, 40.2% and 43.6% for Alligator weed, Oenanthe javanica and Typha angustifolia, respectively. The elemental composition of the bio-oil and char were analyzed, and the results show that a low temperature was appropriate for the nitrogen and phosphorus enrichment in char. GC-MS analysis shows that nitrogenous compounds, phenols and oxygenates were the main categories in the bio-oil. A series of leaching tests were carried out to examine the recovery of the nitrogen and phosphorus in the char, and the results indicate that significant fractions of nitrogen and phosphorus could be recovered by leaching process. Copyright © 2010 Elsevier Ltd. All rights reserved.

Methyl mercury, but not inorganic mercury, associated with higher blood pressure during pregnancy.

Science.gov (United States)

Wells, Ellen M; Herbstman, Julie B; Lin, Yu Hong; Hibbeln, Joseph R; Halden, Rolf U; Witter, Frank R; Goldman, Lynn R

2017-04-01

Prior studies addressing associations between mercury and blood pressure have produced inconsistent findings; some of this may result from measuring total instead of speciated mercury. This cross-sectional study of 263 pregnant women assessed total mercury, speciated mercury, selenium, and n-3 polyunsaturated fatty acids in umbilical cord blood and blood pressure during labor and delivery. Models with a) total mercury or b) methyl and inorganic mercury were evaluated. Regression models adjusted for maternal age, race/ethnicity, prepregnancy body mass index, neighborhood income, parity, smoking, n-3 fatty acids and selenium. Geometric mean total, methyl, and inorganic mercury concentrations were 1.40µg/L (95% confidence interval: 1.29, 1.52); 0.95µg/L (0.84, 1.07); and 0.13µg/L (0.10, 0.17), respectively. Elevated systolic BP, diastolic BP, and pulse pressure were found, respectively, in 11.4%, 6.8%, and 19.8% of mothers. In adjusted multivariable models, a one-tertile increase of methyl mercury was associated with 2.83mmHg (0.17, 5.50) higher systolic blood pressure and 2.99mmHg (0.91, 5.08) higher pulse pressure. In the same models, an increase of one tertile of inorganic mercury was associated with -1.18mmHg (-3.72, 1.35) lower systolic blood pressure and -2.51mmHg (-4.49, -0.53) lower pulse pressure. No associations were observed with diastolic pressure. There was a non-significant trend of higher total mercury with higher systolic blood pressure. We observed a significant association of higher methyl mercury with higher systolic and pulse pressure, yet higher inorganic mercury was significantly associated with lower pulse pressure. These results should be confirmed with larger, longitudinal studies. Copyright © 2017 Elsevier Inc. All rights reserved.

Determination of the atomic C/N assimilation ratio values of a pure culture of dunaliella and samples from rivers in Terengganu using the sup 14 C tracer method

International Nuclear Information System (INIS)

Lokman bin Shamsudin

1990-01-01

The C/N assimilation ratio has been defined by Chan and Raine as the ratio of carbon assimilated by a given algal population to that of the total inorganic nitrogen assimilated. The apparent carbon to nitrogen assimilation ratio for Dunaliella (pure algal culture) as well as subsurface water taken from some rivers in Terengganu was mainly attributed to the assimilation of the type of inorganic nitrogen, namely ammonium or nitrate found in the medium. The high C/N value for the various water samples was mainly attributed to the assimilation of ammonium nitrogen available in large amount in the tropical aquatic environment. The ammonium-nitrogen contents exceeds that of nitrate contents at the two stations

Dryland Winter Wheat Yield, Grain Protein, and Soil Nitrogen Responses to Fertilizer and Biosolids Applications

Directory of Open Access Journals (Sweden)

Richard T. Koenig

2011-01-01

Full Text Available Applications of biosolids were compared to inorganic nitrogen (N fertilizer for two years at three locations in eastern Washington State, USA, with diverse rainfall and soft white, hard red, and hard white winter wheat (Triticum aestivum L. cultivars. High rates of inorganic N tended to reduce yields, while grain protein responses to N rate were positive and linear for all wheat market classes. Biosolids produced 0 to 1400 kg ha−1 (0 to 47% higher grain yields than inorganic N. Wheat may have responded positively to nutrients other than N in the biosolids or to a metered N supply that limited vegetative growth and the potential for moisture stress-induced reductions in grain yield in these dryland production systems. Grain protein content with biosolids was either equal to or below grain protein with inorganic N, likely due to dilution of grain N from the higher yields achieved with biosolids. Results indicate the potential to improve dryland winter wheat yields with biosolids compared to inorganic N alone, but perhaps not to increase grain protein concentration of hard wheat when biosolids are applied immediately before planting.

Prescribed fire, soil inorganic nitrogen dynamics, and plant responses in a semiarid grassland

Science.gov (United States)

David J. Augustine; Paul Brewer; Dana M. Blumenthal; Justin D. Derner; Joseph C. von Fischer

2014-01-01

In arid and semiarid ecosystems, fire can potentially affect ecosystem dynamics through changes in soil moisture, temperature, and nitrogen cycling, as well as through direct effects on plant meristem mortality. We examined effects of annual and triennial prescribed fires conducted in early spring on soil moisture, temperature, and N, plant growth, and plant N content...

{sup 15}N-labeled nitrogen from green manure and ammonium sulfate utilization by the sugarcane ratoon

Energy Technology Data Exchange (ETDEWEB)

Ambrosano, Edmilson Jose; Rossi, Fabricio, E-mail: ambrosano@apta.sp.gov.b [Agencia Paulista de Tecnologia dos Agronegocios (APTA), Piracicapa, SP (Brazil). Polo Rigional Centro Sul; Trivelin, Paulo Cesar Ocheuze [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil). Lab. de Isotopos Estaveis; Cantarella, Heitor [Agencia Paulista de Tecnologia dos Agronegocios (APTA/IAC), Campinas, SP (Brazil). Instituto Agronomico de Campinas. Centro de Solos e Recursos Agroambientais; Ambrosano, Glaucia Maria Bovi [Universidade de Campinas (UNICAMP/FOP), Piracicaba, SP (Brazil). Fac. de Odontologia de Piracicaba. Dept. de Odontologia Social, Bioestatistica; Schammass, Eliana Aparecida [Agencia Paulista de Tecnologia dos Agronegocios (APTA/IZ), Nova Odessa, SP (Brazil). Instituto de Zootecnia; Muraoka, Takashi [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil). Lab. de Fertilidade do solo

2011-05-15

Legumes as green manure are alternative sources of nitrogen (N) for crops and can supplement or even replace mineral nitrogen fertilization due to their potential for biological nitrogen fixation (BNF). The utilization of nitrogen by sugarcane (Saccharum spp.) fertilized with sunn hemp (Crotalaria juncea L.) and ammonium sulfate (AS) was evaluated using the {sup 15}N tracer technique. N was added at the rate of 196 and 70 kg ha{sup -1} as {sup 15}N-labeled sunn hemp green manure (SH) and as ammonium sulfate (AS), respectively. Treatments were: (I) Control; (II) AS{sup 15}N; (III) SH{sup 15}N + AS; (IV) SH{sup 15}N; and (V) AS{sup 15}N + SH. Sugarcane was cultivated for five years and was harvested three times. {sup 15}N recovery was evaluated in the two first harvests. In the sum of the three harvests, the highest stalk yields were obtained with a combination of green manure and inorganic N fertilizer; however, in the second cutting the yields were higher where SH was used than in plots with AS. The recovery of N by the first two consecutive harvests accounted for 19 to 21% of the N applied as leguminous green manure and 46 to 49% of the N applied as AS. The amounts of inorganic N, derived from both N sources, present in the 0-0.4 m layer of soil in the first season after N application and were below 1 kg ha{sup -1}. (author)

Selection of effective macroalgal species and tracing nitrogen sources on the different part of Yantai coast, China indicated by macroalgal δ15N values

International Nuclear Information System (INIS)

Wang, Yujue; Liu, Dongyan; Richard, Pierre; Di, Baoping

2016-01-01

To determine the dominant nitrogen sources and select effective macroalgal species for monitoring eutrophication along the Yantai coast, the total carbon (TOC), total nitrogen (TN) and nitrogen stable isotope ratio (δ 15 N) in macroalgal tissue were analyzed in conjunction with environmental variables in seawater along the Yantai coastline. The ranges of macroalgal tissue δ 15 N values together with dissolved inorganic nitrogen (DIN) composition indicated that except for the atmospheric deposition, there were three dominant types of nitrogen sources along the Yantai coast, with the agricultural fertilizer usage and factorial wastewater input at the S1 (Zhifu Island coast), the sewage discharge at S2 (the Moon Bay coast), the sewage discharge together with aquaculture impacts at S3 (Fisherman Wharf coast) and S4 (the Horse Island coast). Macroalgal growth were not limited by DIN but limited by P at S2, S3 and S4. Macroalgal species suitable or not for DIN source tracing along the Yantai coast were discussed. For sites with low DIN concentration, many species of three phyla could be used for DIN sources tracing with Laurencia okamurai, Gloiopeltis furcata and Ulva pertusa being ideal species. For site with high DIN concentration, however, species of Rhodophyta were not suitable and only Scytosiphon lomentaria and Monostroma nitidium were chosen. - Highlights: • Yantai coast was affected by three types of DIN sources. • Macroalgal species suitable or not for DIN source tracing were suggested; • TN and δ 15 N were affected by nutrient concentrations and the metabolic factors. • P instead of N limited the tissue N uptake in low nutrient concentration sites.

Inorganic arsenic and iron(II) distributions in sediment porewaters investigated by a combined DGTcolourimetric DET technique

DEFF Research Database (Denmark)

Bennett, William W.; Teasdale, Peter R.; Welsh, David T.

2012-01-01

A new approach for investigating the biogeochemistry of inorganic arsenic and iron(II) in freshwater, estuarine and marine sediments is reported. The recently developed Metsorb diffusive gradients in thin films (DGT) technique for the measurement of total inorganic arsenic and the colourimetric d...... highly representative assessment of the biogeochemical status of arsenic and iron in a variety of natural sediments, including groundwater sediments where mobilised arsenic is responsible for significant human health risks.......A new approach for investigating the biogeochemistry of inorganic arsenic and iron(II) in freshwater, estuarine and marine sediments is reported. The recently developed Metsorb diffusive gradients in thin films (DGT) technique for the measurement of total inorganic arsenic and the colourimetric...... diffusive equilibration in thin films (DET) technique for the measurement of iron(II), were utilised in combination to determine co-located depth profiles of both solutes in sediment porewaters. DGT-measured porewater arsenic concentrations were typically less than 40nM, whereas iron(II) concentrations...

Comparison of five organic wastes regarding their behaviour during composting: Part 2, nitrogen dynamic

International Nuclear Information System (INIS)

Guardia, A. de; Mallard, P.; Teglia, C.; Marin, A.; Le Pape, C.; Launay, M.; Benoist, J.C.; Petiot, C.

2010-01-01

This paper aimed to compare household waste, separated pig solids, food waste, pig slaughterhouse sludge and green algae regarding processes ruling nitrogen dynamic during composting. For each waste, three composting simulations were performed in parallel in three similar reactors (300 L), each one under a constant aeration rate. The aeration flows applied were comprised between 100 and 1100 L/h. The initial waste and the compost were characterized through the measurements of their contents in dry matter, total carbon, Kjeldahl and total ammoniacal nitrogen, nitrite and nitrate. Kjeldahl and total ammoniacal nitrogen and nitrite and nitrate were measured in leachates and in condensates too. Ammonia and nitrous oxide emissions were monitored in continue. The cumulated emissions in ammonia and in nitrous oxide were given for each waste and at each aeration rate. The paper focused on process of ammonification and on transformations and transfer of total ammoniacal nitrogen. The parameters of nitrous oxide emissions were not investigated. The removal rate of total Kjeldahl nitrogen was shown being closely tied to the ammonification rate. Ammonification was modelled thanks to the calculation of the ratio of biodegradable carbon to organic nitrogen content of the biodegradable fraction. The wastes were shown to differ significantly regarding their ammonification ability. Nitrogen balances were calculated by subtracting nitrogen losses from nitrogen removed from material. Defaults in nitrogen balances were assumed to correspond to conversion of nitrate even nitrite into molecular nitrogen and then to the previous conversion by nitrification of total ammoniacal nitrogen. The pool of total ammoniacal nitrogen, i.e. total ammoniacal nitrogen initially contained in waste plus total ammoniacal nitrogen released by ammonification, was calculated for each experiment. Then, this pool was used as the referring amount in the calculation of the rates of accumulation, stripping and

[Development and evaluation of fertilizers cemented and coated with organic-inorganic materials].

Science.gov (United States)

Xiao, Qiang; Wang, Jia-Chen; Zuo, Qiang; Zhang, Lin; Liu, Bao-Cun; Zhao, Tong-Ke; Zou, Guo-Yuan; Xu, Qiu-Ming

2010-01-01

Four kinds of organic-inorganic cementing and coating materials were prepared by a coating method using water as the solvent, and the corresponding cemented and coated fertilizers (B2, PS, F2, and F2F) were produced by disc pelletizer. The tests on the properties of these fertilizers showed that the granulation rate, compression strength, and film-forming rate were B2 > PS > F2 > F2F. Soil column leaching experiment showed that the curve of accumulated nitrogen-dissolving rate was the gentlest for B2. In 48 days, the accumulated nitrogen-dissolving rate was in the order of B2, 54.65% fertilizers had better effects on corn yield, among which, B2 was the best, with the corn yield and fertilizer use efficiency increased by 19.72% and 20.30%, respectively. The yield-increasing effect of other test fertilizers was in the order of PS > F2 > F2F.

Adjustment of growth and central metabolism to a mild but sustained nitrogen-limitation in Arabidopsis.

Science.gov (United States)

Tschoep, Hendrik; Gibon, Yves; Carillo, Petronia; Armengaud, Patrick; Szecowka, Marek; Nunes-Nesi, Adriano; Fernie, Alisdair R; Koehl, Karin; Stitt, Mark

2009-03-01

We have established a simple soil-based experimental system that allows a small and sustained restriction of growth of Arabidopsis by low nitrogen (N). Plants were grown in a large volume of a peat-vermiculite mix that contained very low levels of inorganic N. As a control, inorganic N was added in solid form to the peat-vermiculite mix, or plants were grown in conventional nutrient-rich solids. The low N growth regime led to a sustained 20% decrease of the relative growth rate over a period of 2 weeks, resulting in a two- to threefold decrease in biomass in 35- to 40-day-old plants. Plants in the low N regime contained lower levels of nitrate, lower nitrate reductase activity, lower levels of malate, fumarate and other organic acids and slightly higher levels of starch, as expected from published studies of N-limited plants. However, their rosette protein content was unaltered, and total and many individual amino acid levels increased compared with N-replete plants. This metabolic phenotype reveals that Arabidopsis responds adaptively to low N by decreasing the rate of growth, while maintaining the overall protein content, and maintaining or even increasing the levels of many amino acids.

Specific and total N-nitrosamines formation potentials of nitrogenous micropollutants during chloramination.

Science.gov (United States)

Piazzoli, Andrea; Breider, Florian; Aquillon, Caroline Gachet; Antonelli, Manuela; von Gunten, Urs

2018-05-15

N-nitrosamines are a group of potent human carcinogens that can be formed during oxidative treatment of drinking water and wastewater. Many tertiary and quaternary amines present in consumer products (e.g., pharmaceuticals, personal care and household products) are known to be N-nitrosodimethylamine (NDMA) precursors during chloramination, but the formation of other N-nitrosamines has been rarely studied. This study investigates the specific and total N-nitrosamine (TONO) formation potential (FP) of various precursors from nitrogen-containing micropollutants (chlorhexidine, metformin, benzalkonium chloride and cetyltrimethylammonium chloride) and tertiary and quaternary model amines (trimethyl amine, N,N-dimethylbutyl amine, N,N-dimethylbenzyl amine and tetramethyl ammonium). All the studied nitrogenous micropollutants displayed quantifiable TONO FP, with molar yields in the range 0.04-11.92%. However, the observed TONO pools constituted mostly of uncharacterized species, not included in US-EPA 8270 N-nitrosamines standard mix. Only the quaternary ammonium compound benzalkonium chloride showed quantifiable NDMA FP (0.56% molar yield), however, explaining only a minor fraction of the observed TONO FP. The studied model amines showed molar NDMA yields from 0.10% (trimethyl amine) to 5.05% (N,N-dimethylbenzyl amine), very similar to the molar TONO yields. The comparison of the FPs of micropollutants and model compounds showed that the presence of electron donating functional groups (such as a benzyl group) in tertiary and quaternary amine precursors leads to a higher formation of NDMA and uncharacterized N-nitrosamines, respectively. LC-qTOF screening of a list of proposed N-nitrosamine structures has enabled to identify a novel N-nitrosamine (N-nitroso-N-methyldodecylamine) from the chloramination of benzalkonium chloride. This finding supports the hypothesis that different functional groups in quaternary amines can act as leaving groups during chloramination and

[Nitrogen Fraction Distributions and Impacts on Soil Nitrogen Mineralization in Different Vegetation Restorations of Karst Rocky Desertification].

Science.gov (United States)

Hu, Ning; Ma, Zhi-min; Lan, Jia-cheng; Wu, Yu-chun; Chen, Gao-qi; Fu, Wa-li; Wen, Zhi-lin; Wang, Wen-jing

2015-09-01

In order to illuminate the impact on soil nitrogen accumulation and supply in karst rocky desertification area, the distribution characteristics of soil nitrogen pool for each class of soil aggregates and the relationship between aggregates nitrogen pool and soil nitrogen mineralization were analyzed in this study. The results showed that the content of total nitrogen, light fraction nitrogen, available nitrogen and mineral nitrogen in soil aggregates had an increasing tendency along with the descending of aggregate-size, and the highest content was occurred in 5mm and 2-5 mm classes, and the others were the smallest. With the positive vegetation succession, the weight percentage of > 5 mm aggregate-size classes was improved and the nitrogen storage of macro-aggregates also was increased. Accordingly, the capacity of soil supply mineral nitrogen and storage organic nitrogen were intensified.

Nitrogen fixation by free-living microorganisms in tropical rice soils using labelled fertilizer. Part of a coordinated programme on isotope techniques in studies of biological nitrogen fixation for the dual purpose of increasing crop production and decreasing nitrogen fertilizer use to conserve the environment

International Nuclear Information System (INIS)

Rao, V.R.

1981-11-01

Both acetylene-reduction and 15 N techniques were used to study heterotrophic N fixation in the rhizosphere of rice plants. Soils subjected to flooding in 4 soil types in both greenhouse and the field were found to stimulate greater heterotrophic nitrogen fixation than moist soils. The addition of organic materials, in particular, cellulose and rice straw, in general, enhanced nitrogen fixed by heterotrophic organisms living in the rhizosphere of rice plants. The highest amount of N fixed was 38 kg N/ha, and was obtained in a flooded lateritic soil to which had been added cellulose. Heterotrophic nitrogen fixation was influenced by soil type. In this study, the lowest value for fixed N was recorded in an acid sulphate soil of low pH. The addition of increasing amounts of inorganic nitrogen fertilizer in the form of ammonium sulphate suppressed rhizospheric nitrogen fixation in all soils, but the extent of suppression differed in the different soils. Benomyl fungicide and methyl carbamate insecticide had a stimulatory effect on heterotrophic nitrogen fixation in soils under rice roots. Different rice cultivars stimulated strains of Azospirillum to varying extent, and thus did not fix nitrogen to the same extent. It is thus possible that varieties of rice could be selected on the basis of their ability to support non-symbiotic N fixation in their rhizosphere

The influence of nitrogen sources on the alpha-amylase productivity of Aspergillus oryzae in continuous cultures

DEFF Research Database (Denmark)

Pedersen, Henrik; Nielsen, Jens

2000-01-01

The influence of the nitrogen source on the cc-amylase productivity of Aspergillus oryzae was quantified in continuous cultivations. Both inorganic and complex nitrogen sources were investigated and glucose was used as the carbon and energy sources. For production of alpha-amylase, nitrate...... in the cc-amylase productivity. The higher alpha-amylase productivity during growth on casein hydrolysate was not caused by increased transcription of the alpha-amylase genes but was caused by a faster secretion of alpha-amylase or by a lower binding of alpha-amylase to the biomass....

Biochar Decelerates Soil Organic Nitrogen Cycling but Stimulates Soil Nitrification in a Temperate Arable Field Trial

Science.gov (United States)

Prommer, Judith; Wanek, Wolfgang; Hofhansl, Florian; Trojan, Daniela; Offre, Pierre; Urich, Tim; Schleper, Christa; Sassmann, Stefan; Kitzler, Barbara; Soja, Gerhard; Hood-Nowotny, Rebecca Clare

2014-01-01

Biochar production and subsequent soil incorporation could provide carbon farming solutions to global climate change and escalating food demand. There is evidence that biochar amendment causes fundamental changes in soil nutrient cycles, often resulting in marked increases in crop production, particularly in acidic and in infertile soils with low soil organic matter contents, although comparable outcomes in temperate soils are variable. We offer insight into the mechanisms underlying these findings by focusing attention on the soil nitrogen (N) cycle, specifically on hitherto unmeasured processes of organic N cycling in arable soils. We here investigated the impacts of biochar addition on soil organic and inorganic N pools and on gross transformation rates of both pools in a biochar field trial on arable land (Chernozem) in Traismauer, Lower Austria. We found that biochar increased total soil organic carbon but decreased the extractable organic C pool and soil nitrate. While gross rates of organic N transformation processes were reduced by 50–80%, gross N mineralization of organic N was not affected. In contrast, biochar promoted soil ammonia-oxidizer populations (bacterial and archaeal nitrifiers) and accelerated gross nitrification rates more than two-fold. Our findings indicate a de-coupling of the soil organic and inorganic N cycles, with a build-up of organic N, and deceleration of inorganic N release from this pool. The results therefore suggest that addition of inorganic fertilizer-N in combination with biochar could compensate for the reduction in organic N mineralization, with plants and microbes drawing on fertilizer-N for growth, in turn fuelling the belowground build-up of organic N. We conclude that combined addition of biochar with fertilizer-N may increase soil organic N in turn enhancing soil carbon sequestration and thereby could play a fundamental role in future soil management strategies. PMID:24497947

Biochar decelerates soil organic nitrogen cycling but stimulates soil nitrification in a temperate arable field trial.

Directory of Open Access Journals (Sweden)

Judith Prommer

Full Text Available Biochar production and subsequent soil incorporation could provide carbon farming solutions to global climate change and escalating food demand. There is evidence that biochar amendment causes fundamental changes in soil nutrient cycles, often resulting in marked increases in crop production, particularly in acidic and in infertile soils with low soil organic matter contents, although comparable outcomes in temperate soils are variable. We offer insight into the mechanisms underlying these findings by focusing attention on the soil nitrogen (N cycle, specifically on hitherto unmeasured processes of organic N cycling in arable soils. We here investigated the impacts of biochar addition on soil organic and inorganic N pools and on gross transformation rates of both pools in a biochar field trial on arable land (Chernozem in Traismauer, Lower Austria. We found that biochar increased total soil organic carbon but decreased the extractable organic C pool and soil nitrate. While gross rates of organic N transformation processes were reduced by 50-80%, gross N mineralization of organic N was not affected. In contrast, biochar promoted soil ammonia-oxidizer populations (bacterial and archaeal nitrifiers and accelerated gross nitrification rates more than two-fold. Our findings indicate a de-coupling of the soil organic and inorganic N cycles, with a build-up of organic N, and deceleration of inorganic N release from this pool. The results therefore suggest that addition of inorganic fertilizer-N in combination with biochar could compensate for the reduction in organic N mineralization, with plants and microbes drawing on fertilizer-N for growth, in turn fuelling the belowground build-up of organic N. We conclude that combined addition of biochar with fertilizer-N may increase soil organic N in turn enhancing soil carbon sequestration and thereby could play a fundamental role in future soil management strategies.

Biochar decelerates soil organic nitrogen cycling but stimulates soil nitrification in a temperate arable field trial.

Science.gov (United States)

Prommer, Judith; Wanek, Wolfgang; Hofhansl, Florian; Trojan, Daniela; Offre, Pierre; Urich, Tim; Schleper, Christa; Sassmann, Stefan; Kitzler, Barbara; Soja, Gerhard; Hood-Nowotny, Rebecca Clare

2014-01-01

Biochar production and subsequent soil incorporation could provide carbon farming solutions to global climate change and escalating food demand. There is evidence that biochar amendment causes fundamental changes in soil nutrient cycles, often resulting in marked increases in crop production, particularly in acidic and in infertile soils with low soil organic matter contents, although comparable outcomes in temperate soils are variable. We offer insight into the mechanisms underlying these findings by focusing attention on the soil nitrogen (N) cycle, specifically on hitherto unmeasured processes of organic N cycling in arable soils. We here investigated the impacts of biochar addition on soil organic and inorganic N pools and on gross transformation rates of both pools in a biochar field trial on arable land (Chernozem) in Traismauer, Lower Austria. We found that biochar increased total soil organic carbon but decreased the extractable organic C pool and soil nitrate. While gross rates of organic N transformation processes were reduced by 50-80%, gross N mineralization of organic N was not affected. In contrast, biochar promoted soil ammonia-oxidizer populations (bacterial and archaeal nitrifiers) and accelerated gross nitrification rates more than two-fold. Our findings indicate a de-coupling of the soil organic and inorganic N cycles, with a build-up of organic N, and deceleration of inorganic N release from this pool. The results therefore suggest that addition of inorganic fertilizer-N in combination with biochar could compensate for the reduction in organic N mineralization, with plants and microbes drawing on fertilizer-N for growth, in turn fuelling the belowground build-up of organic N. We conclude that combined addition of biochar with fertilizer-N may increase soil organic N in turn enhancing soil carbon sequestration and thereby could play a fundamental role in future soil management strategies.

Cultivating Chlorella vulgaris and Scenedesmus quadricauda microalgae to degrade inorganic compounds and pesticides in water.

Science.gov (United States)

Baglieri, Andrea; Sidella, Sarah; Barone, Valeria; Fragalà, Ferdinando; Silkina, Alla; Nègre, Michèle; Gennari, Mara

2016-09-01

This work evaluates the possibility of cultivating Scenedesmus quadricauda and Chlorella vulgaris microalgae in wastewater from the hydroponic cultivation of tomatoes with the aim of purifying the water. S. quadricauda and C. vulgaris were also used in purification tests carried out on water contaminated by the following active ingredients: metalaxyl, pyrimethanil, fenhexamid, iprodione, and triclopyr. Fifty-six days after the inoculum was placed, a reduction was found in the concentration of nitric nitrogen, ammonia nitrogen, and soluble and total phosphorus. The decrease was 99, 83, 94, and 94 %, respectively, for C. vulgaris and 99, 5, 88, and 89 %, respectively, for S. quadricauda. When the microalgae were present, all the agrochemicals tested were removed more quickly from the water than from the sterile control (BG11). The increase in the rate of degradation was in the order metalaxyl > fenhexamid > iprodione > triclopyr > pyrimethanil. It was demonstrated that there was a real degradation of fenhexamid, metalaxyl, triclopyr, and iprodione, while in the case of pyrimethanil, the active ingredient removed from the substrate was absorbed onto the cells of the microalgae. It was also found that the agrochemicals used in the tests had no significant effect on the growth of the two microalgae. The experiment highlighted the possibility of using cultivations of C. vulgaris and S. quadricauda as purification systems for agricultural wastewater which contains eutrophic inorganic compounds such as nitrates and phosphates and also different types of pesticides.

Dissolution and Release of Gaseous Nitrogen (N2, N2O) in the Source Region of the Yellow River

Science.gov (United States)

Zhang, L.; Xia, X.; Wang, J.

2017-12-01

Nitrogen is an important biogenic element. The migration and transformation of nitrogen in rivers is an important process affecting global nitrogen cycling and greenhouse gas emissions. However, there is a lack of research on nitrogen removal and greenhouse gas emission characteristics of high altitude rivers. In this work, the spatial and temporal variations of dissolved nitrogen (N2 and N2O) concentrations, saturation, and release flux as well as their responses to environmental factors were studied in the Yellow River source area, a typical high altitude river. The results showed that the dissolved concentrations of N2 and N2O in the rivers were 8.24-137.75 μmol.L-1 and 2.57-31.94 nmol.L-1, respectively. N2 and N2O saturation were greater than 100% for all the sampling sites, indicating that the river is a release source for atmosphere N2 and N2O. Correspondingly, the fluxes of N2 and N2O from river water to atmosphere were 24.12-1606.57 mmol (m2.d) -1 and 12.96-276.81 μmol (m2.d) -1, respectively. Generally, the dissolution concentration and release flux of N2 and N2O in July were larger than that in May. The concentrations of N2 and N2O in river water were related to the environmental factors, and the dissolved concentration of N2 in the surface water was significantly positively correlated with water temperature, NH4+-N and total inorganic nitrogen (DIN) (p<0.01). The dissolved concentration of N2O was significantly positively correlated with the content of suspended particulates, DO, and DIN (p<0.01). Thus, DIN is a key factor in the process of N2 and N2O formation. This study can help to understand the nitrogen cycling in high-altitude rivers and provide basic data for a comprehensive assessment of global river nitrogen loss. Key Words: Source Region of the Yellow River; Gaseous Nitrogen; Nitrogen loss; High altitude river

A doubling of microphytobenthos biomass coincides with a tenfold increase in denitrifier and total bacterial abundances in intertidal sediments of a temperate estuary.

Directory of Open Access Journals (Sweden)

Helen Decleyre

Full Text Available Surface sediments are important systems for the removal of anthropogenically derived inorganic nitrogen in estuaries. They are often characterized by the presence of a microphytobenthos (MPB biofilm, which can impact bacterial communities in underlying sediments for example by secretion of extracellular polymeric substances (EPS and competition for nutrients (including nitrogen. Pyrosequencing and qPCR was performed on two intertidal surface sediments of the Westerschelde estuary characterized by a two-fold difference in MPB biomass but no difference in MPB composition. Doubling of MPB biomass was accompanied by a disproportionately (ten-fold increase in total bacterial abundances while, unexpectedly, no difference in general community structure was observed, despite significantly lower bacterial richness and distinct community membership, mostly for non-abundant taxa. Denitrifier abundances corresponded likewise while community structure, both for nirS and nirK denitrifiers, remained unchanged, suggesting that competition with diatoms for nitrate is negligible at concentrations in the investigated sediments (appr. 1 mg/l NO3-. This study indicates that MPB biomass increase has a general, significantly positive effect on total bacterial and denitrifier abundances, with stimulation or inhibition of specific bacterial groups that however do not result in a re-structured community.

The relative importance of exogenous and substrate-derived nitrogen for microbial growth during leaf decomposition

Science.gov (United States)

B.M. Cheever; J. R. Webster; E. E. Bilger; S. A. Thomas

2013-01-01

Heterotrophic microbes colonizing detritus obtain nitrogen (N) for growth by assimilating N from their substrate or immobilizing exogenous inorganic N. Microbial use of these two pools has different implications for N cycling and organic matter decomposition in the face of the global increase in biologically available N. We used sugar maple leaves labeled with

Automated system for on-line determination of dimethylarsinic and inorganic arsenic by hydride generation-atomic fluorescence spectrometry

Energy Technology Data Exchange (ETDEWEB)

Chaparro, L.L.; Leal, L.O. [Renewable Energy and Environmental Protection Department, Advanced Materials Research Center (CIMAV), Chihuahua, Chihuahua (Mexico); Ferrer, L.; Cerda, V. [University of the Balearic Islands, Department of Chemistry, Palma de Mallorca (Spain)

2012-09-15

A multisyringe flow-injection approach has been coupled to hydride generation-atomic fluorescence spectrometry (HG-AFS) with UV photo-oxidation for dimethylarsinic (DMA), inorganic As and total As determination, depending on the pre-treatment given to the sample (extraction or digestion). The implementation of a UV lamp allows on-line photo-oxidation of DMA and the following arsenic detection, whereas a bypass leads the flow directly to the HG-AFS system, performing inorganic arsenic determination. DMA concentration is calculated by the difference of total inorganic arsenic and measurement of the photo-oxidation step. The detection limits for DMA and inorganic arsenic were 0.09 and 0.47 {mu}g L{sup -1}, respectively. The repeatability values accomplished were of 2.4 and 1.8 %, whereas the injection frequencies were 24 and 28 injections per hour for DMA and inorganic arsenic, respectively. This method was validated by means of a solid reference material BCR-627 (muscle of tuna) with good agreement with the certified values. Satisfactory results for DMA and inorganic arsenic determination were obtained in several water matrices. The proposed method offers several advantages, such as increasing the sampling frequency, low detection limits and decreasing reagents and sample consumption, which leads to lower waste generation. (orig.)

Micronutrients as Impurities of Inorganic Fertilizers Marketed in Saudi Arabia

Directory of Open Access Journals (Sweden)

A.S. Modaihsh

2000-06-01

Full Text Available Inorganic fertilizers with major nutrients are likely to be contaminated with some micronutrients. Fertilizers, utilized in Saudi Arabia, were analyzed for their total and water-soluble content of Fe, Zn, Mn and Cu. They represented three categories namely: phosphatic, solid multiple nutrient fertilizers (SMNF and water-soluble multiple nutrient fertilizers (WSMF. Total iron content in examined fertilizers was higher in phosphatic fertilizers and lower in WSMF. Nevertheless, only a very small portion of the total iron content is likely to be available to plants. It was estimated, on the basis of total content, that almost 2 g of iron would be applied to soil for each added kg of phosphatic fertilizer. The highest total content of Zn was recorded for phosphatic fertilizers. The data suggested that less than half kg of Zn would be accumulated in soil if 500 kg of phosphatic fertilizers were applied in one year. This value however, fell dramatically, to one fourth of the value, when only the available forms of Zn were considered. Fertilizer content of manganese and copper were lower than both Fe and Zn. Micronutrient impurities present in inorganic fertilizers might not have an immediate influence on plant nutrition due to their lower solubility.

Distribution of Coral Reef and Seagrass Ecosystems’s Inorganic Carbon in the Waters of Beras Basah Bontang, East Kalimantan

Directory of Open Access Journals (Sweden)

Irwan Ramadhan Ritonga

2013-06-01

Full Text Available Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 Inorganic carbon is closely related to the calcification process (CaCO3, which is the main constituent of coral reefs or microorganisms that exist in the oceans such as foraminifera and cocolitoporit. Inorganic carbon is also closely linked to the chemical processes that occur when carbon dioxide gas (CO2 dissolved in water. The research of inorganic carbon in the waters of Beras Basah was carried out in January, February and March 2012. The purpose of this study was to understand the distribution and concentration of total inorganic carbon (CT in coral reef and seagrass ecosystems as well as the correlation of Beras Basah. The results showed that the concentration of total inorganic carbon (CT in January average 1166.503 μmol/kgSW, February average 1115.599 μmol/kgSW, and then in March the average 987.443 μmol/kgSW. Distribution patterns of total inorganic carbon (CT is vectoral, where in January, the concentration of total inorganic carbon (CT was highest in the Southeast region, was in February in the South and Southeast, while in March shifted to North region of Beras Basah Island. The concentration difference is thought to be influenced by pH and the seasons, tides, biochemical processes, and biological activity. Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 Doi: 10.12777/ijse.5.1.1-5 [How to cite this article: Ritonga, I.R., Supriharyono, and Henderarto, B. (2013. Distribution of Coral Reef and Seagrass Ecosystems’s Inorganic Carbon in the Waters of Beras Basah Bontang, East Kalimantan. International Journal of Science and Engineering, 5(1,1-6. Doi: 10.12777/ijse.5.1.1-5]  Selection of effective macroalgal species and tracing nitrogen sources on the different part of Yantai coast, China indicated by macroalgal δ{sup 15}N values

Energy Technology Data Exchange (ETDEWEB)

Wang, Yujue [Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003 (China); Liu, Dongyan, E-mail: dyliu@yic.ac.cn [Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003 (China); Richard, Pierre [Littoral, Environnement et Sociétés, UMR 7266 CNRS-Université de La Rochelle, 2 rue Olympe de Gouges, 17000 La Rochelle (France); Di, Baoping [Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003 (China)

2016-01-15

To determine the dominant nitrogen sources and select effective macroalgal species for monitoring eutrophication along the Yantai coast, the total carbon (TOC), total nitrogen (TN) and nitrogen stable isotope ratio (δ{sup 15}N) in macroalgal tissue were analyzed in conjunction with environmental variables in seawater along the Yantai coastline. The ranges of macroalgal tissue δ{sup 15}N values together with dissolved inorganic nitrogen (DIN) composition indicated that except for the atmospheric deposition, there were three dominant types of nitrogen sources along the Yantai coast, with the agricultural fertilizer usage and factorial wastewater input at the S1 (Zhifu Island coast), the sewage discharge at S2 (the Moon Bay coast), the sewage discharge together with aquaculture impacts at S3 (Fisherman Wharf coast) and S4 (the Horse Island coast). Macroalgal growth were not limited by DIN but limited by P at S2, S3 and S4. Macroalgal species suitable or not for DIN source tracing along the Yantai coast were discussed. For sites with low DIN concentration, many species of three phyla could be used for DIN sources tracing with Laurencia okamurai, Gloiopeltis furcata and Ulva pertusa being ideal species. For site with high DIN concentration, however, species of Rhodophyta were not suitable and only Scytosiphon lomentaria and Monostroma nitidium were chosen. - Highlights: • Yantai coast was affected by three types of DIN sources. • Macroalgal species suitable or not for DIN source tracing were suggested; • TN and δ{sup 15}N were affected by nutrient concentrations and the metabolic factors. • P instead of N limited the tissue N uptake in low nutrient concentration sites.

Increasing plant use of organic nitrogen with elevation is reflected in nitrogen uptake rates and ecosystem delta15N.

Science.gov (United States)

Averill, Colin; Finzi, Adrien

2011-04-01

It is hypothesized that decreasing mean annual temperature and rates of nitrogen (N) cycling causes plants to switch from inorganic to organic forms of N as the primary mode of N nutrition. To test this hypothesis, we conducted field experiments and collected natural-abundance delta15N signatures of foliage, soils, and ectomycorrhizal sporocarps along a steep elevation-climate gradient in the White Mountains, New Hampshire, USA. Here we show that with increasing elevation organic forms of N became the dominant source of N taken up by hardwood and coniferous tree species based on dual-labeled glycine uptake analysis, an important confirmation of an emerging theory for the biogeochemistry of the N cycle. Variation in natural abundance foliar delta15N with elevation was also consistent with increasing organic N uptake, though a simple, mass balance model demonstrated that the uptake of delta15N depleted inorganic N, rather than fractionation upon transfer of N from mycorrhizal fungi, best explains variations in foliar delta15N with elevation.

A simple tool for estimating throughfall nitrogen deposition in forests of western North America using lichens

Science.gov (United States)

Heather T. Root; Linda H. Geiser; Mark E. Fenn; Sarah Jovan; Martin A. Hutten; Suraj Ahuja; Karen Dillman; David Schirokauer; Shanti Berryman; Jill A. McMurray

2013-01-01

Anthropogenic nitrogen (N) deposition has had substantial impacts on forests of North America. Managers seek to monitor deposition to identify areas of concern and establish critical loads, which define the amount of deposition that can be tolerated by ecosystems without causing substantial harm. We present a new monitoring approach that estimates throughfall inorganic...

Inorganic liquid scintillator

International Nuclear Information System (INIS)

Pavlicek, Z.; Barta, C.; Jursova, L.

1986-01-01

An inorganic liquid scintillator is designed which contains 1 to 30 wt.% of an inorganic molecular compound as the basic active component; the compound contains a cation with an atomic number higher than 47 and a halogen anion. The basic inorganic component is dissolved in water or in an organic solvent in form of non-dissociated molecules or self-complexes in which the bond is preserved between the cation and anion components. The light yield from these scintillators ranges between 70 and 150% of the light yield of a standard organic scintillator based on toluene. They are advantageous in that that they allow to increase the water content in the sample to up to 100%. (M.D.)

Autotrophic and heterotrophic acquisition of carbon and nitrogen by a mixotrophic chrysophyte established through stable isotope analysis.

Science.gov (United States)

Terrado, Ramon; Pasulka, Alexis L; Lie, Alle A-Y; Orphan, Victoria J; Heidelberg, Karla B; Caron, David A

2017-09-01

Collectively, phagotrophic algae (mixotrophs) form a functional continuum of nutritional modes between autotrophy and heterotrophy, but the specific physiological benefits of mixotrophic nutrition differ among taxa. Ochromonas spp. are ubiquitous chrysophytes that exhibit high nutritional flexibility, although most species generally fall towards the heterotrophic end of the mixotrophy spectrum. We assessed the sources of carbon and nitrogen in Ochromonas sp. strain BG-1 growing mixotrophically via short-term stable isotope probing. An axenic culture was grown in the presence of either heat-killed bacteria enriched with 15 N and 13 C, or unlabeled heat-killed bacteria and labeled inorganic substrates ( 13 C-bicarbonate and 15 N-ammonium). The alga exhibited high growth rates (up to 2 divisions per day) only until heat-killed bacteria were depleted. NanoSIMS and bulk IRMS isotope analyses revealed that Ochromonas obtained 84-99% of its carbon and 88-95% of its nitrogen from consumed bacteria. The chrysophyte assimilated inorganic 13 C-carbon and 15 N-nitrogen when bacterial abundances were very low, but autotrophic (photosynthetic) activity was insufficient to support net population growth of the alga. Our use of nanoSIMS represents its first application towards the study of a mixotrophic alga, enabling a better understanding and quantitative assessment of carbon and nutrient acquisition by this species.

"Cold" Fixation: Reconciliation of Nitrogen Fixation Rates and Diazotroph Assemblages in the Arctic Ocean

Science.gov (United States)

Fong, A. A.; Waite, A.; Rost, B.; Richter, K. U.

2016-02-01

Measurements of biological nitrogen fixation are typically conducted in oligotrophic subtropical and tropical marine environments where concentrations of fixed inorganic nitrogen are low. To date, only a handful of nitrogen fixation studies have been conducted in high latitude marine environments, but further investigation is needed to resolve the distribution of cold ocean diazotrophic assemblages. Nitrogen fixation rates and nifH gene distributions were measured at seven stations from 5°E to 20°E, north of 81°N in the Arctic Ocean at the onset of summer 2015. Discrete water samples in ice-covered regions were collected from the sea surface to 200 m for 15N2-tracer additions and targeted nifH gene and transcript analyses. Previous work suggests that heterotrophic bacteria dominate diazotrophic communities in the Arctic Ocean. Therefore, additional nifH gene surveys of sinking particles were conducted to test for enrichment on organic matter-rich microenvironments. Together, these measurements aim to reconcile diazotrophic activity with microbial community composition, further elucidating how nitrogen fixers could impact current concepts in polar carbon and nutrient cycling.

Fish consumption and bioindicators of inorganic mercury exposure

International Nuclear Information System (INIS)

Sousa Passos, Carlos Jose; Mergler, Donna; Lemire, Melanie; Fillion, Myriam; Guimaraes, Jean Remy Davee

2007-01-01

Background: The direct and close relationship between fish consumption and blood and hair mercury (Hg) levels is well known, but the influence of fish consumption on inorganic mercury in blood (B-IHg) and in urine (U-Hg) is unclear. Objective: Examine the relationship between fish consumption, total, inorganic and organic blood Hg levels and urinary Hg concentration. Methods: A cross-sectional study was carried out on 171 persons from 7 riparian communities on the Tapajos River (Brazilian Amazon), with no history of inorganic Hg exposure from occupation or dental amalgams. During the rising water season in 2004, participants responded to a dietary survey, based on a seven-day recall of fish and fruit consumption frequency, and socio-demographic information was recorded. Blood and urine samples were collected. Total, organic and inorganic Hg in blood as well as U-Hg were determined by Atomic Absorption Spectrometry. Results: On average, participants consumed 7.4 fish meals/week and 8.8 fruits/week. Blood total Hg averaged 38.6 ± 21.7 μg/L, and the average percentage of B-IHg was 13.8%. Average organic Hg (MeHg) was 33.6 ± 19.4 μg/L, B-IHg was 5.0 ± 2.6 μg/L, while average U-Hg was 7.5 ± 6.9 μg/L, with 19.9% of participants presenting U-Hg levels above 10 μg/L. B-IHg was highly significantly related to the number of meals of carnivorous fish, but no relation was observed with non-carnivorous fish; it was negatively related to fruit consumption, increased with age, was higher among those who were born in the Tapajos region, and varied with community. U-Hg was also significantly related to carnivorous but not non-carnivorous fish consumption, showed a tendency towards a negative relation with fruit consumption, was higher among men compared to women and higher among those born in the region. U-Hg was strongly related to I-Hg, blood methyl Hg (B-MeHg) and blood total Hg (B-THg). The Odds Ratio (OR) for U-Hg above 10 μg/L for those who ate > 4 carnivorous fish

Cellulose/inorganic-composite fibers for producing textile fabrics of high X-ray absorption properties

Energy Technology Data Exchange (ETDEWEB)

Günther, Karoline; Giebing, Christina; Askani, Antonia [FTB, Hochschule Niederrhein – University of Applied Science, Faculty of Textile and Clothing Technology, Webschulstr. 31, 41065 Mönchengladbach (Germany); Leisegang, Tilmann [Saxray GmbH, Maria-Reiche-Str. 1, 01109 Dresden (Germany); Krieg, Marcus [TITK, Thüringisches Institut für Textil- und Kunststoff-Forschung e.V., Breitscheidstraße 97, 07407 Rudolstadt (Germany); Kyosev, Yordan; Weide, Thomas [FTB, Hochschule Niederrhein – University of Applied Science, Faculty of Textile and Clothing Technology, Webschulstr. 31, 41065 Mönchengladbach (Germany); Mahltig, Boris, E-mail: Boris.Mahltig@hs-niederrhein.de [FTB, Hochschule Niederrhein – University of Applied Science, Faculty of Textile and Clothing Technology, Webschulstr. 31, 41065 Mönchengladbach (Germany)

2015-11-01

Common textile materials as cotton or polyester do not possess reliable X-ray absorption properties. This is due to their morphology and chemical composition in particular. Common fibers are built up from organic polymers containing mainly the elements carbon, hydrogen, oxygen and nitrogen. These “light” elements only have low X-ray absorption coefficients. In contrast, inorganic materials composed of “heavy” elements with high atomic numbers, e.g. barium or bismuth, exhibit X-ray absorption coefficients higher by up to two orders of magnitude. To obtain a flexible yarn with high X-ray absorption properties both these materials, the organic polymer and the inorganic X-ray absorber, are combined to an inorganic/organic composite fiber material. Hence, as the organic component cellulose from modified Lyocell-process is used as carrier fiber and blended with inorganic absorber particles of low toxicity and high absorption coefficients, as bariumsulphate, bariumtitanate or bismuthoxide. A content of inorganic absorber particles equally distributed in the whole fiber of up to 20% is achieved. The composite fibers are produced as staple or filament fibers and processed to multifilament or staple fiber yarns. The staple fiber yarns are rotor-spinned to increase the comfort of the subsequent textile material. Several woven fabrics, considering multilayer structure and different warp/weft density, are developed. The energy dependent X-ray shielding properties are determined in dependence on the different yarn compositions, yarn types and structural parameters of the woven fabrics. As a result, a production process of textile materials with comfortable and dedicated X-ray absorption properties is established. It offers a promising opportunity for manufacturing of specialized textiles, working clothes or uniforms applicable for medicine, air craft and security personal, mining as well as for innovative composite materials. - Highlights: • Preparation of cellulosic

Cellulose/inorganic-composite fibers for producing textile fabrics of high X-ray absorption properties

International Nuclear Information System (INIS)

Günther, Karoline; Giebing, Christina; Askani, Antonia; Leisegang, Tilmann; Krieg, Marcus; Kyosev, Yordan; Weide, Thomas; Mahltig, Boris

2015-01-01

Common textile materials as cotton or polyester do not possess reliable X-ray absorption properties. This is due to their morphology and chemical composition in particular. Common fibers are built up from organic polymers containing mainly the elements carbon, hydrogen, oxygen and nitrogen. These “light” elements only have low X-ray absorption coefficients. In contrast, inorganic materials composed of “heavy” elements with high atomic numbers, e.g. barium or bismuth, exhibit X-ray absorption coefficients higher by up to two orders of magnitude. To obtain a flexible yarn with high X-ray absorption properties both these materials, the organic polymer and the inorganic X-ray absorber, are combined to an inorganic/organic composite fiber material. Hence, as the organic component cellulose from modified Lyocell-process is used as carrier fiber and blended with inorganic absorber particles of low toxicity and high absorption coefficients, as bariumsulphate, bariumtitanate or bismuthoxide. A content of inorganic absorber particles equally distributed in the whole fiber of up to 20% is achieved. The composite fibers are produced as staple or filament fibers and processed to multifilament or staple fiber yarns. The staple fiber yarns are rotor-spinned to increase the comfort of the subsequent textile material. Several woven fabrics, considering multilayer structure and different warp/weft density, are developed. The energy dependent X-ray shielding properties are determined in dependence on the different yarn compositions, yarn types and structural parameters of the woven fabrics. As a result, a production process of textile materials with comfortable and dedicated X-ray absorption properties is established. It offers a promising opportunity for manufacturing of specialized textiles, working clothes or uniforms applicable for medicine, air craft and security personal, mining as well as for innovative composite materials. - Highlights: • Preparation of cellulosic

Is nitrogen the next carbon?

Science.gov (United States)

Battye, William; Aneja, Viney P.; Schlesinger, William H.

2017-09-01

Just as carbon fueled the Industrial Revolution, nitrogen has fueled an Agricultural Revolution. The use of synthetic nitrogen fertilizers and the cultivation of nitrogen-fixing crops both expanded exponentially during the last century, with most of the increase occurring after 1960. As a result, the current flux of reactive, or fixed, nitrogen compounds to the biosphere due to human activities is roughly equivalent to the total flux of fixed nitrogen from all natural sources, both on land masses and in the world's oceans. Natural fluxes of fixed nitrogen are subject to very large uncertainties, but anthropogenic production of reactive nitrogen has increased almost fivefold in the last 60 years, and this rapid increase in anthropogenic fixed nitrogen has removed any uncertainty on the relative importance of anthropogenic fluxes to the natural budget. The increased use of nitrogen has been critical for increased crop yields and protein production needed to keep pace with the growing world population. However, similar to carbon, the release of fixed nitrogen into the natural environment is linked to adverse consequences at local, regional, and global scales. Anthropogenic contributions of fixed nitrogen continue to grow relative to the natural budget, with uncertain consequences.

The Global Nitrogen Cycle

Science.gov (United States)

Galloway, J. N.

2003-12-01

transfer depended on the reactivity of the emitted material. At the lower extreme of reactivity are the noble gases, neon and argon. Most neon and argon emitted during the degassing of the newly formed Earth is still in the atmosphere, and essentially none has been transferred to the hydrosphere or crust. At the other extreme are carbon and sulfur. Over 99% of the carbon and sulfur emitted during degassing are no longer in the atmosphere, but reside in the hydrosphere or the crust. Nitrogen is intermediate. Of the ˜6×106 TgN in the atmosphere, hydrosphere, and crust, ˜2/3 is in the atmosphere as N2 with most of the remainder in the crust. The atmosphere is a large nitrogen reservoir primarily, because the triple bond of the N2 molecule requires a significant amount of energy to break. In the early atmosphere, the only sources of such energy were solar radiation and electrical discharges.At this point we had an earth with mostly N2 and devoid of life. How did we get to an earth with mostly N2 and teeming with life? First, N2 had to be converted into reactive N (Nr). (The term reactive nitrogen (Nr) includes all biologically active, photochemically reactive, and radiatively active nitrogen compounds in the atmosphere and biosphere of the Earth. Thus, Nr includes inorganic reduced forms of nitrogen (e.g., NH3 and NH4+), inorganic oxidized forms (e.g., NOx, HNO3, N2O, and NO3-), and organic compounds (e.g., urea, amines, and proteins).) The early atmosphere was reducing and had limited NH3. However, NH3 was a necessary ingredient in forming early organic matter. One possibility for NH3 generation was the cycling of seawater through volcanics (Holland, 1984). Under such a process, NH3 could then be released to the atmosphere where, when combined with CH4, H2, H2O, and electrical energy, organic molecules including amino acids could be formed (Miller, 1953). In essence, electrical discharges and UV radiation can convert mixtures of reduced gases into mixtures of organic

Improvements to the Characterization of Organic Nitrogen Chemistry

Science.gov (United States)

Excess atmospheric nitrogen deposition can cause significant harmful effects to ecosystems. Organic nitrogen deposition can be an important contributor to the total nitrogen budget, contributing 10-30%, however there are large uncertainties in the chemistry and deposition of thes...