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1

12 Years of NPK Addition Diminishes Carbon Sink Potential of a Nutrient Limited Peatland  

NASA Astrophysics Data System (ADS)

Peatlands store about a third of global soil carbon. Our aim was to study whether the vegetation feedbacks of nitrogen (N) deposition lead to stronger carbon sink or source in a nutrient limited peatland ecosystem. We investigated vegetation structure and ecosystem CO2 exchange at Mer Bleue Bog, Canada, that has been fertilized for 7-12 years. We have applied 5 and 20 times ambient annual wet N deposition (0.8 g N m-2) with or without phosphorus (P) and potassium (K). Gross photosynthesis, ecosystem respiration and net CO2 exchange (NEE) were measured weekly during the growing season using chamber technique. Under the highest N(PK) treatments, the light saturated photosynthesis (PSmax) was reduced by 20-30% compared to the control treatment, whereas under moderate N and PK additions PSmax slightly increased or was similar to the control. The ecosystem respiration showed similar trends among the treatments, but changes in the rates were less pronounced. High nutrient additions led to up to 65% lower net CO2 uptake than that in the control: In the NPK plots with cumulative N additions of 70, 19, and 0 g N m-2, the daytime NEE in May-July 2011 averaged 0.8 (se. 0.3), 2.0 (se. 0.4), and 2.4 (se. 0.3) ?mol m-2 s-1, respectively. In the N only plots with cumulative N additions of 45, 19, and 0 g N m-2, the daytime NEE in May-July 2011 averaged 0.8 (se. 0.2), 2.6 (se. 0.4), and 1.8 (se. 0.3) ?mol m-2 s-1, respectively. The reduced plant photosynthetic capacity and diminished carbon sink potential in the highest nutrient treatments correlated with the loss of peat mosses and were not compensated for by the increased vascular plant biomass that has mainly been allocated to woody shrub stems.

Larmola, T.; Bubier, J. L.; Juutinen, S.; Moore, T. R.

2011-12-01

2

ADUBAÇÃO COM NPK EM COQUEIRO ANÃO-VERDE (Cocos nucifera L.) - ATRIBUTOS QUÍMICOS DO SOLO E NUTRIÇÃO DA PLANTA1  

Microsoft Academic Search

There are very few information about fertilization of coconut grown in the State of São Paulo, Brazil. So a field experiment with 'Dwarf Green' coconut was carried out to study the effects of NPK rates on some soil chemical properties and plant nutrition, from September, 2000 to February, 2004. The trial was located on an Oxisol in the west part

LUIZ ANTONIO; JUNQUEIRA TEIXEIRA; ONDINO CLEANTE BATAGLIA; SALATIÉR BUZETTI; ENES FURLANI

3

Differences in responses of summer and winter spinach to elevated UV-B at varying soil NPK levels.  

PubMed

Seasonal variations in response of spinach to elevated ultraviolet-B (UV-B) during summer and winter were assessed with respect to growth, biomass, yield, NPK uptake and NPK use efficiencies at varying NPK levels. The nutrient amendments were recommended NPK (RNPK) and 1.5 times recommended NPK (1.5 RNPK). Season significantly affected the measured parameters except the number of leaves. Under ambient UV-B, the growth performance of summer spinach was better in both the NPK levels, higher being at 1.5 RNPK leading to higher nutrient uptake. However, more reduction in biomass under elevated UV-B in 1.5 RNPK was recorded during summer, while during winter in RNPK. Reduction in biomass under elevated UV-B was accompanied by the modification in its partitioning with more biomass allocation to root during summer compared to winter at both the NPK levels. NPK uptake was higher in summer, while NPK use efficiencies were higher during winter. At higher than recommended NPK level, better NPK use efficiencies were displayed during both the seasons. Increased NPK supply during winter enabled spinach to capitalize light more efficiently and hence increased biomass accumulation. Strategies for surviving elevated UV-B in winter differ from those that provided protection from the same stress when it occurs in summer. PMID:24474564

Singh, Suruchi; Agrawal, Madhoolika; Agrawal, S B

2014-05-01

4

Obtaining granular NPK fertilizers from single superphosphate and urea  

Microsoft Academic Search

A laboratory study was conducted to elaborate methods for obtaining granular NPK fertilizers from mixtures of single superphosphate (SSP) with urea and potassium salts. Samples of products of various grades containing 32–39% fertilizer nutrients and some micronutrients (B, Cu, Co, Mo, Mn) were obtained and their characteristics determined. Instead of cured SSP the usage of a fresh den product was

E. Aasamäe; E. Arumeel; M. Einard; M. Veiderma

1993-01-01

5

Effects of NPK fertilisation in arid southern Mongolian desert steppes  

Microsoft Academic Search

Few studies have been performed on the importance of nutrient availability for plant productivity at <200 mm annual precipitation\\u000a and available meta-analyses have produced contradicting results. Here, we present data from a 3-year experiment on the effects\\u000a of NPK-fertilisation under ambient precipitation in dry Central Asian steppes. The study site had an annual mean precipitation\\u000a of ca. 160 mm and represented an

K. Wesche; K. Ronnenberg

2010-01-01

6

Phosphate solubilizers enhance NPK fertilizer use efficiency in rice and legume cultivation.  

PubMed

It has been reported that phosphate solubilizing bacteria (PSB) are the most promising bacteria among the plant growth promoting rhizobacteria (PGPR); which may be used as biofertilizers for plant growth and nutrient use efficiency. Moreover, these soil micro-organisms play a significant role in regulating the dynamics of organic matter decomposition and the availability of plant nutrients such as nitrogen (N), phosphorus (P), potassium (K) and other nutrients. Through this study, the management of nutrient use efficiency by the application of PSB was targeted in order to make the applied nutrients more available to the plants in the rice (Oryza sativa) and yardlong bean (Vigna unguiculata) cultivation. Results have shown that the treatments with PSB alone or in the form of consortia of compatible strains with or without the external application of chemical NPK gave more germination index (G. I.) from 2.5 to 5 in rice and 2.7 to 4.8 in bean seeds. They also showed a higher growth in both shoot and root length and a higher biomass as compared to the control. This gives us an idea about the potentiality of these PSB strains and their application in rice and yardlong bean cultivation to get a better harvest index. Their use will also possibly reduce the nutrient runoff or leaching and increase in the use efficiency of the applied fertilizers. Thus, we can conclude that the NPK uptake and management can be improved by the use of PSB in rice and yardlong bean cultivation, and their application may be much more beneficial in the agricultural field. PMID:22558541

Duarah, I; Deka, M; Saikia, N; Deka Boruah, H P

2011-12-01

7

Fontes de carboidratos e ionóforo em dietas contendo óleo vegetal para ovinos: digestibilidade, balanço de nitrogênio e fluxo portal de nutrientes1  

Microsoft Academic Search

RESUMO - Os objetivos neste trabalho foram avaliar a utilização de duas fontes de carboidratos (casca de soja e milho), com a utilização ou não de monensina em dietas com alta densidade lipídica, e seus efeitos sobre a digestibilidade dos nutrientes, o balanço de nitrogênio e o fluxo portal de nutrientes em ovinos. Adotou-se o método de coleta total de

Gisele Fernanda Mouro; Antonio Ferriani Branco; David Lee Harmon; Fabio José Maia

8

Effects of fertilization and irrigation on productivity, plant nutrient contents and soil nutrients in southern Mongolia  

Microsoft Academic Search

The study attempts to evaluate the effect of fertilization and irrigation on steppe productivity in dry southern Mongolian\\u000a desert-steppes. We conducted an irrigation- and NPK fertilization experiment, irrigating at levels of +100 mm and fertilizers\\u000a at amounts equivalent to 20 gN (m² year)?1 in a factorial design. We tested the effects on soil nutrients and biomass production. Nutrients in plant tissue were

Katrin Ronnenberg; Karsten Wesche

2011-01-01

9

Comparative effectiveness of cattle manure, poultry manure, phosphocompost and fertilizer-NPK on three cropping systems in vertisols of semi-arid tropics. I. Crop yields and system performance.  

PubMed

A field experiment was conducted on deep vertisols of Bhopal, India to evaluate the manural potential of three organic manures: farmyard manure (FYM), poultry manure (PM), phosphocompost (PC) vis-a-vis 0%, 75% and 100% recommended dose of fertilizer-NPK and to find out the most productive cropping system at various combinations of organic manures and chemical fertilizers. The seed yield of intercrop soybean (population converted to 100%) was 8.7% less than sole soybean whereas the grain yield of intercrop sorghum was 9.5% more than that of sole sorghum. However, the productivity in terms of soybean equivalent yield (SEY) was relatively high in intercropping system. The increasing NPK dose from 0% to 100% significantly improved SEY in sole sorghum and soybean/sorghum intercropping system and the integrated use of organics and inorganics recorded significantly more SEY than inorganics. The effect of nutrient management followed the order; 75% NPK + 5 t FYM ha(-1) > 75% NPK + 1.5 t PM ha(-1) > 75% NPK + 5 t PC ha(-1) > 100% NPK. Sorghum, both as sole and intercrop, responded more to PM while soybean to FYM. Application of 75% NPK in combination with PM or FYM or PC to preceding rainy season crops (soybean and sorghum) and 75% NPK to wheat produced significantly higher grain yield of wheat than those in inorganics and control indicating noticeable residual effect on the succeeding wheat crop and saving of 25% fertilizer-NPK. The effect of PC on rainy season crops was not as prominent as those of FYM and PM, but its residual effect on grain yield of wheat was comparable to those two organic manures. Among the cropping systems, soybean as preceding crop recorded the highest seed yield of wheat and was on a par with that of soybean/sorghum intercropping system. The yield of wheat following sorghum was the lowest. The total system productivity (TSP) was the highest in sorghum + soybean-wheat system and the lowest in the soybean-wheat system. PMID:15207299

Ghosh, P K; Ramesh, P; Bandyopadhyay, K K; Tripathi, A K; Hati, K M; Misra, A K; Acharya, C L

2004-10-01

10

Virtual and Embedded Nutrient Flows from Soybean Production in Mato Grosso, Brazil  

NASA Astrophysics Data System (ADS)

The increase in international trade of agricultural products has enabled consumers to take advantage of distant resources to secure their provision of food. However, such a relationship has also distanced consumers from producers, resulting in environmental footprints often externalized to distant countries. For example, half of all soybeans grown in the state of Mato Grosso, the largest Brazilian soybean producer this past decade, were exported to China and Europe in 2009. This study looks at nitrogen (N), phosphorous (P) and potassium (K) use related to Mato Grosso soybean production and exports to China and Europe in the 2000-2009 period. More specifically we look at 'virtual' and 'embedded' NPK flows to China and Europe, where 'virtual' represents NPK inputs associated with soybean production but not actually embedded in the exported soybeans, and 'embedded' represents the NPK contained within the soybeans. Both virtual and embedded NPK export flows more than doubled between 2000 and 2009, with embedded NPK flows up to 18 times larger than virtual flows on an annual basis. We also quantify nutrient balances resulting from the soybean trade including imported and domestically produced fertilizer. Initial results suggest that the majority of embedded N may cause an issue for importing countries, while virtual P is mostly externalized to Mato Grosso which must rely on limited national production and fertilizer imports to meet P needs. This study contributes towards a more comprehensive understanding of the use of nutrients in soybean production as a component of a more complete environmental impact assessment of this agricultural product.

Lathuilliere, M. J.; Couto, E. G.; Johnson, M. S.

2012-12-01

11

Nutrient Depletion  

NSDL National Science Digital Library

In this activity, students observe nutrient depletion as they germinate and grow nutrient-demanding seedlings. They will discover that all plants require nutrients to grow and thrive and that these nutrients are found in the soil and absorbed through the plants' root systems. They will also learn that nutrients are dissolved in water and are distributed throughout the plant via its circulatory system; when the plants are harvested, they take the nutrients with them, depleting the soil of these essential components.

12

Effect of NPK Fertilizer Levels on Morphological Characteristics and Productivity of Colchicum hierosolymitanum and Colchicum tunicatum  

Microsoft Academic Search

Colchicine, a drug used as an anti-inflammatory to treat gout condition and in tubulin-binding studies, is still obtained mainly from the meadow saffron Colchicum autumnale L. Corms of two related Jordanian species Colchicum hierosolymitanum Feibrun and Colchicum tunicatum Feibrun (Liliaceae) were collected, identified, and planted in the field at four NPK fertilizer levels. Fertilizers rates significantly modified (P < 0.05)

M. Al-Fayyad; F. Alali; A. Al-Tell

2004-01-01

13

Yield and soil nutrient balance of a sugarcane plant–ratoon system with conventional and organic nutrient management in sub-tropical India  

Microsoft Academic Search

A 3-year field trial of sugarcane, comprising 11 treatment combinations of different organic manures with and without Gluconacetobacter diazotrophicus (Gd), NPK and an absolute control, on an inceptisol was conducted to assess the effect of these treatments on sugarcane total\\u000a and economic yield, the benefit:cost ratio, nutrient balance and soil quality in a sugarcane plant–ratoon system. The highest\\u000a cane yield

K. P. Singh; Archna Suman; P. N. Singh; Menhi Lal

2007-01-01

14

Soil nutrients trump intraspecific effects on understory plant communities.  

PubMed

Understanding the links between intraspecific genetic variation and patterns of diversity in associated communities has been the primary focus of community genetics or 'genes-to-ecosystem' research in ecology. While other ecological factors, such as the abiotic environment, have well-documented influences on communities, the relative contributions of genetic variation versus the environment to species interactions remains poorly explored. In this study, we use a common garden experiment to study a coastal dune plant community dominated by the shrub, Baccharis pilularis, which displays a morphological dimorphism in plant architecture. We found the differences in the understory plant community between erect and prostrate morphs of Baccharis to be statistically significant, but small relative to the impacts of nutrient additions (NPK and C additions), for the richness, cover, and biomass of the understory plant community. There were no significant interactions between Baccharis morphology and nutrient-addition treatments, suggesting the influence of nutrient addition was consistent between erect and prostrate morphs. Moreover, we found no difference in overall plant community composition between Baccharis morphs, while NPK additions led to shifts in understory community composition compared to unfertilized shrubs. In sum, our results indicate that nutrients are the more important factor governing understory plant community structure in a coastal dunes ecosystem followed by intraspecific variation in dominant shrub architecture. Our results address a growing call to understand the extended consequences of intraspecific variation across heterogeneous environments in terrestrial ecosystems. PMID:23851987

Crutsinger, Gregory M; Carter, Benjamin E; Rudgers, Jennifer A

2013-12-01

15

Produtividade e qualidade de cana-de-açúcar cultivada em solo tratado com lodo de esgoto, vinhaça e adubos minerais  

Microsoft Academic Search

The agricultural use of organic residues is an interesting alternative to disposal allowing the recycling of nutrients (NPK) in the ecosystems. The objective of this research was to evaluate the effect of sludge application as N source and vinasse as K source when compared to the use of mineral sources of these nutrients on yield and technological variables of the

Luiz C. Tasso Júnior; Marcos O. Marques; Ademir Franco; Gustavo de A. Nogueira; Fábio O. de Nobile; Fábio Camilotti; Alysson R. da Silva

2007-01-01

16

INFLUÊNCIA DO ETEFON NA DISTRIBUIÇÃO DE NUTRIENTES E CARBOIDRATOS E SOBRE O CRESCIMENTO EM VIDEIRAS JOVENS1  

Microsoft Academic Search

Ethephon has been used in the tropical and subtropical regions of Brazil, where the vegetative growth of grapevine is continuous, with different finalities. However, little is know about the effects of this treatment on the distribution and accumulation of nutrients and carbohydrates and on the growth of grapevine. For this purpose, young plants of SO4 rootstock were sprayed with ethephon

PAULA GUERRA SCHENATO; GEORGE WELLINGTON MELO; HENRIQUE PESSOA DOS SANTOS; FLÁVIO BELLO FIALHO; GUSTAVO BRUNETTO; LIANE TEREZINHA DORNELES

17

Vegetation feedbacks of nutrient addition lead to a weaker carbon sink in an ombrotrophic bog.  

PubMed

To study vegetation feedbacks of nutrient addition on carbon sequestration capacity, we investigated vegetation and ecosystem CO2 exchange at Mer Bleue Bog, Canada in plots that had been fertilized with nitrogen (N) or with N plus phosphorus (P) and potassium (K) for 7-12 years. Gross photosynthesis, ecosystem respiration, and net CO2 exchange were measured weekly during May-September 2011 using climate-controlled chambers. A substrate-induced respiration technique was used to determine the functional ability of the microbial community. The highest N and NPK additions were associated with 40% less net CO2 uptake than the control. In the NPK additions, a diminished C sink potential was due to a 20-30% increase in ecosystem respiration, while gross photosynthesis rates did not change as greater vascular plant biomass compensated for the decrease in Sphagnum mosses. In the highest N-only treatment, small reductions in gross photosynthesis and no change in ecosystem respiration led to the reduced C sink. Substrate-induced microbial respiration was significantly higher in all levels of NPK additions compared with control. The temperature sensitivity of respiration in the plots was lower with increasing cumulative N load, suggesting more labile sources of respired CO2 . The weaker C sink potential could be explained by changes in nutrient availability, higher woody : foliar ratio, moss loss, and enhanced decomposition. Stronger responses to NPK fertilization than to N-only fertilization for both shrub biomass production and decomposition suggest that the bog ecosystem is N-P/K colimited rather than N-limited. Negative effects of further N-only deposition were indicated by delayed spring CO2 uptake. In contrast to forests, increased wood formation and surface litter accumulation in bogs seem to reduce the C sink potential owing to the loss of peat-forming Sphagnum. PMID:23868415

Larmola, Tuula; Bubier, Jill L; Kobyljanec, Christine; Basiliko, Nathan; Juutinen, Sari; Humphreys, Elyn; Preston, Michael; Moore, Tim R

2013-12-01

18

The NPK1 mitogen-activated protein kinase kinase kinase is a regulator of cell-plate formation in plant cytokinesis  

PubMed Central

Mitogen-activated protein kinase (MAPK) cascades play important roles not only in the transduction of extracellular signals but in the progression of the cell cycle. However, evidence for their role in cytokinesis is limited. Here, we show that a tobacco MAPK kinase kinase (MAPKKK), designated NPK1, is required for cytokinesis. The activity of NPK1 increases in the late M phase of the tobacco cell cycle. During expansion of a new cross-wall (cell plate) toward the cell cortex, NPK1 is consistently localized to the equatorial zone of the phragmoplast, the cytokinetic apparatus where the cell plate is formed. Expression of a kinase-negative mutant of NPK1 results in the generation of multinucleate cells with incomplete cell plates. Phragmoplasts can be formed, but its expansion toward the cell cortex is also blocked. Thus, our results indicate that the NPK1 MAPKKK is essential for the formation of the cell plate, especially for its lateral growth.

Nishihama, Ryuichi; Ishikawa, Masaki; Araki, Satoshi; Soyano, Takashi; Asada, Tetsuhiro; Machida, Yasunori

2001-01-01

19

SFRSF: Nutrients  

NSDL National Science Digital Library

This South Florida Restoration Science Forum (SFRSF) page discusses nutrient levels and loads that need to be achieved to preserve ecosystems in southern Florida. Regional issues include phosphorus concentrations and water quality. This study looks at phosphorus sources, controls for nutrient runoff, Best Management Practices for different areas (urban and rural), models of long-term transport and effects, use of natural solutions and chemical treatment solutions, and determining the effects of increased phosphorus loading on these ecosystems. There are links provided for additional information.

20

Effects of leguminous plant residues and NPK fertilizer application on the performance of yam (Dioscorea rotundata ‘c.v.’ ewuru) in south-western Nigeria  

Microsoft Academic Search

The effects of cultivating and incorporating residues of previous tropical kudzu (Pueraria phaseoloides) and soybean (Glycine max) with application of NPK fertilizer on yam performance were evaluated at the teaching and research farm, LAUTECH, Nigeria. There were nine treatments: incorporation of legume residues (5 t DM ha), application of recommended fertilizer rate for yam (90–50–75 kg NPK ha) in the zone or

Gani Oladejo Kolawole

2012-01-01

21

Nutrient omission in Bt cotton affects soil organic carbon and nutrients status  

NASA Astrophysics Data System (ADS)

Studies carried out at the University of Agricultural Sciences, Dharwad, India, in medium black soils assessed the effect of nutrient omission in Bt cotton and its effect on the soil organic carbon (SOC) and available nutrients at the end of second consecutive year of nutrient omission. The study also assessed the extent of contribution of the macro and micronutrients towards seed cotton yield. The experiment consisting 11 treatments omitting a nutrient in each treatment including an absolute control without any nutrients was conducted in a Randomised Block Design with three replications. Cotton crop sufficiently fertilized with macro and micro nutrients (165 : 75 : 120 NPK kg ha-1 and 20 kg each of CaSO4, and MgSO4, 10 kg of S, 20 kg each of ZnSO4, FeSO4 and 0.1 per cent Boron twice as foliar spray) was taken as a standard check to assess the contribution of each nutrient in various nutrient omission treatments. Soils of each treatment were analysed initially and after each crop of cotton for SOC and available nutrient status. Results indicated that the SOC decreased after each crop of cotton in absolute control where no nutrients were applied (0.50 % to 0.38 %) and also in the N omission treatment (0.50 % to 0.35 %). But there was no significant impact of omission of P, K and other nutrients on soil organic carbon. Soil available N, P and K in the soil were reduced as compared to the initial soil status after first and second crop of cotton in the respective treatment where these nutrients were omitted. The soil available N, P and K were reduced to the extent of 61 kg ha-1, 7.1 kg ha-1 and 161.9 kg ha-1 in the respective nutrient omission treatment at end of second crop of cotton as compared to the initial status of these nutrients in the soil. This might be due to the mining of these nutrients from the soil nutrient pool with out addition of these nutrients extraneously. The nutrient status of N, P and K remained almost similar in omission of other nutrients. Omission of N, P and K also reduced the seed cotton yield by 41, 9.3 and 27.3 per cent respectively. Reduction of cotton yield with omission of other nutrients was meager. It is concluded that rate of reduction in SOC, and cotton yield is more pronounced with omission of N than P and K from the regular fertiliser schedule to Bt cotton in medium black soils. However, omission of secondary and micronutrients had least effect on the soil nutrient status and seed cotton yield.

Aladakatti, Y. R.; Biradar, D. P.; Satyanarayana, T.; Majumdar, K.; Shivamurthy, D.

2012-04-01

22

Nutrient Management  

NSDL National Science Digital Library

This Iowa Department of Natural Resources PowerPoint presentation educates the public about sources of excess nutrients in the Mississippi River and outlines preventative steps to stop the influx. It is directed toward Iowa citizens, but may be applied to other states as well. This presentation features color photographs and diagrams.

2010-02-09

23

Key Nutrients.  

ERIC Educational Resources Information Center

Lessons written to help trainer agents prepare aides for work with families in the Food and Nutrition Program are presented in this booklet. The key nutrients discussed in the 10 lessons are protein, carbohydrates, fat, calcium, iron, iodine, and Vitamins A, B, C, and D. the format of each lesson is as follows: Purpose, Presentation, Application…

Federal Extension Service (USDA), Washington, DC.

24

Enhancement of growth and nutrient uptake of rapeseed (Brassica napus L.) by applying mineral nutrients and biofertilizers.  

PubMed

For investigating the effect of chemical fertilizer as well as biofertilizers on seed yield and quality i.e. oil, protein and nutrients concentration of rapeseed (Brassica napus L.), a split-plot fertilizers application experimental design in 4 replications was carried out during the 2005-2006 growing season, at the Gharakheil Agricultural Research Station in the Mazandaran province of Iran. Rapeseed was grown as a second crop in rotation after rice. Biofertilizers treatments were two different levels: control (no seed inoculation) and seeds inoculation with a combination of Azotobacter chroococcum and Azosprillum brasilense and Azosprillum lipoferum, as main plot and chemical fertilizers comprised N, P, K and their combinations, NPKS and NPK Zn as sub plots. The maximum value of seed yield obtained at (BF+NPK Zn) 3421.2 kg h(-1) corresponding to 244.5 pods per plant and maximum concentration of Zn in leaves as well as seeds. The highest weight of 1000 seeds (4.45 g) happened to obtain at (BF+NPK S) which coinciding with the maximum K levels in leaves. The highest number of branches was obtained at (BF+NPK Zn) with 4.43 branches per plant i.e., 46.2% increase over the control. The maximum value of rapeseed oil content 47.73% obtained at T16 (BF+NK) but maximum protein concentration of seed obtained at T12 (BF+N). Overall the results indicated that inoculation resulted in increase in seeds yield (21.17%), number of pods per plant (16.05%), number of branches (11.78%), weight of 1000 grain (2.92%), oil content of seeds (1.73%) and protein (3.91%) but decrease (-0.24%) in number of seeds per pods comparing to non-Biofertilizers treatments. Irrespective to the treatments, results showed that application of Biofertilizers coincided with 3.86, 0.82, 2.25, 0.75 and 0.91% increase in concentrations of N, P, K, S and Zn in the seeds over the non-Biofertilizers treatments. PMID:19579932

Yasari, Esmaeil; Azadgoleh, M A Esmaeili; Mozafari, Saedeh; Alashti, Mahsa Rafati

2009-01-15

25

Flower synchrony, growth and yield enhancement of small type bitter gourd (Momordica charantia L.) through plant growth regulators and NPK fertilization.  

PubMed

Assessment of growth regulator and NPK fertilization effects are important tools for flower stimulation and yield improvement in cucurbits. This investigation demonstrates the comparative male-female flower induction and fruit yield of small sized bitter gourd treated with NPK fertilizers and plant growth regulators. Namely, two experiments having three replicates were conducted in a Randomized Complete Block Design (RCBD) with NPK fertilization and plant growth regulators-GA3, NAA and Ethophon application on small sized bitter gourd-genotype BG5 at the research field of the Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU). In experiment 1, different doses of NPK fertilizers comprised of 10 treatments and in that of experiment 2, different levels of plant growth regulators indicated 10 treatments. The results indicated that application of different doses of NPK fertilizer and plant growth regulators significantly (< or = 0.05) influenced over the flower initiation and fruit setting. The application of N90-P45-K60 fertilizer along with Ethophon spraying resulted in the better yield of small sized bitter gourd. PMID:24897796

Mia, Baset M A; Islam, Md Serajul; Miah, Md Yunus; Das, M R; Khan, H I

2014-02-01

26

NPK1, a tobacco gene that encodes a protein with a domain homologous to yeast BCK1, STE11, and Byr2 protein kinases.  

PubMed Central

We have isolated a cDNA (cNPK1) that encodes a predicted protein kinase of 690 amino acids from suspension cultures of tobacco cells. The deduced sequence is closely related to those of the protein kinases encoded by the STE11 and BCK1 genes of Saccharomyces cerevisiae and the byr2 gene of Schizosaccharomyces pombe. STE11 and Byr2 function in the yeast mating pheromone response pathways, and BCK1 acts downstream of the yeast protein kinase C homolog encoded by the PKC1 gene, which is essential for normal growth and division of yeast cells. Overexpression in yeast cells of a truncated form of cNPK1, which encodes only the putative catalytic domain, replaced the growth control functions of BCK1 and PKC1 but not the mating pheromone response function of STE11. Thus, the catalytic domain of NPK1 specifically activates the signal transduction pathway mediated by BCK1 in yeast. In tobacco cells in suspension culture, the NPK1 gene is transcribed during logarithmic phase and early stationary phase but not during late stationary phase. In a tobacco plant, it is also transcribed in stems and roots but not in mature leaves, which rarely contain growing cells. The present results suggest that a signal transduction pathway mediated by this BCK1- and STE11-related protein kinase is also conserved in plants and that a function of NPK1 is controlled at least in part at a transcriptional level. Images

Banno, H; Hirano, K; Nakamura, T; Irie, K; Nomoto, S; Matsumoto, K; Machida, Y

1993-01-01

27

The combination of NPK fertilizer and deltamethrin insecticide favors the proliferation of pyrethroid-resistant Anopheles gambiae (Diptera: Culicidae)  

PubMed Central

In this laboratory study, we investigated how the biological cycle of Anopheles gambiae s.s. (VKPR strain) would be like when grew in an environment containing more or less plant matter (2.5 or 5 g/l) and fertilizer (8-12-8 or 17-23-17 mg/l). Half of the environments studied were not exposed to insecticide (control) whereas the other half was submitted to deltamethrin treatment at the concentration of 0.015 mg/l. The bioassays showed that 2.5 g/l of plant matter in water are not sufficient to feed the hundred larvae, each breeding site contains. Treating these breeding sites with deltamethrin reversed the situation as it decreased the competition for food resources and allowed the surviving larvae to share the small amount of food enabling them to pursue their development until adults. If the introduction of NPK in untreated sites has not improved the nutritive qualities of the water, in the treated sites it multiplied the number of emerging adults by 2.5. In the waters containing 5 g/l of plant matter, the larvae did not undergo feeding competition and the impact of insecticide followed of a more traditional selection scheme that expressed itself by a lower number of emerging adults. In these environments treated or nontreated where plant matter is abundant, adding NPK brings food supplement to the larvae therefore increases the survival rate of An. gambiae. To conclude, whether in habitats with little or much plant matter, NPK presence in water results in larger adults with generally, more soluble proteins.

Darriet, F.; Rossignol, M.; Chandre, F.

2012-01-01

28

Management of Striga hermonthica on sorghum (Sorghum bicolor) using arbuscular mycorrhizal fungi (Glomus mosae) and NPK fertilizer levels.  

PubMed

Trials were conducted in the screen house of Niger State College of Agriculture, Mokwa (09 degrees 18'N; 05 degrees 04'E) in the Southern Guinea Savannah agro-ecological zone of Nigeria during October-December, 2008 and January-March, 2009. The objective was to evaluate the effect of management of Striga hermonthica on sorghum (Sorghum bicolor) using Arbuscular mycorrhizal fungi and NPK fertilizer levels. The trials were laid out in split-split plot arrangement in a randomized complete block design. The main-plot treatments consisted of three sorghum varieties; SAMSORG 3, ICSVIII and SAMSORG 14 while the sub-plot treatments consisted of inoculations; Striga mixed with Glomus, Striga only and Glomus only as well as no inoculation control. The sub-sub-plot treatments were made up of NPK fertilizer levels; (100 kg N, 50 kg P2O5, 50 kg K2O ha(-1)), (50 kg N, 50 kg P2O5, 50 kg K2O ha(-1)) and (0 kg N, 0 kg P2O5, 0 kg K2O ha(-1)). The result obtained showed that sorghum variety SAMSORG 3 were taller, having more vigour and lower reaction to Striga parasitism which resulted in the crop producing higher dry matter compared to the other two varieties. The plots inoculated with Striga only supported shorter plants of sorghum varieties, higher vigour and lower reaction score to Striga compared to Striga mixed with Glomus. It is obvious in this study that the crop performance increases with increase in the rates of NPK fertilizer applied. PMID:24511701

Isah, K M; Kumar, Niranjan; Lagoke, S T O; Atayese, M O

2013-11-15

29

Differential response of radish plants to supplemental ultraviolet-B radiation under varying NPK levels: chlorophyll fluorescence, gas exchange and antioxidants.  

PubMed

Current and projected increases in ultraviolet-B (UV-B; 280-315 nm) radiation may alter crop growth and yield by modifying the physiological and biochemical functions. This study was conducted to assess the possibility of alleviating the negative effects of supplemental UV-B (sUV-B; 7.2 kJ m?² day?¹; 280-315 nm) on radish (Raphanus sativus var Pusa Himani) by modifying soil nitrogen (N), phosphorus (P) and potassium (K) levels. The N, P and K treatments were recommended dose of N, P and K, 1.5 times recommended dose of N, P and K, 1.5 times recommended dose of N and 1.5 times recommended dose of K. Plants showed variations in their response to UV-B radiation under varying soil NPK levels. The minimum damaging effects of sUV-B on photosynthesis rate and stomatal conductance coupled with minimum reduction in chlorophyll content were recorded for plants grown at recommended dose of NPK. Flavonoids increased under sUV-B except in plants grown at 1.5 times recommended dose of N. Lipid peroxidation (LPO) also increased in response to sUV-B at all NPK levels with maximum at 1.5 times recommended dose of K and minimum at recommended dose of NPK. This study revealed that sUV-B radiation negatively affected the radish plants by reducing the photosynthetic efficiency and increasing LPO. The plants grown at 1.5 times recommended dose of NPK/N/K could not enhance antioxidative potential to the extent as recorded at recommended dose of NPK and hence showed more sensitivity to sUV-B. PMID:22304244

Singh, Suruchi; Kumari, Rima; Agrawal, Madhoolika; Agrawal, Shashi Bhushan

2012-07-01

30

Chemical evaluation of nutrient supply from fly ash-biosolids mixtures  

SciTech Connect

Prediction of plant nutrient supply from fly ash and biosolids (sewage sludge and poultry manure) may enhance their agricultural use as crop fertilizer. Two mild extraction methods (42-d equilibration with ion-exchange resins; 2-d equilibration with pH 4.8 buffered nutrient solution) and analysis of nutrient data by the Diagnosis and Recommendation Integrated System (DRIS) were tested with 29 fly ash samples, four biosolids samples, and their mixtures. The resin method was useful for major nutrient (N, P, K, Ca, Mg, S) extraction from fly ashes and organic materials, particularly where mineralizable fractions of N and P under aerobic conditions are required. However, resins were inefficient in extracting P from high-Fe sewage sludges because organic waste samples caused premature failure of semipermeable membranes and fouling of resins. Extraction of fly ash with dilute buffered nutrient solution was more successful because micronutrient recovery was improved, major nutrients were correlated to the resin method, both addition and removal of nutrients were recorded. DRIS analysis was possible, and equilibration was rapid (2 d). The overall nutrient supply from these extremely variable fly ashes was: Cu = Fe {approx} B {approx} Mo > Ca > S > Zn >> Mn > N > Mg > P > K (high micronutrient, low major nutrient supply). For biosolids, the major nutrients ranked: P > N {approx} Ca > S > Mg > K (sewage sludges), and N > Ca {approx} K > P > Mg > S (poultry manures). In mixtures of fly ash with 26% sewage sludge the order was: Ca > S > N > Mg > P > K, while in mixtures of fly ash and 13% poultry manure, the nutrients ranked: Ca > K {approx} N {approx} S > Mg > P. Optimal plant nutrition (especially N-P-K balancing) should be possible by mixing these three waste materials.

Schumann, A.W.; Sumner, M.E.

2000-02-01

31

NOTA TÉCNICA RENDIMIENTO DE UNA PLANTACIÓN COMERCIAL DE CACAO ANTE DIFERENTES DOSIS DE FERTILIZACIÓN CON NPK EN EL SURESTE DEL ESTADO TÁCHIRA, VENEZUELA  

Microsoft Academic Search

Effect of NPK fertilization on yield of a commercial cocoa plantation at the Southeast of Táchira State, Venezuela The low cocoa yields in Venezuela are associated with lack of fertilization. Two experiments were performed in a commercial plantation in the Southeast of Táchira State to determine the plant response to several doses of fertilization. The treatments were established based on

Dercy Parra; Erbert Gamboa; José Rincón

2005-01-01

32

Nutrient Density Scores.  

ERIC Educational Resources Information Center

Announces a nutrient density food scoring system called the Index of Nutritional Quality (INQ). It expresses the ratio between the percent RDA of a nutrient and the percent daily allowance of calories in a food. (Author/SA)

Dickinson, Annette; Thompson, William T.

1979-01-01

33

NATIONAL NUTRIENTS DATABASE  

EPA Science Inventory

Resource Purpose: The Nutrient Criteria Program has initiated development of a National relational database application that will be used to store and analyze nutrient data. The ultimate use of these data will be to derive ecoregion- and waterbody-specific numeric nutrient...

34

Comparative effectiveness of cattle manure, poultry manure, phosphocompost and fertilizer-NPK on three cropping systems in vertisols of semi-arid tropics. II. Dry matter yield, nodulation, chlorophyll content and enzyme activity.  

PubMed

A field experiment was conducted on a deep Vertisol of Bhopal, India to compare root and shoot biomass, chlorophyll content, enzyme activity and nodulation in three cropping systems at three combinations of organic manure and inorganic-fertilizer: 75%NPK + 5 t farmyard manure (FYM), 75%NPK + 1.5 t poultry manure (PM), and 75%NPK + 5 t phosphocompost (PC) vis-a-vis 0%, 75% and 100% of fertilizer-NPK. In general, nodule number and its mass were lower in intercrop soybean than sole soybean. Also there was decrease in the nodule number with higher NPK dose. The FYM treated plots recorded 22.0% and 7.6% higher nodule mass than poultry manure and phosphocompost plots, respectively. Also, the total chlorophyll content was higher in organically treated plots than that in 100% NPK particularly at 30 days after sowing (DAS, pre-flowering). In sorghum the peak nitrate reductase (NR) activity was recorded at 60 DAS while in soybean it was at 30 DAS. The NR activity was higher in intercrop sorghum than that in sole sorghum. Maximum NR activity was observed in 100% NPK. Soybean/sorghum intercropping system recorded significantly higher root and shoot biomass than sole soybean and sorghum. The crop growth rates were relatively rapid during 30-60 DAS and followed the order; intercropping > sole sorghum > sole soybean. With the increase in NPK dose from 0% to 100% there was significant improvement in the dry matter (DM) production in sole sorghum and soybean/sorghum intercropping system. Soybean as preceding crop recorded the highest DM, chlorophyll content, NR activity in wheat while these values were the lowest in sorghum-wheat system. PMID:15207300

Ghosh, P K; Ajay; Bandyopadhyay, K K; Manna, M C; Mandal, K G; Misra, A K; Hati, K M

2004-10-01

35

Movement of pesticides and nutrients into tile drainage water. Final report, 22 September 1985-22 September 1988  

SciTech Connect

Concern about contamination of surface and ground water by agricultural chemicals has increased in the last five years. The objectives of this study were to determine field-scale pesticide and nutrient losses to tile drains over a 3-year period on a low-organic-matter, poorly structured silt loam soil under typical agricultural management practices. A tile-drainage spacing study was instrumented to measure water outflow rates and to continuously collect tile outflow samples on a flow-proportional basis. Two replicates of 3 tile spacings (5, 10, and 20 m) were included in the study. Water samples were analyzed for all applied pesticides (atrazine, cyanazine, alachlor, carbofuran, terbufos, and chlorpyrifos) as well as major nutrients (N,P,K) and sediment.

Van Scoyoc, G.E.; Kladivko, E.J.

1989-01-01

36

Biological soil nutrient system  

US Patent & Trademark Office Database

A biological soil nutrient system that combines beneficial soil fungi and bacteria in a growth promoting nutrient medium, embedded in an inorganic porous ceramic particle for direct delivery during soil aerification to the rhizosphere of adventitious plants, including sports turf, landscape and agricultural applications.

2010-12-21

37

Digestate as nutrient source for biomass production of sida, lucerne and maize  

NASA Astrophysics Data System (ADS)

Biogas as a renewable energy source is supported in many countries driven by climate and energy policies. Nowadays, Germany is the largest biogas producer in the European Union. A sustainable resource management has to be considered within this growing scenario of biogas production systems and its environmental impacts. In this respect, studies aiming to enhance the management of biogas residues, which represents a valuable source of nutrients and organic fertilization, are needed. Our objective was to evaluate the digestate (biogas residue after fermentation process) application as nutrient source for biomass production of three different plants: sida (Sida hermaphrodita - Malvaceae), lucerne (Medicago sativa - Fabaceae) and maize (Zea mays - Poaceae). The digestate was collected from an operating biogas facility (fermenter volume 2500m³, ADRW Natur Power GmbH & Co.KG Titz/Ameln, Germany) composed of maize silage as the major feedstock, and minor amounts of chicken manure, with a composition of 3,29% N; 1,07% P; 3,42% K; and 41,2% C. An arable field soil (Endogleyic Stagnosol) was collected from 0-30 cm depth and 5 mm sieved. The fertilizer treatments of the plants were established in five replicates including digestate (application amount equivalent to 40 t ha-1) and NPK fertilizer (application amount equivalent to 200:100:300 kg ha-1) applications, according to the recommended agricultural doses, and a control (no fertilizer application). The digestate and the NPK fertilizer were thoroughly mixed with the soil in a rotatory shaker for 30 min. The 1L pots were filled with the fertilized soil and the seedlings were transplanted and grown for 30 days under greenhouse conditions (16 h day/8 h night: 24ºC/18ºC; 60% air humidity). After harvesting, the leaf area was immediately measured, and the roots were washed to allow above and below-ground biomass determination. Subsequently, shoots and roots were dried at 60ºC for 48 hours. The biomass and leaf area of sida, lucerne and maize presented similar performance for both digestate and the NPK fertilizer applications, which were greater than the control, showing a positive fertilizing effect of the digestate for plant biomass production. Considering the biomass production obtained with the digestate application for sida, lucerne and maize, the results give support for further field experiments which aim to evaluate the fertilizing and conditioning effect of digestates.

Bueno Piaz Barbosa, Daniela; Nabel, Moritz; Horsch, David; Tsay, Gabriela; Jablonowski, Nicolai

2014-05-01

38

Hallmarks, Processing nutrients: Hanahan  

NSDL National Science Digital Library

Professor Douglas Hanahan discusses how cancer cells require a source of nutrients and oxygen, which is supplied through new blood vessel growth âÃÂàthe process of angiogenesis, which is critical for almost all cancers.

2009-12-26

39

LAKE NUTRIENT MODELING STUDY  

EPA Science Inventory

Determining the effects of morphological conditions, turbidity and watershed land use / land cover patterns on nutrient levels in Central Plains lakes and reservoirs. The study involves intensive field monitoring for the calibration and verification of basin and watershed models...

40

Influence of Npk inorganic fertilizer treatment on the proximate composition of the leaves of Ocimum gratissimum (L.) and Gongronema latifolium (benth).  

PubMed

The influence of NPK inorganic fertilizer treatment on the proximate composition of the leaves of Ocimum gratissimum (L.) and Gongronema latifolium (Benth) was investigated. Cultivated O. gratissimum and G. latifolium were treated with NPK (15:15:15) fertilizer at 100, 200, 300, 400 and 500 kg h(-1) treatment levels in planting buckets derived using the furrow slice method two months after seedling emergence. No fertilizer treatment served as control. The leaves of the plants were harvested for analysis one month after treatment. The leaf was used for the analysis because it the most eaten part. Fertilizer treatment significantly (p < 0.05) increased the dry matter, moisture content, ash, crude protein, crude fibre, crude fat contents of the leaves of both plants. On the other hand, fertilizer treatment significantly, (p < 0.05) decreased the carbohydrate and the calorific value of the leaves of the plants. The increase in the concentrations of these substances as a result of fertilizer of fertilizer treatment might be due to the role of fertilizer in chlorophyll content of plant's leaves, which in turn enhanced the process of photosynthesis leading to increased synthesis of these substances. The decrease in the carbohydrate content might be due to its conversion to other materials in the plants. The results obtained were discussed in line with current literatures. PMID:24494518

Osuagwu, G G E; Edeoga, H O

2013-04-15

41

THE QUANTITATIVEMINERAL NUTRIENT REQUIREMENTSOF PLANTS  

Microsoft Academic Search

(WITHFIVEFIGURES) Although thequalitative needsofplants forvarious mineral nutrients havebeenrecognized foroveracentury, nomethod hasbeenaccepted for measuring thequantitative mineral nutrient requirements ofplants. Herein isdeveloped arelationship between thepercentage content ofanutrient in aplant andthesufficiency ofthenutrient forgrowth. Reviewofliterature andanalysis ofprevious data LIEBIG (14)considered thepercentage nutrient content ofplants ascon- stant andthenutrient composition, therefore, asrepresenting their nutrient needs.Heproposed returning tothesoil inthefertilizer allofthe\\

PAUL MACY

42

Estimation of stream nutrient uptake from nutrient addition experiments  

SciTech Connect

Nutrient uptake in streams is often quantified by determining nutrient uptake length. However, current methods for measuring nutrient uptake length are often impractical, expensive, or demonstrably incorrect. We have developed a new method to estimate ambient nutrient uptake lengths using field experiments involving several levels of nutrient addition. Data analysis involves plotting nutrient addition uptake lengths versus added concentration and extrapolating to the negative ambient concentration. This method is relatively easy, inexpensive, and based on sound theoretical development. It is more accurate than the commonly used method involving a single nutrient addition. The utility of the method is supported by field studies directly comparing our new method with isotopic tracer methods for determining uptake lengths of phosphorus, ammonium, and nitrate. Our method also provides parameters for comparing potential nutrient limitation among streams.

Payn, Robert [Virginia Polytechnic Institute and State University (Virginia Tech)

2005-09-01

43

Nutrient Criteria Research  

EPA Science Inventory

EPA has developed methodologies for deriving nutrient criteria, default criteria for the variety of waters and eco-regions found in the U.S., and a strategy for implementing the criteria including guidance on the use and development of biocriteria. Whereas preliminary research ha...

44

SPARROW REGIONAL NUTRIENT MODEL  

EPA Science Inventory

This is the second year of funding for the New England SPARROW (Spatially Referenced Regressions on Watershed Attributes) model. Funds in the first year (along with funds allocated for projects supporting Nutrient-Criteria development) were used to analyze regional results ...

45

Assessment of the interactive effects of ambient O? and NPK levels on two tropical mustard varieties (Brassica campestris L.) using open-top chambers.  

PubMed

Rising O(3) concentrations in agricultural areas have been identified as a significant threat to crop production in Asia including India. The present work reports the results of a field study conducted to assess the usefulness of higher than recommended NPK dose in modifying the physiological, growth, yield, and seed quality responses of two mustard (Brassica campestris L. var. Vardan and Aashirwad) varieties under ambient ozone level at a rural site of India, using open-top chambers. Twelve hourly mean O(3) concentrations ranged between 27.7 and 59.04 ppb during the growth period. Plants in nonfiltered chambers (NFCs) showed reductions in photosynthetic rate, stomatal conductance, and growth parameters compared to the plants in filtered chambers (FCs), but reductions were of lower magnitude at 1.5 times recommended dose of NPK (1.5 RNPK) compared to recommended (RNPK). Yield and seed quality reduced significantly in plants of NFCs compared to FCs at RNPK, but no significant differences were recorded at 1.5 RNPK. There were higher N uptake and N uptake efficiency of plants in FCs compared to NFCs. Nitrogen utilization efficiency increased in Vardan, but decreased in Aashirwad in NFCs compared to FCs suggesting higher capability of N acquisition and utilization under ambient O(3), which led to a less pronounced reduction in the yield of the former than the latter variety. The differential nitrogen utilization efficiency in these varieties may be potentially used as measure of sensitivity characteristics in breeding programs for yield improvement in mustard under the present trend of increase in O(3) concentrations. PMID:22072445

Singh, Poonam; Singh, Shalini; Agrawal, S B; Agrawal, Madhoolika

2012-10-01

46

Nutrient formulations for disease reduction  

US Patent & Trademark Office Database

The instant invention provides a combination of multiple nutrients useful to reduce colon rectal cancer in a mannalian or human subject. Further, the combination provides synergistic ratios of the useful nutrients.

2003-11-11

47

Nutrients from Tile Drainage Systems.  

National Technical Information Service (NTIS)

Tile drainage systems of the San Joaquin Valley were monitored for nutrients (nitrogen and phosphorus). The objectives were to determine: (1) the average nutrient concentrations in tile drainage, (2) the magnitudes of annual, areal and seasonal variabilit...

W. R. Gianelli

1971-01-01

48

EFEITO DA PELETIZAÇÃO E ADIÇÃO DE ENZIMAS E VITAMINAS SOBRE O DESEMPENHO E APROVEIT AMENTO DA ENERGIA E NUTRIENTES EM FRANGOS DE COR TE DE 1 A 21 DIAS DE IDADE Effect of pelleting and addition of enzymes and vitamins on the performance and advantage of energy and nutrients in broiler chickens from 1 to 21 days old  

Microsoft Academic Search

It was carried out an experiment to evaluate the effect of pelleting and addition of enzymes and vitamins on the performance and advantage of energy and nutrients in broiler chickens from 1 to 21 days old. A total of 350 broiler chickens, COBB, males, were used ( (47g ± 2.5g) in a completely randomized design, with the treatments in a

José Laureano Barbosa Leite; Paulo Borges Rodrigues; Elias Tadeu Fialho; Rilke Tadeu; Fonseca de Freitas; Adriano Kaneo Nagata; Vinícius de Souza Cantarelli

49

Estuarine macrofauna responses to continuous in situ nutrient addition on a tropical mudflat.  

PubMed

A field experiment to assess the effects of continuous nutrient addition on the macrobenthic community was carried out on an estuarine mudflat on the northeast coast of Brazil. The experiment began on 5 October 2005 and ended on 8 February 2006. Macrofauna was compared at approximately four-week intervals in triplicate plots with three levels (Control - C, Low Dose - LD and High Dose - HD) of weekly fertilizer additions for 17weeks. Inorganic fertilizer (N-P-K) was applied on nine randomly defined quadrangular plots (4m(2) each). All measurements were calculated from species abundances. Multivariate analyses as well as the univariate indices (richness, abundance and Shannon-Wiener index) showed statistically significant differences between the enriched and control areas during the period of the experiment. The expected gradual response based on the succession model of Pearson and Rosenberg was not observed. The nutrient doses used were high enough to cause severe decreases in abundance, richness and evenness, and an increase in dominance. PMID:24835372

Botter-Carvalho, Mônica L; Carvalho, Paulo V V C; Valença, Ana Paula M C; Santos, Paulo J P

2014-06-15

50

Nutrient enrichment increased species richness of leaf litter fungal assemblages in a tropical forest.  

PubMed

Microbial communities play a major role in terrestrial ecosystem functioning, but the determinates of their diversity and functional interactions are not well known. In this study, we explored leaf litter fungal diversity in a diverse Panama lowland tropical forest in which a replicated factorial N, P, K and micronutrient fertilization experiment of 40 × 40 m plots had been ongoing for nine years. We extracted DNA from leaf litter samples and used fungal-specific amplification and a 454 pyrosequencing approach to sequence two loci, the nuclear ribosomal internal transcribed spacer (ITS) region and the nuclear ribosomal large subunit (LSU) D1 region. Using a 95% sequence similarity threshold for ITS1 spacer recovered a total of 2523 OTUs, and the number of unique ITS1 OTUs per 0.5-1.0 g leaf litter sample ranged from 55 to 177. Ascomycota were the dominant phylum among the leaf litter fungi (71% of the OTUs), followed by Basidiomycota (26% of the OTUs). In contrast to our expectations based on temperate ecosystems, long-term addition of nutrients increased, rather than decreased, species richness relative to controls. Effect of individual nutrients was more subtle and seen primarily as changes in community compositions especially at lower taxonomic levels, rather than as significant changes in species richness. For example, plots receiving P tended to show a greater similarity in community composition compared to the other nutrient treatments, the +PK, +NK and +NPK plots appeared to be more dominated by the Nectriaceae than other treatments, and indicator species for particular nutrient combinations were identified. PMID:23601077

Kerekes, Jennifer; Kaspari, Michael; Stevenson, Bradley; Nilsson, R Henrik; Hartmann, Martin; Amend, Anthony; Bruns, Thomas D

2013-05-01

51

Nutrients In Chesapeake Bay  

NSDL National Science Digital Library

The Chesapeake Bay is the largest estuary in the US. Eleven rivers empty into the bay creating the Chesapeake Bay Watershed. From urban areas and cultivated fields in which wetlands were not preserved, runoff can run into the rivers unfiltered. This runoff can include nutrients that can cause uncontrolled growth of an abundance of algae which can eventually increase the turbidity of the river, not allowing light to reach the bottom of the river. This will result in the loss of sub-aquatic vegetation (SAV) as well as the organisms which rely on it for food and habitat. There are a variety of tests that can be conducted to determine the presence of algae in the rivers. Two of these tests include pH and turbidity. In this lesson which includes field work, students will measure water quality and use authentic satellite data to explore the effects of nutrients in the Chesapeake Bay and the rivers of its watershed.

52

Nutrients, neurodevelopment, and mood  

Microsoft Academic Search

Human neurodevelopment is the result of genetic and environmental interactions. This paper examines the role of prenatal nutrition\\u000a relative to psychiatric disorders and explores the relationship among nutrients, mood changes, and mood disorders. Epidemiologic\\u000a studies have found that adults who were born with a normal, yet low birth weight have an increased susceptibility to diseases\\u000a such as coronary heart disease,

Regina C. Casper

2004-01-01

53

Siletz River nutrients: Effects of biosolids application  

EPA Science Inventory

Stream water nutrients were measured in the Siletz River, Oregon, with the goal of comparing dissolved nutrient concentrations, primarily the nitrogenous nutrients nitrate and ammonium, with previously collected data for the Yaquina and Alsea Rivers for the nutrient criteria prog...

54

USDA Nutrient Database for Standard Reference  

MedlinePLUS

... to the USDA National Nutrient Database for Standard Reference Find nutrient information on over 8,000 foods ... program, The USDA National Nutrient Database for Standard Reference, is maintained by the Nutrient Data Laboratory, Beltsville ...

55

Identification of climate-resilient integrated nutrient management practices for rice-rice cropping system—an empirical approach to uphold food security  

NASA Astrophysics Data System (ADS)

Yield datasets of long-term experiments on integrated nutrient management in rice-rice cropping systems were used to investigate the relationship of variability in rainfall, temperature, and integrated nutrient management (INM) practices in rice-rice cropping system in three different agroecological regions of India. Twelve treatments with different combinations of inorganic (chemical fertilizer) and organic (farmyard manure, green manure, and paddy straw) were compared with farmer's conventional practice. The intraseasonal variations in rice yields are largely driven by rainfall during kharif rice and by temperature during rabi rice. Half of the standard deviation from the average monthly as well as seasonal rainfall during kharif rice and 1 °C increase or decrease from the average maximum and minimum temperature during rabi rice has been taken as the classification of yield groups. The trends in the date of effective onset of monsoon indicate a 36-day delay during the 30-year period at Rajendranagar, which is statistically significant at 95 % confidence level. The mean annual maximum temperature shows an increasing trend in all the study sites. The length of monsoon also showed a shrinking trend in the rate of 40 days during the 30-year study period at Rajendranagar representing a semiarid region. At Bhubaneshwar, the application of 50 % recommended NPK through chemical fertilizers and 50 % N through green manure resulted in an overall average higher increase of 5.1 % in system productivity under both excess and deficit rainfall years and also during the years having seasonal mean maximum temperature ?35 °C. However, at Jorhat, the application of 50 % recommended NPK through chemical fertilizers and 50 % N through straw resulted in an overall average higher increase of 7.4 % in system productivity, while at Rajendranagar, the application of 75 % NPK through chemical fertilizers and 25 % N through green manusre resulted in an overall average higher increase of 8.8 % in system productivity. This study highlights the adaptive capacity of different integrated nutrient management practices to rainfall and temperature variability under a rice-rice cropping system in humid, subhumid, and semiarid ecosystems.

Subash, N.; Gangwar, B.; Singh, Rajbir; Sikka, A. K.

2014-05-01

56

Nutrient Cycling Study  

SciTech Connect

The particular goal of this study is to develop measurement techniques for understanding how consortia of organisms from geothermal facilities utilize sulfur and iron for metabolic activity; and in turn, what role that activity plays in initiating or promoting the development of a biofilm on plant substrates. Sulfur cycling is of interest because sulfur is produced in the resource. Iron is found in some of the steel formulations used in plant components and is also added as chemical treatment for reducing sulfide emissions from the plants. This report describes the set-up and operation of a bioreactor for evaluating the response of colonies of geothermal organisms to changes in nutrient and environmental conditions. Data from initial experiments are presented and plans for future testing is discussed.

Peter A. Pryfogle

2005-09-01

57

Nutrient Needs of Young Athletes.  

ERIC Educational Resources Information Center

Explains the nutritional requirements of children and adolescents, and the physiological roles of the major nutrients. Details the nutrient needs of young athletes, including pre- and postgame meals and fluid replacement. Discusses eating disorders and obesity. Advocates a diet rich in complex carbohydrates. (BC)

Willenberg, Barbara; Hemmelgarn, Melinda

1991-01-01

58

Nutrient Removal in Wastewater Treatment  

ERIC Educational Resources Information Center

Discusses the sources and effects of nutrients in wastewater, and the methods of their removal in wastewater treatment. In order to conserve water resources and eliminate the cost of nutrient removal, treated effluent should be used wherever possible for irrigation, since it contains all the ingredients for proper plant growth. (JR)

Shah, Kanti L.

1973-01-01

59

A Nutrient Density Standard for Vegetables and Fruits: Nutrients per Calorie and Nutrients per Unit Cost  

Microsoft Academic Search

ObjectivesThe Dietary Guidelines for Americans 2005 recommended that consumers give priority to nutrient-dense foods, those that contain substantial amounts of key nutrients in relation to the dietary energy they provide. This study developed a scoring system to estimate the nutritional adequacy of vegetables and fruits, on a per weight, per calorie, and per unit cost basis.

Nicole Darmon; Michel Darmon; Matthieu Maillot; Adam Drewnowski

2005-01-01

60

21 CFR 107.10 - Nutrient information.  

Code of Federal Regulations, 2010 CFR

...supplied by 100 kilocalories: Nutrients Unit of measurement Protein... (3) Each of the listed nutrients, and the caloric density, may also be declared on...that any additionally declared nutrient (i) has been...

2009-04-01

61

21 CFR 107.10 - Nutrient information.  

Code of Federal Regulations, 2010 CFR

...supplied by 100 kilocalories: Nutrients Unit of measurement Protein... (3) Each of the listed nutrients, and the caloric density, may also be declared on...that any additionally declared nutrient (i) has been...

2010-04-01

62

Ubiquitination in plant nutrient utilization  

PubMed Central

Ubiquitin (Ub) is well-established as a major modifier of signaling in eukaryotes. However, the extent to which plants rely on Ub for regulating nutrient uptake is still in its infancy. The main characteristic of ubiquitination is the conjugation of Ub onto lysine residues of acceptor proteins. In most cases the targeted protein is rapidly degraded by the 26S proteasome, the major proteolysis machinery in eukaryotic cells. The Ub-proteasome system is responsible for removing most abnormal peptides and short-lived cellular regulators, which, in turn, control many processes. This allows cells to respond rapidly to intracellular signals and changing environmental conditions. This perspective will discuss how plants utilize Ub conjugation for sensing environmental nutrient levels. We will highlight recent advances in understanding how Ub aids nutrient homeostasis by affecting the trafficking of membrane bound transporters. Given the overrepresentation of genes encoding Ub-metabolizing enzymes in plants, intracellular signaling events regulated by Ub that lead to transcriptional responses due to nutrient starvation is an under explored area ripe for new discoveries. We provide new insight into how Ub based biochemical tools can be exploited to reveal new molecular components that affect nutrient signaling. The mechanistic nature of Ub signaling indicates that dominant form of any new molecular components can be readily generated and are likely shed new light on how plants cope with nutrient limiting conditions. Finally as part of future challenges in this research area we introduce the newly discovered roles of Ub-like proteins in nutrient homeostasis.

Yates, Gary; Sadanandom, Ari

2013-01-01

63

Energy and Nutrient Intake Monitoring  

NASA Technical Reports Server (NTRS)

A passive system to determine the in-flight intake of nutrients is developed. Nonabsorbed markers placed in all foods in proportion to the nutrients selected for study are analyzed by neutron activation analysis. Fecal analysis for each market indicates how much of the nutrients were eaten and apparent digestibility. Results of feasibility tests in rats, mice, and monkeys indicate the diurnal variation of several markers, the transit time for markers in the alimentary tract, the recovery of several markers, and satisfactory use of selected markers to provide indirect measurement of apparent digestibility. Recommendations are provided for human feasibility studies.

Luckey, T. D.; Venugopal, B.; Hutcheson, D. P.

1975-01-01

64

Global Soil Nutrient Depletion and Yield Reduction  

Microsoft Academic Search

Nutrient depletion in soils adversely affects soil quality and reduces crop yield and consequently poses a potential threat to global food security and agricultural sustainability. With an emphasis on human-induced nutrient depletion, this paper described the causality among soil nutrient depletion, soil quality, crop production, socio-economic variables, and environmental condition. Then, global soil nutrient budgets of nitrogen (N), phosphorus (P),

Z. X. Tan; R. Lal; K. D. Wiebe

2005-01-01

65

Nutrient density: principles and evaluation tools.  

PubMed

Nutrient profiling is the technique of rating or classifying foods on the basis of their nutritional value. Foods that supply relatively more nutrients than calories are defined as nutrient dense. Nutrient profile models calculate the content of key nutrients per 100 g, 100 kcal, or per serving size of food. For maximum effectiveness, nutrient profile models need to be transparent, based on publicly accessible nutrient composition data, and validated against independent measures of a healthy diet. These rigorous scientific standards were applied to the development of the Nutrient-Rich Foods (NRF) family of nutrient profile models. First, the NRF models included nutrients to encourage as well as nutrients to limit. Second, NRF model performance was repeatedly tested against the Healthy Eating Index (HEI), an independent measure of a healthy diet. HEI values were calculated for participants in the 1999-2002 NHANES. Models based on 100 kcal and serving sizes performed better than those based on 100 g. Formulas based on sums and means performed better than those based on ratios. The final NRF9.3 index was based on 9 beneficial nutrients (protein; fiber; vitamins A, C, and E; calcium; iron; potassium; and magnesium) and on 3 nutrients to limit (saturated fat, added sugar, and sodium). Higher NRF9.3 scores were associated with lower energy density and more nutrient-rich diets. The nutrient density of foods, paired with a comprehensive program of consumer education, can become the foundation of dietary recommendations and guidelines. PMID:24646818

Drewnowski, Adam; Fulgoni, Victor L

2014-05-01

66

Nutrient influences on leaf photosynthesis  

SciTech Connect

The net rate of CO/sub 2/ uptake for leaves of Gossypium hirsutum L. was reduced when the plants were grown at low concentrations of NO/sub 3//sup -/, PO/sub 4//sup 2 -/, or K/sup +/. The water vapor conductance was relatively constant for all nutrient levels, indicating little effect on stomatal response. Although leaves under nutrient stress tended to be lower in chlorophyll and thinner, the ratio of mesophyll surface area to leaf area did not change appreciably. Thus, the reduction in CO/sub 2/ uptake rate at low nutrient levels was due to a decrease in the CO/sub 2/ conductance expressed per unit mesophyll cell wall area (g/sub CO/sup cell//sub 2/). The use of g/sub CO//sup cell//sub 2/ and nutrient levels expressed per unit of mesophyll cell wall provides a new means of assessing nutrient effects on CO/sub 2/ uptake of leaves. 14 figures, 1 table.

Longstreth, D.J.; Nobel, P.S.

1980-01-01

67

Integrated nutrient management for a sustainable agriculture at Omon, Vietnam  

Microsoft Academic Search

Fungal inoculant (Trichoderma sp) in powder product was used to treat into rice straw for decomposition then decomposed rice straw would be applied in combination with bio-organic phosphorus fertilizer as well as organic fertilizer. Organic fertilizer was applied alone or combined with inorganic fertilizer (NPK) in heavy clay soil to address \\

Luu Hong Man; Nguyen Ngoc Ha; Pham Sy Tan; Takao Kon; Hiroyuki Hiraoka

68

N-P-K balance in a milk production system on a C. nlemfuensis grassland and a biomass bank of P. purpureum CT115 clone  

Microsoft Academic Search

In very intensive milk production systems in Europe and America with the use of high amounts of chemical fertilizers, the nutrient recycling models consider the losses by leaching and N volatilization, as well as the hydro physical characteristics of the soil affecting the performance of this element (10; 6). However, in more extensive milk production systems, low input agriculture forming

G. Crespo; I. Rodriguez; O. Martinez

2009-01-01

69

Effect of sequential applications of foliar nutrients, biofertilizers and sowing dates on the incidence of corn stem borers in Egypt.  

PubMed

In this study either early sown (May 1st) or lately sown (June 2nd) corn plants were treated with Phosphorin & Rhizobactrin as biofertilizers and sprayed with six selected foliar nutrients, i.e. Polymex; Greenzit SP100, Greenzit NPK, Potasin-F, Copper sulphate and Ascorbic acid; in mono-, bi-, and/or tri-sequential applications. Such practices were conducted to show their beneficial effects compared with the chemical treatment in checking the incidence of the stem borers and hence increasing the corn yield. The obtained results could be summarized in the following chief points: (a) the lately sown biofertilized plants showed somewhat higher levels of infestation than the early planted ones., (b) in general, spraying the biofertilized corn plants in both sowing dates with the tested foliar nutrients, significantly decreased the rate of the stem borers infestation than the untreated plants of control., (c) the foliar sprays of Greenzit NPK alone, bi- or tri-sequential applications of Potasin-F, Polymex, Ascorbic acid and Copper sulphate achieved considerable success in reducing larval numbers of the borers species. For example, in case of using the bi-sequential nutrients (Polymex/Ascorbic acid) the numbers were 1.2, 1.5 and 1.2 larvae/5 plants, whereas the numbers were 1.3, 1.0 and 0.7 larvae/5 plants as a result, of the tri-sequential applications (Potasin-F/Ascorbic acid/Polymex) for the pink stem borer, Sesamia cretica, (Led.), the purple lined borer, Chilo agamemnon, (Bels.), and the European corn borer Ostrinia nubilalis (Hb.), in respect, vs. 4.8, 4.5 and 2.9 larvae/5 plants for the same stem borers, respectively, in case of the untreated corn plants. In addition, the other trisequential applications (Polymex/ascorbic acid/Copper sulphate), (Potasin-F/Copper sulphate/ascorbic acid) and (Potasin-F/Copper sulphate/Polymex) reduced the stem borers infestation; (d) from the view point of the interaction effects of sowing dates and the tested foliar nutrients, it was found that the tri-sequential sprayings (Potasin-F/Copper sulphate/Polymex) and/or (Potasin-F/Copper sulphate/Ascorbic acid) have lowered the rate of the stem borers infestation to 3.3 and 3.3 and 5.7 and 4.3 larvae/5 plants for the tri-applications in the 1st and 2nd sowing dates, respectively. Such reductions in the levels of infestation led to an increase in the grain yield up to 6.9 and 7.2 and 5.4 and 5.8 ton/fed, for the early and lately sown corn plants, in respect, and (e) All the foliar nutrients, with no exception, proved to be efficient in managing the stem borers infestation as compared with the insecticide treatment using Polytrin. Although the chemical application had lowered the level of infestation to 2.3 and 5.7 larvae/5 plants in the 1st and 2nd sowing dates as compared with 9.7 and 14.7 larvae/5 untreated plants for the same sowing dates, lesser grain yield of 5.6 and 4.4 ton/fed. was obtained in the first and second dates of planting, successively, in comparison to the grain yield resulted from the tri-applications of Potasin-F/Copper sulphate with either Polymex or Ascorbic acid. The abovementioned results assured the profitable effects of using foliar nutrients as well as the biofertilizers for attaining healthy corn plants, which would be capable of tolerating the injury inflicted by the studied stem borers and compensating for the harmful effects of insects infestation, so high grain yields could be obtained than those of the untreated and/or the insecticide treated plants. PMID:12696416

Mesbah, H A; Mourad, A K; el-Nimr, Hanyiat M; el-Kady, Magda B; Haroun, Nagah S

2002-01-01

70

REGIONAL CHARACTERISTICS OF NUTRIENT CONCENTRATIONS IN STREAMS AND THEIR APPLICATION TO NUTRIENT CRITERIA DEVELOPMENT  

EPA Science Inventory

In order to establish meaningful nutrient criteria, consideration must be given to the spatial variations in geographic phenomena that cause or reflect differences in nutrient concentrations in streams. Regional differences in stream nutrient concentrations were illustrated usin...

71

Nutrient conservation strategies of a mangrove species Rhizophora stylosa under nutrient limitation  

Microsoft Academic Search

Despite a growing knowledge of nutrient limitation for mangrove species and how mangroves adapt to low nutrients, there is\\u000a scant information about the relative importance of N:P ratio and leaf phenolics variability in determining nutrient conservation.\\u000a In this study, we evaluated possible nutrient conservation strategies of a mangrove Rhizophora stylosa under nutrient limitation. 1. The leaf nutrient concentrations of R.

Yi-Ming Lin; Xiao-Wei Liu; Hui Zhang; Hang-Qing Fan; Guang-Hui Lin

2010-01-01

72

Effects of biochar and clay amendment on nutrient sorption of an Arenosol in semi-arid NE-Brazil  

NASA Astrophysics Data System (ADS)

In the semi-arid Northeast of Brazil nutrient-poor Arenosol with a low capacity to retain water and nutrients is the predominant soil type. Our aim is to provide a long-term melioration of the soils with locally available and inexpensive materials. We hypothesize an increase in nutrient sorption by the addition of biochar and clay. We conducted adsorption experiments according to OECD 106 batch equilibrium method in order to test this hypothesis. Sandy Arenosol, locally produced pyrolized biochar made of Prosopis juliflora, and a clayey Vertisol with a clay content of 69.8 %, all from our project area in Pernambuco, NE-Brazil, were used. The percentage of biochar and Vertisol added were 0 % (pure Arenosol), 1 %, 2.5 %, 5 %, 10 %, 100 % (pure biochar respectively Vertisol). Samples were shaken for 24 hours in a 1:5 solid-solution ratio in six different concentrations of Ammonium-N, Nitrate-N (0 - 25 mg L-1 each), Phosphorus (0 - 19.8 mg L-1) and Potassium (0 - 50 mg L-1). These concentrations were chosen to represent a common range of nutrients in a prevalent quaternary fertilization scheme of N:P:K of 1:0.4:1, with half NH4-N and NO3-N each. Then, where possible, sorption isotherms according to Langmuir were derived. Addition of biochar and Vertisol only showed marginal effects on Ammonium sorption. We detected a high loss of Ammonium with pure biochar, we assume loss of gaseous NH3. High rates of biochar addition caused Nitrate retention. Biochar increased P sorption with a maximum adsorption capacity (qmax) of 27.35 mg kg-1 for the 5 % amendment, although some P was leached out (up to 1.58 mg kg-1 for the 10 % addition). Phosphate sorption on Vertisol was even higher with a qmax for the 5 % addition of 60.77 mg kg-1. Potassium did not sorb to biochar, but was strongly leached out (84.19 mg kg-1 out of the 5 % addition). For Vertisol we observed a strong Potassium sorption that is linear within the concentration range we tested. A possible enhancement of nutrient retention of an Arenosol by adding biochar was detected for Phosphorus and marginal for Ammonium. For Vertisol we determined a potential to retain Potassium, Phosphorus and, to a minor degree, Ammonium. For Nitrate biochar seems to have a potential to reduce losses. We suggest a mixture of Vertisol and biochar to combine the nutrient retaining effects of both materials.

Beusch, Christine; Kaupenjohann, Martin

2014-05-01

73

Influence of bio-fertilizers on the biomass yield and nutrient content in Stevia rebaudiana Bert. grown in Indian subtropics  

Microsoft Academic Search

A pot culture experiment was conducted at Indian Institute of Horticultural Research, Hessaraghata, Bangalore, India to study the effect of bio-fertilizers on the biomass yield and NPK content in Stevia (Stevia rebaudiana). The results show the yield and NPK content in stevia plant has been found to be increased initially and thereafter, the amount of the same decreased with the

Kuntal Das; Raman Dang; Nazim Sekeroglu

74

Nutrients for the aging eye  

PubMed Central

The incidence of age-related eye diseases is expected to rise with the aging of the population. Oxidation and inflammation are implicated in the etiology of these diseases. There is evidence that dietary antioxidants and anti-inflammatories may provide benefit in decreasing the risk of age-related eye disease. Nutrients of interest are vitamins C and E, ?-carotene, zinc, lutein, zeaxanthin, and the omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid. While a recent survey finds that among the baby boomers (45–65 years old), vision is the most important of the five senses, well over half of those surveyed were not aware of the important nutrients that play a key role in eye health. This is evident from a national survey that finds that intake of these key nutrients from dietary sources is below the recommendations or guidelines. Therefore, it is important to educate this population and to create an awareness of the nutrients and foods of particular interest in the prevention of age-related eye disease.

Rasmussen, Helen M; Johnson, Elizabeth J

2013-01-01

75

Wastewater Treatment with Plants in Nutrient Films.  

National Technical Information Service (NTIS)

The nutrient film technique (NFT) is a unique modification of a hydroponic plant growth system which utilizes plants growing on an impermeable surface. A thin film of water flowing through the extensive root system provides nutrients for plants and associ...

H. DeLancey-Pompe J. J. Madras R. M. Kabrick W. J. Jewell W. W. Clarkson

1983-01-01

76

Confined Animal Production and Manure Nutrients.  

National Technical Information Service (NTIS)

Census of agriculture data were used to estimate manure nutrient production and the capacity of cropland and pastureland to assimilate nutrients. Most farms (78 percent for nitrogen and 69 percent for phosphorus) have adequate land on which it is physical...

C. Lander D. Letson M. Caswell N. Gollehon R. Kellogg R. Ribaudo

2001-01-01

77

Protein accumulation and composition in wheat grains: Effects of mineral nutrients and high temperature  

Microsoft Academic Search

Effects of mineral nutrition and temperature on accumulation and composition of protein in wheat grains and on baking quality were studied under controlled environments. Under a moderate temperature regimen of 24°C days and 17°C nights (24\\/17°C), post-anthesis N:P:K 20:20:20 (NPK) supplied by continuous drip irrigation increased the rate of protein accumulation, doubled flour protein percentage and slightly increased final single

Frances M. Dupont; William J. Hurkman; William H. Vensel; Charlene Tanaka; Kerry M. Kothari; Okkyung K. Chung; Susan B. Altenbach

2006-01-01

78

DISTRIBUIÇÃO DE BIOMASSA E NUTRIENTES NA PARTE AÉREA DE Mimosa caesalpiniaefolia BENTH1  

Microsoft Academic Search

RESUMO - O trabalho foi realizado na Estação Experimental de Itambé, PE, para avaliar a distribuição da biomassa e nutrientes em povoamentos de Mimosa caesalpiniaefolia Benth. Foram estudados dois povoamentos, em solo e topografia similares com oito e 11 anos de idade, nos espaçamentos de 3,0 x 3,0 m e 4,5 x 4,5 m, respectivamente. A biomassa foi determinada para

Orieudo Nunes Moura; Marco Antônio Amaral Passos; Rinaldo Luiz Caraciolo Ferreira; Silmar Gonzaga Molica; Mario de Andrade; Lira Junior

2006-01-01

79

NUTRIENT CRITERIA DEVELOPMENT FOR R10 ECOREGIONS.  

EPA Science Inventory

Excess nutrients in waters of the northwest are one of the top contributors to water quality impairment. EPA, states and Tribes lack quantifiable targets for nutrients in the water quality standards. Water quality standards for nutrients usually use narrative language, such as ...

80

Nutrient control of bacterioplankton and phytoplankton dynamics  

Microsoft Academic Search

To determine whether positive correlations between phytoplankton and bacterioplankton growth in nutrient addi- tion experiments are due to growth coupling or growth stimulation by the same nutrients, we examined phyto- and bacterioplankton growth in a series of eleven nutrient addition (N P) and light\\/dark experiments. In mesotrophic Castle Lake, the phyto- and bacterioplankton growth responses to phosphorus (P) addition were

Michael T. Brett; Fred S. Lubnow; Manuel Villar-Argaiz; Anke Müller-Solger; Charles R. Goldman

1999-01-01

81

Low soil temperature inhibits the effect of high nutrient supply on photosynthetic response to elevated carbon dioxide concentration in white birch seedlings.  

PubMed

To investigate the interactive effects of soil temperature (T(soil)) and nutrient availability on the response of photosynthesis to elevated atmospheric carbon dioxide concentration ([CO(2)]), white birch (Betula papyrifera Marsh.) seedlings were exposed to ambient (360 micromol mol(-1)) or elevated (720 micromol mol(-1)) [CO(2)], three T(soil) (5, 15 and 25 degrees C initially, increased to 7, 17 and 27 degrees C, respectively, 1 month later) and three nutrient regimes (4/1.8/3.3, 80/35/66 and 160/70/132 mg l(-1) N/P/K) for 3 months in environment-controlled greenhouses. Elevated [CO(2)] increased net photosynthetic rate (A(n)), instantaneous water-use efficiency (IWUE), internal to ambient carbon dioxide concentration ratio (C(i)/C(a)), triose phosphate utilization (TPU) and photosynthetic linear electron transport to carboxylation (J(c)), and it decreased actual photochemical efficiency of photosystem II (DeltaF/F(m)'), the fraction of total linear electron transport partitioned to oxygenation (J(o)/J(T)) and leaf N concentration. The low T(soil) suppressed A(n), transpiration rate (E), TPU, DeltaF/F(m)' and J(c), but it increased J(o)/J(T). The low nutrient treatment reduced A(n), IWUE, maximum carboxylation rate of Rubisco, light-saturated electron transport rate, TPU, DeltaF/F(m)', J(c) and leaf N concentration, but increased C(i)/C(a). There were two-factor interactions for C(i)/C(a), TPU and leaf N concentration, and a significant effect of CO(2) x T(soil) x nutrient regime on A(n), IWUE and J(c). The stimulations of A(n) and IWUE by elevated [CO(2)] were limited to seedlings grown under the intermediate and high nutrient regimes at the intermediate and high T(soil). For J(c), the [CO(2)] effect was significant only at intermediate T(soil) + high nutrient availability. No significant [CO(2)] effects were observed under the low T(soil) at any nutrient level. Our results support this study's hypothesis that low T(soil) would reduce the positive effect of high nutrient supply on the response of A(n) to elevated [CO(2)]. PMID:20007132

Ambebe, Titus F; Dang, Qing-Lai; Li, Junlin

2010-02-01

82

Biomass and nutrient allocation of sawgrass and cattail along a nutrient gradient in the Florida Everglades  

Microsoft Academic Search

Biomass and nutrient allocation in sawgrass (Cladium jamaicense Crantz) and cattail (Typha domingensis Pers.) were examined along a nutrient gradient in the Florida Everglades in 1994. This north to south nutrient gradient, created by discharging nutrient-rich agricultural runoff into the northern region of Water Conservatio ea 2A, was represented by three areas (impacted, transitional and reference). Contrasting changes of plant

S. L. Miao; F. H. Sklar

1997-01-01

83

Automated nutrient analyses in seawater  

SciTech Connect

This manual was assembled for use as a guide for analyzing the nutrient content of seawater samples collected in the marine coastal zone of the Northeast United States and the Bering Sea. Some modifications (changes in dilution or sample pump tube sizes) may be necessary to achieve optimum measurements in very pronounced oligotrophic, eutrophic or brackish areas. Information is presented under the following section headings: theory and mechanics of automated analysis; continuous flow system description; operation of autoanalyzer system; cookbook of current nutrient methods; automated analyzer and data analysis software; computer interfacing and hardware modifications; and trouble shooting. The three appendixes are entitled: references and additional reading; manifold components and chemicals; and software listings. (JGB)

Whitledge, T.E.; Malloy, S.C.; Patton, C.J.; Wirick, C.D.

1981-02-01

84

Foods, nutrients and prostate cancer  

Microsoft Academic Search

Objective: To examine the risk of prostate cancer associated with foods and nutrients, including individual fatty acids and carotenoids. Methods: Population-based case–control study of 858 men aged Results: Inverse associations with prostate cancer were observed for (Odds ratio, OR, 95% confidence intervals, 95% CI for tertile III compared with tertile I) allium vegetables 0.7, 0.5–0.9; p trend 0.01, tomato-based foods

Allison M. Hodge; Dallas R. English; Margaret R. E. McCredie; Gianluca Severi; Peter Boyle; John L. Hopper; Graham G. Giles

2004-01-01

85

Spectral Quantitation Of Hydroponic Nutrients  

NASA Technical Reports Server (NTRS)

Instrument continuously monitors hydroponic solution by use of absorption and emission spectrometry to determine concentrations of principal nutrients, including nitrate, iron, potassium, calcium, magnesium, phosphorus, sodium, and others. Does not depend on extraction and processing of samples, use of such surrograte parameters as pH or electrical conductivity for control, or addition of analytical reagents to solution. Solution not chemically altered by analysis and can be returned to hydroponic process stream after analysis.

Schlager, Kenneth J.; Kahle, Scott J.; Wilson, Monica A.; Boehlen, Michelle

1996-01-01

86

Nutrients in the Atlantic thermocline  

SciTech Connect

A set of maps are presented of nutrient distribution on isopycnal surfaces in the North and tropical Atlantic Ocean main thermocline. The data used in producing these maps are from the Transient Tracers in the Oceans (TTO) North Atlantic Study and Tropical Atlantic Study, an associated German study (Meteor 56/5), two cross-Atlantic sections from cruise 109 of the Atlantis II, and the GEOSECS program. The nutrient distributions reflect primarily the sources at the northern and southern outcrops of the isopycnal surfaces, the in situ regeneration due to decomposition of sinking organic materials, and the interior physical processes as inferred from thermocline models and the distribution of conservative properties such as salinity. However, silica also exhibits behavior that cannot be explained by in situ regeneration. A simple phenomenological model suggests that cross-isopycnal advection and mixing in the equatorial region may play an important role in the nutrient dynamics. These data should prove of great value in constraining models of physical as well as biogeochemical processes. 43 references, 12 figures, 1 table.

Kawase, M.; Sarmiento, J.L.

1985-09-20

87

Nutrient Cycling in Piermont Marsh  

NASA Astrophysics Data System (ADS)

We investigate the cycling of nutrients through a brackish tidal wetland about 40 km north of Manhattan in the Hudson River estuary. As part of a long-term ecological study of Piermont Marsh, a NOAA reference wetland managed by the NY State DEC, we are measuring dissolved inorganic nutrients on the Marsh surface and its drainage channels. The marsh occupies 400 acres along the southwest corner of Haverstraw Bay with approximately 2 km frontage to the estuary. It is supplied with nutrient-rich water and drained primarily along several tidal creeks and the hundreds of rivulets that feed them. During most tidal cycles the silty berm bounding the marsh is not topped. Human influence in the marsh's surrounding area has had profound effects, one of the most fundamental of which has been the shift from native grass species, predominantly Spartina alterniflora, to an invasive genotype of common reed, Phragmites australis. Along with this shift there have been changes in the root bed, the effective marsh interior and berm heights, the hydroperiod and, as a result, the ability of the marsh to be utilized by various types of Hudson estuary fish. The vegetative shift is believed to be anthropogenic, but the connection is not well understood, and it is not known what role biogeochemical perturbations are playing. We present two field seasons of nitrate, phosphate and silicate measurements from Sparkill Creek, a freshwater stream draining the surrounding highlands constitutes the northern boundary, two tidally driven creeks transect the Marsh from West to East: the Crumkill and an unnamed creek we have dubbed the "Tidal", Ludlow Ditch, a no-longer-maintained drainage channel grading gently from the northern part of the marsh to the South terminates in a wide tidal outlet that is its southern boundary. Net tidal cycle fluxes and fluxes resulting from runoff events are presented. Deviations from Redfield ratios and limiting nutrients are analyzed. Piermont Marsh data is compared to prior studies of the other three NOAA-managed reference marshes in the Hudson Valley. The data supplements carbon content data (presented in a companion poster) to estimate the carbon cycling and sequestration capacity of the Marsh sediments. Nutrient data is being collected as one component of a broad ecological and geochemical study of the Marsh and its adaptation to human influence (see companion posters on carbon cycling and habitat utilization in the Marsh). All data were collected and analyzed as part of Lamont-Doherty Secondary School Field Research Program, which engages NYC high school teachers and students in research in the Hudson/Raritan estuarine environment.

Reyes, N.; Gribbin, S.; Newton, R.; Diaz, K.; Laporte, N.; Trivino, G.; Ortega, J.; McKee, K.; Sambrotto, R.

2011-12-01

88

Nutrient Management in Recirculating Hydroponic Culture  

NASA Technical Reports Server (NTRS)

There is an increasing need to recirculate and reuse nutrient solutions in order to reduce environmental and economic costs. However, one of the weakest points in hydroponics is the lack of information on managing the nutrient solution. Many growers and research scientists dump out nutrient solutions and refill at weekly intervals. Other authors have recommended measuring the concentrations of individual nutrients in solution as a key to nutrient control and maintenance. Dumping and replacing solution is unnecessary. Monitoring ions in solution is not always necessary; in fact the rapid depletion of some nutrients often causes people to add toxic amounts of nutrients to the solution. Monitoring ions in solution is interesting, but it is not the key to effective maintenance.

Bugbee, Bruce

2004-01-01

89

Soil Moisture, Plant Nutrient Uptake, and Computer Simulation of Nutrient Export  

NASA Astrophysics Data System (ADS)

Correct estimate of nutrient discharge from soil is important in nutrient management for protecting water quality of receiving water. Solute property, soil physical and chemical property, climatic factors, water supplies, microorganism activities, and plant uptake play important rolls in sub-ground nutrient cycle. Soil water movement provides forcing for transport of dissolved nutrients within the soil and their discharge from land to a receiving water. Solute export is proportional to water discharge and solute concentration in the soil pool. Plant uptake reduces the amount of nutrient in the soil and reduces export potential. Soil moisture level has a significant effect on the uptake of nutrient by plant, which involves both solute transport and complex physiological responses of plant. Plant nutrient uptake is not a monotonic function with soil moisture. Experiments show that plant uptake increases from a dry soil to moist soil, hence, reducing the potential of nutrient export. However, when moisture is over-sufficient in a wet soil, then more moisture would not cause higher nutrient uptake but increase export potential due to higher water discharge. This paper discusses the relationship among soil moisture, nutrient concentration, evapotranspiration, plant nutrient uptake and nutrient export from land, and presents a computer model on these processes, providing a method to simulate plant nutrient uptake and nutrient export under various moisture conditions.

Wang, P.; Linker, L. C.

2005-05-01

90

Insects, infestations and nutrient fluxes  

NASA Astrophysics Data System (ADS)

Forest ecosystems are characterized by a high temporal and spatial variability in the vertical transfer of energy and matter within the canopy and the soil compartment. The mechanisms and controlling factors behind canopy processes and system-internal transfer dynamics are imperfectly understood at the moment. Seasonal flux diversities and inhomogeneities in throughfall composition have been reported from coniferous and deciduous forests, and in most cases leaf leaching has been considered as principle driver for differences in the amount and quality of nutrients and organic compounds (Tukey and Morgan 1963). Since herbivorous insects and the processes they initiate received less attention in past times, ecologists now emphasize the need for linking biological processes occurring in different ecosystem strata to explain rates and variability of nutrient cycling (Bardgett et al. 1998, Wardle et al. 2004). Consequently, herbivore insects in the canopies of forests are increasingly identified to play an important role for the (re)cycling and availability of nutrients, or, more generally, for the functioning of ecosystems not only in outbreak situations but also at endemic (non-outbreak) density levels (Stadler et al. 2001, Hunter et al. 2003). Before, little attention was paid to insect herbivores when quantifying element and energy fluxes through ecosystems, although the numerous and different functions insects fulfill in ecosystems (e.g. as pollinators, herbivores or detritivores) were unanimously recognized (Schowalter 2000). Amongst the reasons for this restraint was the argument that the total biomass of insects tends to be relatively low compared to the biomass of trees or the pool of soil organic matter (Ohmart et al. 1983). A second argument which was put forward to justify the inferior role of insects in nutrient cycling were the supposed low defoliation losses between 5-10% of the annual leaf biomass, or net primary production, due to insect herbivory under endemic situations (Larrson and Tenow 1980). However, at times of insect mass outbreaks with leaf area losses up to 100%, nutrient fluxes are strongly affected at the ecosystem level and consequently attract greater attention (Grace 1986). In this context, mass outbreaks of herbivore insects constitute a class of ecosystem disturbance (Pickett and White 1985). More specific, insect pests meet the criteria of biogeochemical "hot spots" and "hot moments" (McClain et al. 2003) as they induce temporal-spatial process heterogeneity or changes in biogeochemical reaction rates, but not necessarily changes in the structure of ecosystems or landscapes. This contribution presents a compilation of literature and own research data on insect herbivory effects on nutrient cycling and ecosystem functioning from the plot to the catchment scale. It focuses on temperate forest ecosystems and on short-term impacts as exerted by two focal functional groups of herbivore canopy insects (leaf and sap feeders). In detail, research results on effects operating on short temporal scales are presented including a) alterations in throughfall fluxes encompassing dissolved and particulate organic matter fractions, b) alterations in the amount, timing and quality of frass and honeydew deposition and c) soil microbial activity and decomposition processes.

Michalzik, B.

2012-04-01

91

Nutrient transports in a Swedish estuary  

NASA Astrophysics Data System (ADS)

Himmerfjärd is a Swedish estuary bordering on the Baltic. The estuary lacks astronomical tides and its circulation is driven by winds and freshwater runoff. Because of a tertiary sewage treatment plant located at its inner end, the estuary is becoming increasingly eutrophic. A field study was carried out for a 78-day period in late summer and early fall of 1977 to determine rates of nutrient transport and to construct nutrient budgets. Since physical parameters (current velocity, temperature, salinity, winds and water level changes) were measured more frequently than nutrients (phosphate, nitrate, nitrite and ammonium) it was necessary to develop a suitable method to calculate nutrient flux time series and net nutrient fluxes. Over the study period, Himmerfjärd imported phosphorus and exported nitrogen. Direction of nutrient fluxes and changes in flux direction were consistent with the structure of the baroclinic currents.

Wilmot, Wayne; Toll, Peter; Kjerfve, Björn

1985-08-01

92

Managing urban nutrient biogeochemistry for sustainable urbanization.  

PubMed

Urban ecosystems are unique in the sense that human activities are the major drivers of biogeochemical processes. Along with the demographic movement into cities, nutrients flow towards the urban zone (nutrient urbanization), causing the degradation of environmental quality and ecosystem health. In this paper, we summarize the characteristics of nutrient cycling within the urban ecosystem compared to natural ecosystems. The dynamic process of nutrient urbanization is then explored taking Xiamen city, China, as an example to examine the influence of rapid urbanization on food sourced nitrogen and phosphorus metabolism. Subsequently, the concept of a nutrient footprint and calculation method is introduced from a lifecycle perspective. Finally, we propose three system approaches to mend the broken biogeochemical cycling. Our study will contribute to a holistic solution which achieves synergies between environmental quality and food security, by integrating technologies for nutrient recovery and waste reduction. PMID:24746891

Lin, Tao; Gibson, Valerie; Cui, Shenghui; Yu, Chang-Ping; Chen, Shaohua; Ye, Zhilong; Zhu, Yong-Guan

2014-09-01

93

Rhizosphere Priming: a Nutrient Perspective  

NASA Astrophysics Data System (ADS)

Rhizosphere priming is the change in decomposition of soil organic matter (SOM) caused by root activity. Rhizosphere priming plays a crucial role in soil carbon (C) dynamics and their response to global climate change. Rhizosphere priming may be affected by soil nutrient availability, but rhizosphere priming itself can also affect nutrient supply to plants. We postulate that rhizosphere priming on soil C may occur in nitrogen (N) limited but not in phosphorus (P) limited systems. Under N limitation, root exudates may be utilised by microbes stimulating oxidation of soil C thereby releasing N. On the other hand, under P limitation, rhizodeposition may be used for P hydrolysis, desorption, dissolution and mobilisation processes without affecting C decomposition. We illustrate this hypothesis with results from two field experiments in semiarid grasslands (Colorado and Wyoming study) affected by elevated atmospheric CO2. We found that an increase in rhizosphere priming under elevated CO2 enhanced the release of N through decomposition of a larger fraction of SOM in the Colorado study, but not in the Wyoming study. This contrast in N cycling may have been caused by N limitation in the Colorado and P limitation in the Wyoming study. Therefore, with increasing atmospheric CO2 concentrations, rhizosphere priming may play a larger role in affecting C sequestration in N poor than in P poor soils.

Dijkstra, F. A.; Carrillo, Y.; Pendall, E. G.; Morgan, J. A.

2013-12-01

94

[Nutrient supplements - possibilities and limitations].  

PubMed

The consumption of micronutrient-supplements by the general public has become widespread; between 25 and more than 40% of individuals questioned in western developed nations confirm to regularly consume such products. In principle, there are two product categories for micronutrient-supplements - medicinal products (drugs) and foodstuffs. The latter are marketed as food supplements (FS) and dietary foodstuffs for particular nutritional uses including foods for special medical purposes (FSMP). FS serve the general supplementation of any consumer whilst foodstuffs for particular nutritional uses are directed at consumers with special dietary requirements; FSMP are intended for the dietary management of patients. There are clearly defined legal frameworks for those product categories. Independently of their legal product status, six areas of application can be characterised for micronutrient-supplements: general and special supplementation, primary prevention, compensation of disease-related deficits, therapeutic function and containment of diseases or avoidance of subsequent damages (secondary and tertiary function). Gauged with the mean-intake, micro nutrient supply in Germany is sufficient (exception: folic acid and vitamin D; partially also iodine). However, the intake of vitamins E, C, B1 and B2 as well as the minerals calcium, magnesium, zinc and iodine could be improved in 20-50% of the general public. Micro nutrient preparations in physiological dose could contribute to closing this gap in supply. PMID:23758028

Ströhle, Alexander; Hahn, Andreas

2013-05-01

95

Nutrient sensing, metabolism, and cell growth control  

PubMed Central

Summary Cell growth is regulated by coordination of both extracellular nutrients and intracellular metabolite concentrations. AMP activated kinase and mammalian target of rapamycin complex 1 serve as key molecules that sense cellular energy and nutrients levels, respectively. In addition, the dioxygenase family, including prolylhydroxylase, lysine demethylase, and DNA demethylase, has emerged as possible sensors of intracellular metabolic status. The interplay among nutrients, metabolites, gene expression, and protein modification are involved in the coordination of cell growth with extracellular and intracellular conditions.

Yuan, Hai-Xin; Xiong, Yue; Guan, Kun-Liang

2013-01-01

96

Can Nutrient Spiralling be Used to Detect Seasonal Nutrient Uptake in a Forested Stream?  

Microsoft Academic Search

Nutrient spiralling measurements were conducted in Lyrebird Creek, a forested stream in the Dandenong Ranges, Victoria, Australia.\\u000a Spiralling indices from several nutrient ($${\\\\text{NH}}^{ + }_{4} $$, $${\\\\text{PO}}^{{3 - }}_{4} $$) enrichment experiments were correlated with seasonal variation in factors thought to control nutrient uptake, i.e., temperature,\\u000a light and algal biomass. It was hypothesized that nutrient uptake would be higher in

Sulfikar Hanafi; Michael R. Grace; Barry T. Hart

2006-01-01

97

DETERMINAÇÃO DE NUTRIENTES MINERAIS EM PLANTAS MEDICINAIS 1  

Microsoft Academic Search

SUMMARY DETERMINATION OF MINERALS IN MEDICINAL PLANTS. The use of vegetables has become widely spread as nourishment, medicinal and cosmetic purposes in recent years. Due to the importance of the analytical study of this class of plants, and considering the growing interest about their inorganic composition that can be represented by the significant number of publications during the last years,

Maria Mozarina; Beserra ALMEIDA; Maria de Fátima; Gomes LOPES; Célia Maria Diógenes NOGUEIRA; Carlos Emanuel de Carvalho; Noélia Maria Tavares de MORAIS

98

Nutrient limitations on peat decomposition and nutrient loading in Atlantic White Cedar swamps  

Microsoft Academic Search

Like many wetlands, Atlantic White Cedar (Chamaecyparis thyoides) swamps are experiencing anthropogenic disturbances causing changes in hydrology and increased nutrient loading. In this study, I examined the effects of nutrient increases on peat decomposition. I analyzed peat and porewater nutrients in two initial cores. I incubated eight cores in the laboratory—two fertilized with phosphate, two fertilized with nitrate, two fertilized

CAITLIN E. HICKS

99

NUTRIENT CRITERIA DEVELOPMENT WITH A LINKED MODELING SYSTEM: CALIBRATION OF AQUATOX ACROSS A NUTRIENT GRADIENT  

Microsoft Academic Search

Nutrients (nitrogen and phosphorus) are leading causes of water quality impairment in the Nation's rivers, lakes and estuaries. To address this problem, states need the technical resources to establish nutrient criteria, adopt them into their water quality standards, and implement them in regulatory programs. In recent years EPA developed and finalized a series of nutrient criteria documents to assist the

Richard A. Park; Jonathan S. Clough; Marjorie C. Wellman; Anthony S. Donigian

100

NUTRIENT-UPTAKE MODEL IN MARSH ECOSYSTEMS  

EPA Science Inventory

Mechanistic models of nutrient dynamics in natural wetlands were developed and applied in a study of Kissimmee River (Florida) flood-plain marshes. The models describe hydrodynamics and transport diffusion in wetland basins and the ecological processes of nutrient uptake, convers...

101

Assessing Nutrient Recovery from Piggery Effluents  

Microsoft Academic Search

The past few decades has seen an increase in livestock intensification within the Australian pig industry, which has lead to a waste management problem due to increased volumes of nutrient rich effluent leaving these facilities. Land application of these nutrient-rich effluents is economically and environmentally unsustainable in some circumstances. One promising alternative is to remove the nitrogen and phosphorus compounds

M. I. Ali; P. A. Schneider; N. Hudson

102

A Method for Developing a Nutrient Guide.  

ERIC Educational Resources Information Center

This paper proposes a new approach to developing a tool for teaching nutrition and food selection. It allows adjustments as new information becomes available and takes into account both dietary recommendations and food composition. Steps involve nutrient composition; nutrient density; and ratings for fat, cholesterol, and sodium. (Author/CT)

Gillespie, Ardyth H.; Roderuck, Charlotte E.

1982-01-01

103

Nutrient Adequacy of Urban Food Assistance Provisions  

Microsoft Academic Search

LEARNING OUTCOME: To examine nutrient composition of a random sample of emergency food bagsContinued expansion of private food assistance has sensitized dietitians to the need to understand what foods and nutrients are being offered. Fifty-seven food assistance sites with provision of emergency food as a primary objective were sorted into strata using the number of clients served as the indicator

L. Jacobs Starkey; H. V. Kuhnlein

1996-01-01

104

Enteral feeding: Drug\\/nutrient interaction  

Microsoft Academic Search

Enteral nutrition support via a feeding tube is the first choice for artificial nutrition. Most patients also require simultaneous drug therapy, with the potential risk for drug–nutrient interactions which may become relevant in clinical practice. During enteral nutrition, drug–nutrient interactions are more likely to occur than in patients fed orally. However, there is a lack of awareness about its clinical

R. LOURENÇO

2001-01-01

105

WASTEWATER TREATMENT WITH PLANTS IN NUTRIENT FILMS  

EPA Science Inventory

The nutrient film technique (NFT) is a unique modification of a hydroponic plant growth system which utilizes plants growing on an impermeable surface. A thin film of water flowing through the extensive root system provides nutrients for plants and associated microbial growth. Ro...

106

Modelling nutrient cycling in forest ecosystems.  

National Technical Information Service (NTIS)

Acid deposition's threat to fresh water and forest environments became an issue in the late 1960s. Acid deposition and forest nutrient cycling then began to be researched in greater co-operation. This thesis studies nutrient cycling processes in Norway sp...

S. H.S.B. Kvindesland

1997-01-01

107

SSMILes: Measuring the Nutrient Tolerance of Algae.  

ERIC Educational Resources Information Center

Presents an activity integrating mathematics and science intended to introduce students to the use of metric measurement of mass as a way to increase the meaningfulness of observations about variables in life sciences. Involves measuring the nutrient tolerance of algae. Contains a reproducible algae nutrient graph. (Author/MKR)

Hedgepeth, David J.

1995-01-01

108

SUBMERGED MACROPHYTE EFFECTS ON NUTRIENT EXCHANGES IN RIVERINE SEDIMENTS  

EPA Science Inventory

Submersed macrophytes are important in nutrient cycling in marine and lacustrine systems, although their role in nutrient exchange in tidally-influenced riverine systems is not well studied. In the laboratory, plants significantly lowered porewater nutrient pools of riverine sedi...

109

21 CFR 101.69 - Petitions for nutrient content claims.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 false Petitions for nutrient content claims. 101.69 Section 101.69 ...LABELING Specific Requirements for Nutrient Content Claims § 101.69 Petitions for nutrient content claims. (a) This section pertains...

2009-04-01

110

21 CFR 101.69 - Petitions for nutrient content claims.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Petitions for nutrient content claims. 101.69 Section 101.69 ...LABELING Specific Requirements for Nutrient Content Claims § 101.69 Petitions for nutrient content claims. (a) This section pertains...

2010-04-01

111

Nutrient elements in large Chinese estuaries  

NASA Astrophysics Data System (ADS)

Based on comprehensive observations since 1983, this study summarizes major features of nutrient elements (nitrogen, phosphorus and silicon) in large Chinese river/estuary systems. Elevated nutrient element levels were observed in Chinese rivers, when compared to large and less disturbed aquatic systems (e.g. the Amazon, Zaire and Orinoco). Data from this study are similar to those obtained from the polluted and/or eutrophic rivers in Europe and North America (e.g. the Rhóne and Loire). Nutrient elements may have either conservative or active distributions, or both, in the mixing zone, depending on the element and the estuary. For example, non-conservative behaviors were observed in the upper estuary, where nutrient elements may be remobilized due to the strong desorption and variations of the fresh water end-member, but conservative distributions were found afterwards in the lower estuary. Outside the riverine effluent plumes, nutrient elements may be depleted in surface waters relative to elevated bioproduction, whereas the regeneration with respect to decomposition of organic material and/or nitrification/denitrification offshore, may sustain high levels of nutrient elements in near-bottom waters. Laboratory experiment data generally compares well with field observations. The high fluxes and area] yields of nutrient elements from large Chinese rivers, indicate the extensive use of chemical fertilizers and domestic waste drainage over watersheds in China.

Zhang, Jing

1996-07-01

112

Signalling by amino acid nutrients.  

PubMed

It is clear that mTORC1 (mammalian target of rapamycin complex 1) is regulated by the presence of ambient amino acid nutrients. However, the mechanism by which amino acids regulate mTORC1 is still open to question, despite extensive efforts. Our recent work has revealed that PR61?, a B56 family regulatory subunit of PP2A (protein phosphatase 2A), associates with and regulates the activity of MAP4K3 (mitogen-activated protein kinase kinase kinase kinase 3), a protein kinase regulated by amino acid sufficiency that acts upstream of mTORC1. In searching for a physiological process regulated by amino acids, we have demonstrated recently that arginine plays a role in the activation of LPS (lipopolysaccharide)-induced MEK [MAPK (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) kinase]/ERK signalling in macrophages. PP2A similarly associates with the upstream regulator of MEK in this signalling pathway, TPL-2 (tumour progression locus-2), in response to arginine availability. Thus PP2A is a negative regulator of both MAP4K3 and TPL-2 in both mTORC1 and MEK/ERK signalling pathways. PMID:21428916

Yan, Lijun; Lamb, Richard F

2011-04-01

113

New actions for old nutrients.  

PubMed

The purpose of this review is to present information regarding new effects for certain nutrients other than those traditionally known. Zinc has been found to prevent and reduce the duration of common colds. In developing countries, zinc has been shown to reduce the duration and severity of diarrhea and even decrease relapses. Iron supplementation in iron deficient children, has been shown to improve several aspects of brain function. In studies where iron was given to the mother, 3 of 5 randomized, controlled trials showed a beneficial effect of iron supplementation on the Psychomotor Development Index at some time points, whereas 2 did not. The chances for infants supplemented with docosahexaenoic acid in the fi rst year of life of having at least 1 event of allergic manifestation or upper respiratory infection or at least 1 event of wheezing/asthma, wheezing/asthma/atopic dermatitis, any allergy, or an upper respiratory tract infection during the fi rst 3 years of life were significantly lower than in the non supplemented group. Epidemiological studies have established a relationship between low levels of serum vitamin D and reduced lung function in healthy adults and asthma onset and severity in children. There was a trend for an independent association between higher levels of maternal circulating 25(OH)D3 levels in pregnancy and decreased odds of lower respiratory tract infections in offspring. PMID:22493160

Lifschitz, Carlos

2012-04-01

114

Detecting temporal change in watershed nutrient yields.  

PubMed

Meta-analyses reveal that nutrient yields tend to be higher for watersheds dominated by anthropogenic uses (e.g., urban, agriculture) and lower for watersheds dominated by natural vegetation. One implication of this pattern is that loss of natural vegetation will produce increases in watershed nutrient yields. Yet, the same meta-analyses also reveal that, absent land-cover change, watershed nutrient yields vary from one year to the next due to many exogenous factors. The interacting effects of land cover and exogenous factors suggest nutrient yields should be treated as distributions, and the effect of land-cover change should be examined by looking for significant changes in the distributions. We compiled nutrient yield distributions from published data. The published data included watersheds with homogeneous land cover that typically reported two or more years of annual nutrient yields for the same watershed. These data were used to construct statistical models, and the models were used to estimate changes in the nutrient yield distributions as a result of land-cover change. Land-cover changes were derived from the National Land Cover Database (NLCD). Total nitrogen (TN) yield distributions increased significantly for 35 of 1550 watersheds and decreased significantly for 51. Total phosphorus (TP) yield distributions increased significantly for 142 watersheds and decreased significantly for 17. The amount of land-cover change required to produce significant shifts in nutrient yield distributions was not constant. Small land-cover changes led to significant shifts in nutrient yield distributions when watersheds were dominated by natural vegetation, whereas much larger land-cover changes were needed to produce significant shifts when watersheds were dominated by urban or agriculture. We discuss our results in the context of the Clean Water Act. PMID:18446405

Wickham, James D; Wade, Timothy G; Riitters, Kurt H

2008-08-01

115

Nutrient spiralling in streams: implications for nutrient limitation and invertebrate activity  

SciTech Connect

Nutrient cycling in streams occurs in conjunction with downstream transport as spatially distributed process that has been termed spiralling. The intensity of reutilization of nutrients as they pass downstream can be quantified in terms of the length of stream required for a nutrient atom to complete one (abstract) cycle; this distance is termed the spiralling length. The model for steady-state spiralling of a limiting nutrient predicts that most of the downstream transport of nutrient occurs in particulate or unavailable form when nutrient limitation is severe; in this case, transportability of particulates is a major determinant of spiralling length. On the other hand, when nutrient limitation is moderated by density-dependent mechanisms, transport in the dissolved phase dominates, and transportability of particles has little influence on spiralling length. The potential role of invertebrate consumers in controlling spiralling was investigated by considering their influence on regeneration, transportability, and uptake of nutrients. Functional processes of grazing and filter feeding appear most likely to shorten spiralling length when nutrient limitation is severe, while the process of shredding is more likely to shorten spiralling length when nutrient limitation is weak. In some cases there may be levels of consumer activity at which spiralling length is minimized.

Newbold, J.D.; O'Neill, R.V.; Elwood, J.W.; Van Winkle, W.

1982-11-01

116

Calibration models for electromagnetic induction methods to assess nutrient accumulation beneath confined livestock areas.  

PubMed

Nutrient accumulation in soils beneath confined livestock areas is a potential source of groundwater contamination. Electromagnetic induction (EMI) has become a practical method to assess nutrient content, with multiple linear regression (MLR) as the statistical method often employed to translate EMI readings into nutrient content. The purpose of this research is to compare and contrast the performance of spatially referenced MLR models that include secondary, 'easy-to-acquire' predictor variables such as spatial coordinate locations, soil water content and elevation information with MLR models based solely on EMI readings. Six feedlot areas were surveyed with an EM38 conductivity meter and between 6 and 12 sites at each feedlot were sampled at five different depths. The electrical conductivity (EC(e)), nitrate (NO3-) and phosphate (PO4(3-)) concentrations were measured and used as response variables. Analyses were performed using two different approaches: the response variables in individual layers and response variables by combining the layers within the soil profile. The results of both MLR methods were comparable in most instances because the models preferentially incorporated predictors derived from EM38 readings. Differences between the models were more evident when predicting NO3- and PO4(3-), even though prediction of these two analytes by either method was generally poor. Combined profile analysis was more effective for defining nutrient build-up because by-layer analysis gave non-significant or poor models in many instances. PMID:21473273

Cordeiro, Marcos R C; Ranjan, R Sri; Ferguson, Ian J

2011-01-01

117

Growth, aboveground biomass, and nutrient concentration of young Scots pine and lodgepole pine in oil shale post-mining landscapes in Estonia.  

PubMed

The investigation was carried out in 8-year-old Scots pine (Pinus sylvestris L.) and lodgepole pine (Pinus contorta var. latifolia Engelm.) plantations on post-mining area, Northeast Estonia. The aim of the study was to assess the suitability of lodgepole pine for restoration of degraded lands by comparing the growth, biomass, and nutrient concentration of studied species. The height growth of trees was greater in the Scots pine stand, but the tree aboveground biomass was slightly larger in the lodgepole pine stand. The aboveground biomass allocation to the compartments did not differ significantly between species. The vertical distribution of compartments showed that 43.2% of the Scots pine needles were located in the middle layer of the crown, while 58.5% of the lodgepole pine needles were in the lowest layer of the crown. The largest share of the shoots and stem of both species was allocated to the lowest layer of the crown. For both species, the highest NPK concentrations were found in the needles and the lowest in the stems. On the basis of the present study results, it can be concluded that the early growth of Scots pine and lodgepole pine on oil shale post-mining landscapes is similar. PMID:21374054

Kuznetsova, Tatjana; Tilk, Mari; Pärn, Henn; Lukjanova, Aljona; Mandre, Malle

2011-12-01

118

21 CFR 107.10 - Nutrient information.  

Code of Federal Regulations, 2013 CFR

...fluid ounces supplying 100 kilocalories (in case of food label statements, a kilocalorie is represented by the word âCalorieâ); and (2) A statement of the amount of each of the following nutrients supplied by 100 kilocalories:...

2013-04-01

119

Prevalence of nutrient deficiencies in bariatric patients  

Microsoft Academic Search

ObjectiveThe aims of this study were to determine the prevalence of nutrient deficiencies in patients who present for bariatric surgery, assess nutritional status after surgery, and compare these with preoperative levels.

Seok Yee Toh; Nazy Zarshenas; John Jorgensen

2009-01-01

120

Nutrient Requirements of Dairy Cattle (for Microcomputers).  

National Technical Information Service (NTIS)

The 'Nutrient Requirements of Dairy Cattle' computer program includes all requirements for energy, protein, calcium, phosphorus, and vitamins A and D. Dry matter intake and energy concentration assumptions have been made more consistent from table to tabl...

L. Browne

1988-01-01

121

NRMRL'S NUTRIENT-RELATED RISK MANAGEMENT RESEARCH  

EPA Science Inventory

Anthropogenic loadings of nutrients into our Nation's atmosphere, aquatic, and terrestrial ecosystems have increased dramatically within the past few decades. Environmental impairments associated with this over fertilization include aquatic habitat loss due to low dissolved oxyge...

122

Single Nutrient Effects on Immunological Functions.  

National Technical Information Service (NTIS)

Immune system dysfunction can result from single nutrient deficiencies or excesses, alone, or in combination with generalized protein-energy malnutrition. Acquired immune dysfunctions occur in man during deficiencies of iron, zinc, vitamins A and B12, pyr...

W. R. Beisel R. Edelman K. Nauss R. M. Suskind

1980-01-01

123

Biological Nutrient Removal Processes and Costs.  

National Technical Information Service (NTIS)

Nitrogen and phosphorus are the primary causes of cultural eutrophication (i.e., nutrient enrichment due to human activities) in surface waters. The most recognizable manifestations of this eutrophication are algal blooms that occur during the summer. Chr...

2007-01-01

124

USDA NATIONAL NUTRIENT DATABASE FOR STANDARD REFERENCE  

EPA Science Inventory

The USDA Nutrient Database for Standard Reference (SR) is the major source of food composition data in the United States. It provides the foundation for most food composition databases in the public and private sectors....

125

Guidelines for Safety Evaluation of Nutrients.  

National Technical Information Service (NTIS)

The report presents guidelines for evaluating potential adverse effects of ingesting high levels of nutrients as part of a comprehensive system for assessing safety. Comprehensive systems that have been developed for assessing the safety of environmental ...

R. G. Allison C. J. Carr T. C. Campbell

1980-01-01

126

NUTRIENTS IN WATERSHEDS: DEVELOPING ENHANCED MODELING TOOLS  

EPA Science Inventory

Nutrient enrichment is one of the most important stressors causing water-resource impairment. These impairments are causing devastating changes: 1) high nitrate concentrations have rendered the groundwaters and reservoirs in many regions impotable -- especially in the rural area...

127

Antioxidant nutrient intake and diabetic retinopathy  

Microsoft Academic Search

ObjectiveDiabetic retinopathy (DR) is a major cause of visual impairment and blindness in adults. Antioxidant nutrients, such as vitamins C and E and beta-carotene, may be protective of some eye disorders, such as cataract and age-related macular degeneration, but a relationship between these nutrients and DR has yet to be defined. The purpose of this study was to examine the

Elizabeth J Mayer-Davis; Ronny A Bell; Beth A Reboussin; Julia Rushing; Julie A Marshall; Richard F Hamman

1998-01-01

128

Microscale patchiness of nutrients in plankton communities.  

PubMed

Autoradiography was used to identify the presence of nutrient patches produced by zooplankton. Algal cells which encounter patches of phosphorus-33 released by swimming animals accumulate more label than cells that do not enter the patches. Differential labeling of algae does not occur when turbulence in the fluid is increased by stirring. Nutrient patchiness at the scale of millimeters or less in nature probably influences the course of competition and coexistence among the phytoplankton. PMID:17730135

Lehman, J T; Scavia, D

1982-05-14

129

A mathematical model of plant nutrient uptake  

Microsoft Academic Search

.   The classical model of plant root nutrient uptake due to Nye, Tinker and Barber is developed and extended. We provide an\\u000a explicit closed formula for the uptake by a single cylindrical root for all cases of practical interest by solving the absorption-diffusion\\u000a equation for the soil nutrient concentration asymptotically in the limit of large time. We then use this

T. Roose; A. C. Fowler; P. R. Darrah

2001-01-01

130

Nutrient budgets for large Chinese estuaries  

NASA Astrophysics Data System (ADS)

Chinese rivers deliver about 5-10% of global freshwater input and 15-20% of the global continental sediment to the world ocean. We report the riverine fluxes and concentrations of major nutrients (nitrogen, phosphorus, and silicon) in the rivers of the contiguous landmass of China and Korea in the northeast Asia. The rivers are generally enriched with dissolved inorganic nitrogen (DIN) and depleted in dissolved inorganic phosphate (PO43-) with very high DIN: PO43- concentration ratios. DIN, phosphorus, and silicon levels and loads in rivers are mainly affected by agriculture activities and urbanization, anthropogenic activities and adsorption on particulates, and rock types, climate and physical denudation intensity, respectively. Nutrient transports by rivers in the summer are 3-4 times higher than those in the winter with the exception of NH4+. The flux of NH4+ is rather constant throughout the year due to the anthropogenic sources such as the sewer discharge. As nutrient composition has changed in the rivers, ecosystems in estuaries and coastal sea have also changed in recent decades. Among the changes, a shift of limiting nutrients from phosphorus to nitrogen for phytoplankton production with urbanization is noticeable and in some areas silicon becomes the limiting nutrient for diatom productivity. A simple steady-state mass-balance box model was employed to assess nutrient budgets in the estuaries. The major Chinese estuaries export <15% of nitrogen, <6% of phosphorus required for phytoplankton production and ~4% of silicon required for diatom growth in the Chinese Seas (Bohai, Yellow Sea, East China Sea, South China Sea). This suggests that land-derived nutrients are largely confined to the immediate estuaries, and ecosystem in the coastal sea beyond the estuaries is mainly supported by other nutrient sources such as regeneration, open ocean and atmospheric deposition.

Liu, S. M.; Hong, G.-H.; Zhang, J.; Ye, X. W.; Jiang, X. L.

2009-10-01

131

Nutrient retention and nutrient-use efficiency in Phragmites australis stands after wasterwater application  

Microsoft Academic Search

The capacity of Phragmites australis to extract nutrients from its environment and to store them in plant tissue was studied in an infiltration wetland used for\\u000a wastewater treatment. The aims of the study were to estimate the contribution of plant uptake to the overall nutrient removal\\u000a efficiency of the wastewater treatment system and to determine measures to enhance the nutrient

Arthur F. M. Meuleman; Jos T. A. Verhoeven

2002-01-01

132

The stoichiometry of particulate nutrients in Lake Tanganyika – implications for nutrient limitation of phytoplankton  

Microsoft Academic Search

We studied the potential nutrient limitation of phytoplankton by means of seston nutrient stoichiometry and nutrient enrichment bioassays in the epilimnion of Lake Tanganyika. In most cases, the particulate carbon to phosphorus (C:P) ratio was high and indicated moderate P deficiency, while the respective C:N ratio mainly suggested moderate N deficiency. The N:P ratios of seston indicated rather balanced N

Marko Järvinen; Kalevi Salonen; Jouko Sarvala; Kristiina Vuorio; Anne Virtanen

1999-01-01

133

Nutrient fluxes from water to land: seabirds affect plant nutrient status on Gulf of California islands  

Microsoft Academic Search

Energy and nutrient fluxes across habitat boundaries can exert profound direct and indirect effects on the dynamics of recipient\\u000a systems. Transport from land to water is common and well studied; here, we document a less recognized process, substantial\\u000a flows from water to land. On hyperarid, naturally nutrient poor islands in the Gulf of California, nutrient input via seabird\\u000a guano directly

Wendy B. Anderson; Gary A. Polis

1999-01-01

134

Can Nutrient Spiralling be Used to Detect Seasonal Nutrient Uptake in A Forested Stream?  

Microsoft Academic Search

Nutrient spiralling measurements were conducted in Lyrebird Creek, a forested stream in the Dandenong Ranges, Victoria, Australia.\\u000a Spiralling indices from several nutrient (NH\\u000a 4\\u000a +\\u000a , PO\\u000a 4\\u000a 3?\\u000a ) enrichment experiments were correlated with seasonal variation in factors thought to control nutrient uptake, i.e., temperature,\\u000a light and algal biomass. It was hypothesized that nutrient uptake would be higher in

Sulfikar Hanafi; Michael R. Grace; Barry T. Hart

135

Contribution of Glomus intraradices inoculation to nutrient acquisition and mitigation of ionic imbalance in NaCl-stressed Trigonella foenum-graecum.  

PubMed

The study aimed to investigate the effects of an AM fungus (Glomus intraradices Schenck and Smith) on mineral acquisition in fenugreek (Trigonella foenum-graecum) plants under different levels of salinity. Mycorrhizal (M) and non-mycorrhizal (NM) fenugreek plants were subjected to four levels of NaCl salinity (0, 50, 100, and 200 mM NaCl). Plant tissues were analyzed for different mineral nutrients. Leaf senescence (chlorophyll concentration and membrane permeability) and lipid peroxidation were also assessed. Under salt stress, M plants showed better growth, lower leaf senescence, and decreased lipid peroxidation as compared to NM plants. Salt stress adversely affected root nodulation and uptake of NPK. This effect was attenuated in mycorrhizal plants. Presence of the AM fungus prevented excess uptake of Na(+) with increase in NaCl in the soil. It also imparted a regulatory effect on the translocation of Na(+) ions to shoots thereby maintaining lower Na(+) shoot:root ratios as compared to NM plants. Mycorrhizal colonization helped the host plant to overcome Na(+)-induced Ca(2+) and K(+) deficiencies. M plants maintained favorable K(+):Na(+), Ca(2+):Na(+), and Ca(2+):Mg(2+) ratios in their tissues. Concentrations of Cu, Fe, and Zn(2+) decreased with increase in intensity of salinity stress. However, at each NaCl level, M plants had higher concentration of Cu, Fe, Mn(2+), and Zn(2+) as compared to NM plants. M plants showed reduced electrolyte leakage in leaves as compared to NM plants. The study suggests that AM fungi contribute to alleviation of salt stress by mitigation of NaCl-induced ionic imbalance thus maintaining a favorable nutrient profile and integrity of the plasma membrane. PMID:21695577

Evelin, Heikham; Giri, Bhoopander; Kapoor, Rupam

2012-04-01

136

Grazing animal husbandry based on sustainable nutrient management  

Microsoft Academic Search

Sustainable husbandry systems for grazing animals (cattle and sheep) can be achieved by sustainable nutrient management (SNM). This implies the tuning of inputs to outputs of nutrients, to achieve and maintain optimum ranges of agronomically wanted and ecologically acceptable reserves of single nutrients in the soil. P is presented as the ‘boss cow of the nutrient herd’ and its optimum

C. Hermans; P. H. Vereijken

1995-01-01

137

A Comparison of Nutrient Density Scores for 100% Fruit Juices  

Microsoft Academic Search

The 2005 Dietary Guidelines for Americans recommend that consumers choose a variety of nutrient- dense foods. Nutrient density is usually defined as the quantity of nutrients per calorie. Food and nutrition profes- sionals should be aware of the concept of nutrient density, how it might be quantified, and its potential application in food labeling and dietary guidance. This article presents

G. C. Rampersaud

2007-01-01

138

Nutrient transporters in cancer: Relevance to Warburg hypothesis and beyond  

Microsoft Academic Search

Tumor cells have an increased demand for nutrients; this demand is met by increased availability of nutrients through vasculogenesis and by enhanced cellular entry of nutrients through upregulation of specific transporters. This review focuses on three groups of nutrient transporters relevant to cancer: glucose transporters, lactate transporters, and amino acid transporters. Tumor cells enhance glucose uptake via induction of GLUT1

Vadivel Ganapathy; Muthusamy Thangaraju; Puttur D. Prasad

2009-01-01

139

Adapting a CAFO's NMP for Today's Nutrient Challenges  

Microsoft Academic Search

Are nutrient planning processes adapting to our changing knowledge of nutrient issues on animal feeding operations? Our current public policy focuses nutrient planning procedures on efficient recycling of manure nutrients within the boundaries of an animal feeding operation's property. While this approach is an important step towards achieving sustainable animal feeding operations, it may not be the final solution for

Rick Koelsch

140

Marine nutrient contributions to tidal creeks in Virginia: spawning marine fish as nutrient vectors to freshwater ecosystems  

Microsoft Academic Search

Coastal freshwater streams are typically viewed as conduits for the transport of sediment and nutrients to the coasts. Some coastal streams however experience seasonal migrations of anadromous fish returning to the freshwater to spawn. The fish may be vectors for the delivery of marine nutrients to nutrient poor freshwater in the form of excreted waste and post-spawning carcasses. Nutrients derived

S. E. Macavoy; G. C. Garman

2006-01-01

141

Relationship between nutrient concentration, phytoplankton density, and zooplankton density in nutrient enriched experimental ponds  

Microsoft Academic Search

The effects of different levels of nutrient input on the plankton community was investigated in a two-year controlled fertilization study of eight experimental ponds. There were four treatments, each replicated: a control, to which no fertilizer was added, and three levels of nutrient addition. Limnological parameters including phytoplankton and zooplankton densities were measured frequently during both summers and less frequently

W. John O'Brien; Frank Noyelles

1974-01-01

142

Spatiotemporal patterns in nutrient loads, nutrient concentrations, and algal biomass in Lake Taihu, China  

Microsoft Academic Search

Lake Taihu, China's third largest freshwater lake, exemplifies the severity of eutrophication problems in rapidly developing regions. We used long term land use, water quality, and hydrologic data from 26 in-lake and 32 tributary locations to describe the spatiotemporal patterns in nutrient loads, nutrient concentration, algal biomass, measured as chlorophyll a (Chl-a), in Lake Taihu. Point and nonpoint sources, as

Yiping Li; Kumud Acharya; Mark C. Stone; Zhongbo Yu; Michael H. Young; David S. Shafer; Jianting Zhu; Karen Gray; Asako Stone; Lili Fan; Chunyan Tang; John Warwick

2011-01-01

143

Automated management of nutrient solutions based on target electrical conductivity, ph, and nutrient concentration ratios  

Microsoft Academic Search

An algorithm to automatically formulate the composition and prepare nutrient solutions for soilless cultures based on desired characteristics given as target values is proposed. To formulate the complete ionic composition of a nutrient solution, standard recommendations referring to the following solution characteristics should be available: (i) electrical conductivity (EC), (ii) pH, (iii) concentration ratios of macronutrients (meq basis), and (iv)

Dimitrios Savvas; Konstantinos Adamidis

1999-01-01

144

Nutrient Requirements of Domestic Animals, Number 10: Nutrient Requirements of Laboratory Animals. Third Revised Edition, 1978.  

ERIC Educational Resources Information Center

This report deals with the nutrient requirements of seven species of animals used extensively for biomedical research in the United States. Following an introductory chapter of general information on nutrition, chapters are presented on the nutrient requirements of the laboratory rat, mouse, gerbil, guinea pig, hamster, vole, and fishes. Each…

National Academy of Sciences - National Research Council, Washington, DC. Board on Agricultural and Renewable Resources.

145

Quality control procedures for the USDA Food and Nutrient Database for Dietary Studies nutrient values  

Microsoft Academic Search

Accurate dietary assessment depends on a high-quality food and nutrient database. While much progress has been made in the quality of analytical nutrient data, the area of database quality control remains largely uncovered. Increased automation of database maintenance and update processes necessitates stringent quality control procedures. A detailed quality control (QC) plan has advanced over the years and is in

Jaspreet K. C. Ahuja; Betty P. Perloff

2008-01-01

146

Extrapolating Ambient Nutrient Uptake From Multiple Nutrient Amendments: A Method Evaluation  

NASA Astrophysics Data System (ADS)

Nutrient dynamics in streams are often quantified with short-term nutrient amendments that elevate stream water nutrient concentration. However, elevating nutrient concentration can alter nutrient uptake from ambient conditions. Previous studies have documented that the relationship between nutrient concentration and uptake follows Michaelis-Menten kinetics and that ambient uptake length can be estimated by extrapolation from a series of increasing nutrient amendments. We tested this approach in five streams spanning a gradient of nitrate concentration. We used an isotope tracer (15NO3-N) to quantify the ambient uptake length (Sw). We compared Sw to the uptake length determined by a single nitrate amendment and to the uptake length extrapolated from a series of amendments in which nitrate concentration was incrementally elevated. Extrapolated ambient uptake length was a better predictor of Sw than single amendment-derived uptake length in three streams. Extrapolated ambient uptake length was negative in two streams with high background nitrate concentrations. Our data suggest that nitrogen limitation was weak in these two streams and that the relationship between nitrate concentration and uptake deviated from Michaelis-Menten kinetics. The extrapolation technique proved to be a useful method; however, this approach may be less effective in streams where the studied nutrient is not limited.

Earl, S. R.; Payn, R. A.; Valett, H. M.; Webster, J. R.

2005-05-01

147

Microbial life at extremely low nutrient levels.  

PubMed

Many microorganisms ("oligotrophs") grow in distilled water: Pseudomonas spp., Caulobacter spp., Hyphomicrobium spp., Arthrobacter spp., Seliberia spp., Bactoderma alba, Corynebacterium spp., Amycolata (Nocardia) autotrophica, Mycobacterium spp., yeasts, and Chlorella spp. Also, certain lower fungi can be found here. In the laboratory, these organisms thrive on contaminations of the air (CO, hydrocarbons, H2, alcohols etc.). All are euryosmotic and often grow also in higher concentrations of salts and nutrients. Natural locations with extremely low nutrient levels (snow, rain water pools, springs, free ocean water, Antarctic rocks and soils) do not contain more than 1-5 mg/l of organic carbon. Oligotrophs found here are especially adapted to constant famine: they frequently live attached to surfaces, form polymers and storage products even while starving, and often aggregate. Many of these oligotrophs alter their morphology (surface to volume ratio) with changing nutrient concentrations. Extreme oligotrophs also occur in generally nutrient-rich environments such as sewage aeration tanks or compost soil. Here they are thought to survive in nutrient-depauperate microhabitats. PMID:11537832

Hirsch, P

1986-01-01

148

Microbial life at extremely low nutrient levels  

NASA Astrophysics Data System (ADS)

Many microorganisms (``oligotrophs'') grow in distilled water: Pseudomonas spp., Caulobacter spp., Hyphomicrobium spp., Arthrobacter spp., Seliberia spp., Bactoderma alba, Corynebacterium spp., Amycolata (Nocardia) autotrophica, Mycobacterium spp., yeasts, and Chlorella spp. Also, certain lower fungi can be found here. In the laboratory, these organisms thrive on contaminations of the air (CO, hydrocarbons, H2, alcohols etc.). All are euryosmotic and often grow also in higher concentrations of salts and nutrients. Natural locations with extremely low nutrient levels (snow, rain water pools, springs, free ocean water, Antarctic rocks and soils) do not contain more than 1-5 mg/1 of organic carbon. Oligotrophs found here are especially adapted to constant famine: they frequently live attached to surfaces, form polymers and storage products even while starving, and often aggregate. Many of these oligotrophs alter their morphology (surface to volume ratio) with changing nutrient concentrations. Extreme oligotrophs also occur in generally nutrient-rich environments such as sewage aeration tanks or compost soil. Here they are thought to survive in nutrient-depauperate microhabitats.

Hirsch, P.

149

Nutrients affecting brain composition and behavior  

NASA Technical Reports Server (NTRS)

This review examines the changes in brain composition and in various brain functions, including behavior, that can follow the ingestion of particular foods or nutrients. It details those that are best understood: the increases in serotonin, catecholamine, or acetylcholine synthesis that can occur subsequent to food-induced increases in brain levels of tryptophan, tyrosine, or choline; it also discusses the various processes that must intervene between the mouth and the synapse, so to speak, in order for a nutrient to affect neurotransmission, and it speculates as to additional brain chemicals that may ultimately be found to be affected by changes in the availability of their nutrient precursors. Because the brain chemicals best known to be nutrient dependent overlap with those thought to underlie the actions of most of the drugs used to treat psychiatric diseases, knowledge of this dependence may help the psychiatrist to understand some of the pathologic processes occurring in his/her patients, particularly those with appetitive symptoms. At the very least, such knowledge should provide the psychiatrist with objective criteria for judging when to take seriously assertions that particular foods or nutrients do indeed affect behavior (e.g., in hyperactive children). If the food can be shown to alter neurotransmitter release, it may be behaviorally-active; however, if it lacks a discernible neurochemical effect, the likelihood that it really alters behavior is small.

Wurtman, R. J.

1987-01-01

150

Nutrient transporters: the Achilles' heel of anabolism  

PubMed Central

Highly proliferative cells, including cancer cells, require a constant supply of molecular building blocks to support their growth. To acquire substrates such as glucose and amino acids from the extracellular space, dividing cells rely on transporter proteins in the plasma membrane. Numerous studies link transcriptional and post-translational control of nutrient transporter expression with proliferation, highlighting the importance of nutrient transporters in both physiologic and pathologic growth. Here we review recent work that spotlights the crucial role of nutrient transporters in cell growth and proliferation, discuss post-translational mechanisms for coordinating expression of different transporters, and consider the therapeutic potential of targeting these proteins in cancer and other diseases characterized by inappropriate cell division.

McCracken, Alison N.; Edinger, Aimee L.

2013-01-01

151

Insulin sensitivity: modulation by nutrients and inflammation  

PubMed Central

Insulin resistance is a major metabolic feature of obesity and is a key factor in the etiology of a number of diseases, including type 2 diabetes. In this review, we discuss potential mechanisms by which brief nutrient excess and obesity lead to insulin resistance and propose that these mechanisms of action are different but interrelated. We discuss how pathways that “sense” nutrients within skeletal muscle are readily able to regulate insulin action. We then discuss how obesity leads to insulin resistance via a complex interplay among systemic fatty acid excess, microhypoxia in adipose tissue, ER stress, and inflammation. In particular, we focus on the hypothesis that the macrophage is an important cell type in the propagation of inflammation and induction of insulin resistance in obesity. Overall, we provide our integrative perspective regarding how nutrients and obesity interact to regulate insulin sensitivity.

Schenk, Simon; Saberi, Maziyar; Olefsky, Jerrold M.

2008-01-01

152

Exergy analysis of nutrient recovery processes.  

PubMed

In an exergy analysis, the actual consumption of resources in physical and chemical processes is calculated. Energy and chemical elements are not consumed in the processes--they are only transformed into other forms with lower quality. The principals of exergy analysis are illustrated by comparing different wastewater treatment systems for nutrient recovery. One system represents an end-of-pipe structure, whereas other systems include source separation of grey water, black water, and urine. The exergy flows analysed in this paper are those related to management and treatment of organic matter and nutrients. The study shows that the total exergy consumption is lowest for the system with source separation of urine and faeces and greatest for the conventional wastewater treatment system complemented by processes for nutrient recovery. PMID:12926618

Hellström, D

2003-01-01

153

Variations in concentrations and fluxes of dissolved inorganic nutrients related to catchment scale human interventions in Pamba River, Kerala, India  

NASA Astrophysics Data System (ADS)

River basins are geo-hydrological units. Water flowing out of the basin bears the imprint of natural factors such as geology, soil, vegetation and rainfall along with anthropogenic factors including the type and degree of human intervention within the basin. Pamba, a small mountainous river in the SW coast of India with a population density of ~1,400 persons km-2 was studied for its varying land use and human interventions as the global database are biased towards temperate regions while little is know about the smaller catchments from tropical regions. Land use comprised of dense forest in the highland region together with forest plantation and the human impacted Sabarimala temple- the second largest pilgrim, settlement with mixed tree crop (smt) in the midland and lowland paddy cultivated region. 50-60 million devotees visiting Sabarimala during November to January every year associated with the ritual bathing, discharge of human wastes emanating from the influx of millions of pilgrims due to inadequate number of sanitary latrines and the lack of facilities for sewage collection and treatment caused several ecological variations during pilgrim season. In order to asses the effect of land use and pilgrims in combination with seasonal variations in hydrology we investigated the seasonal and spatial variations in physicochemical and nutrient concentrations. Samples were collected from March 2010 to February 2012 during premonsoon (January-May), SW(June to September) and NE monsoon(October to December), from sites varying in land use. Nutrient budgets (load and yield) were calculated to quantify the inputs from various land use segments. Spatio-temporal variations in the physicochemical and dissolved nutrient concentrations were observed along the course of the river. Upstream forest region had highest dissolved oxygen(DO) and pH together with lowest dissolved inorganic nitrogen(DIN) values indicating almost pristine conditions. DIN in the temple region had the maximum value during the pre and NE monsoon. Highest DIN with ammonium(NH4+) as the major component in January were observed during the peak pilgrim season. Except for the temple locations NH4+ values were low in the rest of the catchment. Nitrate(NO3-) was dominant during SW monsoon in the midland and low land regions due to the various agricultural practices displaying variability along the course of the river. Maximum values for phosphate (PO43-) and silicate (Si(OH)4) were in the temple area during the premonsoon months. Average NPK fertilizer use in the basin was 80.2 kg ha-1.When compared to the average of all India (72 kg.ha-1) usage is high but lower than Western Europe and U.S (250 kg.ha-1).Yield calculated were 7186.6 kg km-2yr-1for DIN, 453.2 kg km-2yr-1for PO43--P and 17728.9 kg km-2yr- for dissolved Si. NH4+-N and dissolved Si yield were maximum in the temple and forest dominated regions, NO3--N and PO43--P in smt regions respectively. When compared to other tropical rivers, nutrient yield from the Pamba River found to be higher points to the significant hydrological and land use practices. To conclude, land use activities in the basin are the key factor contributing to varying water quality and nutrient concentrations and loading in the Pamba catchment the main being pilgrim event and agriculture in our study.

David, S. E.; Jennerjahn, T. C.; Chattopadhyay, S.

2012-12-01

154

Export of nutrients from the Arctic Ocean  

NASA Astrophysics Data System (ADS)

study provides the first physically based mass-balanced transport estimates of dissolved inorganic nutrients (nitrate, phosphate, and silicate) for the Arctic Ocean. Using an inverse model-generated velocity field in combination with a quasi-synoptic assemblage of hydrographic and hydrochemical data, we quantify nutrient transports across the main Arctic Ocean gateways: Davis Strait, Fram Strait, the Barents Sea Opening (BSO), and Bering Strait. We found that the major exports of all three nutrients occur via Davis Strait. Transports associated with the East Greenland Current are almost balanced by transports associated with the West Spitsbergen Current. The most important imports of nitrate and phosphate to the Arctic occur via the BSO, and the most important import of silicate occurs via Bering Strait. Oceanic budgets show that statistically robust net silicate and phosphate exports exist, while the net nitrate flux is zero, within the uncertainty limits. The Arctic Ocean is a net exporter of silicate (-15.7 ± 3.2 kmol s-1) and phosphate (-1.0 ± 0.3 kmol s-1; net ± 1 standard error) to the North Atlantic. The export of excess phosphate (relative to nitrate) from the Arctic, calculated at -1.1 ± 0.3 kmol s-1, is almost twice as large as previously estimated. Net transports of silicate and phosphate from the Arctic Ocean provide 12% and 90%, respectively, of the net southward fluxes estimated at 47°N in the North Atlantic. Additional sources of nutrients that may offset nutrient imbalances are explored, and the relevance and the pathway of nutrient transports to the North Atlantic are discussed.

Torres-Valdés, Sinhué; Tsubouchi, Takamasa; Bacon, Sheldon; Naveira-Garabato, Alberto C.; Sanders, Richards; McLaughlin, Fiona A.; Petrie, Brian; Kattner, Gerhard; Azetsu-Scott, Kumiko; Whitledge, Terry E.

2013-04-01

155

Mapping Nutrients Crucial to a Growing Population  

NASA Astrophysics Data System (ADS)

Over two billion people worldwide suffer from inadequate levels of micronutrients, mainly in the form of iodine, iron, and vitamin A deficiencies. With a growing population, producing crops that contain high amounts of these micronutrients is of increased importance. Addressing these deficiencies sustainably requires a detailed examination of the agricultural production of the micronutrients. The purpose of this study is to determine whether or not enough of these important nutrients are produced to meet the nutritional needs of the global population, and to determine where nutrients are most deficient. We used area specific crop production data to map where and how much iron and vitamin A are produced from major crops.

Tarnowski, J. R.; Cassidy, E. S.; Gerber, J. S.

2011-12-01

156

Nutrient management, food and the environment  

SciTech Connect

TVA's fertilizer programs were a key in America's agricultural revolution. Its re-oriented programs will be a key in maintaining the capabilities of our agricultural industry[emdash]safely. The nutrient management programs of TVA are distinctive. They complement what others are doing. TVA is extremely effective in technology transfer, launching innovative programs, targeting problem areas, and producing and implementing results that are practical. TVA's success in plant nutrient development and management reflects not only the scientific and engineering expertise of its own staff but also its flexibility and capability for working across boundaries that may be perceived as barriers by others.

Not Available

1992-04-01

157

Nutrient management, food and the environment  

SciTech Connect

TVA`s fertilizer programs were a key in America`s agricultural revolution. Its re-oriented programs will be a key in maintaining the capabilities of our agricultural industry{emdash}safely. The nutrient management programs of TVA are distinctive. They complement what others are doing. TVA is extremely effective in technology transfer, launching innovative programs, targeting problem areas, and producing and implementing results that are practical. TVA`s success in plant nutrient development and management reflects not only the scientific and engineering expertise of its own staff but also its flexibility and capability for working across boundaries that may be perceived as barriers by others.

Not Available

1992-04-01

158

Efect of organic barley-based crop rotations on soil nutrient balance in a semiarid environment for a 16-year experiment  

NASA Astrophysics Data System (ADS)

In natural ecosystems with no percolating moisture regime, the biogeochemical cycle can be considered a closed system because the nutrients extracted by the roots will be returned to the soil after a certain time. In organic farming, a cycle model as close as possible is taken as a guideline, but we have to consider that unlike natural ecosystems, where most of the nutrients remain in the cycle, the agrosystems are open cycles. To achieve a sustainable fertility of the soil, the soil nutrient levels, the extractions according to the expected crop yields and the export refunds in the form of crop residues, biological nitrogen fixation, green manure or compost will have to be determined. Nutrient balance should be closed with external inputs, always avoiding to be a source of negative impacts on the environment. In organic farming without exogenous inputs, the effect of the crop rotations is much more noticeable in the nutrient balance than in the conventional farming fields which every year receive inputs of nutrients (nitrogen, phosphorus and potassium) in the form of chemical fertilizers. The most extractive crop rotations are those that produce a greater decrease in soil reserves, and in these cases exogenous inputs to maintain sustainability should be considered; however, in less extractive crop rotations, extractions can be restored by the edaphogenesis processes. In this work, soil organic matter, phosphorus and potassium balances were analyzed in different organic barley-based crop rotations (barley monoculture [b-b] and in rotation with vetch for hay production [B-Vh], vetch as green manure [B-Vm], sunflower [B-S], chickpea [B-C] and fallow [B-F]) in clay soils under a semiarid environment ("La Higueruela" Experimental Farm, Santa Olalla, Toledo, central Spain) over a 16 year period. Additionally, barley monoculture in conventional farming [B-B] was included. In the organic system, the fertilization involved the barley straw in all rotations, the sunflower straw in B-S, the symbiotic nitrogen from the vetch crops and the green manure in B-Vm. In the conventional system, fertilization consisted on barley straw and chemical fertilizers at a rate of 80-60-30 kg N-P-K ha-1. Before the organic management, the whole plot was subjected to conventional practices. The highest total yields (and therefore the nutrients extractions) were obtained in B-Vh, followed in this order by B-B, B-S, B-F, B-Vm, B-C and b-b. The crop rotations with the highest yields favoured the microbial activity and the organic residues mineralization, although this caused, eventually, a small decrease in the soil organic matter content. Since the eighth year, this parameter remained more stable until the end of the study period. The highest decrease of soil organic matter took place in B-F and B-S, while the lowest ones happened in B-B, where the great amounts of barley straw incorporated into the soil compensated the organic matter losses. The conversion from conventional to organic management with the incorporation of the straw to the soil implies a re-adaptation process with a decrease of the soil phosphorus level by the increasing soil microbial biomass. A decrease of phosphorus during the first six years of the experiment and a posterior recovery and stabilization of this ratio by the solubilisation of the fixed phosphorus was observed. B-F and B-S presented the lowest soluble phosphorus losses, while B-C the highest ones. In the same way, the potassium level decreased during the first eight years and after that remained constant. The highest decreases took place in the rotations with the biggest amounts of barley straw; this decrease could be explained by the nutrient immobilization caused by the microbial biomass.

Meco, Ramón; María Moreno, Marta; Lacasta, Carlos; Moreno, Carmen

2013-04-01

159

Fast Detection of Nutrient Limitation in Macroalgae and Seagrass with Nutrient-Induced Fluorescence  

PubMed Central

Background Rapid determination of which nutrients limit the primary production of macroalgae and seagrasses is vital for understanding the impacts of eutrophication on marine and freshwater ecosystems. However, current methods to assess nutrient limitation are often cumbersome and time consuming. For phytoplankton, a rapid method has been described based on short-term changes in chlorophyll fluorescence upon nutrient addition, also known as Nutrient-Induced Fluorescence Transients (NIFTs). Thus far, though, the NIFT technique was not well suited for macroalgae and seagrasses. Methodology & Principal Findings We developed a new experimental setup so that the NIFT technique can be used to assess nutrient limitation of benthic macroalgae and seagrasses. We first tested the applicability of the technique on sea lettuce (Ulva lactuca) cultured in the laboratory on nutrient-enriched medium without either nitrogen or phosphorus. Addition of the limiting nutrient resulted in a characteristic change in the fluorescence signal, whereas addition of non-limiting nutrients did not yield a response. Next, we applied the NIFT technique to field samples of the encrusting fan-leaf alga Lobophora variegata, one of the key algal species often involved in the degradation of coral reef ecosystems. The results pointed at co-limitation of L. variegata by phosphorus and nitrogen, although it responded more strongly to phosphate than to nitrate and ammonium addition. For turtle grass (Thalassia testudinum) we found the opposite result, with a stronger NIFT response to nitrate and ammonium than to phosphate. Conclusions & Significance Our extension of the NIFT technique offers an easy and fast method (30–60 min per sample) to determine nutrient limitation of macroalgae and seagrasses. We successfully applied this technique to macroalgae on coral reef ecosystems and to seagrass in a tropical inner bay, and foresee wider application to other aquatic plants, and to other marine and freshwater ecosystems.

den Haan, Joost; Huisman, Jef; Dekker, Friso; ten Brinke, Jacomina L.; Ford, Amanda K.; van Ooijen, Jan; van Duyl, Fleur C.; Vermeij, Mark J. A.; Visser, Petra M.

2013-01-01

160

Nutrient and chemical sensing by intestinal pathogens.  

PubMed

Pathogenic gut bacteria, such as those comprising the Enterobacteriaceae family, have evolved sophisticated virulence mechanisms, including nutrient and chemical sensing, to escape host defense strategies and produce disease. In this review we describe the mechanisms utilized by the enteric pathogen enterohemorrhagic Escherichia coli (EHEC) O157:H7 to achieve successful colonization of its mammalian host. PMID:23850657

Hernandez-Doria, Juan D; Sperandio, Vanessa

2013-11-01

161

MIDDLE SNAKE RIVER PRODUCTIVITY AND NUTRIENT ASSESSMENT  

EPA Science Inventory

From 1992 to 1994, the University of Idaho conducted a research project on the water quality- limited section of the MIddle Snake River from Twin Falls downstream to Upper Salmon Falls Dam in an effort to determine the relationship between the nutrients and sediments entering thi...

162

Revised U.S. nutrient management standard  

NASA Astrophysics Data System (ADS)

A newly revised National Nutrient Management Standard could have "a continental impact on how we use nutrients" on potentially hundreds of millions of acres of farmland in the United States, Dave White, chief of the U.S. Department of Agriculture's Natural Resources Conservation Service (USDA/NRCS), said at a 13 December news briefing. NRCS uses the voluntary standard, which was last updated in 2006, to help producers better manage the application of nutrients—including fertilizers, animal manures, legumes, and crop cover—on agricultural land. Proper application of nitrogen and phosphorous is of particular concern, White said, adding that the new standard has an increased emphasis on the "four R's" of nutrient management: using the right amount of fertilizer and the right source, and applying the fertilizer in the right place at the right time. In addition, he said, the new standard emphasizes a number of technological tools for fertilizer and farmland management that have become available since the last update of the standards.

Showstack, Randy

163

ATMOSPHERIC DEPOSITION MODELING AND MONITORING OF NUTRIENTS  

EPA Science Inventory

This talk presents an overview of the capabilities and roles that regional atmospheric deposition models can play with respect to multi-media environmental problems. The focus is on nutrient deposition (nitrogen). Atmospheric deposition of nitrogen is an important contributor to...

164

Can Nutrients in Water Cause Harm?  

NSDL National Science Digital Library

In this water pollution activity, learners create pond water cultures and investigate the effects of adding chemicals or natural nutrients. Learners investigate, on a small scale, the changes that occur when fertilizers are added to pond water cultures over the course of a few days. This lesson guide includes background information, variations and bilingual (English/Spanish) handouts.

Moreno, Nancy P.; Tharp, Barbara Z.; Dresden, Judith H.

2010-01-01

165

Energy flow, nutrient cycling, and ecosystem resilience  

Microsoft Academic Search

The resilience, defined here as the speed with which a system returns to equilibrium state following a perturbation, is investigated for both food web energy models and nutrient cycling models. Previous simulation studies of food web energy models have shown that resilience increases as the flux of energy through the food web per unit amount of energy in the steady

DeAngelis

1980-01-01

166

Effects of Nutrients on Spring Ecosystems  

Microsoft Academic Search

Summary The relationship between nutrients and spring ecosystem structure and function primarily focuses on the state-wide increase in spring nitrate concentrations derived from anthropogenic sources and the concurrent observed visual decline of these ecosystems. However, the apparent correlation between increased nitrate loading and declining aesthetic appearance of spring ecosystems has only anecdotally provided evidence for a causative relationship. Organism-level studies,

Robert L. Knight; Sky K. Notestein

167

Can nutrient loads predict marine water quality?  

NSDL National Science Digital Library

This American Chemical Society article explores whether phosphorous or nitrogen plays a larger role in creating the algal blooms of the Mississippi River dead zone. It documents results of a study that finds that the algae-nutrient interaction is complex, but that the system is more phosphorous limited upstream and becomes more nitrogen limited farther downstream.

Pelley, Janet; Society, American C.

168

Uncertainty Propagation in an Ecosystem Nutrient Budget.  

EPA Science Inventory

New aspects and advancements in classical uncertainty propagation methods were used to develop a nutrient budget with associated error for a northern Gulf of Mexico coastal embayment. Uncertainty was calculated for budget terms by propagating the standard error and degrees of fr...

169

Modelling Nutrient Uptake of Sweet Pepper  

Microsoft Academic Search

Models simulating dry matter production have been developed for a large number of greenhouse crops during the past decades. This paper describes how plant-nutrient relationships can be incorporated in a model for greenhouse crops, with sweet pepper as an example. Based on climatic data, the model simulates the growth of plant organs, transpiration, water uptake and uptake of the various

L. F. M. Marcelis; E. Brajeul; A. Elings; A. Garate; E. Heuvelink

2005-01-01

170

Biological Nutrient Removal in Compact Biofilm Systems  

Microsoft Academic Search

The removal of nutrients such as nitrogen and phosphorus from both domestic and industrial wastewaters is imperative since they potentially harm the environment. One of the main consequences of excessive availability of nitrogen and phosphorus in aquatic ecosystems (freshwater, marine and estuarine) is the overgrowth of algae and other aquatic plants, a phenomenon designated as eutrophication. Algae and aquatic plants

J. P. Bassin

2012-01-01

171

Nutrient sensing and inflammation in metabolic diseases  

Microsoft Academic Search

The proper functioning of the pathways that are involved in the sensing and management of nutrients is central to metabolic homeostasis and is therefore among the most fundamental requirements for survival. Metabolic systems are integrated with pathogen-sensing and immune responses, and these pathways are evolutionarily conserved. This close functional and molecular integration of the immune and metabolic systems is emerging

Ebru Erbay; Gökhan S. Hotamisligil

2008-01-01

172

Eelgrass recovery after nutrient enrichment reversal  

Microsoft Academic Search

Mumford Cove, a 48ha Connecticut embayment on Long Island Sound, has a history of excessive nutrient inputs and corresponding eutrophic conditions with concomitant eelgrass (Zostera marina L.) loss. From 1945 to 1987, a municipal wastewater treatment facility discharged into the cove. In 1987, when the wastewater outfall was diverted to another location, the cove supported a near monoculture of the

Jamie M. P. Vaudrey; James N. Kremer; Brett F. Branco; Frederick T. Short

2010-01-01

173

Nutritional survey in Greek children: nutrient intake  

Microsoft Academic Search

The aim of the survey was to record the food habits and nutrient intake of Greek children. Data was obtained by a 3 d household measured diet record from a random stratified sample (1936 children aged 2–14 y). Mean daily protein intake was much higher than PRI and none of the children had lower intake than AR. Mean energy intake

E Roma-Giannikou; D Adamidis; M Gianniou; R Nikolara; N Matsaniotis

1997-01-01

174

Recapturing nutrients from dairy waste using biochar  

NASA Astrophysics Data System (ADS)

Biochar or biomass derived black carbon is known to be highly resistant to decomposition with half-life periods ranging from hundreds of years to millennia. It is also reported to enhance soil productivity due to high nutrient retention and favorable effects on soil pH, water retention capacity as well as microbial population. Brazilian Terra Preta soils have shown the potential of biochar for long-term carbon sequestration capacity and productivity of soil and many researchers have now focused on utilizing this phenomenon to create fertile, carbon-rich soils, called Terra Preta Nova. Although the highly adsorptive nature of biochar is well characterized, the potential for using biochar in environmental cleanup efforts is relatively unexplored. Dairy waste is a source of significant water pollution because it introduces excess nutrients such as phosphates and nitrates into the soil and water system. Since many soils have limited capacity to retain nitrate and phosphate, especially for long periods of time, the utility of dairy waste manure to enhance soil fertility and nutrient availability to plants is limited. Here, we present results from a project that we started to determine the potential of biochar to recover the excess nutrients from dairy flushed manure. In this initial study, a commercially available biochar amendment was ground and used in a batch sorption experiment with the dairy flushed manure from a local dairy in Merced, California. Four manure dilutions viz. 10, 25, 50 and 100%, and three shaking times, viz. 1, 12 and 24 hours were used for this study. We then calculated the amount of ammonia, nitrate and phosphate adsorbed by the biochar using differences in nutrient concentrations before and after the sorption experiment. Biochar showed significant capacity of adsorbing these nutrients, suggesting a potential for controlling the dairy pollution. The resulting enriched biochar can potentially act as a slow release fertilizer and enhance soil productivity as well as increasing the long-term carbon sequestration potential of soils. We are currently initiating further research to determine the desorption potenial of the biochar sorbed nutrients in soil.

Sarkhot, D.; Ghezzehei, T. A.; Berhe, A. A.

2009-12-01

175

Nutrient Status of Adults with Cystic Fibrosis  

PubMed Central

Nutrition is thought to influence disease status in patients with cystic fibrosis (CF). This cross-sectional study sought to evaluate nutrient intake and anthropometric data from 64 adult outpatients with cystic fibrosis. Nutrient intake from food and supplements was compared with the Dietary Reference Intakes for 16 nutrients and outcomes influenced by nutritional status. Attention was given to vitamin D and calcium given potential skeletal implications due to cystic fibrosis. Measurements included weight, height, body composition, pulmonary function, and serum metabolic parameters. Participants were interviewed about dietary intake, supplement use, pulmonary function, sunlight exposure, and pain. The participants’ mean body mass index (±standard deviation) was 21.8±4.9 and pulmonary function tests were normal. Seventy-eight percent used pancreatic enzyme replacement for malabsorption. Vitamin D deficiency [25-hydroxyvitamin D (25OHD)<37.5 nmol/L] was common: 25 (39%) were deficient despite adequate vitamin D intake. Lipid profiles were normal in the majority, even though total and saturated fat consumption represented 33.0% and 16.8% of energy intake, respectively. Reported protein intake represented 16.9% of total energy intake (range 10%–25%). For several nutrients, including vitamin D and calcium, intake from food and supplements in many participants exceeded recommended Tolerable Upper Intake Levels. Among adults with cystic fibrosis, vitamin D deficiency was common despite reported adequate intake, and lipid profiles were normal despite a relatively high fat intake. Mean protein consumption was adequate, but the range of intake was concerning, as both inadequate or excessive intake may have deleterious skeletal effects. These findings call into question the applicability of established nutrient thresholds for patients with cystic fibrosis.

GORDON, CATHERINE M.; ANDERSON, ELLEN J.; HERLYN, KAREN; HUBBARD, JANE L.; PIZZO, ANGELA; GELBARD, RONDI; LAPEY, ALLEN; MERKEL, PETER A.

2011-01-01

176

Nutrient-substituted hydroxyapatites: synthesis and characterization  

NASA Technical Reports Server (NTRS)

Incorporation of Mg, S, and plant-essential micronutrients into the structure of synthetic hydroxyapatite (HA) may be advantageous for closed-loop systems, such as will be required on Lunar and Martian outposts, because these apatites can be used as slow-release fertilizers. Our objective was to synthesize HA with Ca, P, Mg, S, Fe, Cu, Mn, Zn, Mo, B, and Cl incorporated into the structure, i.e., nutrient-substituted apatites. Hydroxyapatite, carbonate hydroxyapatite (CHA), nutrient-substituted hydroxyapatite (NHA), and nutrient-substituted carbonate hydroxyapatite (NCHA) were synthesized by precipitating from solution. Chemical and mineralogical analysis of precipitated samples indicated a considerable fraction of the added cations were incorporated into HA, without mineral impurities. Particle size of the HA was in the 1 to 40 nm range, and decreased with increased substitution of nutrient elements. The particle shape of HA was elongated in the c-direction in unsubstituted HA and NHA but more spherical in CHA and NCHA. The substitution of cations and anions in the HA structure was confirmed by the decrease of the d[002] spacing of HA with substitution of ions with an ionic radius less than that of Ca or P. The DTPA-extractable Cu ranged from 8 to 8429 mg kg-1, Zn ranged from 57 to 1279 mg kg-1, Fe from 211 to 2573 mg kg-1, and Mn from 190 to 1719 mg kg-1, depending on the substitution level of each element in HA. Nutrient-substituted HA has the potential to be used as a slow-release fertilizer to supply micronutrients, S, and Mg in addition to Ca and P.

Golden, D. C.; Ming, D. W.

1999-01-01

177

Nutrient and nonnutrient renal blood flow  

SciTech Connect

The role of prostaglandins in the distribution of total renal blood flow (TRBF) between nutrient and nonnutrient compartments was investigated in anesthetized mongrel dogs. Renal blood flow distribution was assessed by the xenon 133 freeze-dissection technique and by rubidium 86 extraction after ibuprofen treatment. Ibuprofen (13 mg/kg) significantly decreased TRBF by 16.3% +/- 1.2% (mean +/- SEM electromagnetic flow probe; p less than 0.005), but did not alter blood flows to the outer cortex (3.7 vs 4.3 ml/min per gram), the inner cortex (2.6 vs 2.7 ml/min per gram), and the other medulla (1.5 vs 1.5 ml/min per gram), which suggests a decrease in nonnutrient flow. In a separate group of animals the effect of reduced blood flow on the nutrient and nonnutrient components was determined by mechanically reducing renal arterial blood flow by 48%. Unlike the ibuprofen group, nutrient blood flows were proportionally reduced with the mechanical decrease in TRBF in the outer cortex (1.9 ml/min per gram, p less than 0.05), the inner cortex (1.4 ml/min per gram, p less than 0.05), and the outer medulla (0.8 ml/min per gram, p less than 0.01). These results indicate no shift between nutrient and nonnutrient compartments. Nutrient and nonnutrient renal blood flows of the left kidney were also determined by 86Rb extraction. After ibuprofen treatment, nonextracted 86Rb decreased to 12.1% from the control value of 15.6% (p less than 0.05). Mechanical reduction of TRBF did not significantly decrease the proportion of unextracted 86Rb (18.7%).

Young, J.S.; Passmore, J.C.; Hartupee, D.A.; Baker, C.H. (Univ. of Louisville, KY (USA))

1990-06-01

178

CH4 emissions from two floodplain fens of differing nutrient status  

NASA Astrophysics Data System (ADS)

Floodplain fens emit large amounts of CH4 in comparison with ombrotrophic bogs. Little is known about the effect of fluvial nitrogen (N) and phosphorus (P) on CH4 dynamics in fens, although N and P affect carbon (C) dynamics indirectly in other environments by controlling plant growth and root exudate release, as well as by altering microbial biomass and decomposition rates. This study aimed to compare CH4 emissions from two floodplain fen sites which differ in nutrient status, Sutton Fen (52°45'N 001°30'E) and Strumpshaw Fen (52°36'N 001°27'E), in the Norfolk Broadland of England. Sutton and Strumpshaw Fen are under conservation management and both sites have water levels that vary within a few decimetres above and below the surface. The sites are dominated by reed (Phragmites australis). Areas within the fens where the reed was cut in 2009 were chosen for this study. Average plant height and mean aboveground biomass were significantly greater at Strumpshaw (107.2 ± 7.8 cm and 1578 ± 169 g m-2, respectively) than Sutton (56.5 ± 5.1 cm and 435 ± 42 g m-2) as were mean foliar N and P contents (21.8 ± 1.5 g kg-1 and 2.0 ± 0.2 g kg-1 at Strumpshaw, versus 16.3 ± 1.5 g kg-1 and 1.1 ± 0.1 g kg-1 at Sutton). Foliar NPK ratios showed Strumpshaw to be N limited, whereas Sutton was both N and P limited, depending on microsite. Surface peat N and P contents were also greater at Strumpshaw (28.3 ± 0.35 g kg-1 and 0.78 ± 0.02 g kg-1, respectively) than Sutton (18.32 ± 0.87 g kg-1 and 0.43 ± 0.1 g kg-1). These results indicate clear differences in nutrient status between the two sites despite their geographical proximity and other similarities. CH4 emissions were monitored monthly between 19th June 2012 and 2nd September 2013 using tall static chambers and glass funnel-traps, the latter for ebullition. Steady fluxes did not follow a clear seasonal pattern; however, emission was greatest in the summer months. Strumpshaw had a greater range in efflux (0.25 to 134.2 mg CH4 m-2 h-1) than Sutton (0.17 to 29.82 mg CH4 m-2 h-1). Ebullition was generally greater at Sutton throughout the study period, with rates ranging from 0 to 62.09 mg CH4 m-2 h-1 and 0 to 19.30 mg CH4 m-2 h-1 for Sutton and Strumpshaw, respectively. Fluxes were generally within the range of values reported in the literature for ebullition (0 to 466 mg CH4 m-2 h-1) and steady fluxes (0 to 76.83 mg CH4 m-2 h-1). Results show the importance of floodplain fens for CH4 emission, and more research needs to be undertaken to fully understand the factors controlling CH4 fluxes from these systems.

Stanley, Kieran; Heppell, Catherine; Belyea, Lisa; Baird, Andrew

2014-05-01

179

Eutrophication of Buttermilk Bay, a cape cod coastal embayment: Concentrations of nutrients and watershed nutrient budgets  

NASA Astrophysics Data System (ADS)

Nutrient concentrations in Buttermilk Bay, a coastal embayment on the northern end of Buzzards Bay, MA, are higher in the nearshore where salinities are lower. This pattern suggests that freshwater sources may contribute significantly to nutrient inputs into Buttermilk Bay. To evaluate the relative importance of the various sources we estimated inputs of nutrients by each major source into the watershed and into the bay itself. Septic systems contributed about 40% of the nitrogen and phosphorus entering the watershed, with precipitation and fertilizer use adding the remainder. Groundwater transported over 85% of the nitrogen and 75% of the phosphorus entering the bay. Most nutrients entering the watershed failed to reach the bay; uptake by forests, soils, denitrification, and adsorption intercepted two-thirds of the nitrogen and nine-tenths of the phosphorus that entered the watershed. The nutrients that did reach the bay most likely originated from subsoil injections into groundwater by septic tanks, plus some leaching of fertilizers. Buttermilk Bay water has relatively low nutrient concentrations, probably because of uptake of nutrients by macrophytes and because of relatively rapid tidal flushing. Annual budgets of nutrients entering the watershed showed a low nitrogen-to-phosphorus ratio of 6, but passage of nutrients through the watershed raised N/P to 23, probably because of adsorption of PO4 during transit. The N/P ratio of water that leaves the watershed and presumably enters the bay is probably high enough to maintain active growth of nitrogenlimited coastal producers. There is a seasonal shift in N/P in the water column of Buttermilk Bay. N/P exceeded the 16?1 Redfield ratio during midwinter; the remainder of the year N/P fell below 16?1. This suggests that annual budgets do not provide sufficiently detailed data with which to interpret nutrient-limitation of producers. Further, some idea of water turnover is also needed to evaluate impact of loading rates. Urbanization of watersheds seems to increase loadings to nearshore environments, and to shift the nutrient loadings delivered to coastal waters to relatively high N-to-P ratios, potentially stimulating growth of nitrogen-limited primary producers.

Valiela, Ivan; Costa, Joseph E.

1988-07-01

180

Seasonal Asynchrony in Terrestrial Nutrient Production and Demand Drives Nutrient Delivery to Arctic Streams  

NASA Astrophysics Data System (ADS)

Plant species that currently dominate the terrestrial plant community in the Arctic become dormant and cease to require nutrients shortly after the peak in the growing season in late-July to early August. However, deeper soils in the active layer may not freeze until much later, in mid-October to mid-November. Thus, there is a period of time in which vegetation demand for nutrients is low but soils are sufficiently warm to maintain microbial activity and to allow continued runoff from land to streams. Previously we hypothesized that this "seasonal asynchrony" in nutrient dynamics should lead to increased nutrient loading to streams in the fall. We used a small watershed close to the Toolik Lake Field Station on the North Slope of Alaska to test this hypothesis. We collected phenological observations to assess plant senescence, spectral irradiance data to calculate vegetation "greenness" (NDVI), and samples of stream water for nutrient analyses from mid-July through early October 2011. We found, as hypothesized, that the concentration and flux of nitrate increased significantly in this test watershed coincident with declines in NDVI that occur as plants senesced (Figure). Increases in other important nutrients (phosphate and ammonium) were not significant. We confirmed that this was a general phenomenon and not a unique characteristic of the test watershed by sampling nutrients in five other watersheds in the area ranging from tundra to mountain terrain. All watersheds exhibited the same general behavior of elevated nitrate during the transition from the growing season to the early winter season. We conclude that this is a general phenomenon that we have not observed previously because our long-term water research and monitoring programs have, until recently, been restricted to the core summer season. Increased nutrient loading due to seasonal asynchrony in nutrient dynamics is unlikely to be a new phenomenon. However, we expect the duration of this seasonal asynchrony - the period between plant dormancy and complete freeze up of soils - to increase as the Arctic region continues to warm. The effects of greater nutrient loading to arctic streams late in the season are unknown but include alteration of local stream ecosystem dynamics and/or increased delivery of nutrients to oligotrophic coastal and marine ecosystems.

Bowden, W. B.; Khosh, M. S.; Waldvogel, G.; Gooseff, M. N.; Wollheim, W. M.; Whittinghill, K. A.; Wlostowski, A. N.; Jacobson, A. D.; McClelland, J. W.; Douglas, T. A.; Lehn, G. O.; Barker, A.

2012-12-01

181

Global nutrients data synthesis based on Reference Material of Nutrients of Seawater  

NASA Astrophysics Data System (ADS)

Realistic distributions of nitrate, phosphate and silicate and inventories of them in the world's ocean are basic issues of geochemical study of nitrogen, phosphorous and silicon cycles as well as tracer use of nutrients for deep ocean circulation. WOA09 and WGHC were global hydrographic datasets created by objective analysis and offset correction/objective analysis, respectively. However synthesis using mathematics methods and experience could get apparent global comparability but does not have a firm foundation, therefore accuracy is unknown for nutrients data in WOA05/09 and WGHC. Recently hydrographic dataset such as CARINA and PACIFICA were also created by synthesis. We did global synthesis work based on Reference Material of Nutrients in Seawater (RMNS) for WOCE/CLIVAR cruises datasets, WGHC datasets and some new hydrographic cruises which cover the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Southern Ocean and the Arctic Ocean. Among 69982 profiles in 5174 cruises, we could put correction factors of nutrients concentration for 14491 profiles in 268 cruises for nitrate, 18378 profiles in 412 cruises for phosphate and 15825 profiles in 268 cruises for silicate. Global Nutrients Dataset 2010, GND10, is newly created as 0.5 deg. × 0.5 deg. and 50 m interval of 138 levels gridded dataset based on corrected nutrients profiles described above. One feature of GND10 is that nitrate vs. phosphate ratio in deep waters in WOA dataset showed a peak at 14.6 while nitrate vs. phosphate ratio in GND10 showed a peak at 14.3 and kurtosis of frequency distribution of nitrate vs. phosphate ratio is larger in GND10 dataset rather than that in WOA dataset. A reason of larger kurtosis of distribution of nitrate vs. phosphate ratio might be that comparability of nitrate and phosphate concentration data was improved. Newly created GND10 can provide more realistic distribution of nutrients in the world ocean because comparability of nutrients concentration in GND10 is improved based on RMNS. The GND10 would be useful to study changes in the distribution of concentrations of nutrients in the world ocean and also useful as new initial conditions for modelers who studies global changes. Carbonate system data and oxygen data will be merged with factor corrected nutrients data to study coupling of carbonate system and nutrients cycles, too.

Aoyama, Michio; Murata, Akihiko; Nishino, Shigeto

2013-04-01

182

Improving models of forest nutrient export with equations that predict the nutrient concentration of tree compartments  

Microsoft Academic Search

– \\u000a \\u000a • The objective of this study was to explore the distribution of major nutrients (N, P, K, Ca and Mg) in the aboveground compartments\\u000a of an intensively managed tree species (Pinus pinaster Ait.). A total of 53 trees were cut down in even-aged stands respectively 8, 16, 26, 32 and 40 years old. The nutrient concentrations\\u000a of the aboveground

Laurent Augusto; Céline Meredieu; Didier Bert; Pierre Trichet; Annabel Porté; Alexandre Bosc; Frédéric Lagane; Denis Loustau; Sylvain Pellerin; Frédéric Danjon; Jacques Ranger; Jacques Gelpe

2008-01-01

183

Changes in nutrient structure of river-dominated coastal waters: stoichiometric nutrient balance and its consequences  

Microsoft Academic Search

We present an analysis of extensive nutrient data sets from two river-dominated coastal ecosystems, the northern Adriatic Sea and the northern Gulf of Mexico, demonstrating significant changes in surface nutrient ratios over a period of 30 years. The silicon:nitrogen ratios have decreased, indicating increased potential for silicon limitation. The nitrogen:phosphorus and the silicon:phosphorus ratios have also changed substantially, and the

Dubravko Justic; Nancy N. Rabalais; R. Eugene Turner; Quay Dortch

1995-01-01

184

NUTRIENT DYNAMICS IN RELATION TO GEOMORPHOLOGY OF RIVERINE WETLANDS  

EPA Science Inventory

Variation in water depth and soil properties associated with geomorphic structures can affect riverine wetland nutrient dynamics by altering biogeochemical processes. We examined the seasonal influence of soils and geomorphology on nutrient forms and concentrations in riverine we...

185

Water and Nutrient Budgets for Cayuga Lake, New York.  

National Technical Information Service (NTIS)

A study initiated in June 1970 to measure the nutrient inputs for Lake Cayuga via streams and precipitation is reported. Hydrologic components including runoff, outlet discharge and lake renewal time, and hydrologic budget are discussed and nutrient budge...

G. E. Likens

1974-01-01

186

Comparison of Nutrient Drivers and Response Metrics in Oregon Estuaries  

EPA Science Inventory

With the goal of assessing sensitivity to nutrient enrichment, we present a cross-estuary comparison of nutrient sources, levels, and biological responses (phytoplankton and macroalgae) for thirteen Oregon estuaries. Nitrogen levels in the upstream portions of the estuaries are ...

187

Impact of Intensive Harvesting on Forest Nutrient Cycling.  

National Technical Information Service (NTIS)

The Symposium, 'Impact of Intensive Harvesting on Forest Nutrient Cycling', held August 13-16, 1979 at Syracuse, New York, is the result of mutual interests. The concern with accelerated nutrient and organic removals is of great practical significance for...

1979-01-01

188

Nutrient Accumulation in Planted Red and Jack Pine.  

National Technical Information Service (NTIS)

The purpose of this paper are to compare the nutrient accumulation in adjacent plantations of red and jack pine, and to develop models to predict nutrient content in these species as functions of easily measured stand variables.

D. H. Alban

1988-01-01

189

Nutrient Transformations in Mass Cultures of Marine Algae.  

National Technical Information Service (NTIS)

The report presents a novel concept for controlling the discharge of wastewater-borne nutrients (primarily nitrogen) into coastal marine waters. The process, called 'controlled eutrophication,' involves, the regulated assimilation of nutrients by algae in...

J. C. Goldman J. H. Ryther

1974-01-01

190

RESPONSE OF LAYERS TO LOW NUTRIENT DENSITY DIETS  

Microsoft Academic Search

Two experiments were conducted to test the ability of layers to increase their feed intake when fed diets of reduced nutrient density. Shaver White layers at 19 wk of age were fed diets at 2900 kcal ME\\/kg and 18.2% crude protein, or ?5, ?10, or ?15% reduced nutrient density. In Experiment 1 reduced nutrient density was achieved by adding a

S. LEESON; J. D. SUMMERS; L. J. CASTON

191

A Nutrient Density-Nutrition Education Program for Elementary Schools.  

ERIC Educational Resources Information Center

Presents a nutrient density-nutrition education program that was developed and evaluated for students K-6. The program is designed to be integrated into existing curricula. Nutrient density, which compares the nutrients in food with its caloric content, serves as the conceptual framework of the program. (Author/MA)

Brown, Guendoline; And Others

1979-01-01

192

Nutrient and Temperature Limitation of Bacterioplankton Growth in Temperate Lakes  

Microsoft Academic Search

Limitation of bacterioplankton production by nutrients and temperature was investigated in eight temperate lakes in summer. Six of the lakes were resampled in autumn. The lakes differ in nutrient content, water color, and concentration of dissolved organic carbon. Nutrients (phosphorus, nitrogen, and organic carbon) were added alone and in all possible combinations to filtered lake water inoculated with bacteria from

K. Vrede

2005-01-01

193

Nutrient Input into the Caspian Sea with River Runoff  

Microsoft Academic Search

Long-term observational data are used to compare and analyze time and space variations in the concentrations of nutrients in the water of major rivers flowing into the Caspian Sea and assess the nutrients runoff into the sea. Annual variations in the normal monthly values of river runoff and nutrient compound concentrations and input into the sea are considered (18 compounds

A. V. Leonov; N. A. Nazarov

2001-01-01

194

Nutrient uptake and benthic regeneration in Danube Delta Lakes  

Microsoft Academic Search

We investigated the nutrient uptake capacity of three lakes (Uzlina, Matita and Rosu) within the Danube Delta during high water level in June and low water level in September 1999. Special emphasis was placed on nutrient cycling at the sediment-water interface and on the self-purification capacity of the lakes in the Danube Delta. In order to estimate the nutrient uptake

Jana Friedrich; Christian Dinkel; Erwin Grieder; Silviu Radan; Dan Secrieru; Sandra Steingruber; Bernhard Wehrli

2003-01-01

195

Nitrogenous Nutrition of Marine Phytoplankton in Nutrient-Depleted Waters  

Microsoft Academic Search

Variability in the small-scale temporal and spatial patterns in nitrogenous nutrient supply, coupled with an enhanced uptake capability for nitrogenous nutrients induced by nitrogen limitation, make it possible for phytoplankton to maintain nearly maximum rates of growth at media nutrient concentrations that cannot be quantified with existing analytical techniques.

James J. McCarthy; Joel C. Goldman

1979-01-01

196

Redfield ratios of remineralization determined by nutrient data analysis  

Microsoft Academic Search

A nonlinear inverse method is applied to nutrient data upon approximately 20 neutral surfaces in each of the South Atlantic, Indian, and Pacific basins, between 400 and 4000 m depth. By accounting for the gradients in nutrients due to the mixing of [open quotes]preformed[close quotes] concentrations of the major water masses, the nutrient changes due to biological activity are examined,

Laurence A. Anderson; Jorge L. Sarmiento

1994-01-01

197

Posidonia oceanica meadow: a low nutrient high chlorophyll (LNHC) system?  

PubMed Central

Background In spite of very low nutrient concentrations in its vicinity – both column and pore waters-, the Posidonia oceanica of the Revellata Bay displays high biomass and productivity. We measured the nutrient fluxes from the sediment into the water enclosed among the leaf shoots ("canopy water") to determine if it is possible source of nutrients for P. oceanica leaves. Results During the summer, the canopy water appears to act as a nutrient reservoir for the plant. During that period, the canopy water layer displays both a temperature 0.5°C cooler than the upper water column, and a much higher nutrient content, as shown in this work using a very simple original technique permitting to sample water with a minimal disturbance of the water column's vertical structure. Despite low nutrient concentrations in pore water, mean net fluxes were measured from the sediment to the canopy water. These fluxes are sufficient to provide 20% of the mean daily nitrogen and phosphorus requirement of the P. oceanica shoots. Conclusion An internal cycling of nutrients from P. oceanica senescent leaves was previously noted as an efficient strategy to help face low nutrient availability. The present study points out a second strategy which consists in holding back, in the canopy, the nutrients released at the water-sediment interface. This process occurs when long leaves, during poor nutrient periods in the water column, providing, to P. oceanica, the possibility to develop, high biomass, high chlorophyll quantities in low nutrient environment (a Low Nutrients High Chlorophyll system).

Gobert, Sylvie; Laumont, Noemie; Bouquegneau, Jean-Marie

2002-01-01

198

Testate Amoebae and Nutrient Cycling with Particular Reference to Soils  

Microsoft Academic Search

We asked the following question: Is the lack of attention given to testate amoebae, and other protists, in studies of nutrient cycling justified by their relative unimportance or are we ignoring key players in nutrient cycling and other ecological processes? We review various aspects of the ecology of testates relevant to their role in nutrient cycling. These include their food

David M. Wilkinson; Edward A. D. Mitchell

2010-01-01

199

Study review : The European Nutrient Database (ENDB) for Nutritional Epidemiology  

Microsoft Academic Search

Food composition databases (FCDB), as well as standardized calculation procedures are required for international studies on nutrition and disease to calculate nutrient intakes across countries. Comparisons of national FCDBs have shown that major improvements are needed in standardization and documentation at the food and nutrient levels to minimize systematic and random errors in nutrient intake estimations. The International Agency for

U. R. Charrondiere; J. Vignat; A. Moller; J. Ireland; W. Becker; S. Church; A. Farran; J. Holden; C. Klemm; A. Linardou; D. Mueller; Staveren van W. A

2002-01-01

200

The European Nutrient Database (ENDB) for Nutritional Epidemiology  

Microsoft Academic Search

Food composition databases (FCDB), as well as standardized calculation procedures are required for international studies on nutrition and disease to calculate nutrient intakes across countries. Comparisons of national FCDBs have shown that major improvements are needed in standardization and documentation at the food and nutrient levels to minimize systematic and random errors in nutrient intake estimations. The International Agency for

U. R. Charrondiere; J. Vignat; A. Møller; J. Ireland; W. Becker; S. Church; A. Farran; J. Holden; C. Klemm; A. Linardou; D. Mueller; S. Salvini; L. Serra-Majem; G. Skeie; W. van Staveren; I. Unwin; S. Westenbrink; N. Slimani; E. Ribol

2002-01-01

201

SPATIAL VARIATIONS IN NUTRIENT AND MICROBIAL TRANSPORT FROM FEEDLOT SURFACES  

Microsoft Academic Search

Nutrient and microbial transport by runoff may vary at different locations within a beef cattle feedlot. If the areas making the largest contributions to nutrient and microbial transport can be identified, it may be possible to institute site-specific management practices to reduce runoff nutrient and microbial transport. The objectives of this study were to: (1) measure selected feedlot soil properties

J. E. Gilley; E. D. Berry; R. A. Eigenberg; D. B. Mar; B. L. Woodbury

202

Cadmium toxicity to two marine phytoplankton under different nutrient conditions  

Microsoft Academic Search

Cd accumulation and toxicity in two marine phytoplankton (diatom Thalassiosira weissflogii and dinoflagellate Prorocentrum minimum) under different nutrient conditions (nutrient-enriched, N- and P-starved conditions) were examined in this study. Strong interactions between the nutrients and Cd uptake by the two algal species were found. Cd accumulation as well as N and P starvation themselves inhibited the assimilation of N, P,

Ai-Jun Miao; Wen-Xiong Wang

2006-01-01

203

CO 2 ENRICHMENT AND NUTRIENT AVAILABILITY ALTER ECTOMYCORRHIZAL FUNGAL COMMUNITIES  

Microsoft Academic Search

Ectomycorrhizal fungi (EMF), a phylogenetically and physiologically diverse guild, form symbiotic associations with many trees and greatly enhance their uptake of nutrients and water. Elevated CO2, which increases plant carbon supply and demand for mineral nutrients, may change the composition of the EMF community, possibly altering nutrient uptake and ultimately forest productivity. To assess CO2 effects on EMF communities, we

Jeri Lynn Parrent; William F. Morris; Rytas Vilgalys

2006-01-01

204

Nutrient detection by incretin hormone secreting cells  

PubMed Central

The hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulintropic polypeptide (GIP) are secreted after a meal. Like other enteroendocrine hormones they help to orchestrate the bodies' response to the availability of newly absorbable nutrients and are noteworthy as they stimulate postprandial insulin secretion, underlying what is known as the incretin effect. GLP-1-mimetics are now widely used in the treatment of type 2 diabetes and advantages over older insulinotropic therapies include weight loss. An alternative treatment regime might be the recruitment of endogenous GLP-1, however, very little is known about the physiological control of enteroendocrine responses. This review focuses on the molecular mechanisms to detect nutrient arrival in the gut that have been implicated within the incretin secreting cells.

Diakogiannaki, Eleftheria; Gribble, Fiona M.; Reimann, Frank

2012-01-01

205

Nutrient Cycles and Pollution, Lake Michigan Style  

NSDL National Science Digital Library

This “clicker case” introduces students to the basics of nutrient cycling using a recent example of the expansion of a refinery on Lake Michigan. The story is told through a series of news clips from Chicago’s National Public Radio affiliate, WBEZ, which covers the northeastern Illinois and northwestern Indiana region.  The case is presented in class using a series of PowerPoint slides (~3.7MB) punctuated by questions that the students answer using electronic personal response systems, or "clickers." The case was designed for use in an upper-level introductory ecology course. It would be equally well suited in lower-level ecology courses as well as environmental science courses, and in an introductory biology course that covers nutrient cycles and/or pollution.

Heinz, Cheryl A.

2010-01-01

206

Spatial variability of soil nutrients and site-specific nutrient management in the P.R. China  

Microsoft Academic Search

Preliminary studies on the spatial variability in available nutrient content in agricultural fields under both large scale and small scale operation in China were conducted, and the different technical approaches to realize site specific nutrient management developed. Results indicated that significant spatial variability of all essential plant nutrient exist in different operating systems and at various scales. Under small scale

Jiyun Jin; Cheng Jiang

2002-01-01

207

Food and nutrient intake of Hallelujah vegetarians  

Microsoft Academic Search

Reports the results of a survey of followers of the mostly raw, pure vegetarian, Hallelujah diet, which is promoted by the Hallelujah Acres Foundation in the USA. Seven-day semi-quantitative dietary records kept by 141 followers of the diet were collected and analyzed for nutrient intake. Claims self-reported improvements in health and quality of life after adoption of the diet were

Michael S. Donaldson

2001-01-01

208

Chasing Nutrients with an Arctic Sedge  

NASA Astrophysics Data System (ADS)

Climate change has put the Arctic into a state of flux. Understanding the effects an altered climate will have on vegetation and nutrient cycling requires more knowledge of the key plant and soil functions of major arctic ecosystems. One of these ecosystems, moist acidic tussock tundra, is dominated by a single plant species, the tussock-forming sedge Eriophorum vaginatum. This plant has unusual underground biomass: long, fast-growing, non-branching, non-mycorrhizal roots. In contrast to many other plants in nutrient-limiting environments, this sedge is highly successful without maximizing its root surface area to volume ratio. The benefits of this growth strategy to the plants and its effects on the accompanying soil-microbe-plant relationships are not fully understood. One possibility is that the roots may help the plant take advantage of nutrients released into the active layer of soil as it thaws in the spring. The roots may also stimulate microbial activity, increasing nutrient turnover and availability. A study was undertaken to explore the nitrogen (N) and carbon (C) dynamics in these plants, as well as the microbial populations associated with active E. vaginatum roots. Intact tussock microcosms (plant and accompanying soil) were removed from the tundra and cultivated in transparent boxes. Half the plants were kept in light to encourage photosynthesis (and thus greater plant activity), while the other half was kept in the dark to inhibit it. Using a 15N isotopic tracer injected at the extremity of root penetration into the soil, the N uptake capacity of E. vaginatum roots at depth was explored. This uptake capacity is compared to measures of plant activity, microbial activity, and soil solution chemistry in order to paint a clearer picture of the role of E. vaginatum in the soil ecosystem.

Iverson, S. L.; Schimel, J.

2013-12-01

209

Biotechnology: a solution for improving nutrient bioavailability.  

PubMed

Biotechnology strategies are now available to improve the amount and availability of nutrients in plant crops. Those strategies include simple plant selection for varieties with high nutrient density in the seeds, cross-breeding for incorporating a desired trait within a plant, and genetic engineering to manipulate the nutrient content of the plant. In plant cross-breeding, all genes of the parent plants are combined and the progeny have both desirable and undesirable traits. To eliminate undesirable traits, plant breeders "back-cross" the new plant varieties with other plants over several generations. This technique, called hybridization, has been used to create varieties of low-phytate corn, barley, and rice. Using the techniques of genetic engineering, the gene(s) encoding for a desired trait(s) in a plant are introduced in a precise and controlled manner within a relatively short period of time. Golden rice, containing carotenoids, and rice with higher amounts of iron, are two examples of genetically engineered plants for improved nutrition. Genetic engineering has tremendous potential for revolutionizing nutrition. However, public concerns regarding safety, appearance, and ethics must be overcome before these products can be effectively introduced into the food supply. PMID:11887755

King, Janet C

2002-01-01

210

Nutrient Addition Dramatically Accelerates Microbial Community Succession  

PubMed Central

The ecological mechanisms driving community succession are widely debated, particularly for microorganisms. While successional soil microbial communities are known to undergo predictable changes in structure concomitant with shifts in a variety of edaphic properties, the causal mechanisms underlying these patterns are poorly understood. Thus, to specifically isolate how nutrients – important drivers of plant succession – affect soil microbial succession, we established a full factorial nitrogen (N) and phosphorus (P) fertilization plot experiment in recently deglaciated (?3 years since exposure), unvegetated soils of the Puca Glacier forefield in Southeastern Peru. We evaluated soil properties and examined bacterial community composition in plots before and one year after fertilization. Fertilized soils were then compared to samples from three reference successional transects representing advancing stages of soil development ranging from 5 years to 85 years since exposure. We found that a single application of +NP fertilizer caused the soil bacterial community structure of the three-year old soils to most resemble the 85-year old soils after one year. Despite differences in a variety of soil edaphic properties between fertilizer plots and late successional soils, bacterial community composition of +NP plots converged with late successional communities. Thus, our work suggests a mechanism for microbial succession whereby changes in resource availability drive shifts in community composition, supporting a role for nutrient colimitation in primary succession. These results suggest that nutrients alone, independent of other edaphic factors that change with succession, act as an important control over soil microbial community development, greatly accelerating the rate of succession.

Knelman, Joseph E.; Schmidt, Steven K.; Lynch, Ryan C.; Darcy, John L.; Castle, Sarah C.; Cleveland, Cory C.; Nemergut, Diana R.

2014-01-01

211

Bile acids are nutrient signaling hormones.  

PubMed

Bile salts play crucial roles in allowing the gastrointestinal system to digest, transport and metabolize nutrients. They function as nutrient signaling hormones by activating specific nuclear receptors (FXR, PXR, Vitamin D) and G-protein coupled receptors [TGR5, sphingosine-1 phosphate receptor 2 (S1PR2), muscarinic receptors]. Bile acids and insulin appear to collaborate in regulating the metabolism of nutrients in the liver. They both activate the AKT and ERK1/2 signaling pathways. Bile acid induction of the FXR-? target gene, small heterodimer partner (SHP), is highly dependent on the activation PKC?, a branch of the insulin signaling pathway. SHP is an important regulator of glucose and lipid metabolism in the liver. One might hypothesize that chronic low grade inflammation which is associated with insulin resistance, may inhibit bile acid signaling and disrupt lipid metabolism. The disruption of these signaling pathways may increase the risk of fatty liver and non-alcoholic fatty liver disease (NAFLD). Finally, conjugated bile acids appear to promote cholangiocarcinoma growth via the activation of S1PR2. PMID:24819989

Zhou, Huiping; Hylemon, Phillip B

2014-08-01

212

Long?Term Integrated Nutrient Management for Rice?Based Cropping Pattern: Effect on Growth, Yield, Nutrient Uptake, Nutrient Balance Sheet, and Soil Fertility  

Microsoft Academic Search

A 7?year?long field trial was conducted on integrated nutrient management for a dry season rice (Boro)–green manure (GM)–wet season rice (T. Aman) cropping system at the Bangladesh Rice Research Institute Farm, Gazipur during 1993–1999. Five packages of inorganic fertilizers, cow dung (CD), and GM dhaincha (Sesbania aculeata) were evaluated for immediate and residual effect on crop productivity, nutrient uptake, soil?nutrient

P. K. Saha; M. Ishaque; M. A. Saleque; M. A. M. Miah; G. M. Panaullah; N. I. Bhuiyan

2007-01-01

213

Simultaneous high-biomass protein production and nutrient removal using Spirulina maxima in sea water supplemented with anaerobic effluents  

Microsoft Academic Search

Maximum protein accumulation (71%, w\\/w) and nutrient removal by a mutant strain of Spirulina maxima growing on sea water supplemented with anaerobically treated pig slurry was achieved at 30°C with constant illumination (60 to 70 µEm-2s-1), using a flow rate of 14.5 cm s-1 (20 rev. min-1 of a paddle wheel). Total phosphates were decreased by 99% and all ammonia-N

E. J. Olguín; B. Hernández; A. Araus; R. Camacho; R. González; M. E. Ramírez; S. Galicia; G. Mercado

1994-01-01

214

Nutrient sensing and signaling in the yeast Saccharomyces cerevisiae.  

PubMed

The yeast Saccharomyces cerevisiae has been a favorite organism for pioneering studies on nutrient-sensing and signaling mechanisms. Many specific nutrient responses have been elucidated in great detail. This has led to important new concepts and insight into nutrient-controlled cellular regulation. Major highlights include the central role of the Snf1 protein kinase in the glucose repression pathway, galactose induction, the discovery of a G-protein-coupled receptor system, and role of Ras in glucose-induced cAMP signaling, the role of the protein synthesis initiation machinery in general control of nitrogen metabolism, the cyclin-controlled protein kinase Pho85 in phosphate regulation, nitrogen catabolite repression and the nitrogen-sensing target of rapamycin pathway, and the discovery of transporter-like proteins acting as nutrient sensors. In addition, a number of cellular targets, like carbohydrate stores, stress tolerance, and ribosomal gene expression, are controlled by the presence of multiple nutrients. The protein kinase A signaling pathway plays a major role in this general nutrient response. It has led to the discovery of nutrient transceptors (transporter receptors) as nutrient sensors. Major shortcomings in our knowledge are the relationship between rapid and steady-state nutrient signaling, the role of metabolic intermediates in intracellular nutrient sensing, and the identity of the nutrient sensors controlling cellular growth. PMID:24483210

Conrad, Michaela; Schothorst, Joep; Kankipati, Harish Nag; Van Zeebroeck, Griet; Rubio-Texeira, Marta; Thevelein, Johan M

2014-03-01

215

Stable isotope-labelled feed nutrients to assess nutrient-specific feed passage kinetics in ruminants.  

PubMed

Knowledge of digesta passage kinetics in ruminants is essential to predict nutrient supply to the animal in relation to optimal animal performance, environmental pollution and animal health. Fractional passage rates (FPR) of feed are widely used in modern feed evaluation systems and mechanistic rumen models, but data on nutrient-specific FPR are scarce. Such models generally rely on conventional external marker techniques, which do not always describe digesta passage kinetics in a satisfactory manner. Here the use of stable isotope-labelled dietary nutrients as a promising novel tool to assess nutrient-specific passage kinetics is discussed. Some major limitations of this technique include a potential marker migration, a poor isotope distribution in the labelled feed and a differential disappearance rate of isotopes upon microbial fermentation in non-steady state conditions. Such limitations can often be circumvented by using intrinsically stable isotope-labelled plant material. Data are limited but indicate that external particulate markers overestimate rumen FPR of plant fibre compared with the internal stable isotope markers. Stable isotopes undergo the same digestive mechanism as the labelled feed components and are thus of particular interest to specifically measure passage kinetics of digestible dietary nutrients. © 2013 Society of Chemical Industry. PMID:24114801

Warner, Daniel; Dijkstra, Jan; Hendriks, Wouter H; Pellikaan, Wilbert F

2014-03-30

216

Enhancing crop growth, nutrients availability, economics and beneficial rhizosphere microflora through organic and biofertilizers  

Microsoft Academic Search

Field experiment was conducted on fodder maize to explore the potential of integrated use of chemical, organic and biofertilizers\\u000a for improving maize growth, beneficial microflora in the rhizosphere and the economic returns. The treatments were designed\\u000a to make comparison of NPK fertilizer with different combinations of half dose of NP with organic and biofertilizers viz. biological\\u000a potassium fertilizer (BPF), Biopower,

Ghulam Jilani; Abida Akram; Raja M. Ali; Fauzia Y. Hafeez; Imran H. Shamsi; Arshad N. Chaudhry; Abid G. Chaudhry

2007-01-01

217

Nutrient fluxes at the landscape level and the R* rule  

USGS Publications Warehouse

Nutrient cycling in terrestrial ecosystems involves not only the vertical recycling of nutrients at specific locations in space, but also biologically driven horizontal fluxes between different areas of the landscape. This latter process can result in net accumulation of nutrients in some places and net losses in others. We examined the effects of such nutrient-concentrating fluxes on the R* rule, which predicts that the species that can survive in steady state at the lowest level of limiting resource, R*, can exclude all competing species. To study the R* rule in this context, we used a literature model of plant growth and nutrient cycling in which both nutrients and light may limit growth, with plants allocating carbon and nutrients between foliage and roots according to different strategies. We incorporated the assumption that biological processes may concentrate nutrients in some parts of the landscape. We assumed further that these processes draw nutrients from outside the zone of local recycling at a rate proportional to the local biomass density. Analysis showed that at sites where there is a sufficient biomass-dependent accumulation of nutrients, the plant species with the highest biomass production rates (roughly corresponding to the best competitors) do not reduce locally available nutrients to a minimum concentration level (that is, minimum R*), as expected from the R* rule, but instead maximize local nutrient concentration. These new results require broadening of our understanding of the relationships between nutrients and vegetation competition on the landscape level. The R* rule is replaced by a more complex criterion that varies across a landscape and reduces to the R* rule only under certain limiting conditions.

Ju, Shu; DeAngelis, Donald L.

2010-01-01

218

Predicting nutrient responses in poultry: future challenges.  

PubMed

Predicting the response of poultry to nutrients has progressed to a stage where it is now not only possible to predict voluntary feed intake accurately, but broiler feeds and feeding programmes may now be optimised using the more advanced simulation models. Development of such prediction models has stimulated useful and purposeful research targeted at filling the gaps in our knowledge of critical aspects of the theory incorporated into these models. The aim of this paper was to review some of these past developments, discuss the controversy that exists in designing and interpreting response experiments, and highlight some of the most recent challenges related to the prediction of responses to nutrients by poultry. These latter include differences, brought about by selection for diverse goals, that have become apparent between modern broiler strains in their responses in feed intake and mortality, which are not independent of level of feeding or strain of broiler, as was previously believed. Uniformity, an important quality criterion in broiler processing, is also not independent of level of feeding, and the effect may now be predicted using stochastic models. It is not yet clear whether breast meat yield, the carcass component of broilers yielding the highest returns, is a function of the strain of broiler or simply that of the protein weight of the bird when processed. An important aspect of response prediction is dealing with constraints to performance: whereas it is relatively straightforward to simulate the potential performance of a broiler, such performance is often constrained by the physical, social and infectious environment, among others, providing a challenge to modellers attempting to predict actual performance. Some of these constraints to potential performance have not yet been adequately described, but are now receiving attention, suggesting that nutrient responses in poultry have the potential to be more accurately predicted in the future. PMID:22444210

Gous, R M

2007-02-01

219

Nutrient limitation in Northern Gulf of Mexico (NGOM): phytoplankton communities and photosynthesis respond to nutrient pulse.  

PubMed

Although the Mississippi-Atchafalaya River system exports large amounts of nutrients to the Northern Gulf of Mexico annually, nutrient limitation of primary productivity still occurs offshore, acting as one of the major factors controlling local phytoplankton biomass and community structure. Bioassays were conducted for 48 hrs at two stations adjacent to the river plumes in April and August 2012. High Performance of Liquid Chromatography (HPLC) combined with ChemTax and a Fluorescence Induction and Relaxation (FIRe) system were combined to observe changes in the phytoplankton community structure and photosynthetic activity. Major fluorescence parameters (Fo, Fv/Fm) performed well to reveal the stimulating effect of the treatments with nitrogen (N-nitrate) and with nitrogen plus phosphate (+NPi). HPLC/ChemTax results showed that phytoplankton community structure shifted with nitrate addition: we observed an increase in the proportion of diatoms and prasinophytes and a decrease in cyanobacteria and prymnesiophytes. These findings are consistent with predictions from trait-based analysis which predict that phytoplankton groups with high maximum growth rates (?max ) and high nutrient uptake rates (Vmax ) readily take advantage of the addition of limiting nutrients. Changes in phytoplankton community structure, if persistent, could trigger changes of particular organic matter fluxes and alter the micro-food web cycles and bottom oxygen consumption. PMID:24551144

Zhao, Yan; Quigg, Antonietta

2014-01-01

220

Short-and long-term fertility trials in Colombia to determine the nutrient requirements of cassava  

Microsoft Academic Search

One-year simple NPK trials were conducted in 22 locations in four regions of Colombia to determine the response of cassava (Manihot esculenta Crantz) to N, P and K and to relate this response to the available P and K contents of the soil, as well as to the N, P, and K concentrations in youngest fully expanded leaf (YFEL) blades

R. H. Howeler; L. F. Cadavid

1990-01-01

221

Sources and fate of nutrients in a subtropical reservoir  

Microsoft Academic Search

This study examined the sources and fate of nutrient inputs from two principal tributaries to the eutrophic subtropical Wivenhoe\\u000a reservoir: an unregulated river and a dammed river with regular releases, during a period of declining reservoir water levels.\\u000a Nutrient budgets were constructed over a period of 6 years, and combined with short-term data on nutrient concentrations and\\u000a forms, and ?15N stable

Michele A. Burford; Susanne A. Green; Andrew J. Cook; Suzanne A. Johnson; Jason G. Kerr; Katherine R. O’Brien

222

The Role of Nutrient-Efficient Crops in Modern Agriculture  

Microsoft Academic Search

Nutrient-efficient crops have an important role in modern agriculture. In the low-input systems that characterize most of world agriculture, nutrient-efficient crops improve crop productivity. In high-input systems of the developed world, nutrient-efficient crops are valuable in reducing pollution of surface and ground water resources from intense fertilization. Recent developments in molecular biology, root biology, rhizosphere interactions, and modeling present new

Jonathan Lynch

1998-01-01

223

Organic matter stability and nutrient availability in Taupo Pumice  

Microsoft Academic Search

Soils derived from rhyolitic Taupo pumice when under permanent pasture accumulate organically bound nutrients in the top soil to a high degree. The available nutrient supply is thereby reduced.Respirometry studies show that this accumulation is not due to a reduced microbial activity resulting from a deficiency of a major or minor nutrient element.Raising the pH increases the microbial activity of

R. H. Jackman

1960-01-01

224

Enhanced Use of Feed and Manure Nutrients in Animal Agriculture  

Microsoft Academic Search

Whole-farm nutrient balances and animal:cropland ratios are used to asses overall pollution risks of livestock farms. These whole-farm indicators cannot address, however, how nutrient management in one production component (e.g., feed) may affect nutrient cycling in other production components (e.g., soils and crops) and the relative impact of each component's management on the environment. Many livestock operations rely on inexpensive

J. Mark Powell

225

Nutrient Excretion Rates of Anadromous Alewives during Their Spawning Migration  

Microsoft Academic Search

Excretion is one of the processes through which anadromous fishes move marine-derived nutrients into freshwater ecosystems, but no direct estimates of nutrient excretion rates by anadromous fish exist. We estimated the mass-specific nutrient excretion rates of anadromous alewives Alosa pseudoharengus during their spring spawning migration into Bride Lake, Connecticut. Anadromous alewives excreted an average of 2.17 ?g of phosphorus per

David M. Post; Annika W. Walters

2009-01-01

226

Physiological Growth Responses by Nutrient Interruption in Aeroponically Grown Potatoes  

Microsoft Academic Search

This study was conducted to retard potato (Solanum tuberosum L. cvs Superior, Atlantic, and Jasim) shoot growth by nutrient interruption and thereby induce tuber formation in an aeroponic\\u000a cultivation system. In the period between 25 and 55 days after transplanting (DAT), a 10-day nutrient interruption was carried\\u000a out on the potato plants. The interruption of nutrient supply significantly increased root activity

Dong Chil Chang; Choun Soo Park; Sung Yeul Kim; Su Jeong Kim; Yong Beom Lee

2008-01-01

227

Nutrient Pollution of Coastal Rivers, Bays, and Seas  

NSDL National Science Digital Library

This 'Issues in Ecology' article from the Ecological Society of America provides information about the consequences of nutrient enrichment along the US coast. It describes problems such as harmful algal blooms (HABs), anoxia, hypoxia, and dead zones. It explains which nutrients are involved and describes implications of excess nutrients in regions such as the Gulf of Mexico/Mississippi River basin. The article features several color photographs, maps, and diagrams.

Howarth, Robert; Anderson, Donald; Cloern, James; Elfring, Chris; Hopkinson, Charles; Lapointe, Brian

228

Nutrient fluxes and net metabolism in Lobos coastal lagoon, México  

Microsoft Academic Search

Fluxes of nutrients and net metabolism were estimated in coastal lagoon Lobos, a semi-arid subtropical lagoon from Gulf of California, Mexico. Sampling runs were carried out during summer and winter, seawater samples for nutrients were collected in coastal lagoon, offshore and a channel waste-water, physico-chemical parameters were measured in situ. Fluxes of nutrients and net metabolism were estimated using LOICZ

Valenzuela-Siu Mónica; Arreola-Lizárraga José Alfredo; Sánchez-Carrillo Salvador; Padilla-Arredondo Gustavo

2007-01-01

229

Nutrient Recommendations and Dietary Guidelines for Pregnant Women  

Microsoft Academic Search

The requirements for selected nutrients increase appreciably during pregnancy. The recommended intakes for the following nutrients\\u000a are >25% higher than are the amounts recommended for nonpregnant women: protein, ?-linolenic acid, iodine, iron, zinc, folate,\\u000a niacin, riboflavin, thiamin, and vitamin B6. The needs for protein, iron, folate, and vitamin B6 are about 50% higher. Good food sources of these nutrients are

Lorrene D. Ritchie; Janet C. King

230

Interactive effects of nutrient additions and predation on infaunal communities  

USGS Publications Warehouse

Nutrient additions represent an important anthropogenic stress on coastal ecosystems. At moderate levels, increased nutrients may lead to increased primary production and, possibly, to increased biomass of consumers although complex trophic interactions may modify or mask these effects. We examined the influence of nutrient additions and interactive effects of trophic interactions (predation) on benthic infaunal composition and abundances through small-scale field experiments in 2 estuaries that differed in ambient nutrient conditions. A blocked experimental design was used that allowed an assessment of direct nutrient effects in the presence and absence of predation by epibenthic predators as well as an assessment of the independent effects of predation. Benthic microalgal production increased with experimental nutrient additions and was greater when infaunal abundances were lower, but there were no significant interactions between these factors. Increased abundances of one infaunal taxa, Laeonereis culveri, as well as the grazer feeding guild were observed with nutrient additions and a number of taxa exhibited higher abundances with predator exclusion. In contrast to results from freshwater systems there were no significant interactive effects between nutrient additions and predator exclusion as was predicted. The infaunal responses observed here emphasize the importance of both bottom-up (nutrient addition and primary producer driven) and top-down (predation) controls in structuring benthic communities. These processes may work at different spatial and temporal scales, and affect different taxa, making observation of potential interactive effects difficult.

Posey, M. H.; Alphin, T. D.; Cahoon, L.; Lindquist, D.; Becker, M. E.

1999-01-01

231

The Plant Ionome Revisited by the Nutrient Balance Concept  

PubMed Central

Tissue analysis is commonly used in ecology and agronomy to portray plant nutrient signatures. Nutrient concentration data, or ionomes, belong to the compositional data class, i.e., multivariate data that are proportions of some whole, hence carrying important numerical properties. Statistics computed across raw or ordinary log-transformed nutrient data are intrinsically biased, hence possibly leading to wrong inferences. Our objective was to present a sound and robust approach based on a novel nutrient balance concept to classify plant ionomes. We analyzed leaf N, P, K, Ca, and Mg of two wild and six domesticated fruit species from Canada, Brazil, and New Zealand sampled during reproductive stages. Nutrient concentrations were (1) analyzed without transformation, (2) ordinary log-transformed as commonly but incorrectly applied in practice, (3) additive log-ratio (alr) transformed as surrogate to stoichiometric rules, and (4) converted to isometric log-ratios (ilr) arranged as sound nutrient balance variables. Raw concentration and ordinary log transformation both led to biased multivariate analysis due to redundancy between interacting nutrients. The alr- and ilr-transformed data provided unbiased discriminant analyses of plant ionomes, where wild and domesticated species formed distinct groups and the ionomes of species and cultivars were differentiated without numerical bias. The ilr nutrient balance concept is preferable to alr, because the ilr technique projects the most important interactions between nutrients into a convenient Euclidean space. This novel numerical approach allows rectifying historical biases and supervising phenotypic plasticity in plant nutrition studies.

Parent, Serge-Etienne; Parent, Leon Etienne; Egozcue, Juan Jose; Rozane, Danilo-Eduardo; Hernandes, Amanda; Lapointe, Line; Hebert-Gentile, Valerie; Naess, Kristine; Marchand, Sebastien; Lafond, Jean; Mattos, Dirceu; Barlow, Philip; Natale, William

2013-01-01

232

Imaging complex nutrient dynamics in mycelial networks.  

PubMed

Transport networks are vital components of multi-cellular organisms, distributing nutrients and removing waste products. Animal cardiovascular and respiratory systems, and plant vasculature, are branching trees whose architecture is thought to determine universal scaling laws in these organisms. In contrast, the transport systems of many multi-cellular fungi do not fit into this conceptual framework, as they have evolved to explore a patchy environment in search of new resources, rather than ramify through a three-dimensional organism. These fungi grow as a foraging mycelium, formed by the branching and fusion of threadlike hyphae, that gives rise to a complex network. To function efficiently, the mycelial network must both transport nutrients between spatially separated source and sink regions and also maintain its integrity in the face of continuous attack by mycophagous insects or random damage. Here we review the development of novel imaging approaches and software tools that we have used to characterise nutrient transport and network formation in foraging mycelia over a range of spatial scales. On a millimetre scale, we have used a combination of time-lapse confocal imaging and fluorescence recovery after photobleaching to quantify the rate of diffusive transport through the unique vacuole system in individual hyphae. These data then form the basis of a simulation model to predict the impact of such diffusion-based movement on a scale of several millimetres. On a centimetre scale, we have used novel photon-counting scintillation imaging techniques to visualize radiolabel movement in small microcosms. This approach has revealed novel N-transport phenomena, including rapid, preferential N-resource allocation to C-rich sinks, induction of simultaneous bi-directional transport, abrupt switching between different pre-existing transport routes, and a strong pulsatile component to transport in some species. Analysis of the pulsatile transport component using Fourier techniques shows that as the colony forms, it self-organizes into well demarcated domains that are identifiable by differences in the phase relationship of the pulses. On the centimetre to metre scale, we have begun to use techniques borrowed from graph theory to characterize the development and dynamics of the network, and used these abstracted network models to predict the transport characteristics, resilience, and cost of the network. PMID:18778429

Fricker, M D; Lee, J A; Bebber, D P; Tlalka, M; Hynes, J; Darrah, P R; Watkinson, S C; Boddy, L

2008-08-01

233

Nutrient Controls on Biocomplexity of Mangrove Ecosystems  

USGS Publications Warehouse

Mangrove forests are important coastal ecosystems that provide a variety of ecological and societal services. These intertidal, tree-dominated communities along tropical coastlines are often described as 'simple systems,' compared to other tropical forests with larger numbers of plant species and multiple understory strata; however, mangrove ecosystems have complex trophic structures, and organisms exhibit unique physiological, morphological, and behavioral adaptations to environmental conditions characteristic of the land-sea interface. Biogeochemical functioning of mangrove forests is also controlled by interactions among the microbial, plant, and animal communities and feedback linkages mediated by hydrology and other forcing functions. Scientists with the U.S. Geological Survey (USGS) at the National Wetlands Research Center are working to understand more fully the impact of nutrient variability on these delicate and important ecosystems.

McKee, Karen L.

2004-01-01

234

Choline: An Essential Nutrient for Public Health  

PubMed Central

Choline was officially recognized as an essential nutrient by the Institute of Medicine (IOM) in 1998. There is a significant variation in the dietary requirement for choline that can be explained by common genetic polymorphisms. Because of its wide-ranging roles in human metabolism, from cell structure to neurotransmitter synthesis, choline-deficiency is now thought to have an impact on diseases such as liver disease, atherosclerosis and possibly neurological disorders. Choline is found in a wide variety of foods. Egg yolks are the most concentrated source of choline in the American diet, providing 680 milligrams per 100 grams. Mean choline intakes for older children, men, women and pregnant women are far below the Adequate Intake established by the IOM. Given the importance of choline in a wide range of critical functions in the human body, coupled with less than optimal intakes among the population, dietary guidance should be developed to encourage the intake of choline-rich foods.

da Costa, Kerry-Ann

2009-01-01

235

Nutrient absorption by Aphidius ervi larvae.  

PubMed

It is well documented that in the model system Aphidius ervi Haliday (Hymenoptera, Braconidae)/Acyrthosiphon pisum (Harris) (Homoptera, Aphididae) host regulation by the parasitoid larva induces in the aphid haemolymph major changes of the titer of nutritional compounds such as proteins, acylglycerols and free amino acids, in order to meet the stage-specific demands of the developing larva. Since little is known about how the larva absorbs these mobilized nutritional resources, nutrient absorption by larval stages of A. ervi was studied. In 2nd instar larvae, leucine was ten-fold accumulated in the haemocoel, and tyrosine and glutamine two-fold. Glucose and fructose were readily absorbed and fructose was extensively metabolized by larval tissues. In 3rd instars, the presence of a number of larvae that did not ingest the incubation medium enabled us to determine the respective amounts of substrate absorbed by the epidermis and the midgut. An accumulation of leucine in the haemocoel was observed only when midgut cells were involved in absorption, while the amino acid concentration within body fluids never exceeded that of the incubation medium when the uptake was performed only by epidermal cells. The immunofluorescence analysis, the mutual inhibition exerted on labeled glucose or fructose uptakes by a 100-fold excess of the sugars and the strong inhibition of uptakes induced by 0.2mM cytochalasin B support the expression of facilitative GLUT2-like transporters in the apical and basal cell membranes of midgut epithelial cells. Taken together, these results prove that both midgut and epidermis are involved in nutrient absorption throughout the parasitoid development, that GLUT2 transporters are responsible for glucose and fructose uptakes and that the chemical gradient that favors the passive influx of the two sugars is maintained by their conversion to other substrates. PMID:16085087

Caccia, S; Leonardi, M G; Casartelli, M; Grimaldi, A; de Eguileor, M; Pennacchio, F; Giordana, B

2005-11-01

236

Tithonia diversifolia : variations in leaf nutrient concentration and implications for biomass transfer  

Microsoft Academic Search

Green leaf biomass of Tithonia diversifolia is high in nutrients and recognised as a potential source of nutrients for crops. We conducted a field survey in western Kenya to determine the variation in leaf nutrient concentrations in tithonia grown in naturalised hedges and agricultural fields, and to examine whether leaf nutrient concentrations were related to soil nutrient status. Leaf P

T. S. George; P. J. Gregory; J. S. Robinson; R. J. Buresh; B. A. Jama

2001-01-01

237

Biomass and nutrient distribution and their return of Casuarina equisetifolia inoculated with biofertilizers in farm land  

Microsoft Academic Search

An experiment was conducted to study the productivity, nutrient distribution and nutrient cycling of Casuarina equisetifolia Forst in farm forestry. Seedlings inoculated with different biofertilizers such as Azospirillum, Phosphobacterium, AM fungi and Frankia along with their combinations were planted in farmland. Growth, biomass, nutrient distribution, nutrient uptake and nutrient-return through litter were estimated 24 months after planting by harvesting the

K Rajendran; P Devaraj

2004-01-01

238

Porous tube plant nutrient delivery system development: A device for nutrient delivery in microgravity  

NASA Technical Reports Server (NTRS)

The Porous Tube Plant Nutrient Delivery Systems or PTPNDS (U.S. Patent #4,926,585) has been under development for the past six years with the goal of providing a means for culturing plants in microgravity, specifically providing water and nutrients to the roots. Direct applications of the PTPNDS include plant space biology investigations on the Space Shuttle and plant research for life support in the Space Station Freedom. In the past, we investigated various configurations, the suitability of different porous materials, and the effects of pressure and pore size on plant growth. Current work is focused on characterizing the physical operation of the system, examining the effects of solution aeration, and developing prototype configurations for the Plant Growth Unit (PGU), the flight system for the Shuttle mid-deck. Future developments will involve testing on KC-135 parabolic flights, the design of flight hardware and testing aboard the Space Shuttle.

Dreschel, T. W.; Brown, C. S.; Piastuch, W. C.; Hinkle, C. R.; Knott, W. M.

1994-01-01

239

The Mauna Loa environmental matrix: foliar and soil nutrients  

Microsoft Academic Search

The accumulation of total carbon, nitrogen, and phosphorus in soils, available soil nutrients, and foliar nutrients in the native dominant Metrosideros polymorpha were determined across a wide elevational range on 9 lava flows on Mauna Loa, Hawai'i. The flows included a young (2800 y) áá (rough surface texture) and pahoehoe (smooth) flow on the wet east and dry northwest side

Peter M. Vitousek; Gregory Aplet; Douglas Turner; John J. Lockwood

1992-01-01

240

Food and Nutrient Contribution of Breakfast to the Total Diet  

Microsoft Academic Search

LEARNING OUTCOME: To examine the role of breakfast in the diets of Americans including contribution to daily food and nutrient intake.The nutritional role of breakfast in American diets was examined by computing mean food and nutrient intakes from breakfast and the total diet, from food intake records from the USDA's 1994 Continuing Survey of Food Intakes by Individuals. The study

S. A. Bowman

1997-01-01

241

Proposed recommended nutrient densities for moderately malnourished children  

Microsoft Academic Search

Recommended Nutrient Intakes (RNIs) are set for healthy individuals living in clean environments. There are no gen- erally accepted RNIs for those with moderate malnutrition, wasting, and stunting, who live in poor environments. Two sets of recommendations are made for the dietary intake of 30 essential nutrients in children with moderate malnutri- tion who require accelerated growth to regain normality:

Michael H. Golden

2009-01-01

242

BENTHIC NUTRIENT FLUX IN A SMALL ESTUARY IN NORTHWESTERNFLORIDA (USA)  

EPA Science Inventory

Benthic Nutrient Flux in a Small Estuary in Northwestern Florida(USA).Gulf and Caribbean Research 18, 15-25, 2006. Benthic nutrient fluxes of ammonium (NH4+), nitrite/nitrate (NO2-+NO3-), phosphate (PO4-), and dissolved silica (DSi) were measured in Escambia Bay, an estuar...

243

Nutrient-limited microbial growth kinetics: overview and recent advances  

Microsoft Academic Search

Traditional concepts of nutrient uptake and growth kinetics as linked by cell yield are presented. Phenomena affecting the kinetics are examined along with a discussion of those which lead to ambiguity. Concepts of flux control are presented to help understand the distribution of material along metabolic pathways. Specific affinity is described to relate nutrient accumulation rates to transporter density. It

D. K. Button

1993-01-01

244

Approaches for Development of Nutrient Criteria in Oregon Estuaries  

EPA Science Inventory

Development of nutrient criteria for all water body types of the US remains a top priority for EPA. Estuaries in the Pacific Northwest receive nutrients from both the watershed and the coastal ocean, and thus are particularly complex systems in which to establish water quality c...

245

NUTRIENT CONTENT OF THE FOOD SUPPLY, 1909 - 1999  

EPA Science Inventory

Under Secretary Shirley Watkins the publication the "Nutrient Content of the U.S. Food Supply, 1909-94" was released. It was prepared by the USDA Center for Nutrition Policy and Promotion and presents historical data on the nutrient content of the U.S. food supply through 1994, w...

246

Using Soil Electrical Conductivity to Improve Nutrient Management  

Microsoft Academic Search

ECa could be used to measure the available nutrient content of the soil, eliminating the need for time-consum- While site-specific nutrient management has the potential for im- ing and expensive soil sample acquisition and analysis. proving crop yields, the cost of intensive soil sampling is usually greater Apparent soil electrical conductivity consists of two than the benefits gained. Apparent soil

Ronnie W. Heiniger; Robert G. McBride; David E. Clay

2003-01-01

247

Nutrients' removal from aquaculture wastewater using the macroalgae Gracilaria birdiae  

Microsoft Academic Search

Intensive aquaculture releases large amount of nutrients into aquatic ecosystems and can lead to eutrophication of coastal waters. Studies conducted in aquaculture systems have demonstrated that the seaweeds are efficient in reducing nutrients and at the same time provides extra income, when species of economic importance are used. This study was conducted to evaluate whether Gracilaria birdiae could be cultivated

E. Marinho-Soriano; S. O. Nunes; M. A. A. Carneiro; D. C. Pereira

2009-01-01

248

Nutrient quality of fast food kids meals1-4  

Microsoft Academic Search

Background: Exposure of children to kids meals at fast food res- taurants is high; however, the nutrient quality of such meals has not been systematically assessed. Objective: We assessed the nutrient quality of fast food meals marketed to young children, ie, \\

Sharon I O'Donnell; Sharon L Hoerr; Jason A Mendoza; Eugenia Tsuei Goh

249

Nutrient availability and cocoyam yield under different tillage practices  

Microsoft Academic Search

Research information on the effect of tillage systems on cocoyam (Xanthosoma sagittifolium (L.) Schott) growth, nutrient status and yield is lacking in Africa. The effects of zero tillage with mulch, zero tillage without mulch, manual mounding, manual ridging and conventional tillage on cocoyam yield, growth and nutrient availability were compared during 2 years on an Alfisol (Oxic Tropuldaf) at Owo

T. M. Agbede

2008-01-01

250

Estimation of postfire nutrient loss in the Florida everglades.  

PubMed

Postfire nutrient release into ecosystem via plant ash is critical to the understanding of fire impacts on the environment. Factors determining a postfire nutrient budget are prefire nutrient content in the combustible biomass, burn temperature, and the amount of combustible biomass. Our objective was to quantitatively describe the relationships between nutrient losses (or concentrations in ash) and burning temperature in laboratory controlled combustion and to further predict nutrient losses in field fire by applying predictive models established based on laboratory data. The percentage losses of total nitrogen (TN), total carbon (TC), and material mass showed a significant linear correlation with a slope close to 1, indicating that TN or TC loss occurred predominantly through volatilization during combustion. Data obtained in laboratory experiments suggest that the losses of TN, TC, as well as the ratio of ash total phosphorus (TP) concentration to leaf TP concentration have strong relationships with burning temperature and these relationships can be quantitatively described by nonlinear equations. The potential use of these nonlinear models relating nutrient loss (or concentration) to temperature in predicting nutrient concentrations in field ash appear to be promising. During a prescribed fire in the northern Everglades, 73.1% of TP was estimated to be retained in ash while 26.9% was lost to the atmosphere, agreeing well with the distribution of TP during previously reported wild fires. The use of predictive models would greatly reduce the cost associated with measuring field ash nutrient concentrations. PMID:19643746

Qian, Y; Miao, S L; Gu, B; Li, Y C

2009-01-01

251

Reference Condition Approach for Numeric Nutrient Criteria for Oregon Estuaries  

EPA Science Inventory

Development of nutrient criteria for all water body types of the US remains a top priority for EPA. Estuaries in the Pacific Northwest receive nutrients from both the watershed and the coastal ocean, and thus are particularly complex systems in which to establish water quality c...

252

Contribution of agroforestry trees to nutrient requirements of intercropped plants  

Microsoft Academic Search

A major tenet of agroforestry, that trees maintain soil fertility, is based primarily on observations of higher crop yields near trees or where trees were previously grown. Recently objective analyses and controlled experiments have addressed this topic. This paper examines the issues of tree prunings containing sufficient nutrients to meet crop demands, the timing of nutrient transfer from decomposition to

C. A. Palm

1995-01-01

253

Mariculture: significant and expanding cause of coastal nutrient enrichment  

NASA Astrophysics Data System (ADS)

Mariculture (marine aquaculture) generates nutrient waste either through the excretion by the reared organisms, or through direct enrichment by, or remineralization of, externally applied feed inputs. Importantly, the waste from fish or shellfish cannot easily be managed, as most is in dissolved form and released directly to the aquatic environment. The release of dissolved and particulate nutrients by intensive mariculture results in increasing nutrient loads (finfish and crustaceans), and changes in nutrient stoichiometry (all mariculture types). Based on different scenarios, we project that nutrients from mariculture will increase up to six fold by 2050 with exceedance of the nutrient assimilative capacity in parts of the world where mariculture growth is already rapid. Increasing nutrient loads and altered nutrient forms (increased availability of reduced relative to oxidized forms of nitrogen) and/or stoichiometric proportions (altered nitrogen:phosphorus ratios) may promote an increase in harmful algal blooms (HABs) either directly or via stimulation of algae on which mixotrophic HABs may feed. HABs can kill or intoxicate the mariculture product with severe economic losses, and can increase risks to human health.

Bouwman, Lex; Beusen, Arthur; Glibert, Patricia M.; Overbeek, Ciska; Pawlowski, Marcin; Herrera, Jorge; Mulsow, Sandor; Yu, Rencheng; Zhou, Mingjiang

2013-12-01

254

Soil Nutrient Composition in Afromontane Forests of Northern Ethiopia  

Microsoft Academic Search

Deforestation in the northern highlands of Ethiopia has left 35,000 forest fragments ranging in size from 3 to 300 ha (Bongers et al 2006). Deforestation produces edges which increase disturbance within the forest such as decreased water availability and increased light. To determine the degree of these edge effects and the nutrient status of these forests, I analyzed the nutrient

Maria Baimas-George

2012-01-01

255

Insights into Digestion and Absorption of Major Nutrients in Humans  

ERIC Educational Resources Information Center

Nutrient digestion and absorption is necessary for the survival of living organisms and has evolved into the complex and specific task of the gastrointestinal (GI) system. While most people simply assume that their GI tract will work properly to use nutrients, provide energy, and release wastes, few nonscientists know the details about how various…

Goodman, Barbara E.

2010-01-01

256

Nutrient dynamics in Amazon shelf waters: results from AMASSEDS  

Microsoft Academic Search

Four hydrographic cruises were conducted on the Amazon shelf as part of the AMASSEDS field program. During each cruise, approximately 55 stations were occupied and nutrients, as well as other hydrographic parameters, were measured. The results of this time series sampling program indicate that the nutrient concentrations in the riverine end-member (silicate = 144 ?mol kg?1, phosphate = 0.7 ?mol

David J. Demaster; Robert H. Pope

1996-01-01

257

Medication-Nutrient Interactions and Individuals with Special Healthcare Needs  

ERIC Educational Resources Information Center

Many children and adults with special healthcare needs receive one or more medications on a regular basis. Parents and healthcare professionals who care for these individuals should be aware of each medication and potential interactions with foods/nutrients. Those who require long term or multiple medications are at highest risk for drug-nutrient

Brizee, Lori S.

2008-01-01

258

Delineating soil nutrient management zones based on ID3 algorithm  

Microsoft Academic Search

Focused on the contents of organic matter, total N, available P and available K in patch data of Dehui city, Jilin Province, this paper studies on soil nutrient management zones using decision tree ID3 algorithm. By experimental analysis, we obtain six partitions and the result shows that sub-area differences in soil nutrient content are similar or less significant but differences

Liu He; Cao Liying; Chen Guifen; Li Dexin

2011-01-01

259

Delayed Release Nutrient Supplement for Mushroom Culture 1  

PubMed Central

The disadvantages associated with the supplementation of noncomposted nutrients to mushroom compost at spawning were largely overcome by encapsulating microdroplets of vegetable oil within a protein coat that was denatured with formaldehyde. Increases in mushroom yield of 60% were obtained. Delayed nutrient release was indicated by prolonged stimulation of yields beyond the first few flushes.

Carroll, A. D.; Schisler, L. C.

1976-01-01

260

Nutrient composition and protein quality of minor millets  

Microsoft Academic Search

Nutrient composition of five minor millets produced and consumed in dry land regions and tribal areas of Andhra Pradesh, India, was evaluated. The millets analysed were Italian millet (Setaria Italica), French millet (Panicum miliaceum), Barnyard millet (Echinachloa colona), Kodo millet (Paspalum scrobiculatum) and little millet (Panicum miliare). The nutrients analysed were proximate principles, amino acids, fibre components, calcium, Phosphorus and

Pasala Geervani; Bjorn O. Eggum

1989-01-01

261

Analysis of nutrient flows in integrated intensive aquaculture systems  

Microsoft Academic Search

This paper analyses nutrient conversions, which are taking place in integrated intensive aquaculture systems. In these systems fish is cultured next to other organisms, which are converting otherwise discharged nutrients into valuable products. These conversions are analyzed based on nitrogen and phosphorous balances using a mass balance approach. The analytical concept of this review comprises a hypothetical system design with

O. Schneider; V. Sereti; E. H. Eding; J. A. J. Verreth

2005-01-01

262

The Coupling of Solution Chemistry to Plant Nutrient Demand in an on Demand Nutrient Delivery System  

NASA Technical Reports Server (NTRS)

The goal of the proposal will be to determine the suitability of the DASI instrument in providing a signal that can be recognized and be utilized as an indicator of plant stress. The method to be utilized for evaluating stress is the presentation of an every increasing level of nutrient deficiency and salinity stress (addition of salt (NACl) or increasing concentration of balanced nutrient) while simultaneously recording spectral reflectance using the DASI instrument and monitoring the traditional processes of gas exchange and nutrient uptake parameters. In this manner, we will be able to directly compare the DASI measurements with known stresses as determined by the traditional gas exchange and nutrient uptake measures of stress. We anticipate that the DASI will provide a sensitive identifier of plant stress; recording signals of the resulting changes in plant metabolism in real time, far before any visible effects of stress could be observed. Thus, there is a potential for very early management intervention to correct a stress condition before damage could develop. The present response time for the observation of visual symptoms of plant stress is considerable and only provides an indication that a stress is present after it has been present for an extended period of time. Thus, the impact of a plant-based life support function will have already been significant. An additional benefit of this research to regenerative life support will be the characterization of a potential recovery scenario from various degrees of stress. The experimental approach to be employed includes the removal of the stress at various points in the stress gradient and the characterization of plant performance and reflectance spectra during recovery from various degrees of stress. Spectral reflectance imaging techniques have been developed and used to measure the biochemical composition of plants and relate these characteristics to the fluxes of biochemical elements within the ecosystem.

Savage, Wayne

1998-01-01

263

Linkages between nutrients and assemblages of macroinvertebrates and fish in wadeable streams: Implication to nutrient criteria development  

USGS Publications Warehouse

We sampled 240 wadeable streams across Wisconsin for different forms of phosphorus and nitrogen, and assemblages of macroinvertebrates and fish to (1) examine how macroinvertebrate and fish measures correlated with the nutrients; (2) quantify relationships between key biological measures and nutrient forms to identify potential threshold levels of nutrients to support nutrient criteria development; and (3) evaluate the importance of nutrients in influencing biological assemblages relative to other physicochemical factors at different spatial scales. Twenty-three of the 35 fish and 18 of the 26 macroinvertebrate measures significantly correlated (P < 0.05) with at least one nutrient measure. Percentages of carnivorous, intolerant, and omnivorous fishes, index of biotic integrity, and salmonid abundance were fish measures correlated with the most nutrient measures and had the highest correlation coefficients. Percentages of Ephemeroptera-Plecoptera-Trichoptera individuals and taxa, Hilsenhoff biotic index, and mean tolerance value were macroinvertebrate measures that most strongly correlated with the most nutrient measures. Selected biological measures showed clear trends toward degradation as concentrations of phosphorus and nitrogen increased, and some measures showed clear thresholds where biological measures changed drastically with small changes in nutrient concentrations. Our selected environmental factors explained 54% of the variation in the fish assemblages. Of this explained variance, 46% was attributed to catchment and instream habitat, 15% to nutrients, 3% to other water quality measures, and 36% to the interactions among all the environmental variables. Selected environmental factors explained 53% of the variation in macroinvertebrate assemblages. Of this explained variance, 42% was attributed to catchment and instream habitat, 22% to nutrients, 5% to other water quality measures, and 32% to the interactions among all the environmental variables. ?? 2006 Springer Science+Business Media, Inc.

Wang, L.; Robertson, D. M.; Garrison, P. J.

2007-01-01

264

Nutrient budgets for large Chinese estuaries and embayment  

NASA Astrophysics Data System (ADS)

Nutrient concentrations among the Chinese rivers and bays vary 10-75 fold depending on nutrient elements. The silicic acid levels in South China rivers are higher than those from North China rivers and the yields of dissolved silicate increased from the north to the south of China, indicating the effect of climate on weathering. The nutrient levels in Chinese rivers are higher than those from the large and less-disturbed world rivers such as Amazon and Zaire, but comparable to the values for European and North American polluted and eutrophic rivers like the Loire and Po. This may be ascribed to both of extensive leaching and influences from agricultural and domestic activities over the drainage basins of Chinese rivers. DIN:PO3-4 ratios in most of Chinese rivers and bays are higher (up to 2800) than the other rivers in the world. The atomic ratios of DIN to PO43- in the major Chinese rivers and embayment decrease in exponential trend with increase in the atomic ratios of PO43- to Si(OH)4, indicating that primary production in coastal environments changes with the nutrients transport when the urbanization develops to a certain extent, and the potential limited nutrient elements can be changed from phosphorus to nitrogen limitation, which can modify aquatic food webs and then the ocean ecosystem. A simple steady-state mass-balance box model was employed. The output shows that the estuaries and embayment behave as a sink or source of nutrients. For the major Chinese estuaries, both residual and mixing flow transport nutrients off the estuaries, and nutrient transport fluxes in summer is 3-4 fold that in winter except comparable for NH4+. These fluxes are 1.0-1.7 fold that estimated by timing riverine nutrient concentrations and freshwater discharge. For the major Chinese embayment, nutrient elements are transported to China Seas except PO43- and Si(OH)4 in Sanggou Bay and Jiaozhou Bay. Seasonally, nutrients transport fluxes off the bays in the summer are 2.2-7.0 fold that in the winter. In the embayment, the exchange flow dominated the water budgets, resulting in average system salinity approaching the China seas salinity where river discharge is limited. The major Chinese estuaries and embayment transport 1.0-3.1% of nitrogen, 0.2-0.5% of phosphorus and 3% of silicon necessary for phytoplankton growth for the China Seas. This demonstrates regenerated nutrients in water column and sediments and nutrients transport fluxes between the China Seas and open ocean play an important role for phytoplankton growth. Atmospheric deposition may be another important source of nutrients for the China Seas.

Liu, S. M.; Hong, G.-H.; Ye, X. W.; Zhang, J.; Jiang, X. L.

2009-01-01

265

Excess nutrients in hydroponic solutions alter nutrient content of rice, wheat, and potato  

NASA Technical Reports Server (NTRS)

Environment has significant effects on the nutrient content of field-grown crop plants. Little is known, however, about compositional changes caused by controlled environments in which plants receive only artificial radiation and soilless, hydroponic culture. This knowledge is essential for developing a safe, nutritious diet in a Controlled Ecological Life-Support System (CELSS). Three crops that are candidates for inclusion in a CELSS (rice, wheat, and white potato) were grown both in the field and in controlled environments where the hydroponic nutrient solution, photosynthetic photon flux (PPF), and CO2 level were manipulated to achieve rapid growth rates. Plants were harvested at maturity, separated into discrete parts, and dried prior to analysis. Plant materials were analyzed for proximate composition (protein, fat, ash, and carbohydrate), total nitrogen (N), nitrate, minerals, and amino-acid composition. The effect of environment on nutrient content varied by crop and plant part. Total N and nonprotein N (NPN) contents of plant biomass generally increased under controlled-environment conditions compared to field conditions, especially for leafy plant parts and roots. Nitrate levels were increased in hydroponically-grown vegetative tissues, but nitrate was excluded from grains and tubers. Mineral content changes in plant tissue included increased phosphorus and decreased levels of certain micronutrient elements under controlled-environment conditions. These findings suggest that cultivar selection, genetic manipulation, and environmental control could be important to obtain highly nutritious biomass in a CELSS.

McKeehen, J. D.; Mitchell, C. A.; Wheeler, R. M.; Bugbee, B.; Nielsen, S. S.

1996-01-01

266

Excess nutrients in hydroponic solutions alter nutrient content of rice, wheat, and potato  

NASA Astrophysics Data System (ADS)

Environment has significant effects on the nutrient content of field-grown crop plants. Little is known, however, about compositional changes caused by controlled environments in which plants receive only artificial radiation and soilless, hydroponic culture. This knowledge is essential for developing a safe, nutritious diet in a Controlled Ecological Life-Support System (CELSS). Three crops that are candidates for inclusion in a CELSS (rice, wheat, and white potato) were grown both in the field and in controlled environments where the hydroponic nutrient solution, photosynthetic photon flux (PPF), and CO_2 level were manipulated to achieve rapid growth rates. Plants were harvested at maturity, separated into discrete parts, and dried prior to analysis. Plant materials were analyzed for proximate composition (protein, fat, ash, and carbohydrate), total nitrogen (N), nitrate, minerals, and amino-acid composition. The effect of environment on nutrient content varied by crop and plant part. Total N and nonprotein N (NPN) contents of plant biomass generally increased under controlled-environment conditions compared to field conditions, especially for leafy plant parts and roots. Nitrate levels were increased in hydroponically-grown vegetative tissues, but nitrate was excluded from grains and tubers. Mineral content changes in plant tissue included increased phosphorus and decreased levels of certain micronutrient elements under controlled-environment conditions. These findings suggest that cultivar selection, genetic manipulation, and environmental control could be important to obtain highly nutritious biomass in a CELSS.

McKeehen, J. D.; Mitchell, C. A.; Wheeler, R. M.; Bugbee, B.; Nielsen, S. S.

267

Drug-nutrient interactions: a case and clinical guide.  

PubMed

Advances in pharmacokinetics and pharmacodynamics require new competencies related to pharmaceutical prescribing. First, both physicians and pharmacists need to recognize the potential negative impact of nutrients and dietary supplements on the absorption, metabolism, and utilization of prescription drugs. Second, physicians, even more than pharmacists, need to recognize the potential negative effects of pharmaceuticals on the absorption, metabolism, and utilization of nutrients. This article discusses common drug-nutrient interactions and presents a case that illustrates how unrecognized nutrient disruption may negatively affect a patient's health and potentially result in unnecessary prescribing of medications. In presenting the case, we also provide a conceptual framework for assessing and treating this patient and a summary of current knowledge regarding drug-nutrient interactions. PMID:23256289

Plotnikoff, Gregory A

2011-10-01

268

Influence of Predeprivation Diet Nutrient Density and Sodium Chloride Content on Nutrient Losses and Repletion in Lambs1,2,3  

Microsoft Academic Search

Six crossbred lambs (32 ± 2 kg) in a 6 × 6 Latin square design were used to determine the effects of predeprivation diet nutrient density and NaCl content on nutrient losses during periods of feed and water deprivation and nutrient repletion. Treat- ments consisted of two predeprivation dietary nutrient densities (low (LOW) and moderate (MOD)) and three NaCl intakes

N. A. Cole

269

Nutrient vectors and riparian nutrient processing in African semiarid savanna ecosystems  

USGS Publications Warehouse

This review article describes vectors for nitrogen and phosphorus delivery to riparian zones in semiarid African savannas, the processing of nutrients in the riparian zone and the effect of disturbance on these processes. Semiarid savannas exhibit sharp seasonality, complex hillslope hydrology and high spatial heterogeneity, all of which ultimately impact nutrient fluxes between riparian, upland and aquatic environments. Our review shows that strong environmental drivers such as fire and herbivory enhance nitrogen, phosphorus and sediment transport to lower slope positions by shaping vegetative patterns. These vectors differ significantly from other arid and semiarid ecosystems, and from mesic ecosystems where the impact of fire and herbivory are less pronounced and less predictable. Also unique is the presence of sodic soils in certain hillslopes, which substantially alters hydrological flowpaths and may act as a trap where nitrogen is immobilized while sediment and phosphorus transport is enhanced. Nutrients and sediments are also deposited in the riparian zone during seasonal, intermittent floods while, during the dry season, subsurface movement of water from the stream into riparian soils and vegetation further enrich riparian zones with nutrients. As is found in mesic ecosystems, nutrients are immobilized in semiarid riparian corridors through microbial and plant uptake, whereas dissimilatory processes such as denitrification may be important where labile nitrogen and carbon are in adequate supply and physical conditions are suitablea??such as in seeps, wallows created by animals, ephemeral wetlands and stream edges. Interaction between temporal hydrologic connectivity and spatial heterogeneity are disrupted by disturbances such as large floods and extended droughts, which may convert certain riparian patches from sinks to sources for nitrogen and phosphorus. In the face of increasing anthropogenic pressure, the scientific challenges are to provide a basic understanding of riparian biogeochemistry in semiarid African savannas to adequately address the temporal and spatial impact of disturbances, and to apply this knowledge to better regional land and water management. An integrated, multidisciplinary approach applied in protected as well as human-disturbed ecosystems in southern Africa is essential for underpinning a strong environmental basis for sustainable human-related expansion.

Jacobs, Shayne M.; Bechtold, J. S.; Biggs, H. C.; Grimm, N. B.; McClain, M. E.; Naiman, R. J.; Perakis, Steven S.; Pinay, G.; Scholes, M. C.

2007-01-01

270

Comparison of Nutrient Content and Cost of Home-Packed Lunches to Reimbursable School Lunch Nutrient Standards and Prices  

ERIC Educational Resources Information Center

Purpose: The purpose of this study was to compare nutrient content and cost of home-packed lunches to nutrient standards and prices for reimbursable school lunches. Methods: Researchers observed food and beverage contents of 333 home packed lunches at four north Texas elementary schools. Nutritionist Pro was used to analyze lunches for calories,…

Johnson, Cara M.; Bednar, Carolyn; Kwon, Junehee; Gustof, Alissa

2009-01-01

271

Significant Groundwater Discharge of Nutrients to Western Long Island Sound Inferred From Radioisotope, Nutrient and Organic Geochemical Tracers  

Microsoft Academic Search

Western Long Island Sound suffers from seasonal oxygen depletion due to both nutrient loading in this heavily populated region as well as restricted circulation of the Sound. The role played by groundwater in delivering nutrients to the Sound is not well understood, which served as motivation for the sampling we initiated in May, 2008. Work was carried out in both

J. Crusius; K. D. Kroeger; P. Zhang; S. Zhao; J. F. Bratton; H. Bokuniewicz; R. Coffey; A. Green; S. Baldwin; L. Erban; M. Casso

2008-01-01

272

Changes in the nutrient composition of Tetraselmis suecica cultured semicontinuously with different nutrient concentrations and renewal rates  

Microsoft Academic Search

The marine microalga Tetraselmis suecica was cultured semicontinuously with two nutrient concentrations: 2 and 4 mmol N l?1 and five rates of daily renewal of the culture media in the range 10–50%, in order to study the changes in the nutrient composition of the cells produced under such conditions. An increase in the renewal rate produced an increase in protein

Ana Otero; Jaime Fábregas

1997-01-01

273

INTERACTIVE EFFECT OF NUTRIENT CONCENTRATION AND CONTAINER VOLUME ON FLOWERING, FRUITING, AND NUTRIENT UPTAKE OF SWEET PEPPER  

Microsoft Academic Search

Flower abortion and low fruit set has long been a problem in sweet pepper (Capsicum annum L.), especially when the flowers are cross-pollinated. Restrictions of nutrient element supply and root volume affect plant vigor and size. To study the interactive effects of nutrient element supply and container volume on pepper flowering and fruiting, a complete interactive experiment (3 × 3)

Guohua Xu; S. Wolf; Uzi Kafkafi

2001-01-01

274

EFFECTS OF ROOT ZONE PH AND NUTRIENT CONCENTRATION ON THE GROWTH AND NUTRIENT UPTAKE OF TOMATO SEEDLINGS  

Microsoft Academic Search

The effects of nutrient concentration and pH, two major chemical properties of soil, on plant responses were investigated with seedlings of tomato, which is widely grown in greenhouses, as the model plant. An experiment with four levels of nutrient concentration [None (NC 0), 1 (NC 1), 5 (NC 5), and 10 folds (NC 10)], in combination with three pH levels

Yun-Im Kang; Jin-Myeon Park; Seung-Heui Kim; Nam-Jun Kang; Kyoung-Sub Park; Si-Young Lee; Byoung Ryong Jeong

2011-01-01

275

Nutrient management effects on sweetpotato genotypes under controlled environment  

NASA Technical Reports Server (NTRS)

Sweetpotato is one of several crops recommended by National Aeronautics and Space Administration (NASA) for bioregenerative life support studies. One of the objectives of the Tuskegee University NASA Center is to optimize growth conditions for adaptability of sweetpotatoes for closed bioregenerative systems. The role of nutrient solution management as it impacts yield has been one of the major thrusts in these studies. Nutrient solution management protocol currently used consists of a modified half Hoagland solution that is changed at 14-day intervals. Reservoirs are refilled with deionized water if the volume of the nutrient solution was reduced to 8 liters or less before the time of solution change. There is the need to recycle and replenish nutrient solution during crop growth, rather than discard at 14 day intervals as previously done, in order to reduce waste. Experiments were conducted in an environmental growth room to examine the effects of container size on the growth of several sweetpotato genotypes grown under a nutrient replenishment protocol. Plants were grown from vine cuttings of 15cm length and were planted in 0.15 x 0.15 x 1.2m growth channels using a closed nutrient film technique system. Nutrient was supplied in a modified half strength Hoagland's solution with a 1:2.4 N:K ratio. Nutrient replenishment protocol consisted of daily water replenishment to a constant volume of 30.4 liters in the small containers and 273.6 liters in the large container. Nutrients were replenished as needed when the EC of the nutrient solution fell below 1200 mhos/cm. The experimental design used was a split-plot with the main plot being container size and genotypes as the subplot. Nine sweetpotato genotypes were evaluated. Results showed no effect of nutrient solution container size on storage root yield, foliage fresh and dry mass, leaf area or vine length. However, plants grown using the large nutrient solution container accumulated more storage root dry mass than those with the small containers. Although plants grown with the smaller containers showed greater water uptake, plant nutrient uptake was lower than with the larger container. All genotypes evaluated showed variation in their responses to all parameters measured.

David, P. P.; Bonsi, C. K.; Trotman, A. A.; Douglas, D. Z.

1996-01-01

276

Nutrient management effects on sweetpotato genotypes under controlled environment.  

PubMed

Sweetpotato is one of several crops recommended by National Aeronautics and Space Administration (NASA) for bioregenerative life support studies. One of the objectives of the Tuskegee University NASA Center is to optimize growth conditions for adaptability of sweetpotatoes for closed bioregenerative systems. The role of nutrient solution management as it impacts yield has been one of the major thrusts in these studies. Nutrient solution management protocol currently used consists of a modified half Hoagland solution that is changed at 14-day intervals. Reservoirs are refilled with deionized water if the volume of the nutrient solution was reduced to 8 liters or less before the time of solution change. There is the need to recycle and replenish nutrient solution during crop growth, rather than discard at 14 day intervals as previously done, in order to reduce waste. Experiments were conducted in an environmental growth room to examine the effects of container size on the growth of several sweetpotato genotypes grown under a nutrient replenishment protocol. Plants were grown from vine cuttings of 15cm length and were planted in 0.15 x 0.15 x 1.2m growth channels using a closed nutrient film technique system. Nutrient was supplied in a modified half strength Hoagland's solution with a 1:2.4 N:K ratio. Nutrient replenishment protocol consisted of daily water replenishment to a constant volume of 30.4 liters in the small containers and 273.6 liters in the large container. Nutrients were replenished as needed when the EC of the nutrient solution fell below 1200 mhos/cm. The experimental design used was a split-plot with the main plot being container size and genotypes as the subplot. Nine sweetpotato genotypes were evaluated. Results showed no effect of nutrient solution container size on storage root yield, foliage fresh and dry mass, leaf area or vine length. However, plants grown using the large nutrient solution container accumulated more storage root dry mass than those with the small containers. Although plants grown with the smaller containers showed greater water uptake, plant nutrient uptake was lower than with the larger container. All genotypes evaluated showed variation in their responses to all parameters measured. PMID:11541588

David, P P; Bonsi, C K; Trotman, A A; Douglas, D Z

1996-12-01

277

SUSPENDED AND BENTHIC SEDIMENT RELATIONSHIPS IN THE YAQUINA ESTUARY, OREGON: NUTRIENT PROCESSING  

EPA Science Inventory

Measurements of nutrient loading and subsequent nutrient processing are fundamental for determining biogeochemical processes in rivers and estuaries. In Oregon coastal watersheds, nutrient transport is strongly seasonal with up to 94% of the riverine dissolved nitrate and silic...

278

Nutrient enrichment affects the mechanical resistance of aquatic plants  

PubMed Central

For many plant species, nutrient availability induces important anatomical responses, particularly the production of low-density tissues to the detriment of supporting tissues. Due to the contrasting biomechanical properties of plant tissues, these anatomical responses may induce important modifications in the biomechanical properties of plant organs. The aim of this study was to determine the effects of nutrient enrichment on the anatomical traits of two freshwater plant species and its consequences on plant biomechanical performance. Two plant species were grown under controlled conditions in low versus high nutrient levels. The anatomical and biomechanical traits of the plant stems were measured. Both species produced tissues with lower densities under nutrient-rich conditions, accompanied by modifications in the structure of the aerenchyma for one species. As expected, nutrient enrichment also led to important modifications in the biomechanical properties of the stem for both species. In particular, mechanical resistance (breaking force and strength) and stiffness of stems were significantly reduced under nutrient rich conditions. The production of weaker stem tissues as a result of nutrient enrichment may increase the risk of plants to mechanical failure, thus challenging plant maintenance in mechanically stressful or disturbed habitats.

Puijalon, Sara

2012-01-01

279

Linkages between hydrogeomorphology and nutrient availability in wetlands (Invited)  

NASA Astrophysics Data System (ADS)

Hydrogeomorphology is an important determinant of nutrient transport, cycling, and availability in wetlands. Fluvial geomorphic position in the landscape can influence the connectivity of wetlands to flowing water, thereby affecting the inputs of nutrients to the wetland, and ultimately controlling biogeochemical transformations. Similarly, internal geomorphic heterogeneity (microtopography) can influence soil wetness within the wetland and biogeochemistry. Nitrogen (N) and phosphorus (P) inputs and soil biogeochemical transformations were measured across a range of wetland ecosystems, including floodplain wetlands, tidal freshwater wetlands, and created wetlands. Nitrogen and P inputs from sedimentation and inorganic ion loading to the soil surface were greater at locations with greater connectivity to river water. Nutrient inputs from sedimentation also vary across broad landscape gradients from nontidal, tidal freshwater, and tidal oligohaline wetlands. Both N and P mineralization in wetland soils increased with N and P inputs. Thus, greater hydrologic connectivity (as influenced by landscape position and river-wetland geomorphology) stimulates nutrient availability for primary production, other biogeochemical processes, and ecosystem nutrient retention. Furthermore, microtopographic heterogeneity within wetlands stimulated nutrient availability and retention. In tidal freshwater wetlands, hummocks were hotspots of soil nitrification relative to low lying hollows. In created wetlands, building microtopography during construction resulted in greater soil nitrification and denitrification. In conclusion, geomorphology and hydrology at multiple scales influence the inputs, biogeochemical transformations, and availability of nutrients in wetland ecosystems.

Noe, G. B.; Hupp, C. R.; Schenk, E.; Batson, J.; Krauss, K.; Ensign, S.; Wolf, K.; Ahn, C.

2013-12-01

280

The Mauna Loa environmental matrix: foliar and soil nutrients  

USGS Publications Warehouse

The accumulation of total carbon, nitrogen, and phosphorus in soils, available soil nutrients, and foliar nutrients in the native dominant Metrosideros polymorpha were determined across a wide elevational range on 9 lava flows on Mauna Loa, Hawai'i. The flows included a young (2800 y) a??a?? (rough surface texture) and pa??hoehoe (smooth) flow on the wet east and dry northwest side of the mountain. Soil element pools and nutrient availability increased with flow age independent of climate. The dry sites accumulated organic matter and nutrients more slowly than comparable wet sites, but relative nutrient availability to plants (as indicated by soil assays and foliar nutrients) was greater in the dry sites. Accumulation of soil organic matter and nutrients occurred most rapidly in lowerelevation sites on the young flows, but the largest accumulations occurred at higher elevations on old flows. The range of sites sampled represents a complete and largely independent matrix of major factors governing ecosystem structure and function. ?? 1992 Springer-Verlag.

Vitousek, P. M.; Aplet, G.; Turner, D.; Lockwood, J. J.

1992-01-01

281

Stoichiometric patterns in foliar nutrient resorption across multiple scales  

USGS Publications Warehouse

*Nutrient resorption is a fundamental process through which plants withdraw nutrients from leaves before abscission. Nutrient resorption patterns have the potential to reflect gradients in plant nutrient limitation and to affect a suite of terrestrial ecosystem functions. *Here, we used a stoichiometric approach to assess patterns in foliar resorption at a variety of scales, specifically exploring how N : P resorption ratios relate to presumed variation in N and/or P limitation and possible relationships between N : P resorption ratios and soil nutrient availability. *N : P resorption ratios varied significantly at the global scale, increasing with latitude and decreasing with mean annual temperature and precipitation. In general, tropical sites (absolute latitudes < 23°26?) had N : P resorption ratios of < 1, and plants growing on highly weathered tropical soils maintained the lowest N : P resorption ratios. Resorption ratios also varied with forest age along an Amazonian forest regeneration chronosequence and among species in a diverse Costa Rican rain forest. *These results suggest that variations in N : P resorption stoichiometry offer insight into nutrient cycling and limitation at a variety of spatial scales, complementing other metrics of plant nutrient biogeochemistry. The extent to which the stoichiometric flexibility of resorption will help regulate terrestrial responses to global change merits further investigation.

Reed, Sasha C.; Townsend, Alan R.; Davidson, Eric A.; Cleveland, Cory C.

2012-01-01

282

Nutrient Acquisition and Metabolism by Campylobacter jejuni  

PubMed Central

The gastrointestinal pathogen Campylobacter jejuni is able to colonize numerous different hosts and compete against the gut microbiota. To do this, it must be able to efficiently acquire sufficient nutrients from its environment to support its survival and rapid growth in the intestine. However, despite almost 50?years of research, many aspects as to how C. jejuni accomplishes this feat remain poorly understood. C. jejuni lacks many of the common metabolic pathways necessary for the use of glucose, galactose, or other carbohydrates upon which most other microbes thrive. It does however make efficient use of citric acid cycle intermediates and various amino acids. C. jejuni readily uses the amino acids aspartate, glutamate, serine, and proline, with certain strains also possessing additional pathways allowing for the use of glutamine and asparagine. More recent work has revealed that some C. jejuni strains can metabolize the sugar l-fucose. This finding has upset years of dogma that C. jejuni is an asaccharolytic organism. C. jejuni also possesses diverse mechanisms for the acquisition of various transition metals that are required for metabolic activities. In particular, iron acquisition is critical for the formation of iron–sulfur complexes. C. jejuni is also unique in possessing both molybdate and tungsten cofactored proteins and thus has an unusual regulatory scheme for these metals. Together these various metabolic and acquisition pathways help C. jejuni to compete and thrive in wide variety of hosts and environments.

Stahl, Martin; Butcher, James; Stintzi, Alain

2012-01-01

283

Nutrient reserve dynamics of breeding canvasbacks  

USGS Publications Warehouse

We compared nutrients in reproductive and nonreproductive tissues of breeding Canvasbacks (Aythya valisineria) to assess the relative importance of endogenous reserves and exogenous foods. Fat reserves of females increased during rapid follicle growth and varied more widely in size during the early phase of this period. Females began laying with ca. 205 g of fat in reserve and lost 1.8 g of carcass fat for every 1 g of fat contained in their ovary and eggs. Females lost body mass (primarily fat) at a declining rate as incubation advanced. Protein reserves increased directly with dry oviduct mass during rapid follicle growth. This direct relationship was highly dependent upon data from 2 birds and likely biased by structural size. During laying, protein reserves did not vary with the combined mass of dry oviduct and dry egg protein. Between laying and incubation, mean protein reserves decreased by an amount equal to the protein found in 2.1 Canvasback eggs. Calcium reserves did not vary with the cumulative total of calcium deposited in eggs. Mean calcium reserve declined by the equivalent content of 1.2 eggs between laying and incubation. We believe that protein and calcium were stored in small amounts during laying, and that they were supplemented continually by exogenous sources. In contrast, fat was stored in large amounts and contributed significantly to egg production and body maintenance. Male Canvasbacks lost fat steadily--but not protein or calcium--as the breeding season progressed.

Barzen, J. A.; Serie, J. R.

1990-01-01

284

A Nutrient-Wide Association Study on Blood Pressure  

PubMed Central

Background A nutrient-wide approach may be useful comprehensively to test and validate associations between nutrients (derived from foods and supplements) and blood pressure (BP) in an unbiased manner. Methods and Results Data from 4,680 participants ages 40–59 in the cross-sectional International Study of Macro/Micro-nutrients and Blood Pressure (INTERMAP) were stratified randomly into training and testing sets. NHANES cross-sectional cohorts of 1999–2000 to 2005–2006 were used for external validation. We performed multiple linear regression analyses associating each of 82 nutrients and 3 urine electrolytes with systolic and diastolic BP in the INTERMAP training set. Significant findings were validated in the INTERMAP testing set and further in the NHANES cohorts (False Discovery Rate <5% in training, p<0.05 for internal and external validation). Among the validated nutrients, alcohol and urinary sodium-to-potassium ratio were directly associated with systolic BP, and dietary phosphorus, magnesium, iron, thiamin, folacin, and riboflavin were inversely associated with systolic BP. In addition, dietary folacin, and riboflavin were inversely associated with diastolic BP. The absolute effect sizes in the validation data (NHANES) ranged from 0.97 mmHg lower systolic BP (phosphorus) to 0.39 mmHg lower systolic BP (thiamin) per 1SD difference in nutrient variable. Inclusion of nutrient intake from supplements in addition to foods gave similar results for some nutrients, though it attenuated the associations of folacin, thiamin and riboflavin intake with BP. Conclusions We identified significant inverse associations between B vitamins and BP, relationships hitherto poorly investigated. Our analyses represent a systematic unbiased approach to the evaluation and validation of nutrient-BP associations.

Tzoulaki, Ioanna; Patel, Chirag J.; Okamura, Tomonori; Chan, Queenie; Brown, Ian J.; Miura, Katsuyuki; Ueshima, Hirotsugu; Zhao, Liancheng; Van Horn, Linda; Daviglus, Martha; Stamler, Jeremiah; Butte, Atul J.; Ioannidis, John P.A.; Elliott, Paul

2014-01-01

285

Hydroponic Crop Production using Recycled Nutrients from Inedible Crop Residues  

NASA Technical Reports Server (NTRS)

The coupling of plant growth and waste recycling systems is an important step toward the development of bioregenerative life support systems. This research examined the effectiveness of two alternative methods for recycling nutrients from the inedible fraction (residue) of candidate crops in a bioregenerative system as follows: (1) extraction in water, or leaching, and (2) combustion at 550 C, with subsequent reconstitution of the ash in acid. The effectiveness of the different methods was evaluated by (1) comparing the percent recovery of nutrients, and (2) measuring short- and long-term plant growth in hydroponic solutions, based on recycled nutrients.

Garland, Jay L.; Mackowiak, Cheryl L.; Sager, John C.

1993-01-01

286

Search the USDA National Nutrient Database for Standard Reference  

NSDL National Science Digital Library

The USDA Agricultural Research Service Nutrient Data Laboratory presents the National Nutrient Database, which has an easy-to-search interface that quickly retrieves nutritional data for every food item that contains a specific keyword. For instance, searching for "soybean" calls up a long list of food items for which soybean is an ingredient: various margarines, salad dressings, and oils; raw soybeans; steamed soybeans; roasted soybeans; and so on. The complete nutrition report for each item can then be viewed after selecting a unit of measurement (e.g., per 100 grams). The database may also be search by single nutrients, such as iron or folic acid.

2002-01-01

287

Nutrient Cycling in the Great Ouse Estuary and its Impact on Nutrient Fluxes to The Wash, England  

NASA Astrophysics Data System (ADS)

A programme of surveys of the Great Ouse estuary (England) was conducted to investigate the cycling of nutrients during mixing and to quantify nutrient budgets for the estuary. The Great Ouse estuary is shallow, well mixed and relatively turbid, and the dominant source of fresh water to The Wash. Surveys were conducted once or twice a month between February 1992 and January 1994 at high tide to yield seasonal and interannual information. High levels of chlorophyll a(>100 ?g l -1), oxygen supersaturation (>120%) and non-conservative nutrient distributions during spring and summer periods of low freshwater flow strongly suggest that primary production in the low-salinity reaches of the estuary may significantly modify nutrient fluxes to The Wash, despite the relatively high turbidity. In support, calculated nutrient budgets indicate that biological removal in the river and estuary during the growing season results in depleted nutrient fluxes and higher N:Si and P:Si ratios which may affect primary production in coastal waters by contributing to the shift in species dominance from diatoms to flagellates and affecting the likelihood of bloom conditions occurring during the summer months. However, the influence of estuarine biological processes on riverine nutrient fluxes is interrupted by periods of high freshwater flow, more characteristic of the winter months, which result in high flushing rates. Under such conditions, nutrient distributions revert to a more conservatively mixed regime. This fundamental control exerted by freshwater flow generally limits the significance of estuarine processes on an annual basis, the exception being the inorganic removal of phosphate in the low-salinity reaches of the estuary which accounts for one-third of the annual input to the head of the salinity gradient. Given the character of this agriculturally impacted estuary, which permits the relatively straightforward identification and quantification of nutrient cycling processes, results from this study may have wider application.

Rendell, A. R.; Horrobin, T. M.; Jickells, T. D.; Edmunds, H. M.; Brown, J.; Malcolm, S. J.

1997-11-01

288

Physicochemical stability of total nutrient admixtures.  

PubMed

The effect of six independent factors on the stability of i.v. nutritional emulsions was studied. Forty-five i.v. nutritional admixtures were prepared, each containing the following: (1) amino acids (range, 2.5-7%), (2) hydrated glucose (range, 5-20%), (3) lipid emulsion (range, 2-5%), (4) monovalent cations (range, 0-150 meq/L), (5) divalent cations (range, 4-20 meq/L), and (6) trivalent cations (range, 0-10 mg of elemental iron/L). Stability assessments included particle-size analysis, pH determination, and visual inspection. Sizing and counting of fat particles was achieved by using light obscuration and dynamic light scatter methods. Light obscuration and visual assessments were performed at 0, 6, 12, 24, and 30 hours. Dynamic light scatter and pH determinations were performed at 0 and 30 hours. Multiple stepwise regression analysis revealed that trivalent cation concentration was the only variable that affected the stability of nutritional emulsions (p < 0.00001), accounting for approximately 60% of the potentially dangerous increases in fat particle sizes observed. In addition, a percentage of large fat particles (> 5 microns in diameter) greater than 0.4% was associated with unstable emulsions. However, this instability was visibly evident only 65% of the time. Changes in mean globule diameter, cream-layer thickness, and pH did not reveal instability in these emulsions. Emulsions in which > 0.4% of the initial fat concentration consists of particles of > 5 microns in diameter are likely to become unstable. Of the six factors studied, the trivalent cation in iron dextran was most disruptive to lipid-based parenteral nutrient admixtures. PMID:7606577

Driscoll, D F; Bhargava, H N; Li, L; Zaim, R H; Babayan, V K; Bistrian, B R

1995-03-15

289

Using Stressor-Response Relationships to Derive Numeric Nutrient Criteria.  

National Technical Information Service (NTIS)

This document supplements existing nutrient criteria guidance (USEPA 2000a, 2000b, 2001, and 2008) by providing detailed approaches for estimating and interpreting stressor-response relationships for developing numeric criteria to address nitrogen/phospho...

2010-01-01

290

Marsh Soil Responses to Nutrients: Belowground Structural and Organic Properties  

EPA Science Inventory

Coastal marsh responses to nutrient enrichment apparently depend upon soil matrix and whether the system is primarily biogenic or minerogenic. Deteriorating organic rich marshes (Jamaica Bay, NY) receiving wastewater effluent had lower belowground biomass, organic matter, and soi...

291

Marsh Soil Responses to Nutrients: Belowground Structural and Organic Properties.  

EPA Science Inventory

Coastal marsh responses to nutrient enrichment apparently depend upon soil matrix and whether the system is primarily biogenic or minerogenic. Deteriorating organic rich marshes (Jamaica Bay, NY) receiving wastewater effluent had lower belowground biomass, organic matter, and soi...

292

Impact of Prescribed Fire on Understory and Forest Floor Nutrients.  

National Technical Information Service (NTIS)

The impact of low-intensity prescribed fires on slash pine/saw-palmetto/gallberry understory and forest floor nutrients was estimated from measurements before and after burning. Highly significant correlations existed between weight loss of these fuel com...

W. A. Hough

1981-01-01

293

Nutrient enrichment of the subarctic Pacific Ocean pycnocline  

NASA Astrophysics Data System (ADS)

At the end of the global thermohaline circulation, the subarctic Pacific is the richest nutrient repository in the world oceans. Trends towards lower oxygen and higher nutrients in waters below the surface layer (the pycnocline) have been observed in recent decades. We assess these trends using data from four programs and suggest the enrichment of pycnocline nitrate (200 Gmol y-1) is essential in keeping supply to the surface ocean constant, despite increasing upper ocean stratification. A nitrate budget helps identify possible vertical processes that could account for nutrient redistribution. We hypothesize that warming and oxygen loss in the deeper pycnocline, arising from ice loss in the Okhotsk Sea, have initiated a largely vertical redistribution of nutrients due to compression of vertical migrator habitat and/or changes in dissolution of sinking particulates. Coupled climate-ecosystem models will need to incorporate these processes to more fully understand projected changes in the subarctic Pacific.

Whitney, Frank A.; Bograd, Steven J.; Ono, Tsuneo

2013-05-01

294

Ozone alters the concentrations of nutrients in bean tissue  

SciTech Connect

Studies were conducted to determine the impact of ozone on the nutrient concentrations in tissue from various organs of beans (Phaseolus vulgaris L. cv Bush Bluelake 290). The plants were exposed to episodic concentrations of ozone in open-top field exposure chambers from soon after emergence until pod maturity. At harvest the leaf, stem, root and pod tissue were separated and dried (at 70C) to a constant weight. Nutrient concentrations in the tissue were determined using an inductively coupled plasma atomic emission spectrometer. Ozone exposure decreased the foliar concentrations of only four of the twelve nutrients analyzed (Ca, Mg, Fe and Mn) and increased the concentrations of three nutrients (K,P and Mo) in the pods. There were no significant changes in the macro- or micronutrient levels in the stem or root tissue. The decreased concentrations in the foliage appear to be the result of reduced transport into the leaves rather than reduced uptake or leaching.

Tingey, D.T.; Rodecap, K.D.; Lee, E.H.; Moser, T.J.; Hogsett, W.E.

1986-01-01

295

Nutrient Regeneration from Phytoplankton Decomposing in Sea Water.  

National Technical Information Service (NTIS)

A laboratory model of the regeneration of the inorganic nutrient salts of phosphorus, nitrogen, and silicon from diatom cells decaying in the dark while subject to bacterial attack was studied. The system was analyzed for phosphate, dissolved and particul...

E. V. Grill F. A. Richards

1964-01-01

296

LAKE ERIE NUTRIENT CONTROL: EFFECTIVENESS REGARDING ASSESSMENT IN EASTERN BASIN  

EPA Science Inventory

A three-year synoptic monitoring program was conducted on 26 stations from 1973-75. Data generated included major nutrients, temperature structure and oxygen depletion as well as phytoplankton, zooplankton, and benthic macroinvertebrate dynamics....

297

Rhoades Lecture. Effect of infection on nutrient requirements.  

PubMed

All infections, no matter how mild, decrease nutrient intakes and increase nutrient losses even when subclinical. The losses include decreased intestinal absorption, direct loss of nutrients in the gut, internal diversion for metabolic responses to infection and increased basal metabolic rate when fever is present. In this way, infection influences not only protein and energy status but also that of most other nutrients. The clinical importance of these consequences of infection depends on the prior state of the individual, the nature and duration of the infection, and the diet of the individual during the infection, particularly dietary intake during the convalescent period and whether full recovery takes place before another infection occurs. In industrialized countries particular attention must be paid to the nutrition of hospitalized patients inasmuch as they are frequently debilitated by their primary disease, morbidity, and nutritional status. Morbidity and mortality are increased by nosocomial infections to which the poorly nourished individual is more susceptible. PMID:1766046

Scrimshaw, N S

1991-01-01

298

Nonpoint Source - Stream Nutrient Level Relationships: A Nationwide Study.  

National Technical Information Service (NTIS)

National Eutrophication Survey (NES) data for a nationwide collection of 928 non-point source watersheds were studied for relationships between macro-drainage area characteristics (particularly land use) and nutrient levels in streams. Both the total and ...

J. M. Omernik

1977-01-01

299

Molecular Targets For Nutrients In Prostate Cancer Prevention  

Cancer.gov

Nutritional Science Research Group RFA CA-04-004: Molecular Targets For Nutrients In Prostate Cancer Prevention Principal Investigator and Organization Title of Project Bray, TammyOregon State University Diet, Endocrine-Immune Interactions & Prostate

300

Effects of Plant Species on Nutrient Cycling in Healthlands.  

National Technical Information Service (NTIS)

Contents: Decomposition and nutrient dynamics of litters and roots from heathlands; Species and site differences in the decomposition of litters and roots from wet heathlands. Carbon, nitrogen, and phosphorus dynamics in decomposing litters and roots in d...

M. van Vuuren

1992-01-01

301

Herbivores and nutrients control grassland plant diversity via light limitation  

USGS Publications Warehouse

Human alterations to nutrient cycles and herbivore communities are affecting global biodiversity dramatically. Ecological theory predicts these changes should be strongly counteractive: nutrient addition drives plant species loss through intensified competition for light, whereas herbivores prevent competitive exclusion by increasing ground-level light, particularly in productive systems. Here we use experimental data spanning a globally relevant range of conditions to test the hypothesis that herbaceous plant species losses caused by eutrophication may be offset by increased light availability due to herbivory. This experiment, replicated in 40 grasslands on 6 continents, demonstrates that nutrients and herbivores can serve as counteracting forces to control local plant diversity through light limitation, independent of site productivity, soil nitrogen, herbivore type and climate. Nutrient addition consistently reduced local diversity through light limitation, and herbivory rescued diversity at sites where it alleviated light limitation. Thus, species loss from anthropogenic eutrophication can be ameliorated in grasslands where herbivory increases ground-level light.

Borer, Elizabeth T.; Seabloom, Eric W.; Gruner, Daniel S.; Harpole, W. Stanley; Hillebrand, Helmut; Lind, Eric M.; Alder, Peter B.; Alberti, Juan; Anderson, T. Michael; Bakker, Jonathan D.; Biederman, Lori; Blumenthal, Dana; Brown, Cynthia S.; Brudvig, Lars A.; Buckley, Yvonne M.; Cadotte, Marc; Chu, Chengjin; Cleland, Elsa E.; Crawley, Michael J.; Daleo, Pedro; Damschen, Ellen I.; Davies, Kendi F.; DeCrappeo, Nicole M.; Du, Guozhen; Firn, Jennifer; Hautier, Yann; Heckman, Robert W.; Hector, Andy; HilleRisLambers, Janneke; Iribarne, Oscar; Klein, Julia A.; Knops, Johannes M. H.; La Pierre, Kimberly J.; Leakey, Andrew D. B.; Li, Wei; MacDougall, Andrew S.; McCulley, Rebecca L.; Melbourne, Brett A.; Mitchell, Charles E.; Moore, Joslin L.; Mortensen, Brent; O'Halloran, Lydia R.; Orrock, John L.; Pascual, Jesús; Prober, Suzanne M.; Pyke, David A.; Risch, Anita C.; Schuetz, Martin; Smith, Melinda D.; Stevens, Carly J.; Sullivan, Lauren L.; Williams, Ryan J.; Wragg, Peter D.; Wright, Justin P.; Yang, Louie H.

2014-01-01

302

Amino acid transceptors: gate keepers of nutrient exchange and regulators of nutrient signaling  

PubMed Central

Amino acid transporters at the surface of cells are in an ideal location to relay nutritional information, as well as nutrients themselves, to the cell interior. These transporters are able to modulate signaling downstream of intracellular amino acid receptors by regulating intracellular amino acid concentrations through processes of coupled transport. The concept of dual-function amino acid transporter/receptor (or “transceptor”) proteins is well established in primitive eukaryotes such as yeast, where detection of extracellular amino acid deficiency leads to upregulation of proteins involved in biosynthesis and transport of the deficient amino acid(s). The evolution of the “extracellular milieu” and nutrient-regulated endocrine controls in higher eukaryotes, alongside their frequent inability to synthesize all proteinaceous amino acids (and, hence, the requirement for indispensable amino acids in their diet), appears to have lessened the priority of extracellular amino acid sensing as a stimulus for metabolic signals. Nevertheless, recent studies of amino acid transporters in flies and mammalian cell lines have revealed perhaps unanticipated “echoes” of these transceptor functions, which are revealed by cellular stresses (notably starvation) or gene modification/silencing. APC-transporter superfamily members, including slimfast, path, and SNAT2 all appear capable of sensing and signaling amino acid availability to the target of rapamycin (TOR) pathway, possibly through PI 3-kinase-dependent mechanisms. We hypothesize (by extrapolation from knowledge of the yeast Ssy1 transceptor) that, at least for SNAT2, the transceptor discriminates between extracellular and intracellular amino acid stimuli when evoking a signal.

Hundal, Harinder S.; Taylor, Peter M.

2009-01-01

303

Wild and commercial mushrooms as source of nutrients and nutraceuticals  

Microsoft Academic Search

In order to promote the use of mushrooms as source of nutrients and nutraceuticals, several experiments were performed in wild and commercial species. The analysis of nutrients included determination of proteins, fats, ash, and carbohydrates, particularly sugars by HPLC-RI. The analysis of nutraceuticals included determination of fatty acids by GC-FID, and other phytochemicals such as tocopherols, by HPLC-fluorescence, and phenolics,

Lillian Barros; Telma Cruz; Paula Baptista; Letícia M. Estevinho; Isabel C. F. R. Ferreira

2008-01-01

304

Response of shallow aquatic ecosystems to different nutrient loading levels  

Microsoft Academic Search

Eutrophication of surface waters leads to a decline of water quality, which becomes manifest as an impoverishment of the aquatic community. Insight into the effects of eutrophication on the structure and functioning of these communities and knowlegde on underlying interactions is needed to quantify the required reduction of nutrient input.<\\/TT>To investigate the effects of nutrient loading on the receiving water,

R. Portielje

1994-01-01

305

Nutrient distributions, variability, and budgets in the Laptev Ssa system  

NASA Astrophysics Data System (ADS)

Studies of nutrient distribution and variability have a great ecological importance. Nutrients (silicate, phosphate and nitrate) are a mineral base for primary production in seawater. Nutrient budgets a indicate sea system metabolism. The aim of the report is to show the results of multiyear studies of nutrient distributions and it is budgeting in the Laptev Sea. New data were obtained in the recent Russian-German expeditions in frames of the bilateral project “Laptev Sea System”. Archive data of Arctic and Antarctic Research Institute were accumulated in the US-Russian Hydrochemical Atlas of the Arctic Ocean. Both of these data sets were used for our studies. The Laptev Sea is a region with highly variable physical processes, and high and variable rates of primary production and organic matter recycling. Extreme environmental changes (pulsing river run-off, coastal erosion, weather and ice conditions, seasonality of biological processes) cause extremely wide range of nutrient variability in space and time. The theory of structural zones and water mass formation is used to explain complicated nutrient distributions and variability. Transport and transformation of substances, including nutrients, in different structural zones occur in different ways. More then 70 % of the shallow Laptev Sea shelf is influenced by river water. Nutrient budgets in the river plume area were calculated for summer and winter according to the LOICZ recommendations. Budgeting results show that the system is acts as a net sink of dissolved inorganic phosphorus and nitrogen, excluding the bottom layer in winter. The system is also net nitrogen fixing in both summer and winter. It is necessary to notice, that the system is net autotrophic despite of the large river runoff.

Nitishinsky, M.; Pivovarov, S.

2003-04-01

306

Coupling Nutrient Uptake and Energy Flow in Headwater Streams  

Microsoft Academic Search

Nutrient cycling and energy flow in ecosystems are tightly linked through the metabolic processes of organisms. Greater uptake\\u000a of inorganic nutrients is expected to be associated with higher rates of metabolism [gross primary production (GPP) and respiration\\u000a (R)], due to assimilatory demand of both autotrophs and heterotrophs. However, relationships between uptake and metabolism\\u000a should vary with the relative contribution of

C. S. Fellows; H. M. Valett; C. N. Dahm; P. J. Mulholland; Steve Thomas

2006-01-01

307

Biochemical Markers and Nutrient Constraints Diagnosis in Citrus: A Perspective  

Microsoft Academic Search

Mineral deficiencies are well-established causal factor(s) for sub-optimum production in citrus. Identifying nutrient constraints based on morphological symptoms or in combination with leaf\\/soil analysis is often misleading, especially with reference to remediating the nutritional problems of a standing crop. The task becomes further confounded by other co-factors under the conditions favoring the occurrence of multi-nutrient deficiency. Important biochemical markers for

A. K. Srivastava; Shyam Singh

2006-01-01

308

Drug–Nutrient Interactions in Infancy and Childhood  

Microsoft Academic Search

\\u000a Objectives\\u000a \\u000a • Understand the impact of nutritional status on the growth and development of pediatric patients.\\u000a \\u000a \\u000a • Identify common interactions between drugs and nutrients and dietary supplements and nutrients, including vitamins.\\u000a \\u000a \\u000a • Discuss ways to manage medications to avoid interactions.

Laureen Murphy Kotzer; Maria R. Mascarenhas; Elizabeth Wallace

309

Water and Nutrient Transport in Nematode Feeding Sites  

Microsoft Academic Search

\\u000a Plant parasitic nematodes have developed complex strategies to obtain nutrients from their hosts. In many cases specialised\\u000a feeding cells are induced which establish a strong sink for water and nutrients. This chapter describes the different structural,\\u000a physiological and molecular mechanisms by which host plants were found to supply water and solutes over long and short distances.\\u000a A number of specific

Florian M. W. Grundler; Julia Hofmann

310

Selection of Optimal Auxiliary Soil Nutrient Variables for Cokriging Interpolation  

PubMed Central

In order to explore the selection of the best auxiliary variables (BAVs) when using the Cokriging method for soil attribute interpolation, this paper investigated the selection of BAVs from terrain parameters, soil trace elements, and soil nutrient attributes when applying Cokriging interpolation to soil nutrients (organic matter, total N, available P, and available K). In total, 670 soil samples were collected in Fuyang, and the nutrient and trace element attributes of the soil samples were determined. Based on the spatial autocorrelation of soil attributes, the Digital Elevation Model (DEM) data for Fuyang was combined to explore the coordinate relationship among terrain parameters, trace elements, and soil nutrient attributes. Variables with a high correlation to soil nutrient attributes were selected as BAVs for Cokriging interpolation of soil nutrients, and variables with poor correlation were selected as poor auxiliary variables (PAVs). The results of Cokriging interpolations using BAVs and PAVs were then compared. The results indicated that Cokriging interpolation with BAVs yielded more accurate results than Cokriging interpolation with PAVs (the mean absolute error of BAV interpolation results for organic matter, total N, available P, and available K were 0.020, 0.002, 7.616, and 12.4702, respectively, and the mean absolute error of PAV interpolation results were 0.052, 0.037, 15.619, and 0.037, respectively). The results indicated that Cokriging interpolation with BAVs can significantly improve the accuracy of Cokriging interpolation for soil nutrient attributes. This study provides meaningful guidance and reference for the selection of auxiliary parameters for the application of Cokriging interpolation to soil nutrient attributes.

Song, Genxin; Zhang, Jing; Wang, Ke

2014-01-01

311

Interactive Effects of Nutrient and Mechanical Stresses on Plant Morphology  

PubMed Central

Background and Aims Plant species frequently encounter multiple stresses under natural conditions, and the way they cope with these stresses is a major determinant of their ecological breadth. The way mechanical (e.g. wind, current) and resource stresses act simultaneously on plant morphological traits has been poorly addressed, even if both stresses often interact. This paper aims to assess whether hydraulic stress affects plant morphology in the same way at different nutrient levels. Methods An examination was made of morphological variations of an aquatic plant species growing under four hydraulic stress (flow velocity) gradients located in four habitats distributed along a nutrient gradient. Morphological traits covering plant size, dry mass allocation, organ water content and foliage architecture were measured. Key Results Significant interactive effects of flow velocity and nutrient level were observed for all morphological traits. In particular, increased flow velocity resulted in size reductions under low nutrient conditions, suggesting an adaptive response to flow stress (escape strategy). On the other hand, moderate increases in flow velocity resulted in increased size under high nutrient conditions, possibly related to an inevitable growth response to a higher nutrient supply induced by water renewal at the plant surface. For some traits (e.g. dry mass allocation), a consistent sense of variation as a result of increasing flow velocity was observed, but the amount of variation was either reduced or amplified under nutrient-rich compared with nutrient-poor conditions, depending on the traits considered. Conclusions These results suggest that, for a given species, a stress factor may result, in contrasting patterns and hence strategies, depending on a second stress factor. Such results emphasize the relevance of studies on plant responses to multiple stresses for understanding the actual ecological breadth of species.

Puijalon, Sara; Lena, Jean-Paul; Bornette, Gudrun

2007-01-01

312

Upper Mississippi Basin Loading Database (Sediment and Nutrients): Update  

NSDL National Science Digital Library

The Upper Midwest Environmental Sciences Center (UMESC) provides this updated database on sediments and nutrients of the Upper Mississippi River Basin. Included in the database are maps (Shape) showing the locations of monitoring stations; figures displaying rates of Nitrogen/ Phosphorus loadings and yields; and sediment and nutrient data by sub-area (ascii, .xls, Lotus). In addition, background information is provided on the monitoring sites.

313

Ecological classification of Nigerian mangroves using soil nutrient gradient analysis  

Microsoft Academic Search

Direct gradient analysis was used to relate the structure of mangrove communities to soil nutrient gradients. The predominant cations in the alluvial soils were magnesium and calcium, the values ranging from 8.6±0.9 to 24.6±2.0?me per 100?g. Organic carbon was high in the soils, ranging from 3.5% to 10.4%. All soil nutrients varied seasonally, in response to wet and dry periods

Imoh E. Ukpong

2000-01-01

314

Nutrient mobility in variable- and permanent-charge soils  

Microsoft Academic Search

Variable-charge (v-c) and permanent-charge (p-c) soils differ fundamentally with regard to many nutrient-cycling processes. Variable-charge soils are more common in the tropics than in temperature zones because their formation requires desilication, which proceeds fastest in warm, moist climates. The dynamics of nutrient mobility tend to be more complex in v-c than in p-c soils. For example, theory predicts that, as

Phillip Sollins; G. PHILIP ROBERTSON; Goro Uehara

1988-01-01

315

Nutrient Regulation of Insulin Secretion and ?-Cell Functional Integrity  

Microsoft Academic Search

\\u000a Pancreatic ?-cells are often referred to as “fuel sensors” as they continually monitor and respond to dietary nutrients, under\\u000a the modulation of additional neurohormonal signals, in order to secrete insulin to best meet the needs of the organism. ?-cell\\u000a nutrient sensing requires metabolic activation, resulting in production of stimulus-secretion coupling signals that promote\\u000a insulin biosynthesis and release. The primary stimulus

Philip Newsholme; Celine Gaudel; Neville H. McClenaghan

316

Selection of optimal auxiliary soil nutrient variables for cokriging interpolation.  

PubMed

In order to explore the selection of the best auxiliary variables (BAVs) when using the Cokriging method for soil attribute interpolation, this paper investigated the selection of BAVs from terrain parameters, soil trace elements, and soil nutrient attributes when applying Cokriging interpolation to soil nutrients (organic matter, total N, available P, and available K). In total, 670 soil samples were collected in Fuyang, and the nutrient and trace element attributes of the soil samples were determined. Based on the spatial autocorrelation of soil attributes, the Digital Elevation Model (DEM) data for Fuyang was combined to explore the coordinate relationship among terrain parameters, trace elements, and soil nutrient attributes. Variables with a high correlation to soil nutrient attributes were selected as BAVs for Cokriging interpolation of soil nutrients, and variables with poor correlation were selected as poor auxiliary variables (PAVs). The results of Cokriging interpolations using BAVs and PAVs were then compared. The results indicated that Cokriging interpolation with BAVs yielded more accurate results than Cokriging interpolation with PAVs (the mean absolute error of BAV interpolation results for organic matter, total N, available P, and available K were 0.020, 0.002, 7.616, and 12.4702, respectively, and the mean absolute error of PAV interpolation results were 0.052, 0.037, 15.619, and 0.037, respectively). The results indicated that Cokriging interpolation with BAVs can significantly improve the accuracy of Cokriging interpolation for soil nutrient attributes. This study provides meaningful guidance and reference for the selection of auxiliary parameters for the application of Cokriging interpolation to soil nutrient attributes. PMID:24927129

Song, Genxin; Zhang, Jing; Wang, Ke

2014-01-01

317

RESPONSE OF WHEAT TO FOLIAR APPLICATION OF NUTRIENTS  

Microsoft Academic Search

Foliar application can guarantee the availability of nutrients to crops for obtaining higher yield. To study the response of wheat to foliar application of nutrients, an experiment was conducted at Agricultural Research Farm of NWFP Agricultural University Peshawar during winter 2005-06. The treatments consist of control (water spray), spray at tillering (single spray) and\\/or spray at jointing (two sprays) and\\/or

Muhammad Arif; Muhammad Aslam Chohan; Sajid Ali; Rozina Gul; Sajjad Khan

2006-01-01

318

Flow rate of nutrient preparations through nasogastric tubes.  

PubMed Central

Experiments have been carried out in vitro to determine the relationships between the internal diameter of fine-bore nasogastric tubes, the viscosity of nutrient solutions, and the flow rate that can be achieved in the enteral feeding of surgical patients. It was found that such tubes are capable of delivering 3-5 l of nutrient solution in 24 h without a pump. The findings are discussed in relation to the supply of nitrogen and energy to the patient.

Skidmore, F. D.

1980-01-01

319

Springtime Nutrient and Phytoplankton Dynamics on Georges Bank  

Microsoft Academic Search

The dynamics of phytoplankton and nutrients before, during and after the winter-spring bloom on Georges Bank were studied on 6 monthly survey cruises from January to June 1999. We measured hydrography, phytoplankton cell densities, chlorophyll a, dissolved inorganic nutrients (NO3 + NO2, NH4, Si(OH)(4), PO4), dissolved organic nitrogen (DON) and phosphorus (DOP), particulate organic carbon (POC) and nitrogen (PON) and

David Townsend; M. Thomas

2002-01-01

320

Nutrient Transport into the White Sea with River Runoff  

Microsoft Academic Search

Averaged data from long-term observations of concentrations of mineral-nutrient fractions along with fragmentary data and indirect estimates of organic-component concentrations in the tributaries of the sea (the Niva, the Onega, the Northern Dvina, the Mezen, and the Kem rivers) are analyzed. Monthly variations in the concentrations of the major nutrients in the river water flowing into the sea are characterized,

A. V. Leonov; O. V. Chicherina

2004-01-01

321

Inventory of nutrient compounds in the Yellow Sea  

Microsoft Academic Search

Nutrient species were analyzed from samples collected in the Yellow Sea in May 1998, including NO3?, NO2?, NH4+, PO43?, SiO32?, dissolved organic nitrogen (DON), particulate nitrogen, dissolved organic phosphorus (DOP), particulate phosphorus, etc. The exchange fluxes of nutrients across the sediment\\/water interface were determined by incubation of sediment on board the ship. The concentrations of N, P and Si compounds

S. M Liu; J Zhang; S. Z Chen; H. T Chen; G. H Hong; H Wei; Q. M Wu

2003-01-01

322

Nutrients in mode waters of the northeast Atlantic  

NASA Astrophysics Data System (ADS)

Programme Océan Multidisciplinaire Méso Echelle (POMME) seasonal surveys in the northeast Atlantic (39°N-44.5°N; 16.5°W-20.3°W) in 2001 are used to investigate the subduction of nutrients in the subsurface mode waters. Isopycnal subsurface distributions are used to estimate inorganic nutrients at the time of late winter restratification. These nutrient concentrations were close to winter near-surface concentrations, indicating a moderate consumption of nitrate (0.2-0.3 ?M kg-1) and dissolved inorganic carbon (2-3 ?M kg-1) in the surface layer before the effective subduction. Spring survey nutrient concentrations on isopycnal surfaces are lower north of 41.7°N indicating younger waters than further south. The seasonal increase of subsurface nutrients from spring to late summer diminishes from the shallower isopycnals to the deeper ones of the mode waters. It is also larger north of 41.7°N than south of it with values as large as 2 ?M kg-1 for nitrate and 10 ?M kg-1 for inorganic carbon. This evolution is mostly attributed to remineralization processes, both from falling particles (at least 15%) and from preformed dissolved organic matter (at most 30%). Ratios of nutrient changes to oxygen changes are often larger than Redfield ratios for nitrate (N:apparent oxygen utilization (AOU) at least 1:7) and phosphate (P:AOU at least 1:150) consistent with favored remineralization of P and N over C, both for dissolved and particulate organic pools.

Reverdin, G.; LéVy, M.; Raimbault, P.; LefèVre, D.

2009-10-01

323

Status of selected nutrients in obese dogs undergoing caloric restriction  

PubMed Central

Background The purpose of this study was to test the hypothesis that dog plasma concentrations of selected nutrients decrease after undergoing caloric restriction for weight loss. Thirty-one overweight dogs that had successfully lost at least 15% of initial body weight were included in the study. Nutrients that had been previously identified to be at potential risk of deficiency during caloric restriction were measured in plasma (choline, amino acids) and urine (selenium) at the initiation and completion of a standardized weight loss regimen in dogs. Results Dogs remained healthy throughout the study, and no signs attributable to nutrient deficiency were noted. Percentage weight loss was 28.3% (16.0-40.1%) starting body weight, over a period of 250 days (91–674 days). Median energy intake during the weight loss period was 62 (44 to 74) Kcal/kg0.75 target weight per day. Choline (P?=?0.046) and threonine (P?=?0.02) decreased after weight loss. Glycine (P?=?0.041), and urinary selenium:creatinine ratio (P?=?0.006) both increased after weight loss. There were no other significant differences in plasma nutrient concentrations. Conclusions Since concentrations of most measured nutrients did not change significantly, the data are not consistent with widespread nutrient deficiency in dogs undergoing caloric restriction using a diet formulated for weight loss. However, the significance of the decrease in plasma choline concentration requires further assessment.

2013-01-01

324

Review of nutrient actions on age-related macular degeneration.  

PubMed

The actions of nutrients and related compounds on age-related macular degeneration (AMD) are explained in this review. The findings from 80 studies published since 2003 on the association between diet and supplements in AMD were reviewed. Antioxidants and other nutrients with an effect on AMD susceptibility include carotenoids (lutein and zeaxanthin, ?-carotene), vitamins (vitamin A, E, C, D, B), mineral supplements (zinc, copper, selenium), dietary fatty acids [monounsaturated fatty acids, polyunsaturated fatty acids (PUFA both omega-3 PUFA and omega-6 PUFA), saturated fatty acids and cholesterol], and dietary carbohydrates. The literature revealed that many of these antioxidants and nutrients exert a protective role by functioning synergistically. Specifically, the use of dietary supplements with targeted actions can provide minimal benefits on the onset or progression of AMD; however, this does not appear to be particularly beneficial in healthy people. Furthermore, some supplements or nutrients have demonstrated discordant effects on AMD in some studies. Since intake of dietary supplements, as well as exposure to damaging environmental factors, is largely dependent on population habits (including dietary practices) and geographical localization, an overall healthy diet appears to be the best strategy in reducing the risk of developing AMD. As of now, the precise mechanism of action of certain nutrients in AMD prevention remains unclear. Thus, future studies are required to examine the effects that nutrients have on AMD and to determine which factors are most strongly correlated with reducing the risk of AMD or preventing its progression. PMID:24461310

Zampatti, Stefania; Ricci, Federico; Cusumano, Andrea; Marsella, Luigi Tonino; Novelli, Giuseppe; Giardina, Emiliano

2014-02-01

325

Fish extinctions alter nutrient recycling in tropical freshwaters  

PubMed Central

There is increasing evidence that species extinctions jeopardize the functioning of ecosystems. Overfishing and other human influences are reducing the diversity and abundance of fish worldwide, but the ecosystem-level consequences of these changes have not been assessed quantitatively. Recycling of nutrients is one important ecosystem process that is directly influenced by fish. Fish species vary widely in the rates at which they excrete nitrogen and phosphorus; thus, altering fish communities could affect nutrient recycling. Here, we use extensive field data on nutrient recycling rates and population sizes of fish species in a Neotropical river and Lake Tanganyika, Africa, to evaluate the effects of simulated extinctions on nutrient recycling. In both of these species-rich ecosystems, recycling was dominated by relatively few species, but contributions of individual species differed between nitrogen and phosphorus. Alternative extinction scenarios produced widely divergent patterns. Loss of the species targeted by fishermen led to faster declines in nutrient recycling than extinctions in order of rarity, body size, or trophic position. However, when surviving species were allowed to increase after extinctions, these compensatory responses had strong moderating effects even after losing many species. Our results underscore the complexity of predicting the consequences of extinctions from species-rich animal communities. Nevertheless, the importance of exploited species in nutrient recycling suggests that overfishing could have particularly detrimental effects on ecosystem functioning.

McIntyre, Peter B.; Jones, Laura E.; Flecker, Alexander S.; Vanni, Michael J.

2007-01-01

326

Putting the nutrient-rich foods index into practice.  

PubMed

With approximately 2 out of 3 Americans currently overweight or obese, many continue to come up short on recommendations for certain nutrients such as calcium, magnesium, potassium, vitamin A, vitamin C, vitamin E, and fiber in their diet. Numerous attempts have been made to provide consumers with nutrient-profiling tools, such as manufacturer-specific symbols, to improve dietary selections, but many of the tools have focused on assisting consumers in making single food selections and do not provide guidance about planning total diets. In response to the 2005 Dietary Guidelines Advisory Committee's recommendation for research to define nutrient density, the Nutrient Rich Foods Coalition (NRFC) embarked on the development of a scientifically valid definition of nutrient density and consumer-driven educational tools to communicate the concept of nutrient-rich foods (NRF) to consumers. The science-based, consumer-driven NRF approach to eating may help Americans make multiple small changes in their diet that ultimately lead to better diet quality and significant improvements in public health. PMID:20368383

Mobley, Amy R; Kraemer, Dan; Nicholls, Jill

2009-08-01

327

Characterization of Pseudomonas putida Genes Responsive to Nutrient Limitation  

SciTech Connect

The low bioavailability of nutrients and oxygen in the soil environment has hampered successful expression of biodegradation/biocontrol genes that are driven by promoters highly active during routine laboratory conditions of high nutrient- and oxygen-availability. Hence, in the present study, expression of the gus-tagged genes in 12 Tn5-gus mutants of the soil microbe Pseudomonas putida PNL-MK25 was examined under various conditions chosen to mimic the soil environment: low carbon, phosphate, nitrate, or oxygen, and in the rhizosphere. Based on their expression profiles, three nutrient-responsive mutant (NRM) strains, NRM5, NRM7, and NRM17, were selected for identification of the tagged genes. In the mutant strain NRM5, expression of the glutamate dehydrogenase (gdhA) gene was increased between 4.9- to 26.4-fold under various low nutrient conditions. In NRM7, expression of the novel NADPH:quinone oxidoreductase-like (nql) gene was consistently amongst the highest and was synergistically upregulated by low nutrient and anoxic conditions. The cyoD gene in NRM17, which encodes the fourth subunit of the cytochrome o ubiquinol oxidase complex, had decreased expression in low nutrient conditions but its absolute expression levels was still amongst the highest. Additionally, it was independent of oxygen availability, in contrast to that in E. coli.

Syn, Chris K.; Magnuson, Jon K.; Kingsley, Mark T.; Swarup, Sanjay

2004-06-01

328

Primary Productivity Regime and Nutrient Removal in the Danube Estuary  

NASA Astrophysics Data System (ADS)

The primary productivity regime, as well as the distribution of dissolved inorganic nutrients and particulate organic matter in the Danube estuary, were investigated during several cruises at different discharge regimes of the Danube River. The shallowness of the upper surface layer due to insignificant tidal mixing and strong stratification of the Danube estuary, as well as the high nutrient concentrations, are favourable for elevated primary production. The incident light levels at the bottom of the upper surface layer of the water column (0·5-3·0 m) were generally higher than 20% of the surface irradiance. Elevated chlorophyll (Chl) aconcentrations with maxima at mid salinities were found during each survey. Within the upper mixed layer estimated primary production of 0·2-4·4 g m -2day -1is very high compared with estuaries of other major world rivers. Mixing diagrams of dissolved inorganic nutrients reveal removal of significant quantities of nutrients during estuarine mixing. These observations were consistent with the distribution of particular organic matter, which was negatively correlated to the nutrient distribution during each survey. C:Chl aratios, as well as the elevated estimated production, indicate that biological transformation processes govern the nutrient distribution in this estuary.

Humborg, C.

1997-11-01

329

Bay of Bengal nutrient-rich benthic layer  

NASA Astrophysics Data System (ADS)

A nutrient- and carbon-rich, oxygen-poor benthic layer is observed in the lower 100 m of the central and western Bay of Bengal, at depths between 3400 to 4000 m. The observed ratios for the biogeochemical anomalies in the benthic layer water are similar to those observed for phytoplankton blooms in open oceans and hence suggest that the source of the high silica, phosphate, nitrate and carbon is likely to be due to decomposition of marine plankton deposited on the Ganges fan. While similar sediment types are expected to exist across a more extensive area of the Bay of Bengal, accumulation of nutrients only within a confined pool of bottom water is due to a greater degree of ventilation elsewhere. To the north of the nutrient-rich benthic pool, in shallower water, inflow of water from West Australian Basin minimizes anomalous benthic properties. To the south, in deeper water, ventilation by bottom water of the Central Indian Basin lifts the Bay of Bengal nutrient-rich benthic water off the sea floor. Thus the nutrient-rich benthic layer occupies zone between better ventilated regions. A counter-clockwise flow of bottom water is suggested for the Bay of Bengal, with nutrient-rich bottom water flowing westward south of Sri Lanka.

Gordon, Arnold L.; Giulivi, Claudia F.; Takahashi, Taro; Sutherland, Stewart; Morrison, John; Olson, Donald

330

Potato growth and yield using nutrient film technique (NFT).  

PubMed

Potato plants, cvs Denali and Norland, were grown in polyvinyl chloride (PVC) trays using a continuous flowing nutrient film technique (NFT) to study tuber yield for NASA's Controlled Ecological Life Support Systems (CELSS) program. Nutrient solution pH was controlled automatically using 0.39M (2.5% (v/v) nitric acid (HNO3), while water and nutrients were replenished manually each day and twice each week, respectively. Plants were spaced either one or two per tray, allotting 0.2 or 0.4 m2 per plant. All plants were harvested after 112 days. Denali plants yielded 2850 and 2800 g tuber fresh weight from the one- and two-plant trays, respectively, while Norland plants yielded 1800 and 2400 g tuber fresh weight from the one- and two-plant trays. Many tubers of both cultivars showed injury to the periderm tissue, possibly caused by salt accumulation from the nutrient solution on the surface. Total system water usage throughout the study for all the plants equaled 709 liters (L), or approximately 2 L m-2 d-1. Total system acid usage throughout the study (for nutrient solution pH control) equaled 6.60 L, or 18.4 ml m-2 d-1 (7.2 mmol m-2 d-1). The results demonstrate that continuous flowing nutrient film technique can be used for tuber production with acceptable yields for the CELSS program. PMID:11537254

Wheeler, R M; Mackowiak, C L; Sager, J C; Knott, W M; Hinkle, C R

1990-01-01

331

[Compare the growth of Enteromorpha prolifera under different nutrient conditions].  

PubMed

Enteromorpha prolifera (E. prolifera) tides have erupted frequently in the Yellow Sea and brought serious environmental problems to coastal sea since 2007. In order to research the influence of nutrients on E. prolifera growth, mesocosm experiments were carried out in the Yellow Sea in May 2012. There were 12 mesocosms, including 9 different experimental conditions. It shows that the uptake ability of nutrients and the growth of E. prolifera are strong. The growth rate of E. prolifera reaches 82% when the nutrient level is appropriate, while the rate could also keep around 10% even under low nutrient conditions. When phosphate level is appropriate, high dissolved inorganic nitrogen (DIN) concentration could promote the growth of E. prolifera. Sufficient and continuous nutrient supplement is the material basis for outbreak of E. prolifera green tide. Through analyzing the amount of nutrient uptake by E. prolifera, the production of organics by photosynthesis could be estimated, which has a strong linear relationship with the increased of wet weight of E. prolifera. PMID:24288982

Pang, Qiu-ting; Li, Feng; Liu, Xiang-qing; Wang, Jiang-tao

2013-09-01

332

Nutrient density of beverages in relation to climate impact  

PubMed Central

The food chain contributes to a substantial part of greenhouse gas (GHG) emissions and growing evidence points to the urgent need to reduce GHGs emissions worldwide. Among suggestions were proposals to alter food consumption patterns by replacing animal foods with more plant-based foods. However, the nutritional dimensions of changing consumption patterns to lower GHG emissions still remains relatively unexplored. This study is the first to estimate the composite nutrient density, expressed as percentage of Nordic Nutrition Recommendations (NNR) for 21 essential nutrients, in relation to cost in GHG emissions of the production from a life cycle perspective, expressed in grams of CO2-equivalents, using an index called the Nutrient Density to Climate Impact (NDCI) index. The NDCI index was calculated for milk, soft drink, orange juice, beer, wine, bottled carbonated water, soy drink, and oat drink. Due to low-nutrient density, the NDCI index was 0 for carbonated water, soft drink, and beer and below 0.1 for red wine and oat drink. The NDCI index was similar for orange juice (0.28) and soy drink (0.25). Due to a very high-nutrient density, the NDCI index for milk was substantially higher (0.54) than for the other beverages. Future discussion on how changes in food consumption patterns might help avert climate change need to take both GHG emission and nutrient density of foods and beverages into account.

Smedman, Annika; Lindmark-Mansson, Helena; Drewnowski, Adam; Edman, Anna-Karin Modin

2010-01-01

333

Potato growth and yield using nutrient film technique (NFT)  

NASA Technical Reports Server (NTRS)

Potato plants, cvs Denali and Norland, were grown in polyvinyl chloride (PVC) trays using a continuous flowing nutrient film technique (NFT) to study tuber yield for NASA's Controlled Ecological Life Support Systems (CELSS) program. Nutrient solution pH was controlled automatically using 0.39M (2.5% (v/v) nitric acid (HNO3), while water and nutrients were replenished manually each day and twice each week, respectively. Plants were spaced either one or two per tray, allotting 0.2 or 0.4 m2 per plant. All plants were harvested after 112 days. Denali plants yielded 2850 and 2800 g tuber fresh weight from the one- and two-plant trays, respectively, while Norland plants yielded 1800 and 2400 g tuber fresh weight from the one- and two-plant trays. Many tubers of both cultivars showed injury to the periderm tissue, possibly caused by salt accumulation from the nutrient solution on the surface. Total system water usage throughout the study for all the plants equaled 709 liters (L), or approximately 2 L m-2 d-1. Total system acid usage throughout the study (for nutrient solution pH control) equaled 6.60 L, or 18.4 ml m-2 d-1 (7.2 mmol m-2 d-1). The results demonstrate that continuous flowing nutrient film technique can be used for tuber production with acceptable yields for the CELSS program.

Wheeler, R. M.; Mackowiak, C. L.; Sager, J. C.; Knott, W. M.; Hinkle, C. R.

1990-01-01

334

Insights into digestion and absorption of major nutrients in humans  

NSDL National Science Digital Library

Nutrient digestion and absorption is necessary for the survival of living organisms and has evolved into the complex and specific task of the gastrointestinal (GI) system. While most people simply assume that their GI tract will work properly to use nutrients, provide energy, and release wastes, few non-scientists know the details about how various nutrients are digested and how the breakdown products traverse the cells lining the small intestine to reach the blood stream and to be used by the other cells of the body. There have been several recent discoveries of new transporters that likely contribute to the absorption of oligopeptides and fatty acids. In addition, details are being clarified about how transporters work and in what forms nutrients can be absorbed. The enzymes that digest basic carbohydrates, proteins, and fats have been identified in various segments of the GI tract, and details are becoming clearer about what types of bonds they hydrolyze. Usually, detailed information about the digestion of basic nutrients is presented and learned in biochemistry courses and detailed information about absorption via transepithelial transport of the breakdown products of digestion is studied in physiology courses. The goal of this Staying Current article is to combine the details of the biochemistry of digestion with the updated information about the physiology of nutrient absorption into one source for teachers of physiology. Insights are included about some of the diseases and conditions that can bring about malabsorption of food in the GI tract and their consequences.

Barbara E. Goodman (Sanford School of Medicine, University of South Dakota Basic Biomedical Sciences)

2010-06-01

335

Nutrient Requirements of Domestic Animals. Number 7. Nutrient Requirements of Mink and Foxes (Second Revised Edition, 1982).  

National Technical Information Service (NTIS)

This second revision includes recent data, particularly from the Scandinavian countries, needed for the formulation of diets for mink and foxes. Extensive tables, including nutrient and energy requirements, formulas and data needed to calculate compositio...

1982-01-01

336

Effects of nutrient and paper mill biosolids amendments on the growth and nutrient status of hardwood forests  

Microsoft Academic Search

Aboveground net primary productivity (ANPP) and soil and vegetation nutrient concentrations were measured in pole-sized northern hardwood and aspen forests to quantify the potential for various nutrient amendments to increase tree growth, as well as potential deleterious effects on vegetation. Four blocks were installed in each forest type containing the following treatments: control, N+Ca+Mg+K+P+S (complete), wood-fired boiler ash (ash), N+wood-fired

Drew C Feldkirchner; Chuankuan Wang; Stith T Gower; Eric L Kruger; Jim Ferris

2003-01-01

337

Impact of the Invasive Alien Plant Solidago Gigantea on Primary Productivity, Plant Nutrient Content and Soil Mineral Nutrient Concentrations  

Microsoft Academic Search

Invasion by alien plants can alter ecosystem processes and soil properties. In this study, we compared aboveground productivity, nutrient pools in standing biomass and topsoil (0–0.10 m) mineral nutrient concentrations between plots invaded by Early Goldenrod (Solidago gigantea) and adjacent, uninvaded, vegetation at five sites in Belgium. The five sites were characterised by a resident perennial herbaceous vegetation and spanned a wide

Sonia Vanderhoeven; Nicolas Dassonville; Lydie Chapuis-Lardy; Matthieu Hayez; Pierre Meerts

2006-01-01

338

Light, nutrients, and herbivore growth in oligotrophic streams  

SciTech Connect

The light : nutrient hypothesis posits that herbivore growth is increasingly constrained by low food quality as the ratio of light to nutrients increases in aquatic ecosystems. We tested predictions of this hypothesis by examining the effects of large seasonal cycles in light and nutrients on the mineral content of periphyton and the growth rate of a dominant herbivore (the snail Elimia clavaeformis) in two oligotrophic streams. Streambed irradiances in White Oak Creek and Walker Branch (eastern Tennessee, USA) varied dramatically on a seasonal basis due to leaf phenology in the surrounding deciduous forests and seasonal changes in sun angle. Concentrations of dissolved nutrients varied inversely with light, causing light : nitrate and light : phosphate to range almost 100-fold over the course of any individual year. Periphyton nitrogen and phosphorus concentrations were much lower than the concentrations of these elements in snails, and they bottomed out in early spring when streambed irradiances were highest. Snail growth, however, peaked in early spring when light:nutrient ratios were highest and periphyton nutrient concentrations were lowest, Growth was linearly related to primary production (accounting for up to 85% of growth variance in individual years), which in turn was driven by seasonal variation in light. Conceptual models of herbivore growth indicate that growth should initially increase as increasing light levels stimulate primary production, but then level off, and then decrease as the negative effects of decreasing algal nutrient content override the positive effects of increased food production. Our results showed no evidence of an inflection point where increasing ratios of light to nutrients negatively affected growth. Snail growth in these intensively grazed streams is probably unaffected by periphyton nutrient content because exploitative competition for food reduces growth rates to levels where the demand for nitrogen and phosphorus is small enough to be satisfied by even low levels of these nutrients in periphyton. Competition for limited food resources in habitats where herbivore densities are uncontrolled by predation or other mortality factors should strongly influence the potential for herbivores to be limited by mineral deficits in their food

Hill, Walter R [ORNL; Smith, John G [ORNL; Stewart, Arthur J [ORNL

2010-02-01

339

Hydromorphological control of nutrient cycling in complex river floodplain systems  

NASA Astrophysics Data System (ADS)

Riparian zones and floodplains are key components within river ecosystems controlling nutrient cycling by promoting transformation processes and thus, act as biogeochemical hot spots. The intensity of these processes depends on the exchange conditions (the connectivity) with the main channel and the morphological setting of the water bodies. At the landscape scale, three interrelated principles of hydromorphological dynamics can be formulated regarding the cycling and transfer of carbon and nutrients in large rivers ecosystems: a) The mode of carbon and nutrient delivery affects ecosystem functioning; b) Increasing residence time and contact area impact nutrient transformation; c) Floods and droughts are natural events that strongly influence pathways of carbon and nutrient cycling. These three principles of hydromorphological dynamics control the nutrient uptake and retention and are linked over different temporal and spatial scales. All three factors can be strongly affected by natural disturbances or anthropogenic impacts, through a change in either the water regime or the geomorphologic setting of the river valley. Any change in natural water regimes will affect the biogeochemistry of riparian zones and floodplains as well as their ability to cycle and mitigate nutrient fluxes originating from upstream and/or upslope. Especially these areas have been altered by river regulation and land use changes over the last 200 years leading to the deterioration of the functioning of these compartments within the riverine landscape. The resulting deficits have prompted rehabilitation and restoration measures aiming to increase the spatial heterogeneity, the complexity, of these ecosystems. Yet, a more integrated approach is needed considering the present status of nutrient dynamics and the effects of restoration measures at different scales. The present paper analyses the effects of river side-arm restoration on ecosystem functions within the side-arm and highlights potential effects on the main channel in a large river, the Danube River. During the growing season of 2006 and the end of the growing season 2007, a large-scale field survey was completed for two areas in the floodplain stretch of the Danube River one of which has recently undergone restoration via reconnection to the Danube River main channel. The sampling compared the sediment nutrient concentrations and potential denitrification and respiration rates. With changing surface water connection to the Danube River, the water bodies in the two compared floodplains experienced different patterns of microbial processing rates, particularly potential denitrification. We demonstrate that principles of hydromorphological dynamics control nutrient cycling in the water column and at the water sediment interface. These findings confirm the environmental control on these processes and their potential use as proxies to assess the consequences of hydrological changes by restoration measures on river ecosystem functioning.

Hein, T.; Bondar-Kunze, E.; Felkl, M.; Habersack, H.; Mair, M.; Pinay, G.; Tritthart, M.; Welti, N.

2009-04-01

340

Light, nutrients, and herbivore growth in oligotrophic streams.  

PubMed

The light : nutrient hypothesis posits that herbivore growth is increasingly constrained by low food quality as the ratio of light to nutrients increases in aquatic ecosystems. We tested predictions of this hypothesis by examining the effects of large seasonal cycles in light and nutrients on the mineral content of periphyton and the growth rate of a dominant herbivore (the snail Elimia clavaeformis) in two oligotrophic streams. Streambed irradiances in White Oak Creek and Walker Branch (eastern Tennessee, USA) varied dramatically on a seasonal basis due to leaf phenology in the surrounding deciduous forests and seasonal changes in sun angle. Concentrations of dissolved nutrients varied inversely with light, causing light : nitrate and light : phosphate to range almost 100-fold over the course of any individual year. Periphyton nitrogen and phosphorus concentrations were much lower than the concentrations of these elements in snails, and they bottomed out in early spring when streambed irradiances were highest. Snail growth, however, peaked in early spring when light:nutrient ratios were highest and periphyton nutrient concentrations were lowest, Growth was linearly related to primary production (accounting for up to 85% of growth variance in individual years), which in turn was driven by seasonal variation in light. Conceptual models of herbivore growth indicate that growth should initially increase as increasing light levels stimulate primary production, but then level off, and then decrease as the negative effects of decreasing algal nutrient content override the positive effects of increased food production. Our results showed no evidence of an inflection point where increasing ratios of light to nutrients negatively affected growth. Snail growth in these intensively grazed streams is probably unaffected by periphyton nutrient content because exploitative competition for food reduces growth rates to levels where the demand for nitrogen and phosphorus is small enough to be satisfied by even low levels of these nutrients in periphyton. Competition for limited food resources in habitats where herbivore densities are uncontrolled by predation or other mortality factors should strongly influence the potential for herbivores to be limited by mineral deficits in their food. PMID:20392016

Hill, Walter R; Smith, John G; Stewart, Arthur J

2010-02-01

341

Nutrient concentration, resorption and lifespan: leaf traits of Australian sclerophyll species  

Microsoft Academic Search

Summary 1. Most plants withdraw nutrients from leaves as they age, and redeploy them else- where in the plant. The proportion of nutrients resorbed and the residual nutrient concentration in senesced leaves are different but complementary indices of nutrient conservation via this process. A major spectrum of strategic variation runs from plant species with typically long leaf lifespan (LL), high

I. J. Wright; M. Westoby

2003-01-01

342

Intraspecific competition in Fucus serratus germlings: The interaction of light, nutrients and density  

Microsoft Academic Search

A factorial experiment investigated the effects of irradiance and nutrients on the growth and death of germlings of Fucus serratus (L.) cultured at different densities. Nutrient status, which consisted of nutrient enriched or normal filtered sea-water, was found to be the most important factor. Under high nutrient levels in culture plant growth was greatly stimulated, resulting in a more variable\\/unequal

Joel C Creed; T. A Norton

1997-01-01

343

Paradoxical nutritional deficiency in overweight and obesity: the importance of nutrient density  

Microsoft Academic Search

Overweight and obese patients may develop paradoxical nutritional deficiency from eating high-energy foods with a poor nutrient content. In such patients, this condition is probably under-recognised, and thus untreated. • The nutrient density of foods has recently been defined by a score — the naturally nutrient-rich (NNR) score — which assesses the contribution a food makes to the nutrient intake

Tania P Markovic; Sharon J Natoli

2009-01-01

344

Growth of Loblolly Pine and White Pine after Enrichment by Nutrient Loading  

Microsoft Academic Search

Low nutrient availability often constrains the growth of young trees following planting to fields or forests. Nutrient loading of young tree seedlings increases their growth in outplanting. Loblolly pine (Pinus taeda L.) and white pine (Pinus strobus L.) were grown for one year on nutrient-loading regimes that varied from 13 to 410 mg N L in sand culture. Other nutrients

Allen V. Barker

2010-01-01

345

Relationship of forest productivity to nutrient and carbon supply-a modeling analysis  

Microsoft Academic Search

Summary A simple model of photosynthetic and nutritional controls over foliar dynamics is analyzed to compare the magnitude of the growth response of forest stands to increased rates of photosynthesis and nutrient supply. According to the model, productivity achieved at canopy closure is sensitive to nutrient supply, except where nutrient availability exceeds the plants' uptake capacity. Plants growing under nutrient-lim-

ROSS E. McMURTRIE

346

Reducing future nutrient inputs to the Black Sea.  

PubMed

Rivers export increasing amounts of dissolved inorganic (DIN, DIP) and organic (DON, DOP) nitrogen and phosphorus to the Black Sea causing coastal eutrophication. The aim of this study is to explore future trends in river export of these nutrients to the sea through a sensitivity analysis. We used the Global NEWS (Nutrient Export from WaterSheds) model to this end. We calculated that between 2000 and 2050 nutrient inputs to the Black Sea may increase or decrease, depending on the assumed environmental management. We analyzed the effects of agricultural and sewage management on nutrient inputs to the sea in 2050 relative to two Millennium Ecosystem Assessment (MEA) scenarios, Global Orchestration (GO) and Adaptive Mosaic (AM). In these baselines, total N and P inputs to the Black Sea decrease between 2000 and 2050, but not for all rivers and nutrient forms. Our results indicate that it is possible to reduce nutrient inputs to the sea further between 2000 and 2050 in particular for dissolved inorganic N and P and for many river basins, but not for all. For scenarios assuming combined agricultural and sewage management dissolved inorganic N and P inputs to the Black Sea are reduced by up to two-thirds between 2000 and 2050 and dissolved organic N and P inputs by one-third. River export of DIN is mainly affected by agricultural management and that of DIP by sewage management. On the other hand, in scenarios assuming increased fertilizer use for, for instance bioenergy crops, nutrient inputs to the sea increase. An increase in DIP inputs by southern rivers seems difficult to avoid because of the increasing number of people connected to sewage systems. PMID:23906857

Strokal, Maryna Petrivna; Kroeze, Carolien; Kopilevych, Volodymyr Abramovych; Voytenko, Larysa Vladyslavivna

2014-01-01

347

Soil Nutrient Assessment for Urban Ecosystems in Hubei, China  

PubMed Central

Recent urban landscape vegetation surveys conducted in many cities in China identified numerous plant nutrient deficiencies, especially in newly developed cities. Soil nutrients and soil nutrient management in the cities of Hubei province have not received adequate attention to date. The aims of this study were to characterize the available nutrients of urban soils from nine cities in Hubei province, China, and to assess how soil nutrient status is related to land use type and topography. Soil nutrients were measured in 405 sites from 1,215 soil samples collected from four land use types (park, institutional [including government building grounds, municipal party grounds, university grounds, and garden city institutes], residential, and roadside verges) and three topographies (mountainous [142–425 m a.s.l], hilly [66–112 m a.s.l], and plain [26–30 m a.s.l]). Chemical analyses showed that urban soils in Hubei had high pH and lower soil organic matter, available nitrogen (N), available phosphorus (P), and available boron (B) concentrations than natural soils. Nutrient concentrations were significantly different among land use types, with the roadside and residential areas having greater concentrations of calcium (Ca), sulfur (S), copper (Cu), manganese (Mn), and zinc (Zn) that were not deficient against the recommended ranges. Topographic comparisons showed statistically significant effects for 8 of the 11 chemical variables (p < 0.05). Concentrations of N, Ca, Mg, S, Cu, and Mn in plain cities were greater than those in mountainous cities and show a negative correlation with city elevation. These results provide data on urban soils characteristics in land use types and topography, and deliver significant information for city planners and policy makers.

Li, Zhi-guo; Zhang, Guo-shi; Liu, Yi; Wan, Kai-yuan; Zhang, Run-hua; Chen, Fang

2013-01-01

348

A COMPARATIVE ANALYSIS OF NUTRIENT LOADING, NUTRIENT RETENTION AND NET ECOSYSTEM METABOLISM IN THREE TIDAL RIVER ESTUARIES DIFFERING PREDOMINATELY BY THEIR WATERSHED LAND USE TYPES.  

EPA Science Inventory

Abstract and oral presentation for the Estuarine Research Federation Conference. Estuarine retention of watershed nutrient loads, system-wide nutrient biogeochemical fluxes, and net ecosystem metabolism (NEM) were determined in three estuaries exhibiting differing magnitud...

349

The Relationship of Mineral Nutrients to Growth of 'Spartina alterniflora' in North Carolina: I. Nutrient Status of Plants and Soils in Natural Stands.  

National Technical Information Service (NTIS)

Multiple regression analysis was utilized to examine relationships between nutrient concentration in the plant tissue and/or nutrient status of the soil and differences in productivity of Spartina alterniflora, among marshes and between height zones withi...

S. W. Broome W. W. Woodhouse E. D. Seneca

1974-01-01

350

Transport of groundwater-borne nutrients from watersheds and their effects on coastal waters  

Microsoft Academic Search

Anthropogenic activities on coastal watersheds increase nutrient concentrations of groundwater. As groundwater travels downslope\\u000a it transports these nutrients toward the adjoining coastal water. The resulting nutrient loading rates can be significant\\u000a because nutrient concentrations in coastal groundwaters may be several orders of magnitude greater than those of receiving\\u000a coastal waters. Groundwater-borne nutrients are most subject to active biogeochemical transformations as

Ivan Valiela; Joseph Costa; Kenneth Foreman; John M. Teal; Brian Howes; David Aubrey

1999-01-01

351

Nutrient dynamics in Amazon shelf waters: results from AMASSEDS  

NASA Astrophysics Data System (ADS)

Four hydrographic cruises were conducted on the Amazon shelf as part of the AMASSEDS field program. During each cruise, approximately 55 stations were occupied and nutrients, as well as other hydrographic parameters, were measured. The results of this time series sampling program indicate that the nutrient concentrations in the riverine end-member (silicate = 144 ?mol kg -1, phosphate = 0.7 ?mol kg -1, nitrate = 16 ?mol kg -1, ammonium = 0.4 ?mol kg -1, and urea = 0.9 ?mol kg -1) remain relatively constant, despite a two-fold seasonal variation in river water discharge rate. Of the major nutrients (nitrate, phosphate, ammonium and silicate), nitrate shows the greatest seasonal change in riverine end-member concentration with a high value (23 ?mol kg -1) during the March cruise (rising river discharge) and a low value (12 ?mol kg -1) during the November cruise (falling river discharge). Nitrate is the dominant nutrient form of inorganic nitrogen throughout most of the river/ocean mixing zone, however, in the outershelf area, where nitrate has been depleted by biological production, this nutrient occurs at concentrations comparable to the other nitrogen species (ammonium, nitrite and urea), which are at levels < 1 ?mol kg -1. Nearshore, high turbidity inhibits phytoplankton production because of light limitation, whereas on the outershelf, nitrate appears to be limiting growth more than silicate or phosphate. Nutrient uptake was observed during all four cruises, however, nearly all of this production must be regenerated in shelf bottom waters, because very little of the biogenic materials are buried in the seabed (silicate burial <4% of flux to algal blooms; ˜10% burial of biologically available inorganic nitrogen reaching the river/ocean mixing zone; and <3% burial of phosphate flux to shelf environment). Clearly the Amazon shelf is not an efficient nutrient trap. Initial estimates of primary production on the Amazon shelf suggest that algal blooms are sustained by regeneration to a large extent (up to 83%, 69% and 59% for N, P and Si, respectively) as well as by riverine and upwelled sources. Nutrient budget calculations have been used to establish the dominant external source of nutrients to the algal blooms occurring on the outer shelf. Based on flux core measurements, diffusive nutrient fluxes from Amazon shelf sediments are very low relative to riverine supply rates (silicate flux out = 1.3% of riverine flux, the nitrate plus ammonium flux is essentially zero, and the phosphate seabed flux shows removal of ˜2% of the riverine flux). Inventories of naturally occurring 210Pb were used to estimate the onshore flow of subsurface water onto the Amazon shelf. The radiochemical data indicate that the flux of water onto the shelf may be as much as five to ten times greater than the annual flow of the Amazon River. The nutrient flux from this shoreward movement of ocean water (originating at a depth of 60-100 m water depth) accounts for about 80% of the externally supplied ammonium, 52% of the externally supplied phosphate, 38% of the externally supplied nitrate, and 17% of the externally supplied silicate reaching the outer shelf, with the remainder of the nutrient fluxes coming from the river. Therefore, the outershelf algal blooms are supported to a significant extent by the shoreward flux of nutrients from offshore, subsurface waters.

Demaster, David J.; Pope, Robert H.

1996-03-01

352

Critical source times for nutrient loss in agricultural catchment streams  

NASA Astrophysics Data System (ADS)

Identifying periods of the year when there is a high risk of incidental nutrient loss from farms via runoff to streams underpins current nutrient management legislation in Europe. This research explored high-temporal resolution nutrient transfer patterns relative to the time that manure and fertiliser are prohibited from being spread (the mandatory spreading 'closed' period) in five Irish agricultural catchments. Catchment nutrient losses during the 12 week closed periods in 2009-10, 2010-11 and 2011-12 were compared with losses during the remainder of the year, and with losses in the two week 'shoulder' periods immediately before and after the closed period. The closed period losses were assumed to be residual from soil nutrient stores and the 'shoulder' periods were considered to also include incidental losses. Nutrient loss was measured at sub-hourly frequency as total phosphorus (P) and total oxidised nitrogen (mostly nitrate-N) fluxes in streamflow. The streamflow fluxes showed that the proportion of the annual nitrate-N loss occurring during the closed periods (33-61%) was high compared with the remainder of the year. Six to ten times more nitrate-N loss occurred in the two weeks after, compared with the two weeks before, the closed period. These two week 'shoulder' period losses were, on average, less than or equal to 2.5 kg nitrate-N/ha and 9% of total annual nitrate-N loss in streamflow. On average, 40-53% of the annual P loss occurred during the closed periods but in a runoff-prone catchment in a year with a wet summer, the closed period was the less risky period. Similar to nitrate-N, two to twenty times more P loss occurred in the two weeks after, compared with the two weeks before, the closed period. These shoulder period losses were, on average, less than or equal to 0.027 kg/ha and 4.2% of total annual P loss in streamflow. The proportion of the shoulder period loss that could be attributed to recently spread nutrients was not known but can be informed by farm practice and nutrient flow pathways analysis. Losses after the closed period, especially P, could include a significant contribution from eroded soil, which would not be prevented by extending the spreading closed period. Policy proposals to extend the mandatory closed period should consider the long term potential for nutrient runoff and plant growth conditions during the 'shoulder' periods, infrastructure costs of further storage requirements, production costs of restricting critical farm operations during the shoulders and unintended environmental costs such as shifting farm activities towards periods when water bodies are more susceptible to eutrophication.

Melland, Alice; Shore, Mairead; Mellander, Per-Erik; McDonald, Noeleen; Shortle, Ger; Murphy, Paul; Jordan, Phil

2014-05-01

353

Nutrient Overland Flow and Nitrous Oxide Losses from Residential Landscapes  

NASA Astrophysics Data System (ADS)

Residential lawn maintenance practices (mowing, fertilizer, irrigation, reseeding, and aeration) result in aesthetically appealing landscapes, but is capable of causing nutrient losses via overland flow or gaseous losses to the atmosphere (e.g. nitrous oxide - N2O). The overall study objective was to determine the effect of lawn maintenance on nutrient losses from residential landscapes. The specific objectives were: modify a passive sampling system to determine nutrient loads due to overland flow from lawns; evaluate differences in overland flow frequency, volumes, and nutrient losses during rainfall events (? 25.4 mm); and compare N2O losses following rainfall events. Three distinct lawn schemes were studied: a high maintenance fescue (Festuca arundinacea) lawn (HMFL), a low maintenance fescue lawn (LMFL), and a mixed forested residential landscape (FRL). The modified passive sampling system allowed 100% recovery of overland flow and demonstrated that differences in maintenance influenced the overland flow frequency, volumes, and nutrient losses. The LMFL had the greatest overland flow volumes and nutrient unit area loads; although N and P concentrations in overland flow exceeded USEPA recommendations from all three lawns. Nutrient losses (g ha-1 yr-1) from all three residential landscapes were 1000 times less than fertilizer (kg ha-1 yr-1) and throughfall (kg ha-1 yr-1) inputs, partially due to the presence of well-structured soils (low bulk densities and high infiltration rates). Irrigation practices between the HMFL and LMFL explained the differences in overland flow volumes and nutrient loads, especially during the first half of the study when drought conditions existed at the study site (Cary, North Carolina). The lack of irrigation in the LMFL resulted in early dormancy and a minimal thatch layer and lower plant density, which caused higher volumes of overland flow. Trends in the N2O losses from the HMFL and LMFL were associated with timing of fertilizer applications, presence or absence of irrigation, and seasonal growth patterns of the fescue. For the RFL, the presence of a decomposing litter layer limited N2O production. Well-maintained residential lawns, receiving recommended fertilizer N applications and frequent irrigation, reduce nutrient losses via overland flow but may provide optimum conditions for greater N2O fluxes.

Osmond, D.; Spence, P.; Heitman, J.; Robarge, W. P.; Walker, J. T.; water quality, nitrogen emissions, residential landscapes

2011-12-01

354

Solution culture method for studying nutrient uptake and stress  

SciTech Connect

In order to study the uptake of two (or more) different mineral nutrients at very low concentrations, a solution culture system with new capabilities was developed. It allows tight control of nutrient concentrations of very low levels, accurate uptake rate measurements, and frequent non-destructive measurements of plant mass and dimensions. The hydroponic system includes (1) a water-deionizing system, (2) an automated mixing system that can provide up to 3000 liters/day of the base solution containing the non-varied nutrients; (3) seven separate reciprocating syringe pumps, each of which mixes base solution and concentrates of the two varied nutrients and supplies an entire set of plants for one nutritional treatment; (4) growth pots, consisting of 2-liter plastic beakers divided internally into three separate compartments, each provided with a separate nutrient inflow, drain, and aerator/mixer. This once-through (non-recirculating) flow system is constructed entirely of plastics and lesser amounts of other materials in order to minimize chemical contamination. Numerous other advantages are discussed. 3 references, 1 table.

Kay, L.E.; Gutschick, V.P.

1984-01-01

355

Nutrient depletion in Bacillus subtilis biofilms triggers matrix production  

NASA Astrophysics Data System (ADS)

Many types of bacteria form colonies that grow into physically robust and strongly adhesive aggregates known as biofilms. A distinguishing characteristic of bacterial biofilms is an extracellular polymeric substance (EPS) matrix that encases the cells and provides physical integrity to the colony. The EPS matrix consists of a large amount of polysaccharide, as well as protein filaments, DNA and degraded cellular materials. The genetic pathways that control the transformation of a colony into a biofilm have been widely studied, and yield a spatiotemporal heterogeneity in EPS production. Spatial gradients in metabolites parallel this heterogeneity in EPS, but nutrient concentration as an underlying physiological initiator of EPS production has not been explored. Here, we study the role of nutrient depletion in EPS production in Bacillus subtilis biofilms. By monitoring simultaneously biofilm size and matrix production, we find that EPS production increases at a critical colony thickness that depends on the initial amount of carbon sources in the medium. Through studies of individual cells in liquid culture we find that EPS production can be triggered at the single-cell level by reducing nutrient concentration. To connect the single-cell assays with conditions in the biofilm, we calculate carbon concentration with a model for the reaction and diffusion of nutrients in the biofilm. This model predicts the relationship between the initial concentration of carbon and the thickness of the colony at the point of internal nutrient deprivation.

Zhang, Wenbo; Seminara, Agnese; Suaris, Melanie; Brenner, Michael P.; Weitz, David A.; Angelini, Thomas E.

2014-01-01

356

[Nutrients in atmospheric wet deposition in the East China Sea].  

PubMed

92 rainwater samples were collected at Shengsi Archipelago from January 2008 to December 2009. The pH and the concentrations of nutrients (NH4(+), NO3(-) + NO2(-), PO4(3-), SiO3(2-)) were analyzed using spectrophotometry to understand the impacts of the atmospheric wet deposition on the ecosystem of the East China Sea. The results showed that the pH of 85% samples were less than 5.0, and had significant effect on the environment. There were significant differences among monthly average concentrations of nutrients and rainfall and seasonal average wet deposition of nutrients in investigation periods. The annual average wet deposition flux was 52.05 mmol x (m2 x a) (-1) for DIN, 0.08 mmol x (m2 x a) (-1) for PO4(3-), 2.05 mmol x (m2 x a) (-1) for SiO3(2-). The average molar ratios of NO3(-)/NH4(+) is 0.73, N: P ratio is 684: 1, indicating that nutrients composition in rainwater was different from seawater of the East China Sea Shelf (10-150). The wet deposition may change the nutrients structure, pH and lead to change the phytoplankton production in the surface seawater of the East China Sea, even lead to the red tide. PMID:22165245

Zhu, Yu-Mei; Liu, Su-Mei

2011-09-01

357

Sedimentary nutrient dynamics in a tropical estuarine mangrove ecosystem  

NASA Astrophysics Data System (ADS)

Mangrove sediments play a pivotal role in the nutrient biogeochemical processes by behaving as both source and sink for nutrients and other materials. Surface and core sediments were collected from various locations of the Pichavaram mangrove (India) and analyzed for grain size distribution, nutrients and stable N isotope (? 15N) signatures in order to understand the spatial and vertical distribution of nutrients and biogeochemical processes of the C, N, P and S in this ecosystem. Sand is the dominant fraction followed by silt and clay. Spatial distribution of nutrients is controlled by the external and internal loadings, whereas vertical distribution is largely driven by the in situ microbial activities. Interior mangrove sediments contain higher concentrations of organic carbon (OC) than the estuarine sediments reflecting high rates of organic matter retention. Finer fractions of sediment hold ˜60% OC due to high surface area. At some sampling points, moderately high ? 15N signatures were observed and this may be because of agricultural runoff and aquaculture effluents.

Krishna Prasad, M. Bala; Ramanathan, A. L.

2008-10-01

358

Parallel Exploitation of Diverse Host Nutrients Enhances Salmonella Virulence  

PubMed Central

Pathogen access to host nutrients in infected tissues is fundamental for pathogen growth and virulence, disease progression, and infection control. However, our understanding of this crucial process is still rather limited because of experimental and conceptual challenges. Here, we used proteomics, microbial genetics, competitive infections, and computational approaches to obtain a comprehensive overview of Salmonella nutrition and growth in a mouse typhoid fever model. The data revealed that Salmonella accessed an unexpectedly diverse set of at least 31 different host nutrients in infected tissues but the individual nutrients were available in only scarce amounts. Salmonella adapted to this situation by expressing versatile catabolic pathways to simultaneously exploit multiple host nutrients. A genome-scale computational model of Salmonella in vivo metabolism based on these data was fully consistent with independent large-scale experimental data on Salmonella enzyme quantities, and correctly predicted 92% of 738 reported experimental mutant virulence phenotypes, suggesting that our analysis provided a comprehensive overview of host nutrient supply, Salmonella metabolism, and Salmonella growth during infection. Comparison of metabolic networks of other pathogens suggested that complex host/pathogen nutritional interfaces are a common feature underlying many infectious diseases.

Steeb, Benjamin; Claudi, Beatrice; Burton, Neil A.; Tienz, Petra; Schmidt, Alexander; Farhan, Hesso; Maze, Alain; Bumann, Dirk

2013-01-01

359

Experimental Tests of Nutrient Limitation in Freshwater Picoplankton  

PubMed Central

On the basis of correlative studies, picoplankton in Calder Lake, New York, are apparently unaffected by seasonal fluxes in nutrient (N and P) levels. In this small eutrophic lake, picoplankton (<2.0- to 0.2-?m size) and nanoplankton (<20 to >2 ?m) predominate. Microplankton (>20 ?m) are typically least important. Experiments were conducted in situ to test whether N, P or N/P ratios affect the predominance of these smaller organisms. Manipulations were run in 4-liter microcosms during June, July, and August 1988, corresponding to periods of increasing stratification and nutrient depletion. Following nutrient additions, phytoplankton were harvested and fractionated into three size classes. Microplankton and nanoplankton were significantly stimulated by both N (2.5 to 50 ?M) and P (1 to 20 ?M) additions. The severity of nutrient limitation was greatest during July. Picoplankton responded less strongly to N additions and were never P limited. These field data support laboratory studies which indicate that bacterium-sized phytoplankton use nutrients more efficiently and are superior competitors within mixed communities.

Wehr, John D.

1989-01-01

360

Competition for one nutrient with internal storage and toxin mortality.  

PubMed

This study presents a mathematical model of two species competing in a chemostat for one resource that is stored internally, and who also compete through allelopathy. Each species produces a toxin to that increases mortality rate of its competitor. The two species system and its single species subsystem follow mass conservation constraints characteristic of chemostat models. Persistence of a single species occurs if the nutrient supply of an empty habitat allows it to acquire a threshold of stored nutrient quota, sufficient to overcome loss to outflow after accounting for the cost of toxin production. For the two-species system, a semitrivial equilibrium with one species resident is unstable to invasion by the missing species according to a similar threshold condition. The invader increases if acquires a stored nutrient quota sufficient to overcome loss to outflow and toxin-induced mortality, after accounting for the cost of the invader's own toxin production. If both semitrivial equilibria for the two-species system are invasible then there is at least one coexistence equilibrium. Numerical analyses indicate another possibility: bistability in which both semitrivial equilibria are stable against invasion. In such a case there is competitive exclusion of one species, whose identity depends on initial conditions. When there is a tradeoff between abilities to compete for the nutrient and to compete through toxicity, the more toxic species can dominate only under nutrient-rich conditions. Bistability under such conditions could contribute to the unpredictability of toxic algal blooms. PMID:23660151

Grover, James P; Wang, Feng-Bin

2013-08-01

361

The effect of the nutrient intensity and buffering power of a soil, and the absorbing power, size and root hairs of a root, on nutrient absorption by diffusion  

Microsoft Academic Search

Summary A portion of a single plant root is treated as an absorbing cylindrical sink to which nutrients move by diffusion. Assuming that the rate of uptake of nutrient is proportional to its concentration at the root surface, and that the nutrient, though reacting with the solid, moves only through the soil solution, standard diffusion equations are used to calculate

P. H. Nye

1966-01-01

362

Method and apparatus for determining nutrient stimulation of biological processes  

DOEpatents

A method and apparatus is described for determining the nutrients to stimulate microorganisms in a particular environment. A representative sample of microorganisms from a particular environment are contacted with multiple support means wherein each support means has intimately associated with the surface of the support means a different nutrient composition for said microorganisms in said sample. The multiple support means is allowed to remain in contact with the microorganisms in the sample for a time period sufficient to measure differences in microorganism effects for the multiple support means. Microorganism effects for the multiple support means are then measured and compared. The invention is particularly adaptable to being conducted in situ. The additional steps of regulating nutrients added to the particular environment of microorganisms can enhance the desired results. Biological systems particularly suitable for this invention are bioremediation, biologically enhanced oil recovery, biological leaching of metals, and agricultural bioprocesses. 5 figs.

Colwell, F.S.; Geesey, G.G.; Gillis, R.J.; Lehman, R.M.

1997-11-11

363

World fertilizer nutrient reserves: a view to the future.  

PubMed

The increasing need for food production in subtropical regions likely translates to a need for additional plant nutrients. As a consequence, knowledge of world fertilizer nutrient reserves is of particular relevance to sustainable agriculture in the subtropics. The stewardship responsibilities of agriculture include the wise use of the raw materials from which commercial fertilizers are produced. Development and implementation of fertilizer best management practices with focus on the 4Rs-right source, right rate, right time, right place-are timely not only for short-term economic and environmental reasons, but also for the wise stewardship of the non-renewable nutrient resources upon which food, feed, fiber, and fuel production depend. PMID:22415449

Fixen, Paul E; Johnston, Adrian M

2012-03-30

364

The role of carbon in fungal nutrient uptake and transport  

PubMed Central

The arbuscular mycorrhizal (AM) symbiosis, which forms between plant hosts and ubiquitous soil fungi of the phylum Glomeromycota, plays a key role for the nutrient uptake of the majority of land plants, including many economically important crop species. AM fungi take up nutrients from the soil and exchange them for photosynthetically fixed carbon from the host. While our understanding of the exact mechanisms controlling carbon and nutrient exchange is still limited, we recently demonstrated that (i) carbon acts as an important trigger for fungal N uptake and transport, (ii) the fungus changes its strategy in response to an exogenous supply of carbon, and that (iii) both plants and fungi reciprocally reward resources to those partners providing more benefit. Here, we summarize recent research findings and discuss the implications of these results for fungal and plant control of resource exchange in the AM symbiosis.

Fellbaum, Carl R.; Mensah, Jerry A.; Pfeffer, Philip E.; Kiers, E. Toby; Bucking, Heike

2012-01-01

365

Microbial community composition in sediments resists perturbation by nutrient enrichment  

PubMed Central

Functional redundancy in bacterial communities is expected to allow microbial assemblages to survive perturbation by allowing continuity in function despite compositional changes in communities. Recent evidence suggests, however, that microbial communities change both composition and function as a result of disturbance. We present evidence for a third response: resistance. We examined microbial community response to perturbation caused by nutrient enrichment in salt marsh sediments using deep pyrosequencing of 16S rRNA and functional gene microarrays targeting the nirS gene. Composition of the microbial community, as demonstrated by both genes, was unaffected by significant variations in external nutrient supply in our sampling locations, despite demonstrable and diverse nutrient-induced changes in many aspects of marsh ecology. The lack of response to external forcing demonstrates a remarkable uncoupling between microbial composition and ecosystem-level biogeochemical processes and suggests that sediment microbial communities are able to resist some forms of perturbation.

Bowen, Jennifer L; Ward, Bess B; Morrison, Hilary G; Hobbie, John E; Valiela, Ivan; Deegan, Linda A; Sogin, Mitchell L

2011-01-01

366

Setting nutrient thresholds to support an ecological assessment based on nutrient enrichment, potential primary production and undesirable disturbance.  

PubMed

The EU Water Framework Directive recognises that ecological status is supported by the prevailing physico-chemical conditions in each water body. This paper describes an approach to providing guidance on setting thresholds for nutrients taking account of the biological response to nutrient enrichment evident in different types of water. Indices of pressure, state and impact are used to achieve a robust nutrient (nitrogen) threshold by considering each individual index relative to a defined standard, scale or threshold. These indices include winter nitrogen concentrations relative to a predetermined reference value; the potential of the waterbody to support phytoplankton growth (estimated as primary production); and detection of an undesirable disturbance (measured as dissolved oxygen). Proposed reference values are based on a combination of historical records, offshore (limited human influence) nutrient concentrations, literature values and modelled data. Statistical confidence is based on a number of attributes, including distance of confidence limits away from a reference threshold and how well the model is populated with real data. This evidence based approach ensures that nutrient thresholds are based on knowledge of real and measurable biological responses in transitional and coastal waters. PMID:17045302

Devlin, Michelle; Painting, Suzanne; Best, Mike

2007-01-01

367

Shedding light onto nutrient responses of arbuscular mycorrhizal plants: nutrient interactions may lead to unpredicted outcomes of the symbiosis.  

PubMed

The role and importance of arbuscular mycorrhizae (AM) in plant nitrogen (N) nutrition is uncertain. We propose that this be clarified by using more integrative experimental designs, with the use of a gradient of N supply and the quantification of an extensive array of plant nutrient contents. Using such an experimental design, we investigated AM effects on plant N nutrition, whether the mycorrhizal N response (MNR) determines the mycorrhizal growth response (MGR), and how MNR influences plants' C economy. Oryza sativa plants were inoculated with Rhizophagus irregularis or Funneliformis mossae. AM effects were studied along a gradient of N supplies. Biomass, photosynthesis, nutrient and starch contents, mycorrhizal colonization and OsPT11 gene expression were measured. C investment in fungal growth was estimated. Results showed that, in rice, MGR was dependent on AM nutrient uptake effects, namely on the synergy between N and Zn, and not on C expenditure. The supply of C to the fungus was dependent on the plant's nutrient demand, indicated by high shoot C/N or low %N. We conclude that one of the real reasons for the negative MGR of rice, Zn deficiency of AMF plants, would have remained hidden without an experimental design allowing the observation of plants' response to AM along gradients of nutrient concentrations. Adopting more integrative and comprehensive experimental approaches in mycorrhizal studies seems therefore essential if we are to achieve a true understanding of AM function, namely of the mechanisms of C/N exchange regulation in AM. PMID:24656333

Corrêa, Ana; Cruz, Cristina; Pérez-Tienda, Jacob; Ferrol, Nuria

2014-05-01

368

Evidence for sensitivity of dune wetlands to groundwater nutrients.  

PubMed

Dune slacks are seasonal wetlands, high in biodiversity, which experience considerable within-year and between-year variations in water-table. They are subject to many pressures including climate change, land use change and eutrophication. Despite their biological importance and the threats facing them, the hydrological and nutrient parameters that influence their soil properties and biodiversity are poorly understood and there have been no empirical studies to date testing for biological effects in dune systems resulting from groundwater nutrients at low concentrations. In this study we examined the impact of groundwater nutrients on water chemistry, soil chemistry and vegetation composition of dune slacks at three distance classes (0-150m, 150-300m, 300-450m) away from known (off-site) nutrient sources at Aberffraw dunes in North Wales, whilst accounting for differences in water-table regime. Groundwater nitrate and dissolved inorganic nitrogen (DIN) and soil nitrate and nitrite all had significantly higher concentrations closest to the nutrient source. Multivariate analysis showed that although plant species composition within this site was primarily controlled by water table depth and water table fluctuation, nitrogen from groundwater also influenced species composition, independently of water table and soil development. A model containing all hydrological parameters explained 17% of the total species variance; an additional 7% was explained following the addition of NO3 to this model. Areas exposed to elevated, but still relatively low, groundwater nutrient concentrations (mean 0.204mg/L+/-0.091 of DIN) had greater abundance of nitrophilous species and fewer basipholous species than in areas with lower concentrations. This shows that clear biological impact occurs below previously suggested DIN thresholds of 0.20-0.40 (mg/L). PMID:24846404

Rhymes, Jennifer; Wallace, Hilary; Fenner, Nathalie; Jones, Laurence

2014-08-15

369

Nutrient leaching in a Colombian savanna Oxisol amended with biochar.  

PubMed

Nutrient leaching in highly weathered tropical soils often poses a challenge for crop production. We investigated the effects of applying 20 t ha biochar (BC) to a Colombian savanna Oxisol on soil hydrology and nutrient leaching in field experiments. Measurements were made over the third and fourth years after a single BC application. Nutrient contents in the soil solution were measured under one maize and one soybean crop each year that were routinely fertilized with mineral fertilizers. Leaching by unsaturated water flux was calculated using soil solution sampled with suction cup lysimeters and water flux estimates generated by the model HYDRUS 1-D. No significant difference ( > 0.05) was observed in surface-saturated hydraulic conductivity or soil water retention curves, resulting in no relevant changes in water percolation after BC additions in the studied soils. However, due to differences in soil solution concentrations, leaching of inorganic N, Ca, Mg, and K measured up to a depth of 0.6 m increased ( < 0.05), whereas P leaching decreased, and leaching of all nutrients (except P) at a depth of 1.2 m was significantly reduced with BC application. Changes in leaching at 2.0 m depth with BC additions were about one order of magnitude lower than at other depths, except for P. Biochar applications increased soil solution concentrations and downward movement of nutrients in the root zone and decreased leaching of Ca, Mg, and Sr at 1.2 m, possibly by a combination of retention and crop nutrient uptake. PMID:22751049

Major, Julie; Rondon, Marco; Molina, Diego; Riha, Susan J; Lehmann, Johannes

2012-01-01

370

Predator-Driven Nutrient Recycling in California Stream Ecosystems  

PubMed Central

Nutrient recycling by consumers in streams can influence ecosystem nutrient availability and the assemblage and growth of photoautotrophs. Stream fishes can play a large role in nutrient recycling, but contributions by other vertebrates to overall recycling rates remain poorly studied. In tributaries of the Pacific Northwest, coastal giant salamanders (Dicamptodon tenebrosus) occur at high densities alongside steelhead trout (Oncorhynchus mykiss) and are top aquatic predators. We surveyed the density and body size distributions of D. tenebrosus and O. mykiss in a California tributary stream, combined with a field study to determine mass-specific excretion rates of ammonium (N) and total dissolved phosphorus (P) for D. tenebrosus. We estimated O. mykiss excretion rates (N, P) by bioenergetics using field-collected data on the nutrient composition of O. mykiss diets from the same system. Despite lower abundance, D. tenebrosus biomass was 2.5 times higher than O. mykiss. Mass-specific excretion summed over 170 m of stream revealed that O. mykiss recycle 1.7 times more N, and 1.2 times more P than D. tenebrosus, and had a higher N:P ratio (8.7) than that of D. tenebrosus (6.0), or the two species combined (7.5). Through simulated trade-offs in biomass, we estimate that shifts from salamander biomass toward fish biomass have the potential to ease nutrient limitation in forested tributary streams. These results suggest that natural and anthropogenic heterogeneity in the relative abundance of these vertebrates and variation in the uptake rates across river networks can affect broad-scale patterns of nutrient limitation.

Munshaw, Robin G.; Palen, Wendy J.; Courcelles, Danielle M.; Finlay, Jacques C.

2013-01-01

371

Nutrient-dependent/pheromone-controlled adaptive evolution: a model  

PubMed Central

Background The prenatal migration of gonadotropin-releasing hormone (GnRH) neurosecretory neurons allows nutrients and human pheromones to alter GnRH pulsatility, which modulates the concurrent maturation of the neuroendocrine, reproductive, and central nervous systems, thus influencing the development of ingestive behavior, reproductive sexual behavior, and other behaviors. Methods This model details how chemical ecology drives adaptive evolution via: (1) ecological niche construction, (2) social niche construction, (3) neurogenic niche construction, and (4) socio-cognitive niche construction. This model exemplifies the epigenetic effects of olfactory/pheromonal conditioning, which alters genetically predisposed, nutrient-dependent, hormone-driven mammalian behavior and choices for pheromones that control reproduction via their effects on luteinizing hormone (LH) and systems biology. Results Nutrients are metabolized to pheromones that condition behavior in the same way that food odors condition behavior associated with food preferences. The epigenetic effects of olfactory/pheromonal input calibrate and standardize molecular mechanisms for genetically predisposed receptor-mediated changes in intracellular signaling and stochastic gene expression in GnRH neurosecretory neurons of brain tissue. For example, glucose and pheromones alter the hypothalamic secretion of GnRH and LH. A form of GnRH associated with sexual orientation in yeasts links control of the feedback loops and developmental processes required for nutrient acquisition, movement, reproduction, and the diversification of species from microbes to man. Conclusion An environmental drive evolved from that of nutrient ingestion in unicellular organisms to that of pheromone-controlled socialization in insects. In mammals, food odors and pheromones cause changes in hormones such as LH, which has developmental affects on pheromone-controlled sexual behavior in nutrient-dependent reproductively fit individuals across species of vertebrates.

Kohl, James Vaughn

2013-01-01

372

Nutrient leaching from mixed-species Florida residential landscapes.  

PubMed

Nutrient losses from residential lawns and landscapes can negatively impact water quality. Information about nutrient leaching from established residential landscapes containing a mixture of woody ornamental plants and turfgrass is limited. The objective of our study was to determine the effect of vegetation cover (turfgrass vs. woody ornamental) on nutrient leaching from established landscapes. Nine drainage lysimeters were planted with three vegetation treatments with the following coverage: (i) 60% turfgrass, 40% ornamental; (ii) 75% turfgrass, 25% ornamental; and (iii) 90% turfgrass, 10% ornamental. Daily leachate samples were collected and combined to produce weekly flow-weighted samples for 1 yr. Leachate samples were analyzed for total Kjeldahl N (TKN), nitrate (+ nitrite)-N (NO), ammonium-N (NH-N), and dissolved reactive phosphorus (DRP). The ratio of actual evapotranspiration (ET) to reference evapotranspiration (ET) was similar among treatments. However, drainage from the 90% turfgrass lysimeters was periodically higher than from the 60 and/or 75% turfgrass treatments. In most cases, leachate N and P concentrations and loads followed the same trend as drainage. The addition of shrubs in the 60 and 75% turfgrass treatments reduced leachate when rainfall was low and irrigation was the main water input. We suggest that established woody ornamental plants are more effective at absorbing water and nutrients than turfgrass due, in part, to increased root biomass and deeper rooting of established woody plants, which allows for more efficient uptake of soil water and nutrients. The use of woody plants in residential landscapes can reduce nutrient leaching in urban areas. PMID:24216431

Qin, Zhixuan; Shober, Amy L; Beeson, Richard C; Wiese, Christine

2013-09-01

373

The last generation of bacterial growth in limiting nutrient  

PubMed Central

Background Bacterial growth as a function of nutrients has been studied for decades, but is still not fully understood. In particular, the growth laws under dynamically changing environments have been difficult to explore, because of the rapidly changing conditions. Here, we address this challenge by means of a robotic assay and measure bacterial growth rate, promoter activity and substrate level at high temporal resolution across the entire growth curve in batch culture. As a model system, we study E. coli growing under nitrogen or carbon limitation, and explore the dynamics in the last generation of growth where nutrient levels can drop rapidly. Results We find that growth stops abruptly under limiting nitrogen or carbon, but slows gradually when nutrients are not limiting. By measuring growth rate at a 3 min time resolution, and inferring the instantaneous substrate level, s, we find that the reduction in growth rate ? under nutrient limitation follows Monod’s law, ?=?0sks+s. By following promoter activity of different genes we found that the abrupt stop of growth under nitrogen or carbon limitation is accompanied by a pulse-like up-regulation of the expression of genes in the relevant nutrient assimilation pathways. We further find that sharp stop of growth is conditional on the presence of regulatory proteins in the assimilation pathway. Conclusions The observed sharp stop of growth accompanied by a pulsed expression of assimilation genes allows bacteria to compensate for the drop in nutrients, suggesting a strategy used by the cells to prolong exponential growth under limiting substrate.

2013-01-01

374

Nutrient pressures and ecological responses to nutrient loading reductions in Danish streams, lakes and coastal waters  

NASA Astrophysics Data System (ADS)

The Danish National Aquatic Monitoring and Assessment Programme (NOVA) was launched in 1988 following the adoption of the first Danish Action Plan on the Aquatic Environment in 1987 with the aim to reduce by 50% the nitrogen (N) loading and by 80% the phosphorus (P) loading to the aquatic environment. The 14 years of experience gathered from NOVA have shown that discharges of total N (TN) and P (TP) from point sources to the Danish Aquatic Environment have been reduced by 69% (N) and 82% (P) during the period 1989 2002. Consequently, the P concentration has decreased markedly in most Danish lakes and estuaries. Considerable changes in agricultural practice have resulted in a reduction of the net N-surplus from 136 to 88 kg N ha-1 yr-1 (41%) and the net P-surplus from 19 to 11 kg P ha-1 yr-1 (42%) during the period 1985 2002. Despite these efforts Danish agriculture is today the major source of both N (>80%) and P (>50%) in Danish streams, lakes and coastal waters. A non-parametric statistical trend analysis of TN concentrations in streams draining dominantly agricultural catchments has shown a significant (p<0.05) downward trend in 48 streams with the downward trend being stronger in loamy compared to sandy catchments, and more pronounced with increasing dominance of agricultural exploitation in the catchments. In contrast, a statistical trend analysis of TP concentrations in streams draining agricultural catchments did not reveal any significant trends. The large reduction in nutrient loading from point and non-point sources has in general improved the ecological conditions of Danish lakes in the form of increased summer Secchi depth, decreased chlorophyll a and reduced phytoplankton biomass. Major changes have also occurred in the fish communities in lakes, with positive cascading effects on water quality. In Danish estuaries and coastal waters only a few significant improvements in the ecological quality have been observed, although it is expected that the observed reduced nutrient concentrations are likely to improve the ecological quality of estuaries and coastal waters in Denmark in the long term.

Kronvang, Brian; Jeppesen, Erik; Conley, Daniel J.; Søndergaard, Martin; Larsen, Søren E.; Ovesen, Niels B.; Carstensen, Jacob

2005-03-01

375

Defining powerhouse fruits and vegetables: a nutrient density approach.  

PubMed

National nutrition guidelines emphasize consumption of powerhouse fruits and vegetables (PFV), foods most strongly associated with reduced chronic disease risk; yet efforts to define PFV are lacking. This study developed and validated a classification scheme defining PFV as foods providing, on average, 10% or more daily value per 100 kcal of 17 qualifying nutrients. Of 47 foods studied, 41 satisfied the powerhouse criterion and were more nutrient-dense than were non-PFV, providing preliminary evidence of the validity of the classification scheme. The proposed classification scheme is offered as a tool for nutrition education and dietary guidance. PMID:24901795

Di Noia, Jennifer

2014-01-01

376

Through form to function: root hair development and nutrient uptake  

NASA Technical Reports Server (NTRS)

Root hairs project from the surface of the root to aid nutrient and water uptake and to anchor the plant in the soil. Their formation involves the precise control of cell fate and localized cell growth. We are now beginning to unravel the complexities of the molecular interactions that underlie this developmental regulation. In addition, after years of speculation, nutrient transport by root hairs has been demonstrated clearly at the physiological and molecular level, with evidence for root hairs being intense sites of H(+)-ATPase activity and involved in the uptake of Ca(2+), K(+), NH(4)(+), NO(3)(-), Mn(2+), Zn(2+), Cl(-) and H(2)PO(4)(-).

Gilroy, S.; Jones, D. L.

2000-01-01

377

Defining Powerhouse Fruits and Vegetables: A Nutrient Density Approach  

PubMed Central

National nutrition guidelines emphasize consumption of powerhouse fruits and vegetables (PFV), foods most strongly associated with reduced chronic disease risk; yet efforts to define PFV are lacking. This study developed and validated a classification scheme defining PFV as foods providing, on average, 10% or more daily value per 100 kcal of 17 qualifying nutrients. Of 47 foods studied, 41 satisfied the powerhouse criterion and were more nutrient-dense than were non-PFV, providing preliminary evidence of the validity of the classification scheme. The proposed classification scheme is offered as a tool for nutrition education and dietary guidance.

2014-01-01

378

Dust or Crust?: Surface Soil Nutrients in the Kalahari  

NASA Astrophysics Data System (ADS)

The Kalahari covers 2.5 million km2 of southern Africa and consists of 95% fine sand-sized, aeolian-deposited sediment. Soils are predominantly deep, structureless and lacking in N, P and organic matter. Plant available nutrients are concentrated in the top centimetre and thus vulnerable to degradation and transportation by wind erosion. The fertility of Kalahari soils is important for nutritious grass production as livestock grazing remains the predominant livelihood throughout the region. The aim of the research was to investigate the interrelationships between dust, biological crusts, vegetation and disturbance across the Kalahari. Crust, vegetation and surface nutrient characteristics were determined at five locations of different land uses. The spatial and temporal variability of rainfall results in an incomplete vegetation cover and spatially heterogeneous soil nutrients. Our studies show that nutrient heterogeneity is controlled by various factors operating at different scales and is important for ecosystem functioning and degradation vulnerability. At a landscape scale, variability is minimal due to limited topography and a relatively uniform Kalahari Sand cover. At a smaller scale, spatial heterogeneity of soil N and P is also low (11 to 28%) compared to shrublands in the SW United States. Wind erosion is not the principal cause of nutrient heterogeneity because the amount of dust movement and associated nutrient fluxes are low. This is because of an extensive vegetation cover that reduces erodibility and coarse grain sizes, aggregation and biological crusts which reduce surface erosivity. Enrichment occurs under bush canopies due to organic inputs from the vegetation as well as fixation by biological soil crusts that develop preferentially in protected sub-canopy niches. Biological soil crusts are widespread and are able to persist in landscapes where there is a high level of disturbance. However, crust composition is largely restricted to simple Microcoleus spp. Crustal succession is limited by both breakage of crusts and burial by wind blown sediment. In a typical communal grazing area, 48% of the surface was unconsolidated, 44% was crusted and 8% buried crusts compared to up to 95% crust cover in National Parks. Bush sub-canopies are sites of preferential crust development and thus nutrient enrichment, but are also subjected to periodic burial by wind blown dust and plant litter. The overall impact on surface nutrients will depend upon the bush species composition, canopy structure and degree of disturbance.

Thomas, A. D.; Dougill, A. J.

2003-12-01

379

Mathematical modelling of plant water and nutrient uptake  

NASA Astrophysics Data System (ADS)

In this presentation I will describe a model of plant water and nutrient uptake and how to translate this model and experimental data from the single root scale to the root branching structure scale. The model starts at the single root scale and describes the water and nutrient movement in the soil using Richards' equation (water uptake) and diffusion-convection equation (nutrient uptake). The water and nutrient uptake in the single root scale model is represented by boundary conditions. In the case of nutrient uptake this has the form of a non-linear Michaelis-Menten uptake law and in the case of water this is given by a soil-xylem pressure difference boundary condition. The flow of water in the xylem is modeled as Poiseuille flow. We solve the single root scale models using the analytic approximate technique of asymptotic expansions similar to Oseen expansions known from fluid dynamics. We will then discuss how to use the analytic expression to estimate the water and nutrient uptake by growing root branching systems. We model the growth of the root system using a dynamic population model to describe the branching and elongation of roots in the branching system. This root branching population model results in a hyperbolic equation similar to age dependent population models and it can be solved fully analytically using the method of characteristics. Thus we have a fully analytic description of the root branching system evolution. We use this branching model to estimate the nutrient uptake in a scenario when the competition between subbranches is small, i.e., as it is in the case of phosphate, potassium and arsenic. We compare our approximate analytic model to a full 3d simulation of the root system phosphate uptake and find that the analytic model almost perfectly reproduces the 3d numerical model. In addition the analytic model can be included in larger field/catchment/climate scale models something which is not practically possible with the numerical simulations due to their high computational burden. As a further development of the analytic model we extend it to take into account more details about the root morphology, such as the branching angle between roots, to calculate the evolution of the soil moisture and nutrient concentration profiles due to surface fertilisation and rainfall events. Using this model we are able to determine the relationship between the rainfall events and fertiliser movement into the soil profile. We find that there is a critical rate of rainfall below which the fertilizer (or pollutant) movement into the deeper layers of the soil is impeded due to the development of a slowly varying fluid saturation profile.

Roose, Tiina

2010-05-01

380

Recovery of dairy manure nutrients by benthic freshwater algae.  

PubMed

Harnessing solar energy to grow algal biomass on wastewater nutrients could provide a holistic solution to nutrient management problems on dairy farms. The production of algae from a portion of manure nutrients to replace high-protein feed supplements which are often imported (along with considerable nutrients) onto the farm could potentially link consumption and supply of on-farm nutrients. The objective of this research was to assess the ability of benthic freshwater algae to recover nutrients from dairy manure and to evaluate nutrient uptake rates and dry matter/crude protein yields in comparison to a conventional cropping system. Benthic algae growth chambers were operated in semi-batch mode by continuously recycling wastewater and adding manure inputs daily. Using total nitrogen (TN) loading rates of 0.64-1.03 g m(-2) d(-1), the dried algal yields were 5.3-5.5 g m(-2) d(-1). The dried algae contained 1.5-2.1% P and 4.9-7.1% N. At a TN loading rate of 1.03 g m(-2) d(-1), algal biomass contained 7.1% N compared to only 4.9% N at a TN loading rate of 0.64 g m(-2) d(-1). In the best case, algal biomass had a crude protein content of 44%, compared to a typical corn silage protein content of 7%. At a dry matter yield of 5.5 g m(-2) d(-1), this is equivalent to an annual N uptake rate of 1,430 kg ha(-1) yr(-1). Compared to a conventional corn/rye rotation, such benthic algae production rates would require 26% of the land area requirements for equivalent N uptake rates and 23% of the land area requirements on a P uptake basis. Combining conventional cropping systems with an algal treatment system could facilitate more efficient crop production and farm nutrient management, allowing dairy operations to be environmentally sustainable on fewer acres. PMID:12137274

Wilkie, Ann C; Mulbry, Walter W

2002-08-01

381

A new compensated root water and nutrient uptake model implemented in HYDRUS programs  

NASA Astrophysics Data System (ADS)

Plant root water and nutrient uptake is one of the most important processes in subsurface unsaturated flow and transport modeling, as root uptake controls actual plant evapotranspiration, water recharge and nutrient leaching to the groundwater. Root water uptake in unsaturated flow models is usually uncompensated and nutrient uptake is simulated assuming that all uptake is passive. We present a new compensated root water and nutrient uptake model, implemented in HYDRUS programs. The so-called root adaptability factor (Jarvis, 1989) is used to represent a threshold value above which reduced root water or nutrient uptake in water- or nutrient-stressed parts of the root zone is fully compensated for by increased uptake in other soil regions that are less stressed. Using a critical value of the water stress index, water uptake compensation is proportional to the water stress response function. Total root nutrient uptake is determined from the total of active and passive nutrient uptake. The partitioning between passive and active uptake is controlled by the a priori defined concentration value c_max. Passive nutrient uptake is simulated by multiplying root water uptake with the dissolved nutrient concentration, for soil solution concentration values below c_max. Passive nutrient uptake is thus zero when c_max is equal to zero. As the active nutrient uptake is obtained from the difference between plant nutrient demand and passive nutrient uptake (using Michaelis-Menten kinetics), the presented model thus implies that reduced passive nutrient uptake is compensated for by active nutrient uptake. In addition, the proposed root uptake model includes compensation for active nutrient uptake, in a similar way as used for root water uptake. The proposed root water and nutrient uptake model is demonstrated by several hypothetical and real examples, for plants supplied by water due to capillary rise from groundwater and surface drip irrigation.

Simunek, Jiri; Hopmans, Jan W.; Lazarovitch, Naftali

2010-05-01

382

Acumulação de nutrientes em mudas de moringa ( Moringa oleifera Lam) sob omissão de macronutrientes1  

Microsoft Academic Search

Resumo - A Moringa oleifera Lam. é uma espécie arbórea pertencente à família Moringaceae, adaptada às condi- ções áridas e semi-áridas e de uso diversificado com especial destaque na ornamentação de parques e jardins, na alimentação animal, na complementação alimentar humana e na medicina. Uma vez que são poucas as informações sobre essa planta, o trabalho teve como objetivo avaliar

Hugo Vieira; Lucia Helena; Garófalo Chaves; Ricardo Almeida Viégas

2008-01-01

383

Phytoplankton growth on organic nutrients from trash fish  

Microsoft Academic Search

Trash fish is common feed for caged fish in marine aquaculture. Most feed is not eaten and enters the water surrounding fish farms. The organic matter in trash fish is a nutrient source contributing to aquatic eutrophication impacts such as algal blooms and low oxygen. The objective of this study was to examine whether phytoplankton utilized organic matter of trash

Yongli Gao; Kedong Yin; Lei He; Paul J. Harrison

2012-01-01

384

Aquaponic Systems: Nutrient recycling from fish wastewater by vegetable production  

Microsoft Academic Search

This chapter describes the possibility to combine wastewater treatment in recirculating aquaculture systems (RAS) with the production of crop plants biomass. In an aquaponic RAS established in Waedenswil, Zurich, the potential of three crop plants was assessed to recycle nutrients from fish wastewater. A special design of trickling filters was used to provide nitrification of fish wastewater: Light-expanded clay aggregate

Andreas Graber; Ranka Junge

2009-01-01

385

Nutrients and the Great Lakes Nearshore, Circa 2002-2007  

EPA Science Inventory

Nearshore nutrient impressions were largely limited to observations of local spatial trends from a few site-specific studies and some temporal trends at a set of Canadian water intake locations (later summarized in Nicholls et al. 1999). Lacking a systematic information base fo...

386

Nutrient resupplementation arrests bio-oil accumulation in Phaeodactylum tricornutum.  

PubMed

Phaeodactylum tricornutum is a marine diatom in the class Bacillariophyceae and is important ecologically and industrially with regards to ocean primary production and lipid accumulation for biofuel production, respectively. Triacylglyceride (TAG) accumulation has been reported in P. tricornutum under different nutrient stresses, and our results show that lipid accumulation can occur with nitrate or phosphate depletion. However, greater lipid accumulation was observed when both nutrients were depleted as observed using a Nile Red assay and fatty acid methyl ester (FAME) profiles. Nitrate depletion had a greater effect on lipid accumulation than phosphate depletion. Lipid accumulation in P. tricornutum was arrested upon resupplementation with the depleted nutrient. Cells depleted of nitrogen showed a distinct shift from a lipid accumulation mode to cellular growth post-resupplementation with nitrate, as observed through increased cell numbers and consumption of accumulated lipid. Phosphate depletion caused lipid accumulation that was arrested upon phosphate resupplementation. The cessation of lipid accumulation was followed by lipid consumption without an increase in cell numbers. Cells depleted in both nitrate and phosphate displayed cell growth upon the addition of both nitrate and phosphate and had the largest observed lipid consumption upon resupplementation. These results indicate that phosphate resupplementation can shut down lipid accumulation but does not cause cells to shift into cellular growth, unlike nitrate resupplementation. These data suggest that nutrient resupplementation will arrest lipid accumulation and that switching between cellular growth and lipid accumulation can be regulated upon the availability of nitrogen and phosphorus. PMID:23771779

Valenzuela, J; Carlson, R P; Gerlach, R; Cooksey, K; Peyton, B M; Bothner, B; Fields, M W

2013-08-01

387

Nerveless and gutsy: intestinal nutrient sensing from invertebrates to humans.  

PubMed

The increasingly recognized role of gastrointestinal signals in the regulation of food intake, insulin production and peripheral nutrient storage has prompted a surge of interest in studying how the gastrointestinal tract senses and responds to nutritional information. Identification of metabolically important intestinal nutrient sensors could provide potential new drug targets for the treatment of diabetes, obesity and gastrointestinal disorders. From a more fundamental perspective, the study of intestinal chemosensation is revealing novel, non-neuronal modes of communication involving differentiated epithelial cells. It is also identifying signalling mechanisms downstream of not only canonical receptors but also nutrient transporters, thereby supporting a chemosensory role for "transceptors" in the intestine. This review describes known and proposed mechanisms of intestinal carbohydrate, protein and lipid sensing, best characterized in mammalian systems. It also highlights the potential of invertebrate model systems such as C. elegans and Drosophila melanogaster by summarizing known examples of molecular evolutionary conservation. Recently developed genetic tools in Drosophila, an emerging model system for the study of physiology and metabolism, allow the temporal, spatial and high-throughput manipulation of putative intestinal sensors. Hence, fruit flies may prove particularly suited to the study of the link between intestinal nutrient sensing and metabolic homeostasis. PMID:22248674

Miguel-Aliaga, Irene

2012-08-01

388

Phycoremediation: key issues for cost-effective nutrient removal processes.  

PubMed

Phycoremediation applied to the removal of nutrients from animal wastewater and other high organic content wastewater is a field with a great potential and demand considering that surface and underground water bodies in several regions of the world are suffering of eutrophication. However, the development of more efficient nutrient removal algal systems requires further research in key areas. Algae growth rate controls directly and indirectly the nitrogen and phosphorus removal efficiency. Thus, maximum algae productivity is required for effective nutrient removal and must be considered as a key area of research. Likewise, low harvesting costs are also required for a cost-effective nutrient removal system. The use of filamentous microalgae with a high autoflocculation capacity and the use of immobilized cells have been investigated in this respect. Another key area of research is the use of algae strains with special attributes such as tolerance to extreme temperature, chemical composition with predominance of high added value products, a quick sedimentation behavior, or a capacity for growing mixotrophically. Finally, to combine most of the achievements from key areas and to design integrated recycling systems (IRS) should be an ultimate and rewarding goal. PMID:14623045

Olguín, Eugenia J

2003-12-01

389

FIELD STUDY OF NUTRIENT CONTROL IN A MULTICELL LAGOON  

EPA Science Inventory

This report covers nutrient control in a serially arranged, multicell aerated lagoon system over a three year period. The objective was to develop reliable technology for reducing phosphorus and for converting ammonia-nitrogen to nitrate-nitrogen. A six-cell lagoon was modified i...

390

Got silicon? The non-essential beneficial plant nutrient  

Microsoft Academic Search

Research on a possible nutritional role for the element silicon has been hampered by the diverse beneficial effects that it has on monocots and dicots, and the subsequent difficulties in focusing studies on a single genetic model system. Although deemed a non-essential nutrient for the majority of plants, the benefits of silicon include increasing pest and pathogen resistance, drought and

Kathryn E Richmond; Michael Sussman

2003-01-01

391

Nutrients versus growth factors in mTORC1 activation  

PubMed Central

Growth factors and nutrients regulate the mechanistic target of rapamycin complex 1 (mTORC1) by different mechanisms. The players that link growth factors and mTORC1 activation have been known for several years and mouse models have validated its relevance for human physiology and disease. In contrast to the picture for growth factor signaling, the means by which nutrient availability leads to mTORC1 activation have remained elusive until recently, with the discovery of the Rag GTPases upstream of mTORC1. The Rag GTPases recruit mTORC1 to the outer lysosomal surface, where growth factor signaling and nutrient signaling converge on mTORC1 activation. A mouse model of constitutive RagA activity has revealed qualitative differences between growth factor- and nutrient– dependent regulation of mTORC1. Regulation of mTORC1 activity by the Rag GTPases in vivo is key for enduring early neonatal fasting, showing its importance for mammalian physiology.

Efeyan, Alejo; Sabatini, David M

2013-01-01

392

Overvagningssystem for Naeringsstoffer: Kod (Food Monitoring System for Nutrients: Meat),  

National Technical Information Service (NTIS)

As a part of the food monitoring system for nutrients in the Danish diet, a number of meat and meat products have been examined for energy, protein, fat, carbohydrate, dry matter, ash, B1-, B2- and B6-vitamin, iron, zinc, magnesium, sodium and potassium. ...

K. S. Hansen T. Leth

1989-01-01

393

Characterization of Heat Transfer in Nutrient Materials, Part 2.  

National Technical Information Service (NTIS)

A thermal model is analyzed that takes into account phase changes in the nutrient material. The behavior of fluids in low gravity environments is discussed along with low gravity heat transfer. Thermal contact resistance in the Skylab food heater is analy...

J. E. Cox R. B. Bannerot C. K. Chen L. C. Witte

1973-01-01

394

Changing perceptions of hunger on a high nutrient density diet  

Microsoft Academic Search

BACKGROUND: People overeat because their hunger directs them to consume more calories than they require. The purpose of this study was to analyze the changes in experience and perception of hunger before and after participants shifted from their previous usual diet to a high nutrient density diet. METHODS: This was a descriptive study conducted with 768 participants primarily living in

Joel Fuhrman; Barbara Sarter; Dale Glaser; Steve Acocella

2010-01-01

395

Characterization of heat transfer in nutrient materials, part 1  

NASA Technical Reports Server (NTRS)

The principles involved in food heating are discussed. The food heating system for Skylab is described. Thermal models of nutrient materials are analyzed including models in zero-g and low pressure conditions. Results are presented of parametric studies to establish the effect of individual parameters on the thermal response of the system.

Cox, J. E.; Bannerot, R. B.; Chen, C. K.; Witte, L. C.

1973-01-01

396

Flow Dynamics and Nutrient Reduction in Rain Gardens  

EPA Science Inventory

The hydrological dynamics and changes in stormwater nutrient concentrations within rain gardens were studied by introducing captured stormwater runoff to rain gardens at EPA?s Urban Water Research Facility in Edison, New Jersey. The runoff used in these experiments was collected...

397

Stoichiometric nutrient balance and origin of coastal eutrophication  

Microsoft Academic Search

We present here an analysis of the stoichiometry of dissolved nutrients in 10 large world rivers, Amazon, Changjiang, Huanghe, Mackenzie, Mississippi, Po, Rhine, Seine, Yukon and Zaire, and in two river-dominated coastal ecosystems prone to eutrophication, the northern Adriatic Sea and the northern Gulf of Mexico. Our analysis suggests that proportions of dissolved silica (Si), nitrogen (N) and phosphorous (P)

Dubravko Justi?; Nancy N. Rabalais; R. Eugene Turner

1995-01-01

398

Stream Restoration to Manage Nutrients in Degraded Watersheds  

EPA Science Inventory

Historic land-use change can reduce water quality by impairing the ability of stream ecosystems to efficiently process nutrients such as nitrogen. Study results of two streams (Minebank Run and Big Spring Run) affected by urbanization, quarrying, agriculture, and impoundments in...

399

Long-Term Nutrient Performance in a Bioinfiltration Rain Garden  

EPA Science Inventory

The goals of this study is to gain a better understanding of the nutrients and metals removal mechanisms involved in a bioinfiltration stormwater abatement system, predict the useful life of a bioinfiltration BMP for the removal of certain contaminants and assess toxicity of stor...

400

Modification of inflammatory aspects of immune function by nutrients  

Microsoft Academic Search

The pro-inflammatory cytokines interleukin 1 (IL1) interleukin 6 (IL6) and tumour necrosis factor-? (TNF), and reactive oxygen species (ROS), play a major role in inflammatory aspects of immune function. They are closely linked with pathology in a wide range of diseases and condition which have an inflammatory basis. Alterations in the intake of fats, antioxidant nutrients, protein and specific amino

Robert F Grimble

1998-01-01

401

Nutrient chemistry of the water column of Lake Tanganyika  

Microsoft Academic Search

Lake Tanganyika shows pcrmancnt thermal stratification with deep-water temperatures that have been stable over the period of observation (since 1939). The lake is anoxic below - 150-m depth. In general the nutrients show Redficld behavior save in the deep waters of the northern basin where large excesses of phosphate and ammonia are prcscnt. Bacterial disproportionation of organic material probably plays

J. M. EDMOND; R. F. STALLARD; H. CRAIG; V. CRAIG; R. F. WEISS; G. W. COULTER

1993-01-01

402

Prediction of Manure and Nutrient Excretion from Dairy Cattle  

Microsoft Academic Search

Accurate estimates of manure excretion are needed for planning manure storage facilities and for nutrient management. Data sets from metabolism studies con- ducted at several universities were compiled and evalu- ated for excretion of total manure, N, P, and K. Animal groups included calves weighing up to 204 kg, heifers weighing between 274 and 613 kg, nonlactating cows, and lactating

T. D. Nennich; J. H. Harrison; L. M. VanWieringen; D. Meyer; A. J. Heinrichs; W. P. Weiss; N. R. St-Pierre; R. L. Kincaid; D. L. Davidson; E. Block

2005-01-01

403

ALGAL RESPONSES TO NUTRIENT LOADING IN GREAT LAKES COASTAL WETLANDS  

EPA Science Inventory

We are evaluating the influence of nutrient loading on phytoplankton and periphyton in coastal wetlands of the Great Lakes as part of an EPA study associated with the Great Lakes Environmental Indicator (GLEI) project. A primary goal is to assess the role of wetland morphology an...

404

Fish as sources and sinks of nutrients in lakes  

Microsoft Academic Search

SUMMARY 1. The release of total phosphorus (TP) and nitrogen (N in ammonium) was measured for the five most abundant fish species (>85% of biomass) in Mouse and Ranger Lakes, two biomanipulated, oligotrophic lakes in Ontario. 2. The specific release rate of both nutrients was significantly related to fish mass; log10 TP release rate (l gh )1) ¼ 0.793 (±0.109)

JEFF M. S EREDA; J EFF J. H UDSON; W ILLIAM; D. T AYLOR; E RIC D EMERS

2008-01-01

405

A Nutrient Combination that Can Affect Synapse Formation  

PubMed Central

Brain neurons form synapses throughout the life span. This process is initiated by neuronal depolarization, however the numbers of synapses thus formed depend on brain levels of three key nutrients—uridine, the omega-3 fatty acid DHA, and choline. Given together, these nutrients accelerate formation of synaptic membrane, the major component of synapses. In infants, when synaptogenesis is maximal, relatively large amounts of all three nutrients are provided in bioavailable forms (e.g., uridine in the UMP of mothers’ milk and infant formulas). However, in adults the uridine in foods, mostly present at RNA, is not bioavailable, and no food has ever been compelling demonstrated to elevate plasma uridine levels. Moreover, the quantities of DHA and choline in regular foods can be insufficient for raising their blood levels enough to promote optimal synaptogenesis. In Alzheimer’s disease (AD) the need for extra quantities of the three nutrients is enhanced, both because their basal plasma levels may be subnormal (reflecting impaired hepatic synthesis), and because especially high brain levels are needed for correcting the disease-related deficiencies in synaptic membrane and synapses.

Wurtman, Richard J.

2014-01-01

406

Radiation Preservation of Foods and Its Effect on Nutrients  

ERIC Educational Resources Information Center

Presents a discussion of (1) some possible applications of ionizing radiation to the treatment and preservation of food and (2) the effects of irradiation on nutrients such as proteins, fats, oils, carbohydrates and vitamins. The authors suggest that the irradiation process has great potential in food technology. Bibliography. (LC)

Josephson, Edward S.; Thomas, Miriam H.

1970-01-01

407

MODELING SEDIMENT-NUTRIENT FLUX AND SEDIMENT OXYGEN DEMAND  

EPA Science Inventory

Depositional flux of particulate organic matter in bottom sediments affects nutrients cycling at the sediment-water interface and consumes oxygen from the overlying water in streams, lakes, and estuaries. This project deals with analytical modeling of nitrogen and carbon producti...

408

The uptake of nutrients from sterilised forest-nursery soils  

Microsoft Academic Search

Soil sterilisation trials were carried out in 7 nurseries in the North and South Islands to test the possibility of increasing productivity by this means. Even where soil pathogens were not a problem seedling growth was improved. Chloropicrin proved more effective than formaldehyde. The greatest increases in growth and nutrient (N, P, and K) uptake occurred in pumice-soil nurseries. However,

G. M. Will

1962-01-01

409

Nutrient removal from eutrophic lake water by wetland filtration  

Microsoft Academic Search

Lake Apopka is a large (125 km2), shallow (mean depth 1.6 m) lake in Florida, USA. The lake was made hypereutrophic by phosphorus loading from floodplain farms and has high levels of nutrients, phytoplankton (Chl a 80 ?g l?1), and suspended matter. The restoration plan developed by the St. Johns River Water Management District encompasses the biomanipulation concept in which

M. F. Coveney; D. L. Stites; E. F. Lowe; L. E. Battoe; R. Conrow

2002-01-01

410

Factors controlling nutrient concentrations in Amazon floodplain lakes  

Microsoft Academic Search

Nutrient chemistry in lakes of the central floodplain of the Amazon River is influenced by the relative mix of waters of river and local origin. At high water the lakes contained primarily river water, lake and river total nitrogen (TN) levels were similar, concentrations of total suspended solids (TSS), soluble reactive phosphorus (SRP), dissolved inorganic nitrogen (DIN), and total phosphorus

BRUCE R. FORSBERG; ALLAN H. DEVOL; JEFFREY E. RICHEY; LUIZ A. MARTINELLI; HUMBERTO DOS SANTOS

1988-01-01

411

Nutrient Dynamics in Flooded Wetlands. II: Model Application  

EPA Science Inventory

In this paper we applied and evaluated the wetland nutrient model described in an earlier paper. Hydrologic and water quality data from a small restored wetland located on Kent Island, Maryland, which is part of the Delmarva Peninsula on the Eastern shores of the Chesapeake Bay...

412

9 CFR 381.413 - Nutrient content claims; general principles.  

Code of Federal Regulations, 2010 CFR

...absent or present in a certain amount (e.g., âhigh in oat branâ); or (ii) Suggests that the product, because of its nutrient content, may be useful in maintaining healthy dietary practices and is made in association with an explicit claim...

2009-01-01

413

Redfield ratios of remineralization determined by nutrient data analysis  

SciTech Connect

A nonlinear inverse method is applied to nutrient data upon approximately 20 neutral surfaces in each of the South Atlantic, Indian, and Pacific basins, between 400 and 4000 m depth. By accounting for the gradients in nutrients due to the mixing of [open quotes]preformed[close quotes] concentrations of the major water masses, the nutrient changes due to biological activity are examined, and the time-mean, basin-wide Redfield ratios calculated. It is found that the P/N/C[sub org]/[sup O][sub 2] ratios of nutrient regeneration between 400 and 4000 m (corrected for the effect of denitrification) are approximately constant with depth and basin, at a value of 1/16[+-]1/117[+-]14/170[+-]10. These ratios agree with those of fresh organic matter, suggesting that the flux of organic material to the deep ocean may be dominated by fast-sinking matter produced by sporadic, high-productivity events. Sedimentary denitrification reduces the N/P utilization ratio to 12 [+-] 2 between 1000 and 3000 m. In the Indian and Pacific basins the C[sub org]/C[sub inorg] regeneration ratio decreases from approximately 7 [+-] 13 at 400 m to 3 [+-] 1 at 1000 m and to 1 [+-] 0.5 at 4000 m, suggesting a significant amount of calcium carbonate dissolution above the calcite lysoclines in the Indian and Pacific oceans. 74 refs., 8 figs., 3 tabs.

Anderson, L.A. (Harvard Univ., Cambridge, MA (United States)); Sarmiento, J.L. (Princeton Univ., NJ (United States))

1994-03-01

414

Nutrient removal from aquaculture wastewater using a constructed wetlands system  

Microsoft Academic Search

Nutrient removal is essential for aquaculture wastewater treatment to protect receiving waters from eutrophication and for potential reuse of the treated water. A pilot-scale wastewater treatment system consisting of a free water surface (FWS) and a subsurface flow (SSF) constructed wetlands arranged in series was operated for around 8 months. The study was conducted to examine system start-up phenomena and

Ying-Feng Lin; Shuh-Ren Jing; Der-Yuan Lee; Tze-Wen Wang

2002-01-01

415

Influences of Eastern Hemlock Mortality on Nutrient Cycling  

Microsoft Academic Search

Mortality of eastern hemlock (Tsuga canadensis (L.) Carriere) may be caused by a variety of agents, but hemlock trees of all sizes over a large geographic area are currently threatened by an outbreak of the hemlock woolly adelgid (HWA: Adelges tsugae Annand) in the eastern United States. In this paper, we review what is currently known about changes in nutrient

Thad E; Jennifer C. Jenkins; Donald J. Leopold; Dudley J. Raynall

416

FUTURE AQUATIC NUTRIENT LIMITATIONS. (R827785E02)  

EPA Science Inventory

Nutrient limitation of phytoplankton growth in aquatic systems is moving towards a higher incidence of P and Si limitation as a result of increased nitrogen loading, a N:P fertilizer use of 26:1 (molar basis), population growth, and relatively stable silicate loading. This res...

417

Salinity–mineral nutrient relations in horticultural crops  

Microsoft Academic Search

The relations between salinity and mineral nutrition of horticultural crops are extremely complex and a complete understanding of the intricate interactions involved would require the input from a multidisciplinary team of scientists. This review addresses the nutrient elements individually and we emphasise research directed towards the organ, whole-plant and field level. We have attempted to synthesise the literature and reconcile

S. r. Grattan; C. m. Grieve

1998-01-01

418

Nutrient limitation of summer phytoplankton growth in Cayuga Lake  

Microsoft Academic Search

The effect on natural phytoplankton populations of various components of a defined culture medium has been assayed by measurement of 14C assimilation under controlled conditions. Phytoplankton populations in Cayuga Lake are at least partially nutrient limited during the period of stable conditions succeeding the vernal bloom. Sodium silicate consistently stimulated photosynthesis in June, July, and August; this is associated with

D. H. HAMILTON

1969-01-01

419

Injection of nutrients and TEAs in clayey soils using electrokinetics  

SciTech Connect

Bioremediation is a cost-effective and attractive technique for cleanup of organic contaminants in high-permeable soils. Difficulties in providing sufficient nutrients and terminal electron acceptors (TEAs) (e.g., nitrate and sulfate) to subsurface contaminant locations preclude its use for in situ biodegradation of organic contaminants in clayey soils. Electrokinetics is shown to be an effective means to inject necessary ionic nutrients and TEAs in clayey soils. Theoretical analysis and experimental results show that electromigration is a significant factor compared with advective transport rate of ions by electroosmosis. Negatively charged nutrients and TEAs could be injected via introducing them at the cathode and vice versa for positively charged ions. Results also indicate that the concentration achievable in the soil depends on the conductivity of the soil and the inlet concentration of the ion to be injected. The higher the soil conductivity and the inlet concentration the higher is the concentration of ionic nutrients and TEAs achievable in the soil. The pH conditions in the soil could be maintained within the range of approximately 6--9 by placing a calcium carbonate layer in the vicinity of the anode.

Thevanayagam, S. [State Univ. of New York, Buffalo, NY (United States). Dept. of Civil, Structural, and Environmental Engineering; Rishindran, T. [Terraprobe, Brampton, Ontario (Canada)

1998-04-01

420

Nutrient Requirements of Suspension Cultures of Soybean Root Cells.  

National Technical Information Service (NTIS)

The nutrient requirements of suspension cultures from soybean root have been investigated, and a simple medium consisting of mineral salts, sucrose, vitamins and 2,4-dichlorophenoxyacetic acid (2,4-D) was designed. The cells required thiamine,2,4-D and am...

O. L. Gamborg R. A. Miller K. Ojima

1968-01-01

421

Physical nutrient transport in the North Atlantic Subtropical Gyre  

NASA Astrophysics Data System (ADS)

Use of the helium-3 flux gauge to estimate the physically mediated flux of new nutrients to the euphotic zone of the North Atlantic subtropical gyre broadly suggests a pathway whereby inorganic nutrients that have been remineralized within the main thermocline may be returned to the seasonally accessible layer in the Sargasso Sea: the so-called "Nutrient Spiral" (Jenkins and Doney (2003), Glob. Biog. Cyc., 17(4), doi:1110.1029/2003GB002085.) The challenge, however, is identifying the exact mechanism whereby this occurs. One possible process is that of "obduction", whereby the combination of strong advection and rapidly deepening winter mixed layers result in the effective outcropping of substantial amounts of thermocline nutrients and tritiugenic helium-3. We present here a quantitative estimate based on hydrographic sections and geostrophic transports of the fluxes and transformations of both tritugenic helium-3 and nitrate within the basin, and attempt to relate these estimates to the specific shallow-water behaviors of these tracers, and their global and regional physical transports. An important constraint for these estimates lies in the evolving distributions of the transient tracers tritium and helium-3. We compare these results with other tracer-based estimates of new, net-community, and export production.

Jenkins, W.; Lott, D. E.

2009-04-01

422

Enhanced TEX biodegradation in nutrient briquet-peat barrier system  

Microsoft Academic Search

A two-layer barrier system has been developed to remediate gasoline-contaminated ground water. This system consists of a nutrient briquet layer to continuously supply nitrate as the electron acceptor for contaminant biodegradation and a peat layer to remove residual nitrate via biological denitrification and residual contaminants by sorption. Nitrate release rates from three different sizes of concrete briquets were used to

Chih-Ming Kao; Robert C. Borden

1997-01-01

423

Morphological responses to nutrient availability in four clonal herbs  

Microsoft Academic Search

This paper examines morphological plasticity of clonal plants of contrasting habitats and of contrasting architectures in response to nutrient supply. The hypotheses were tested that plants from rich habitats possess greater plasticity in response to variation in resource supply than species from poor habitats, and that rhizomatous species are less plastic in their response than stoloniferous species. Two sympodial rhizomatous

Ming Dong; Marinus J. A. Werger

1996-01-01

424

Herbivores and nutrients control grassland plant diversity via light limitation.  

SciTech Connect

Human alterations to nutrient cycles1,2 and herbivore communities3–7 are affecting global biodiversity dramatically2. Ecological theory predicts these changes should be strongly counteractive: nutrient addition drives plant species loss through intensified competition for light, whereas herbivores prevent competitive exclusion by increasing ground-level light, particularly in productive systems8,9. Here we use experimental data spanning a globally relevant range of conditions to test the hypothesis that herbaceous plant species losses caused by eutrophication may be offset by increased light availability due to herbivory. This experiment, replicated in 40 grasslands on 6 continents, demonstrates that nutrients and herbivores can serve as counteracting forces to control local plant diversity through light limitation, independent of site productivity, soil nitrogen, herbivore type and climate. Nutrient addition consistently reduced local diversity through light limitation, and herbivory rescued diversity at sites where it alleviated light limitation. Thus, species loss from anthropogenic eutrophication can be ameliorated in grasslands where herbivory increases ground-level light.

Borer, Elizabeth T. [Department of Ecology, Evolution, and Behavior, University of Minnesota; et al, et al

2014-01-01

425

Nutrient status: a missing factor in phenological and pollen research?  

PubMed

Phenology ranks among the best ecosystem processes for fingerprinting climate change since temperature explains a high percentage of the interannual or spatial variation in phenological onset dates. However, roles of other environmental variables, such as foliar nutrient concentrations, are far from adequately understood. This observational study examined the effects of air temperature and 11 nutrients on spring phenology of Betula pendula Roth (birch) along an urban-rural gradient in Munich, Germany, during the years 2010/2011. Moreover, the influence of temperature, nutrients, and air pollutants (NO2 and O3) on the amounts of pollen and catkin biomass in 2010 was evaluated. In addition to the influence of higher temperatures advancing phenological onset dates, higher foliar concentrations of potassium, boron, zinc, and calcium were statistically significantly linked to earlier onset dates. Since flushing of leaves is a turgor-driven process and all the influential nutrients are involved in cell extension, membrane function, and stability, there might be a reasonable physiological interpretation of the observed association. The amounts of pollen were negatively correlated with temperature, atmospheric NO2, and foliar iron concentration, suggesting that these variables restrict pollen production. The results of this study suggested an influence of nutritional status on both phenology and pollen production. The interaction of urbanization and climate change should be considered in the assessment of the impact of global warming on ecosystems and human health. PMID:23630329

Jochner, Susanne; Höfler, Josef; Beck, Isabelle; Göttlein, Axel; Ankerst, Donna Pauler; Traidl-Hoffmann, Claudia; Menzel, Annette

2013-04-01

426

Nutrient intake and dental caries in the primary dentition  

Microsoft Academic Search

An extensive literature has assessed the influence of diet on dental caries, but to date dietary influences on caries of the primary dentition have not been studied widely. This study examined the role of specific nutrients in the caries experience of preschool children. A total of 628 children ages 2 to 6 years received a dental examination, parent interview, and

Ana Paula; Faria Marques; Louise Brearley Messer

1992-01-01

427

Nutrient limitation and algal blooms in urbanizing tidal creeks  

Microsoft Academic Search

Tidal creeks are commonly found in low energy systems on the East and Gulf Coasts of the United States, and are often subject to intense watershed human development. Many of these creeks are receiving urban and suburban runoff containing nutrients, among other pollutants. During the period 1993–2001, we studied three tidal creeks located in southeastern North Carolina, a rapidly urbanizing

Michael A. Mallin; Douglas C. Parsons; Virginia L. Johnson; Matthew R. McIver; Heather A. CoVan

2004-01-01

428

Temporal Changes in the Spatial Variability of Soil Nutrients.  

National Technical Information Service (NTIS)

This paper reports the temporal changes in the spatial variability of soil nutrient concentrations across a field during the growing season, over a four-year period. This study is part of the Site-Specific Technologies for Agriculture (SST4Ag) precision f...

1999-01-01

429

Temporal Changes in the Spacial Variability of Soil Nutrients  

Microsoft Academic Search

ABSTRACT This paper reports the temporal ,changes ,in the ,spatial variability of soil ,nutrient concentrations across a field during the growing season, over a four-year period. This study is part ,of the ,Site-Specific Technologies for Agriculture (SST4Ag) precision

R. L. Hoskinson; J. R. Hess; R. S. Alessi

1999-01-01

430

Lepidium latifolium : plant nutrient competition-soil interactions  

Microsoft Academic Search

Exotic weeds are invading rangelands of the western United States at unprecedented rates. Understanding plant-soil relationships and competitive interactions of invasive weeds is crucial in long-term control strategies. In a greenhouse experiment, we investigated the influence of soil nutrient depletion on plant growth and plant competition between the exotic invasive weeds, Lepidium latifolium (invading wetlands) and Bromus tectorum (invading a

Robert R. Blank; Robert G. Qualls; James A. Young

2002-01-01

431

NONPOINT SOURCE - STREAM NUTRIENT LEVEL RELATIONSHIPS: A NATIONWIDE STUDY  

EPA Science Inventory

National Eutrophication Survey (NES) data for a nationwide collection of 928 non-point source watersheds were studied for relationships between macro-drainage area characteristics (particularly land use) and nutrient levels in streams. Both the total and inorganic forms of phosph...

432

EFFECT OF MYCORRHIZA ON THE NUTRIENT UPTAKE OF SUGARCANE  

Microsoft Academic Search

Vesicular arbuscular mycorrhizae (VAM) fungi commonly infect plant roots, forming beneficial symbiotic relationships. The primary benefits of VAM plants are the enhanced acquisition and recycling of nutrients, particularly P, as well as soil moisture. This study compared the relationship between soil and leaf chemical elements of sugarcane variety N12 with low and high % mycorrhization (%myc). Seventy-one soil and leaf

S F JAMAL; P CADET; R S RUTHERFORD; C J STRAKER

433

Groundwater and nutrient discharge through karstic coastal springs (Castelló, Spain)  

Microsoft Academic Search

Discharge of groundwater and associated chemical compounds into coastal karstic regions, which are abundant in the Mediterranean basin, is envisaged to be significant. In this study, we evaluate the groundwater discharge and its nutrient load to the open karstic site of Badum (Castelló, East Spain). Salinity profiles evidenced that groundwater discharge from coastal brackish springs causes a buoyant fresher layer,

E. Garcia-Solsona; J. Garcia-Orellana; P. Masqué; V. Rodellas; M. Mejías; B. Ballesteros; J. A. Domínguez

2010-01-01

434

Nerveless and gutsy: intestinal nutrient sensing from invertebrates to humans  

PubMed Central

The increasingly recognized role of gastrointestinal signals in the regulation of food intake, insulin production and peripheral nutrient storage has prompted a surge of interest in studying how the gastrointestinal tract senses and responds to nutritional information. Identification of metabolically important intestinal nutrient sensors could provide potential new drug targets for the treatment of diabetes, obesity and gastrointestinal disorders. From a more fundamental perspective, the study of intestinal chemosensation is revealing novel, non-neuronal modes of communication involving differentiated epithelial cells. It is also identifying signalling mechanisms downstream of not only canonical receptors but also nutrient transporters, thereby supporting a chemosensory role for “transceptors” in the intestine. This review describes known and proposed mechanisms of intestinal carbohydrate, protein and lipid sensing, best characterized in mammalian systems. It also highlights the potential of invertebrate model systems such as C. elegans and Drosophila melanogaster by summarizing known examples of molecular evolutionary conservation. Recently developed genetic tools in Drosophila, an emerging model system for the study of physiology and metabolism, allow the temporal, spatial and high-throughput manipulation of putative intestinal sensors. Hence, fruit flies may prove particularly suited to the study of the link between intestinal nutrient sensing and metabolic homeostasis.

Miguel-Aliaga, Irene

2012-01-01

435

UPSTREAM-TO-DOWNSTREAM CHANGES IN NUTRIENT EXPORT RISK  

EPA Science Inventory

One of the early operating principles of landscape ecology was the importance of studying the movement of energy, nutrients, and biota in the horizontal or x,y plane (Risser et al. 1984). The new focus on horizontal movement was in part based on the recognition that many ecol...

436

Nutrient status: a missing factor in phenological and pollen research?  

PubMed Central

Phenology ranks among the best ecosystem processes for fingerprinting climate change since temperature explains a high percentage of the interannual or spatial variation in phenological onset dates. However, roles of other environmental variables, such as foliar nutrient concentrations, are far from adequately understood. This observational study examined the effects of air temperature and 11 nutrients on spring phenology of Betula pendula Roth (birch) along an urban–rural gradient in Munich, Germany, during the years 2010/2011. Moreover, the influence of temperature, nutrients, and air pollutants (NO2 and O3) on the amounts of pollen and catkin biomass in 2010 was evaluated. In addition to the influence of higher temperatures advancing phenological onset dates, higher foliar concentrations of potassium, boron, zinc, and calcium were statistically significantly linked to earlier onset dates. Since flushing of leaves is a turgor-driven process and all the influential nutrients are involved in cell extension, membrane function, and stability, there might be a reasonable physiological interpretation of the observed association. The amounts of pollen were negatively correlated with temperature, atmospheric NO2, and foliar iron concentration, suggesting that these variables restrict pollen production. The results of this study suggested an influence of nutritional status on both phenology and pollen production. The interaction of urbanization and climate change should be considered in the assessment of the impact of global warming on ecosystems and human health.

Jochner, Susanne

2013-01-01

437

Brain foods: the effects of nutrients on brain function  

Microsoft Academic Search

It has long been suspected that the relative abundance of specific nutrients can affect cognitive processes and emotions. Newly described influences of dietary factors on neuronal function and synaptic plasticity have revealed some of the vital mechanisms that are responsible for the action of diet on brain health and mental function. Several gut hormones that can enter the brain, or

Fernando Gómez-Pinilla

2008-01-01

438

DEVELOPMENT OF SAV LOSS-NUTRIENT LOAD RELATIONSHIPS  

EPA Science Inventory

The Nutrient Team effort related to SAV is comprised of two components. 1) collection of necessary data to determine the effectiveness of modeling SAV important to Gulf of Mexico estuarine environments; and 2) collaboration with the USGS wetland research center to analyze changes...

439

Thresholds of ecosystem response to nutrient enrichment from fish aggregations.  

PubMed

Biogeochemical hotspots can be driven by aggregations of animals, via excretion, that provide a concentrated source of limiting nutrients for primary producers. In a subtropical seagrass ecosystem, we characterized thresholds of ecological change associated with such hotspots surrounding artificial reef habitats. We deployed reefs of three sizes to aggregate fishes at different densities (and thus different levels of nutrient supply via excretion) and examined seagrass characteristics that reflect ecosystem processes. Responses varied as a function of reef size, with higher fish densities (on larger reefs) associated with more distinct ecological thresholds. For example, adjacent to larger reefs, the percentage of P content (%P) of seagrass (Thalassia testudinum) blades was significantly higher than background concentrations; fish densities on smaller reefs were insufficient to support sharp transitions in %P. Blade height was the only variable characterized by thresholds adjacent to smaller reefs, but lower fish densities (and hence, nutrient input) on smaller reefs were not sufficient for luxury nutrient storage by seagrass. Identifying such complexities in ecological thresholds is crucial for characterizing the extent to which biogeochemical hotspots may influence ecosystem function at a landscape scale. PMID:23691671

Layman, Craig A; Allgeier, Jacob E; Yeager, Lauren A; Stoner, Elizabeth W

2013-02-01

440

Ecosystem Modeling Applied to Nutrient Criteria Development in Rivers  

Microsoft Academic Search

Threshold concentrations for biological impairment by nutrients are difficult to quantify in lotic systems, yet States and Tribes in the United States are charged with developing water quality criteria to protect these ecosystems from excessive enrichment. The analysis described in this article explores the use of the ecosystem model AQUATOX to investigate impairment thresholds keyed to biological indexes that can

James N. Carleton; Richard A. Park; Jonathan S. Clough

2009-01-01

441

Nutrient factors affecting in vitro cultivation of Stevia rebaudiana  

Microsoft Academic Search

The present work was carried out to display in details the whole protocol for Stevia rebaudiana propagation through tissue culture techniques to produce and introduce Stevia rebaudiana plants as a new sweetener crop to Egyptian agriculture. In order to maximize plant propagation efficiently via direct organogenesis, it is important to study the influence of plant nutrient medium and its components

I. A. Ibrahim; M. I. Nasr; B. R. Mohammedm; M. M. El-Zefzafi

2008-01-01

442

Feasibility of nutrient recovery from industrial sludge by vermicomposting technology  

Microsoft Academic Search

Transformation of industrial sludges into vermicompost is of double interest: on the one hand, a waste is converted into value added product, and, on the other, it controls a pollutant that is a consequence of increasing industrialization. This paper reports the feasibility of utilization of vermicomposting technology for nutrient recovery from industrial sludge in laboratory scale experiment employing Eisenia fetida

Anoop Yadav; V. K. Garg

2009-01-01

443

Population dynamics and nutrient fluxes in an aquatic microcosm  

Microsoft Academic Search

An aquatic microcosm, consisting of three spatially separated yet mutually dependent trophic levels, was established in the laboratory and monitored for 310 days. A three-fold research approach evaluates the experimental potential of this large, multicompartmental microecosystem. Realistic biological and chemical features and nutrient fluxes parallel identifiable patterns observed in natural aquatic ecosystems as well as in published laboratory observations. Two

Catherine A. Elstad

1986-01-01

444

Growth Responses of Crop Plants to Fish Soluble Nutrients Fertilization.  

National Technical Information Service (NTIS)

The utilization of fish wastes in the form of fish soluble nutrients (FSN) for agricultural crop plants fertilization was investigated over the past 7 years as an aid to the Virginia seafood industry threatened by the waste disposal problem. Controlled gr...

L. H. Aung G. J. Flick G. R. Buss H. S. Aycock R. F. Keefer

1984-01-01

445

DISTURBED APPETITE PATTERNS AND NUTRIENT INTAKE IN PERITONEAL DIALYSIS PATIENTS  

Microsoft Academic Search

? ? ? ? ? Objective: Malnutrition is common among peritoneal dialysis (PD) patients. Reduced nutrient intake contrib- utes to this. It has long been assumed that this reflects disturbed appetite. We set out to define the appetite pro- files of a group of PD patients using a novel technique. ? ? ? ? ? Design: Prospective, cross-sectional comparison of

Mark Wright; Graham Woodrow; Siobahn O'Brien; Neil King; Louise Dye; John Blundell; Aleck Brownjohn; John Turney

446

Effect of nutrient enrichment on seagrass associated meiofauna in Tanzania.  

PubMed

Abundance, diversity and community structure of meiofauna, with special emphasis on epiphytic harpacticoid copepods, occurring in Tanzanian seagrass beds under various nutrient inputs was determined. All measured parameters for epiphytic meiofauna and diatoms (fucoxanthin) were negatively affected by nutrient input and this was detected even at the higher taxonomic levels of meiofauna, supporting the validity of higher taxon surrogacy in environmental impact studies. However, benthic meiofauna and other biofilm characteristics (chlorophyll a) did not show any difference between sites suggesting that nutrient enrichment had less impact on these variables. This indicates a differential impact of pollution on epiphytic vs. benthic communities. Consequently, different trophic levels will be impacted in various ways and hence the effects of pollution on the overall ecosystem functioning of seagrass beds are complex and not straightforward. Although the seagrass plants themselves don't show any major changes under different nutrient input, associated organisms that guarantee energy flow at basal levels of the food web in this ecosystem can be largely impacted. PMID:23072915

Daudi, Lillian Nduku; Lugomela, Charles; Uku, Jacqueline Nduku; De Troch, Marleen

2012-12-01

447

Recovery of three arctic stream reaches from experimental nutrient enrichment  

USGS Publications Warehouse

1. Nutrient enrichment and resulting eutrophication is a widespread anthropogenic influence on freshwater ecosystems, but recovery from nutrient enrichment is poorly understood, especially in stream environments. We examined multi-year patterns in community recovery from experimental low-concentration nutrient enrichment (N + P or P only) in three reaches of two Arctic tundra streams (Kuparuk River and Oksrukuyik Creek) on the North Slope of Alaska (U.S.A.). 2. Rates of recovery varied among community components and depended on duration of enrichment (2-13 consecutive growing seasons). Biomass of epilithic algae returned to reference levels rapidly (within 2 years), regardless of nutrients added or enrichment duration. Aquatic bryophyte cover, which increased greatly in the Kuparuk River only after long-term enrichment (8 years), took 8 years of recovery to approach reference levels, after storms had scoured most remnant moss in the recovering reach. 3. Multi-year persistence of bryophytes in the Kuparuk River appeared to prevent recovery of insect populations that had either been positively (e.g. the mayfly Ephemerella, most chironomid midge taxa) or negatively (e.g. the tube-building chironomid Orthocladius rivulorum) affected by this shift in dominant primary producer. These lags in recovery (of >3 years) were probably driven by the persistent effect of bryophytes on physical benthic habitat. 4. Summer growth rates of Arctic grayling (both adults and young-of-year) in Oksrukuyik Creek (fertilised for 6 years with no bryophyte colonisation), which were consistently increased by nutrient addition, returned to reference rates within 1-2 years. 5. Rates of recovery of these virtually pristine Arctic stream ecosystems from low-level nutrient enrichment appeared to be controlled largely by duration of enrichment, mediated through physical habitat shifts caused by eventual bryophyte colonisation, and subsequent physical disturbance that removed bryophytes. Nutrient enrichment of oligotrophic Arctic stream ecosystems caused by climate change or local anthropogenic activity may have dramatic and persistent consequences if it results in the colonisation of long-lived primary producers that alter physical habitat. ?? 2007 The Authors.

Benstead, J. P.; Green, A. C.; Deegan, L. A.; Peterson, B. J.; Slavik, K.; Bowden, W. B.; Hershey, A. E.

2007-01-01

448

Nutrient Presses and Pulses Differentially Impact Plants, Herbivores, Detritivores and Their Natural Enemies  

PubMed Central

Anthropogenic nutrient inputs into native ecosystems cause fluctuations in resources that normally limit plant growth, which has important consequences for associated food webs. Such inputs from agricultural and urban habitats into nearby natural systems are increasing globally and can be highly variable, spanning the range from sporadic to continuous. Despite the global increase in anthropogenically-derived nutrient inputs into native ecosystems, the consequences of variation in subsidy duration on native plants and their associated food webs are poorly known. Specifically, while some studies have examined the effects of nutrient subsidies on native ecosystems for a single year (a nutrient pulse), repeated introductions of nutrients across multiple years (a nutrient press) better reflect the persistent nature of anthropogenic nutrient enrichment. We therefore contrasted the effects of a one-year nutrient pulse with a four-year nutrient press on arthropod consumers in two salt marshes. Salt marshes represent an ideal system to address the differential impacts of nutrient pulses and presses on ecosystem and community dynamics because human development and other anthropogenic activities lead to recurrent introductions of nutrients into these natural systems. We found that plant biomass and %N as well as arthropod density fell after the nutrient pulse ended but remained elevated throughout the nutrient press. Notably, higher trophic levels responded more strongly than lower trophic levels to fertilization, and the predator/prey ratio increased each year of the nutrient press, demonstrating that food web responses to anthropogenic nutrient enrichment can take years to fully manifest themselves. Vegetation at the two marshes a