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Sample records for curvula schrad nees

  1. Nutritional and Sensory Evaluation of Injera Prepared from tef and Eragrostis curvula (Schrad.) Nees. Flours with Sorghum Blends

    PubMed Central

    Ghebrehiwot, Habteab M.; Shimelis, Hussein A.; Kirkman, Kevin P.; Laing, Mark D.; Mabhaudhi, Tafadzwanashe

    2016-01-01

    Injera is a fermented, sour bread consumed as a staple food in Eritrea and Ethiopia. The bread can be prepared from various cereals but tef [Eragrostis tef (Zucc.) Trotter] is the most preferred ingredient. This study assessed the acceptability of injera prepared using grains of a closely related but underutilized grass, Eragrostis curvula (Schrad.) Nees. The nutritive value of the grains was compared and the sensory attributes of injera made from flours of tef (control) and E. curvula, each combined with 0, 5, and 10% of sorghum flour, were assessed using a tasting panel. Nutrient analysis showed that E. curvula contains more than double the amount of crude protein found in tef. E. curvula also contains higher fat, dietary fiber and mineral nutrients than tef. Injera made of E. tef and E. curvula flours showed non-significant differences in taste, texture, appearance and overall acceptability. This suggest that E. curvula has the potential to serve as a novel source of gluten-free flour for human consumption. Agronomically viewed, growing E. curvula could be more advantageous for smallholder farmers on marginal lands because the species is a perennial that can produce a seed harvest twice a year, unlike tef, which is annual crop. It also tolerates acidic soils better than tef. PMID:27489554

  2. Nutritional and Sensory Evaluation of Injera Prepared from tef and Eragrostis curvula (Schrad.) Nees. Flours with Sorghum Blends.

    PubMed

    Ghebrehiwot, Habteab M; Shimelis, Hussein A; Kirkman, Kevin P; Laing, Mark D; Mabhaudhi, Tafadzwanashe

    2016-01-01

    Injera is a fermented, sour bread consumed as a staple food in Eritrea and Ethiopia. The bread can be prepared from various cereals but tef [Eragrostis tef (Zucc.) Trotter] is the most preferred ingredient. This study assessed the acceptability of injera prepared using grains of a closely related but underutilized grass, Eragrostis curvula (Schrad.) Nees. The nutritive value of the grains was compared and the sensory attributes of injera made from flours of tef (control) and E. curvula, each combined with 0, 5, and 10% of sorghum flour, were assessed using a tasting panel. Nutrient analysis showed that E. curvula contains more than double the amount of crude protein found in tef. E. curvula also contains higher fat, dietary fiber and mineral nutrients than tef. Injera made of E. tef and E. curvula flours showed non-significant differences in taste, texture, appearance and overall acceptability. This suggest that E. curvula has the potential to serve as a novel source of gluten-free flour for human consumption. Agronomically viewed, growing E. curvula could be more advantageous for smallholder farmers on marginal lands because the species is a perennial that can produce a seed harvest twice a year, unlike tef, which is annual crop. It also tolerates acidic soils better than tef.

  3. Apomixis frequency under stress conditions in weeping lovegrass (Eragrostis curvula)

    PubMed Central

    Rodrigo, Juan Manuel; Zappacosta, Diego Carlos; Selva, Juan Pablo; Garbus, Ingrid; Albertini, Emidio; Echenique, Viviana

    2017-01-01

    To overcome environmental stress, plants develop physiological responses that are triggered by genetic or epigenetic changes, some of which involve DNA methylation. It has been proposed that apomixis, the formation of asexual seeds without meiosis, occurs through the temporal or spatial deregulation of the sexual process mediated by genetic and epigenetic factors influenced by the environment. Here, we explored whether there was a link between the occurrence of apomixis and various factors that generate stress, including drought stress, in vitro culture, and intraspecific hybridization. For this purpose, we monitored the embryo sacs of different weeping lovegrass (Eragrostis curvula [Schrad.] Nees) genotypes after the plants were subjected to these stress conditions. Progeny tests based on molecular markers and genome methylation status were analyzed following the stress treatment. When grown in the greenhouse, the cultivar Tanganyika INTA generated less than 2% of its progeny by sexual reproduction. Plants of this cultivar subjected to different stresses showed an increase of sexual embryo sacs, demonstrating an increased expression of sexuality compared to control plants. Plants of the cv. Tanganyika USDA did not demonstrate the ability to generate sexual embryo sacs under any conditions and is therefore classified as a fully apomictic cultivar. We found that this change in the prevalence of sexuality was correlated with genetic and epigenetic changes analyzed by MSAP and AFLPs profiles. Our results demonstrate that different stress conditions can alter the expression of sexual reproduction in facultative tetraploid apomictic cultivars and when the stress stops the reproductive mode shift back to the apomixis original level. These data together with previous observations allow us to generate a hypothetical model of the regulation of apomixis in weeping lovegrass in which the genetic/s region/s that condition apomixis, is/are affected by ploidy, and is

  4. Apomixis frequency under stress conditions in weeping lovegrass (Eragrostis curvula).

    PubMed

    Rodrigo, Juan Manuel; Zappacosta, Diego Carlos; Selva, Juan Pablo; Garbus, Ingrid; Albertini, Emidio; Echenique, Viviana

    2017-01-01

    To overcome environmental stress, plants develop physiological responses that are triggered by genetic or epigenetic changes, some of which involve DNA methylation. It has been proposed that apomixis, the formation of asexual seeds without meiosis, occurs through the temporal or spatial deregulation of the sexual process mediated by genetic and epigenetic factors influenced by the environment. Here, we explored whether there was a link between the occurrence of apomixis and various factors that generate stress, including drought stress, in vitro culture, and intraspecific hybridization. For this purpose, we monitored the embryo sacs of different weeping lovegrass (Eragrostis curvula [Schrad.] Nees) genotypes after the plants were subjected to these stress conditions. Progeny tests based on molecular markers and genome methylation status were analyzed following the stress treatment. When grown in the greenhouse, the cultivar Tanganyika INTA generated less than 2% of its progeny by sexual reproduction. Plants of this cultivar subjected to different stresses showed an increase of sexual embryo sacs, demonstrating an increased expression of sexuality compared to control plants. Plants of the cv. Tanganyika USDA did not demonstrate the ability to generate sexual embryo sacs under any conditions and is therefore classified as a fully apomictic cultivar. We found that this change in the prevalence of sexuality was correlated with genetic and epigenetic changes analyzed by MSAP and AFLPs profiles. Our results demonstrate that different stress conditions can alter the expression of sexual reproduction in facultative tetraploid apomictic cultivars and when the stress stops the reproductive mode shift back to the apomixis original level. These data together with previous observations allow us to generate a hypothetical model of the regulation of apomixis in weeping lovegrass in which the genetic/s region/s that condition apomixis, is/are affected by ploidy, and is

  5. Expressed sequence tag analysis and development of gene associated markers in a near-isogenic plant system of Eragrostis curvula.

    PubMed

    Cervigni, Gerardo D L; Paniego, Norma; Díaz, Marina; Selva, Juan P; Zappacosta, Diego; Zanazzi, Darío; Landerreche, Iñaki; Martelotto, Luciano; Felitti, Silvina; Pessino, Silvina; Spangenberg, Germán; Echenique, Viviana

    2008-05-01

    Eragrostis curvula (Schrad.) Nees is a forage grass native to the semiarid regions of Southern Africa, which reproduces mainly by pseudogamous diplosporous apomixis. A collection of ESTs was generated from four cDNA libraries, three of them obtained from panicles of near-isogenic lines with different ploidy levels and reproductive modes, and one obtained from 12 days-old plant leaves. A total of 12,295 high-quality ESTs were clustered and assembled, rendering 8,864 unigenes, including 1,490 contigs and 7,394 singletons, with a genome coverage of 22%. A total of 7,029 (79.11%) unigenes were functionally categorized by BLASTX analysis against sequences deposited in public databases, but only 37.80% could be classified according to Gene Ontology. Sequence comparison against the cereals genes indexes (GI) revealed 50% significant hits. A total of 254 EST-SSRs were detected from 219 singletons and 35 from contigs. Di- and tri- motifs were similarly represented with percentages of 38.95 and 40.16%, respectively. In addition, 190 SNPs and Indels were detected in 18 contigs generated from 3 to 4 libraries. The ESTs and the molecular markers obtained in this study will provide valuable resources for a wide range of applications including gene identification, genetic mapping, cultivar identification, analysis of genetic diversity, phenotype mapping and marker assisted selection.

  6. [Study on chemical constituents of Citrullus vulgaris Schrad vine (II)].

    PubMed

    Gong, Xiao-Mei; Wang, Shuo; Zhou, Xiao-Lei; Zhou, Dan-Dan; Dai, Hang; Deng, Jia-Gang

    2013-10-01

    To study the chemical constituents of ethyl acetate fraction of Citrullus vulgaris Schrad vine. Compounds were isolated and purified by polyamide column chromatography, silica gel column chromatography, thin layer chromatography and sephadex gel column chromatography. Their structures were elucidated on the basis of physicochemical properties and spectral data. Ten compounds were isolated from Citrullus vulgaris Schrad vine and elucidated as: pentadecanoic acid (1), monopentadecanoin (2), 2, 3-dihydroxypropyl nonadecoate (3), lignoceric acid-2, 3-dihydroxy-propanenyl ester (4), lancerebroside 5 (5), salicylic acid (6), 4-hydroxybenzoic acid (7), hydroquinone (8), succinic acid (9) and vanillic acid (10). Compounds 1 - 10 are obtained from Citrullus vulgaris Schrad vine for the first time.

  7. Increased apomixis expression concurrent with genetic and epigenetic variation in a newly synthesized Eragrostis curvula polyploid

    PubMed Central

    Zappacosta, Diego C.; Ochogavía, Ana C.; Rodrigo, Juan M.; Romero, José R.; Meier, Mauro S.; Garbus, Ingrid; Pessino, Silvina C.; Echenique, Viviana C.

    2014-01-01

    Eragrostis curvula includes biotypes reproducing through obligate and facultative apomixis or, rarely, full sexuality. We previously generated a “tetraploid-dihaploid-tetraploid” series of plants consisting of a tetraploid apomictic plant (T), a sexual dihaploid plant (D) and a tetraploid artificial colchiploid (C). Initially, plant C was nearly 100% sexual. However, its capacity to form non-reduced embryo sacs dramatically increased over a four year period (2003–2007) to reach levels of 85–90%. Here, we confirmed high rates of apomixis in plant C, and used AFLPs and MSAPs to characterize the genetic and epigenetic variation observed in this plant in 2007 as compared to 2003. Of the polymorphic sequences, some had no coding potential whereas others were homologous to retrotransposons and/or protein-coding-like sequences. Our results suggest that in this particular plant system increased apomixis expression is concurrent with genetic and epigenetic modifications, possibly involving transposable elements. PMID:24710346

  8. Increased apomixis expression concurrent with genetic and epigenetic variation in a newly synthesized Eragrostis curvula polyploid

    NASA Astrophysics Data System (ADS)

    Zappacosta, Diego C.; Ochogavía, Ana C.; Rodrigo, Juan M.; Romero, José R.; Meier, Mauro S.; Garbus, Ingrid; Pessino, Silvina C.; Echenique, Viviana C.

    2014-04-01

    Eragrostis curvula includes biotypes reproducing through obligate and facultative apomixis or, rarely, full sexuality. We previously generated a ``tetraploid-dihaploid-tetraploid'' series of plants consisting of a tetraploid apomictic plant (T), a sexual dihaploid plant (D) and a tetraploid artificial colchiploid (C). Initially, plant C was nearly 100% sexual. However, its capacity to form non-reduced embryo sacs dramatically increased over a four year period (2003-2007) to reach levels of 85-90%. Here, we confirmed high rates of apomixis in plant C, and used AFLPs and MSAPs to characterize the genetic and epigenetic variation observed in this plant in 2007 as compared to 2003. Of the polymorphic sequences, some had no coding potential whereas others were homologous to retrotransposons and/or protein-coding-like sequences. Our results suggest that in this particular plant system increased apomixis expression is concurrent with genetic and epigenetic modifications, possibly involving transposable elements.

  9. Increased apomixis expression concurrent with genetic and epigenetic variation in a newly synthesized Eragrostis curvula polyploid.

    PubMed

    Zappacosta, Diego C; Ochogavía, Ana C; Rodrigo, Juan M; Romero, José R; Meier, Mauro S; Garbus, Ingrid; Pessino, Silvina C; Echenique, Viviana C

    2014-04-08

    Eragrostis curvula includes biotypes reproducing through obligate and facultative apomixis or, rarely, full sexuality. We previously generated a "tetraploid-dihaploid-tetraploid" series of plants consisting of a tetraploid apomictic plant (T), a sexual dihaploid plant (D) and a tetraploid artificial colchiploid (C). Initially, plant C was nearly 100% sexual. However, its capacity to form non-reduced embryo sacs dramatically increased over a four year period (2003-2007) to reach levels of 85-90%. Here, we confirmed high rates of apomixis in plant C, and used AFLPs and MSAPs to characterize the genetic and epigenetic variation observed in this plant in 2007 as compared to 2003. Of the polymorphic sequences, some had no coding potential whereas others were homologous to retrotransposons and/or protein-coding-like sequences. Our results suggest that in this particular plant system increased apomixis expression is concurrent with genetic and epigenetic modifications, possibly involving transposable elements.

  10. Antibacterial and anticandidal screening of Tunisian Citrullus colocynthis Schrad. from Medenine.

    PubMed

    Marzouk, Belsem; Marzouk, Zohra; Décor, Rachel; Edziri, Hayet; Haloui, Ehsen; Fenina, Nadia; Aouni, Mahjoub

    2009-09-07

    Resistance to current antibacterial drugs and the rise of opportunistic fungal infections are growing global concerns. Traditional medicine is a potential source of new antibacterials and antifungals. Citrullus colocynthis Schrad. (Cucurbitaceae) endemic in Southern Tunisia, is used in folk medicine against dermatological, gynaecological and pulmonary infections. To assess in vitro antibacterial and anticandidal activity of aqueous and diluted acetone extracts of Citrullus colocynthis Schrad. MIC and MBC/MFC were determined for plant organs at different maturation stages. Citrullus colocynthis Schrad. was harvested and its identification was verified. Aqueous and diluted acetone extracts (from the plant's roots, stems, leaves and three maturation stages of its fruit and seeds) were screened for activity against Gram-negative and Gram-positive bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis)-and various Candida spp. (Candida glabrata, Candida albicans, Candida parapsilosis and Candida kreusei). All extracts showed activity against all strains. The highest MICs and MBCs/MFCs were obtained from the fruit aqueous extracts (MIC 0.10mg/ml against Candida albicans and Candida glabrata, 0.20mg/ml against Escherichia coli and Pseudomonas aeruginosa), lowest activity from the root extracts. Citrullus colocynthis Schrad. shows antibacterial and anticandidal properties. The folk medicinal use as a broad-spectrum antimicrobial agent is validated.

  11. Ecological characterisation of supina bluegrass (Poa supina Schrad.) germplasm from the Italian Alps

    USDA-ARS?s Scientific Manuscript database

    Supina bluegrass (Poa supina Schrad.) is a potential turfgrass species for cool, northern type climates, yet few genetic resources for research and development are very limited. As a result, a field exploration for P. supina was conduction in the Italian Alps in 2008. Altogether, 55 populations of...

  12. Genetic introgression as a potential to widen a species' niche: insights from alpine Carex curvula.

    PubMed

    Choler, P; Erschbamer, B; Tribsch, A; Gielly, L; Taberlet, P

    2004-01-06

    Understanding what causes the decreasing abundance of species at the margins of their distributions along environmental gradients has drawn considerable interest, especially because of the recent need to predict shifts in species distribution patterns in response to climatic changes. Here, we address the ecological range limit problem by focusing on the sedge, Carex curvula, a dominant plant of high-elevation grasslands in Europe, for which two ecologically differentiated but crosscompatible taxa have been described in the Alps. Our study heuristically combines an extensive phytoecological survey of alpine plant communities to set the niche attributes of each taxon and a population genetic study to assess the multilocus genotypes of 177 individuals sampled in typical and marginal habitats. We found that ecological variation strongly correlates with genetic differentiation. Our data strongly suggest that ecologically marginal populations of each taxon are mainly composed of individuals with genotypes resulting from introgressive hybridization. Conversely, no hybrids were found in typical habitats, even though the two taxa were close enough to crossbreed. Thus, our results indicate that genotype integrity is maintained in optimal habitats, whereas introgressed individuals are favored in marginal habitats. We conclude that gene flow between closely related taxa might be an important, although underestimated, mechanism shaping species distribution along gradients.

  13. Development of plant regeneration and transformation protocols for the desiccation-sensitive weeping lovegrass Eragrostis curvula.

    PubMed

    Ncanana, Sandile; Brandt, Wolf; Lindsey, George; Farrant, Jill

    2005-08-01

    A tissue culture protocol, suitable for transformation, was established for the pasture grass Eragrostis curvula. Callus was generated in the dark from leaf and seed tissues on a medium comprising MS salts supplemented with 2 mg/l 2,4-D, 0.01 mg/l BAP and 2% sucrose. Plant regeneration occurred via organogenesis on the same medium with 6% and 3% sucrose for shoot and root formation, respectively. Optimal regeneration (50 plantlets per callus) occurred when light of 45 micromol/m2 per s was used. The yeast Saccharomyces cerevisiae Hsp12 gene was cloned into the Sac1 of the pCAMBIAUbeeQ vector and callus was transformed by biolistic bombardment. Best transformation (30%) occurred when the target tissue was bombarded twice at a distance of 70 mm using a bombardment pressure of 9,100 kPa. Although successful transformation and transcription of the Hsp12 gene occurred, no Hsp12 protein was found present in tissue extracts of transformed grass.

  14. Variation in cytosine methylation patterns during ploidy level conversions in Eragrostis curvula.

    PubMed

    Ochogavía, Ana C; Cervigni, Gerardo; Selva, Juan P; Echenique, Viviana C; Pessino, Silvina C

    2009-05-01

    In many species polyploidization involves rearrangements of the progenitor genomes, at both genetic and epigenetic levels. We analyzed the cytosine methylation status in a 'tetraploid-diploid-tetraploid' series of Eragrostis curvula with a common genetic background by using the MSAP (Methylation-sensitive Amplified Polymorphism) technique. Considerable levels of polymorphisms were detected during ploidy conversions. The total level of methylation observed was lower in the diploid genotype compared to the tetraploid ones. A significant proportion of the epigenetic modifications occurring during the tetraploid-diploid conversion reverted during the diploid-tetraploid one. Genetic and expression data from previous work were used to analyze correlation with methylation variation. All genetic, epigenetic and gene expression variation data correlated significantly when compared by pairs in simple Mantel tests. Dendrograms reflecting genetic, epigenetic and expression distances as well as principal coordinate analysis suggested that plants of identical ploidy levels present similar sets of data. Twelve (12) different genomic fragments displaying different methylation behavior during the ploidy conversions were isolated, sequenced and characterized.

  15. Gene expression in diplosporous and sexual Eragrostis curvula genotypes with differing ploidy levels.

    PubMed

    Cervigni, Gerardo D L; Paniego, Norma; Pessino, Silvina; Selva, Juan P; Díaz, Marina; Spangenberg, Germán; Echenique, Viviana

    2008-05-01

    The molecular nature of gene expression during the initiation and progress of diplosporous apomixis is still unknown. Moreover, the basis of the close correlation between diplospory and polyploidy is not clarified yet. A comparative expression analysis was performed based on expressed sequence tags (ESTs) sequencing and differential display in an Eragrostis curvula diplosporous tetraploid genotype (T, 4x apo), a sexual diploid derivative obtained from tissue culture (D, 2x sex) and an artificial sexual tetraploid obtained from the diploid seeds after colchicine treatment (C, 4x sex). From a total of 8,884 unigenes sequenced from inflorescence-derived libraries, 112 (1.26%) showed significant differential expression in individuals with different ploidy level and/or variable reproductive mode. Independent comparisons between plants with different reproductive mode (same ploidy) or different ploidy level (same reproductive mode) allowed the identification of genes modulated in response to diplosporous development or polyploidization, respectively. Surprisingly, a group of genes (Group 3) were differentially expressed or silenced only in the 4x sex plant, presenting similar levels of expression in the 4x apo and the 2x sex genotypes. A group of randomly selected differential genes was validated by QR-PCR. Differential display analysis showed that in general the 4x apo and 4x sex expression profiles were more related and different from the 2x sex one, but confirmed the existence of Group 3-type genes, in both inflorescences and leaves. The possible biological significance for the occurrence of this particular group of genes is discussed. In silico mapping onto the rice genome was used to identify candidates mapping to the region syntenic to the diplospory locus.

  16. Constituents of leaves from Bauhinia curvula Benth. exert gastroprotective activity in rodents: role of quercitrin and kaempferol.

    PubMed

    Beber, Ana Paula; de Souza, Priscila; Boeing, Thaise; Somensi, Lincon Bordignon; Mariano, Luísa Nathália Bolda; Cury, Benhur Judah; Burci, Ligia Moura; da Silva, Cristiane Bezerra; Simionatto, Euclésio; de Andrade, Sérgio Faloni; da Silva, Luísa Mota

    2017-02-07

    The Bauhinia genus is known as "Pata-de-Vaca" and a wide variety of these species are used in Brazilian folk medicine due to their gastroprotective properties. This study aimed to investigate the antiulcer efficacy of the hydroalcoholic extract from B. curvula (HEBC) leaves, as well as its semi-purified fraction (SPFr) and the contribution of their phytochemicals constituents for this effect. For that, ethanol 60%/HCl 0.3 M- and indomethacin-induced gastric ulcer were performed in rodents. Gastric ulcerated tissues were processed for histological, histochemical and biochemical analysis. The oral treatment with HEBC and SPFr decreased the gastric ulcer induced by ethanol/HCl in mice and by indomethacin (only HEBC) in rats. The gastroprotective effect of HEBC was abolished in mice pretreated with Nω-Nitro-L-arginine methyl ester, N-Ethylmaleimide, glibenclamide or indomethacin. Both HEBC and SPFr reduced myeloperoxidase activity in parallel with a decrease of lipoperoxides content at the site of the lesion. On the other hand, HEBC did not alter volume, pH, total acidity or pepsin activity of acid gastric secretion in rats, and neither inhibited the in vitro H(+),K(+)-ATPase activity. Additionally, the compounds identified and isolated from the SPFr, the flavonoids quercitrin (65%) and kaempferol (35%), were able to diminish the extent of ulcerated area induced by both ethanol/HCl and indomethacin. Taking together, these findings show that B. curvula extracts present gastroprotective effect, mainly explained by the presence of flavonoids quercitrin and kaempferol, which may possibly improve the defensive factors of gastric mucosa.

  17. NeeMDB: Convenient Database for Neem Secondary Metabolites

    PubMed Central

    Hatti, Kaushik S; Muralitharan, Lakshmi; Hegde, Rajendra; Kush, Anil

    2014-01-01

    Indian Neem tree is known for its pesticidal and medicinal properties for centuries. Structure elucidation of large number of secondary metabolites responsible for its diverse properties has been achieved. However, this data is spread over various books, scientific reports and publications and difficult to access. We have compiled and stored structural details of neem metabolites in NeeMDB, a database which can be easily accessed, queried and downloaded. NeeMDB would be central in dissipating structural information of neem secondary metabolites world over. PMID:24966540

  18. NeeMDB: Convenient Database for Neem Secondary Metabolites.

    PubMed

    Hatti, Kaushik S; Muralitharan, Lakshmi; Hegde, Rajendra; Kush, Anil

    2014-01-01

    Indian Neem tree is known for its pesticidal and medicinal properties for centuries. Structure elucidation of large number of secondary metabolites responsible for its diverse properties has been achieved. However, this data is spread over various books, scientific reports and publications and difficult to access. We have compiled and stored structural details of neem metabolites in NeeMDB, a database which can be easily accessed, queried and downloaded. NeeMDB would be central in dissipating structural information of neem secondary metabolites world over.

  19. A review on Citrullus colocynthis Schrad.: from traditional Iranian medicine to modern phytotherapy.

    PubMed

    Rahimi, Roja; Amin, Gholamreza; Ardekani, Mohammad Reza Shams

    2012-06-01

    Citrullus colocynthis Schrad. is an annual plant that grows in the south, center, and east areas of Iran. It is recognized by different pharmacologic activities in traditional Iranian medicine (TIM) (i.e., purgative, anti-inflammatory, antidiabetic, analgesic, hair growth-promoting, abortifacient, and antiepileptic. Some of these activities were confirmed in modern phytotherapy. Adverse events such as colic, diarrhea, hematochezia, nephrosis, and vomiting and narrow therapeutic index cause herbalists to use this plant cautiously. If some points about this plant in TIM are considered, it may be possible to produce more tolerable preparations from this plant. In this article, all aspects of this plant in TIM are reviewed; also, the medicinal properties declared for this plant in TIM are compared with those showed in modern phytotherapy. In addition, opinions of TIM and modern phytotherapy about safety and acceptable dosage of this plant are discussed.

  20. Antioxidant and free radical scavenging potential of Citrullus colocynthis (L.) Schrad. methanolic fruit extract.

    PubMed

    Kumar, Sunil; Kumar, Dinesh; Manjusha; Saroha, Kamal; Singh, Nidhan; Vashishta, Bhoodev

    2008-06-01

    Citrullus colocynthis (L.) Schrad. (Cucurbitaceae) is a medicinal plant traditionally used as an abortifacient and to treat constipation, oedema, bacterial infections, cancer and diabetes. Preliminary phytochemical screening of the plant showed the presence of large amounts of phenolics and flavonoids. Subsequent quantification showed the presence of 0.74% (m/m) phenolics (calculated as gallic acid) and 0.13% (m/m) flavonoids calculated as catechin equivalents per 100 g of fresh mass. The presence of phenolic compounds prompted us to evaluate its antioxidant activity. In the present study, methanolic fruit extract of C. colocynthis was screened to evaluate its free radical scavenging effect. The highest antioxidant and free radical scavenging ability of the fruit extract was observed at a concentration of 2500 microg mL(-1).

  1. Effect of Citrullus colocynthis Schrad fruits on testosterone-induced alopecia.

    PubMed

    Dhanotia, Renuka; Chauhan, Nagendra Singh; Saraf, Dinesh K; Dixit, Vinod K

    2011-09-01

    Alopecia is a psychologically distressing phenomenon. Androgenetic alopecia (AGA) is the most common form of alopecia, which affects millions of men and women worldwide, and is an androgen driven disorder. Here, the Citrullus colocynthis Schrad fruit is evaluated for hair growth activity in androgen-induced alopecia. Petroleum ether extract of C. colocynthis was applied topically for its hair growth-promoting activity. Alopecia was induced in albino mice by testosterone administration intramuscularly for 21 days. Its inhibition by simultaneous administration of extract was evaluated using follicular density, anagen/telogen (A/T) ratio and microscopic observation of skin sections. Finasteride (5α-reductase inhibitor) solution was applied topically and served as positive control. Petroleum ether extract of C. colocynthis exhibited promising hair growth-promoting activity, as reflected from follicular density, A/T ratio and skin sections. The treatment was also successful in bringing a greater number of hair follicles in anagenic phase than the standard finasteride. The result of treatment with 2 and 5% petroleum ether extracts were comparable to the positive control finasteride. The petroleum ether extract of C. colocynthis and its isolate is useful in the treatment of androgen-induced alopecia.

  2. Mosquito larvicidal activity of oleic and linoleic acids isolated from Citrullus colocynthis (Linn.) Schrad.

    PubMed

    Rahuman, A Abdul; Venkatesan, P; Gopalakrishnan, Geetha

    2008-11-01

    In mosquito control programs, botanical origin may have the potential to be used successfully as larvicides. The larvicidal activity of crude acetone, hexane, ethyl acetate, methanol, and petroleum ether extracts of the leaf of Centella asiatica Linn., Datura metal Linn., Mukia scabrella Arn., Toddalia asiatica (Linn.) Lam, extracts of whole plant of Citrullus colocynthis (Linn.) Schrad, and Sphaeranthus indicus Linn. were assayed for their toxicity against the early fourth instar larvae of Culex quinquefasciatus (Diptera: Culicidae). The larval mortality was observed after 24 h exposure. All extracts showed moderate larvicidal effects; however, the highest larval mortality was found in whole plant petroleum ether extract of C. colocynthis. In the present study, bioassay-guided fractionation of petroleum ether extract led to the separation and identification of fatty acids; oleic acid and linoleic acid were isolated and identified as mosquito larvicidal compounds. Oleic and Linoleic acids were quite potent against fourth instar larvae of Aedes aegypti L. (LC50 8.80, 18.20 and LC90 35.39, 96.33 ppm), Anopheles stephensi Liston (LC50 9.79, 11.49 and LC90 37.42, 47.35 ppm), and Culex quinquefasciatus Say (LC50 7.66, 27.24 and LC90 30.71, 70.38 ppm). The structure was elucidated from infrared, ultraviolet, 1H-nuclear magnetic resonance, 13C-NMR, and mass spectral data. This is the first report on the mosquito larvicidal activity of the reported isolated compounds from C. colocynthis.

  3. Anti-inflammatory and analgesic activities of Tunisian Citrullus colocynthis Schrad. immature fruit and seed organic extracts.

    PubMed

    Marzouk, B; Marzouk, Z; Fenina, N; Bouraoui, A; Aouni, M

    2011-06-01

    Inflammations and immune-related diseases including rheumatoid arthritis are widespread in the entire globe. The treatment of these illnesses is mainly based on the use of synthetic and biotechnological drugs, in recent years. Tunisian traditional medicine is a potential source of new remedies namely Citrullus colocynthis Schrad. (Cucurbitaceae): endemic in southern Tunisia and used in folk medicine to treat many inflammation disorders. Our goal was to assess the in vivo analgesic and anti-inflammatory activities of Tunisian Citrullus colocynthis immature fruit and seed organic extracts (petroleum ether, chloroform, ethyl acetate, acetone and finely methanol extract). Yields of prepared organic extracts are gravimetrically determined. For the analgesic and anti-inflammatory activities, we have used respectively, the acetic acid writhing test in mice and the carrageenan-induced paw edema assay in rats. All extracts displayed an important analgesic and anti-inflammatory activities at different doses without inducing any side effects. This study has demonstrated the analgesic and anti-inflammatory activities of Citrullus colocynthis immature fruit and seed extracts. Experiment results provide scientific insight into the ancient practice of utilizing Citrullus colocynthis Schrad. as analgesic and as anti-inflammatory agents.

  4. Erythropoietic activity of Asteracantha longifolia (Nees.) in rats.

    PubMed

    Pawar, Rajesh Singh; Jain, Alok Pal; Lodhi, Santram; Singhai, Abhay K

    2010-05-27

    Asteracantha longifolia Nees. (Family-Acanthaceae) is a wild herb commonly used in traditional ayurvedic medicine as Kokilaaksha and the Unani drug as Talimakhana in India and Srilanka for various medicinal uses as aphrodisiac, tonic, sedative and blood diseases etc. The aim of the current study was to validate and explore the folk use of Asteracantha longifolia Nees. (AL) (Leaf part) on pharmacological grounds using haloperidol induced iron deficiency anemia for the assessment of erythropoietic activity. Determination of iron in plant extracts was carried out using spectrophotometric method. Plant extract was obtained from crude drugs using extraction with ethanol. In vivo study, haloperidol induced iron deficiency anemia model was used in experimental studies. An administration of ethanolic extract of AL at the doses of 100 mg/kg and 200 mg/kg body weight, i.p., demonstrated a significant (P<0.05) increase in erythrocyte count, haemoglobin count, serum iron and serum protein etc. This effect may be due to the presence of iron (622 microg/50 mg) in extract estimated by spectrophotometric method. An ethanolic extract of AL effectively restored the hematological parameters, serum iron and serum protein and normalized the microcytic (smaller in size), anisocytosis (disturbed shape) and hypochromic RBCs. These observations could justify the inclusion of this plant in the management of iron deficiency anemia due the presence of iron and other constituents as flavonoids, terpenoids, steroids, lupeol and betulin. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

  5. Variation of NEE and its affecting factors in a vineyard of arid region of northwest China

    NASA Astrophysics Data System (ADS)

    Guo, W. H.; Kang, S. Z.; Li, F. S.; Li, S. E.

    2014-02-01

    To understand the variation of net ecosystem CO2 exchange (NEE) in orchard ecosystem and it's affecting factors, carbon flux was measured using eddy covariance system in a wine vineyard in arid northwest China during 2008-2010. Results show that vineyard NEE was positive value at the early growth stage, higher negative value at the mid-growth stage, and lower negative value at the later growth stage. Diurnal variation of NEE was "W" shaped curve in sunny day, but "U" shaped curve in cloudy day. Irrigation and pruning did not affect diurnal variation shape of NEE, however, irrigation reduced the difference between maximal and minimal value of NEE and pruning reduced the carbon sink capacity. The main factors affecting hourly NEE were canopy conductance (gc) and net radiation (Rn). The hourly NEE increased with the increase of gc or Rn when gc was less than 0.02 m·s-1 or Rn was between 0 and 200 W·m-2. The main factors affecting both daily and seasonal NEE were gc, air temperature (Ta), atmospheric CO2 density, vapour pressure deficit (VPD) and soil moisture content.

  6. Genome polymorphisms and gene differential expression in a 'back-and-forth' ploidy-altered series of weeping lovegrass (Eragrostis curvula).

    PubMed

    Mecchia, Martín A; Ochogavía, Ana; Pablo Selva, Juan; Laspina, Natalia; Felitti, Silvina; Martelotto, Luciano G; Spangenberg, Germán; Echenique, Viviana; Pessino, Silvina C

    2007-08-01

    Molecular markers were used to analyze the genomic structure of an euploid series of Eragrostis curvula, obtained after a tetraploid dihaploidization procedure followed by chromosome re-doubling with colchicine. Considerable levels of genome polymorphisms were detected between lines. Curiously, a significant number of molecular markers showed a revertant behavior following the successive changes of ploidy, suggesting that genome alterations were specific and conferred genetic structures characteristic of a given ploidy level. Genuine reversion was confirmed by sequencing. Cluster analysis demonstrated grouping of tetraploids while the diploid was more distantly related with respect to the rest of the plants. Polymorphic revertant sequences involved mostly non-coding regions, although some of them displayed sequence homology to known genes. A revertant sequence corresponding to a P-type adenosine triphosphatase was found to be differentially represented in cDNA libraries obtained from the diploid and a colchiploid, but was not found expressed in the original tetraploid. Transcriptome profiling of inflorescence followed by real-time polymerase chain reaction validation showed 0.34% polymorphic bands between apomictic tetraploid and sexual diploid plants. Several of the polymorphic sequences corresponded to known genes. Possible correlation between the results observed here and a recently reported genome-wide non-Mendelian inheritance mechanism in Arabidopsis thaliana are discussed.

  7. Inhibitory effect on α-glucosidase by Adhatoda vasica Nees.

    PubMed

    Gao, Hong; Huang, Yi-Na; Gao, Bo; Li, Peng; Inagaki, Chika; Kawabata, Jun

    2008-06-01

    Methanolic extracts from the medicinal parts of 40 traditional Chinese herbs were tested in screening experiments for rat intestinal α-glucosidase. The methanolic extract from the leaves of Adhatoda vasica Nees (Acanthaceae) showed the highest sucrase inhibitory activity with sucrose as a substrate. Enzyme assay-guided fractionation of this extract afforded vasicine (1) and vasicinol (2), and the structures of these compounds were elucidated on the basis of MS and NMR analysis. Compounds 1 and 2 showed a high sucrase inhibitory activity, and the IC50 values were 125μM and 250μM, respectively. Both 1 and 2 were shown to be reversible inhibitors of sucrase. Kinetic data revealed that compounds 1 and 2 inhibited sucrose-hydrolysing activity of rat intestinal α-glucosidase competitively with Ki values of 82μM and 183μM, respectively. This is the first report on the mammalian α-glucosidase inhibition of A. vasica and the inhibitory effect on sucrase by 1 and 2 from this herb species. These results suggest a use of the extract of A. vasica as an antidiabetic agent and show a possibility that compounds 1 and 2 could be an useful treatment for metabolic disorders. Copyright © 2007 Elsevier Ltd. All rights reserved.

  8. Evaluation and characterisation of Citrullus colocynthis (L.) Schrad seed oil: Comparison with Helianthus annuus (sunflower) seed oil.

    PubMed

    Nehdi, Imededdine Arbi; Sbihi, Hassen; Tan, Chin Ping; Al-Resayes, Saud Ibrahim

    2013-01-15

    The physicochemical properties, fatty acid, tocopherol, thermal properties, (1)H NMR, FTIR and profiles of non-conventional oil extracted from Citrullus colocynthis (L.) Schrad seeds were evaluated and compared with conventional sunflower seed oil. In addition, the antioxidant properties of C. colocynthis seed oil were also evaluated. The oil content of the C. colocynthis seeds was 23.16%. The main fatty acids in the oil were linoleic acid (66.73%) followed by oleic acid (14.78%), palmitic acid (9.74%), and stearic acid (7.37%). The tocopherol content was 121.85 mg/100g with γ-tocopherol as the major one (95.49%). The thermogravimetric analysis showed that the oil was thermally stable up to 286.57°C, and then began to decompose in four stages namely at 377.4°C, 408.4°C, 434.9°C and 559.2°C. The present study showed that this non-conventional C. colocynthis seed oil can be used for food and non-food applications to supplement or replace some of the conventional oils. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Central Nervous System Effects of Iso-6-spectaline Isolated from Senna Spectabilis var. Excelsa (Schrad) in Mice.

    PubMed

    Silva, Fo; Silva, Mgv; Cerqueira, Gs; Sabino, Eb; Almeida, Aac; Costa, Jp; Freitas, Rm

    2011-07-01

    The central nervous system (CNS) depressant and anticonvulsant activities of iso-6-spectaline (SPEC) were investigated in animal models. The SPEC from Senna spectabilis var. excelsa (Schrad) (0.1, 0.5 and 1.0 mg/ kg) injected by oral route (p.o.) in mice caused a significant decrease in the motor activity up to 30 days after the administration and in the dose of 1.0 mg/kg significantly reduced the remaining time on the Rota-rod apparatus. Additionally, SPEC (0.1, 0.5 and 1.0 mg/kg, p.o.) was also capable of promoting increase of latency for development of convulsions induced by pentylenetetrazole. This SPEC was also capable of promoting an increase of latency for development of convulsions induced by picrotoxin at highest dose. In the same way, the anticonvulsant effect of SPEC was affected by pretreatment with flumazenil, a selective antagonist of the benzodiazepine site of the GABA(A) receptor. These results suggest possible CNS depressant and anticonvulsant activities in mice that needs further investigation.

  10. Central Nervous System Effects of Iso-6-spectaline Isolated from Senna Spectabilis var. Excelsa (Schrad) in Mice

    PubMed Central

    Silva, FO; Silva, MGV; Cerqueira, GS; Sabino, EB; Almeida, AAC; Costa, JP; Freitas, RM

    2011-01-01

    The central nervous system (CNS) depressant and anticonvulsant activities of iso-6-spectaline (SPEC) were investigated in animal models. The SPEC from Senna spectabilis var. excelsa (Schrad) (0.1, 0.5 and 1.0 mg/ kg) injected by oral route (p.o.) in mice caused a significant decrease in the motor activity up to 30 days after the administration and in the dose of 1.0 mg/kg significantly reduced the remaining time on the Rota-rod apparatus. Additionally, SPEC (0.1, 0.5 and 1.0 mg/kg, p.o.) was also capable of promoting increase of latency for development of convulsions induced by pentylenetetrazole. This SPEC was also capable of promoting an increase of latency for development of convulsions induced by picrotoxin at highest dose. In the same way, the anticonvulsant effect of SPEC was affected by pretreatment with flumazenil, a selective antagonist of the benzodiazepine site of the GABAA receptor. These results suggest possible CNS depressant and anticonvulsant activities in mice that needs further investigation. PMID:21897664

  11. Green Microwave-Assisted Combustion Synthesis of Zinc Oxide Nanoparticles with Citrullus colocynthis (L.) Schrad: Characterization and Biomedical Applications.

    PubMed

    Azizi, Susan; Mohamad, Rosfarizan; Mahdavi Shahri, Mahnaz

    2017-02-16

    In this paper, a green microwave-assisted combustion approach to synthesize ZnO-NPs using zinc nitrate and Citrullus colocynthis (L.) Schrad (fruit, seed and pulp) extracts as bio-fuels is reported. The structure, optical, and colloidal properties of the synthesized ZnO-NP samples were studied. Results illustrate that the morphology and particle size of the ZnO samples are different and depend on the bio-fuel. The XRD results revealed that hexagonal wurtzite ZnO-NPs with mean particle size of 27-85 nm were produced by different bio-fuels. The optical band gap was increased from 3.25 to 3.40 eV with the decreasing of particle size. FTIR results showed some differences in the surface structures of the as-synthesized ZnO-NP samples. This led to differences in the zeta potential, hydrodynamic size, and more significantly, antioxidant activity through scavenging of 1, 1-Diphenyl-2-picrylhydrazyl (DPPH) free radicals. In in vitro cytotoxicity studies on 3T3 cells, a dose dependent toxicity with non-toxic effect of concentration below 0.26 mg/mL was shown for ZnO-NP samples. Furthermore, the as-synthesized ZnO-NPs inhibited the growth of medically significant pathogenic gram-positive (Bacillus subtilis and Methicillin-resistant Staphylococcus aurous) and gram-negative (Peseudomonas aeruginosa and Escherichia coli) bacteria. This study provides a simple, green and efficient approach to produce ZnO nanoparticles for various applications.

  12. Citrullus colocynthis (L.) Schrad (bitter apple fruit): a review of its phytochemistry, pharmacology, traditional uses and nutritional potential.

    PubMed

    Hussain, Abdullah I; Rathore, Hassaan A; Sattar, Munavvar Z A; Chatha, Shahzad A S; Sarker, Satyajit D; Gilani, Anwar H

    2014-08-08

    Citrullus colocynthis (L.) Schrad is a valuable cucurbit plant, widely distributed in the desert areas of the world. Citrullus colocynthis fruits are usually recognized for its wide range of medicinal uses as well as pharmaceutical and nutraceutical potential. This review aims to appraise the published information on the ethnobotanical knowledge, phytochemistry, ethnopharmacology, nutraceutical potential and safety studies of Citrullus colocynthis (bitter apple) fruit, with critical analysis on the gaps and potential for future studies. A literature survey was performed by searching the scientific databases including PubMed, Scopus, SciFinder, Google Scholar, Web of Science, ACS as well as published books. The plant has been reported to possess a wide range of traditional medicinal uses including in diabetes, leprosy, common cold, cough, asthma, bronchitis, jaundice, joint pain, cancer, toothache, wound, mastitis, and in gastrointestinal disorders such as indigestion, constipation, dysentery, gastroenteritis, colic pain and different microbial infections. Several bioactive chemical constituents from fruits were recorded, such as, glycosides, flavonoids, alkaloids, fatty acids and essential oils. The isolation and identification of curcurbitacins A, B, C, D, E, I, J, K, and L and Colocynthosides A, and B were also reported. The fruit of Citrullus colocynthis has been studied extensively for its wide range of biological activities, which include antioxidant, cytotoxic, antidiabetic, antilipidemic, insecticide, antimicrobial and anti-inflammatory. The plant was also shown to be rich in nutritional value with high protein contents and important minerals as well as edible quality of seed oil. It is evident from the literature that Citrullus colocynthis possesses a wide range of medicinal uses and has been well studied for its antidiabetic, anticancer, antioxidant, antimicrobial and anti-inflammatory activities, while its therapeutic potential for gut, airways and

  13. New neolignans and lignans from Vietnamese medicinal plant Machilus odoratissima NEES.

    PubMed

    Phan, Minh Giang; Phan, Tong Son; Matsunami, Katsuyoshi; Otsuka, Hideaki

    2006-03-01

    Four new natural neolignans and lignans, which were given the trivial names odoratisols A-D (1-4), together with (-)-licarin A, kachirachirol B, obovatifol, and machilin-I were isolated from the air-dried bark of the Vietnamese medicinal plant Machilius odoratissima NEES (Lauraceae). Their absolute structures were determined on the basis of spectroscopic analyses including circular dichroism spectra.

  14. Discerning the cows from the pasture when determining annual NEE and carbon budget

    NASA Astrophysics Data System (ADS)

    Ammann, Christof; Felber, Raphael; Neftel, Albrecht

    2015-04-01

    The CO2 exchange of ecosystems and the resulting annual net ecosystem exchange (NEE) and total carbon budget (soil carbon sequestration) is commonly investigated using the eddy covariance (EC) technique. For the carbon budget of managed ecosystems also the import and export of organic carbon has to be taken into account. Grazed pasture systems represent a special challenge because their respiration can considerably contribute to the measured CO2 flux, but this contribution depends on the spatial distribution of the cows relative to the footprint and thus is variable in time. This has implications for the gap filling of CO2 flux time series necessary to determine annual NEE. In few existing studies two procedures have been suggested to determine the NEE of grazed pasture: (a) discarding all cases with cows in the footprint and gap-filling the remaining dataset; (b) treating the cow respiration as part of total ecosystem respiration and gap fill the entire flux dataset including cow contributions. Both approaches rely on idealized assumptions and have limitations. In our study we evaluated and compared the two approaches (for the first time to our knowledge) for a grazed pasture in Switzerland. For this purpose, the grazing cows were equipped with GPS sensors to monitor their position relative to the flux footprint. We found that the resulting annual NEE strongly depends on the flux data selection (e.g. u* filtering) and the applied gap filling procedure. Using an optimized procedure, the annual NEE with approach (b) was several times larger than the result of approach (a), but the difference agreed fairly well with independent estimates of cow respiration. Necessary assumptions and requirements of the two approaches for the determination of the pasture carbon budget will be discussed.

  15. Regional-scale NEE estimates over 4 flux towers in the US

    NASA Astrophysics Data System (ADS)

    Dang, X.; Lai, C.; Hollinger, D. Y.; Munger, J. W.; Paw U, K.; Owensby, C.; Wofsy, S. C.; Schauer, A.; Ehleringer, J.

    2010-12-01

    We modeled regional carbon dioxide (CO2) fluxes based on midday mixing ratios measured in the canopy surface layer over 6 years (2002-2007) in four AmeriFlux stations. Applying an equilibrium boundary layer approach to focus on mean CO2 balance aggregated by the atmospheric boundary layer (ABL) processes, we estimated monthly average CO2 fluxes by inverting the difference between CO2 mixing ratios in the ABL and those in the free troposphere. We used a combination of NCAR/NCEP Reanalysis and ECMWF model data to estimate mean monthly rates of vertical transport between ABL and the free troposphere. Comparison between modeled net CO2 fluxes and tower-based eddy covariance NEE measurements suggests two interesting general patterns. First, modeled regional CO2 fluxes display inter- and intra-annual variations similar to the tower NEE fluxes observed in the Rannells Prairie and Wind River Forest, whereas model discrepancies were consistently found for the Harvard Forest and Howland Forest. Second, model discrepancies show distinct temporal patterns between the two northeastern U.S. forests. At the Howland Forest site, modeled CO2 fluxes showed a lag in the onset of growing-season uptake by two months behind that of tower measurements. At the Harvard Forest, modeled CO2 fluxes agreed with the timing of growing season uptake but underestimated the magnitude of observed NEE seasonal fluctuation. This modeling inconsistency among sites can be partially attributed to the likely misrepresentation of atmospheric transport and/or CO2 gradients between ABL and the free troposphere. Remote sensing-based land cover maps indicate that spatial heterogeneity in land use and cover was very likely to explain the majority of the modeling inconsistency. We suggest that the equilibrium boundary layer budget method can serve as a routine, diagnostic tool to interpret long-term NEE observations in flux networks, providing an intermediate-level analysis to complement aircraft

  16. Antifungal activity of nettle (Urtica dioica L.), colocynth (Citrullus colocynthis L. Schrad), oleander (Nerium oleander L.) and konar (Ziziphus spina-christi L.) extracts on plants pathogenic fungi.

    PubMed

    Hadizadeh, I; Peivastegan, B; Kolahi, M

    2009-01-01

    Anti-mycotic activity of the ethanol extracts from Nettle (Urtica dioica L.), Colocynth (Citrullus colocynthis L. Schrad), Konar (Ziziphus spina-christi L.) and Oleander (Nerium oleander L.) floral parts were screened in vitro against four important plant pathogenic fungi viz.; Alternaria alternate, Fusarium oxysporum, Fusarium solani and Rizoctonia solani using agar dilution bioassay. Extracts showed antifungal activity against all the tested fungi. Among the plants, Nettle and Colocynth were the most effective against A. alternate and R. solani while Oleander possesses the best inhibition on F. oxysporum and F. solani. Konar was the most effective extract by reducing the growth of Rizoctonia solani than other fungi. These results showed that extracts could be considered suitable alternatives to chemical additives for the control of fungal diseases in plants.

  17. The Importance of Winter for Controlling the Growing Season Net Ecosystem Exchange (NEE) of Boreal Forests

    NASA Astrophysics Data System (ADS)

    Oquist, M. G.; Peichl, M.; Ottosson Lofvenius, M.; Nilsson, M. B.

    2014-12-01

    It is becoming increasingly apparent that the winter season of high latitudes can be important for controlling a range of ecological and biogeochemical properties of northern ecosystems. Here we evaluate the importance of winter conditions on the carbon exchange between boreal forest systems and the atmosphere during the following growing season in order to elucidate any influence of inter-seasonal "memory" effects on carbon exchange properties of boreal forest ecosystems. The study is based on 5 years of continuous eddy covariance measurements at two ca 50 year old Norway spruce stands situated in mid- and northern Sweden, respectively (a total of 10 site years). The growing season net ecosystem exchange (NEE) ranged from -530 to -60 g C m-2 (negative values indicates carbon sinks). Environmental conditions during the growing season (e.g. temperature, radiation, length) only weakly explained the year-to-year variability in NEE. In contrast, up to 75% of the variation could be explained by the severity of the preceding winter (defined as the lowest observed average weekly air temperature) using an exponential response function. After warm winters the carbon sink properties were high as compared to those observed after cold winters. The winter conditions markedly affected the systems potential for carbon uptake in early summer. This presentation will address the potential mechanisms underpinning the observed correlations linking growing season carbon exchange to the conditions of the preceding winter. The influence of winter on the partitioned carbon fluxes of ecosystem respiration and gross primary productivity, respectively, will also be addressed. The results strongly indicate that controls on boreal forest carbon exchange can transcend across seasons. Understanding these mechanisms are integral for understanding the environmental drivers of atmospheric carbon exchange, allowing for accurate predictions of boreal forest NEE under both present and future climates.

  18. BOREAS TGB-1/TGB-3 NEE Data over the NSA Fen

    NASA Technical Reports Server (NTRS)

    Bellisario, Lianne; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor); Moore, Tim R.

    2000-01-01

    The BOReal Ecosystem-Atmosphere Study Trace Gas Biogeochemistry (BOREAS TGB-1) and TGB-3 teams collected several data sets that contributed to understanding the measured trace gas fluxes over sites in the Northern Study Area (NSA). This data set contains Net Ecosystem Exchange of CO2 (NEE) measurements collected with chambers at the NSA fen in 1994 and 1996. Gas samples were extracted approximately every 7 days from chambers and analyzed at the NSA lab facility. The data are provided in tabular ASCII files.

  19. Using model-data fusion to analyze the interannual variability of NEE of an alpine grassland

    NASA Astrophysics Data System (ADS)

    Scholz, Katharina; Hammerle, Albin; Hiltbrunner, Erika; Wohlfahrt, Georg

    2017-04-01

    To understand the processes and magnitude of carbon dynamics of the biosphere, modeling approaches are an important tool to analyze carbon budgets from regional to global scale. Here, a simple process-based ecosystem carbon model was used to investigate differences in CO2 fluxes of a high mountain grassland near Furka Pass in the Swiss central Alps at an elevation of about 2400 m a.s.l. during two growing seasons differing in snow melt date. Data on net ecosystem CO2 exchange (NEE) as well as meteorological conditions was available from 20.06.2013 - 08.10.2014 covering two snow free periods. The NEE data indicates that the carbon uptake during the growing season in 2013 was considerably lower than in 2014. To investigate whether the lower carbon uptake in 2013 was mainly due to the short growing season, an effect of biotic response to spring environmental conditions, or the direct effect of the weather conditions during the growing season, a modeling approach was applied. For this purpose, an ecosystem mass balance C model with 13 unknown parameters was constructed based on the DALEC model to represent the major C fluxes among six carbon pools (foliage, roots, necromass, litter, soil organic carbon and a labile pool to support leaf onset in spring) of the grassland ecosystem. Daily gross primary production was estimated by use of a sun/shade big-leaf model of canopy photosynthesis. By calibrating the model with NEE data from individual years, two sets of parameters were retrieved which were then used to run the model under environmental conditions of the same as well as the other year. The parameter estimation was done using DREAM, an algorithm for statistical inference of parameters using Bayesian statistics. In order to account for non-normality, heteroscedasticity and correlation of model residuals, a common problem in ecological modeling, a generalized likelihood function was applied. The results indicate that the late growing season start in 2013 led to a

  20. The clinical investigation of Citrullus colocynthis (L.) schrad fruit in treatment of Type II diabetic patients: a randomized, double blind, placebo-controlled clinical trial.

    PubMed

    Huseini, H Fallah; Darvishzadeh, F; Heshmat, R; Jafariazar, Z; Raza, Mohsin; Larijani, B

    2009-08-01

    Citrullus colocynthis (L.) Schrad fruit is an herbal medicine used by traditional herbalists for the treatment of diabetes in Iran. To determine its efficacy and toxicity, a 2 month clinical trial was conducted in 50 type II diabetic patients. Two groups of 25 each under standard antidiabetic therapy, received 100 mg C. colocynthis fruit capsules or placebos three times a day, respectively. The patients were visited monthly and glycosylated hemoglobin (HbA1c), fasting blood glucose, total cholesterol, LDL, HDL, triglyceride, aspartate transaminase, alanine transaminase, alkaline phosphatase, urea and creatinine levels were determined at the beginning and after 2 months. The results showed a significant decrease in HbA1c and fasting blood glucose levels in C. colocynthis treated patients. Other serological parameters levels in both the groups did not change significantly. No notable gastrointestinal side effect was observed in either group. In conclusion, C. colocynthis fruit treatment had a beneficial effect on improving the glycemic profile without severe adverse effects in type II diabetic patients. Further clinical studies are recommended to evaluate the long-term efficacy and toxicity of C. colocynthis in diabetic patients. Copyright 2009 John Wiley & Sons, Ltd.

  1. Evaluation of anti-inflammatory activity of Solanum xanthocarpum Schrad and Wendl (Kaṇṭakāri) extract in laboratory animals

    PubMed Central

    More, Shraddha K.; Lande, Anirudha A.; Jagdale, Priti G.; Adkar, Prafulla P.; Ambavade, Shirishkumar D.

    2013-01-01

    Context: Solanum xanthocarpum Schrad and Wendl (Kaṇṭakāri) is a diffuse herb with prickly stem, traditionally used for the treatment of inflammation and one in the group of daśamūla (group of ten herbs) herbs commonly used drug in Ayurveda. Aims: In continuation of search for potent natural anti-inflammatory agents, the present research work was planned to evaluate the anti-inflammatory activity of ethanol extract of S. xanthocarpum whole plant. Settings and Design: The ethanol extract was evaluated at dose 10, 30 and 100 mg/kg p.o. in rats. Materials and Methods: Using pharmacological screening models carrageenan induced rat paw edema, histamine induced rat paw edema and cotton pellet granuloma in rats. Statistical Analysis Used: Data obtained was analyzed statistically using analysis of variance followed by post-hoc Dunnett test, P < 0.05 is considered as statistically significant. Results: Acute treatment didn’t show anti-inflammatory activity against carrageenan and histamine induced paw edema. However, administration of 100 mg/kg p.o for 7 day reduced the granuloma formation in cotton pellet granuloma model. Conclusions: Present results support the traditional use of plant for anti-inflammatory activity. In brief, the results provide scientific pharmacological basis for the therapeutic use of S. xanthocarpum. PMID:24991071

  2. NEE and GPP dynamic evolution at two biomes in the upper Spanish plateau

    NASA Astrophysics Data System (ADS)

    Sánchez, María Luisa; Pardo, Nuria; Pérez, Isidro Alberto; García, Maria de los Angeles

    2014-05-01

    In order to assess the ability of dominant biomes to act as a CO2 sink, two eddy correlation stations close to each other in central Spain have been concurrently operational since March 2008 until the present. The land use of the first station, AC, is a rapeseed rotating crop consisting of annual rotation of non-irrigated rapeseed, barley, peas, rye, and sunflower, respectively. The land use of the second, CIBA, is a mixture of open shrubs/crops, with open shrubs being markedly dominant. The period of measurements covered variable general meteorological conditions. 2009 and 2012 were dominated by drought, whereas 2010 was the rainiest year. Annual rainfall during 2008 and 2009 was close to the historical averaged annual means. This paper presents the dynamic evolution of NEE-8d and GPP-8d observed at the AC station over five years and compares the results with those concurrently observed at the CIBA station. GGP 8-d estimates at both stations were determined using a Light Use Efficiency Model, LUE. Input data for the LUE model were the FPAR 8-d products supplied by MODIS, PAR in situ measurements, and a scalar f, varying between 0 and 1, to take account of the reduction in maximum PAR conversion efficiency, ɛ0, under limiting environmental conditions. f values were assumed to be dependent on air temperature and evaporative fraction, EF, which was considered a proxy of soil moisture. ɛ0, a key parameter, which depends on land use types, was derived through the results of a linear regression fit between the GPP 8-d eddy covariance composites observed and the LUE concurrent 8-d model estimates. Over the five-year study period, both biomes behaved as CO2 sinks. However, the ratio of the NEE-8d total accumulated at AC and CIBA, respectively, was close to a factor two, revealing the effectiveness of the studied crops as CO2 sinks. On an annual basis, accumulated NEE-8d exhibited major variability in both biomes. At CIBA, the results were largely dominated by the

  3. Enzyme inhibition, antioxidant and antibacterial potential of vasicine isolated from Adhatoda vasica Nees.

    PubMed

    Shahwar, Durre; Raza, Muhammad Asam; Tariq, Sidra; Riasat, Madiha; Ajaib, Mohammad

    2012-07-01

    Vasicine (1) was isolated from the ethanolic extract of Adhatoda vasica Nees (Acanthaceae) and the structure was confirmed using spectroscopic techniques. Acetylcholine esterase, trypsin, DPPH inhibition potential and FRAP assay were carried out using in vitro models. The results showed 38.4 ± 1.2% and 37.4 ± 1.1% activity in acetylcholine and trypsin inhibition assays respectively. The compound (1) exhibited significant DPPH inhibition activity (70.4 ± 1.3%, IC(50) = 212.3 ± 1.9 μM). A dose dependant behavior of vasicine (1), was indicated in the FRAP assay. Antibacterial activity was checked according to agar well diffusion assay and results revealed that vasicine (1) showed moderate activity.

  4. Improvement in the yield and quality of kalmegh (Andrographis paniculata Nees) under the sustainable production system.

    PubMed

    Verma, Rajesh Kumar; Verma, Sanjeet K; Pankaj, Umesh; Gupta, Anand K; Khan, Khushboo; Shankar, Karuna

    2015-02-01

    Andrographis paniculata Nees is an annual erect herb with wide medicinal and pharmacological applications due to the presence of andrographolide and other active chemical constituents. The large-scale cultivation of the kalmegh is not in practice. The aim of this study was to establish sustainable production systems of A. paniculata cv CIM-Megha with the application of different bioinoculants and chemical fertilisers. A. paniculata herb and andrographolide yield in the dried leaves was found to be highest (218% and 61.3%, respectively) in treatment T3 (NPK+Bacillus sp.) compared with T1 (control). The soil organic carbon, soil microbial respiration, soil enzymes activity and available nutrients improved significantly with combined application of bioinoculants and chemical fertilisers.

  5. Four New Kaurane Diterpenoids from the Chinese Liverwort Jungermannia comata Nees.

    PubMed

    Li, Rui-Juan; Wang, Song; Li, Gang; Zhou, Jin-Chuan; Zhang, Jiao-Zhen; Zhang, You-Ming; Shi, Guo-Sheng; Lou, Hong-Xiang

    2016-12-01

    In our continuing program to find new bioactive compounds from the Chinese liverworts, four new kaurane-type diterpenoids, (6β)-kaur-16-ene-6,9-diol (1), (6β,12β)-kaur-16-ene-6,9,12-triol (2), (6β)-kaur-16-ene-5,6,9-triol (3), and kaur-16-ene-9,19-diol (4), have been isolated from the Chinese liverwort Jungermannia comata Nees. Five known kaurane-type diterpenoids (5 - 9) and four known trachylobane-type diterpenoids (10 - 13) were also obtained. The structures of the new compounds were established unequivocally on the basis of spectroscopic data. The absolute configuration of compound 1 was established by comparing experimental and calculated electronic circular dichroism spectra.

  6. Simulating the impacts of land use in northwest Europe on Net Ecosystem Exchange (NEE): the role of arable ecosystems, grasslands and forest plantations in climate change mitigation.

    PubMed

    Abdalla, Mohamed; Saunders, Matthew; Hastings, Astley; Williams, Mike; Smith, Pete; Osborne, Bruce; Lanigan, Gary; Jones, Mike B

    2013-11-01

    In this study, we compared measured and simulated Net Ecosystem Exchange (NEE) values from three wide spread ecosystems in the southeast of Ireland (forest, arable and grassland), and investigated the suitability of the DNDC (the DeNitrification-DeComposition) model to estimate present and future NEE. Although, the field-DNDC version overestimated NEE at temperatures >5 °C, forest-DNDC under-estimated NEE at temperatures >5 °C. The results suggest that the field/forest DNDC models can successfully estimate changes in seasonal and annual NEE from these ecosystems. Differences in NEE were found to be primarily land cover specific. The annual NEE was similar for the grassland and arable sites, but due to the contribution of exported carbon, the soil carbon increased at the grassland site and decreased at the arable site. The NEE of the forest site was an order of magnitude larger than that of the grassland or arable ecosystems, with large amounts of carbon stored in woody biomass and the soil. The average annual NEE, GPP and Reco values over the measurement period were -904, 2379 and 1475 g C m(-2) (forest plantations), -189, 906 and 715 g C m(-2) (arable systems) and -212, 1653 and 1444 g C m(-2) (grasslands), respectively. The average RMSE values were 3.8 g C m(-2) (forest plantations), 0.12 g C m(-2) (arable systems) and 0.21 g C m(-2) (grasslands). When these models were run with climate change scenarios to 2060, predictions show that all three ecosystems will continue to operate as carbon sinks. Further, climate change may decrease the carbon sink strength in the forest plantations by up to 50%. This study supports the use of the DNDC model as a valid tool to predict the consequences of climate change on NEE from different ecosystems.

  7. The genus Spathius Nees (Hymenoptera, Braconidae, Doryctinae) in Mexico: occurrence of a highly diverse Old World taxon in the Neotropics

    PubMed Central

    Belokobylskij, Sergey A.; Zaldívar-Riverón, Alejandro

    2014-01-01

    Abstract Two new species of the parasitoid wasp genus Spathius Nees (Braconidae: Doryctinae) from Mexico, S. mexicanus sp. n. and S. chamelae sp. n., are described and illustrated. These represent the second and third described species of this highly diverse Old World genus in the Neotropics, and the first described species recorded for the Mexican territory. PMID:25147464

  8. The genus Spathius Nees (Hymenoptera, Braconidae, Doryctinae) in Mexico: occurrence of a highly diverse Old World taxon in the Neotropics.

    PubMed

    Belokobylskij, Sergey A; Zaldívar-Riverón, Alejandro

    2014-01-01

    Two new species of the parasitoid wasp genus Spathius Nees (Braconidae: Doryctinae) from Mexico, S. mexicanus sp. n. and S. chamelae sp. n., are described and illustrated. These represent the second and third described species of this highly diverse Old World genus in the Neotropics, and the first described species recorded for the Mexican territory.

  9. Overview of the NEES-Soft Experimental Program for Seismic Risk Reduction of Soft-Story Woodframe Buildings

    Treesearch

    John W. van de Lindt; Pouria Bahmani; Steven E. Pryor; Gary Mochizuki; Mikhail Gershfeld; Weichiang Pang; Ershad Ziaei; Elaina N. Jennings; Michael D. Symans; Xiaoyun Shao; Jingjing Tian; Doug Rammer

    2014-01-01

    The existence of thousands of soft-story woodframe buildings in California has been recognized as a disaster preparedness problem resulting in mitigation efforts throughout the state. The considerable presence of these large multi-family buildings in San Francisco prompted the city to mandate their retrofitting over the next seven years. The NEES-Soft project, whose...

  10. Historical Mortality of Valley Oak (Quercus lobata, Nee) in the Santa Ynez Valley, Santa Barbara County, 1938-1989

    Treesearch

    Rodney W. Brown; Frank W. Davis

    1991-01-01

    The range and abundance of valley oak (Quercus lobata, Nee) have steadily decreased in the last 100 years due to low rates of regeneration during this period. Documented low rates of sapling recruitment must be compared to adult mortality rates in order to evaluate the severity of this decline. The purpose of this research is to measure and analyze...

  11. Glycomyces endophyticus sp. nov., an endophytic actinomycete isolated from the root of Carex baccans Nees.

    PubMed

    Qin, Sheng; Wang, Hai-Bin; Chen, Hua-Hong; Zhang, Yu-Qin; Jiang, Cheng-Lin; Xu, Li-Hua; Li, Wen-Jun

    2008-11-01

    An actinomycete, designated strain YIM 56134(T), was isolated from the root of a Chinese medicinal plant, Carex baccans Nees, collected from Yunnan, south-west China, and subjected to a polyphasic taxonomic study. An analysis of 16S rRNA gene sequence similarities showed that strain YIM 56134(T) was a member of the genus Glycomyces, being most closely related to Glycomyces algeriensis NRRL B-16327(T) (99.0 % similarity), Glycomyces lechevalierae DSM 44724(T) (99.0 %), Glycomyces rutgersensis IFO 14488(T) (98.9 %) and Glycomyces harbinensis IFO 14487(T) (98.7 %). Strain YIM 56134(T) could be distinguished from other established Glycomyces species on the basis of relatively low sequence similarity (<97 %). Phenotypic and chemotaxonomic data supported the affiliation of this strain to the genus Glycomyces. The results of DNA-DNA hybridization and some physiological and biochemical tests allowed differentiation of the strain from related Glycomyces species. Therefore, strain YIM 56134(T) represents a novel species of the genus Glycomyces, for which the name Glycomyces endophyticus sp. nov. is proposed. The type strain is YIM 56134(T) (=KCTC 19152(T) =DSM 45002(T)).

  12. Anti-inflammatory and antimicrobial properties of pyrroloquinazoline alkaloids from Adhatoda vasica Nees.

    PubMed

    Singh, Bharat; Sharma, Ram Avtar

    2013-03-15

    Adhatoda vasica Nees, Acanthaceae, is well known plant in Ayurveda and Unani medicine. The purpose of this study was to characterize the most bioactive phytochemicals viz., vasicine, vasicinone, vasicine acetate, 2-acetyl benzyl amine, vasicinolone present in the chloroform fraction having anti-inflammatory and antimicrobial activities. The anti-inflammatory activity was tested by using carrageenan and CFA-model induced paw oedema. The antimicrobial activity of isolated compounds was assessed by using the microdilution method. The observed results revealed that vasicine showed most potent anti-inflammatory effects (59.51%) at the dose of 20.0mg/kg at 6h after carrageenan injection and maximum inhibition rate was observed of vasicinone (63.94%) at the dose of 10.0mg/kg at 4 days after CFA injection. The strong antibacterial activity was exhibited by vasicine at 20μg/ml dose against E. coli and also demonstrated maximum antifungal activity against C. albicans at the dose of >55μg/ml. All the five alkaloids demonstrated significant anti-inflammatory and antimicrobial activities. Copyright © 2012 Elsevier GmbH. All rights reserved.

  13. Detoxification of aflatoxin B1 by an aqueous extract from leaves of Adhatoda vasica Nees.

    PubMed

    Vijayanandraj, S; Brinda, R; Kannan, K; Adhithya, R; Vinothini, S; Senthil, K; Chinta, Ramakoteswara Rao; Paranidharan, V; Velazhahan, R

    2014-04-01

    The effectiveness of aqueous extracts of various medicinal plants in detoxification of aflatoxin B1 (AFB1) was tested in vitro by thin-layer chromatography and enzyme-linked immunosorbent assay (ELISA). Among the different plant extracts, the leaf extract of Vasaka (Adhatoda vasica Nees) showed the maximum degradation of AFB1 (≥ 98%) after incubation for 24h at 37 °C. The aflatoxin detoxifying activity of the A. vasica leaf extract was significantly reduced by heating to 100 °C for 10 min or autoclaving at 121 °C for 20 min. Dialysis had no effect on aflatoxin detoxifying ability of A. vasica extract and the dialyzed extract showed similar level of detoxification of AFB1 as that of the untreated extract. A time course study of aflatoxin detoxification by A. vasica extract showed that 69% of the toxin was degraded within 6h and ≥ 95% degradation was observed after 24h of incubation. Detoxification of AFB1 by A. vasica extract was further confirmed by liquid chromatography-mass spectrometry (LC-MS) analysis. Phytochemical analysis revealed the presence of alkaloids in methanolic extract of A. vasica leaves. A partially purified alkaloid from A. vasica leaves by preparative TLC exhibited strong AFB1 detoxification activity. Copyright © 2013 Elsevier GmbH. All rights reserved.

  14. Clara Haber, nee Immerwahr (1870–1915): Life, Work and Legacy

    PubMed Central

    2016-01-01

    Abstract We examine the life, work, and legacy of Clara Haber, nee Immerwahr, who became the first woman to earn a doctorate from the University of Breslau, in 1900. In 1901 she married the chemist Fritz Haber. With no employment available for female scientists, Clara freelanced as an instructor in the continued education of women, mainly housewives, while struggling not to become a housewife herself. Her duties as a designated head of a posh household hardly brought fulfillment to her life. The outbreak of WWI further exacerbated the situation, as Fritz Haber applied himself in extraordinary ways to aid the German war effort. The night that he celebrated the “success” of the first chlorine cloud attack, Clara committed suicide. We found little evidence to support claims that Clara was an outspoken pacifist who took her life because of her disapproval of Fritz Haber's involvement in chemical warfare. We conclude by examining “the myth of Clara Immerwahr” that took root in the 1990s from the perspective offered by the available scholarly sources, including some untapped ones. PMID:27099403

  15. Rapid propagation of lemongrass (Cymbopogon flexuosus (Nees) Wats.) through somatic embryogenesis in vitro.

    PubMed

    Nayak, S; Debata, B K; Sahoo, S

    1996-01-01

    Somatic embryos induced from callus cultures of lemongrass [Cymbopogon flexuosus (Nees) Wats.] on Murashige and Skoog medium supplemented with 5 mg/l of 2,4-D, 0.1 mg/l of NAA and 0.5 mg/l of Kn developed into plantlets when plated on a medium supplemented with 3 mg/l of BA, 1 mg/l of GA3 and 0.1 mg/l of NAA. The regeneration potential of callus was retained for more than 2 years on the nutrient medium supplemented with comparatively lower levels of growth regulators (2,4-D at 2 mg/l, NAA at 0.1 mg/l and Kn at 0.25 mg/l). Approximately 30-35 plantlets were produced after two months of culture per 100 mg of callus inoculated. Regenerants were transplanted into soil and transferred to the field for assessment of various morphological and biochemical characteristics. The results of 1 year of field trials showed that plants derived from somatic embryoids were more uniform in all the characteristics examined when compared with the field performance of plants raised through slips by standard propagation procedures. Thus, a procedure has been developed for high frequency long term plant production of lemongrass through in vitro methods.

  16. Hydrochemistry in the Tropical Forested River: A Case Study in Nee Soon Catchment Streams

    NASA Astrophysics Data System (ADS)

    Nguyen, T. C. T.; WIN, S. H.; Lim, M. H.; Pai, K.; Khairun Nisha, B. M. R.; Ziegler, A. D.; Wasson, R.; Cantarero, S. I.

    2016-12-01

    A total of 779 water samples from the Nee Soon Nature Reserve, a 5km2 catchment in humid tropical Singapore, were collected in low-flow (May 2014 to Nov 2015) and high-flow (May 2014 to June 2015) conditions for determination of spatial and temporal distributions of major ions (Na+, Ca2+, K+, Mg2+, Cl-, HCO3-, NO3-, SO42- and F-) in the streams. In low-flow conditions all cations and Cl-, HCO3-, SO42- showed significant enrichment in the lower compared to the upper catchment, whereas, NO3- and F- had the opposite pattern. In high-flow conditions, the spatial distribution patterns of the ions was largely unchanged across the catchment except that F- was enriched in the lower compared to the upper catchment. Except for Cl-, HCO3- and NO3-, all other ions were higher in storm periods. Among possible sources (atmospheric input, anthropogenic impact and rock weathering), rainfall played an important role in controlling river Cl- and Na+; silicate rock weathering was possibly the source for Ca2+,Mg2+, HCO3- and some of the Na+; all of the SO42- probably comes from pollution by anthropogenic activities. This study provides new data and insights for the understudied South East Asia region.

  17. Anti-inflammatory, analgesic and antipyretic effects of Lepidagathis anobrya Nees (Acanthaceae).

    PubMed

    Richard, Sawadogo Wamtinga; Marius, Lompo; Noya, Somé; Innocent Pierre, Guissou; Germaine, Nacoulma-Ouedraogo Odile

    2011-01-01

    This study investigated the general acute, anti-inflammatory, analgesic and antipyretic effects of methanol extract of Lepidagathis anobrya Nees (Acanthaceae). Carrageenan-induced rat paw edema and croton oil-induced ear edema in rats were used for the evaluation of general acute anti-inflammatory effects. Acetic acid-induced writhing response and yeast-induced hyperpyrexia in mice were used to evaluate the analgesic and antipyretic activities respectively. The extract at doses of 10, 25, 50 and 100 mgkg(-1) for carrageenan test and doses of 0.5 mg/ear for croton oil test induced a significant reduction (p < 0.001) of paw and ear edemas in rats. In the analgesic and antipyretic tests, the extract has shown a significant inhibition of writhes and hyperpyrexia with all the doses used when compared to the untreated control group. These results clearly show the anti-inflammatory, analgesic and antipyretic effects of the methanol extract of Lepidagathis anobrya and give the scientific basis for its traditional use. Further studies are needed to clarify the mechanism of action and the components responsible for these pharmacological effects.

  18. Clara Haber, nee Immerwahr (1870-1915): Life, Work and Legacy.

    PubMed

    Friedrich, Bretislav; Hoffmann, Dieter

    2016-03-01

    We examine the life, work, and legacy of Clara Haber, nee Immerwahr, who became the first woman to earn a doctorate from the University of Breslau, in 1900. In 1901 she married the chemist Fritz Haber. With no employment available for female scientists, Clara freelanced as an instructor in the continued education of women, mainly housewives, while struggling not to become a housewife herself. Her duties as a designated head of a posh household hardly brought fulfillment to her life. The outbreak of WWI further exacerbated the situation, as Fritz Haber applied himself in extraordinary ways to aid the German war effort. The night that he celebrated the "success" of the first chlorine cloud attack, Clara committed suicide. We found little evidence to support claims that Clara was an outspoken pacifist who took her life because of her disapproval of Fritz Haber's involvement in chemical warfare. We conclude by examining "the myth of Clara Immerwahr" that took root in the 1990s from the perspective offered by the available scholarly sources, including some untapped ones.

  19. Pancreatic effect of andrographolide isolated from Andrographis paniculata (Burm. f.) Nees.

    PubMed

    Nugroho, Agung Endro; Rais, Ichwan Ridwan; Setiawan, Iwan; Pratiwi, Pramita Yuli; Hadibarata, Tony; Tegar, Maulana; Pramono, Suwidjiyo

    2014-01-01

    Andrographis paniculata (Burm. f.) Nees is a plant that originates from India and grows widely to Southeast which used for several purposes mainly as treatment of diabetes mellitus so the aim of this study was evaluate andrographolide for its pancreatic effect in neonatal streptozotocin (STZ)-induced diabetic rats, a model of type 2 diabetic rats. Diabetic condition was induced with an intraperitoneal injection of 90 mg kg(-1) streptozotocin in two-day-old rats. After three months, the neonatal STZ-induced diabetic rats were treated with andrographolide or andrographolide-enriched extract of A. paniculata (AEEAP) for 8 consecutive days. Pancreatic effect was evaluated by estimating mainly the preprandial and postprandial blood glucose levels and other parameters such as morphology of pancreatic islet, beta cells density and morphology and immunohistochemically pancreatic insulin. Andrographolide significantly (p < 0.05) decreased the levels of blood glucose and improved diabetic rat islet and beta cells. However, AEEAP exhibited moderate hypoglycaemic effects on the blood glucose levels. Moderate changes in beta cells were observed after AEEAP treatment. They could restore decreasing of pancreatic insulin contents. Based on these results andrographolide and AEEAP exhibited pancreatic actions in neonatal STZ-induced diabetic rats. The activity of andrographolide was more effective than this of AEEAP.

  20. Glycosidic conjugates of C13 norisoprenoids, monoterpenoids, and cucurbates in Boronia megastigma (Nees).

    PubMed

    Cooper, Chris M; Davies, Noel W; Motti, Cherie A; Menary, Robert C

    2011-03-23

    Analysis of a methanolic extract of marc from Boronia megastigma (Nees) using LC-MS (APCI, nominal mass) provided strong evidence for the presence of both glycosides and malonyl glycosides of methyl cucurbates, C13 norisoprenoids including megastigmanes, and monoterpene alcohols. Subsequent fractionation of an extract from the marc using XAD-2 and LH 20 chromatography followed by LC-UV/MS-SPE-NMR and accurate mass LC-MS resulted in the isolation and identification of (1R,4R,5R)-3,3,5-trimethyl-4-[(1E)-3-oxobut-1-en-1-yl]cyclohexyl β-D-glucopyranoside (3-hydroxy-5,6-dihydro-β-ionone-β-D-glucopyranoside); 3,7-dimethylocta-1,5-diene-3,7-diol-3-O-β-D-glucopyranoside; and a methyl {(1R)-3-(β-D-glucopyranosyloxy)-2-[(2Z)-pent-2-en-1-yl]cyclopentyl}acetate stereoisomer (a methyl cucurbate-β-D-glucopyranoside); and provided evidence for 3,7-dimethylocta-1,5-diene-3,7-diol-3-O-(6'-O-malonyl)-β-D-glucopyranoside in boronia flowers.

  1. [Effects of Alternaria tenuis nees on Trifolium repens L. under Cu stress].

    PubMed

    Chu, Ling; Shao, Deng-hui; Jin, Song; Wu, Xue-feng

    2007-11-01

    With pot culture, this paper studied the effects of Alternaria tenuis Nees inoculation on the eco-physiological indices of Trifolium repens L. leaf under Cu stress. The results showed that in the control (not inoculated with the pathogen), the contents of photosynthetic pigments (chlorophyll a, b, a + b and carotenoid) and soluble protein in T. repens leaves decreased markedly with increasing Cu concentration (0-3000 mg x kg(-1)). The enhancement of cellular membrane lipids peroxidation with the increase of Cu concentration led to a rapid accumulation of malondialdehyde (MDA), the damage on cellular membrane structure, and an increase of electric conductivity. The balance of active oxygen metabolism systems was broken, SOD and CAT activities decreased, while POD activity increased. After inoculation with A. tenuis, the damages of Cu on plant membrane systems and active oxygen metabolism systems aggravated, the contents of photosynthetic pigments and soluble protein and the activities of SOD and CAT decreased to different degree, while the electric conductivity, MDA content and POD activity increased markedly, compared with the control.

  2. Assimilation of NEE and CO2-concentrations into the land-surface scheme of the MPI Earth System Model

    NASA Astrophysics Data System (ADS)

    Schürmann, Gregor Josef; Köstler, Christoph; Kaminski, Thomas; Giering, Ralf; Scholze, Marko; Carvalhais, Nuno; Kattge, Jens; Reichstein, Markus; Papale, Dario; Rödenbeck, Christian; Schnur, Reiner; Reick, Christian; Zaehle, Sönke

    2013-04-01

    Uncertainties of land surface models are to a large extent a consequence of uncertainties in their parametrisation and parameter values. Understanding and reducing these uncertainties is important to reduce the spread in global carbon cycle and therefore climate change projections. For this purpose, we developed a Carbon Cycle Data Assimilation System (CCDAS) for the land surface scheme (JSBACH) of the MPI Earth system model as a tool to systematically confront observations with the model. Observations representative for different temporal and spatial scales and processes, such as plant trait observations, point scale flux measurements, and globally integrating CO2 abundance monitoring, can be incorporated into this CCDAS to estimate net land-atmosphere carbon fluxes that are consistent with the observations and the model structure. Here we present the latest results of the MPI-CCDAS using observations of net ecosystem exchange of CO2 (NEE) and atmospheric CO2 concentrations. Eddy-covariance based measurements of NEE constrain the modelled carbon cycle on the scale of the flux measurement footprint at hourly time scale. The assimilation of CO2-concentration requires an observational operator that links modelled NEE with observed CO2-concentrations, provided by the the atmospheric transport model TM3. The concentrations are observed at a network of atmospheric monitoring stations and provide a large-scale integrated view of the terrestrial carbon cycle at seasonal and inter-annual time scales. Given the data streams complementarity, we evaluate its individual role in constraining the net land-atmosphere carbon exchange and discuss the benefits of its simultaneous assimilation. Additionally, we explore the importance of parameter priors, model and measurement uncertainties in the assimilation procedure to assess the robustness of NEE estimates. Our results emphasize the importance of integrating multiple data streams towards more comprehensive assessments of

  3. Antidiabetic and antihiperlipidemic effect of Andrographis paniculata (Burm. f.) Nees and andrographolide in high-fructose-fat-fed rats

    PubMed Central

    Nugroho, Agung Endro; Andrie, Mohamad; Warditiani, Ni Kadek; Siswanto, Eka; Pramono, Suwidjiyo; Lukitaningsih, Endang

    2012-01-01

    Objectives: Andrographis paniculata (Burm. f.) Nees originates from India and grows widely in many areas in Southeast Asian countries. Andrographis paniculata (Burm. f.) Nees has shown an antidiabetic effect in type 1 DM rats. The present study investigates the purified extract of the plant and its active compound andrographolide for antidiabetic and antihyperlipidemic effects in high-fructose-fat-fed rats, a model of type 2 DM rats. Materials and Methods: Hyperglycemia in rats was induced by high-fructose-fat diet containing 36% fructose, 15% lard, and 5% egg yolks in 0.36 g/200 gb.wt. 55 days. The rats were treated with the extract or test compound on the 50th day. Antidiabetic activity was measured by estimating mainly the pre– and postprandial blood glucose levels and other parameters such as cholesterol, LDL, triglyceride, and body weight. Results: The purified extract and andrographolide significantly (P<0.05) decreased the levels of blood glucose, triglyceride, and LDL compared to controls. However, no changes were observed in serum cholesterol and rat body weight. Metformin also showed similar effects on these parameters. Conclusions: Andrographis paniculata (Burm. f.) Nees or its active compound andrographolide showed hypoglycemic and hypolipidemic effects in high-fat-fructose-fed rat. PMID:22701250

  4. Herb-drug interaction of Andrographis paniculata (Nees) extract and andrographolide on pharmacokinetic and pharmacodynamic of naproxen in rats.

    PubMed

    Balap, Aishwarya; Lohidasan, Sathiyanarayanan; Sinnathambi, Arulmozhi; Mahadik, Kakasaheb

    2017-01-04

    Andrographis paniculata Nees (Acanthacae) have broad range of pharmacological effects such as hepatoprotective, antifertility, antimalarial, antidiabetic, suppression of various cancer cells and anti-inflammatory properties and is widely used medicinal plant in the traditional Unani and Ayurvedic medicinal systems. Andrographolide (AN) is one of the active constituent of the A. paniculata Nees extract (APE). They have been found in many traditional herbal formulations in India and proven to be effective as anti-inflammatory drug. To evaluate the pharmacokinetic and pharmacodynamic (anti arthritic) herb-drug interactions of A. paniculata Nees extract (APE) and pure andrographolide (AN) with naproxen (NP) after oral co-administration in wistar rats. After oral co-administration of APE (200mg/Kg) and AN (60mg/kg) with NP (7.5mg/kg) in rats, drug concentrations in plasma were determined using HPLC method. The main pharmacokinetic parameters of Cmax, tmax, t1/2, MRT, Vd, CL, and AUC were calculated by non-compartment model. Change in paw volume, mechanical nociceptive threshold, mechanical hyperalgesia, histopathology and hematological parameters were evaluated to study antiarthritic activity. Co-administration of NP with APE and pure AN decreased systemic exposure level of NP in vivo. The Cmax, tmax, AUC0-t of NP was decreased. In pharmacodynamic study, NP (10mg/kg) alone and NP+AN (10+60mg/kg) groups exhibited significant synergistic anti-arthritic activity as compared to groups NP+APE, APE and AN alone. The results obtained from this study suggested that NP, APE and pure AN existed pharmacokinetic herb-drug interactions in rat which is correlated with anti-arthritic study. The knowledge regarding possible herb-drug interaction of NP might be helpful for physicians as well as patients using AP. So further studies should be done to understand the effect of other herbal ingredients of APE on NP as well as to predict the herb-drug interaction in humans. Copyright © 2016

  5. An approach to assess NEE and C-costs associated with an energy-crop production at different erosion-induced transient states in a typical Northeastern Germany landscape using process-based agroecosystem modeling

    NASA Astrophysics Data System (ADS)

    Chatskikh, D.; Nendel, C.; Hagemann, U.; Specka, X.; Augustin, J.; Sommer, M.; Van Oost, K.

    2012-04-01

    Net Ecosystem Exchange (NEE) and C-costs associated with energy-crop production systems which are outside of NEE must be determined to suggest optimal mitigation options. In theory, NEE can be positive, if SOC is building up, neutral or balanced, with no change in SOC, or negative, if SOC is lost as a result of a soil degradation processes. Unclearness in complex multiscale interactions between different processes in the landscape in combination with a well-known wide range of uncertainties around NEE estimations makes these estimations for landscape scale scarce. In this study we used a process-based modeling to assess C-costs associated with soil erosion, assessing NEE at different erosion-induced transient states in the experiment settled Northeastern Germany (near Dedelow) in a representative section of younger landscape of hummocky ground moraine (CarboZALF-D). We used Monica, a soil-crop-atmosphere model, which is well-validated for various crops and soil in Germany. In the model, NEE (=-NEP) refer to NPP minus C losses in heterotrophic respiration, while NBE (=-NBP) refers to the change in SOC stocks after C losses due to regular (e.g. soil erosion) or occasional (e.g. harvest) disturbances. In this study we applied Monica to analyze relationships between past geomorphic processes, landscape position, crop growth and NEE. In this study we were interested in general trends and associated agroecosystem properties, rather than on magnitude of the fluxes. The results showed that past soil redistribution affected NEE at both positions, while the Monica-based scenarios in combination with data-based interpolations helped to interpret the NEE budgets. The model captured the magnitude of differences in the daily NEE values, but also the differences in an accumulated NEE fluxes between different erosion-induced transient states. Thus for both eroded and deposited positions NEE was negative. However absolute values of NEE were smaller for the deposited site compare to

  6. Long Term Pattern in Runoff Doc Fluxes in Two Boreal Upland Forested Catchments: does the Increasing Nee Affect Doc Fluxes?

    NASA Astrophysics Data System (ADS)

    Pumpanen, J. S.; Lindén, A.; Miettinen, H.; Kolari, P.; Ilvesniemi, H.; Hari, P.; Heinonsalo, J.; Vesala, T.; Back, J. K.; Berninger, F.; Ojala, A.

    2013-12-01

    Part of the carbon fixed in terrestrial ecosystems is transferred through streams and rivers to lakes and the carbon is finally released as CO2 to the atmosphere through respiration or buried into lake sediments. Recently it has been shown that lake and stream water dissolved/total organic carbon (DOC/TOC) concentrations throughout the boreal zone are increasing. There are several theories which could explain this trend; land use changes, decrease in atmospheric acid deposition, changes in seasonal patterns in temperature and precipitation and increase in below ground C allocation due to increase in atmospheric CO2 concentration or soil warming. Here, we tested a hypothesis that increase in photosynthesis is reflected in soil water DOC concentrations and finally in DOC fluxes from the catchment. We used a 15-year-long continuous monitoring data on catchment runoff, DOC concentration in the runoff, GPP, TER and NEE of the ecosystem of two small upland boreal catchment areas in Southern Finland to explain the long-term trends in runoff DOC fluxes. We also studied the long term trends in the amount, DOC concentration and pH of through fall over the study period ranging from 1998 to 2012. The average DOC concentration in runoff water was 3.43-4.0 mg L-1 and it increased in both catchments over the study period (P<0.001) along with soil temperature. The annual DOC fluxes (calculated as runoff x DOC concentration) ranged from a dry year minimum of 201 mg m-2 to wet year maximum of 1886 mg m-2. Also the DOC fluxes increased significantly over the course of the study period, but only during wet years. Annual net ecosystem exchange (NEE) (P<0.002) and total ecosystem respiration (TER) (P<0.007) increased significantly during the study period whereas GPP did not show any increasing or decreasing trend (P<0.347). Annual DOC fluxes were not significantly correlated with annual NEE, GPP or TER except for wet years when one of the catchments showed increasing trend in DOC fluxes

  7. What have we Learned after a Decade of Experiments and Monitoring at the NEES@UCSB Permanently Instrumented Field Sites?

    NASA Astrophysics Data System (ADS)

    Steidl, J. H.; Civilini, F.; Seale, S. H.; Hegarty, P.

    2013-12-01

    The Wildlife Liquefaction Array (WLA) and Garner Valley Downhole Array (GVDA) located in southern California are facilities that for the last decade have been supported under the National Science Foundations George E. Brown, Jr., Network for Earthquake Engineering Simulation (NEES) program. These densely instrumented geotechnical and structural engineering field sites continuously record both acceleration and pore pressure, with accelerometers located on the surface and at various depths below the surface, and pore pressure transducers installed at depth within the liquefiable layers. Permanently instrumented structures for examining soil-foundation-structure interaction and a permanent cross-hole array at the sites have transformed these sites into multi-disciplinary earthquake engineering research facilities. Over the last decade, local and regional seismic activity, including multiple extremely active earthquake swarms, have produced a valuable new data set providing a unique opportunity to observe site response and the evolution of pore pressure generation with time throughout the liquefiable layer at an unprecedented level of detail. In addition to the earthquakes provided by nature, active testing experiments using the mobile shakers from NEES@UTexas and NEES@UCLA have produced an equally valuable data set on both site characterization studies and soil-foundation-structure interaction. The new observations of pore pressure and acceleration with depth are providing in situ empirical evidence documenting the range of ground motion levels at which the onset of nonlinear behavior and excess pore pressure begins, augmenting previous case history data, and laboratory data from cyclic tri-axial and centrifuge testing. The largest static pore pressure increases observed in the 'NEES' decade of monitoring were generated by four events at the WLA site, ranging in magnitude from 4.6 to 5.4 and all at distances less than 10km from the site. The largest peak horizontal

  8. Effects of Andrographis paniculata Nees on growth, development and reproduction of malarial vector Anopheles stephensi Liston (Diptera: Culicidae).

    PubMed

    Kuppusamy, C; Murugan, K

    2010-12-01

    The use of environment friendly and easily biodegradable natural insecticides of plant origin has received progressively more attention as insecticide alternatives for the control of medically important mosquito vectors. The ethanol and methanol extracts of Andrographis paniculata Nees were evaluated for its effects on growth, development and reproduction of malarial vector Anopheles stephensi Liston. After 8 days of treatment, 88.60 and 85.25% of the larvae treated at 35p.p.m. failed to emerge in ethanol and methanol extracts respectively. In addition, the duration of larval instars and the total development time were prolonged, while female longevity and fecundity were markedly decreased. The suppression of pupation and adult emergence was probably due to juvenile hormone analog similarities in combination with growth regulators and toxicity, which reduced the overall performance of the malaria vector An. stephensi.

  9. Long term pattern in runoff DOC fluxes in two boreal upland forested catchments: does the increasing NEE affect DOC fluxes?

    NASA Astrophysics Data System (ADS)

    Pumpanen, Jukka; Lindén, Aki; Miettinen, Heli; Kolari, Pasi; Ilvesniemi, Hannu; Mammarella, Ivan; Hari, Pertti; Nikinmaa, Eero; Heinonsalo, Jussi; Bäck, Jaana; Ojala, Anne; Vesala, Timo

    2014-05-01

    Part of the carbon fixed in terrestrial ecosystems is transferred through streams and rivers to lakes and the carbon is finally released as CO2 to the atmosphere through respiration or buried into lake sediments. Recently it has been shown that lake and stream water dissolved/total organic carbon (DOC/TOC) concentrations throughout the boreal zone are increasing. There are several theories which could explain this trend; land use changes, decrease in atmospheric acid deposition, changes in seasonal patterns in temperature and precipitation and increase in below ground C allocation due to increase in atmospheric CO2 concentration or soil warming. Here, we tested a hypothesis that increase in photosynthesis is reflected in soil water DOC concentrations and finally in DOC fluxes from the catchment. We used a 15-year-long continuous monitoring data on catchment runoff, DOC concentration in the runoff, GPP, TER and NEE of the ecosystem of two small upland boreal catchment areas in Southern Finland to explain the long term trends in runoff DOC fluxes. We also studied the long term trends in the amount, DOC concentration and pH of throughfall over the study period ranging from 1998 to 2012. Our results indicate that the DOC concentration and the DOC fluxes have increased over the last 15 years. The DOC flux was mainly determined by the amount of runoff flow but in years when the runoff flow was above the long term average the NEE was a more important explanatory factor for annual DOC fluxes than the annual temperature sum.

  10. Inter-annual variability of year-round NEE over 18 years, and environmental controls on seasonal patterns at an arctic wet sedge tundra, CMDL Barrow, Alaska

    NASA Astrophysics Data System (ADS)

    Kalhori, A. A. M.; Oechel, W. C.; Goodrich, J. P.; Gioli, B.; Burba, G. G.; Shen, S. S. P.; Murphy, P.; Zona, D.

    2016-12-01

    To refine understanding of the total annual carbon balance in the Arctic, it is critical to extend long-term site-level CO2 flux data collection. These data are critical to addressing the environmental controls and processes responsible for temporal variability and seasonal patterns of net ecosystem exchange of CO2 (NEE). This dataset represents the longest running eddy covariance tower in the Arctic, which is located in an Alaskan wet sedge tundra ecosystem and is adjacent to the NOAA Climate Monitoring & Diagnostic Laboratory (CMDL). In addition to analyzing the year-to-year controls on NEE and its long-term trends, this work will complement a parallel study of the 40 year record of CO2 concentration measurements from the NOAA Barrow synoptic sampling station. For long-term, retrospective measurements, missing values are unavoidable, resulting from system failure, sensors icing-up during winter, losing network connections due to the harsh conditions, necessary instrument repairs, etc. Therefore, to analyze the annual sums, diurnal patterns, and seasonal vs. annual fluxes, the choice of gap-filling approach is critical and can dominate the magnitude of uncertainties, especially for periods with long gaps (> 1 month). We have applied different gap-filling methods such as artificial neural networks (ANN), and multiple linear regression (MLR) driven by micrometeorological parameters in an effort to minimize the associated uncertainties. Following gap-filling, a stepwise multiple regression against meteorological drivers including average summer PAR, average air and soil temperature, growing season length, duration of the zero curtain, growing degree days (GDD), date of snow melt, date of freeze up, and length of the summer was applied to determine the parameters that best explain the magnitude and sign of NEE in different seasons. These statistical analyses show that growing degree days were strongly correlated with summer NEE, which increased with higher GDD

  11. Evaluation of the Allelopathic Potential of Leaf, Stem, and Root Extracts of Ocotea pulchella Nees et Mart.

    PubMed

    Candido, Lafayette P; Varela, Rosa M; Torres, Ascensión; Molinillo, José M G; Gualtieri, Sonia C J; Macías, Francisco A

    2016-08-01

    Despite the increase in recent decades in herbicide research on the potential of native plants, current knowledge is considered to be low. Very few studies have been carried out on the chemical profile or the biological activity of the Brazilian savanna (Cerrado) species. In the study reported here, the allelopathic activity of AcOEt and MeOH extracts of leaves, stems, and roots from Ocotea pulchella Nees was evaluated. The extracts were assayed on etiolated wheat coleoptiles. The AcOEt leaf extract was the most active and this was tested on standard target species (STS). Lycopersicon esculentum and Lactuca sativa were the most sensitive species in this test. A total of eleven compounds have been isolated and characterized. Compounds 1, 2, 4, and 6 have not been identified previously from O. pulchella and ocoteol (9) is reported for the first time in the literature. Eight compounds were tested on wheat coleoptile growth, and spathulenol, benzyl salicylate, and benzyl benzoate showed the highest activities. These compounds showed inhibitory activity on L. esculentum. The values obtained correspond to the activity exhibited by the extract and these compounds may therefore be responsible for the allelopathic activity shown by O. pulchella.

  12. Eragrostis plana Nees as a novel eco-friendly adsorbent for removal of crystal violet from aqueous solutions.

    PubMed

    Filho, Augusto Cezar D; Mazzocato, Ana C; Dotto, Guilherme L; Thue, Pascal S; Pavan, Flávio A

    2017-07-08

    Eragrostis plana Nees (EPN) was used as new and eco-friendly adsorbent for the removal of crystal violet dye (CV) from aqueous solution. Specific surface area (BET), scanning electron microscopy (SEM), infrared spectroscopy (ATR-FTIR), point of zero charge (pHPZC), and modified Boehm titration method were used to characterize the EPN material. The effects of initial pH of solution, adsorbent mass, contact time and initial dye concentration, and temperature were studied in batch adsorption mode. Kinetic data were evaluated by pseudo-first-order and pseudo-second-order models. The result exhibited that pseudo-second-order model well described the adsorption kinetics of CV onto EPN. Langmuir, Freundlich, and Sips isotherm models were used for analysis of the isothermal data. The equilibrium data of adsorption of CV onto EPN was better fitted with the Sips isotherm. Based on the Sips isotherm model, the maximum adsorption capacity was 76.20 ± 1.20 mg g(-1) at 333 K. A high desorption of CV from EPN was obtained using 1.00 mol L(-1) of CH3COOH as eluent. The thermodynamic data indicated that the adsorption was spontaneous, endothermic, and physical process. EPN can be used as alternative adsorbent to remove CV from aqueous solution.

  13. Aporphine alkaloids from the leaves of Phoebe grandis (Nees) Mer. (Lauraceae) and their cytotoxic and antibacterial activities.

    PubMed

    Omar, Hanita; Hashim, Najihah Mohd; Zajmi, Asdren; Nordin, Noraziah; Abdelwahab, Siddiq Ibrahim; Azizan, Ainnul Hamidah Syahadah; Hadi, A Hamid A; Ali, Hapipah Mohd

    2013-07-29

    The oxoaporphine alkaloid lysicamine (1), and three proaporphine alkaloids, litsericinone (2), 8,9,11,12-tetrahydromecambrine (3) and hexahydromecambrine A (4) were isolated from the leaves of Phoebe grandis (Nees) Merr. (Lauraceae). Compounds 2 and 3 were first time isolated as new naturally occurring compounds from plants. The NMR data for the compounds 2-4 have never been reported so far. Compounds 1 and 2 showed significant cytotoxic activity against a MCF7 (human estrogen receptor (ER+) positive breast cancer) cell line with IC₅₀ values of 26 and 60 µg/mL, respectively. Furthermore, in vitro cytotoxic activity against HepG2 (human liver cancer) cell line was evaluated for compounds 1-4 with IC₅₀ values of 27, 14, 81 and 20 µg/mL, respectively. Lysicamine (1) displayed strong antibacterial activity against Bacillus subtilis (B145), Staphylococcus aureus (S1434) and Staphylococus epidermidis (a clinically isolated strain) with inhibition zones of 15.50 ± 0.57, 13.33 ± 0.57 and 12.00 ± 0.00 mm, respectively. However, none of the tested pathogenic bacteria were susceptible towards compounds 2 and 3.

  14. Pharmacokinetic and Pharmacodynamic Interaction of Andrographolide and Standardized Extract of Andrographis paniculata (Nees) with Nabumetone in Wistar Rats.

    PubMed

    Balap, Aishwarya; Lohidasan, Sathiyanarayanan; Sinnathambi, Arulmozhi; Mahadik, Kakasaheb

    2017-01-01

    The aim of the study was to investigate the herb-drug interaction of Andrographis paniculata Nees (Acanthaceae) and Andrographolide (AN) with nabumetone (NAB) in wistar rats. Pharmacokinetic and pharmacodynamic interactions were studied after co-administration of APE and AN with NAB in Wistar rats. In pharmacokinetic studies, significant decrease in Cmax, AUC0-t and AUC0-∞ of 6-MNA after co-administration with pure AN and APE has been observed. Tmax of 6-MNA has been increased to 2 h from 1.5 h in AN + NAB treated group. Changes in mean residential time, clearance and volume of distribution of 6-MNA in APE + NAB treated group and AN + NAB treated group indicated interference of other components of APE other than AN. In pharmacodynamic study, significant decrease in antiarthritic activity of NAB on concomitant administration with APE and AN has been observed. The study concludes that NAB exhibits pharmacokinetic and pharmacodynamic interactions with APE and AN in rats thus alarms the concomitant use of herbal preparations containing APE and AN with NAB. Further study is needed to understand the mechanism and predict the herb-drug interaction in humans. Copyright © 2016 John Wiley & Sons, Ltd.

  15. Light, Soil Temperature, and VPD as controls of flux-tower NEE partitioning into gross photosynthesis and respiration in grassland and agricultural ecosystems

    NASA Astrophysics Data System (ADS)

    Gilmanov, T. G.

    2010-12-01

    Partitioning of the flux-tower net CO2 exchange measurements (NEE) into gross photosynthesis (Pg) and ecosystem respiration (Re) components is an essential step in post-processing flux tower data for analysis and modeling. We have developed a method of NEE = Pg - Re partitioning using photosynthetically active radiation (Q), soil temperature at 5 cm depth (Ts), and vapor pressure deficit at 2 m height (VPD) as factors in a nonrectangular hyperbolic model of net CO2 exchange in terrestrial ecosystems (Gilmanov et al. 2003, Bas. Appl. Ecol. 4: 167-183) modified to include the effect of vapor pressure deficit. In contrast to other VPD-based methods of NEE partitioning suggested in the literature, our method (i) describes combined effect of VPD on photosynthetic capacity (Amax) and apparent quantum yield (ALPHA) due to the special functional properties of the nonrectangular hyperbolic equation; (ii) delivers less biased estimates of light-response parameters due to explicit description of the convexity of the light-response compared to rectangular hyperbolic model, and (iii) generates more numerically robust and statistically significant estimates than methods using highly correlated predictors such as incoming radiation, air temperature and VPD. We demonstrate application of the method to flux-tower NEE data sets from grassland and agro-ecosystems of North America as a tool to estimate numerical values and uncertainty characteristics of productivity, respiration, and ecophysiological parameters (apparent quantum yield ALPHA, photosynthetic capacity Amax, gross ecological light-use efficiency LUE, carbon use efficiency CUE, and others). On a representative statistical material our results confirm earlier findings that gross photosynthesis estimates derived through partitioning of flux-tower NEE are significantly closer related to remote sensing indices (e.g., eMODIS NDVI) than variables directly provided by tower measurements such as day-time net CO2 flux totals. We

  16. Protective activity of andrographolide and arabinogalactan proteins from Andrographis paniculata Nees. against ethanol-induced toxicity in mice.

    PubMed

    Singha, Prajjal K; Roy, Somenath; Dey, Satyahari

    2007-04-20

    To find out the active principles against ethanol-induced toxicity in mice, Andrographis paniculata Nees. (Ap) was chosen and isolated andrographolide (ANDRO) and arabinogalactan proteins (AGPs). ANDRO was detected by HPTLC, FTIR and quantified by HPLC (10mg/g of Ap powder). AGPs was detected by beta-glucosyl Yariv staining of SDS-PAGE gel, FTIR and quantified by single radial gel diffusion assay with beta-glucosyl Yariv reagent (0.5mg/g Ap powder). The mice are pretreated intra-peritoneally (i.p.) with different doses (62.5, 125, 250, and 500mg/kg) of body weight of mice] of ANDRO and AGPs for 7 days and then ethanol (7.5g/kg of body weight) was injected, i.p. Besides, silymarin was used as standard hepatoprotective agent for comparative study with ANDRO and AGPs. The ameliorative activity of ANDRO and AGP against hepatic renal alcohol toxicity was measured by assessing GOT, GPT, ACP, ALP and LP levels in liver and kidney. It has been observed that pretreatment of mice with ANDRO and AGPs at 500mg/kg of body weight and 125mg/kg of body weight respectively could able to minimize the toxicity in compare to ethanol treated group as revealed by the different enzymatic assay in liver and kidney tissues and the results were comparable with silymarin. Hence, out of several ill-defined compounds present in Ap, ANDRO and AGPs are the potential bioactive compounds responsible for protection against ethanol-induced toxicity.

  17. Coupling of Pore Pressure and Ground Motion: Further Studies using Data Recorded at the NEES@UCSB Wildlife Station

    NASA Astrophysics Data System (ADS)

    Seale, S. H.; Lavallee, D.; Archuleta, R. J.; Steidl, J. H.

    2012-12-01

    Pore pressure built up during an earthquake and the hazard associated with soil liquefaction present a major challenge for our society, as has been dramatically illustrated by recent large events (e.g. the 2011 Tohoku-oki, Japan, earthquake). There is consensus among scientists that a better assessment of the liquefaction risk requires a better understanding of the coupling between pore pressure and ground motion time histories. There is a basic need to investigate coupling as a function of the frequency content of the ground motion. The 2010 M7.2 El Mayor-Cucapah event has provided a remarkable opportunity to investigate and model the coupling. The event was well recorded at the NEES@UCSB Wildlife station located 110 km from the hypocenter. The station is equipped with three-component strong-motion accelerometers at the surface and in boreholes at various depths and with pore pressure transducers located in a saturated, liquefiable layer. The recorded pore pressure and ground motion time histories both have frequency content that is a function of time. We have applied a wavelet decomposition technique to the El Mayor ground motion and pore pressure data, looking for a linear relationship between the signals. The analysis shows that the early P-wave accelerations (vertical component) initiate pore pressure response. However, the pore pressure records contain a low-frequency component that dominates the signal with no corresponding low-frequency component in the ground motion signals recorded near-by. Although uncommon, a similar behavior has been also reported in the literature for pore pressure signals recoded during the 1980 Mammoth Lakes, California, earthquake. We have extended this work to the analysis of 4 other seismic events that have induced an increase in pore pressure at WLA. As the response of pore pressure is potentially a local phenomenon, we have restricted our analysis to recordings from the same site. These events include the M5.8 Ocotillo

  18. Three new 7.3',8.5'-connected bicyclo[3.2.1]octanoids and other neolignans from leaves of Nectandra amazonum NEES. (Lauraceae).

    PubMed

    Coy Barrera, Ericsson David; Cuca Suárez, Luis Enrique

    2009-06-01

    Three new 7.3',8.5'-connected (macrophyllin-type) bicyclo[3.2.1]octanoid neolignans (nectamazins A-C, 1-3) were isolated from leaves of Nectandra amazonum NEES., along with seven known neolignans (4-10). The structures of 1-3 were characterized by spectroscopic methods (1D, 2D NMR) and the absolute configuration was assigned on the basis of circular dichroism (CD) spectra supported by nuclear Overhauser effect spectroscopy (NOESY) correlations. The new compounds showed inhibition activity against platelet activating factor (PAF)-induced aggregation of rabbit platelets.

  19. Seasonal and Inter-Annual Patterns in Ecosystem-Scale Photosynthesis and Respiration in a Temperate Forest Revealed by Isotopic Partitioning of NEE

    NASA Astrophysics Data System (ADS)

    Wehr, R. A.; Munger, J. W.; McManus, J. B.; Nelson, D. D.; Zahniser, M. S.; Wofsy, S. C.; Saleska, S. R.

    2014-12-01

    Measurements of the isotopic composition of the net ecosystem-atmosphere exchange of CO2 (NEE) can be used to partition that exchange into its photosynthetic and respiratory components on an hourly basis, without the need for a priori assumptions about the responses of those components to environmental drivers. This method relies on photosynthesis and respiration having distinct isotopic signatures, which they generally do because the photosynthetic signature varies hourly (e.g. with light availability), whereas the respiratory signature is governed mostly by soil substrate composition and so varies only daily or weekly. Since 2011, we have been measuring the isotopic composition of NEE in a temperate deciduous forest by eddy covariance, using a quantum cascade laser spectrometer. Previously presented isotopic partitioning of the 2011 growing season indicated that ecosystem photosynthesis became more efficient through the summer (with respect to light and water use) and that during the hot, dry period in July, daytime ecosystem respiration was more strongly limited by soil moisture than was nighttime respiration, leading standard non-isotopic partitioning to substantially overestimate daytime ecosystem respiration and hence photosynthesis. Here we extend our analysis to span the three-year period from 2011 through 2013, taking advantage of large inter-annual differences in the seasonal pattern of soil moisture at the forest to test the prediction that standard partitioning exaggerates daytime ecosystem respiration and photosynthesis under drought conditions, and to further explore the mechanisms behind the apparent increase in photosynthetic efficiency through the summer.

  20. The effects of Andrographis paniculata (Burm.f.) Nees extract and diterpenoids on the CYP450 isoforms' activities, a review of possible herb-drug interaction risks.

    PubMed

    Tan, Mei Lan; Lim, Lin Ee

    2015-01-01

    Andrographis paniculata (Burm.f.) Nees is a popular medicinal plant and its components are used in various traditional product preparations. However, its herb-drug interactions risks remain unclear. This review specifically discusses the various published studies carried out to evaluate the effects of Andrographis paniculata (Burm.f.) Nees plant extracts and diterpenoids on the CYP450 metabolic enzyme and if the plant components pose a possible herb-drug interaction risk. Unfortunately, the current data are insufficient to indicate if the extracts or diterpenoids can be labeled as in vitro CYP1A2, CYP2C9 or CYP3A4 inhibitors. A complete CYP inhibition assay utilizing human liver microsomes and the derivation of relevant parameters to predict herb-drug interaction risks may be necessary for these isoforms. However, based on the current studies, none of the extracts and diterpenoids exhibited CYP450 induction activity in human hepatocytes or human-derived cell lines. It is crucial that a well-defined experimental design is needed to make a meaningful herb-drug interaction prediction.

  1. Long-term impacts of peatland restoration on the net ecosystem exchange (NEE) of blanket bogs in Northern Scotland.

    NASA Astrophysics Data System (ADS)

    Hambley, Graham; Hill, Timothy; Saunders, Matthew; Arn Teh, Yit

    2016-04-01

    Unmanaged peatlands represent an important long-term C sink and thus play an important part of the global C cycle. Despite covering only 12 % of the UK land area, peatlands are estimated to store approximately 20 times more carbon than the UK's forests, which cover 13% of the land area. The Flow Country of Northern Scotland is the largest area of contiguous blanket bog in the UK, and one of the biggest in Europe, covering an area in excess of 4000 km2 and plays a key role in mediating regional atmospheric exchanges of greenhouse gases (GHGs) such as carbon dioxide (CO2), and water vapour (H2O). However, these peatlands underwent significant afforestation in the 1980s, when over 670 km2 of blanket bog were drained and planted with Sitka spruce (Picea sitchensis) and Lodgepole pine (Pinus contorta). This resulted in modifications to hydrology, micro-topography, vegetation and soil properties all of which are known to influence the production, emission and sequestration of key GHGs. Since the late 1990s restoration work has been carried out to remove forest plantations and raise water tables, by drain blocking, to encourage the recolonisation of Sphagnum species and restore ecosystem functioning. Here, we report findings of NEE and its constituent fluxes, GPP and Reco, from a study investigating the impacts of restoration on C dynamics over a chronosequence of restored peatlands. The research explored the role of environmental variables and microtopography in modulating land-atmosphere exchanges, using a multi-scale sampling approach that incorporated eddy covariance measurements with dynamic flux chambers. Key age classes sampled included an undrained peatland; an older restored peatland (17 years old); and a more recently restored site (12 years old). The oldest restored site showed the strongest uptake of C, with an annual assimilation rate of 858 g C m-2 yr-1 compared to assimilation rates of 501g C m-2 yr-1 and 575g C m-2 yr-1 from the younger restored site and

  2. Anti-Infective Metabolites of a Newly Isolated Bacillus thuringiensis KL1 Associated with Kalmegh (Andrographis paniculata Nees.), a Traditional Medicinal Herb

    PubMed Central

    Roy, Sudipta; Yasmin, Sahana; Ghosh, Subhadeep; Bhattacharya, Somesankar; Banerjee, Debdulal

    2016-01-01

    This study was conducted to isolate endophytic bacteria possessing anti-infective property from Kalmegh (Andrographis paniculata Nees.), a well-known medicinal plant. A total of 23 strains were isolated from this plant among which the strain KL1, isolated from surface-sterilized leaf of this medicinal herb, showed broad-spectrum antagonism against an array of Gram-positive and -negative bacterial pathogens. Ethyl acetate extract of KL1-fermented media yielded a greenish amorphous substance retaining anti-infective property. Solvent-extracted crude material was separated by thin-layer chromatography, and the active ingredient was located by autobiogram analysis. The purified anti-infective compound was found as anthracene derivative as analyzed by ultraviolet and Fourier transform infrared spectroscopy. The strain was identified as Bacillus thuringiensis KL1 from cultural, physiochemical, and molecular aspects. The above results indicate the pharmaceutical potential of the candidate isolate. PMID:26997870

  3. Does Casing Material Influence Downhole Accelerometer Recordings? a Controlled Study of Earthquake and Experimental Data Recorded at the NEES@UCSB Wildlife Liquefaction Array

    NASA Astrophysics Data System (ADS)

    Huthsing, D. A.; Seale, S. H.; Steidl, J. H.; Ratzesberger, H.; Hegarty, P.; Nees@Ucsb

    2010-12-01

    In 2004, NEES@UCSB outfitted the Wildlife Liquefaction Array (WLA) with new instrumentation and initiated an experiment to test whether casing material influences downhole recordings of strong ground motion. Two 5.5m boreholes were drilled meters apart. One of the boreholes was cased with traditional rigid PVC and the other with flexible Corex® drain pipe. Three-component strong-motion accelerometers were installed in both boreholes. Recently we have obtained a unique set of data at WLA that has allowed us to conduct a controlled study. On 15 June 2010, a Mw 5.7 event occurred near Ocotillo, CA, 57 km SW from WLA. A set of 60 aftershocks with M > 3.0 were recorded at WLA with good signal-to-noise ratio. These data are ideal for our study, as the events are approximately co-located relative to the site and they have similar focal mechanisms. We computed frequency spectra for the three components of motion for these events and we computed average spectral ratios between the data in the two boreholes. The spectral ratios are not flat ( = 1): certain frequencies within the range of engineering interest ( f < 20 Hz) recorded in the flexible borehole show amplification and damping relative to the recordings from the rigid borehole. An amplification factor of 1.4 is the maximum in this frequency range. In May 2010, NEES@UTexas visited WLA with the vibroseis truck T-Rex. We have performed spectral analysis of borehole recordings from 30 T-Rex pulses with frequencies ranging from 3 to 16 Hz. We present these spectral ratios for comparison with the ones computed from earthquake data.

  4. Protective Effect of Adhatoda vascia Nees Against Radiation-Induced Damage at Cellular, Biochemical and Chromosomal Levels in Swiss Albino Mice

    PubMed Central

    Samarth, Ravindra; Kumar, Madhu; Selvan, Senthamil R.; Saharan, Begraj; Kumar, Ashok

    2007-01-01

    Extract of Adhatoda vasica (L) Nees leaves has been used for treatment of various diseases and disorders in Ayurved and Unani medicine. Modulatory effect of ethanolic extract of A. vasica (L) Nees against radiation-induced changes in terms of histological alterations in testis, reduced glutathione (GSH), lipid peroxidation (LPO), acid and alkaline phosphatases levels, and chromosomal alterations in Swiss albino mice was studied at various post-irradiation intervals between 1 and 30 days. Mice exposed to 8 Gy radiation showed radiation-induced sickness including marked changes in histology of testis and chromosomal aberrations in bone marrow cells with 100% mortality within 22 days. When ethanolic leaf extract of A. vasica was given orally at a dose of 800 mg kg−1 body weight per mouse for 15 consecutive days and then exposed to radiation, death of Adhatoda-pretreated irradiated mice was reduced to 70% at 30 days. The radiation dose reduction factor was 1.43. There was significantly lesser degree of damage to testis tissue architecture and various cell populations including spermatogonia, spermatids and Leydig cells. Correspondingly, a significant decrease in the LPO and an increase in the GSH levels were observed in testis and liver of Adhatoda-pretreated irradiated mice. Similarly, a significant decrease in level of acid phosphatase and increase in level of alkaline phosphatase were observed. Adhatoda pretreatment significantly prevented radiation-induced chromosomal damage in bone marrow cells. The study suggests that Adhatoda plant extract has significant radioprotective effects on testis that warrants further mechanistic studies aimed at identifying the role of major ingredients in the extract. PMID:17965765

  5. Anxiolytic-like effects of (O-methyl)-N-2,6-dihydroxybenzoyl-tyramine (riparin III) from Aniba riparia (Nees) Mez (Lauraceae) in mice.

    PubMed

    de Melo, Carla Thiciane Vasconcelos; Monteiro, Andreisa Paiva; Leite, Caroline Porto; de Araújo, Fernando Luiz Oliveira; Lima, Vera Targino Moreira; Barbosa-Filho, José Maria; de França Fonteles, Marta Maria; de Vasconcelos, Silvânia Maria Mendes; de Barros Viana, Glauce Socorro; de Sousa, Francisca Cléa Florenço

    2006-03-01

    This work presents behavioral effects of (O-methyl)-N-2,6-dihydroxybenzoyl-tyramine (riparin III) isolated from the unripe fruit of Aniba riparia (Nees) Mez (Lauraceae) in animal models of open field, rota rod, elevated plus maze and hole board tests in mice. Riparin III (ripIII) was administered orally, in male mice, at single doses of 25 and 50 mg/kg. The results showed that ripIII, at both doses, had no effects on the spontaneous motor activity in the rota rod test nor in the number of squares crossed in the open field test. However, riparin III decreased the number of grooming and rearing. In the plus maze test, ripIII, at both doses increased the following parameters: percentage of entries in the open arms (PEOA), time of permanence in the open arms (TPOA) and percentage of time of permanence in the open arms (PTOA) and at the dose of 50 mg/kg, increased the number of entries in the open arms (NEOA). Similarly, ripIII, at both doses, showed an increase in the number of head dips into the holes of the hole board test. These results show that riparin III presents anxiolytic effects in the plus maze and hole board tests which are not influenced by the locomotor activity in the open field test.

  6. Evaluation of effects of N-(2-hydroxybenzoyl) tyramine (riparin II) from Aniba riparia (NEES) MEZ (Lauracea) in anxiety models in mice.

    PubMed

    de Sousa, Francisca Cléa Florenço; Leite, Caroline Porto; de Melo, Carla Thiciane Vasconcelos; de Araújo, Fernando Luiz Oliveira; Gutierrez, Stanley Juan Chavez; Barbosa-Filho, José Maria; Fonteles, Marta Maria de França; de Vasconcelos, Silvânia Maria Mendes; de Barros Viana, Glauce Socorro

    2007-07-01

    In order to evaluate the effects produced by N-(2-hydroxybenzoyl) tyramine (riparin II) isolated from the unripe fruit of Aniba riparia (NEES) MEZ (Lauraceae) on the central nervous system, different behavioral tests were performed. Riparin II (rip II) was administered orally (p.o.) and intraperitoneally (i.p.) in male mice, at doses of 25, 50 and 75 mg/kg, and tested on elevated plus maze (EPM), open field, rota rod and hole board tests. The results revealed that rip II caused considered increase of the number of head dips in hole board test and increased the number of entries and the time of permanence in the open arms in plus maze test in both routes. No significant effect was evidenced on rota rod and open field test, except an increase observed in the number of rearing. These results showed that riparin II presents anxiolytic-like effects in the plus maze and hole board tests which are not influenced by the locomotor activity as detected in the open field test.

  7. Dehydroandrographolide, an iNOS inhibitor, extracted from Andrographis paniculata (Burm.f.) Nees, induces autophagy in human oral cancer cells.

    PubMed

    Hsieh, Ming-Ju; Lin, Chiao-Wen; Chiou, Hui-Ling; Yang, Shun-Fa; Chen, Mu-Kuan

    2015-10-13

    Autophagy, which is constitutively executed at the basal level in all cells, promotes cellular homeostasis by regulating the turnover of organelles and proteins. Andrographolide and dehydroandrographolide (DA) are the two principle components of Andrographis paniculata (Burm.f.) Nees. and are the main contributors to its therapeutic properties. However, the pharmacological activities of dehydroandrographolide (DA) remain unclear. In this study, DA induces oral cancer cell death by activating autophagy. Treatment with autophagy inhibitors inhibited DA-induced human oral cancer cell death. In addition, DA increased LC3-II expression and reduced p53 expression in a time- and concentration-dependent manner. Furthermore, DA induced autophagy and decreased cell viability through modulation of p53 expression. DA-induced autophagy was triggered by an activation of JNK1/2 and an inhibition of Akt and p38. In conclusion, this study demonstrated that DA induced autophagy in human oral cancer cells by modulating p53 expression, activating JNK1/2, and inhibiting Akt and p38. Finally, an administration of DA effectively suppressed the tumor formation in the oral carcinoma xenograft model in vivo. This is the first study to reveal the novel function of DA in activating autophagy, suggesting that DA could serve as a new and potential chemopreventive agent for treating human oral cancer.

  8. Spectral Analysis of Pore Pressure Data Recorded from the 2010 Sierra EL Mayor (baja California) Earthquake at the NEES@UCSB Wildlife Field Site

    NASA Astrophysics Data System (ADS)

    Seale, S. H.; Lavallee, D.; Steidl, J. H.; Ratzesberger, H.; Hegarty, P.

    2010-12-01

    On 4 April 2010, the M7.2 Sierra el Mayor event occurred in Baja California, Mexico. The NEES@UCSB Wildlife field site in the Imperial Basin is located 110 km NNW of the hypocenter. The event was recorded on all channels: by three-component strong-motion accelerometers at the surface and in boreholes at various depths and by pore pressure transducers located in a saturated, liquefiable layer. We have computed the spectra of the pore pressure response in the frequency domain for signals recorded at different depths. At each depth, the spectrum is attenuated as a power law with a sharp discontinuity at a frequency close to 1 Hz. We report the value of the exponents that characterize the power-law behavior of these spectra. We also computed cross-spectral analysis of the pore pressure records from different depths. The functional behaviors of the curves of the cross-spectra are similar to that of the original spectra. For comparison, we present the spectrum of each component of the ground motion recorded at a nearby accelerometer. Partially due to the late arrival of the surface waves, the frequency content of the recorded pore pressure signal is a function of time. To gain a better understanding of the time-dependence of the frequency content, we performed spectral analysis of the signal in a moving window and wavelet transforms of the full signals. The spectral analysis suggests that, except for high frequencies, the curves exhibit a complex behavior as a function of the window position. We interpret and discuss the consequences of the estimated spectra, the cross-spectra, and the wavelet transforms.

  9. The anti-inflammatory effect of Andrographis paniculata (Burm. f.) Nees on pelvic inflammatory disease in rats through down-regulation of the NF-κB pathway.

    PubMed

    Zou, Wei; Xiao, Zuoqi; Wen, Xiaoke; Luo, Jieying; Chen, Shuqiong; Cheng, Zeneng; Xiang, Daxiong; Hu, Jian; He, Jingyu

    2016-11-25

    Andrographis paniculata (Burm. f.) Nees (APN), a principal constituent of a famous traditional Chinese medicine Fukeqianjin tablet which is used for the treatment of pelvic inflammatory disease (PID), has been reported to have anti-inflammatory effect in vitro. However, whether it has pharmacological effect on PID in vivo is unclear. Therefore, the aim of this study is to test the anti-inflammatory effect of APN and illuminate a potential mechanism. Thirty-six female specific pathogen-free SD rats were randomly divided into control group, PID group, APN1 group, APN2 group, APN3 group and prednisone group. Pathogen-induced PID rats were constructed. The APN1, APN2 and APN3 group rats were orally administrated with APN extract at different levels. The prednisone group rats were administrated with prednisone. Eight days after the first infection, the histological examination of upper genital tract was carried out, and enzyme-linked immunosorbent assay (ELISA) was carried out using homogenate of the uterus and fallopian tube. Furthermore, immunohistochemical evaluations of NF-κB p65 and IκB-α in uterus was conducted. APN obviously suppressed the infiltrations of neutrophils and lymphocytes, and it could significantly reduce the excessive production of cytokines and chemokines including IL-1β, IL-6, CXCL-1, MCP-1 and RANTES in a dose-dependent manner. Furthermore, APN could block the pathogen-induced activation of NF-κB pathway. APN showed potent anti-inflammatory effect on pathogen-induced PID in rats, with a potential mechanism of inhibiting the NF-κB signal pathway.

  10. Concurrent production and relative quantification of vasicinone from in vivo and in vitro plant parts of Malabar nut (Adhatoda vasica Nees).

    PubMed

    Panigrahi, Jitendriya; Gantait, Saikat; Patel, Illa C

    2017-10-01

    The present study documents a simultaneous production and comparative assessment of extracted vasicinone from in vivo (leaves and stems) and in vitro (leaves, stems and calli) plant parts of Adhatoda vasica Nees, a well-known medicinal plant. High-performance thin layer chromatography (HPTLC) analysis of the above-mentioned plant parts, collected at their 60-day-old growth stage, was performed via methanolic extraction and with the aid of toluene:butanol:butyl acetate (9:0.5:0.5; v/v/v) solvent system. The method was validated with the help of aluminium sheet precoated with silica gel 60 F254 TLC plates, following the ICH guidelines in order to maintain accuracy, precision and repeatability. Correlation coefficient, limit of detection and limit of quantification values were found to be reasonable. The outcome revealed a linearity that ranged between 2 and 6 µg/spot. During the comparison of estimated vasicinone quantity from in vivo and in vitro plant parts, it was evident that in vitro samples produced relatively higher vasicinone than that of the in vivo counterparts. Maximum vasicinone (6.402 ± 0.010% of dry weight) production was quantified from in vitro leaves followed by calli (5.222 ± 0.092% of dry weight) and in vitro stems (2.007 ± 0.041% of dry weight). On the other hand, in vivo leaves and stems produced comparatively lower quantities of vasicinone (2.412 ± 0.139 and 1.933 ± 0.046% of dry weight, respectively) suggesting the in vitro clonal propagation as a superior approach in comparison to in vivo propagation. Nonetheless, simultaneous production from both the sources (in vivo and in vitro plant parts) provides a new avenue for augmented production of vasicinone.

  11. Ho-Nee-Um Trail.

    ERIC Educational Resources Information Center

    Irwin, Harriet; And Others

    Appreciation and concern for the preservation of our natural resources by all citizens is the primary concern of this teacher's guide for use in the elementary grades. It employes the use of a filmstrip in conjunction with a local nature trail, to guide students in developing awareness - by looking closely, listening, touching, and smelling. Major…

  12. Hybrid analysis (barcode-high resolution melting) for authentication of Thai herbal products, Andrographis paniculata (Burm.f.) Wall.ex Nees

    PubMed Central

    Osathanunkul, Maslin; Suwannapoom, Chatmongkon; Khamyong, Nuttaluck; Pintakum, Danupol; Lamphun, Santisuk Na; Triwitayakorn, Kanokporn; Osathanunkul, Kitisak; Madesis, Panagiotis

    2016-01-01

    Background: Andrographis paniculata Nees is a medicinal plant with multiple pharmacological properties. It has been used over many centuries as a household remedy. A. paniculata products sold on the markets are in processed forms so it is difficult to authenticate. Therefore buying the herbal products poses a high-risk of acquiring counterfeited, substituted and/or adulterated products. Due to these issues, a reliable method to authenticate products is needed. Materials and Methods: High resolution melting analysis coupled with DNA barcoding (Bar-HRM) was applied to detect adulteration in commercial herbal products. The rbcL barcode was selected to use in primers design for HRM analysis to produce standard melting profile of A. paniculata species. DNA of the tested commercial products was isolated and their melting profiles were then generated and compared with the standard A. paniculata. Results: The melting profiles of the rbcL amplicons of the three closely related herbal species (A. paniculata, Acanthus ebracteatus and Rhinacanthus nasutus) are clearly separated so that they can be distinguished by the developed method. The method was then used to authenticate commercial herbal products. HRM curves of all 10 samples tested are similar to A. paniculata which indicated that all tested products were contained the correct species as labeled. Conclusion: The method described in this study has been proved to be useful in aiding identification and/or authenticating A. paniculata. This Bar-HRM analysis has allowed us easily to determine the A. paniculata species in herbal products on the markets even they are in processed forms. SUMMARY We propose the use of DNA barcoding combined with High Resolution Melting analysis for authenticating of Andrographis paniculata products.The developed method can be used regardless of the type of the DNA template (fresh or dried tissue, leaf, and stem).rbcL region was chosen for the analysis and work well with our samplesWe can easily

  13. Coupling of Pore Pressure and Ground Motion Data Recorded During the 2010 El Mayor-Cucapah (Baja California) Earthquake at the NEES@UCSB Wildlife Station

    NASA Astrophysics Data System (ADS)

    Lavallee, D.; Seale, S. H.; Steidl, J. H.

    2011-12-01

    Pore pressure built up during an earthquake and the hazard associated with soil liquefaction present a major challenge for our society, as was dramatically displayed during the 2011 Higashi Nihon Daishinsai (Tohoku-oki, Japan) earthquake. Currently, there is a consensus among scientists that a better assessment of the risk associated with liquefaction requires a better understanding of the coupling between pore pressure time histories and ground motion time histories. Specifically, there is a basic need to investigate the coupling as a function of the frequency content of the ground motion. The 2010 El Mayor-Cucapah (Baja California) earthquake (M 7.2) provides a remarkable opportunity to undertake such an investigation and lay the basis to model the coupling. The event was well recorded at the NEES@UCSB Wildlife station located 110 km from the hypocenter. The station is equipped with three-component strong-motion accelerometers at the surface and in boreholes at various depths and with pore pressure transducers located in a saturated, liquefiable layer. The recorded pore pressure and ground motion time histories are both characterized by a frequency content that is a function of time. A wavelet representation is a natural approach to investigate non-stationary time histories. To study the coupling between two signals we use the following procedure: We first compute the wavelet coefficients associated with the two signals. Then we compute the correlation between the wavelet coefficients of the two signals as a function of the frequency. Correlation coefficients provide information about the degree of linear dependence between the two signals. To account for the presence of multiplicative constants relating the wavelet coefficients of the first signal to the wavelet coefficients of the second signal, we compare the square norm of the wavelet coefficients of the two signals for the available frequency range. Additionally, investigating the distribution of the square

  14. Blood matrix effects for male and female Wistar rats, in simultaneous HPLC-UV determination of riparin I and III from Aniba riparia (Nees) Mez. (Lauraceae).

    PubMed

    dos Santos, Sócrates Golzio; Queiroga, Karine Formiga; de Oliveira, Adriana Maria Fernandes; Tavares, Josean Fechine; Gutierrez, Stanley Juan Chavez; Diniz, Margareth de Fátima Formiga Melo; Barbosa-Filho, José Maria; da Silva, Marcelo Sobral

    2011-10-30

    Aniba riparia (Nees) Mez. (Lauraceae) is popularly known as "louro", and is found in Amazonia and in the Guianas, its distribution extends to the Andes. Alkamide alkaloids were isolated from its green fruit; they were denominated riparin I (methyl ether of N-benzoyl tyramine), riparin II (methyl ether of N-2-hydroxy-benzoyl tyramine) and riparin III (methyl ether of N-2,6-dihydroxy-benzoyl tyramine) in tribute to the plant. When administered orally and intraperitoneally to mice, riparin I and III are anxiolytic, yet without any sedative or muscle relaxing effects. The present study shows that variables such as extraction solvent, centrifugation force, and centrifugation time, are important in the simultaneous liquid-liquid extraction of riparin I and III from male and female Wistar rat blood in HPLC-UV studies. The study confirms matrix influence on simultaneous recovery and detection of riparin I and III. The effect of rat blood matrix for riparin I was -13.86%, while for riparin III it was -10.94%. The recovery for riparin I was 82.14%, while for riparin III it was 87.42%. The efficiency of the process was 73.25% for riparin I and 77.81% for riparin III, demonstrating an optimal method for simultaneous recovery of riparins I and III from the blood of rats. The matrix effect for rat blood showed values of 10.25% for riparin I and -83.01% for riparin III. Recovery for riparin I was 113.11%, whereas for riparin III it was 13.65%. The process efficiency of this method for female rat blood was 125.88% for riparin I and 2.58% for riparin III. Simultaneous recovery of riparin I and III from the blood of male and female rats using acetonitrile as the precipitating solvent, while centrifuged at 10,000 × g for 10 min demonstrated the importance of the parameters chosen for the extraction/recovery process of different analytes. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. ED-XRF spectrometric analysis of comparative elemental composition of in vivo and in vitro roots of Andrographis paniculata (Burm.f.) Wall. ex Nees--a multi-medicinal herb.

    PubMed

    Behera, P R; Nayak, P; Barik, D P; Rautray, T R; Thirunavoukkarasu, M; Chand, P K

    2010-12-01

    The multi-elemental composition of in vitro--proliferated root tissues of Andrographis paniculata (Burm.f.) Wall. ex Nees was compared with that of the naturally grown in vivo plants. Trace elements namely Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Rb, Sr and Pb in addition to two macro-elements K and Ca were identified and quantified in root tissues of both sources using the energy dispersive X-ray fluorescence (ED-XRF) technique. ED-XRF analysis was performed using Mo K X-rays generated from a secondary molybdenum target. The elemental content of in vitro roots was found to be at par with that of naturally grown plants of the same species. This opens up a possibility of exploiting in vitro root cultures as a viable, alternative and renewable source of phytochemicals of relevance, besides providing a means for conservation of the valuable natural resources.

  16. Application of centrifugal precipitation chromatography and high-speed counter-current chromatography equipped with a spiral tubing support rotor for the isolation and partial characterization of carotenoid cleavage-like enzymes in Enteromorpha compressa (L.) Nees.

    PubMed

    Baldermann, Susanne; Mulyadi, Andriati N; Yang, Ziyin; Murata, Ariaka; Fleischmann, Peter; Winterhalter, Peter; Knight, Martha; Finn, Thomas M; Watanabe, Naoharu

    2011-10-01

    Centrifugal precipitation chromatography and a high-speed counter-current chromatography system equipped with a spiral tubing support rotor (spHSCCC) were successfully applied for the identification and isolation of carotenoid cleavage-like enzymes from Enteromorpha compressa (L.) Nees. This is the first study separating active enzymes from a complex natural matrix by spHSCCC. The target enzymes were identified after fractionation of the proteins in an acetone Tris-buffer gradient by centrifugal precipitation chromatography. Also, an aqueous two-phase solvent system consisting of PEG 1000 and mono- and dibasic potassium phosphate was used for the isolation of the enzymes by spHSCCC. The purified fractions contained two proteins of 65 and 72 kDa, respectively. The enzymes could cleave β-carotene and β-apo-8'-carotenal to produce β-ionone.

  17. Separation of five compounds from leaves of Andrographis paniculata (Burm. f.) Nees by off-line two-dimensional high-speed counter-current chromatography combined with gradient and recycling elution.

    PubMed

    Zhang, Li; Liu, Qi; Yu, Jingang; Zeng, Hualiang; Jiang, Shujing; Chen, Xiaoqing

    2015-05-01

    An off-line two-dimensional high-speed counter-current chromatography method combined with gradient and recycling elution mode was established to isolate terpenoids and flavones from the leaves of Andrographis paniculata (Burm. f.) Nees. By using the solvent systems composed of n-hexane/ethyl acetate/methanol/water with different volume ratios, five compounds including roseooside, 5,4'-dihydroxyflavonoid-7-O-β-d-pyranglucuronatebutylester, 7,8-dimethoxy-2'-hydroxy-5-O-β-d-glucopyranosyloxyflavon, 14-deoxyandrographiside, and andrographolide were successfully isolated. Purities of these isolated compounds were all over 95% as determined by high-performance liquid chromatography. Their structures were identified by UV, mass spectrometry, and (1) H NMR spectroscopy. It has been demonstrated that the combination of off-line two-dimensional high-speed counter-current chromatography with different elution modes is an efficient technique to isolate compounds from complex natural product extracts.

  18. Double-blind, placebo-controlled, randomized, pilot clinical trial of ImmunoGuard--a standardized fixed combination of Andrographis paniculata Nees, with Eleutherococcus senticosus Maxim, Schizandra chinensis Bail. and Glycyrrhiza glabra L. extracts in patients with Familial Mediterranean Fever.

    PubMed

    Amaryan, G; Astvatsatryan, V; Gabrielyan, E; Panossian, A; Panosyan, V; Wikman, G

    2003-05-01

    Double blind, randomized, placebo controlled pilot study of ImmunoGuard--a standardized fixed combination of Andrographis paniculata Nees., Eleutherococcus senticosus Maxim., Schizandra chinensis Bail., and Glycyrrhiza glabra L. special extracts standardized for the content of Andrographolide (4 mg/tablet), Eleuteroside E, Schisandrins and Glycyrrhizin, was carried out in two parallel groups of patients. The study was conducted in 24 (3-15 years of both genders) patients with Familial Mediterranean Fever (FMF), 14 were treated with tablets of series A (verum) and 10 patients received series B product (placebo). The study medication was taken three times of four tablets daily for 1 month. Daily dose of the andrographolide--48 mg. The primary outcome measures in physician's evaluation were related to duration, frequency and severity of attacks in FMF patients (attacks characteristics score). The patient's self-evaluation was based mainly on symptoms--abdominal, chest pains, temperature, arthritis, myalgia, erysipelas-like erythema. All of 3 features (duration, frequency, severity of attacks) showed significant improvement in the verum group as compared with the placebo. In both clinical and self evaluation the severity of attacks was found to show the most significant improvement in the verum group. Both the clinical and laboratory results of the present phase II (pilot) clinical study suggest that ImmunoGuard is a safe and efficacious herbal drug for the management of patients with FMF.

  19. A review on antidiabetic activity of Citrullus colocynthis Schrad.

    PubMed

    Shi, Chenghe; Karim, Sabiha; Wang, Chunyong; Zhao, Mingjing; Murtaza, Ghulam

    2014-01-01

    Current studies have elaborated diabetes mellitus as one of the most prevalent endocrine disorder throughout the world. Citrullus colocynthis (C. colocynthis) is one of the most common traditional plants used as remedy against diabetes mellitus. It is well recognized by its hypoglycemic effect, which is substantiated in current phytotherapy. Its undesired effects include the disturbance of gastrointestinal and urinary tracts. This review article encompasses various blood glucose lowering studies that have been carried out till date. Various parts of plants used in extract preparation were roots, fruits, seeds, rinds and leaves. The nature of these extracts was ethnolic, methanolic, or aqueous and their doses varied from 10 to 500 mg/kg body weight/day. All these published articles elaborate C. colocynthis as a potential antiglycemic medicinal plant.

  20. Cucurbitacins from the Leaves of Citrullus colocynthis (L.) Schrad.

    PubMed

    Chawech, Rachid; Jarraya, Raoudha; Girardi, Cynthia; Vansteelandt, Marieke; Marti, Guillaume; Nasri, Imen; Racaud-Sultan, Claire; Fabre, Nicolas

    2015-09-30

    Two new tetracyclic cucurbitane-type triterpene glycosides were isolated from an ethyl acetate extract of Citrullus colocynthis leaves together with four known cucurbitacins. Their structures were established on the basis of their spectroscopic data (mainly NMR and mass spectrometry). Evaluation of the in vitro cytotoxic activity of the isolated compounds against two human colon cancer cell lines (HT29 and Caco-2) and one normal rat intestine epithelial cell line (IEC6), revealed that one of the isolated compounds presented interesting specific cytotoxic activity towards colorectal cell lines.

  1. Fermi (nee GLAST) at Six Months

    NASA Technical Reports Server (NTRS)

    Ritz, Steve

    2009-01-01

    The Fermi Gamma-ray Space Telescope, formerly called GLAST, is a mission to measure the cosmic gamma-ray flux in the energy range 20 MeV to >300 GeV, with supporting measurements for gamma-ray bursts from 8 keV to 30 MeV. In addition to breakthrough capabilities in energy coverage and localization, the very large field of view enables observations of 20% of the sky at any instant, and the entire sky on a timescale of a few hours. With its recent launch on 11 June 2008, Fermi now opens a new and important window on a wide variety of phenomena, including pulsars, black holes and active galactic nuclei, gamma-ray bursts, the origin of cosmic rays and supernova remnants, and searches for hypothetical new phenomena such as supersymmetric dark matter annihilations. In addition to early results and the science opportunities, this talk includes a description of the instruments and the mission status and plans.

  2. Exploring Ho-Nee-Um in the Spring.

    ERIC Educational Resources Information Center

    Madison Public Schools, WI.

    Appreciation and concern for the preservation of our natural resources by all citizens is the primary concern of this teacher's guide for use in grades three and four. It employs the use of a filmstrip in conjunction with a local nature trail, to guide students in developing awareness--by looking closely, listening, touching, and smelling. The…

  3. A Winter Walk at Ho-Nee-Um.

    ERIC Educational Resources Information Center

    Irwin, Harriet; And Others

    Appreciation and concern for the preservation of our natural resources by all citizens is the primary concern of this teacher's guide for use in the lower primary grades. It employs the use of a filmstrip in conjunction with a local nature trail, to guide students in developing awareness - by looking closely, listening, touching, and smelling. The…

  4. Effect of bioactive fractions of Citrullus vulgaris Schrad. leaf extract against Anopheles stephensi and Aedes aegypti.

    PubMed

    Mullai, K; Jebanesan, A; Pushpanathan, T

    2008-04-01

    The benzene extract of Citrullus vulgaris was tested against Anopheles stephensi and Aedes aegypti for the larvicidal activity and ovicidal properties. The crude benzene extract was found to be more effective against A. stephensi than A. aegypti. The LC50 values were 18.56 and 42.76 ppm respectively. The LC50 values for silica gel fractions (bioactive fractions I, II, III and IV) were 11.32, 14.12, 14.53 and 16.02 ppm respectively. The mean per cent hatchability of the egg rafts were observed after 48 h post treatment. The crude extract of benzene exerted 100% mortality at 250 ppm against A. stephensi and at 300 ppm against A. aegypti. The silica gel fractions I and II afforded 100% mortality at 100 ppm and III and IV exerted the hatchability rate of 4.9 and 5.3% at the same concentration against A. stephensi.

  5. Biomedical potential of silver nanoparticles synthesized from calli cells of Citrullus colocynthis (L.) Schrad

    PubMed Central

    2011-01-01

    Background An increasingly common application is the use of silver nanoparticles for antimicrobial coatings, wound dressings, and biomedical devices. In this present investigation, we report, biomedical potential of silver nanopaticles synthesized from calli extract of Citrullus colocynthis on Human epidermoid larynx carcinoma (HEp -2) cell line. Methods The callus extract react with silver nitrate solution confirmed silver nanoparticles synthesis through the steady change of greenish colour to reddish brown and characterized by using FT-IR, AFM. Toxicity on HEp 2 cell line assessed using MTT assay, caspase -3 assay, Lactate dehydrogenase leakage assay and DNA fragmentation assay. Results The synthesized silver nanoparticles were generally found to be spherical in shape with size 31 nm by AFM. The molar concentration of the silver nanoparticles solution in our present study is 1100 nM/10 mL. The results exhibit that silver nanoparticles mediate a dose-dependent toxicity for the cell tested, and the silver nanoparticles at 500 nM decreased the viability of HEp 2 cells to 50% of the initial level. LDH activities found to be significantly elevated after 48 h of exposure in the medium containing silver nanoparticles when compared to the control and Caspase 3 activation suggested that silver nanoparticles caused cell death through apoptosis, which was further supported by cellular DNA fragmentation, showed that the silver nanoparticles treated HEp2 cells exhibited extensive double strand breaks, thereby yielding a ladder appearance (Lane 2), while the DNA of control HEp2 cells supplemented with 10% serum exhibited minimum breakage (Lane 1). This study revealed completely would eliminate the use of expensive drug for cancer treatment. PMID:21943321

  6. Oil and fatty acid contents in seed of Citrullus lanatus Schrad.

    PubMed

    Jarret, Robert L; Levy, Irvin J

    2012-05-23

    Intact seed of 475 genebank accessions of Citrullus ( C. lanatus var. lanatus and C. lanatus var. citroides) were analyzed for percent oil content using TD-NMR. Extracts from whole seed of 96 accessions of C. lanatus (30 var. citroides, 33 var. lanatus, and 33 egusi), C. colocynthis (n = 3), C. ecirrhosus (n = 1), C. rehmii (n = 1), and Benincasa fistulosa (n = 3) were also analyzed for their fatty acids content. Among the materials analyzed, seed oil content varied from 14.8 to 43.5%. Mean seed oil content in egusi types of C. lanatus was significantly higher (mean = 35.6%) than that of either var. lanatus (mean = 23.2%) or var. citroides (mean = 22.6%). Egusi types of C. lanatus had a significantly lower hull/kernel ratio when compared to other C. lanatus var. lanatus or C. lanatus var. citroides. The principal fatty acid in all C. lanatus materials examined was linoleic acid (43.6-73%). High levels of linoleic acid were also present in the materials of C. colocynthis (71%), C. ecirrhosus (62.7%), C. rehmii (75.8%), and B. fistulosa (73.2%), which were included for comparative purposes. Most all samples contained traces (<0.5%) of arachidonic acid. The data presented provide novel information on the range in oil content and variability in the concentrations of individual fatty acids present in a diverse array of C. lanatus, and its related species, germplasm.

  7. Biomedical potential of silver nanoparticles synthesized from calli cells of Citrullus colocynthis (L.) Schrad.

    PubMed

    Satyavani, K; Gurudeeban, S; Ramanathan, T; Balasubramanian, T

    2011-09-26

    An increasingly common application is the use of silver nanoparticles for antimicrobial coatings, wound dressings, and biomedical devices. In this present investigation, we report, biomedical potential of silver nanopaticles synthesized from calli extract of Citrullus colocynthis on Human epidermoid larynx carcinoma (HEp -2) cell line. The callus extract react with silver nitrate solution confirmed silver nanoparticles synthesis through the steady change of greenish colour to reddish brown and characterized by using FT-IR, AFM. Toxicity on HEp 2 cell line assessed using MTT assay, caspase -3 assay, Lactate dehydrogenase leakage assay and DNA fragmentation assay. The synthesized silver nanoparticles were generally found to be spherical in shape with size 31 nm by AFM. The molar concentration of the silver nanoparticles solution in our present study is 1100 nM/10 mL. The results exhibit that silver nanoparticles mediate a dose-dependent toxicity for the cell tested, and the silver nanoparticles at 500 nM decreased the viability of HEp 2 cells to 50% of the initial level. LDH activities found to be significantly elevated after 48 h of exposure in the medium containing silver nanoparticles when compared to the control and Caspase 3 activation suggested that silver nanoparticles caused cell death through apoptosis, which was further supported by cellular DNA fragmentation, showed that the silver nanoparticles treated HEp2 cells exhibited extensive double strand breaks, thereby yielding a ladder appearance (Lane 2), while the DNA of control HEp2 cells supplemented with 10% serum exhibited minimum breakage (Lane 1). This study revealed completely would eliminate the use of expensive drug for cancer treatment.

  8. Antinociceptive and anti-inflammatory effects of aqueous extract of Chenopodium opulifolium schrad leaves

    PubMed Central

    Ajayi, Abayomi M.; Tanayen, Julius Khidzee; Magomere, Albert; Ezeonwumelu, Joseph O. C.

    2017-01-01

    Aim: Chenopodium opulifolium is a specie of the Chenopodiaceae commonly used as vegetables in local diet and for treating different ailment in Uganda. This study was conducted to evaluate the antioxidant, antinociceptive and anti-inflammatory effects of the aqueous extract of C. opulifolium leaves (AECO). Materials and Methods: The dried leaf of the plant was extracted by maceration in water. Qualitative and quantitative phytochemical analysis, antioxidants, and membrane stabilizing effects were determined in the extract. The extract was then investigated for acute toxicity, antinociceptive (writhing, hot plate and open field test), and anti-inflammatory (egg albumin-induced paw edema) effects in rodents. Results: Phytochemical analysis revealed the presence of alkaloids, tannins, phlobatannins, flavonoids, and saponins in AECO. Total caffeic acid derivatives and total flavonoids content were 91.7 mgCAE/g sample and 94.7 mgRE/g sample, respectively. AECO demonstrated antioxidant effects in both 1,1-diphenyl-2-picryl-hydrazyl and NO assays. Significant membrane stabilizing activity was observed in both the heat and hypotonic solution-induced lysis of erythrocytes. The acute toxicity test showed that AECO (5000 mg/kg) did not cause any significant change in behavior or death in rats. AECO (100-400 mg/kg) produced a significant antinociceptive effect in both the writhing and hot plate tests, but no significant reduction in the locomotory activity in mice. Furthermore, the extract significantly (P < 0.05) reduced egg albumin-induced rat paw edema by 44.2%, 44.5%, and 51.2%, respectively, after 120 min. Conclusion: The results showed that C. opulifolium extract possesses significant antioxidant, antinociceptive and anti-inflammatory effects, and these affirm the reasons for its folkloric use. PMID:28163955

  9. Water uptake, priming, drying and storage effects in Cassia excelsa Schrad seeds.

    PubMed

    Jeller, H; Perez, S C; Raizer, J

    2003-02-01

    The aims of this study were to evaluate the effects of osmotic potential on the water uptake curve in Cassia excelsa seeds and use the results to analyze the effects of dehydration and storage on primed seed germination. Seeds were imbibed in distilled water and polyethylene glicol (PEG 6000) osmotic solutions at -0.2, -0.4, and -0.6 MPa, at 20 degrees C. The radicle emergence and seed moisture content were evaluated at 6-hour intervals during 240 hours. Afterwards, seeds were primed in distilled water and PEG 6000 solutions at -0.2, -0.4, and -0.6 MPa for 48, 72, 96, and 168 hours at 20 degrees C, followed by air drying and storage for 15 days at 5 degrees C. The lower the osmotic potential, the higher the time required for priming. The osmoconditioning yields benefits with PEG solutions at 0.0 and -0.2 MPa; seed improvements were maintained during storage for 15 days at 5 degrees C, but were reverted by seed drying.

  10. Antimycobacterial activity of Citrullus colocynthis (L.) Schrad. against drug sensitive and drug resistant Mycobacterium tuberculosis and MOTT clinical isolates.

    PubMed

    Mehta, Archana; Srivastva, Garima; Kachhwaha, Sumita; Sharma, Meenakshi; Kothari, S L

    2013-08-26

    Citrullus colocynthis (Cucurbitaceae), a folk herbal medicine and traditionally used natural remedy for tuberculosis in India has been studied to validate its antitubercular activity against drug sensitive and drug resistant (including multidrug resistant) Mycobacterium tuberculosis and Mycobacterium other than tuberculosis (MOTT) bacilli. Inhibitory and bactericidal activities of crude extracts, fractions and compounds of Citrullus colocynthis plant, consisting of aerial parts and ripe deseeded fruits were performed against the drug sensitive standard strain of Mycobacterium tuberculosis H37Rv (ATCC 27294), 16 drug resistant strains of Mycobacterium tuberculosis and two MOTT strains, using radiometric BACTEC 460TB system. Methanolic extract of ripe deseeded fruit of Citrullus colocynthis has shown good activity (MIC ≤ 62.5 µg/ml), whereas among the bioactive fractions, FC IX demonstrated the best activity (MIC 31.2 µg/ml) against Mycobacterium tuberculosis H37Rv. Bioactive FC III, IX and X also inhibited 16 clinical isolates of Mycobacterium tuberculosis consisting of seven non-multidrug resistants, eight multidrug resistants, one extensively drug resistant and two of MOTTs with MICs in the range of 50-125, 31.2-125 and 62.5-125 µg/ml, respectively. Ursolic acid and cucurbitacin E 2-0-β-d-glucopyranoside were identified as the main biomarkers active against Mycobacterium tuberculosis H37Rv (MICs 50 and 25 µg/ml respectively), as well as against the 18 clinical isolates. FC III and FC IX showed better inhibition of drug resistant and MOTT clinical isolates. Minimal bactericidal concentrations of extracts, fractions and compound C-2 were ≥ two-fold MIC values. The study provides a scientific rationale for the traditional use of Citrullus colocynthis fruit in the treatment of tuberculosis. In addition, the study elucidates a broad spectrum antimycobacterial action of Citrullus colocynthis fruit, which can contribute to the development of improved preparation of an antitubercular natural drug for the treatment of drug resistant tuberculosis and MOTT infection as well. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  11. High efficient somatic embryogenesis development from leaf cultures of Citrullus colocynthis (L.) Schrad for generating true type clones.

    PubMed

    Ramakrishna, D; Shasthree, T

    2016-04-01

    We report an efficient somatic embryogenesis and plant regeneration system using leaf cultures of Citrullus colocynthis (L.) and assessed the effect of plant growth regulators on the regeneration process. Initially leaf explants were cultured on Murashige and Skoog medium supplemented with different concentrations of auxins viz., 2,4-dichlorophenoxyacetic acid, 1-naphthaleneacetic acid, gibberellic acid alone and along with combination of 6-benzylaminopurine. The different forms of calli such as compact, white friable, creamy friable, brownish nodular, green globular and green calli were induced from the leaf explants on MS medium containing different concentrations of auxins and gibberellins. Subsequently initial callus was subcultured at 1.5 mg L(-1) BAP + 1.0 mg L(-1) 2,4-D which resulted in 25 % somatic embryos from 85 % nodular embryogenic nodular callus that is highest percentage. Similarly the lowest percentage of somatic embryos was recorded at 2.5 mg L(-1) BAP + 0.5 mg L(-1) NAA from 55 % embryogenic globular callus i.e., 16 %. High frequency of embryo development takes place at intermittent light when compared with continuous light in the individual subcultures. The cotyledonary embryos were developed into complete platelets on MS medium. In vitro regenerated plantlets were washed to remove the traces of agar and then transferred to sterile vermiculite and sand (2:1) containing pot.

  12. Transcriptome sequencing of a thalloid bryophyte; Dumortiera hirsuta (Sw) Nees: assembly, annotation, and marker discovery

    PubMed Central

    Singh, Harpal; Rai, Krishan Mohan; Upadhyay, Santosh Kumar; Pant, Poonam; Verma, Praveen Chandra; Singh, Ajit Pratap; Singh, Pradhyumna Kumar

    2015-01-01

    Bryophytes are the first land plants but are scarcely studied at the molecular level. Here, we report transcriptome sequencing and functional annotation of Dumortiera hirsuta, as a representative bryophyte. Approximately 0.5 million reads with ~195 Mb data were generated by sequencing of mRNA using 454 pyrosequencer. De novo assembly of reads yielded 85,240 unigenes (12,439 contigs and 72,801 singletons). BlastX search at NCBI-NR database showed similarity of 33,662 unigenes with 10-10 e-value. A total of 23,685 unigenes were annotated at TAIR10 protein database. The annotated unigenes were further classified using the Gene Ontology. Analysis at Kyoto Encyclopedia of Genes and Genomes pathway database identified 95 pathways with significant scores, among which metabolic and biosynthesis of secondary metabolite were the major ones. Phenylpropanoid pathway was elucidated and selected genes were characterized by real time qPCR. We identified 447 transcription factors belonging to 41 families and 1594 eSSRs in 1479 unigenes. D. hirsuta unigenes showed homology across the taxa from algae to angiosperm indicating their role as the connecting link between aquatic and terrestrial plants. This could be a valuable genomic resource for molecular and evolutionary studies. Further, it sheds light for the isolation and characterization of new genes with unique functions. PMID:26481431

  13. Neonicotinoid-induced resurgence of rice leaffolder, Cnaphalocrocis medinalis (Guénee).

    PubMed

    Chintalapati, Padmavathi; Katti, Gururaj; Puskur, Raghuveer Rao; Nagella Venkata, Krishnaiah

    2016-01-01

    Among the neonicotinoids, imidacloprid and thiamethoxam have been frequently used in planthopper endemic areas. Wherever leaffolder incidence occurs along with planthoppers in rice fields, use of neonicotinoids has resulted in increase in leaffolder population. The present study was carried out to verify and confirm the resurgence, as well as to identify factors contributing to resurgence. In imidacloprid- and thiamethoxam-applied plots, a 17.5-217.5% increase in leaffolder population over the untreated control was observed. Neonicotinoids showed moderate toxicity to eggs with <50% hatching, and less toxicity to first instars with >60% survival, while 37-60% of larvae reached adult stage. The larval duration was also reduced. Fecundity was stimulated, with a 6.2-37.21% increase over the untreated control. A significant positive correlation was observed between larval population and total soluble sugars in thiamethoxam treatment (r = 0.9984, P ≤ 0.01). Stimulated fecundity on neonicotinoid-sprayed plants, coupled with reduced larval duration and low egg toxicity, could be the major factors contributing to the upsurge of leaffolder. This study aids in cautioning farmers to be more vigilant while using imidacloprid and thiamethoxam, particularly in rice fields where leaffolder exists alongside planthoppers. © 2015 Society of Chemical Industry.

  14. Transcriptome sequencing of a thalloid bryophyte; Dumortiera hirsuta (Sw) Nees: assembly, annotation, and marker discovery.

    PubMed

    Singh, Harpal; Rai, Krishan Mohan; Upadhyay, Santosh Kumar; Pant, Poonam; Verma, Praveen Chandra; Singh, Ajit Pratap; Singh, Pradhyumna Kumar

    2015-10-20

    Bryophytes are the first land plants but are scarcely studied at the molecular level. Here, we report transcriptome sequencing and functional annotation of Dumortiera hirsuta, as a representative bryophyte. Approximately 0.5 million reads with ~195 Mb data were generated by sequencing of mRNA using 454 pyrosequencer. De novo assembly of reads yielded 85,240 unigenes (12,439 contigs and 72,801 singletons). BlastX search at NCBI-NR database showed similarity of 33,662 unigenes with 10-(10) e-value. A total of 23,685 unigenes were annotated at TAIR10 protein database. The annotated unigenes were further classified using the Gene Ontology. Analysis at Kyoto Encyclopedia of Genes and Genomes pathway database identified 95 pathways with significant scores, among which metabolic and biosynthesis of secondary metabolite were the major ones. Phenylpropanoid pathway was elucidated and selected genes were characterized by real time qPCR. We identified 447 transcription factors belonging to 41 families and 1594 eSSRs in 1479 unigenes. D. hirsuta unigenes showed homology across the taxa from algae to angiosperm indicating their role as the connecting link between aquatic and terrestrial plants. This could be a valuable genomic resource for molecular and evolutionary studies. Further, it sheds light for the isolation and characterization of new genes with unique functions.

  15. Piptochaetium fuscum (Nees ex Steud.) Barkworth, Ciald., & Gandhi, a new combination replacing Piptochaetium setosum (Trin.) Arechav.

    PubMed Central

    Barkworth, Mary E.; Cialdella, Ana María; Gandhi, Kanchi

    2014-01-01

    Abstract A new name, Piptochaetium fuscum, is provided for a taxon hitherto known as Piptochaetium setosum (Trin.) Arechav. Morphological, anatomical, and molecular studies that argue against including Piptochaetium in Stipa, and hence use of S. purpurata (Phil.) Columbus & J.P. Sm., are cited. PMID:24843286

  16. [Principles and Methods for Formulating National Standards of "Regulations of Acupuncture-nee- dle Manipulating techniques"].

    PubMed

    Gang, Wei-juan; Wang, Xin; Wang, Fang; Dong, Guo-feng; Wu, Xiao-dong

    2015-08-01

    The national standard of "Regulations of Acupuncture-needle Manipulating Techniques" is one of the national Criteria of Acupuncturology for which a total of 22 items have been already established. In the process of formulation, a series of common and specific problems have been met. In the present paper, the authors expound these problems from 3 aspects, namely principles for formulation, methods for formulating criteria, and considerations about some problems. The formulating principles include selection and regulations of principles for technique classification and technique-related key factors. The main methods for formulating criteria are 1) taking the literature as the theoretical foundation, 2) taking the clinical practice as the supporting evidence, and 3) taking the expounded suggestions or conclusions through peer review.

  17. Intraspecific Crossability in Andrographis paniculata Nees: A Barrier against Breeding of the Species

    PubMed Central

    Valdiani, Alireza; Abdul Kadir, Mihdzar; Said Saad, Mohd; Talei, Daryush; Omidvar, Vahid; Hua, Chia Sok

    2012-01-01

    The ambiguity of crossability in Andrographis paniculata (AP) was pointed out in the present research. Accordingly, the effects of different style length and crossing time on intraspecific crossability of seven AP accessions in 21 possible combinations were investigated. The best results came out between 08:00 to 11:00 h for manual out-crossing of AP, while the time from 12:00 to 18:00 h showed a decreasing trend. Moreover, 12 mm style length was found as the most proper phenological stage in terms of stigmatic receptivity to perform out-crossing in this plant. All in all, AP behaved unlikely in each combination, and a significant difference was observed in crossability of AP accessions (P < 0.01). The lowest and highest crossability rate was found in hybrids 21 (11261NS × 11344K) and 27 (11322PA × 11350T) with 0.25% and 13.33%, respectively. Furthermore, a significant negative relationship between style length and crossibility (r2 = 0.762∗∗) was recorded in this research. As a final conclusion, crossing time and proper style length can improve the intraspecific crossability in the species, considerably. Despite all the mentioned contrivances, we still believe that a genetic incongruity should be involved as an additional obstacle in crossability of those combinations that failed or responded deficiently to outcrossing. PMID:22701352

  18. Piptochaetium fuscum (Nees ex Steud.) Barkworth, Ciald., & Gandhi, a new combination replacing Piptochaetium setosum (Trin.) Arechav.

    PubMed

    Barkworth, Mary E; Cialdella, Ana María; Gandhi, Kanchi

    2014-01-01

    A new name, Piptochaetium fuscum, is provided for a taxon hitherto known as Piptochaetium setosum (Trin.) Arechav. Morphological, anatomical, and molecular studies that argue against including Piptochaetium in Stipa, and hence use of S. purpurata (Phil.) Columbus & J.P. Sm., are cited.

  19. Phytostabilisation potential of lemon grass (Cymbopogon flexuosus (Nees ex Stend) Wats) on iron ore tailings.

    PubMed

    Mohanty, M; Dhal, N K; Patra, P; Das, B; Reddy, P S R

    2012-01-01

    The present pot culture study was carried out for the potential phytostabilisation of iron ore tailings using lemon grass (Cymbopogon flexuosus) a drought tolerant, perennial, aromatic grass. Experiments have been conducted by varying the composition of garden soil (control) with iron ore tailings. The various parameters, viz. growth of plants, number of tillers, biomass and oil content of lemon grass are evaluated. The studies have indicated that growth parameters of lemon grass in 1:1 composition of garden soil and iron ore tailings are significantly more (-5% increase) compared to plants grown in control soil. However, the oil content of lemon grass in both the cases more or less remained same. The results also infer that at higher proportion of tailings the yield of biomass decreases. The studies indicate that lemongrass with its fibrous root system is proved to be an efficient soil binder by preventing soil erosion.

  20. Antianxiety and antidepressant effects of riparin III from Aniba riparia (Nees) Mez (Lauraceae) in mice.

    PubMed

    Sousa, F C F; Melo, C T V; Monteiro, A P; Lima, V T M; Gutierrez, S J C; Pereira, B A; Barbosa-Filho, J M; Vasconcelos, S M M; Fonteles, M F; Viana, G S B

    2004-05-01

    This work presents behavioral effects of methyl ethers of N-(2,6-dihydroxybenzoyl) tyramine (riparin III) isolated from the unripe fruit of Aniba riparia on the open field, elevated plus maze (EPM), rotarod, hole board, barbiturate-induced sleeping time, tail suspension and forced swimming tests in mice. Riparin III was administered intraperitoneally to male mice at single doses of 25 and 50 mg/kg. The results showed that riparin III with both doses had no effects on spontaneous motor activity in mice or in the rotarod test, but decreased the number of grooming and rearing. At the dose of 50 mg/kg, riparin III increased the number of entries in the open arms of the EPM test as compared with control. Similarly, in the hole-board test, both doses increased the number of head dips. There was a reduction on the sleeping latency with both doses and a prolongation of the pentobarbital-induced sleeping time with the dose of 25 mg/kg. In the tail suspension test, similar to imipramine (30 mg/kg), riparin III at the dose of 50 mg/kg presented a reduction in the immobility time. In the forced swimming test, both doses of riparin III decreased the immobility time. These results showed that riparin III potentiated the barbiturate-induced sleeping time and presented antidepressant- and anxiolytic-like effects.

  1. Antianxiety effects of riparin I from Aniba riparia (Nees) Mez (Lauraceae) in mice.

    PubMed

    de Sousa, Francisca Cléa Florenço; Monteiro, Andreisa Paiva; de Melo, Carla Thiciane Vasconcelos; de Oliveira, Glício Rebouças; Vasconcelos, Silvânia Maria Mendes; de França Fonteles, Marta Maria; Gutierrez, Stanley Juan Chavez; Barbosa-Filho, José Maria; Viana, Glauce Socorro Barros

    2005-12-01

    This work presents the behavioral effects of riparin I (methyl ether of N-benzoyl tyramine) from unripe fruit of Aniba riparia (Lauraceae) on the elevated plus maze, open field, rota rod and hole board tests in mice. Riparin I was administered acutely by intraperitoneal (i.p.) and oral routes to male mice at doses of 25 and 50 mg/kg. The results showed that riparin I (25 and 50 mg/kg, i.p. and per os) increased the number of entries and the time of permanence in the open arms in the plus maze test. Similarly, in the hole board test, riparin I in both routes increased the number of head dips. Riparin I with both doses and routes had no effects on spontaneous motor activity in mice or in the rota rod test, but decreased the number of groomings. These results showed that riparin I by both administration routes has effects on the central nervous system with antianxiety effects on the plus maze and hole board tests. The substance is devoid of myorelaxant effects. Copyright 2005 John Wiley & Sons, Ltd.

  2. Amauroderma rugosum (Blume & T. Nees) Torrend: Nutritional Composition and Antioxidant and Potential Anti-Inflammatory Properties

    PubMed Central

    Chan, Pui-Mun; Kanagasabapathy, Gowri; Tan, Yee-Shin; Sabaratnam, Vikineswary; Kuppusamy, Umah Rani

    2013-01-01

    Amauroderma rugosum is a wild mushroom that is worn as a necklace by the indigenous communities in Malaysia to prevent fits and incessant crying by babies. The aim of this study was to investigate the nutritive composition and antioxidant potential and anti-inflammatory effects of A. rugosum extracts on LPS-stimulated RAW264.7 cells. Nutritional analysis of freeze-dried mycelia of A. rugosum (KUM 61131) from submerged culture indicated a predominant presence of carbohydrates, proteins, dietary fibre, phosphorus, potassium, and sodium. The ethanol crude extract (EE), its hexane (HF), ethyl acetate (EAF), and aqueous (AF) fractions of mycelia of A. rugosum grown in submerged culture were evaluated for antioxidant potential and anti-inflammatory effects. EAF exhibited the highest total phenolic content and the strongest antioxidant activity based on 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays. HF showed dose-dependent inhibition of NO production in LPS-stimulated RAW264.7 cells and NO radical scavenging activity. Gas chromatographic analysis of HF revealed the presence of ethyl linoleate and ergosterol, compounds with known anti-inflammatory properties. In conclusion, the nutritive compositions and significant antioxidant potential and anti-inflammatory effects of mycelia extracts of A. rugosum have the potential to serve as a therapeutic agent or adjuvant in the management of inflammatory disorders. PMID:24371454

  3. In vitro culture of immature embryos of Cinnamomum tamala Nees.--the role of different factors.

    PubMed

    Deb, Madhabi S; Jamir, N S; Deb, Chitta Ranjan

    2014-10-01

    Seed characteristics and in vitro culture of C. tamala embryos were studied. Embryos desiccated below 50% (fresh weight) exhibited poor morphogenetic response in vitro and confirmed the recalcitrant nature of seeds. The immature embryos of various developmental ages (4-16 week after flowering, WAF) were cultured on different strengths of MS medium. Morphogenesis responses were recorded after 10 days of culture. The best culture responses were achieved from the immature embryos of 12 WAF on MS medium with sucrose (3%, w/v), polyvinyl pyrollidone (100 mg L(-1)) and benzyl adenine (12 microM). Under optimum condition -60% explants responded; and -7.3 shoots buds developed per explants after 35 days of culture initiation. The shoot buds could be converted into micro-shoots on MS medium with sucrose (3%) and kinetin (3 microM). About 5.3 micro-shoots/shoot buds sprouted per sub-culture. The micro-shoots were rooted by maintaining them on MS medium with alpha-naphthalene acetic acid (3 microM) where within 6-8 wk of culture -8-10 roots developed. The rooted plantlets were acclimatized in vitro before they were transferred to community potting mix and maintained in the poly-shade ca 75% shading. The transplants registered -70% survival after two months of transfer.

  4. Analysis of the anticancer phytochemicals in Andrographis paniculata Nees. under salinity stress.

    PubMed

    Talei, Daryush; Valdiani, Alireza; Maziah, Mahmood; Sagineedu, Sreenivasa Rao; Saad, Mohd Said

    2013-01-01

    Salinity causes the adverse effects in all physiological processes of plants. The present study aimed to investigate the potential of salt stress to enhance the accumulation of the anticancer phytochemicals in Andrographis paniculata accessions. For this purpose, 70-day-old plants were grown in different salinity levels (0.18, 4, 8, 12, and 16 dSm(-1)) on sand medium. After inducing a period of 30-day salinity stress and before flowering, all plants were harvested and the data on morphological traits, proline content and the three anticancer phytochemicals, including andrographolide (AG), neoandrographolide (NAG), and 14-deoxy-11,12-didehydroandrographolide (DDAG), were measured. The results indicated that salinity had a significant effect on the aforementioned three anticancer phytochemicals. In addition, the salt tolerance index (STI) was significantly decreased, while, except for DDAG, the content of proline, the AG, and NAG was significantly increased (P ≤ 0.01). Furthermore, it was revealed that significant differences among accessions could happen based on the total dry weight, STI, AG, and NAG. Finally, we noticed that the salinity at 12 dSm(-1) led to the maximum increase in the quantities of AG, NAG, and DDAG. In other words, under salinity stress, the tolerant accessions were capable of accumulating the higher amounts of proline, AG, and NAG than the sensitive accessions.

  5. Andrographis paniculata (Burm. f.) Wall. ex Nees: a review of ethnobotany, phytochemistry, and pharmacology.

    PubMed

    Hossain, Md Sanower; Urbi, Zannat; Sule, Abubakar; Hafizur Rahman, K M

    2014-01-01

    As aboriginal sources of medications, medicinal plants are used from the ancient times. Andrographis paniculata is one of the highly used potential medicinal plants in the world. This plant is traditionally used for the treatment of common cold, diarrhoea, fever due to several infective cause, jaundice, as a health tonic for the liver and cardiovascular health, and as an antioxidant. It is also used to improve sexual dysfunctions and serve as a contraceptive. All parts of this plant are used to extract the active phytochemicals, but the compositions of phytoconstituents widely differ from one part to another and with place, season, and time of harvest. Our extensive data mining of the phytoconstituents revealed more than 55 ent-labdane diterpenoids, 30 flavonoids, 8 quinic acids, 4 xanthones, and 5 rare noriridoids. In this review, we selected only those compounds that pharmacology has already reported. Finally we focused on around 46 compounds for further discussion. We also discussed ethnobotany of this plant briefly. Recommendations addressing extraction process, tissue culture, and adventitious rooting techniques and propagation under abiotic stress conditions for improvement of phytoconstituents are discussed concisely in this paper. Further study areas on pharmacology are also proposed where needed.

  6. A classical genetic solution to enhance the biosynthesis of anticancer phytochemicals in Andrographis paniculata Nees.

    PubMed

    Valdiani, Alireza; Talei, Daryush; Tan, Soon Guan; Abdul Kadir, Mihdzar; Maziah, Mahmood; Rafii, Mohd Yusop; Sagineedu, Sreenivasa Rao

    2014-01-01

    Andrographolides, the diterpene lactones, are major bioactive phytochemicals which could be found in different parts of the medicinal herb Andrographis paniculata. A number of such compounds namely andrographolide (AG), neoandrographolide (NAG), and 14-deoxy-11,12-didehydroandrographolide (DDAG) have already attracted a great deal of attention due to their potential therapeutic effects in hard-to-treat diseases such as cancers and HIV. Recently, they have also been considered as substrates for the discovery of novel pharmaceutical compounds. Nevertheless, there is still a huge gap in knowledge on the genetic pattern of the biosynthesis of these bioactive compounds. Hence, the present study aimed to investigate the genetic mechanisms controlling the biosynthesis of these phytochemicals using a diallel analysis. The high performance liquid chromatography analysis of the three andrographolides in 210 F1 progenies confirmed that the biosynthesis of these andrographolides was considerably increased via intraspecific hybridization. The results revealed high, moderate and low heterosis for DDAG, AG and NAG, respectively. Furthermore, the preponderance of non-additive gene actions was affirmed in the enhancement of the three andrographolides contents. The consequence of this type of gene action was the occurrence of high broad-sense and low narrow-sense heritabilities for the above mentioned andrographolides. The prevalence of non-additive gene action suggests the suitability of heterosis breeding and hybrid seed production as a preferred option to produce new plant varieties with higher andrographolide contents using the wild accessions of A. paniculata. Moreover, from an evolutionary point of view, the occurrence of population bottlenecks in the Malaysian accessions of A. paniculata was unveiled by observing a low level of additive genetic variance (VA ) for all the andrographolides.

  7. Amauroderma rugosum (Blume & T. Nees) Torrend: Nutritional Composition and Antioxidant and Potential Anti-Inflammatory Properties.

    PubMed

    Chan, Pui-Mun; Kanagasabapathy, Gowri; Tan, Yee-Shin; Sabaratnam, Vikineswary; Kuppusamy, Umah Rani

    2013-01-01

    Amauroderma rugosum is a wild mushroom that is worn as a necklace by the indigenous communities in Malaysia to prevent fits and incessant crying by babies. The aim of this study was to investigate the nutritive composition and antioxidant potential and anti-inflammatory effects of A. rugosum extracts on LPS-stimulated RAW264.7 cells. Nutritional analysis of freeze-dried mycelia of A. rugosum (KUM 61131) from submerged culture indicated a predominant presence of carbohydrates, proteins, dietary fibre, phosphorus, potassium, and sodium. The ethanol crude extract (EE), its hexane (HF), ethyl acetate (EAF), and aqueous (AF) fractions of mycelia of A. rugosum grown in submerged culture were evaluated for antioxidant potential and anti-inflammatory effects. EAF exhibited the highest total phenolic content and the strongest antioxidant activity based on 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays. HF showed dose-dependent inhibition of NO production in LPS-stimulated RAW264.7 cells and NO radical scavenging activity. Gas chromatographic analysis of HF revealed the presence of ethyl linoleate and ergosterol, compounds with known anti-inflammatory properties. In conclusion, the nutritive compositions and significant antioxidant potential and anti-inflammatory effects of mycelia extracts of A. rugosum have the potential to serve as a therapeutic agent or adjuvant in the management of inflammatory disorders.

  8. Andrographis paniculata (Burm. f.) Wall. ex Nees: A Review of Ethnobotany, Phytochemistry, and Pharmacology

    PubMed Central

    Sule, Abubakar; Rahman, K. M. Hafizur

    2014-01-01

    As aboriginal sources of medications, medicinal plants are used from the ancient times. Andrographis paniculata is one of the highly used potential medicinal plants in the world. This plant is traditionally used for the treatment of common cold, diarrhoea, fever due to several infective cause, jaundice, as a health tonic for the liver and cardiovascular health, and as an antioxidant. It is also used to improve sexual dysfunctions and serve as a contraceptive. All parts of this plant are used to extract the active phytochemicals, but the compositions of phytoconstituents widely differ from one part to another and with place, season, and time of harvest. Our extensive data mining of the phytoconstituents revealed more than 55 ent-labdane diterpenoids, 30 flavonoids, 8 quinic acids, 4 xanthones, and 5 rare noriridoids. In this review, we selected only those compounds that pharmacology has already reported. Finally we focused on around 46 compounds for further discussion. We also discussed ethnobotany of this plant briefly. Recommendations addressing extraction process, tissue culture, and adventitious rooting techniques and propagation under abiotic stress conditions for improvement of phytoconstituents are discussed concisely in this paper. Further study areas on pharmacology are also proposed where needed. PMID:25950015

  9. A Classical Genetic Solution to Enhance the Biosynthesis of Anticancer Phytochemicals in Andrographis paniculata Nees

    PubMed Central

    Talei, Daryush; Abdul Kadir, Mihdzar; Rafii, Mohd Yusop; Sagineedu, Sreenivasa Rao

    2014-01-01

    Andrographolides, the diterpene lactones, are major bioactive phytochemicals which could be found in different parts of the medicinal herb Andrographis paniculata. A number of such compounds namely andrographolide (AG), neoandrographolide (NAG), and 14-deoxy-11,12-didehydroandrographolide (DDAG) have already attracted a great deal of attention due to their potential therapeutic effects in hard-to-treat diseases such as cancers and HIV. Recently, they have also been considered as substrates for the discovery of novel pharmaceutical compounds. Nevertheless, there is still a huge gap in knowledge on the genetic pattern of the biosynthesis of these bioactive compounds. Hence, the present study aimed to investigate the genetic mechanisms controlling the biosynthesis of these phytochemicals using a diallel analysis. The high performance liquid chromatography analysis of the three andrographolides in 210 F1 progenies confirmed that the biosynthesis of these andrographolides was considerably increased via intraspecific hybridization. The results revealed high, moderate and low heterosis for DDAG, AG and NAG, respectively. Furthermore, the preponderance of non-additive gene actions was affirmed in the enhancement of the three andrographolides contents. The consequence of this type of gene action was the occurrence of high broad-sense and low narrow-sense heritabilities for the above mentioned andrographolides. The prevalence of non-additive gene action suggests the suitability of heterosis breeding and hybrid seed production as a preferred option to produce new plant varieties with higher andrographolide contents using the wild accessions of A. paniculata. Moreover, from an evolutionary point of view, the occurrence of population bottlenecks in the Malaysian accessions of A. paniculata was unveiled by observing a low level of additive genetic variance (VA) for all the andrographolides. PMID:24586262

  10. Antiurolithiatic activity of saponin rich fraction from the fruits of Solanum xanthocarpum Schrad. & Wendl. (Solanaceae) against ethylene glycol induced urolithiasis in rats.

    PubMed

    Patel, Paras K; Patel, Manish A; Vyas, Bhavin A; Shah, Dinesh R; Gandhi, Tejal R

    2012-10-31

    A well-known traditional herb Solanum xanthocarpum is widely used in India for the management of different ailments including urolithiasis. This study was designed to rationalize the use of Solanum xanthocarpum in kidney stone and to investigate its mechanism of action. The saponin rich fraction prepared from fruits of Solanum xanthocarpum (SXS) was evaluated for antiurolithiatic activity by in vitro and in vivo studies. In ethylene glycol (EG, 0.75% in drinking water for 28 days) induced urolithiasis model, two different experimental doses (20 mg/kg and 40 mg/kg, p.o., for 28 days) of saponin rich fraction were selected by dose fixation study. After 28 days, various biochemical parameters were measured in urine, serum and kidney homogenate. Kidneys were also subjected to histopathological analysis. In vitro calcium oxalate crystal (CaOx) nucleation as well as aggregation was inhibited in artificial urine solution by SXS. The lithogenic treatment caused polyuria, damage renal function and oxidative stress, manifested as increased malondialdehyde, depleted reduced glutathione and decreased antioxidant enzyme catalase activities of the kidneys, which were prevented by simultaneous administration with SXS. Lithogenic treatment also caused crystalluria, hyperoxaluria, hypercalciuria, hypocitrauria, and hypomagnesaemia. Deposition of CaOx in renal tissue and cellular injury were seen in histopathology. Co-administration of SXS had potential to prevent these pathological changes due to lithogenic treatment. Moreover, SXS raised level of glycosaminoglycan, a stone inhibitor macromolecule found in urine which decreased. The antiurolithiatic activity in Solanum xanthocarpum is mediated possibly through the inhibition of CaOx crystal formation and its effect on the urinary concentration of stone-forming constituents and nephrolithiasis inducing factors and this study rationalizes its medicinal use in urolithiasis. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  11. Revegetation on a coal fine ash disposal site in South Africa

    SciTech Connect

    Van Rensburg, L.; De Sousa Correia, R.I.; Booysen, J.; Ginster, M.

    1998-11-01

    Eight medium amendments were conducted on top of a fine ash coal dump (i) to evaluate a few cost-effective treatments that could determine the minimum fertility status required for the local ash to support the establishment of a viable vegetation cover, and (ii) to select suitable grass species that would establish on the ash and could serve as a foundation for long-term rehabilitation. Degree and success of grass establishment per medium amelioration treatment is expressed in terms of total biomass, percentage basal cover, and in terms of a condition assessment model. Both the chemical and physical nature of the ash medium before and after amendment was characterized, as were the concentrations of some essential and potentially toxic elements in leaf samples. In terms of medium amelioration 5000 kg ha{sup {minus}1} compost, or 500 kg ha{sup {minus}1} kraal manure or 480 kg 2:3:2 ha{sup {minus}1} proved to be most effective. The grass species that occurred with the highest frequency, irrespective of treatment, were the perennials bermudagrass [Cynodon dactylon (L.) pers. var dactylon], weeping lovegrass [Eragrostis curvula (Schrader) Nees], and the annual teff [Eragrostis tef (Zuccagni) Trotter]. Of the potentially toxic extractable metals monitored in the leaves of vegetation on the dump, only Se accumulated to an average level of 4.4 mg kg{sup {minus}1} that could be toxic to livestock.

  12. In vitro flowering--a system for tracking floral organ development in Dendrocalamus hamiltonii Nees et Arn. ex Munro.

    PubMed

    Kaur, Devinder; Thapa, Pooja; Sharma, Madhu; Bhattacharya, Amita; Sood, Anil

    2014-08-01

    Dendrocalamus hamiltonii plants are slender and tall (15-25 m) thereby, rendering tagging, sampling and tracking the development of flowers difficult. Therefore, a reproducible system of in vitro flowering was established for tracking the stages of flower development. MS medium supplemented with 2.22 microM 6-benzylaminopurine, 1.23 microM indole-3-butyric acid and 2% sucrose was optimized as the flower induction medium (FIM) wherein 28 and 42 days were required for the development of gynoecium and androecium, respectively. Six distinct stages of in vitro flower development were identified, and the flowers were comparable with that of in planta sporadic flowers. Pollen viability of the in vitro flowers was higher than those of in planta ones. The in vitro system developed in the present study facilitates easy tracking of different stages of flower development under controlled environmental conditions. It can also be used for medium- or long-term storage of pollens and manipulation of in vitro fertilization.

  13. Endo- and ectomycorrhizas in Quercus agrifolia Nee. (Fagaceae): patterns of root colonization and effects on seedling growth.

    PubMed

    Egerton-Warburton, L; Allen, M F

    2001-12-01

    We documented the patterns of root occupancy by Glomalean and ectomycorrhizal (EM) fungi in Quercus agrifolia, and host plant responses to inoculation with each mycorrhizal type alone or in combination. Glomalean hyphae, coils and vesicles, and EM root tips were recorded. Colonization patterns conformed to a succession from Glomalean and EM fungi in 1-year-old seedlings to predominantly EM in saplings (>11 years old); both mycorrhizal types were rarely detected within the same root segment. Inoculation of Q. agrifolia seedlings with EM or Glomalean fungi (AM) alone or in combination (EM+AM) altered the cost:benefit relationship of mycorrhizas to the host plant. Seedling survival, plant biomass, foliar nitrogen (N), and phosphorus (P) status were greatest in EM- or AM-only inoculated seedlings. Seedlings inoculated with both mycorrhizal types (AM+EM) exhibited the lowest survival rates, biomass, foliar N, and P levels. Roots of these plants were highly colonized by both EM (38% root length colonized) and Glomalean fungi (34%). Because these levels of colonization were similar to those detected in 1-year-old field seedlings, the presence of both mycorrhizal types may be a carbon cost and, in turn, less beneficial to oaks during establishment in the field. However, the shift to EM colonization in older plants suggests that mycorrhizal effects may become positive with time.

  14. Proteomic Analysis of the Salt-Responsive Leaf and Root Proteins in the Anticancer Plant Andrographis paniculata Nees

    PubMed Central

    Rafii, Mohd Yusop; Maziah, Mahmood

    2014-01-01

    Separation of proteins based on the physicochemical properties with different molecular weight and isoelectric points would be more accurate. In the current research, the 45-day-old seedlings were treated with 0 (control) and 12 dS m−1 of sodium chloride in the hydroponic system. After 15 days of salt exposure, the total protein of the fresh leaves and roots was extracted and analyzed using two-dimensional electrophoresis system (2-DE). The analysis led to the detection of 32 induced proteins (19 proteins in leaf and 13 proteins in the root) as well as 12 upregulated proteins (four proteins in leaf and eight proteins in the root) in the salt-treated plants. Of the 44 detected proteins, 12 were sequenced, and three of them matched with superoxide dismutase, ascorbate peroxidase and ribulose-1, 5-bisphosphate oxygenase whereas the rest remained unknown. The three known proteins associate with plants response to environmental stresses and could represent the general stress proteins in the present study too. In addition, the proteomic feedback of different accessions of A. paniculata to salt stress can potentially be used to breed salt-tolerant varieties of the herb. PMID:25423252

  15. Road systems, land use, and related patterns of valley oak (Quercus lobata Nee) populations, seedling recruitment, and herbivory

    NASA Astrophysics Data System (ADS)

    Kuhn, Bill Ahlering

    This research investigates the interactions of road systems and land use on the population dynamics and recruitment of a long-lived tree in Mediterranean climate California. In the case of Valley oak (Quercus lobata), habitat conversion and limited recruitment of new individuals has resulted in widespread declines throughout Santa Barbara County and California. This pattern contrasts with high recruitment rates along roadsides, offering a unique opportunity to examine the effects of roads on the population dynamics of a native species. The pattern of roadside recruits is described, mapped, and a complete survey of the biophysical environment along 109 kilometers of road was conducted. The biophysical factors of the road and road system were of four types: (1) the general roadside environment; (2) the acorn supply; (3) a measure of ungulate deterrence; and, (4) roadside management. Seven individual or aggregate factors were then related to the pattern of seedling and sapling densities along roads. Univariate analysis and regression trees determined that acorn supply and total woody cover within the roadside plots explained 49% of the variation in Valley oak seedling densities. These results support the conclusion that the recruitment pattern is due to the roadsides serving as refugia from browsers (cattle and deer). The change in Valley oak populations within roadsides, croplands, rangelands, and urban/suburban lands over a 59 year period is examined using georeferenced aerial photos from 1938 and 1997. While population per capita growth rates were less than one (declining) within both rangelands and croplands, rates were greater than one (increasing) in urban/suburban populations. While roadside growth rates were even higher than those in urban/suburban areas, high variance resulted in a rate neither positive nor negative. Finally, seedlings were planted along roadsides and within adjacent grazed and ungrazed uplands to test browsing pressure. Seedlings within roadsides experienced significantly less browsing than those within the adjacent lands, lending support to the theory that roadsides provide refugia from browsing for Valley oak. Results are important for a deeper understanding of the causes and consequences of human land use and for assisting in the management of Valley oak and others similarly affected.

  16. Anxiolytic, antidepressant, and antistress activities of the aqueous extract of Cinnamomum tamala Nees and Eberm in rats

    PubMed Central

    Upadhyay, Gayaprasad; Khoshla, Sarvesh; Kosuru, Ramoji; Singh, Sanjay

    2016-01-01

    Objective: The current study was designed to explore anxiolytic, antidepressant, and antistress actions of Cinnamomum tamala (CT) leaves (aqueous extract) in rats. Materials and Methods: Behavioral procedures of anxiety, depression, and stress were assessed in rats. CT (100, 200, and 400 mg/kg) was given once a daily for 7 days via oral route and the efficacy was matched by those elicited by lorazepam (1 mg/kg, p.o.), imipramine (10 mg/kg, p.o.), and Withania somnifera (100 mg/kg, p.o.) for anxiolytic, antidepressant, and antistress studies, respectively. Standard drugs were given 1 time, 30 min preceding the behavioral trials. Results: One-way analysis of variance followed by Newman–Keuls multiple comparison test was employed to analyze the results. P < 0.05 was considered statistically significant as compared to control. CT at 400 mg/kg produced an antianxiety effect equivalent to lorazepam, in the elevated plus maze, open field, and social interaction tests among selected doses of the CT. CT at 400 mg/kg also induced an antidepressant activity similar to imipramine, in the behavioral despair, learned helplessness test, and tail suspension among selected doses of the CT. Moreover, CT at 400 mg/kg produced a significant antistress effect comparable to W. somnifera in water immersion-restraint stress by decreasing ulcer index, adrenal gland weight, and by normalizing the plasma levels of corticosterone, glucose, cholesterol, and triglyceride levels when related to stress control. Conclusion: The study shows that among the different CT doses, CT at 400 mg/kg possesses significant anxiolytic, antidepressant, and anti-stress effects and has therapeutic beneficial for the management of psychological ailments. PMID:27721543

  17. Antinociceptive effects of (O-methyl)-N-benzoyl tyramine (riparin I) from Aniba riparia (Nees) Mez (Lauraceae) in mice.

    PubMed

    Araújo, F L O; Melo, C T V; Rocha, N F M; Moura, B A; Leite, C P; Amaral, J F; Barbosa-Filho, J M; Gutierrez, S J C; Vasconcelos, S M M; Viana, G S B; de Sousa, Francisca Cléa Florenço

    2009-10-01

    The present study examined the antinociceptive effects of (O-methyl) N-benzoyl-tyramine (riparin I, ripI) isolated from the unripe fruit of Aniba riparia in chemical and thermal behavioral models of pain, such as acetic acid-induced abdominal writhing, formalin, and hot-plate tests in mice. Moreover, the involvement of the nitric oxide pathway as well as the opioid system in the antinociceptive action of ripI in the formalin test was investigated. RipI was administered both orally and intraperitoneally to male mice at single doses of 25 and 50 mg/kg. In the acetic acid-induced abdominal writhing, ripI decreased the number of writhings at both doses. In addition, in the formalin test, ripI reduced the paw licking time at both phases of the test. The effect of the highest dose of ripI in mice formalin test on the early phase was not reversed by naloxone (opioid receptor antagonist) but it was reversed by l-arginine (a nitric oxide precursor) in the late phase, suggesting that ripI may not act through opioid system and possibly acts through inhibition of nitric oxide pathway. In the hot-plate test, ripI increased the reaction time in the hot-plate test at the dose of 25 mg/kg, i.p., confirming the result found in the formalin test. Based on the obtained results, it is suggested that ripI presents antinociceptive activity that may be due to peripheral mechanisms (nitric oxide pathway) and central mechanisms, discarding the involvement of opioid system.

  18. In vitro acaricide activity of Ocotea aciphylla (Nees) Mez. (Lauraceae) extracts and identification of the compounds from the active fractions.

    PubMed

    Souza Conceição, Rodrigo; de A Carneiro, Monique Marylin A; Alves Reis, Isabella Mary; Branco, Alexsandro; Curcino Vieira, Ivo Jose; Braz-Filho, Raimundo; Borges Botura, Mariana

    2017-02-01

    The in vitro acaricide activity of hexane, ethyl acetate and ethanol extracts of Ocotea aciphylla leaves was investigated by means of an immersion tests using Rhipicephalus (Boophilus) microplus engorged females and larvae. All extracts were shown effective against the different stages of the parasite, and the ethanol extract (50mg/mL concentration) was the most active (more than 90% efficacy in both assays). The ethanolic extract was fractionated using column chromatography with silica gel as stationary phase to furnish several fractions that were tested against larvae of R. (B.) microplus. Three fractions showed high acaricidal activity (50mg/mL), causing between 84.2% and 100% mortality of the larvae. The anticholinesterase effect of these fractions was determined spectrophotometrically using a microtiter assay. The chemical investigation of the active fractions led to the characterization of terpenoids (cadalene 1 and squalene 2), a phenylpropanoid (dillapiole 3) and a phenolic mixture containing five proanthocyanidins (4-8) and a flavonoid(vitexin-2"-O-rhamnoside 9). Our findings suggest that the O. aciphylla has potent acaricidal activity in vitro against R. (B.) microplus, and that different secondary metabolites are responsible for this effect. Copyright © 2016 Elsevier GmbH. All rights reserved.

  19. An efficient in vitro regeneration protocol for a natural dye yielding plant, Strobilanthes flaccidifolious Nees., from nodal explants.

    PubMed

    Deb, Chitta Ranjan; Arenmongla, T

    2012-11-01

    Adventitious shoot buds formation from axillary buds of nodal segments of S. flaccidifolious was achieved on MS medium containing sucrose (3%, w/v), and a-naphthalene acetic acid (NAA; 3 microM) and benzyl adenine (3 microM) in combination. The nodal segments were primed on 'Growtak Sieve' for 48 h on MS medium containing sucrose (2%), polyvinyl pyrollidone (200 mgL(-1)) as antioxidant. About 80% of primed nodal segments responded positively and formed approximately 12 adventitious shoot buds per explants from explants collected during October-November months of every year. The shoot buds converted into plantlets on MS medium containing sucrose (3%) and kinetin (3 microM) where approximately 7 micro shoots developed per subculture after 8 weeks of culture. The regenerated micro shoots induced average 14 roots/plant on medium containing NAA (3 microM). The regenerates were hardened for 6-7 weeks on medium with 1/2MS salt solution and sucrose (2%) under normal laboratory condition before transferring to potting mix. About 70% transplants survived after two months of transfer.

  20. Reproductive biology of Syzygiella rubricaulis (Nees) Steph. (Adelanthaceae, Marchantiophyta), a liverwort disjunctly distributed in high-altitude Neotropical mountains.

    PubMed

    Maciel-Silva, A S; Gaspar, E P; da Conceição, F P; Dias Dos Santos, N; Pinheiro da Costa, D

    2016-07-01

    Syzygiella rubricaulis is a dioecious leafy liverwort disjunctly distributed and restricted to high-altitude mountains in the Neotropics and the Azores. This study is part of a larger project examining the phylogeography of S. rubricaulis in the Neotropics, and our main goals were to understand its reproductive biology, where sex expression occurs, if vegetative propagules are frequently found, how the sexes are distributed in populations, how frequently sporophytes are formed and what environmental conditions influence sexual expression. S. rubricaulis patches are mostly female, but all patches also contain non sex-expressing shoots. Out of 42 patches examined, 29 (69%) were sex-expressing: 25 were unisexual (21 female and four male) and four of mixed sex (two male-biased and two unbiased). At shoot level, out of 4200 shoots 18% were female and 7% male; among sex-expressing shoots, 73% were female, representing a sex ratio of 0.8 (female-biased). We encountered a total of 33 sporophytes in six patches (in Brazil, Venezuela and Ecuador). Leaf regenerants were found in one patch in Mexico. Low rates of sporophytes were likely related to low frequencies of male shoots and large distances between the sexes. As 25% of S. rubricaulis shoots expressed sex (occasionally producing sporophytes), we suggest that short-distance (and rarely long-distance) spore dispersal events occur in mountainous areas on a short-term basis. On a long-term basis, however, these events likely contribute to dynamic exchanges among populations in the Neotropics.

  1. Na-22, Ne-E, extinct radioactive anomalies and unsupported Ar-40. [in cooling ejecta of explosive nucleosynthesis

    NASA Technical Reports Server (NTRS)

    Clayton, D. D.

    1975-01-01

    The possibility that the origin of extinct radioactivities depended on their living long enough for grains to form in the expanding nucleosynthetic envelope, rather than on their living long enough for meteorites to form, is examined. As an example, the interpretation of Na-22 as a detectable extinct radioactivity, with a half life of only 2.6 years, is explored and related to Ne-22 occurrence. Similar arguments involving He-4, Ar-40, K-40, K-41, and calcium, titanium, chromium, manganese, iron, nickel, and cobalt isotopes are briefly presented.

  2. An effective protein extraction method for two-dimensional electrophoresis in the anticancer herb Andrographis paniculata Nees.

    PubMed

    Talei, Daryush; Valdiani, Alireza; Puad, Mohd Abdullah

    2013-01-01

    Proteomic analysis of plants relies on high yields of pure protein. In plants, protein extraction and purification present a great challenge due to accumulation of a large amount of interfering substances, including polysaccharides, polyphenols, and secondary metabolites. Therefore, it is necessary to modify the extraction protocols. A study was conducted to compare four protein extraction and precipitation methods for proteomic analysis. The results showed significant differences in protein content among the four methods. The chloroform-trichloroacetic acid-acetone method using 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) buffer provided the best results in terms of protein content, pellets, spot resolution, and intensity of unique spots detected. An overall of 83 qualitative or quantitative significant differential spots were found among the four methods. Based on the 2-DE gel map, the method is expected to benefit the development of high-level proteomic and biochemical studies of Andrographis paniculata, which may also be applied to other recalcitrant medicinal plant tissues.

  3. Proteomic analysis of the salt-responsive leaf and root proteins in the anticancer plant Andrographis paniculata Nees.

    PubMed

    Talei, Daryush; Valdiani, Alireza; Rafii, Mohd Yusop; Maziah, Mahmood

    2014-01-01

    Separation of proteins based on the physicochemical properties with different molecular weight and isoelectric points would be more accurate. In the current research, the 45-day-old seedlings were treated with 0 (control) and 12 dS m(-1) of sodium chloride in the hydroponic system. After 15 days of salt exposure, the total protein of the fresh leaves and roots was extracted and analyzed using two-dimensional electrophoresis system (2-DE). The analysis led to the detection of 32 induced proteins (19 proteins in leaf and 13 proteins in the root) as well as 12 upregulated proteins (four proteins in leaf and eight proteins in the root) in the salt-treated plants. Of the 44 detected proteins, 12 were sequenced, and three of them matched with superoxide dismutase, ascorbate peroxidase and ribulose-1, 5-bisphosphate oxygenase whereas the rest remained unknown. The three known proteins associate with plants response to environmental stresses and could represent the general stress proteins in the present study too. In addition, the proteomic feedback of different accessions of A. paniculata to salt stress can potentially be used to breed salt-tolerant varieties of the herb.

  4. Salt stress-induced protein pattern associated with photosynthetic parameters and andrographolide content in Andrographis paniculata Nees.

    PubMed

    Talei, Daryush; Valdiani, Alireza; Maziah, Mahmood; Sagineedu, Sreenivasa Rao; Abiri, Rambod

    2015-01-01

    Andrographis paniculata is a multifunctional medicinal plant and a potent source of bioactive compounds. Impact of environmental stresses such as salinity on protein diversification, as well as the consequent changes in the photosynthetic parameters and andrographolide content (AG) of the herb, has not yet been thoroughly investigated. The present study showed that the salinity affects the protein pattern, and subsequently, it decreased the photosynthetic parameters, protein content, total dry weight, and total crude extract. Exceptionally, the AG content was increased (p ≤ 0.01). Moreover, it was noticed that the salinity at 12 dS m(-1) led to the maximum increase in AG content in all accessions. Interestingly, the leaf protein analysis revealed that the two polymorphic protein bands as low- and medium-sized of 17 and 45 kDa acted as the activator agents for the photosynthetic parameters and AG content. Protein sequencing and proteomic analysis can be conducted based on the present findings in the future.

  5. Efficacy of crude extracts of Andrographis paniculata nees. on Callosobruchus chinensis L. during post harvest storage of cowpea.

    PubMed

    Bright, A A; Babu, A; Ignacimuth, S; Dorn, S

    2001-07-01

    Bioefficacy of different solvent fractions of A. paniculata was tested against the cowpea weevil, C. chinensis in terms of its effect on adult mortality, total egg output and emergence of F1 adults. All the extracts were effective against the weevil, the efficacy was however more significant with respect to methanol and ethyl acetate extracts at the highest concentrations (1,000 ppm) which lead to 72.01 and 67.69% adult mortality respectively. The efficacy was dose dependent. Total egg and percent emergence of Fl adults were lowest for methanol followed by ethyl acetate fractions. Possible role of the principal chemical constituents of this plant in bringing about mortality of the pest, reduction in egg laying and adult emergence are discussed.

  6. Involvement of monoaminergic system in the antidepressant-like effect of riparin I from Aniba riparia (Nees) Mez (Lauraceae) in mice.

    PubMed

    de Sousa, Francisca Cléa Florenço; Oliveira, Iris Cristina Maia; Silva, Maria Izabel Gomes; de Melo, Carla Thiciane Vasconcelos; Santiago, Vívian Romero; de Castro Chaves, Raquell; Fernandes, Mariana Lima; Gutierrez, Stanley Juan Chaves; Vasconcelos, Silvânia Maria Mendes; Macêdo, Danielle Silveira; Barbosa Filho, José Maria

    2014-02-01

    In past studies conducted by our group, riparin I (rip I) isolated from the green fruit of Aniba riparia presented antianxiety effects in mice, while its analogs rip II and III showed anxiolytic and antidepressant-like actions. This time around, we investigated a possible antidepressant activity of rip I using the forced swimming test (FST) and tail suspension test (TST) as predictive tests for antidepressant activity in rodents. In addition, the involvement of the monoaminergic system in this effect was also assessed. rip I was acutely administered by intraperitoneal (i.p.) and oral (p.o) routes to male mice at doses of 25 and 50 mg/kg. Results showed that rip I at both tested doses and administration routes produced a significant decrease in immobility time in FST and TST. The pretreatment of mice with prazosin (1 mg/kg, i.p., an α₁ -adrenoceptor antagonist), yohimbine (1 mg/kg, i.p., an α₂ -adrenoceptor antagonist), SCH23390 (15 μg/kg, i.p., a dopamine D1 receptor antagonist), sulpiride (50 mg/kg, i.p., a dopamine D2 receptor antagonist), p-chlorophenylalanine (100 mg/kg, an inhibitor of serotonin synthesis) or ritanserin (4 mg/kg, a serotonin 5-HT2(A)/2(C) receptor antagonist) blocked the anti-immobility effects elicited by rip I (50 mg/kg, p.o.) in the FST. Taken together, results indicate that rip I produces significant antidepressant-like activity in the FST and TST, and this effect seems to be dependent on its interaction with noradrenergic, dopaminergic and serotonergic systems.

  7. Evaluation of anti-bacterial and anti-oxidant potential of andrographolide and echiodinin isolated from callus culture of Andrographis paniculata Nees

    PubMed Central

    Arifullah, Mohmmed; Namsa, Nima Dandu; Mandal, Manabendra; Chiruvella, Kishore Kumar; Vikrama, Paritala; Gopal, Ghanta Rama

    2013-01-01

    Objective To evaluate the anti-bacterial and anti-oxidant activity of andrographolide (AND) and echiodinin (ECH) of Andrographis paniculata. Methods In this study, an attempt has been made to demonstrate the anti-microbial and anti-oxidant activity of isolated AND and ECH by broth micro-dilution method and 2,2-diphenyl-2-picryl-hydrazyl (DPPH) assay, respectively. Structure elucidation was determined by electro-spray ionization-MSD, NMR (1H and 13C) and IR spectra. Results AND was effective against most of the strains tested including Mycobacterium smegmatis, showing broad spectrum of growth inhibition activity with Minimum inhibitory concentration values against Staphylococcus aureus (100 µg/mL), Streptococcus thermophilus (350 µg/mL) Bacillus subtilis (100 µg/mL), Escherichia coli (50 µg/mL), Mycobacterium smegmatis (200 µg/mL), Klebsiella pneumonia (100 µg/mL), and Pseudomonas aeruginosa (200 µg/mL). ECH showed specific anti-bacterial activity against Staphylococcus aureus, Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa at a concentration higher than 225 µg/mL. Both AND and ECH were not effective against the two yeast strains, Candida albicans and Saccharomyces cerevisiae tested in this study. Conclusion This preliminary study showed promising anti-bacterial activity and moderate free radical scavenging activity of AND and ECH, and it may provide the scientific rationale for its popular folklore medicines. PMID:23905016

  8. Recovery of lignin peroxidase from submerged liquid fermentation of Amauroderma rugosum (Blume & T. Nees) Torrend using polyethylene glycol/salt aqueous two-phase system.

    PubMed

    Jong, Wan Yng Linda; Show, Pau Loke; Ling, Tau Chuan; Tan, Yee Shin

    2017-07-01

    Amauroderma rugosum is a wild mushroom species widely distributed in tropics and is classified under the class of Basidiomycetes. Basidiomycetes are well-known for their abilities of producing lignocellulolytic enzymes such as lignin peroxidase (LiP), laccase (Lac) and manganese peroxidase (MnP). Different factors such as nutrient sources, incubation period and agitation affect the production of lignocellulolytic enzymes. The A. rugosum produced LiP in the medium supplemented with potato dextrose broth (PDB), 0.5% yeast and 1.0% saw dust at 26.70±3.31 U/mL. However, the LiP activity was increased to 106.32±5.32 U/mL when supplemented with 150 μm of copper (CuSO4). The aqueous two-phase system (ATPS) is a simple, rapid and low cost method for primary extraction and recovery of LiP. A total of 25 systems made from five different molecular weights of polyethylene glycol (PEG)/dipotassium hydrogen phosphate (K2HPO4) were tested. PEG 600 produced the highest top phase purification factor (PFT) of 1.33±0.62 with yield of 72.18±8.50%. The optimization of the ATPS parameters, such as volume ratio VR, pH and crude enzyme loading are the factors controlling the phase partition. Our results showed that significant improvement (PFT of 6.26±2.87 with yield of 87.31±3.14%) of LiP recovery can be achieved by optimized the parameters. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  9. Evaluation of in vitro antioxidant activity of Indian bay leaf, Cinnamomum tamala (Buch. -Ham.) T. Nees & Eberm using rat brain synaptosomes as model system.

    PubMed

    Devi, S Lakshmi; Kannappan, S; Anuradha, C V

    2007-09-01

    The study investigated the perturbation of oxidant-antioxidant balance in brain synaptosomes of diabetic rats and determined the antioxidant and free radical-scavenging property of the Indian bay leaf. Brain synaptosomes were isolated from control and streptozotocin-induced diabetic animals and oxidative stress parameters were assayed. A methanolic extract of bay leaf (BLE) was tested for the polyphenolic content and antioxidant activity by in vitro assays. A significant increase in the levels of lipids and lipid peroxidation products and a decline in antioxidant potential were observed in diabetic rat brain synaptosomes. The total polyphenolic content of BLE was found to be 6.7 mg gallic acid equivalents (GAE)/100g. BLE displayed scavenging activity against superoxide and hydroxyl radicals in a concentration-dependent manner. Further, BLE showed inhibition of Fe(2+)-ascorbate induced lipid peroxidation in both control and diabetic rat brain synaptosomes. Maximum inhibition of lipid peroxidation, radical scavenging action and reducing power of BLE were observed at a concentration of 220 microg GAE. These effects of BLE in vitro were comparable with that of butylated hydroxyl toluene (BHT), a synthetic antioxidant. It can be concluded that synaptosomes from diabetic rats are susceptible to oxidative damage and the positive effects of bay leaf in vitro, could be attributed to the presence of antioxidant phytochemicals.

  10. Novel inhibitory activity of the Staphylococcus aureus NorA efflux pump by a kaempferol rhamnoside isolated from Persea lingue Nees.

    PubMed

    Holler, Jes Gitz; Christensen, S Brøgger; Slotved, Hans-Christian; Rasmussen, Hasse B; Gúzman, Alfonso; Olsen, Carl-Erik; Petersen, Bent; Mølgaard, Per

    2012-05-01

    To isolate a plant-derived compound with efflux inhibitory activity towards the NorA transporter of Staphylococcus aureus. Bioassay-guided isolation was used, with inhibition of ethidium bromide efflux via NorA as a guide. Characterization of activity was carried out using MIC determination and potentiation studies of a fluoroquinolone antibiotic in combination with the isolated compound. Everted membrane vesicles of Escherichia coli cells enriched with NorA were prepared to study efflux inhibitory activity in an isolated manner. The ethanolic extract of Persea lingue was subjected to bioassay-guided fractionation and led to the isolation of the known compound kaempferol-3-O-α-L-(2,4-bis-E-p-coumaroyl)rhamnoside (compound 1). Evaluation of the dose-response relationship of compound 1 showed that ethidium bromide efflux was inhibited, with an IC(50) value of 2 μM. The positive control, reserpine, was found to have an IC(50) value of 9 μM. Compound 1 also inhibited NorA in enriched everted membrane vesicles of E. coli. Potentiation studies revealed that compound 1 at 1.56 mg/L synergistically increased the antimicrobial activity of ciprofloxacin 8-fold against a NorA overexpresser, and the synergistic activity was exerted at a fourth of the concentration necessary for reserpine. Compound 1 was not found to exert a synergistic effect on ciprofloxacin against a norA deletion mutant. The 2,3-coumaroyl isomer of compound 1 has been shown previously not to cause acute toxicity in mice at 20 mg/kg/day. Our results show that compound 1 acts through inhibition of the NorA efflux pump. Combination of compound 1 with subinhibitory concentrations of ciprofloxacin renders a wild-type more susceptible and a NorA overexpresser S. aureus susceptible.

  11. Improving Hatchery Effectiveness as Related to Smoltification: Proceedings of a Workshop held at Kah-Nee-Tah Lodge, Warm Springs, Oregon, May 20-23, 1985.

    SciTech Connect

    Bouck, Gerald R.

    1987-05-01

    The Bonneville Power Administration (BPA) intends to develop a smoltification research effort that would have broad support among the interested parties. BPA sponsored this workshop on smoltification and related research to gather leading technical experts in the field in smoltification, permit them to exchange information about the state of the art of smoltification research, and allow them to identify and rank high-priority projects. This document includes keynote speeches, technical papers, and other sessions that summarize both what is known and what information is needed.

  12. Larvicidal efficacy of Adhatoda vasica (L.) Nees against the bancroftian filariasis vector Culex quinquefasciatus Say and dengue vector Aedes aegypti L. in in vitro condition.

    PubMed

    Thanigaivel, Annamalai; Chandrasekaran, Rajamanickam; Revathi, Kannan; Nisha, Selvamathiazhagan; Sathish-Narayanan, Subbiah; Kirubakaran, Suyambulingam Arunachalam; Senthil-Nathan, Sengottayan

    2012-05-01

    The larvicidal activities of methanolic fractions from Adhatoda vasica leaf extracts were investigated against the bancroftian filariasis vector Culex quinquefasciatus and dengue vector Aedes aegypti. The results indicated that the mortality rates was high at 100, 150, 200 and 250 ppm of methanol extract of fractions III with R (f) value 0.67 and methanol extract of fraction V with R (f) value 0.64 of A. vasica against all the larval instars of C. quinquefasciatus and A. aegypti. The result of log probit analysis (at 95% confidence level) revealed that lethal concentration, LC(50) and LC(90) values were 106.13 and 180.6 ppm for fraction III, 110.6 and 170 ppm for fraction V of C. quinquefasciatus. And, the LC(50) and LC(90) values were 157.5 and 215.5 ppm for fraction III of A. aegypti and 120 and 243.5 ppm for the fraction V of A. aegypti, respectively. All the tested fractions proved to have strong larvicidal activity (doses from 100 to 250 ppm) against C. quinquefasciatus and A. aegypti. In general, second instar was more susceptible than the later instar. The results achieved suggest that, in addition to their ethnopharmacology value, A. vasica may also serve as a natural larvicidal agent.

  13. Validation of a method for the determination of sterols and triterpenes in the aerial part of Justicia anselliana (Nees) T. Anders by capillary gas chromatography.

    PubMed

    Kpoviéssi, Dossou Sika Salomé; Gbaguidi, Fernand; Gbénou, Joachim; Accrombessi, Georges; Moudachirou, Mansourou; Rozet, Eric; Hubert, Philippe; Quetin-Leclercq, Joëlle

    2008-12-01

    An accurate and sensitive method, combining soxhlet extraction, solid phase-extraction and capillary gas chromatography is described for the quantitative determination of one triterpene (lupeol) and three sterols (stigmasterol, campesterol and beta-sitosterol) and the detection of another triterpene (alpha-amyrin) from the aerial part of Justicia anselliana. This is the first method allowing the quantification of sterols and triterpenes in this plant. It has been fully validated in order to be able to compare the sterol and triterpene composition of different samples of J. anselliana and therefore help to explain the allelopathic activity due to these compounds. This method showed that the aerial part of J. anselliana contained (292+/-2)mg/kg of lupeol, (206+/-1)mg/kg of stigmasterol, (266+/-2)mg/kg of campesterol and (184+/-9)mg/kg of beta-sitosterol.

  14. Geranyl acetate esterase controls and regulates the level of geraniol in lemongrass (Cymbopogon flexuosus Nees ex Steud.) mutant cv. GRL-1 leaves.

    PubMed

    Ganjewala, Deepak; Luthra, Rajesh

    2009-01-01

    Essential oil isolated from lemongrass (Cymbopogon flexuosus) mutant cv. GRL-1 leaves is mainly composed of geraniol (G) and geranyl acetate (GA). The proportion of G and GA markedly fluctuates during leaf development. The proportions of GA and G in the essential oil recorded at day 10 after leaf emergence were approximately 59% and approximately 33% respectively. However, the level of GA went down from approximately 59 to approximately 3% whereas the level of G rose from approximately 33 to approximately 91% during the leaf growth period from day 10 to day 50. However, the decline in the level of GA was most pronounced in the early (day 10 to day 30) stage of leaf growth. The trend of changes in the proportion of GA and G has clearly indicated the role of an esterase that must be involved in the conversion of GA to G during leaf development. We isolated an esterase from leaves of different ages that converts GA into G and has been given the name geranyl acetate esterase (GAE). The GAE activity markedly varied during the leaf development cycle; it was closely correlated with the monoterpene (GA and G) composition throughout leaf development. GAE appeared as several isoenzymes but only three (GAE-I, GAE-II, and GAE-III) of them had significant GA cleaving activity. The GAE isoenzymes pattern was greatly influenced by the leaf developmental stages and so their GA cleaving activities. Like the GAE activity, GAE isoenzyme patterns were also found to be consistent with the monoterpene (GA and G) composition. GAE had an optimum pH at 8.5 and temperature at 30 degrees C. Besides GAE, a compound with phosphatase activity capable of hydrolyzing geranyl diphosphate (GPP) to produce geraniol has also been isolated.

  15. Seismic Risk Reduction for Soft-Story Wood-Frame Buildings: Test Results and Retrofit Recommendations from the Nees-Soft Project

    Treesearch

    John W. van de Lindt; Pouria Bahmani; Mikhail Gershfeld; Gary Mochizuki; Xiaoyun Shao; Steven E. Pryor; Weichiang Pang; Michael D. Symans; Jingjing Tian; Ershad Ziaei; Elaina N. Jennings; Douglas Rammer

    2014-01-01

    There are thousands of soft-story wood-frame buildings in California which have been recognized as a disaster preparedness problem with concerted mitigation efforts underway in many cities throughout the state. The vast majority of those efforts are based on numerical modelling, often with half-century old data in which assumptions have to be made based on engineering...

  16. Status of Sassafras albidum (Nutt.) Nees in the presence of laurel wilt disease and throughout the eastern United States

    Treesearch

    KaDonna C. Randolph

    2017-01-01

    Sassafras albidum (Sassafras) is an ecologically important tree species that is widely distributed throughout the eastern United States. Sassafras is presently threatened by Raffaelea lauricola, a fungus vectored by Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae; Redbay Ambrosia Beetle), which...

  17. Evaluation of anti-bacterial and anti-oxidant potential of andrographolide and echiodinin isolated from callus culture of Andrographis paniculata Nees.

    PubMed

    Arifullah, Mohmmed; Namsa, Nima Dandu; Mandal, Manabendra; Chiruvella, Kishore Kumar; Vikrama, Paritala; Gopal, Ghanta Rama

    2013-08-01

    To evaluate the anti-bacterial and anti-oxidant activity of andrographolide (AND) and echiodinin (ECH) of Andrographis paniculata. In this study, an attempt has been made to demonstrate the anti-microbial and anti-oxidant activity of isolated AND and ECH by broth micro-dilution method and 2,2-diphenyl-2-picryl-hydrazyl (DPPH) assay, respectively. Structure elucidation was determined by electro-spray ionization-MSD, NMR ((1)H and (13)C) and IR spectra. AND was effective against most of the strains tested including Mycobacterium smegmatis, showing broad spectrum of growth inhibition activity with Minimum inhibitory concentration values against Staphylococcus aureus (100 µg/mL), Streptococcus thermophilus (350 µg/mL) Bacillus subtilis (100 µg/mL), Escherichia coli (50 µg/mL), Mycobacterium smegmatis (200 µg/mL), Klebsiella pneumonia (100 µg/mL), and Pseudomonas aeruginosa (200 µg/mL). ECH showed specific anti-bacterial activity against Staphylococcus aureus, Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa at a concentration higher than 225 µg/mL. Both AND and ECH were not effective against the two yeast strains, Candida albicans and Saccharomyces cerevisiae tested in this study. This preliminary study showed promising anti-bacterial activity and moderate free radical scavenging activity of AND and ECH, and it may provide the scientific rationale for its popular folklore medicines.

  18. A method to estimate the additional uncertainty in gap-filled NEE resulting from long gaps in the CO2 flux record

    Treesearch

    Andrew D. Richardson; David Y. Hollinger

    2007-01-01

    Missing values in any data set create problems for researchers. The process by which missing values are replaced, and the data set is made complete, is generally referred to as imputation. Within the eddy flux community, the term "gap filling" is more commonly applied. A major challenge is that random errors in measured data result in uncertainty in the gap-...

  19. A Phenylurea Cytokinin, CPPU, Elevated Reducing Sugar and Correlated to Andrographolide Contents in Leaves of Andrographis paniculata (Burm. F.) Wall. Ex Nees.

    PubMed

    Worakan, Phapawee; Karaket, Netiya; Maneejantra, Nuchada; Supaibulwatana, Kanyaratt

    2017-02-01

    Cytokinins are phytohormones that play multiple roles to control plant growth and development. In this study, leaf biomass and the production of andrographolide compounds in a medicinal plant Andrographis paniculata were significantly increased after exogenously treating with the synthetic cytokinin cytokinin-1-(2-chloro-4-pyridyl)-3-phenylurea (CPPU) at 0 (water), 5, or 10 mg L(-1) and observed the results for 24 h, 48 h, and 7 days of treatment. It was found that CPPU could significantly enhance new axillary bud formation and further promote branching 4.6-5.6-fold higher, resulting in higher fresh weight (FW) and dry weight (DW) than the control. Application of CPPU at 5 mg L(-1) significantly promoted the highest contents of total reducing sugar at 2.5-fold in leaves and at 1.5-fold in roots. Although treatments of CPPU significantly affected the increasing contents of chlorophyll and carotenoid (1.2-1.6-fold), CPPU at 10 mg L(-1) slightly caused leaf stress and chlorophyll reduction. Interestingly, 5 mg L(-1) CPPU could enhance andrographolide content, an active anti-infectious compound in Andrographis paniculata (2.2-fold higher than the control) that reached the highest content at 24 h after treatment. This study suggested that CPPU should be suitable for field application to promote leaf yields and induce the production of useful pharmaceutical compounds in Andrographis paniculata.

  20. Attenuation of Inflammatory Mediators (TNF-α and Nitric Oxide) and Up-Regulation of IL-10 by Wild and Domesticated Basidiocarps of Amauroderma rugosum (Blume & T. Nees) Torrend in LPS-Stimulated RAW264.7 Cells

    PubMed Central

    2015-01-01

    Amauroderma rugosum, commonly known as “Jiǎzī” in China, is a wild mushroom traditionally used by the Chinese to reduce inflammation, to treat diuretic and upset stomach, and to prevent cancer. It is also used by the indigenous communities in Malaysia to prevent epileptic episodes and incessant crying by babies. The aim of this study was to compare the wild and domesticated basidiocarps of A. rugosum for antioxidant and in vitro anti-inflammatory effects in LPS-stimulated RAW264.7 cells. The wild basidiocarps of A. rugosum were collected from the Belum Forest, Perak, Malaysia and the domesticated basidiocarps of A. rugosum were cultivated in the mushroom house located in the University of Malaya, Kuala Lumpur, Malaysia. Both the wild and domesticated basidiocarps were subjected to ethanolic extraction and the extracts were tested for antioxidant and anti-inflammatory activities. In this study, the crude ethanolic extract of wild (WB) and domesticated (DB) basidiocarps of A. rugosum had comparable total phenolic content and DPPH scavenging activity. However, WB (EC50 = 222.90 μg/mL) displayed a better ABTS cation radical scavenging activity than DB (EC50 = 469.60 μg/mL). Both WB and DB were able to scavenge nitric oxide (NO) radical and suppress the NO production in LPS-stimulated RAW264.7 cells and this effect was mediated through the down-regulation of inducible nitric oxide synthase (iNOS) gene. In addition, both WB and DB caused down-regulation of the inflammatory gene TNF-α and the up-regulation of the anti-inflammatory gene IL-10. There was no inhibitory effect of WB and DB on nuclear translocation of NF-κB p65. In conclusion, the wild and domesticated basidiocarps of A. rugosum possessed antioxidant and in vitro anti-inflammatory properties. WB and DB inhibited downstream inflammatory mediators (TNF-α and NO) and induced anti-inflammatory cytokine IL-10 production. No inhibitory effects shown on upstream nuclear translocation of NF-κB p65. WB and DB exhibited antioxidant activity and attenuation of proinflammatory mediators and therefore, A. rugosum may serve as a potential therapeutic agent in the management of inflammation. PMID:26427053

  1. Evidence for the involvement of the serotonergic, noradrenergic, and dopaminergic systems in the antidepressant-like action of riparin III obtained from Aniba riparia (Nees) Mez (Lauraceae) in mice.

    PubMed

    Melo, Carla Thiciane Vasconcelos; de Carvalho, Alyne Mara Rodrigues; Moura, Brinell Arcanjo; Teixeira, Caroline Porto Leite; Vasconcelos, Leonardo Freire; Feitosa, Mariana Lima; de Oliveira, Gersilene Valente; Barbosa-Filho, José Maria; Chavez Gutierrez, Stanley Juan; de França Fonteles, Marta Maria; Vasconcelos, Silvânia Maria Mendes; de Sousa, Francisca Cléa Florenço

    2013-02-01

    Previous work has shown that intraperitoneal administration of riparin III (ripIII) reduces immobility time in the forced swimming test (FST), which suggests potential antidepressant activity. As the mechanism of action is not completely understood, this study is aimed at investigating the antidepressant-like action of ripIII. Following intraperitoneal administration of ripIII at doses of 25 and 50 mg/kg, there were decreases in the immobility time in the FST and tail suspension test without accompanying changes in ambulation (data not shown). The pretreatment of mice with sulpiride (50 mg/kg, i.p.), prazosin (1 mg/kg, i.p.), yohimbine (1 mg/kg, i.p.), and p-chlorophenylalanine (PCPA, 100 mg/kg, i.p. for, four consecutive days) significantly prevented the anti-immobility effect of ripIII in the FST. On the other hand, the anti-immobility effect of ripIII (50 mg/kg, v.o.) was not altered by pretreatment of mice with SCH23390 (15 μg/kg, i.p.) Furthermore, ripIII potentiated the sleeping latency and sleeping time of the pentobarbital-induced sleeping time test and also potentiated apomorphine (16 mg/kg, i.p.)-induced hypothermia in mice. In conclusion, the present study provides evidence that the antidepressant-like effect of ripIII is dependent on its interaction with the serotonergic, noradrenergic (α₁- and α₂- receptors), and dopaminergic (dopamine D₂ receptors) systems. © 2011 The Authors Fundamental and Clinical Pharmacology © 2011 Société Française de Pharmacologie et de Thérapeutique.

  2. FINAL REPORT: EDDY-COVARIANCE FLUX TOWER AND TRACER TECHNOLOGY SUPPORT FOR THE UNIVERSITY OF GEORGIA PROPOSAL: FROM TOWER TO PIXEL: INTEGRATION OF PATCH-SIZE NEE USING EXPERIMENTAL MODELING FOOTPRINT ANALYSIS.

    SciTech Connect

    LEWIN,K.F.; NAGY, J.; WATSON, T.B.

    2007-09-01

    Brookhaven National Laboratory has been funded since October of 2000 to provide assistance to the University of Georgia in conducting footprint analyses of individual towers based on meteorology and trace gas measurements. Brookhaven researchers conducted air flow measurements using perfluorocarbon tracers and meteorological instrumentation for three experimental campaigns at an AmeriFlux research site maintained by Dr. Monique Leclerc near Gainesville, FL. In addition, BNL provided assistance with remote data collection and distribution from remote field sites operated by Dr. John Hom of the US Forest Service in the Pine Barrens of New Jersey and at FACE research sites in North Carolina and Wisconsin.

  3. Recommended Species for Vegetative Stabilization of Training Lands in Arid and Semi-Arid Environments

    DTIC Science & Technology

    1985-09-01

    semibacata Awnless bush sunflower Helianthus sp. Bahia grass Paspalum notatum Barley Hordeum vulgare Basin wildrye Elymus cinereus Bearded wheatgrass...Boer lovegrass Eragrostis curvuLa *Brittlebush Encelia farinosa *Brome grasses Bromus spp. Buckwheat s Eriogonum spp. Buffalograss Buchloe dactyloides...mexicana *Millets Panicum spp. Mountain brome Bromus montanum Mountain mahogany Gercocarpus montanus *Mountain penstenion Penstemon montanus *Muhly grasses

  4. Plastic traits of an exotic grass contribute to its abundance but are not always favourable.

    PubMed

    Firn, Jennifer; Prober, Suzanne M; Buckley, Yvonne M

    2012-01-01

    In herbaceous ecosystems worldwide, biodiversity has been negatively impacted by changed grazing regimes and nutrient enrichment. Altered disturbance regimes are thought to favour invasive species that have a high phenotypic plasticity, although most studies measure plasticity under controlled conditions in the greenhouse and then assume plasticity is an advantage in the field. Here, we compare trait plasticity between three co-occurring, C(4) perennial grass species, an invader Eragrostis curvula, and natives Eragrostis sororia and Aristida personata to grazing and fertilizer in a three-year field trial. We measured abundances and several leaf traits known to correlate with strategies used by plants to fix carbon and acquire resources, i.e. specific leaf area (SLA), leaf dry matter content (LDMC), leaf nutrient concentrations (N, C:N, P), assimilation rates (Amax) and photosynthetic nitrogen use efficiency (PNUE). In the control treatment (grazed only), trait values for SLA, leaf C:N ratios, Amax and PNUE differed significantly between the three grass species. When trait values were compared across treatments, E. curvula showed higher trait plasticity than the native grasses, and this correlated with an increase in abundance across all but the grazed/fertilized treatment. The native grasses showed little trait plasticity in response to the treatments. Aristida personata decreased significantly in the treatments where E. curvula increased, and E. sororia abundance increased possibly due to increased rainfall and not in response to treatments or invader abundance. Overall, we found that plasticity did not favour an increase in abundance of E. curvula under the grazed/fertilized treatment likely because leaf nutrient contents increased and subsequently its' palatability to consumers. E. curvula also displayed a higher resource use efficiency than the native grasses. These findings suggest resource conditions and disturbance regimes can be manipulated to disadvantage

  5. Plastic Traits of an Exotic Grass Contribute to Its Abundance but Are Not Always Favourable

    PubMed Central

    Firn, Jennifer; Prober, Suzanne M.; Buckley, Yvonne M.

    2012-01-01

    In herbaceous ecosystems worldwide, biodiversity has been negatively impacted by changed grazing regimes and nutrient enrichment. Altered disturbance regimes are thought to favour invasive species that have a high phenotypic plasticity, although most studies measure plasticity under controlled conditions in the greenhouse and then assume plasticity is an advantage in the field. Here, we compare trait plasticity between three co-occurring, C4 perennial grass species, an invader Eragrostis curvula, and natives Eragrostis sororia and Aristida personata to grazing and fertilizer in a three-year field trial. We measured abundances and several leaf traits known to correlate with strategies used by plants to fix carbon and acquire resources, i.e. specific leaf area (SLA), leaf dry matter content (LDMC), leaf nutrient concentrations (N, C∶N, P), assimilation rates (Amax) and photosynthetic nitrogen use efficiency (PNUE). In the control treatment (grazed only), trait values for SLA, leaf C∶N ratios, Amax and PNUE differed significantly between the three grass species. When trait values were compared across treatments, E. curvula showed higher trait plasticity than the native grasses, and this correlated with an increase in abundance across all but the grazed/fertilized treatment. The native grasses showed little trait plasticity in response to the treatments. Aristida personata decreased significantly in the treatments where E. curvula increased, and E. sororia abundance increased possibly due to increased rainfall and not in response to treatments or invader abundance. Overall, we found that plasticity did not favour an increase in abundance of E. curvula under the grazed/fertilized treatment likely because leaf nutrient contents increased and subsequently its' palatability to consumers. E. curvula also displayed a higher resource use efficiency than the native grasses. These findings suggest resource conditions and disturbance regimes can be manipulated to

  6. Notes on Citrullius spp. and Acanthosicyos naudinianus

    USDA-ARS?s Scientific Manuscript database

    Scanning electron and light microscopy were utilized to examine pollen of the currently recognized species (and forms) within the genus Citrullus (Cucurbitaceae). Materials examined included: C. lanatus (Thunb.) Matsum. & Nakai including the citron (C. amarus Schrad.) and egusi (C. lanatus subsp. mu...

  7. Notes on Citrullus spp. And Acanthosicyos naudinianus-pollen morphology and interspecific hybridization

    USDA-ARS?s Scientific Manuscript database

    Scanning electron and light microscopy were utilized to examine pollen of the currently recognized species (and forms) within the genus Citrullus (Cucurbitaceae). Materials examined included: C. lanatus (Thunb.) Matsum. & Nakai including the citron (C. amarus Schrad.) and egusi (C. mucosospermus (Fu...

  8. Genetic relationships in the desert watermelon citrullus colocynthis as viewed with high-frequency, oligonucleotide–targeting active gene (HFO–TAG) markers

    USDA-ARS?s Scientific Manuscript database

    U.S. Plant Introductions (PIs) of Citrullus colocynthis (L.) Schrad. are a viable source for enhancing disease and pest resistance in watermelon cultivars. However, there is information about their genetic diversity and relationships to watermelon cultivars. Genetic diversity and relationships were ...

  9. Genetic diversity in the desert watermelon Citrullus colocynthis and its relationship with Citrullus species as determined by high-frequency oligonucleotides-targeting active gene markers

    USDA-ARS?s Scientific Manuscript database

    Citrullus colocynthis (L.) Schrad. is a viable source of genes for enhancing disease and pest resistance in the cultivated watermelon. However, there is little information in the literature about genetic diversity within C. colocynthis (CC) or the relationship of specific genotypes of CC to C. lanat...

  10. Utilizing genetic diversity in the desert watermelon citrullus colocynthis for enhancing watermelon cultivars for resistance to biotic and abiotic stress

    USDA-ARS?s Scientific Manuscript database

    Wide genetic diversity exists among the desert watermelon Citrullus colocynthis (L.) Schrad. (CC) accessions collected in the deserts of northern Africa, the Middle East, and Asia. Because of their resistance to biotic and abiotic stresses, there can be a viable source of genes used for enhancing wa...

  11. Observations on anatomical aspects of the fruit, leaf and stem tissues of four Citrullus spp.

    USDA-ARS?s Scientific Manuscript database

    Morphological characteristics of the fruit, stem and leaf tissues of four species of Citrullus (L.) Schrad. were examined using standard histological methods. Plant materials included the cultivated watermelon (C. lanatus (Thunb.) Matsum. & Nakai) and three of its related species; C. colocynthis (...

  12. 'Snowstorm' a new forage kochia cultivar with improved stature, productivity, and nutritional content for enhanced fall and winter grazing

    USDA-ARS?s Scientific Manuscript database

    'Snowstorm' forage kochia (Bassia prostrata [L.] A.J. Scott) (synonym=Kochia prostrata [L.] Schrad.) (Reg. No. CV-_____, PI _____) was released on March 22, 2012, by the USDA-ARS and the Utah Agricultural Experiment Station. Snowstorm was evaluated as OTVSEL and Otavny-select, and was developed as ...

  13. Drought Tolerance of Selected Eragrostis Species Correlates with Leaf Tensile Properties

    PubMed Central

    BALSAMO, R. A.; WILLIGEN, C. VANDER; BAUER, A. M.; FARRANT, J.

    2006-01-01

    • Background and Aims Previous studies on grass leaf tensile properties (behaviour during mechanical stress) have focused on agricultural applications such as resistance to trampling and palatability; no investigations have directly addressed mechanical properties during water stress, and hence these are the subject of this study. • Methods Critical (lethal) relative water contents were determined for three species of grass in the genus Eragrostis varying in their tolerance to drought. Measurements were taken for leaf tensile strength, elastic modulus, toughness and failure load under different conditions of hydration, and light microscopy and histochemical analyses were undertaken. • Key Results Leaf tensile strength of fully hydrated leaves for the drought-intolerant E. capensis, the moderately drought-tolerant E. tef and the drought-tolerant E. curvula correlated well with drought tolerance (critical relative water content). Eragrostis curvula had higher tensile strength values than E. tef, which in turn had higher values than E. capensis. Measurements on the drought-tolerant grass E. curvula when fully hydrated and when dried to below its turgor loss point showed that tensile strength, toughness and the elastic modulus all increased under conditions of turgor loss, while the failure load remained unchanged. Additional tests of 100 mm segments along the lamina of E. curvula showed that tensile strength, toughness and the elastic modulus all decreased with distance from the base of the lamina, while again the failure load was unaffected. This decrease in mechanical parameters correlated with a reduction in the size of the vascular bundles and the amount of lignification, as viewed in lamina cross-sections. • Conclusions The results confirm that leaf mechanical properties are affected by both water status and position along the lamina, and suggest a positive correlation between leaf internal architecture, tensile strength, cell wall chemistry and

  14. Drought tolerance of selected Eragrostis species correlates with leaf tensile properties.

    PubMed

    Balsamo, R A; Willigen, C Vander; Bauer, A M; Farrant, J

    2006-06-01

    Previous studies on grass leaf tensile properties (behaviour during mechanical stress) have focused on agricultural applications such as resistance to trampling and palatability; no investigations have directly addressed mechanical properties during water stress, and hence these are the subject of this study. Critical (lethal) relative water contents were determined for three species of grass in the genus Eragrostis varying in their tolerance to drought. Measurements were taken for leaf tensile strength, elastic modulus, toughness and failure load under different conditions of hydration, and light microscopy and histochemical analyses were undertaken. Leaf tensile strength of fully hydrated leaves for the drought-intolerant E. capensis, the moderately drought-tolerant E. tef and the drought-tolerant E. curvula correlated well with drought tolerance (critical relative water content). Eragrostis curvula had higher tensile strength values than E. tef, which in turn had higher values than E. capensis. Measurements on the drought-tolerant grass E. curvula when fully hydrated and when dried to below its turgor loss point showed that tensile strength, toughness and the elastic modulus all increased under conditions of turgor loss, while the failure load remained unchanged. Additional tests of 100 mm segments along the lamina of E. curvula showed that tensile strength, toughness and the elastic modulus all decreased with distance from the base of the lamina, while again the failure load was unaffected. This decrease in mechanical parameters correlated with a reduction in the size of the vascular bundles and the amount of lignification, as viewed in lamina cross-sections. The results confirm that leaf mechanical properties are affected by both water status and position along the lamina, and suggest a positive correlation between leaf internal architecture, tensile strength, cell wall chemistry and tolerance to dehydration for grasses.

  15. Contrasting microbial biogeographical patterns between anthropogenic subalpine grasslands and natural alpine grasslands.

    PubMed

    Geremia, Roberto A; Pușcaș, Mihai; Zinger, Lucie; Bonneville, Jean-Marc; Choler, Philippe

    2016-02-01

    The effect of plant species composition on soil microbial communities was studied at the multiregional level. We compared the soil microbial communities of alpine natural grasslands dominated by Carex curvula and anthropogenic subalpine pastures dominated by Nardus stricta. We conducted paired sampling across the Carpathians and the Alps and used Illumina sequencing to reveal the molecular diversity of soil microbes. We found that bacterial and fungal communities exhibited contrasting regional distributions and that the distribution in each grassland is well discriminated. Beta diversity of microbial communities was much higher in C. curvula grasslands due to a marked regional effect. The composition of grassland-type core microbiomes suggest that C. curvula, and N. stricta to a lesser extent, tend to select a cohort of microbes related to antibiosis/exclusion, pathogenesis and endophytism. We discuss these findings in light of the postglacial history of the studied grasslands, the habitat connectivity and the disturbance regimes. Human-induced disturbance in the subalpine belt of European mountains has led to homogeneous soil microbial communities at large biogeographical scales. Our results confirm the overarching role of the dominant grassland plant species in the distribution of microbial communities and highlight the relevance of biogeographical history. © 2015 European Union. New Phytologist © 2015 New Phytologist Trust.

  16. Preliminary Guide to the Onsite Identification and Delineation of the Wetlands of the North Atlantic United States.

    DTIC Science & Technology

    1982-05-01

    Leatherleaf) Chamaecyparis thyoides (Atlantic white cedar) Fraxinus pennsylvanica (Green ash) Larix laricina (Tamarack) Osmunda spp. (Cinnamon fern...spp. Laurel Kochia scoparia (L.) Schrad. Summer cypress Kosteletzkya virginica (L.) Presl ex Gray Marsh mallow Larix laricina (Du Roi) K. Koch Larch...f Cyperus spp. (Sedges) b PAcea mariana (Black Spru~.e) g Nymphaea odorata (Waterlily) c Lanax laricina (Tamarack) h Myrica gale (Sweet Gale) d

  17. Screening of analgesic and anti-inflammatory activities of Citrullus colocynthis from southern Tunisia.

    PubMed

    Marzouk, Belsem; Marzouk, Zohra; Haloui, Ehsen; Fenina, Nadia; Bouraoui, Abderrahman; Aouni, Mahjoub

    2010-03-02

    Inflammations and immune-related diseases such as rheumatoid arthritis are growing global concerns. Most of the drugs from plants which have become important in modern medicine had a folklore origin and are traditional in systems of medicine. Citrullus colocynthis Schrad. (cucurbitaceae), endemic in Southern Tunisia, is used in folk medicine to treat many inflammation diseases. To evaluate the acute toxicity of different parts of Citrullus colocynthis and then to screen the analgesic and anti-inflammatory activities of aqueous extracts from roots and stems of the plant and from fruits and seeds at different maturation stages. After identification and acute toxicity assay Citrullus colocynthis Schrad. aqueous extracts were screened for analgesic and anti-inflammatory activities using, respectively, the acetic acid writhing test in mice and the carrageenan-induced paw edema assay in rats. All extracts displayed analgesic and anti-inflammatory activities at different doses without inducing acute toxicity. Topic results were obtained with immature fruits followed by seeds. The stem and root extracts were shown to possess the less significant inhibitory activity against analgesic and anti-inflammatory models. Based on this study, we confirmed that Citrullus colocynthis Schrad. is a potentially useful drug suitable for further evaluation for rheumatoid arthritis, and its folk medicinal use as an analgesic and anti-inflammatory agents is validated. Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.

  18. 75 FR 65385 - Agency Information Collection Activities: Proposed Collection; Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-22

    ... resources; (3) strengths and weaknesses of program design and implementation; (4) costs and benefits of the... collected from NEES leaders and researchers regarding: (1) The current capabilities of the NEES network... Burden Hours Requested: 87. The annualized cost to respondents is estimated at: $3,387.78. There are...

  19. Environmental variation is directly responsible for short- but not long-term variation in forest-atmosphere carbon exchange

    Treesearch

    Andrew D. Richardson; David Y. Hollinger; John D. Aber; Scott V. Ollinger; Bobby H. Braswell

    2007-01-01

    Tower-based eddy covariance measurements of forest-atmosphere carbon dioxide (CO2) exchange from many sites around the world indicate that there is considerable year-to-year variation in net ecosystem exchange (NEE). Here, we use a statistical modeling approach to partition the interannual variability in NEE (and its component fluxes, ecosystem...

  20. Pan-Arctic modelling of net ecosystem exchange of CO2.

    PubMed

    Shaver, G R; Rastetter, E B; Salmon, V; Street, L E; van de Weg, M J; Rocha, A; van Wijk, M T; Williams, M

    2013-08-19

    Net ecosystem exchange (NEE) of C varies greatly among Arctic ecosystems. Here, we show that approximately 75 per cent of this variation can be accounted for in a single regression model that predicts NEE as a function of leaf area index (LAI), air temperature and photosynthetically active radiation (PAR). The model was developed in concert with a survey of the light response of NEE in Arctic and subarctic tundras in Alaska, Greenland, Svalbard and Sweden. Model parametrizations based on data collected in one part of the Arctic can be used to predict NEE in other parts of the Arctic with accuracy similar to that of predictions based on data collected in the same site where NEE is predicted. The principal requirement for the dataset is that it should contain a sufficiently wide range of measurements of NEE at both high and low values of LAI, air temperature and PAR, to properly constrain the estimates of model parameters. Canopy N content can also be substituted for leaf area in predicting NEE, with equal or greater accuracy, but substitution of soil temperature for air temperature does not improve predictions. Overall, the results suggest a remarkable convergence in regulation of NEE in diverse ecosystem types throughout the Arctic.

  1. Impact of precipitation dynamics on net ecosystem exchange

    USDA-ARS?s Scientific Manuscript database

    Net ecosystem carbon dioxide (CO2) exchange (NEE) was measured on shortgrass steppe (SGS) vegetation at the USDA Central Plains Experimental Range in northeastern Colorado from 2001-2003. Large year-to-year differences were observed in annual NEE, with > 95% of the net carbon uptake occurring during...

  2. Carbon fluxes on North American rangelands

    Treesearch

    Tony Svejcar; Raymond Angell; James A. Bradford; William Dugas; William Emmerich; Albert B. Frank; Tagir Gilmanov; Marshall Haferkamp; Douglas A. Johnson; Herman Mayeux; Pat Mielnick; Jack Morgan; Nicanor Z. Saliendra; Gerald E. Schuman; Phillip L. Sims; Kereith Snyder

    2008-01-01

    Rangelands account for almost half of the earth's land surface and may play an important role in the global carbon (C) cycle. We studied net ecosystem exchange (NEE) of C on eight North American rangeland sites over a 6-yr period. Management practices and disturbance regimes can influence NEE; for consistency, we compared ungrazed and undisturbed rangelands...

  3. Biologically-Effective Rainfall Pulses in Mediterranean and Monsoonal Regions

    USDA-ARS?s Scientific Manuscript database

    In semiarid regions rainfall pulses provide intermittent opportunities for biological activity. These pulses have been shown to affect the activity of microbes and plant differently, altering the net ecosystem exchange of carbon dioxide (NEE) from these ecosystems. We examine NEE and its components ...

  4. Reconciling estimates of the contemporary North American carbon balance among terrestrial biosphere models, atmospheric inversions, and a new approach for estimating net ecosystem exchange from inventory-based data

    Treesearch

    Daniel J. Hayes; David P. Turner; Graham Stinson; A. David Mcguire; Yaxing Wei; Tristram O. West; Linda S. Heath; Bernardus Dejong; Brian G. McConkey; Richard A. Birdsey; Werner A. Kurz; Andrew R. Jacobson; Deborah N. Huntzinger; Yude Pan; W. Mac Post; Robert B. Cook

    2012-01-01

    We develop an approach for estimating net ecosystem exchange (NEE) using inventory-based information over North America (NA) for a recent 7-year period (ca. 2000-2006). The approach notably retains information on the spatial distribution of NEE, or the vertical exchange between land and atmosphere of all non-fossil fuel sources and sinks of CO2,...

  5. Estimation of Net Ecosystem Carbon Exchange for the Conterminous UnitedStates by Combining MODIS and AmeriFlux Data

    SciTech Connect

    Xiao, Jingfeng; Zhuang, Qianlai; Baldocchi, Dennis D.; Law, Beverly E.; Richardson, Andrew D.; Chen, Jiquan; Oren, Ram; Starr, Gregory; Noormets, Asko; Ma, Siyan; Verma, Shashi B.; Wharton, Sonia; Wofsy, Steven C.; Bolstad, Paul V.; Burns, Sean P.; Cook, David R.; Curtis, Peter S.; Drake, Bert G.; Falk, Matthias; Fischer, Marc L.; Foster, David R.; Gu, Lianhong; Hadley, Julian L.; Hollinger, David Y.; Katul, Gabriel G.; Litvak, Marcy; Martin, Timothy A.; Matamala, Roser; McNulty, Steve; Meyers, Tilden P.; Monson, Russell K.; Munger, J. William; Oechel, Walter C.; U, Kyaw Tha Paw; Schmid, Hans Peter; Scott, Russell L.; Sun, Ge; Suyker, Andrew E.; Torn, Margaret S.

    2009-03-06

    Eddy covariance flux towers provide continuous measurements of net ecosystem carbon exchange (NEE) for a wide range of climate and biome types. However, these measurements only represent the carbon fluxes at the scale of the tower footprint. To quantify the net exchange of carbon dioxide between the terrestrial biosphere and the atmosphere for regions or continents, flux tower measurements need to be extrapolated to these large areas. Here we used remotely-sensed data from the Moderate Resolution Imaging Spectrometer (MODIS) instrument on board NASA's Terra satellite to scale up AmeriFlux NEE measurements to the continental scale. We first combined MODIS and AmeriFlux data for representative U.S. ecosystems to develop a predictive NEE model using a regression tree approach. The predictive model was trained and validated using NEE data over the periods 2000-2004 and 2005-2006, respectively. We found that the model predicted NEE reasonably well at the site level. We then applied the model to the continental scale and estimated NEE for each 1 km x 1 km cell across the conterminous U.S. for each 8-day period in 2005 using spatially-explicit MODIS data. The model generally captured the expected spatial and seasonal patterns of NEE. Our study demonstrated that our empirical approach is effective for scaling up eddy flux NEE measurements to the continental scale and producing wall-to-wall NEE estimates across multiple biomes. Our estimates may provide an independent dataset from simulations with biogeochemical models and inverse modeling approaches for examining the spatiotemporal patterns of NEE and constraining terrestrial carbon budgets for large areas.

  6. Estimation of net ecosystem carbon exchange for the conterminous United States by combining MODIS and AmeriFlux data

    SciTech Connect

    Xiao, Jingfeng; Zhuang, Qianlai; Baldocchi, Dennis D.; Bolstad, Paul V.; Burns, Sean P.; Chen, Jiquan; Cook, David R.; Curtis, Peter S.; Drake, Bert G.; Foster, David R.; Gu, Lianhong; Hadley, Julian L.; Hollinger, David Y.; Katul, Gabriel G.; Law, Beverly E.; Litvak, Marcy; Ma, Siyan; Martin, Timothy A.; Matamala, Roser; McNulty, Steve; Meyers, Tilden P.; Monson, Russell K.; Munger, J. William; Noormets, Asko; Oechel, Walter C.; Oren, Ram; Richardson, Andrew D.; Schmid, Hans Peter; Scott, Russell L.; Starr, Gregory; Sun, Ge; Suyker, Andrew E.; Torn, Margaret S.; Paw, Kyaw; Verma, Shashi B.; Wharton, Sonia; Wofsy, Steven C.

    2008-10-01

    Eddy covariance flux towers provide continuous measurements of net ecosystem carbon exchange (NEE) for a wide range of climate and biome types. However, these measurements only represent the carbon fluxes at the scale of the tower footprint. To quantify the net exchange of carbon dioxide between the terrestrial biosphere and the atmosphere for regions or continents, flux tower measurements need to be extrapolated to these large areas. Here we used remotely sensed data from the Moderate Resolution Imaging Spectrometer (MODIS) instrument on board the National Aeronautics and Space Administration's (NASA) Terra satellite to scale up AmeriFlux NEE measurements to the continental scale. We first combined MODIS and AmeriFlux data for representative U.S. ecosystems to develop a predictive NEE model using a modified regression tree approach. The predictive model was trained and validated using eddy flux NEE data over the periods 2000-2004 and 2005-2006, respectively. We found that the model predicted NEE well (r = 0.73, p < 0.001). We then applied the model to the continental scale and estimated NEE for each 1 km x 1 km cell across the conterminous U.S. for each 8-day interval in 2005 using spatially explicit MODIS data. The model generally captured the expected spatial and seasonal patterns of NEE as determined from measurements and the literature. Our study demonstrated that our empirical approach is effective for scaling up eddy flux NEE measurements to the continental scale and producing wall-to-wall NEE estimates across multiple biomes. Our estimates may provide an independent dataset from simulations with biogeochemical models and inverse modeling approaches for examining the spatiotemporal patterns of NEE and constraining terrestrial carbon budgets over large areas.

  7. Seasonal and interannual variations of carbon exchange over a rice-wheat rotation system on the North China Plain

    NASA Astrophysics Data System (ADS)

    Chen, Chen; Li, Dan; Gao, Zhiqiu; Tang, Jianwu; Guo, Xiaofeng; Wang, Linlin; Wan, Bingcheng

    2015-10-01

    Rice-wheat (R-W) rotation systems are ubiquitous in South and East Asia, and play an important role in modulating the carbon cycle and climate. Long-term, continuous flux measurements help in better understanding the seasonal and interannual variation of the carbon budget over R-W rotation systems. In this study, measurements of CO2 fluxes and meteorological variables over an R-W rotation system on the North China Plain from 2007 to 2010 were analyzed. To analyze the abiotic factors regulating Net Ecosystem Exchange (NEE), NEE was partitioned into gross primary production (GPP) and ecosystem respiration. Nighttime NEE or ecosystem respiration was controlled primarily by soil temperature, while daytime NEE was mainly determined by photosythetically active radiation (PAR). The responses of nighttime NEE to soil temperature and daytime NEE to light were closely associated with crop development and photosynthetic activity, respectively. Moreover, the interannual variation in GPP and NEE mainly depended on precipitation and PAR. Overall, NEE was negative on the annual scale and the rotation system behaved as a carbon sink of 982 g C m-2 per year over the three years. The winter wheat field took up more CO2 than the rice paddy during the longer growing season, while the daily NEE for wheat and rice were -2.35 and -3.96 g C m-2, respectively. After the grain harvest was subtracted from the NEE, the winter wheat field became a moderately strong carbon sink of 251-334 g C m-2 per season, whereas the rice paddy switched to a weak carbon sink of 107-132 per season.

  8. Estimation of net ecosystem carbon exchange for the conterminous United States by combining MODIS and AmeriFlux data

    SciTech Connect

    Xiao, Jingfeng; Zhuang, Qianlai; Baldocchi, Dennis; Ma, Siyan; Law, Beverly E.; Richardson, Andrew D; Chen, Jiquan; Oren, Ram

    2008-10-01

    Eddy covariance flux towers provide continuous measurements of net ecosystem carbon exchange (NEE) for a wide range of climate and biome types. However, these measurements only represent the carbon fluxes at the scale of the tower footprint. To quantify the net exchange of carbon dioxide between the terrestrial biosphere and the atmosphere for regions or continents, flux tower measurements need to be extrapolated to these large areas. Here we used remotely sensed data from the Moderate Resolution Imaging Spectrometer (MODIS) instrument on board the National Aeronautics and Space Administration s (NASA) Terra satellite to scale up AmeriFlux NEE measurements to the continental scale.We first combined MODIS and AmeriFlux data for representative U.S. ecosystems to develop a predictive NEE model using a modified regression tree approach. The predictive model was trained and validated using eddy flux NEE data over the periods 2000 2004 and 2005 2006, respectively. We found that the model predicted NEE well (r = 0.73, p < 0.001). We then applied the model to the continental scale and estimated NEE for each 1 km 1 km cell across the conterminous U.S. for each 8-day interval in 2005 using spatially explicit MODIS data. The model generally captured the expected spatial and seasonal patterns of NEE as determined from measurements and the literature. Our study demonstrated that our empirical approach is effective for scaling up eddy flux NEE measurements to the continental scale and producing wall-to-wall NEE estimates across multiple biomes. Our estimates may provide an independent dataset from simulations with biogeochemical models and inverse modeling approaches for examining the spatiotemporal patterns of NEE and constraining terrestrial carbon budgets over large areas.

  9. Relative linkages of climatic and environmental drivers/fluxes with net ecosystem exchanges of six diverse terrestrial ecosystems

    NASA Astrophysics Data System (ADS)

    Abdul-Aziz, O.; Ishtiaq, K. S.

    2013-12-01

    We analyzed ecosystem-scale, half-hourly net ecosystem exchange (NEE) data along with the environmental drivers and heat fluxes for six distinct ecosystems of the AmeriFlux network. Multivariate pattern recognition techniques such as Principal Component Analysis (PCA) and Factor Analysis (FA) were applied to investigate potential groupings in participatory variables and their relative linkages. Normalized multiple regression models were developed in order to extract the statistically significant predictors of NEE from the data matrix and compute their relative weights. Radiation components (net radiation and photosynthetically active radiation) along with the ecosystem water and energy fluxes (latent and soil heat fluxes) displayed dictating weights on NEE followed by temperature related variables (air temperature, soil temperature and vapor pressure deficit). Velocity factors (wind speed and friction velocity) were less explanatory in describing the half hourly fluxes of NEE. Developed linear models showed acceptable accuracy (ratio of root mean square error to observations' standard deviation, RSR: 0.48-0.68) and fitting efficiency (coefficient of determination, R2: 0.54-0.77) in explaining NEE. Overall, environmental drivers and fluxes showed relatively analogous association with NEE among the six separate ecoregions representing diversity in climate, hydrology, and vegetation types. The findings can guide the development of appropriate mechanistic and empirical models for spatio-temporally robust predictions of NEE and potential carbon sequestration from diverse terrestrial ecosystems.

  10. Carbon dioxide fluxes of an urban tidal marsh in the Hudson-Raritan estuary

    NASA Astrophysics Data System (ADS)

    Schäfer, K. V. R.; Tripathee, R.; Artigas, F.; Morin, T. H.; Bohrer, G.

    2014-11-01

    Net ecosystem exchange (NEE) of tidal brackish wetlands in urban areas is largely unknown, albeit it is an important ecosystem service. High carbon dioxide (CO2) uptake of estuaries can potentially be achieved by creating conditions that foster CO2 uptake and sequestration. Thus, this study sought to assess NEE in a mesohaline tidal urban wetland that has been restored and determine the biophysical drivers of NEE in order to investigate uptake strength and drivers thereof. Beginning in 2009, NEE was measured using the eddy covariance technique in a restored urban estuarine wetland. Maximum NEE rates observed were -30 µmol m-2 s-1 under high light conditions in the summer. Monthly mean NEE showed this ecosystem to be a CO2 source in the winter, but a CO2 sink in summer. Conditional Granger causality showed the influence of net radiation on half daily to biweekly timescales on NEE and the influence of water level at half daily time scales. The overall productivity of this wetland is within the expected range of tidal brackish marshes and it was a sink for atmospheric CO2 in two out of the 3 years of this study and had a continued increase over the study period.

  11. Contemporary mire net ecosystem green-house gas balance: controls and susceptibility to change

    NASA Astrophysics Data System (ADS)

    Nilsson, Mats; Eriksson, Tobias; Grelle, Achim; Larsson, Anna; Laudon, Hjalmar; Lindroth, Anders; Ottosson-Löfvenius, Mikaell; Peichl, Matthias; Sagerfors, Jörgen; Ågren, Anneli; Öquist, Mats

    2015-04-01

    In this presentation I will address three main issues: 1 - What is the contemporary carbon sequestration function of high latitude mire ecosystems relative to Holocene average? 2 - The relative importance of the component carbon (C) fluxes for the annual mire Net Ecosystem Carbon Balance (NECB); 3 - The importance of gross primary production (GPP) versus ecosystem respiration (Reco) for the annual Net Ecosystem Exchange (NEE); The annual boreal mire NECB is made up principally by the biosphere-atmosphere exchange of CO2 (NEE) and CH4 and the runoff C-export. One important research issue is to further understand what controls the relative contribution from the component fluxes to the annual mire NECB. A second important major research issue is to reveal the relative importance of gross photosynthesis (GPP) and ecosystem respiration (Reco) respectively for the annual mire NEE. The relative importance of GPP and Reco respectively for the NECB also encounters the effect of changes in the lengths of the growing season and non-growing season respectively. In this presentation we use ten years of data on annual fluxes of NEE, methane and water discharge C export at a nutrient poor minerogenic boreal mire, Degerö Stormyr, in northern Sweden to address the above questions. Winter time NEE together with methane emission and water discharge C export reduces the growing season NEE with approximately 60%, thus substantially controlling the annual boreal mire NEE.

  12. Voltammetry of redox analytes at trace concentrations with nanoelectrode ensembles.

    PubMed

    Moretto, Ligia Maria; Pepe, Niki; Ugo, Paolo

    2004-04-19

    Gold nanoelectrodes ensembles (NEEs) have been prepared by electroless plating of Au nanoelectrode elements within the pores of a microporous polycarbonate template membrane. Cyclic voltammograms recorded in (ferrocenylmethyl) trimethylammonium hexafluorophosphate (FA(+) PF(6)(-)) solutions showed that these NEEs operate in the "total-overlap" response regime, giving well resolved peak shaped voltammograms. Experimental results show that the faradaic/background currents ratios at the NEE are independent on the total geometric area of the ensemble, so that NEE can be enlarged or miniaturized at pleasure without influencing the very favorable signal/noise ratio. Differential pulse voltammetry (DPV) at the NEE is optimized for direct determinations at trace levels. DPV at NEE allowed the determination (with no preconcentration) of trace amounts of FA(+), with a detection limit of 0.02muM. The use of NEE and DPV in cytochrome c (cyt c) solutions showed the possibility to observe the direct electrochemistry of submicromolar concentration of the protein, even without the need of adding any promoter or mediator.

  13. Elevated CO(2) and temperature alter net ecosystem C exchange in a young Douglas fir mesocosm experiment.

    PubMed

    Tingey, David T; Lee, E Henry; Phillips, Donald L; Rygiewicz, Paul T; Waschmann, Ronald S; Johnson, Mark G; Olszyk, David M

    2007-11-01

    We investigated the effects of elevated CO(2) (EC) [ambient CO(2) (AC) + 190 ppm] and elevated temperature (ET) [ambient temperature (AT) + 3.6 degrees C] on net ecosystem exchange (NEE) of seedling Douglas fir (Pseudotsuga menziesii) mesocosms. As the study utilized seedlings in reconstructed soil-litter-plant systems, we anticipated greater C losses through ecosystem respiration (R(e)) than gains through gross photosynthesis (GPP), i.e. negative NEE. We hypothesized that: (1) EC would increase GPP more than R(e), resulting in NEE being less negative; and (2) ET would increase R(e) more than GPP, resulting in NEE being more negative. We also evaluated effects of CO(2) and temperature on light inhibition of dark respiration. Consistent with our hypothesis, NEE was a smaller C source in EC, not because EC increased photosynthesis but rather because of decreased respiration resulting in less C loss. Consistent with our hypothesis, NEE was more negative in ET because R(e) increased more than GPP. The light level that inhibited respiration varied seasonally with little difference among CO(2) and temperature treatments. In contrast, the degree of light inhibition of respiration was greater in AC than EC. In our system, respiration was the primary control on NEE, as EC and ET caused greater changes in respiration than photosynthesis.

  14. Net Ecosystem Exchange of CO2 with Rapidly Changing High Arctic Landscapes

    NASA Astrophysics Data System (ADS)

    Emmerton, C. A.

    2015-12-01

    High Arctic landscapes are expansive and changing rapidly. However our understanding of their functional responses and potential to mitigate or enhance anthropogenic climate change is limited by few measurements. We collected eddy covariance measurements to quantify the net ecosystem exchange (NEE) of CO2 with polar semidesert and meadow wetland landscapes at the highest-latitude location measured to date (82°N). We coupled these rare data with ground and satellite vegetation production measurements (Normalized Difference Vegetation Index; NDVI) to evaluate the effectiveness of upscaling local to regional NEE. During the growing season, the dry polar semidesert landscape was a near zero sink of atmospheric CO2 (NEE: -0.3±13.5 g C m-2). A nearby meadow wetland accumulated over two magnitudes more carbon (NEE: -79.3±20.0 g C m-2) than the polar semidesert landscape, and was similar to meadow wetland NEE at much more southern latitudes. Polar semidesert NEE was most influenced by moisture, with wetter surface soils resulting in greater soil respiration and CO2 emissions. At the meadow wetland, soil heating enhanced plant growth, which in turn increased CO2 uptake. Our upscaling assessment found that polar semidesert NDVI measured on site was low (mean: 0.120-0.157) and similar to satellite measurements (mean: 0.155-0.163). However, weak plant growth resulted in poor satellite NDVI-NEE relationships and created challenges for remotely-detecting changes in the cycling of carbon on the polar semidesert landscape. The meadow wetland appeared more suitable to assess plant production and NEE via remote-sensing, however high Arctic wetland extent is constrained by topography to small areas that may be difficult to resolve with large satellite pixels. We predict that until summer precipitation and humidity increases substantially, climate-related changes of dry high Arctic landscapes may be restricted by poor soil moisture retention, and therefore have some inertia against

  15. Comparing independent estimates of carbon dioxide exchange over 5 years at a deciduous forest in the southeastern United States

    NASA Astrophysics Data System (ADS)

    Wilson, Kell B.; Baldocchi, Dennis D.

    2001-12-01

    At a deciduous forest in the southeast United States (Walker Branch Watershed, Oak Ridge, Tennessee), as at other sites with tall vegetation and/or complex terrain, it is difficult to temporally integrate eddy covariance data to obtain long-term estimates of net ecosystem exchange of carbon dioxide (NEE), primarily because of suspected systematic nocturnal errors. Therefore, although eddy covariance data can be invaluable, additional tools such as empirical gap-filling methods, independent measurements of CO2 flux using chambers, and simulations using canopy process models are often necessary to obtain reliable annual carbon uptake estimates. Two independent approaches for estimating annual NEE using these tools at the Walker Branch site are discussed. One approach is to cumulatively sum the full set of eddy covariance measurements over time. The second approach is to sum the output of NEE from a biophysical canopy exchange model (CANOAK). CANOAK incorporates independent chamber measurements on leaves, soil, and stems and is driven using the observed canopy architecture, meteorology, soil water content, and soil temperatures to predict NEE. Both methods estimate similar trends and magnitudes of daytime (daylight hours) soil respiration and NEE over 5 years. Both methods also suggest similar differences among years (interannual variability). These two estimates of NEE are used to address possible measurement bias errors at this site and to provide plausible estimates of annual NEE. The estimated mean annual NEE at this site is -574 g C m-2 yr-1 between 1995 and 1999, ranging from -470 g C m-2 y-1 (1995) to -629 g C m-2 yr-1 (1999) (negative NEE indicates uptake by forest).

  16. Disentangling the confounding effects of PAR and air temperature on net ecosystem exchange in time and scale

    NASA Astrophysics Data System (ADS)

    yang, Z.; Chen, J.; Becker, R.; Chu, H.; Xie, J.; Shao, C.

    2013-12-01

    Net ecosystem exchange of CO2 (NEE) in temperate forests is modulated by microclimatic factors. The effects of those factors differ at different time scales and during different time periods. Some of them are correlated across a number of time scales, so their effects on NEE are confounded by each other. PAR and air temperature (Ta) are among the two most important drivers of NEE in temperate forests, and among the two most correlated microclimatic factors. PAR and Ta have similar daily, seasonal, and annual cycles. Their influence on NEE is confounded by each other and entangled together especially at those scales. In this study, we tried to disentangle the confounding effects of them on NEE at different time scales and during different time periods. To accomplish this objective, we applied the innovative spectral analysis techniques including Continuous Wavelet Transformation (CWT), Cross Wavelet Transformation (XWT), Wavelet Coherent (WTC), and Partial Wavelet Coherence (PWC) on seven years time series (2004-2010) of PAR, Ta and NEE from the Ohio Oak Openings site (N 41.5545°, W 83.8438°), USA for spectral analysis. We found that PAR is the major driver at short time scales (e.g. semidiurnal and daily) and Ta is the major driver at long time scales (e.g. seasonal and annual). At daily scale during growing seasons, PAR is anti-phase with NEE with no time delay while Ta lagged PAR about 2-3 hours, which could be explained by the strong dependence of photosynthesis on PAR and a 2-3 hours lags of the daily course of Ta to PAR. At daily scale during non-growing season, NEE has little variation and thus neither Ta nor PAR has high common wavelet power and significant coherence with NEE. At annual scale, Ta is anti-phase with NEE and PAR leads NEE about 34 days, which could be explained by the strong dependence of LAI dynamics on Ta and the lag between the LAI/biomass development and the progress of sunlight. We also found that NEE distributes most of its variation

  17. Reproduction of Meloidogyne marylandi and M. incognita on several Poaceae.

    PubMed

    Faske, T R; Starr, J L

    2009-03-01

    The susceptibility of 22 plant species to Meloidogyne marylandi and M. incognita was examined in three greenhouse experiments. Inoculum of M. marylandi was eggs from cultures maintained on Zoysia matrella "Cavalier" or Cynodon dactylon x C. trasvaalensis "Tifdwarf". Inoculum of M. incognita was eggs from cultures maintained on Solanum lycopersicum 'Rutgers'. In each host test the inoculum density was 2,000 nematode eggs/pot. None of the three dicot species tested (Gossypium hirsutum, Arachis hypogaea, and S. lycopersicum) were hosts for M. marylandi but, as expected, M. incognita had high levels of reproduction on G. hirsutum and S. lycopersicum. Meloidogyne marylandi reproduced on all of the 19 grass species (Poaceae) tested but reproduction varied greatly (P = 0.05) among these hosts. The following grasses were identified for the first time as hosts for M. marylandi: Buchloe dactyloides (buffalograss), Echinochloa colona (jungle rice), Eragostis curvula (weeping lovegrass), Paspalum dilatatum (dallisgrass), P. notatum (bahiagrass), Sorghastrum, nutans (indiangrass), Tripsacum dactyloides (eastern gamagrass), and Zoysia matrella (zoysiagrass). No reproduction of M. incognita was observed on B. dactyloides, Cyndon dactylon (common bermudagrass), E. curvula, P. vaginatum (seashore paspalum), S. nutans, T. dactyloides, Z. matrella or Z. japonica. Reproduction of M. incognita was less than reproduction of M. marylandi on the other grass species, except for the Zea mays inbred line B73 on which M. incognita had greater reproduction than did M. marylandi (P = 0.05) and Stenotaphrum secundatum (St. Augustinegrass) on which M. incognita and M. marylandi had similar levels of reproduction.

  18. Regional scaling of soil moisture dynamics on the semiarid grasslands of Mexico through remotely sensed vegetation indices

    NASA Astrophysics Data System (ADS)

    Carrera-Hernandez, J. J.; Mata-Martinez, A.; Huber-Sannwald, E.; Arredondo, T.

    2014-12-01

    Soil moisture dynamics for both native (Bouteloa gracilis) and introduced (Eragrostis curvula) species within the semiarid grasslands in Mexico are analyzed. The semiarid grasslands of Mexico are part of the shortgrass steppe ecosystem, which extends from the North American midwest in the north to Llanos de Ojuelos in the south, where the study site is located. Soil moisture dynamics are measured on two homogeneous fields; one dominated by the native species (Bouteloa gracilis), and another with an introduced species (Eragrostis curvula) at three different depths with high temporal resolution along with standard climatological data. These data are related to measured Leaf Area Index (LAI) and spectra at 16 different wavelengths, both of which, in turn, are related to remotely sensed imagery through different vegetation indices (NDVI, SAVI, EVI and Modified Chlorophyll Absorption Ratio Index (MCARI)) for different sensors (LANDSAT, SPOT, Pleiades) at different growth stages. To date, the MCARI exhibits a larger correlation with LAI for all sensors and growing stages for both grass species (ongoing field work will provide additional data). Regionalization of soil moisture dynamics (i.e. recharge) will be done using a numerical model of the vadose zone that will be linked to the temporal variation of MCARI. Financial support by the Mexico's CONACYT (project CB 158370) and UNAM's PAPIIT program (project IA100613) is acknowledged.

  19. Aquatic hyphomycete communities associated with decomposing alder leaf litter in reference headwater streams of the Basque Country (northern Spain).

    PubMed

    Pérez, Javier; Descals, Enrique; Pozo, Jesús

    2012-08-01

    The community of aquatic hyphomycetes associated with decomposing alder leaf litter was studied during autumn-winter in nine headwater reference streams of the Basque Country (northern Spain). In order to study the spatial variability in composition and community structure, three streams from each of three different river basins were compared. The colonization dynamics and community changes throughout the decomposition process were also followed in three of the rivers (one per basin). The taxonomic richness and community structure of these fungi varied among rivers, including similar streams of a given watershed. However, neither species diversity nor total abundance was statistically related to environmental variables. Only the conidial production of two of the species, Flagellospora curvula and Lunulospora curvula appeared to be enhanced by nitrate availability in the water. The taxonomic richness and the reproductive activity (sporulation rate) were positively related to the leaf litter decomposition rate. The changes in conidial production along the process were similar for all the streams and helped explain leaf litter quality dynamics.

  20. Postia alni Niemelä & Vampola (Basidiomycota, Polyporales) – member of the problematic Postia caesia complex – has been found for the first time in Hungary

    PubMed Central

    2014-01-01

    Abstract Due to their bluish basidiocarps the Postia caesia (syn. Oligoporus caesius) complex forms a distinctive morphological group within the polypore genus Postia Fr., 1874. Five species of this group occur in Europe: Postia alni Niemelä & Vampola, Postia caesia (Schrad.) P. Karst., Postia luteocaesia (A. David) Jülich, Postia mediterraneocaesia M. Pierre & B. Rivoire and Postia subcaesia (A. David) Jülich. In this study Postia alni is reported for the first time from Hungary. The dichotomous key of the species of the European Postia caesia complex was prepared as well. PMID:24855437

  1. Superoxide Free Radicals Are Produced in Glyoxysomes 1

    PubMed Central

    Sandalio, Luisa M.; Fernández, Victor M.; Rupérez, Francisco L.; Del Río, Luis A.

    1988-01-01

    The production of superoxide free radicals in pellet and supernatant fractions of glyoxysomes, specialized plant peroxisomes from watermelon (Citrullus vulgaris Schrad.) cotyledons, was investigated. Upon inhibition of the endogenous superoxide dismutase, xanthine, and hypoxanthine induced in glyoxysomal supernatants the generation of O2− radicals and this was inhibited by allopurinol. In glyoxysomal pellets, NADH stimulated the generation of superoxide radicals. Superoxide production by purines was due to xanthine oxidase, which was found predominantly in the matrix of glyoxysomes. The generation of O2− radicals in glyoxysomes by endogenous metabolites suggests new active oxygen-related roles for glyoxysomes, and for peroxisomes in general, in cellular metabolism. PMID:16666081

  2. Estimation of Carbon Flux of Forest Ecosystem over Qilian Mountains by BIOME-BGC Model

    NASA Astrophysics Data System (ADS)

    Yan, Min; Tian, Xin; Li, Zengyuan; Chen, Erxue; Li, Chunmei

    2014-11-01

    The gross primary production (GPP) and net ecosystem exchange (NEE) are important indicators for carbon fluxes. This study aims at evaluating the forest GPP and NEE over the Qilian Mountains using meteorological, remotely sensed and other ancillary data at large scale. To realize this, the widely used ecological-process-based model, Biome-BGC, and remote-sensing-based model, MODIS GPP algorithm, were selected for the simulation of the forest carbon fluxes. The combination of these two models was based on calibrating the Biome-BGC by the optimized MODIS GPP algorithm. The simulated GPP and NEE values were evaluated against the eddy covariance observed GPPs and NEEs, and the well agreements have been reached, with R2=0.76, 0.67 respectively.

  3. Stress and Hair Loss: Are They Related?

    MedlinePlus

    ... hair. Trichotillomania. Trichotillomania (trik-o-til-o-MAY-nee-uh) is an irresistible urge to pull out ... Flavin, M.D. References Shapiro J, et al. Evaluation and diagnosis of hair loss. http://www.uptodate. ...

  4. Estimation of Carbon Flux of Forest Ecosystem over Qilian Mountains by BIOME-BGC Model

    NASA Astrophysics Data System (ADS)

    Yan, Min; Tian, Xin; Li, Zengyuan; Chen, Erxue; Li, Chunmei

    2014-11-01

    The gross primary production (GPP) and net ecosystem exchange (NEE) are important indicators for carbon fluxes. This study aims at evaluating the forest GPP and NEE over the Qilian Mountains using meteorological, remotely sensed and other ancillary data at large scale. To realize this, the widely used ecological-process- based model, Biome-BGC, and remote-sensing-based model, MODIS GPP algorithm, were selected for the simulation of the forest carbon fluxes. The combination of these two models was based on calibrating the Biome-BGC by the optimized MODIS GPP algorithm. The simulated GPP and NEE values were evaluated against the eddy covariance observed GPPs and NEEs, and the well agreements have been reached, with R2=0.76, 0.67 respectively.

  5. Validation Of DEM Data Dvied From World View 3 Stero Imagery For Low Elevation Majuro Atoll, Marchall Islands

    EPA Science Inventory

    The availability of surface elevation data for the Marshall Islands has been identified as a "massive" data gap for conducting vulnerability assessments and the subsequent development of climate change adaption strategies. Specifically, digital elevation model (DEM) data are nee...

  6. Nonlinear Waves in Waveguides

    NASA Astrophysics Data System (ADS)

    Leble, Sergei B.

    S.B. Leble's book deals with nonlinear waves and their propagation in metallic and dielectric waveguides and media with stratification. The underlying nonlinear evolution equations (NEEs) are derived giving also their solutions for specific situations. The reader will find new elements to the traditional approach. Various dispersion and relaxation laws for different guides are considered as well as the explicit form of projection operators, NEEs, quasi-solitons and of Darboux transforms. Special points relate to: 1. the development of a universal asymptotic method of deriving NEEs for guide propagation; 2. applications to the cases of stratified liquids, gases, solids and plasmas with various nonlinearities and dispersion laws; 3. connections between the basic problem and soliton- like solutions of the corresponding NEEs; 4. discussion of details of simple solutions in higher- order nonsingular perturbation theory.

  7. Nonlinear Waves in Waveguides with Stratification.

    NASA Astrophysics Data System (ADS)

    Leble, Sergei B.

    S.B. Leble's book deals with nonlinear waves and their propagation in metallic and dielectric waveguides and media with stratification. The underlying nonlinear evolution equations (NEEs) are derived giving also their solutions for specific situations. The reader will find new elements to the traditional approach. Various dispersion and relaxation laws for different guides are considered as well as the explicit form of projection operators, NEEs, quasi-solitons and of Darboux transforms. Special points relate to: 1. the development of a universal asymptotic method of deriving NEEs for guide propagation; 2. applications to the cases of stratified liquids, gases, solids and plasmas with various nonlinearities and dispersion laws; 3. connections between the basic problem and soliton- like solutions of the corresponding NEEs; 4. discussion of details of simple solutions in higher- order nonsingular perturbation theory.

  8. What Causes Thrombocythemia and Thrombocytosis?

    MedlinePlus

    ... With Clinical Trials Links Related Topics Hemolytic Anemia Iron-Deficiency Anemia Stroke Von Willebrand Disease Send a link ... that can cause a high platelet count are: Iron-deficiency anemia (uh-NEE-me-uh) Hemolytic (HEE-moh- ...

  9. Validation Of DEM Data Dvied From World View 3 Stero Imagery For Low Elevation Majuro Atoll, Marchall Islands

    EPA Science Inventory

    The availability of surface elevation data for the Marshall Islands has been identified as a "massive" data gap for conducting vulnerability assessments and the subsequent development of climate change adaption strategies. Specifically, digital elevation model (DEM) data are nee...

  10. Jock Itch

    MedlinePlus

    ... of a group of fungal skin infections called tinea. The medical name for jock itch is tinea cruris (pronounced: TIH-nee-uh KRUR-us). Jock itch, like other tinea infections, is caused by several types of mold- ...

  11. APPLICATIONS OF A CONCEPTUAL MODEL (THE BIOLOGICAL CONDITION GRADIENT) TO DEFINE AQUATIC REFERENCE CONDITIONS

    EPA Science Inventory

    The United States Clean Water Act currently offers no definitions to interpret the Act's objective to "restore and maintain physical, chemical and biological integrity of the Nation's waters". Operative definitions, independent of differences in assessment methodologies, are nee...

  12. Host ranges of gregarious muscoid fly parasitoids: Muscidifurax raptorellus (Kogan and Legner) (Hymenoptera:Pteromalidae), Tachinaephagus zealandicus Ashmead (Hymenoptera: Encyrtidae), and Trichopria (Hymenoptera: Diapriidae)

    USDA-ARS?s Scientific Manuscript database

    Attack rates, progeny production, sex ratios and host utilization efficiency of Muscidifurax raptorellus (Kogan and Legner) (Hymenoptera: Pteromalidae), Tachinaephagus zealandicus Ashmead (Hymenoptera: Encyrtidae), and Trichopria nigra (Nees) (Hymenoptera: Diapriidae) were evaluated in laboratory bi...

  13. Blood

    MedlinePlus

    ... that die or are lost from the body. White Blood Cells White blood cells (WBCs, and also ... of severe pain. previous continue Diseases of the White Blood Cells Neutropenia (pronounced: new-truh-PEE-nee- ...

  14. DEVELOPMENT OF REAL-TIME SITE-SPECIFIC MICROSCALE EMISSION FACTOR MODEL FOR THE ASSESSMENT OF HUMAN EXPOSURE TO MOTOR VEHICLE EMISSIONS

    EPA Science Inventory

    The United States Environmental Protection Agency's (EPA) National Expsoure Research Laboratory (NERL) has initiated a project to improve the methodology for modeling urban-scale human exposure to mobile source emissions. The modeling project has started by considering the nee...

  15. What Is Aplastic Anemia?

    MedlinePlus

    ... from the NHLBI on Twitter. What Is Aplastic Anemia? Aplastic anemia (a-PLAS-tik uh-NEE-me-uh) is ... heart, heart failure , infections, and bleeding. Severe aplastic anemia can even cause death. Overview Aplastic anemia is ...

  16. Ringworm

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Ringworm KidsHealth > For Teens > Ringworm Print A A A ... is generally easy to treat. The Basics on Tinea Infections Tinea (pronounced: TIH-nee-uh) is the ...

  17. INNOVATIVE METHODS FOR EMISSION-INVENTORY DEVELOPMENT AND EVALUATION: WORKSHOP SUMMARY

    EPA Science Inventory

    Emission inventories are an essential tool for evaluating, managing, and regulating air pollution. Refinements and innovations in instruments that measure air pollutants, models that calculate emissions as well as techniques for data management and uncertainty assessment are nee...

  18. 77 FR 41205 - Sunshine Act Meetings; National Science Board

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-12

    ... Earthquake Engineering Research Infrastructure (NEES) Beyond 2014 ] Director's Remarks NSB Discussion Item... visitors must report to the NSF visitor desk located in the lobby at the 9th and N. Stuart Streets...

  19. Pernicious Anemia

    MedlinePlus

    ... from the NHLBI on Twitter. What Is Pernicious Anemia? Pernicious anemia (per-NISH-us uh-NEE-me-uh) is ... nervous system working properly. People who have pernicious anemia can't absorb enough vitamin B12 from food. ...

  20. What Are Some of the Basics of Infant Health?

    MedlinePlus

    ... movements usually consist of a thick, black or dark green substance called meconium (pronounced mi-KOH-nee- ... In a healthy child, urine is light to dark yellow in color. (The darker the color, the ...

  1. Relationship Between Ecosystem Productivity and Photosynthetically Active Radiation for Northern Peatlands

    NASA Technical Reports Server (NTRS)

    Frolking, S. E.; Bubier, J. L.; Moore, T. R.; Ball, T.; Bellisario, L. M.; Bhardwaj, A.; Carroll, P.; Crill, P. M.; Lafleur, P. M.; McCaughey, J. H.; hide

    1998-01-01

    We analyzed the relationship between net ecosystem exchange of carbon dioxide (NEE) and irradiance (as photosynthetic photon flux density or PPFD), using published and unpublished data that have been collected during midgrowing season for carbon balance studies at seven peatlands in North America and Europe, NEE measurements included both eddy-correlation tower and clear, static chamber methods, which gave very similar results. Data were analyzed by site, as aggregated data sets by peatland type (bog, poor fen, rich fen, and all fens) and as a single aggregated data set for all peatlands. In all cases, a fit with a rectangular hyperbola (NEE = alpha PPFD P(sub max)/(alpha PPFD + P(sub max) + R) better described the NEE-PPFD relationship than did a linear fit (NEE = beta PPFD + R). Poor and rich fens generally had similar NEE-PPFD relationships, while bogs had lower respiration rates (R = -2.0 micro mol m(exp -2) s(exp -1) for bogs and -2.7 micro mol m(exp -2) s(exp -1)) for fens) and lower NEE at moderate and high light levels (P(sub max)= 5.2 micro mol m(exp -2) s(exp -1) for bogs and 10.8 micro mol m(exp -2) s(exp -1) for fens). As a single class, northern peatlands had much smaller ecosystem respiration (R = -2.4 micro mol m(exp -2) s(exp -1)) and NEE rates (alpha = 0.020 and P(sub max)= 9.2 micro mol m(exp -2) s(exp -1)) than the upland ecosystems (closed canopy forest, grassland, and cropland). Despite this low productivity, northern peatland soil carbon pools are generally 5-50 times larger than upland ecosystems because of slow rates of decomposition caused by litter quality and anaerobic, cold soils.

  2. Evaluation of GEOSAT Data and Application to Variability of the Northeast Pacific Ocean

    DTIC Science & Technology

    1988-10-01

    while Diamante and Nee (1981) determined tidal constituents from GEOS-3 derived sea surfaces. Cheney and Marsh I (1981b) mapped mesoscale variability...Miller, L.L., and Porter , D.L. 1987. Geosat altimeter geophysical data record (GDR) user handbook. Rockville, MD: I NOAA National Ocean Service...University Applied Physics Laboratory Report 7292-9510. First revision. i I I 159 I Diamante , J.M., and Nee, T.S. 1981. Application of satellite

  3. Evaluation of GEOSAT (Geodetic Satellite) Data and Application to Variability of the Northeast Pacific Ocean

    DTIC Science & Technology

    1988-09-01

    locales using GEOS-3 outputs, while Diamante and Nee (1981) determined tidal constituents from GEOS-3 derived sea surfaces. Cheney and Marsh (1981b...and Porter , D.L. 1987. Geosat altimeter geophysical data record (GDR) user handbook. Rockville, MD: NOAA National Ocean Service. Cheney, R.E., and Marsh...Physics Laboratory Report 7292-9510. First revision. 15 Diamante , J.M., and Nee, T.S. 1981. Application of satellite radar altimeter data to the

  4. Relationship Between Ecosystem Productivity and Photosynthetically Active Radiation for Northern Peatlands

    NASA Technical Reports Server (NTRS)

    Frolking, S. E.; Bubier, J. L.; Moore, T. R.; Ball, T.; Bellisario, L. M.; Bhardwaj, A.; Carroll, P.; Crill, P. M.; Lafleur, P. M.; McCaughey, J. H.; Roulet, N. T.; Suyker, A. E.; Verma, S. B.; Waddington, J. M.; Whiting, G. J.

    1998-01-01

    We analyzed the relationship between net ecosystem exchange of carbon dioxide (NEE) and irradiance (as photosynthetic photon flux density or PPFD), using published and unpublished data that have been collected during midgrowing season for carbon balance studies at seven peatlands in North America and Europe, NEE measurements included both eddy-correlation tower and clear, static chamber methods, which gave very similar results. Data were analyzed by site, as aggregated data sets by peatland type (bog, poor fen, rich fen, and all fens) and as a single aggregated data set for all peatlands. In all cases, a fit with a rectangular hyperbola (NEE = alpha PPFD P(sub max)/(alpha PPFD + P(sub max) + R) better described the NEE-PPFD relationship than did a linear fit (NEE = beta PPFD + R). Poor and rich fens generally had similar NEE-PPFD relationships, while bogs had lower respiration rates (R = -2.0 micro mol m(exp -2) s(exp -1) for bogs and -2.7 micro mol m(exp -2) s(exp -1)) for fens) and lower NEE at moderate and high light levels (P(sub max)= 5.2 micro mol m(exp -2) s(exp -1) for bogs and 10.8 micro mol m(exp -2) s(exp -1) for fens). As a single class, northern peatlands had much smaller ecosystem respiration (R = -2.4 micro mol m(exp -2) s(exp -1)) and NEE rates (alpha = 0.020 and P(sub max)= 9.2 micro mol m(exp -2) s(exp -1)) than the upland ecosystems (closed canopy forest, grassland, and cropland). Despite this low productivity, northern peatland soil carbon pools are generally 5-50 times larger than upland ecosystems because of slow rates of decomposition caused by litter quality and anaerobic, cold soils.

  5. Standing litter as a driver of interannual CO2 exchange variability in a freshwater marsh

    NASA Astrophysics Data System (ADS)

    Rocha, A. V.; Potts, D. L.; Goulden, M. L.

    2008-12-01

    The San Joaquin Freshwater Marsh (SJFM) is a seasonally flooded Typha wetland in Southern California that is characterized by high rates of Aboveground Net Primary Production (ANPP) and a large accumulation of standing leaf litter. The ANPP, Gross and Net Ecosystem CO2 Exchange (GEE and NEE), and Enhanced Vegetation Index (EVI) at the SJFM fluctuate by ˜40% from year to year, in ways that are not directly attributable to variation in weather or the maximum green Leaf Area Index (LAImax). We tested the hypothesis that this variation is caused by a negative feedback between ANPP, the buildup of leaf litter, shading of green leaves by litter, a reduction in GEE and NEE, and a subsequent reduction in ANPP. Litter manipulations on replicated plots demonstrated that the presence of standing litter decreased plot-level NEE by 17 to 47% and surface EVI by 25 to 48%, even as green Leaf Area Index (LAIgreen) was held constant. Plot level NEE and surface EVI remained tightly correlated, and largely decoupled from LAIgreen, as standing litter was varied. This pattern paralleled that observed for the entire marsh, where NEE and EVI remained tightly correlated, and largely decoupled from LAImax, from year to year. Correcting LAIgreen and LAImax for the amount of shading caused by standing litter improved the correlations between LAI and EVI and NEE, indicating that EVI and NEE are most sensitive to the amount of unshaded LAI. The accumulation of standing litter at the SJFM decouples the relationships between LAI and EVI and NEE, and appears to be important for controlling the interannual variability observed at the site.

  6. Four new species of Tanycarpa (Hymenoptera, Braconidae, Alysiinae) from the Palaearctic Region and new records of species from China.

    PubMed

    Yao, Junli; Kula, Robert R; Wharton, Robert A; Chen, Jiahua

    2015-05-14

    Four new species of Tanycarpa (Hymenoptera, Braconidae, Alysiinae), T. gymnonotum Yao sp. n., T. similis Yao sp. n., T. areolata Yao sp. n., and T. lineata Yao sp. n., are described from the Palaearctic Region of China, and T. chors Belokobylskij is newly recorded from China. Significant range extensions are given for T. bicolor (Nees von Esenbeck), T. gracilicornis (Nees von Esenbeck), and T. mitis Stelfox. A key to the Palaearctic species of Tanycarpa is provided.

  7. Diagnostic outcomes of inpatient video electroencephalography: nonepileptic events in South Carolina.

    PubMed

    Koontz, Elizabeth H; Hanson, Jarom; Pritchard, Paul B

    2013-09-01

    The Epilepsy Monitoring Unit (EMU) was established at the Medical University Hospital to assist in the diagnosis of epilepsy and the evaluation of other paroxysmal neurological symptoms, including non-epileptic events (NEEs), which are often confused with epileptic seizures. Correct diagnosis can prevent inappropriate treatment with antiepileptic drugs, avoid some of the restrictions imposed by epileptic seizures, and facilitate appropriate treatment for NEEs. A retrospective review of patients admitted to the EMU over a two year period showed the percentage of patients diagnosed with NEEs (39%) is greater than those diagnosed with epilepsy alone (36%). This incidence of NEE is higher than in other academic medical centers. The explanations for this disparity are not fully defined, but warrant further study as to patient demographics, risk factors, and referral patterns in South Carolina. The average time from when patients began having events to accurate diagnosis of NEEs was 4.5 years, and 21 patients had NEEs for at least 10 years prior to diagnosis.

  8. Evaluating terrestrial CO2 flux diagnoses and uncertainties from a simple land surface model and its residuals

    NASA Astrophysics Data System (ADS)

    Hilton, T. W.; Davis, K. J.; Keller, K.

    2014-01-01

    Global terrestrial atmosphere-ecosystem carbon dioxide fluxes are well constrained by the concentration and isotopic composition of atmospheric carbon dioxide. In contrast, considerable uncertainty persists surrounding regional contributions to the net global flux as well as the impacts of atmospheric and biological processes that drive the net flux. These uncertainties severely limit our ability to make confident predictions of future terrestrial biological carbon fluxes. Here we use a simple light-use efficiency land surface model (the Vegetation Photosynthesis Respiration Model, VPRM) driven by remotely sensed temperature, moisture, and phenology to diagnose North American gross ecosystem exchange (GEE), ecosystem respiration, and net ecosystem exchange (NEE) for the period 2001 to 2006. We optimize VPRM parameters to eddy covariance (EC) NEE observations from 65 North American FluxNet sites. We use a separate set of 27 cross-validation FluxNet sites to evaluate a range of spatial and temporal resolutions for parameter estimation. With these results we demonstrate that different spatial and temporal groupings of EC sites for parameter estimation achieve similar sum of squared residuals values through radically different spatial patterns of NEE. We also derive a regression model to estimate observed VPRM errors as a function of VPRM NEE, temperature, and precipitation. Because this estimate is based on model-observation residuals it is comprehensive of all the error sources present in modeled fluxes. We find that 1 km interannual variability in VPRM NEE is of similar magnitude to estimated 1 km VPRM NEE errors.

  9. Authentication of true cinnamon (Cinnamon verum) utilising direct analysis in real time (DART)-QToF-MS.

    PubMed

    Avula, Bharathi; Smillie, Troy J; Wang, Yan-Hong; Zweigenbaum, Jerry; Khan, Ikhlas A

    2015-01-01

    The use of cinnamon as a spice and flavouring agent is widespread throughout the world. Many different species of plants are commonly referred to as 'cinnamon'. 'True cinnamon' refers to the dried inner bark of Cinnamomum verum J. S. Presl (syn. C. zeylanicum) (Lauraceae). Other 'cinnamon' species, C. cassia (Nees & T. Nees) J. Presl (syn. C. aromaticum Nees) (Chinese cassia), C. loureiroi Nees (Saigon cassia), and C. burmannii (Nees & T. Nees) Blume (Indonesian cassia), commonly known as cassia, are also marketed as cinnamon. Since there is a prevalence of these various types of 'cinnamons' on the market, there is a need to develop a rapid technique that can readily differentiate between true cinnamon (C. verum) and other commonly marketed species. In the present study, coumarin and other marker compounds indicative of 'cinnamon' were analysed using DART-QToF-MS in various samples of cinnamon. This method involved the use of [M + H](+) ions in positive mode in addition to principal component analysis (PCA) using Mass Profiler Professional software to visualise several samples for quality and to discriminate 'true cinnamon' from other Cinnamomum species using the accurate mass capabilities of QToF-MS.

  10. Direct and indirect effects of elevated atmospheric CO2 on net ecosystem production in a Chesapeake Bay tidal wetland.

    PubMed

    Erickson, John E; Peresta, Gary; Montovan, Kathryn J; Drake, Bert G

    2013-11-01

    The rapid increase in atmospheric CO2 concentrations (Ca ) has resulted in extensive research efforts to understand its impact on terrestrial ecosystems, especially carbon balance. Despite these efforts, there are relatively few data comparing net ecosystem exchange of CO2 between the atmosphere and the biosphere (NEE), under both ambient and elevated Ca . Here we report data on annual sums of CO2 (NEE(net) ) for 19 years on a Chesapeake Bay tidal wetland for Scirpus olneyi (C3 photosynthetic pathway)- and Spartina patens (C4 photosynthetic pathway)-dominated high marsh communities exposed to ambient and elevated Ca (ambient + 340 ppm). Our objectives were to (i) quantify effects of elevated Ca on seasonally integrated CO2 assimilation (NEE(net) = NEE(day) + NEE(night) , kg C m(-2) y(-1) ) for the two communities; and (ii) quantify effects of altered canopy N content on ecosystem photosynthesis and respiration. Across all years, NEE(net) averaged 1.9 kg m(-2) y(-1) in ambient Ca and 2.5 kg m(-2) y(-1) in elevated Ca , for the C3 -dominated community. Similarly, elevated Ca significantly (P < 0.01) increased carbon uptake in the C4 -dominated community, as NEE(net) averaged 1.5 kg m(-2) y(-1) in ambient Ca and 1.7 kg m(-2) y(-1) in elevated Ca . This resulted in an average CO2 stimulation of 32% and 13% of seasonally integrated NEE(net) for the C3 - and C4 -dominated communities, respectively. Increased NEE(day) was correlated with increased efficiencies of light and nitrogen use for net carbon assimilation under elevated Ca , while decreased NEE(night) was associated with lower canopy nitrogen content. These results suggest that rising Ca may increase carbon assimilation in both C3 - and C4 -dominated wetland communities. The challenge remains to identify the fate of the assimilated carbon. Published 2013. This article is a U.S. Government work and is in the public domain in the U.S.A.

  11. Effects of biased CO2 flux measurements by open-path sensors on the interpretation of CO2 flux dynamics at contrasting ecosystems

    NASA Astrophysics Data System (ADS)

    Helbig, Manuel; Humphreys, Elyn; Bogoev, Ivan; Quinton, William L.; Wischnweski, Karoline; Sonnentag, Oliver

    2015-04-01

    Long-term measurements of net ecosystem exchange of CO2 (NEE) are conducted across a global network of flux tower sites. These sites are characterised by varying climatic and vegetation conditions, but also differ in the type of CO2/H2O gas analyser used to obtain NEE. Several studies have observed a systematic bias in measured NEE when comparing open-path (OP) and closed-path (CP) sensors with consistently more negative daytime NEE measurements when using OP sensors, both during the growing and non-growing season. A surface heating correction has been proposed in the literature, but seems not to be universally applicable. Systematic biases in NEE measurements are particularly problematic for synthesis papers and inter-comparison studies between sites where the 'true' NEE is small compared to the potential instrument bias. For example, NEE estimates for boreal forest sites derived from OP sensors show large, ecologically unreasonable winter CO2 uptake. To better understand the causes and the magnitude of this potential bias, we conducted a sensor inter-comparison study at the Mer Bleue peatland near Ottawa, ON, Canada. An eddy covariance system with a CP (LI7000 & GILL R3-50) and an OP sensor (EC150 & CSAT3A) was used. Measurements were made between September 2012 and January 2013 and covered late summer, fall, and winter conditions. Flux calculations were made as consistently as possible to minimise differences due to differing processing procedures (e.g. spectral corrections). The latent (LE, slope of orthogonal linear regression of LEOP on LECP: 1.02 ± 0.01 & intercept: -0.2 ± 0.6 W m-2 and sensible heat fluxes (H, slope of HCSAT3A on HGILL: 0.96 ± 0.01 & intercept: 0.1 ± 0.03 W m-2) did not show any significant bias. However, a significant bias was apparent in the NEE measurements (slope of NEEOP on NEECP: 1.36 ± 0.02 & intercept: -0.1 ± 0.05). The differences between NEEOP and NEECP were linearly related to the magnitude of HCSAT3A with a slope of -0

  12. Benchmarking the seasonal cycle of CO2 fluxes simulated by terrestrial ecosystem models

    NASA Astrophysics Data System (ADS)

    Peng, Shushi; Ciais, Philippe; Chevallier, Frédéric; Peylin, Philippe; Cadule, Patricia; Sitch, Stephen; Piao, Shilong; Ahlström, Anders; Huntingford, Chris; Levy, Peter; Li, Xiran; Liu, Yongwen; Lomas, Mark; Poulter, Benjamin; Viovy, Nicolas; Wang, Tao; Wang, Xuhui; Zaehle, Sönke; Zeng, Ning; Zhao, Fang; Zhao, Hongfang

    2015-01-01

    We evaluated the seasonality of CO2 fluxes simulated by nine terrestrial ecosystem models of the TRENDY project against (1) the seasonal cycle of gross primary production (GPP) and net ecosystem exchange (NEE) measured at flux tower sites over different biomes, (2) gridded monthly Model Tree Ensembles-estimated GPP (MTE-GPP) and MTE-NEE obtained by interpolating many flux tower measurements with a machine-learning algorithm, (3) atmospheric CO2 mole fraction measurements at surface sites, and (4) CO2 total columns (XCO2) measurements from the Total Carbon Column Observing Network (TCCON). For comparison with atmospheric CO2 measurements, the LMDZ4 transport model was run with time-varying CO2 fluxes of each model as surface boundary conditions. Seven out of the nine models overestimate the seasonal amplitude of GPP and produce a too early start in spring at most flux sites. Despite their positive bias for GPP, the nine models underestimate NEE at most flux sites and in the Northern Hemisphere compared with MTE-NEE. Comparison with surface atmospheric CO2 measurements confirms that most models underestimate the seasonal amplitude of NEE in the Northern Hemisphere (except CLM4C and SDGVM). Comparison with TCCON data also shows that the seasonal amplitude of XCO2 is underestimated by more than 10% for seven out of the nine models (except for CLM4C and SDGVM) and that the MTE-NEE product is closer to the TCCON data using LMDZ4. From CO2 columns measured routinely at 10 TCCON sites, the constrained amplitude of NEE over the Northern Hemisphere is of 1.6 ± 0.4 gC m-2 d-1, which translates into a net CO2 uptake during the carbon uptake period in the Northern Hemisphere of 7.9 ± 2.0 PgC yr-1.

  13. Drivers of long-term variability in CO2 net ecosystem exchange in a temperate peatland

    NASA Astrophysics Data System (ADS)

    Helfter, C.; Campbell, C.; Dinsmore, K. J.; Drewer, J.; Coyle, M.; Anderson, M.; Skiba, U.; Nemitz, E.; Billett, M. F.; Sutton, M. A.

    2015-03-01

    Land-atmosphere exchange of carbon dioxide (CO2) in peatlands exhibits marked seasonal and inter-annual variability, which subsequently affects the carbon (C) sink strength of catchments across multiple temporal scales. Long-term studies are needed to fully capture the natural variability and therefore identify the key hydrometeorological drivers in the net ecosystem exchange (NEE) of CO2. Since 2002, NEE has been measured continuously by eddy-covariance at Auchencorth Moss, a temperate lowland peatland in central Scotland. Hence this is one of the longest peatland NEE studies to date. For 11 years, the site was a consistent, yet variable, atmospheric CO2 sink ranging from -5.2 to -135.9 g CO2-C m-2 yr-1 (mean of -64.1 ± 33.6 g CO2-C m-2 yr-1). Inter-annual variability in NEE was positively correlated to the length of the growing season. Mean winter air temperature explained 87% of the inter-annual variability in the sink strength of the following summer, indicating an effect of winter climate on local phenology. Ecosystem respiration (Reco) was enhanced by drought, which also depressed gross primary productivity (GPP). The CO2 uptake rate during the growing season was comparable to three other sites with long-term NEE records; however, the emission rate during the dormant season was significantly higher. To summarise, the NEE of the peatland studied is modulated by two dominant factors: - phenology of the plant community, which is driven by winter air temperature and impacts photosynthetic potential and net CO2 uptake during the growing season (colder winters are linked to lower summer NEE), - water table level, which enhanced soil respiration and decreased GPP during dry spells. Although summer dry spells were sporadic during the study period, the positive effects of the current climatic trend towards milder winters on the site's CO2 sink strength could be offset by changes in precipitation patterns especially during the growing season.

  14. Contemporary mire net ecosystem carbon balance - controls and susceptibility to change (Invited)

    NASA Astrophysics Data System (ADS)

    Nilsson, M. B.

    2013-12-01

    In this presentation I will address three main issues: 1 - The relative importance of the component carbon (C) fluxes for the annual mire Net Ecosystem Carbon Balance (NECB); 2 - The importance of gross primary production (GPP) versus ecosystem respiration (Reco) for the annual Net Ecosystem Exchange (NEE) and finally; 3) the degree of consistency or inconsistency in how controlling factors affects NEE of different mire types. The annual mire NECB is made up principally by the biosphere-atmosphere exchange of CO2 (NEE) and CH4 and the runoff C-export. One important research issue is to further understand what controls the relative contribution from the component fluxes to the annual mire NECB. A second important major research issue is to reveal the relative importance of gross photosynthesis (GPP) and ecosystem respiration (Reco) respectively for the annual mire NEE. The relative importance of GPP and Reco respectively for the NECB also encounters the effect of changes in the lengths of the growing season and non-growing season respectively. The general understanding is that the low rate of decomposition constitutes the major control on peat accumulation. There is though growing evidences from estimates of contemporary annual as well as growing season NEE and peat core based estimates of long-term C accumulation that GPP is at least as important for the annual NEE. Finally, I will address the question to what extent different mire types respond differently to controlling e.g. if bogs and fens respond differently. Recent empirical as well as modeling studies indicate that e.g. changes in water table level causes contrasting response in NEE between bogs and fens.

  15. A Conceptual model of Ecophysiological Function across the Amazon Basin using a Synthesis of Observed and Model Data.

    NASA Astrophysics Data System (ADS)

    Baker, I. T.; Denning, A. S.; Harper, A. B.

    2008-12-01

    Observations of the seasonal cycle of Net Ecosystem Exchange of Carbon (NEE) are variable across the Amazon Basin. NEE has been observed to be nearly uniform through the year at sites such as Cueiras Reserve in Amazonas. A pattern of efflux during the wet season and uptake during seasonal drought has been observed at multiple sites in the Tapajos River National Forest, while the opposite pattern (uptake during wet season, efflux during seasonal drought) has been observed at several sites in Mato Grosso . Using a synthesis of eddy covariance flux observations from multiple sites across vegetation and moisture gradients in the Amazon basin and a biophysical model (Simple Biosphere Model, SiB), we construct a conceptual model of the patterns of ecophysiological function that determine annual cycles and interannual variability in observed NEE across tropical Amazonia. We identify several factors that determine the behavior of Gross Primary Productivity (GPP) and respiration fluxes, while NEE is determined by their sum. We evaluate our conceptual model across a pseudo-latitudinal gradient from extremely wet (more than 2000 mm annual precipitation) in the north to drier cerrado (savanna) regions in the south. In the extremely wet regions near the equator we find little or no stress on photosynthesis and, subsequently, little or no variability in annual cycles of energy or carbon flux. In these regions NEE is determined by vegetation response to high-frequency meteorological events. As precipitation decreases, the flux seasonality increases and phase relationships between GPP and respiration determine annual NEE cycles. As GPP/respiration cycles transition from an out-of-phase relationship in wetter regions to an in-phase pattern in the cerrado, NEE changes from dry to wet season carbon uptake.

  16. Remote Estimation Of Net Ecosystem Carbon Dioxide Exchange In Crops: Principles, Algorithm Calibration And Validation

    NASA Astrophysics Data System (ADS)

    Gitelson, A. A.; Vina, A.; Verma, S. B.; Rundquist, D. C.; Keydan, G. P.; Leavitt, B.; Arkebauer, T. J.; Burba, G. G.; Suyker, A. E.

    2004-12-01

    Accurate estimation of spatially distributed CO2 fluxes is of great importance for regional and global carbon balance studies. Tower-based instruments provide flux data from a small footprint area and scaling beyond the footprint to the region is quite challenging. We developed a technique that relates tower-based mid-day CO2 exchange data with remotely sensed reflectances in the near infrared and either the green (around 550 nm) or the red-edge (near 700 nm) spectral ranges, to accurately estimate net ecosystem CO2 exchange (NEE) in commodity crops. The technique, which is solely based on remotely sensed data, was tested for mid-day NEE estimation in irrigated and rainfed maize and soybean during three seasons (2001 through 2003). The technique provides accurate estimations of mid-day NEE in crops, explaining more than 88% of NEE variation in maize and 86% in soybean, and shows great potential for remotely tracking crop NEE. The technique was validated by an independent data set; root mean square error in predicting mid-day NEE in the range 0-2.5 mgCm-2s-1 was 0.3 mgCm-2s-1 using NIR and red-edge bands and 0.38 mgCm-2s-1 using NIR and green bands. The developed technique will improve our understanding of how to retrieve crop ecosystem CO2 exchange synoptically. By improving the accuracy of retrievals, we will advance the understanding of regional and global carbon dynamics, reducing the uncertainties attendant to NEE estimation in crops.

  17. Effects of thinning on carbon dioxide exchanges in a mixed boreal forest

    NASA Astrophysics Data System (ADS)

    Lindroth, Anders; Heliasz, Michal; Holst, Jutta; Mölder, Meelis; Vestin, Patrik; Lagergren, Fredrik; Biermann, Tobias; Sundqvist, Elin

    2017-04-01

    We used eddy covariance measurements of net ecosystem exchange (NEE) above (2007-2016) to assess the effects of thinning on the fluxes in the Norunda forest in central Sweden. The thinning was performed in a half-circle sector from the mast extending 200 m outwards. The thinning operation that was made in winter 2008/2009 harvested about 25% of the volume in the ca. 110 years mixed pine and spruce stand. Thus, for above canopy fluxes we had two years before the thinning and eight years after the thinning. We focused the analyses on the main part of the growing season May-August during which most of the exchanges take place. One of the problems with a 'change' study like this is the large temporal variability in the fluxes caused by the variability in the drivers. We therefore created a normalized NEE besides the actual values in order to try to assess statistically if observed differences were 'real' or caused by differences in drivers. Daytime NEE was normalized by dividing each half-hour value with the corresponding value from an average light response curve. We also used simple models of daytime NEE (light response curve) and night time NEE during well mixed conditions (temperature driven respiration model) were the model parameters were fitted to the whole dataset thus representing 'average' responses to those drivers involved. The main result was that the actual NEE during the first years after the thinning was reduced by about 40% but because of the large inter-annual variability even after normalization, it could not be concluded statistically that these differences were caused by the thinning. However, there was a clear trend with increasing NEE (more negative) with time after thinning and decreasing respiration. Models did not show any trends so the conclusion was that the trends were caused by the thinning.

  18. Seasonal and inter-annual variability of the net ecosystem CO2 exchange of a temperate mountain grassland: effects of climate and management

    PubMed Central

    Wohlfahrt, Georg; Hammerle, Albin; Haslwanter, Alois; Bahn, Michael; Tappeiner, Ulrike; Cernusca, Alexander

    2013-01-01

    The role and relative importance of climate and cutting for the seasonal and inter-annual variability of the net ecosystem CO2 (NEE) of a temperate mountain grassland was investigated. Eddy covariance CO2 flux data and associated measurements of the green area index and the major environmental driving forces acquired during 2001-2006 at the study site Neustift (Austria) were analyzed. Driven by three cutting events per year which kept the investigated grassland in a stage of vigorous growth, the seasonal variability of NEE was primarily modulated by gross primary productivity (GPP). The role of environmental parameters in modulating the seasonal variability of NEE was obscured by the strong response of GPP to changes in the amount of green area, as well as the cutting-mediated decoupling of phenological development and the seasonal course of climate drivers. None of the climate and management metrics examined was able to explain the inter-annual variability of annual NEE. This is thought to result from (1) a high covariance between GPP and ecosystem respiration (Reco) at the annual time scale which results in a comparatively small inter-annual variation of NEE, (2) compensating effects between carbon exchange during and outside the management period, and (3) changes in the biotic response to rather than the climate variables per se. GPP was more important in modulating inter-annual variations in NEE in spring and before the first and second cut, while Reco explained a larger fraction of the inter-annual variability of NEE during the remaining, in particular the post-cut, periods. PMID:24383047

  19. Reproduction of Meloidogyne marylandi and M. incognita on several Poaceae

    PubMed Central

    Faske, T. R.

    2009-01-01

    The susceptibility of 22 plant species to Meloidogyne marylandi and M. incognita was examined in three greenhouse experiments. Inoculum of M. marylandi was eggs from cultures maintained on Zoysia matrella “Cavalier” or Cynodon dactylon x C. trasvaalensis “Tifdwarf”. Inoculum of M. incognita was eggs from cultures maintained on Solanum lycopersicum ‘Rutgers’. In each host test the inoculum density was 2,000 nematode eggs/pot. None of the three dicot species tested (Gossypium hirsutum, Arachis hypogaea, and S. lycopersicum) were hosts for M. marylandi but, as expected, M. incognita had high levels of reproduction on G. hirsutum and S. lycopersicum. Meloidogyne marylandi reproduced on all of the 19 grass species (Poaceae) tested but reproduction varied greatly (P = 0.05) among these hosts. The following grasses were identified for the first time as hosts for M. marylandi: Buchloe dactyloides (buffalograss), Echinochloa colona (jungle rice), Eragostis curvula (weeping lovegrass), Paspalum dilatatum (dallisgrass), P. notatum (bahiagrass), Sorghastrum, nutans (indiangrass), Tripsacum dactyloides (eastern gamagrass), and Zoysia matrella (zoysiagrass). No reproduction of M. incognita was observed on B. dactyloides, Cyndon dactylon (common bermudagrass), E. curvula, P. vaginatum (seashore paspalum), S. nutans, T. dactyloides, Z. matrella or Z. japonica. Reproduction of M. incognita was less than reproduction of M. marylandi on the other grass species, except for the Zea mays inbred line B73 on which M. incognita had greater reproduction than did M. marylandi (P = 0.05) and Stenotaphrum secundatum (St. Augustinegrass) on which M. incognita and M. marylandi had similar levels of reproduction. PMID:22661770

  20. Comparison between eddy covariance and automatic chamber techniques for measuring net ecosystem exchange of carbon dioxide in cotton and wheat fields

    NASA Astrophysics Data System (ADS)

    Wang, K.; Liu, C.; Zheng, X.; Pihlatie, M.; Li, B.; Haapanala, S.; Vesala, T.; Liu, H.; Wang, Y.; Liu, G.; Hu, F.

    2013-05-01

    Static and transparent automatic chamber (AC) technique is a~necessary choice for measuring net ecosystem exchange (NEE) of carbon dioxide (CO2) in circumstances where eddy covariance (EC) technique is not applicable. However, a comparison of the two techniques for measurements on croplands has seldom been undertaken. We carried out NEE observations in a cotton field (for one year) and a winter wheat field (for one cropping season) using both AC and EC techniques, to (a) compare the NEE fluxes measured using each technique, and (b) test the NEE measurement performance of an automatic chamber system (AMEG), which was designed for simultaneous flux measurements of multiple gases. The half-hourly NEE fluxes measured with the two techniques were in approximate agreement, with the AC fluxes being 0.78 (cotton) and 1.06 (wheat) times those of the EC. When integrated to daily timescale, the fluxes of the two techniques were in better agreement, showing an average ratio of 0.94 and 1.00 for the cotton and wheat, respectively. During the periods with comparable field conditions and normal performance of both instruments, the cumulative NEE fluxes revealed small differences between the two techniques (-9.0 ~ 6.7%, with a mean of 0.1%). The measurements resulted in annual cumulative NEE of -40 g C m-2 yr-1 (EC) and -42 g C m-2 yr-1 (AC) in the cotton field and seasonal cumulative NEE of -251 g C m-2 (EC) and -205 g C m-2 (AC) in the wheat field. Our results indicate that, for cropland populated by short plants, the AMEG system and the data processing procedures applied in this study are able to provide NEE estimates comparable to those from EC measurements, although either technique may lead to an overestimation of the loss rate (or underestimation of the gain rate) of the soil organic carbon stock of an ecosystem, in particular with calcareous soils exposed to increasing atmospheric acid deposition.

  1. Evaluating the agreement between measurements and models of net ecosystem exchange at different times and time scales using wavelet coherence: an example using data from the North American Carbon Program Site-Level Interim Synthesis

    NASA Astrophysics Data System (ADS)

    Stoy, P. C.; Dietze, M.; Richardson, A. D.; Vargas, R.; Barr, A. G.; Anderson, R. S.; Arain, M. A.; Baker, I. T.; Black, T. A.; Chen, J. M.; Cook, R. B.; Gough, C. M.; Grant, R. F.; Hollinger, D. Y.; Izaurralde, R. C.; Kucharik, C. J.; Lafleur, P.; Law, B. E.; Liu, S.; Lokupitiya, E.; Luo, Y.; Munger, J. W.; Peng, C.; Poulter, B.; Price, D. T.; Ricciuto, D. M.; Riley, W. J.; Sahoo, A. K.; Schaefer, K.; Schwalm, C. R.; Tian, H.; Verbeeck, H.; Weng, E.

    2013-02-01

    Earth system processes exhibit complex patterns across time, as do the models that seek to replicate these processes. Model output may or may not be significantly related to observations at different times and on different frequencies. Conventional model diagnostics provide an aggregate view of model-data agreement, but usually do not identify the time and frequency patterns of model misfit, leaving unclear the steps required to improve model response to environmental drivers that vary on characteristic frequencies. Wavelet coherence can quantify the times and frequencies at which models and measurements are significantly different. We applied wavelet coherence to interpret the predictions of twenty ecosystem models from the North American Carbon Program (NACP) Site-Level Interim Synthesis when confronted with eddy covariance-measured net ecosystem exchange (NEE) from ten ecosystems with multiple years of available data. Models were grouped into classes with similar approaches for incorporating phenology, the calculation of NEE, and the inclusion of foliar nitrogen (N). Models with prescribed, rather than prognostic, phenology often fit NEE observations better on annual to interannual time scales in grassland, wetland and agricultural ecosystems. Models that calculate NEE as net primary productivity (NPP) minus heterotrophic respiration (HR) rather than gross ecosystem productivity (GPP) minus ecosystem respiration (ER) fit better on annual time scales in grassland and wetland ecosystems, but models that calculate NEE as GPP - ER were superior on monthly to seasonal time scales in two coniferous forests. Models that incorporated foliar nitrogen (N) data were successful at capturing NEE variability on interannual (multiple year) time scales at Howland Forest, Maine. Combined with previous findings, our results suggest that the mechanisms driving daily and annual NEE variability tend to be correctly simulated, but the magnitude of these fluxes is often erroneous

  2. Evaluating the agreement between measurements and models of net ecosystem exchange at different times and timescales using wavelet coherence: an example using data from the North American Carbon Program Site-Level Interim Synthesis

    NASA Astrophysics Data System (ADS)

    Stoy, P. C.; Dietze, M. C.; Richardson, A. D.; Vargas, R.; Barr, A. G.; Anderson, R. S.; Arain, M. A.; Baker, I. T.; Black, T. A.; Chen, J. M.; Cook, R. B.; Gough, C. M.; Grant, R. F.; Hollinger, D. Y.; Izaurralde, R. C.; Kucharik, C. J.; Lafleur, P.; Law, B. E.; Liu, S.; Lokupitiya, E.; Luo, Y.; Munger, J. W.; Peng, C.; Poulter, B.; Price, D. T.; Ricciuto, D. M.; Riley, W. J.; Sahoo, A. K.; Schaefer, K.; Schwalm, C. R.; Tian, H.; Verbeeck, H.; Weng, E.

    2013-11-01

    Earth system processes exhibit complex patterns across time, as do the models that seek to replicate these processes. Model output may or may not be significantly related to observations at different times and on different frequencies. Conventional model diagnostics provide an aggregate view of model-data agreement, but usually do not identify the time and frequency patterns of model-data disagreement, leaving unclear the steps required to improve model response to environmental drivers that vary on characteristic frequencies. Wavelet coherence can quantify the times and timescales at which two time series, for example time series of models and measurements, are significantly different. We applied wavelet coherence to interpret the predictions of 20 ecosystem models from the North American Carbon Program (NACP) Site-Level Interim Synthesis when confronted with eddy-covariance-measured net ecosystem exchange (NEE) from 10 ecosystems with multiple years of available data. Models were grouped into classes with similar approaches for incorporating phenology, the calculation of NEE, the inclusion of foliar nitrogen (N), and the use of model-data fusion. Models with prescribed, rather than prognostic, phenology often fit NEE observations better on annual to interannual timescales in grassland, wetland and agricultural ecosystems. Models that calculated NEE as net primary productivity (NPP) minus heterotrophic respiration (HR) rather than gross ecosystem productivity (GPP) minus ecosystem respiration (ER) fit better on annual timescales in grassland and wetland ecosystems, but models that calculated NEE as GPP minus ER were superior on monthly to seasonal timescales in two coniferous forests. Models that incorporated foliar nitrogen (N) data were successful at capturing NEE variability on interannual (multiple year) timescales at Howland Forest, Maine. The model that employed a model-data fusion approach often, but not always, resulted in improved fit to data, suggesting

  3. Variations in net CO2 flux across a tropical savanna landscape due to spatial variations in hydrology and land use

    NASA Astrophysics Data System (ADS)

    Arruda, P. H. Z. D.; Vourlitis, G. L.; Santanna, F. B.; Lobo, F. D. A., Sr.; Nogueira, J. D. S.; Pinto-Jr, O. B.

    2016-12-01

    The savanna vegetation of Brazil (Cerrado) accounts for 20-25% of the land cover of Brazil; however, large spatial variations in vegetation type, hydrology, and land use presumably result in large spatial and temporal variations in ecosystem mass and energy exchange. We used eddy covariance to measure the net ecosystem CO2 exchange (NEE) of grass-dominated Cerrado (campo sujo) over three years and partitioned the flux footprint into three sectors that varied with respect to seasonal hydrology (flooded vs. upland) and land use (mowed vs. unmowed). We hypothesized that spatial variations in hydrology and land use would cause spatial variations in the direction and magnitude of net ecosystem CO2 exchange (NEE). Average daily NEE during the wet season for the flooded and unmowed upland sectors ranged between -0.75- -3.25 umol m-2 s-1, while NEE fluxes for the mowed sector ranged between -0.60- +1.50 umol m-2 s-1 (negative values indicate net ecosystem CO2 uptake). Thus, over the 3 year study period the mowed sector was a not source of CO2 to the atmosphere while the flooded and upland sectors were net CO2 sinks during the wet season. In contrast, both upland and flooded sectors were net sources of CO2 to the atmosphere during the dry season while the mowed sector was approximately in balance. Mowing savanna grasses during the dry season caused net daytime NEE (a proxy for net photosynthesis) to increase significantly compared to the flooded and upland surfaces; however, mowed areas had lower daytime NEE during the wet season compared to the other sectors. Nighttime rates of NEE (a proxy for ecosystem respiration) were similar for all sectors regardless of season and land use. Thus, differences in NEE due to seasonal variations in hydrology and land use acted to alter photosynthetic C gain rather than respiration. Our results indicate that the NEE of grass-dominated Cerrado is very sensitive to land management practices that alter leaf area index and photosynthetic C

  4. Long term effects of fen restoration: Parameterization of net ecosystem exchange models along a land use-degradation gradient

    NASA Astrophysics Data System (ADS)

    Bergmann, L.; Drösler, M.; Schultz, R.; Freibauer, A.; Jungkunst, H.; Höll, B.

    2010-05-01

    In combination with fluctuating water regimes and extreme variations in weather conditions expected through climate change, continual disturbance to the soils through peat use poses a risk to the carbon storage capacities and sequestration potentials of peatlands. Restoration and/ or extensive use of peatlands are strategies to optimize vegetation and hydrological balance within these sensitive ecosystems. Our goal was to determine the long term effects of fen restoration on CO2 fluxes and to identify the driving parameters causing differential fluxes along a disturbance gradient. This study aimed specifically to provide a CO2-C flux dataset to determine net ecosystem exchange (NEE) in restored temperate fens ecosystems. A climate controlled chamber system was used for measuring instantaneous NEE over the entire year in the Donauried in 2005 and in the Loisach-Kochelsee fens in 2006, both in southern Germany. The sites were chosen to represent both a management gradient (from intensive grasslands and crops to long-term restored Carex lawns) and a water table gradient (-78 cm below surface to -1 cm below surface). NEE was measured using the closed chamber technique, allowing for separation of NEE into gross ecosystem production (GEP) and ecosystem respiration (Reco). In both study areas, management strongly influenced ecosystem respiration and GPP and thus NEE, where Reco remained a strong determinant of NEE balances. Whereas the managed-degraded sites are acting as sources of CO2, a positive effect of restoration is seen in terms of NEE exchange. The restored sites are either acting as significant sinks for CO2 (Donauried old restored sites) or are have significantly lower emissions as the managed-degraded sites. NEE values ranged from 1041 g CO2-C m2 a1source to the atmosphere in a two cut grassland to a -130 g CO2-C m2 a1sinkin the long-term restored unmanaged Carex paniculata site. Reco was highest in grassland sites and lowest in the restored Carex sites. A

  5. Theory and experiments for voltammetric and SECM investigations and application to ORR electrocatalysis at nanoelectrode ensembles of ultramicroelectrode dimensions.

    PubMed

    Fernández, José L; Wijesinghe, Manjula; Zoski, Cynthia G

    2015-01-20

    Theoretical and experimental approaches to characterizing nanoelectrode (NE) ensembles of ultramicroelectrode dimensions (UME-NEEs) as a function of fraction of active area and random NE distribution are described. UME-NEEs were fabricated by addressing microregions of a gold-filled polycarbonate membrane through the UMEs of an underlying microfabricated addressable array. Results of Comsol Multiphysics 3D simulations based on randomly spaced NEs of 15 nm radius on a UME disk geometry of radii up to 5 μm are shown for steady-state voltammetry (SSV) and scanning electrochemical microscopy (SECM) experiments. Analytical equations were developed to describe the diffusion-limited steady-state current and steady-state voltammogram at an UME-NEE. These equations are shown to be in good agreement with the simulations and enabled evaluation of experimental SSVs. Comparison of experimental and simulated SECM approach curves, images, and tip voltammograms enabled the fraction of active area and distribution of NEs to be visualized and determined for individual UME-NEEs. Gold UME-NEEs are shown to be unique platforms for electrodeposition in forming nanoparticle electrodes (UME-NPEs). Electrocatalysis results for the oxygen reduction reaction (ORR) on Pt UME-NPEs in 0.1 M H2SO4 are also shown.

  6. Electrodiagnostic examination of lumbosacral radiculopathies.

    PubMed

    Weber, F; Albert, U

    2000-06-01

    To determine the diagnostic efficacy of late responses and of magnetic stimulation in the electrodiagnostic evaluation of lumbosacral radiculopathies, 42 patients with acute monoradiculopathies of L5 or S1 were examined. We performed conventional nerve conduction studies, F-wave studies, needle electrode examination (NEE) and magnetic stimulation. The results were compared with a control group of 36 persons. In the patients with weakness, we found a diagnostic sensitivity for NEE of 90% in L5 and of 80% in S1. F-waves had the same sensitivity as NEE in the patients with weakness and were more sensitive in the group of patients without weakness (L5 80%, S1 67%). Magnetic stimulation had a sensitivity of 40% in all groups. There were also abnormalities of NEE and of F-wave studies in the patients with abnormal magnetic stimulation. It is concluded that NEE is the single most effective method in acute LSR and that F-wave studies are able to provide complementary information. Magnetically evoked motor nerve root stimulation was not found of clinically relevant diagnostic value.

  7. Carbon exchange between the atmosphere and subtropical forested cypress and pine wetlands

    USGS Publications Warehouse

    Shoemaker, W. Barclay; Anderson, Frank E.; Barr, Jordan G.; Graham, Scott L.; Botkin, Daniel B.

    2015-01-01

    Carbon dioxide exchange between the atmosphere and forested subtropical wetlands is largely unknown. Here we report a first step in characterizing this atmospheric–ecosystem carbon (C) exchange, for cypress strands and pine forests in the Greater Everglades of Florida as measured with eddy covariance methods at three locations (Cypress Swamp, Dwarf Cypress and Pine Upland) for 2 years. Links between water and C cycles are also examined at these three sites, as are methane emission measured only at the Dwarf Cypress site. Each forested wetland showed net C uptake from the atmosphere both monthly and annually, as indicated by the net ecosystem exchange (NEE) of carbon dioxide (CO2). For this study, NEE is the difference between photosynthesis and respiration, with negative values representing uptake from the atmosphere that is retained in the ecosystem or transported laterally via overland flow (unmeasured for this study). Atmospheric C uptake (NEE) was greatest at the Cypress Swampp (−900 to −1000 g C m2 yr−1), moderate at the Pine Upland (−650 to −700 g C m2 yr−1) and least at the Dwarf Cypress (−400 to −450 g C m2 yr−1). Changes in NEE were clearly a function of seasonality in solar insolation, air temperature and flooding, which suppressed heterotrophic soil respiration. We also note that changes in the satellite-derived enhanced vegetation index (EVI) served as a useful surrogate for changes in NEE at these forested wetland sites.

  8. Differential responses of net ecosystem exchange of carbon dioxide to light and temperature between spring and neap tides in subtropical mangrove forests.

    PubMed

    Li, Qing; Lu, Weizhi; Chen, Hui; Luo, Yiqi; Lin, Guanghui

    2014-01-01

    The eddy flux data with field records of tidal water inundation depths of the year 2010 from two mangroves forests in southern China were analyzed to investigate the tidal effect on mangrove carbon cycle. We compared the net ecosystem exchange (NEE) and its responses to light and temperature, respectively, between spring tide and neap tide inundation periods. For the most time of the year 2010, higher daytime NEE values were found during spring tides than during neap tides at both study sites. Regression analysis of daytime NEE to photosynthetically active radiation (PAR) using the Landsberg model showed increased sensitivity of NEE to PAR with higher maximum photosynthetic rate during spring tides than neap tides. In contrast, the light compensation points acquired from the regression function of the Landsberg model were smaller during spring tides than neap tides in most months. The dependence of nighttime NEE on soil temperature was lower under spring tide than under neap tides. All these results above indicated that ecosystem carbon uptake rates of mangrove forests were strengthened, while ecosystem respirations were inhibited during spring tides in comparison with those during neap tides, which needs to be considered in modeling mangrove ecosystem carbon cycle under future sea level rise scenarios.

  9. Estimating carbon dioxide fluxes from temperate mountain grasslands using broad-band vegetation indices

    NASA Astrophysics Data System (ADS)

    Wohlfahrt, G.; Pilloni, S.; Hörtnagl, L.; Hammerle, A.

    2009-11-01

    The broad-band normalised difference vegetation index (NDVI) and the simple ratio (SR) were calculated from measurements of reflectance of photosynthetically active and short-wave radiation at two temperate mountain grasslands in Austria and related to the net ecosystem CO2 exchange (NEE) measured concurrently by means of the eddy covariance method. There was no significant statistical difference between the relationships of midday mean NEE with narrow- and broad-band NDVI and SR, measured during and calculated for that same time window, respectively. The skill of broad-band NDVI and SR in predicting CO2 fluxes was higher for metrics dominated by gross photosynthesis and lowest for ecosystem respiration, with NEE in between. A method based on a simple light response model whose parameters were parameterised based on broad-band NDVI allowed to improve predictions of daily NEE and is suggested to hold promise for filling gaps in the NEE time series. Relationships of CO2 flux metrics with broad-band NDVI and SR however generally differed between the two studied grassland sites indicting an influence of additional factors not yet accounted for.

  10. Estimating carbon dioxide fluxes from temperate mountain grasslands using broad-band vegetation indices

    NASA Astrophysics Data System (ADS)

    Wohlfahrt, G.; Pilloni, S.; Hörtnagl, L.; Hammerle, A.

    2010-02-01

    The broad-band normalised difference vegetation index (NDVI) and the simple ratio (SR) were calculated from measurements of reflectance of photosynthetically active and short-wave radiation at two temperate mountain grasslands in Austria and related to the net ecosystem CO2 exchange (NEE) measured concurrently by means of the eddy covariance method. There was no significant statistical difference between the relationships of midday mean NEE with narrow- and broad-band NDVI and SR, measured during and calculated for that same time window, respectively. The skill of broad-band NDVI and SR in predicting CO2 fluxes was higher for metrics dominated by gross photosynthesis and lowest for ecosystem respiration, with NEE in between. A method based on a simple light response model whose parameters were parameterised based on broad-band NDVI allowed to improve predictions of daily NEE and is suggested to hold promise for filling gaps in the NEE time series. Relationships of CO2 flux metrics with broad-band NDVI and SR however generally differed between the two studied grassland sites indicting an influence of additional factors not yet accounted for.

  11. Ecosystem carbon exchange in response to locust outbreaks in a temperate steppe.

    PubMed

    Song, Jian; Wu, Dandan; Shao, Pengshuai; Hui, Dafeng; Wan, Shiqiang

    2015-06-01

    It is predicted that locust outbreaks will occur more frequently under future climate change scenarios, with consequent effects on ecological goods and services. A field manipulative experiment was conducted to examine the responses of gross ecosystem productivity (GEP), net ecosystem carbon dioxide (CO2) exchange (NEE), ecosystem respiration (ER), and soil respiration (SR) to locust outbreaks in a temperate steppe of northern China from 2010 to 2011. Two processes related to locust outbreaks, natural locust feeding and carcass deposition, were mimicked by clipping 80 % of aboveground biomass and adding locust carcasses, respectively. Ecosystem carbon (C) exchange (i.e., GEP, NEE, ER, and SR) was suppressed by locust feeding in 2010, but stimulated by locust carcass deposition in both years (except SR in 2011). Experimental locust outbreaks (i.e., clipping plus locust carcass addition) decreased GEP and NEE in 2010 whereas they increased GEP, NEE, and ER in 2011, leading to neutral changes in GEP, NEE, and SR across the 2 years. The responses of ecosystem C exchange could have been due to the changes in soil ammonium nitrogen, community cover, and aboveground net primary productivity. Our findings of the transient and neutral changes in ecosystem C cycling under locust outbreaks highlight the importance of resistance, resilience, and stability of the temperate steppe in maintaining reliable ecosystem services, and facilitate the projections of ecosystem functioning in response to natural disturbance and climate change.

  12. Differential Responses of Net Ecosystem Exchange of Carbon Dioxide to Light and Temperature between Spring and Neap Tides in Subtropical Mangrove Forests

    PubMed Central

    Li, Qing; Lu, Weizhi; Chen, Hui; Luo, Yiqi; Lin, Guanghui

    2014-01-01

    The eddy flux data with field records of tidal water inundation depths of the year 2010 from two mangroves forests in southern China were analyzed to investigate the tidal effect on mangrove carbon cycle. We compared the net ecosystem exchange (NEE) and its responses to light and temperature, respectively, between spring tide and neap tide inundation periods. For the most time of the year 2010, higher daytime NEE values were found during spring tides than during neap tides at both study sites. Regression analysis of daytime NEE to photosynthetically active radiation (PAR) using the Landsberg model showed increased sensitivity of NEE to PAR with higher maximum photosynthetic rate during spring tides than neap tides. In contrast, the light compensation points acquired from the regression function of the Landsberg model were smaller during spring tides than neap tides in most months. The dependence of nighttime NEE on soil temperature was lower under spring tide than under neap tides. All these results above indicated that ecosystem carbon uptake rates of mangrove forests were strengthened, while ecosystem respirations were inhibited during spring tides in comparison with those during neap tides, which needs to be considered in modeling mangrove ecosystem carbon cycle under future sea level rise scenarios. PMID:25133267

  13. Upscaling diurnal cycles of carbon fluxes

    NASA Astrophysics Data System (ADS)

    Bodesheim, Paul; Jung, Martin; Mahecha, Miguel; Reichstein, Markus

    2017-04-01

    Carbon fluxes like Gross Primary Production (GPP) and Net Ecosystem Exchange (NEE) are important variables for studying interactions between the atmosphere and the biosphere in different ecosystems. They are typically derived from measurements at Eddy covariance towers and the FLUXNET global network consists of hundreds of such sites. In order to diagnose global GPP and NEE patterns from FLUXNET, upscaling approaches have been used in the past to extrapolate the site measurements to continental and global scale. However, respective products have a daily or monthly temporal resolution and do not allow for analyzing patterns related to diurnal variations of GPP and NEE. To raise these upscaling approaches to the next level, we present our first results on upscaling diurnal cycles of GPP and NEE with half-hourly resolution. We use random forest regression models to estimate the relationship between predictor variables and fluxes based on more than four million half-hourly observations from FLUXNET sites. We have developed and tested two approaches that overcome the mismatch in the temporal resolution between predictor variables at daily resolution and fluxes at half-hourly resolution. Based on thorough leave-one-site-out cross-validation we show that the approach works very well. Finally, we used the trained models for computing global products of half-hourly GPP and NEE that cover the years 2001 to 2014 and present global patterns of diurnal carbon flux variations derived from the upscaling approach.

  14. Burn severity influences postfire CO2 exchange in arctic tundra.

    PubMed

    Rocha, Adrian V; Shaver, Gaius R

    2011-03-01

    Burned landscapes present several challenges to quantifying landscape carbon balance. Fire scars are composed of a mosaic of patches that differ in burn severity, which may influence postfire carbon budgets through damage to vegetation and carbon stocks. We deployed three eddy covariance towers along a burn severity gradient (i.e., severely burned, moderately burned, and unburned tundra) to monitor postfire net ecosystem exchange of CO2 (NEE) within the large 2007 Anaktuvuk River fire scar in Alaska, USA, during the summer of 2008. Remote sensing data from the MODerate resolution Imaging Spectroradiometer (MODIS) was used to assess the spatial representativeness of the tower sites and parameterize a NEE model that was used to scale tower measurements to the landscape. The tower sites had similar vegetation and reflectance properties prior to the Anaktuvuk River fire and represented the range of surface conditions observed within the fire scar during the 2008 summer. Burn severity influenced a variety of surface properties, including residual organic matter, plant mortality, and vegetation recovery, which in turn determined postfire NEE. Carbon sequestration decreased with increased burn severity and was largely controlled by decreases in canopy photosynthesis. The MODIS two-band enhanced vegetation index (EVI2) monitored the seasonal course of surface greenness and explained 86% of the variability in NEE across the burn severity gradient. We demonstrate that understanding the relationship between burn severity, surface reflectance, and NEE is critical for estimating the overall postfire carbon balance of the Anaktuvuk River fire scar.

  15. Growing season net ecosystem CO2 exchange of two desert ecosystems with alkaline soils in Kazakhstan

    PubMed Central

    Li, Longhui; Chen, Xi; van der Tol, Christiaan; Luo, Geping; Su, Zhongbo

    2014-01-01

    Central Asia is covered by vast desert ecosystems, and the majority of these ecosystems have alkaline soils. Their contribution to global net ecosystem CO2 exchange (NEE) is of significance simply because of their immense spatial extent. Some of the latest research reported considerable abiotic CO2 absorption by alkaline soil, but the rate of CO2 absorption has been questioned by peer communities. To investigate the issue of carbon cycle in Central Asian desert ecosystems with alkaline soils, we have measured the NEE using eddy covariance (EC) method at two alkaline sites during growing season in Kazakhstan. The diurnal course of mean monthly NEE followed a clear sinusoidal pattern during growing season at both sites. Both sites showed significant net carbon uptake during daytime on sunny days with high photosynthetically active radiation (PAR) but net carbon loss at nighttime and on cloudy and rainy days. NEE has strong dependency on PAR and the response of NEE to precipitation resulted in an initial and significant carbon release to the atmosphere, similar to other ecosystems. These findings indicate that biotic processes dominated the carbon processes, and the contribution of abiotic carbon process to net ecosystem CO2 exchange may be trivial in alkaline soil desert ecosystems over Central Asia. PMID:24455157

  16. Rainfall regulates the impact of elevated atmospheric CO2 on carbon balance in Chesapeake Bay wetland and Florida Scrub Oak.

    NASA Astrophysics Data System (ADS)

    Drake, B. G.; Rasse, D.

    2004-12-01

    Elevated atmospheric CO2 (Ca) is expected to stimulate ecosystem carbon assimilation and reduce stomatal conductance and transpiration in native ecosystems but the interaction between these effects and water and nutrient supply is highly uncertain. We report results of measurements of Net Ecosystem CO2 Exchange (NEE) from an 18 year study of the effects of elevated Ca on a Chesapeake Bay Maryland wetland and a seven year study in a scrub oak ecosystem Cape Canaveral, Florida exposed to ambient or elevated (normal ambient plus 350 ppm) Ca in open top chambers which were also used to measure NEE. Although acclimation of photosynthesis was commonly observed, elevated Ca often caused a stimulation of photosynthesis of 35-100 percent. Elevated Ca stimulated NEE was the same or greater than NEE in sites at normal ambient Ca but inter-annual variation in the effect was large. Stimulation of NEE by elevated Ca was linearly correlated with rainfall. These results suggest that the inter-annual variation in the effects of elevated Ca on ecosystem carbon balance were due to the availability of water and not to other factors such as nitrogen supply.

  17. Carbon exchange between the atmosphere and subtropical forested cypress and pine wetlands

    NASA Astrophysics Data System (ADS)

    Shoemaker, W. B.; Anderson, F.; Barr, J. G.; Graham, S. L.; Botkin, D. B.

    2015-04-01

    Carbon dioxide exchange between the atmosphere and forested subtropical wetlands is largely unknown. Here we report a first step in characterizing this atmospheric-ecosystem carbon (C) exchange, for cypress strands and pine forests in the Greater Everglades of Florida as measured with eddy covariance methods at three locations (Cypress Swamp, Dwarf Cypress and Pine Upland) for 2 years. Links between water and C cycles are also examined at these three sites, as are methane emission measured only at the Dwarf Cypress site. Each forested wetland showed net C uptake from the atmosphere both monthly and annually, as indicated by the net ecosystem exchange (NEE) of carbon dioxide (CO2). For this study, NEE is the difference between photosynthesis and respiration, with negative values representing uptake from the atmosphere that is retained in the ecosystem or transported laterally via overland flow (unmeasured for this study). Atmospheric C uptake (NEE) was greatest at the Cypress Swampp (-900 to -1000 g C m2 yr-1), moderate at the Pine Upland (-650 to -700 g C m2 yr-1) and least at the Dwarf Cypress (-400 to -450 g C m2 yr-1). Changes in NEE were clearly a function of seasonality in solar insolation, air temperature and flooding, which suppressed heterotrophic soil respiration. We also note that changes in the satellite-derived enhanced vegetation index (EVI) served as a useful surrogate for changes in NEE at these forested wetland sites.

  18. Growing season net ecosystem CO2 exchange of two desert ecosystems with alkaline soils in Kazakhstan.

    PubMed

    Li, Longhui; Chen, Xi; van der Tol, Christiaan; Luo, Geping; Su, Zhongbo

    2014-01-01

    Central Asia is covered by vast desert ecosystems, and the majority of these ecosystems have alkaline soils. Their contribution to global net ecosystem CO2 exchange (NEE) is of significance simply because of their immense spatial extent. Some of the latest research reported considerable abiotic CO2 absorption by alkaline soil, but the rate of CO2 absorption has been questioned by peer communities. To investigate the issue of carbon cycle in Central Asian desert ecosystems with alkaline soils, we have measured the NEE using eddy covariance (EC) method at two alkaline sites during growing season in Kazakhstan. The diurnal course of mean monthly NEE followed a clear sinusoidal pattern during growing season at both sites. Both sites showed significant net carbon uptake during daytime on sunny days with high photosynthetically active radiation (PAR) but net carbon loss at nighttime and on cloudy and rainy days. NEE has strong dependency on PAR and the response of NEE to precipitation resulted in an initial and significant carbon release to the atmosphere, similar to other ecosystems. These findings indicate that biotic processes dominated the carbon processes, and the contribution of abiotic carbon process to net ecosystem CO2 exchange may be trivial in alkaline soil desert ecosystems over Central Asia.

  19. Differential responses of carbon and water vapor fluxes to climate among evergreen needleleaf forests in the USA

    DOE PAGES

    Wagle, Pradeep; Xiao, Xiangming; Kolb, Thomas E.; ...

    2016-05-31

    Here, understanding the differences in carbon and water vapor fluxes of spatially distributed evergreen needleleaf forests (ENFs) is crucial for accurately estimating regional or global carbon and water budgets and when predicting the responses of ENFs to current and future climate. We compared the fluxes of ten AmeriFlux ENF sites to investigate cross-site variability in net ecosystem exchange of carbon (NEE), gross primary production (GPP), and evapotranspiration (ET). We used wavelet cross-correlation analysis to examine responses of NEE and ET to common climatic drivers over multiple timescales and also determined optimum values of air temperature (T a) and vapor pressuremore » deficit (VPD) for NEE and ET.« less

  20. Disentangling leaf area and environmental effects on the response of the net ecosystem CO2 exchange to diffuse radiation.

    PubMed

    Wohlfahrt, Georg; Hammerle, Albin; Haslwanter, Alois; Bahn, Michael; Tappeiner, Ulrike; Cernusca, Alexander

    2008-08-01

    There is an ongoing discussion about why the net ecosystem CO2 exchange (NEE) of some ecosystems is less sensitive to diffuse radiation than others and about the role other environmental factors play in determining the response of NEE to diffuse radiation. Using a six-year data set from a temperate mountain grassland in Austria we show that differences between ecosystems may be reconciled based on their green area index (GAI; square meter green plant area per square meter ground area) - the sensitivity to diffuse radiation increasing with GAI. Our data suggest diffuse radiation to have a negligible influence on NEE below a GAI of 2 m(2) m(-2). Changes in air/soil temperature and air humidity concurrent with the fraction of diffuse radiation were found to amplify the sensitivity of the investigated temperate mountain grassland ecosystem to diffuse radiation.

  1. An annotated catalogue of the Iranian Euphorinae, Gnamptodontinae, Helconinae, Hormiinae and Rhysipolinae (Hymenoptera: Braconidae).

    PubMed

    Gadallah, Neveen S; Ghahari, Hassan; Achterberg, Kees Van

    2016-01-28

    The Iranian species diversity of five braconid subfamilies, Euphorinae (54 species in 16 genera and 8 tribes), Gnamptodontinae (4 species in 1 genus and 1 tribe), Helconinae (9 species in 5 genera and 2 tribes), Hormiinae (8 species in 4 genera and 2 tribe) and Rhysipolinae (3 species in 2 genera) are summarized in this catalogue. A faunistic list is given comprising both local and global distribution of each species under study as well as host records. In the present study ten new records are added to the Iranian fauna: Centistes (Ancylocentrus) ater (Nees), Centistes cuspidatus (Haliday), Meteorus affinis (Wesmael), Meteorus rufus (DeGeer), Microctonus brevicollis (Haliday), Microctonus falciger Ruthe, Peristenus nitidus (Curtis) (Euphorinae), Aspicolpus carinator (Nees), Diospilus capito (Nees) and Diospilus productus Marshall (Helconinae s.l.). Euphorus pseudomitis Hedwig, 1957 is transferred to the subfamily Hormiinae and Hormisca pseudomitis (Hedwig, 1957) is a new combination.

  2. New constraints on Northern Hemisphere growing season net flux

    NASA Astrophysics Data System (ADS)

    Yang, Z.; Washenfelder, R. A.; Keppel-Aleks, G.; Krakauer, N. Y.; Randerson, J. T.; Tans, P. P.; Sweeney, C.; Wennberg, P. O.

    2007-06-01

    Observations of the column-averaged dry molar mixing ratio of CO2 above both Park Falls, Wisconsin and Kitt Peak, Arizona, together with partial columns derived from aircraft profiles over Eurasia and North America are used to estimate the seasonal integral of net ecosystem exchange (NEE) between the atmosphere and the terrestrial biosphere in the Northern Hemisphere. We find that NEE is ~25% larger than predicted by the Carnegie Ames Stanford Approach (CASA) model. We show that the estimates of NEE may have been biased low by too weak vertical mixing in the transport models used to infer seasonal changes in Northern Hemisphere CO2 mass from the surface measurements of CO2 mixing ratio.

  3. Disentangling leaf area and environmental effects on the response of the net ecosystem CO2 exchange to diffuse radiation

    PubMed Central

    Wohlfahrt, Georg; Hammerle, Albin; Haslwanter, Alois; Bahn, Michael; Tappeiner, Ulrike; Cernusca, Alexander

    2013-01-01

    There is an ongoing discussion about why the net ecosystem CO2 exchange (NEE) of some ecosystems is less sensitive to diffuse radiation than others and about the role other environmental factors play in determining the response of NEE to diffuse radiation. Using a six-year data set from a temperate mountain grassland in Austria we show that differences between ecosystems may be reconciled based on their green area index (GAI; square meter green plant area per square meter ground area) - the sensitivity to diffuse radiation increasing with GAI. Our data suggest diffuse radiation to have a negligible influence on NEE below a GAI of 2 m2 m−2. Changes in air/soil temperature and air humidity concurrent with the fraction of diffuse radiation were found to amplify the sensitivity of the investigated temperate mountain grassland ecosystem to diffuse radiation. PMID:24347740

  4. [CO2 flux characteristics and their influence on the carbon budget of a larch plantation in Maoershan region of Northeast China].

    PubMed

    Qiu, Ling; Zu, Yuan-Gang; Wang, Wen-Jie; Sun, Wei; Su, Dong-Xue; Zheng, Guang-Yu

    2011-01-01

    From January to December 2008, the CO2 flux in a larch plantation (Larix gmeilinii) in Maoershan region of Shangzhi County, Heilongliang Province was measured by eddy covanance method, and the diurnal changes of leaf photosynthetic rate were measured in growth season (from May to October). There existed differences in the net ecosystem exchange (NEE) of the plantation in different time periods under the effects of environmental factors. In the afternoon (12:00-24:00), the NEE changed more slowly with the variation of vapor pressure deficit (VPD) than in the morning (0:00-12:00); and in the morning, tbe light use efficiency was 0.6284 mol x mol(-1), 14% more than that in afternoon. The NEE increased with increasing temperature, and the increment in the morning was 50% higher than that in the afternoon (air temperature > 15 degrees C). These differences in responding to environmental changes led to 88% NEE implemented in the morning, and only 12% NEE implemented in the afternoon. The annual gross ecosystem productivity (GEP) in the morning took a percentage of 60%, and that in afternoon took 40%. These findings were supported by the observation at leaf level, i.e., on average of whole growth season, the leaf photosynthetic capacity in the morning was over 2-fold higher than that in afternoon. Generally, the annual NEE, ecosystem respiration (Re), and GEP of the plantation in 2008 were 263-264 g C x m(-2), 718-725 g C x m(-2), and 981-989 g C x m(-2), respectively.

  5. Drivers of long-term variability in CO2 net ecosystem exchange in a temperate peatland

    NASA Astrophysics Data System (ADS)

    Helfter, C.; Campbell, C.; Dinsmore, K. J.; Drewer, J.; Coyle, M.; Anderson, M.; Skiba, U.; Nemitz, E.; Billett, M. F.; Sutton, M. A.

    2014-10-01

    Land-atmosphere exchange of carbon dioxide (CO2) in peatlands exhibits marked seasonal and inter-annual variability, which subsequently affects the carbon sink strength of catchments across multiple temporal scales. Long-term studies are needed to fully capture the natural variability and therefore identify the key hydrometeorological drivers in the net ecosystem exchange (NEE) of CO2. NEE has been measured continuously by eddy-covariance at Auchencorth Moss, a temperate lowland peatland in central Scotland, since 2002. Hence this is one of the longest peatland NEE studies to date. For 11 yr, the site was a consistent, yet variable, atmospheric CO2 sink ranging from -5.2 to -135.9 g CO2-C m-2 yr-1 (mean of -64.1 ± 33.6 g CO2-C m-2 yr-1). Inter-annual variability in NEE was positively correlated to the length of the growing season. Mean winter air temperature explained 87% of the inter-annual variability in the sink strength of the following summer, indicating a phenological memory-effect. Plant productivity exhibited a marked hysteresis with respect to photosynthetically active radiation (PAR) over the growing season, indicative of two separate growth regimes. Ecosystem respiration (Reco) and gross primary productivity (GPP) were closely correlated (ratio 0.74), suggesting that autotrophic processes were dominant. Whilst the site was wet most of the year (water table depth <5 cm) there were indications that heterotrophic respiration was enhanced by drought, which also depressed GPP. NEE was compared to 5 other peatland sites which have published long-term NEE records. The CO2 uptake rate during the growing season was comparable to 3 other European sites, however the emission rate during the dormant season was significantly higher.

  6. On the difference in the net ecosystem exchange of CO2 between deciduous and evergreen forests in the southeastern United States.

    PubMed

    Novick, Kimberly A; Oishi, A Christopher; Ward, Eric J; Siqueira, Mario B S; Juang, Jehn-Yih; Stoy, Paul C

    2015-02-01

    The southeastern United States is experiencing a rapid regional increase in the ratio of pine to deciduous forest ecosystems at the same time it is experiencing changes in climate. This study is focused on exploring how these shifts will affect the carbon sink capacity of southeastern US forests, which we show here are among the strongest carbon sinks in the continental United States. Using eight-year-long eddy covariance records collected above a hardwood deciduous forest (HW) and a pine plantation (PP) co-located in North Carolina, USA, we show that the net ecosystem exchange of CO2 (NEE) was more variable in PP, contributing to variability in the difference in NEE between the two sites (ΔNEE) at a range of timescales, including the interannual timescale. Because the variability in evapotranspiration (ET) was nearly identical across the two sites over a range of timescales, the factors that determined the variability in ΔNEE were dominated by those that tend to decouple NEE from ET. One such factor was water use efficiency, which changed dramatically in response to drought and also tended to increase monotonically in nondrought years (P < 0.001 in PP). Factors that vary over seasonal timescales were strong determinants of the NEE in the HW site; however, seasonality was less important in the PP site, where significant amounts of carbon were assimilated outside of the active season, representing an important advantage of evergreen trees in warm, temperate climates. Additional variability in the fluxes at long-time scales may be attributable to slowly evolving factors, including canopy structure and increases in dormant season air temperature. Taken together, study results suggest that the carbon sink in the southeastern United States may become more variable in the future, owing to a predicted increase in drought frequency and an increase in the fractional cover of southern pines. © 2014 John Wiley & Sons Ltd.

  7. A 12-year record reveals pre-growing season temperature and water table level threshold effects on the net carbon dioxide exchange in a boreal fen

    NASA Astrophysics Data System (ADS)

    Peichl, Matthias; Öquist, Mats; Ottosson Löfvenius, Mikaell; Ilstedt, Ulrik; Sagerfors, Jörgen; Grelle, Achim; Lindroth, Anders; Nilsson, Mats B.

    2014-05-01

    This study uses a 12-year time series (2001-2012) of eddy covariance measurements to investigate the long-term net ecosystem exchange (NEE) of carbon dioxide (CO2) and inter-annual variations in relation to abiotic drivers in a boreal fen in northern Sweden. The peatland was a sink for atmospheric CO2 in each of the twelve study years with a 12-year average (± standard deviation) NEE of -58 ± 21 g C m-2 yr-1. For ten out of twelve years, the cumulative annual NEE was within a range of -42 to -79 g C m-2 yr-1 suggesting a general state of resilience of NEE to moderate inter-annual climate variations. However, the annual NEE of -18 and -106 g C m-2 yr-1 in 2006 and 2008, respectively, diverged considerably from this common range. The lower annual CO2 uptake in 2006 was mainly due to late summer emissions related to an exceptional drop in water table level (WTL). A positive relationship (R 2 = 0.65) between pre-growing season (January to April) air temperature (Ta) and summer (June to July) gross ecosystem production (GEP) was observed. We suggest that enhanced GEP due to mild pre-growing season air temperature in combination with air temperature constraints on ecosystem respiration (ER) during the following cooler summer explained most of the greater net CO2 uptake in 2008. Differences in the annual and growing season means of other abiotic variables (e.g. radiation, vapor pressure deficit, precipitation) and growing season properties (i.e. start date, end date, length) were unable to explain the inter-annual variations of NEE. Overall, our findings suggest that this boreal fen acts as a persistent contemporary sink for atmospheric CO2 that is, however, susceptible to severe anomalies in WTL and pre-growing season air temperature associated with predicted changes in climate patterns for the boreal region.

  8. A 12-year record reveals pre-growing season temperature and water table level threshold effects on the net carbon dioxide uptake in a boreal fen

    NASA Astrophysics Data System (ADS)

    Peichl, Matthias; Öquist, Mats; Ottosson-Löfvenius, Mikaell; Ilstedt, Ulrik; Sagerfors, Jörgen; Grelle, Achim; Lindroth, Anders; Nilsson, Mats

    2014-05-01

    This study uses a 12-year time series (2001-2012) of eddy covariance measurements to investigate the long-term net ecosystem exchange (NEE) of carbon dioxide (CO2) and inter-annual variations in relation to abiotic drivers in a boreal fen in Northern Sweden. The peatland was a sink for atmospheric CO2 in each of the twelve study years with a 12-year average (± standard deviation) NEE of -58 ± 21 g C m-2 y-1. For ten out of twelve years, the cumulative annual NEE was within a range of -42 to -79 g C m-2 y-1 suggesting a general state of resilience of NEE to moderate inter-annual climate variations. In two years however, the annual NEE diverged considerably from this common range with -18 and -106 g C m-2 y-1 measured in 2006 and 2008, respectively. The lower annual CO2 uptake in 2006 was mainly due to late summer emissions related to an exceptional drop in water table level. A positive relationship (r2 = 0.65) between pre-growing season (January to April) air temperature and summer (June to July) gross ecosystem production (GEP) was observed. We suggest that enhanced GEP due to mild pre-growing season air temperature in combination with air temperature constraints on ecosystem respiration (ER) during the following cooler summer explained the greater net CO2 uptake in 2008. Differences in the annual and growing season means of other abiotic variables (e.g. radiation, vapor pressure deficit, precipitation) and growing season properties (i.e. start date, end date, length) were unable to explain the inter-annual variations of NEE. Overall, our findings suggest that this boreal fen acts as a persistent contemporary sink for atmospheric CO2 that is however susceptible to severe anomalies in water table level and pre-growing season air temperature associated with predicted changes in climate patterns for the boreal region.

  9. Impact of cloudiness on net ecosystem exchange of carbon dioxide in different types of forest ecosystems in China

    NASA Astrophysics Data System (ADS)

    Zhang, M.; Yu, G.-R.; Zhang, L.-M.; Sun, X.-M.; Wen, X.-F.; Han, S.-J.; Yan, J.-H.

    2009-08-01

    Clouds can significantly affect carbon uptake of forest ecosystems by affecting incoming solar radiation on the ground, temperature and other environmental factors. In this study, we analyzed the effects of cloudiness on the net ecosystem exchange of carbon dioxide (NEE) of a temperate broad-leaved Korean pine mixed forest at Changbaishan (CBS) and a subtropical evergreen broad-leaved forest at Dinghushan (DHS) of ChinaFLUX, based on the flux data obtained during June-August from 2003 to 2006. The results showed that the response of the NEE of forest ecosystem to photosynthetically active radiation (PAR) was different under clear sky and cloudy sky conditions, and this difference was not consistent between CBS and DHS. Compared with clear skies, light-saturated maximum photosynthetic rate (Pec,max) of CBS during mid-growing season (from June to August) was respectively enhanced by 34%, 25%, 4% and 11% on cloudy skies in 2003, 2004, 2005 and 2006; however, Pec,max of DHS was higher under clear skies than under cloudy skies from 2004 to 2006. NEE of forests at CBS reached its maximum when the clearness index (kt) was between 0.4 and 0.6, and the NEE decreased obviously when kt exceeded 0.6. Compare with CBS, although NEE of forest at DHS tended to the maximum when kt varied between 0.4 and 0.6, the NEE did not decrease noticeably when kt exceeded 0.6. The results indicated that cloudy sky conditions were more beneficial to carbon uptake for the temperate forest ecosystem rather than for the subtropical forest ecosystem. This is due to the fact that the non-saturating light conditions and increase of diffuse radiation were more beneficial to photosynthesis, and the reduced temperature was more conducive to decreasing the ecosystem respiration in temperate forest ecosystems under cloudy sky conditions. This phenomenon is important to evaluate carbon uptake of temperate forests under climate change conditions.

  10. Impact of cloudiness on net ecosystem exchange of carbon dioxide in different types of forest ecosystems in China

    NASA Astrophysics Data System (ADS)

    Zhang, M.; Yu, G.-R.; Zhang, L.-M.; Sun, X.-M.; Wen, X.-F.; Han, S.-J.; Yan, J.-H.

    2010-02-01

    Clouds can significantly affect carbon exchange process between forest ecosystems and the atmosphere by influencing the quantity and quality of solar radiation received by ecosystem's surface and other environmental factors. In this study, we analyzed the effects of cloudiness on net ecosystem exchange of carbon dioxide (NEE) in a temperate broad-leaved Korean pine mixed forest at Changbaishan (CBS) and a subtropical evergreen broad-leaved forest at Dinghushan (DHS), based on the flux data obtained during June-August from 2003 to 2006. The results showed that the response of NEE of forest ecosystems to photosynthetically active radiation (PAR) differed under clear skies and cloudy skies. Compared with clear skies, the light-saturated maximum photosynthetic rate (Pec,max) at CBS under cloudy skies during mid-growing season (from June to August) increased by 34%, 25%, 4% and 11% in 2003, 2004, 2005 and 2006, respectively. In contrast, Pec,max of the forest ecosystem at DHS was higher under clear skies than under cloudy skies from 2004 to 2006. When the clearness index (kt) ranged between 0.4 and 0.6, the NEE reached its maximum at both CBS and DHS. However, the NEE decreased more dramatically at CBS than at DHS when kt exceeded 0.6. The results indicate that cloudy sky conditions are beneficial to net carbon uptake in the temperate forest ecosystem and the subtropical forest ecosystem. Under clear skies, vapor pressure deficit (VPD) and air temperature increased due to strong light. These environmental conditions led to greater decrease in gross ecosystem photosynthesis (GEP) and greater increase in ecosystem respiration (Re) at CBS than at DHS. As a result, clear sky conditions caused more reduction of NEE in the temperate forest ecosystem than in the subtropical forest ecosystem. The response of NEE of different forest ecosystems to the changes in cloudiness is an important factor that should be included in evaluating regional carbon budgets under climate change

  11. Toward Verifying Fossil Fuel CO2 Emissions with the CMAQ Model: Motivation, Model Description and Initial Simulation

    SciTech Connect

    Liu, Zhen; Bambha, Ray P.; Pinto, Joseph P.; Zeng, Tao; Boylan, Jim; Huang, Maoyi; Lei, Huimin; Zhao, Chun; Liu, Shishi; Mao, Jiafu; Schwalm, Christopher R.; Shi, Xiaoying; Wei, Yaxing; Michelsen, Hope A.

    2014-03-14

    Motivated by the urgent need for emission verification of CO2 and other greenhouse gases, we have developed regional CO2 simulation with CMAQ over the contiguous U.S. Model sensitivity experiments have been performed using three different sets of inputs for net ecosystem exchange (NEE) and two fossil fuel emission inventories, to understand the roles of fossil fuel emissions, atmosphere-biosphere exchange and transport in regulating the spatial and diurnal variability of CO2 near the surface, and to characterize the well-known ‘signal-to-noise’ problem, i.e. the interference from the biosphere on the interpretation of atmospheric CO2 observations. It is found that differences in the meteorological conditions for different urban areas strongly contribute to the contrast in concentrations. The uncertainty of NEE, as measured by the difference among the three different NEE inputs, has notable impact on regional distribution of CO2 simulated by CMAQ. Larger NEE uncertainty and impact are found over eastern U.S. urban areas than along the western coast. A comparison with tower CO2 measurements at Boulder Atmospheric Observatory (BAO) shows that the CMAQ model using hourly varied and high-resolution CO2 emission from the Vulcan inventory and CarbonTracker optimized NEE reasonably reproduce the observed diurnal profile, whereas switching to different NEE inputs significantly degrades the model performance. Spatial distribution of CO2 is found to correlate with NOx, SO2 and CO, due to their similarity in emission sources and transport processes. These initial results from CMAQ demonstrate the power of a state-of-the art CTM in helping interpret CO2 observations and verify fossil fuel emissions. The ability to simulate CO2 in CMAQ will also facilitate investigations of the utility of traditionally regulated pollutants and other species as tracers to CO2 source attribution.

  12. Partitioning interannual variability in net ecosystem exchange between climatic variability and functional change.

    PubMed

    Hui, Dafeng; Luo, Yiqi; Katul, Gabriel

    2003-05-01

    Interannual variability (IAV) in net ecosystem exchange of carbon (NEE) is a critical factor in projections of future ecosystem changes. However, our understanding of IAV is limited because of the difficulty in isolating its numerous causes. We proposed that IAV in NEE is primarily caused by climatic variability, through its direct effects on photosynthesis and respiration and through its indirect effects on carbon fluxes (i.e., the parameters that govern photosynthesis and respiration), hereafter called functional change. We employed a homogeneity-of-slopes model to identify the functional change contributing to IAV in NEE and nighttime ecosystem respiration (RE). The model uses multiple regression analysis to relate NEE and RE with climatic variables for individual years and for all years. If the use of different slopes for each year significantly improves the model fitting compared to the use of one slope for all years, we consider that functional change exists, at least on annual time scales. With the functional change detected, we then partition the observed variation in NEE or RE to four components, namely, the functional change, the direct effect of interannual climatic variability, the direct effect of seasonal climatic variation, and random error. Application of this approach to a data set collected at the Duke Forest AmeriFlux site from August 1997 to December 2001 indicated that functional change, interannual climatic variability, seasonal climatic variation and random error explained 9.9, 8.9, 59.9 and 21.3%, respectively, of the observed variation in NEE and 13.1, 5.0, 38.1 and 43.8%, respectively, of the observed variation in RE.

  13. Long term trend and interannual variability of land carbon uptake—the attribution and processes

    NASA Astrophysics Data System (ADS)

    Fu, Zheng; Dong, Jinwei; Zhou, Yuke; Stoy, Paul C.; Niu, Shuli

    2017-01-01

    Ecosystem carbon (C) uptake in terrestrial ecosystems has increased over the past five decades, but with large interannual variability (IAV). However, we are not clear on the attribution and the processes that control the long-term trend and IAV of land C uptake. Using atmospheric inversion net ecosystem exchange (NEE) data, we quantified the trend and IAV of NEE across the globe, the Northern Hemisphere (NH), and the Southern Hemisphere (SH), and decomposed NEE into carbon uptake amplitude and duration during each year from 1979–2013. We found the NH rather than the SH determined the IAV, while both hemispheres contributed equivalently to the global NEE trend. Different ecosystems in the NH and SH had differential relative contributions to their trend and IAV. The long-term trends of increased C uptake across the globe and the SH were attributed to both extended duration and increasing amplitude of C uptake. The shortened duration of uptake in the NH partly offsets the effects of increased NEE amplitude, making the net C uptake trend the same as that of the SH. The change in NEE IAV was also linked to changes in the amplitude and duration of uptake, but they worked in different ways in the NH, SH and globe. The fundamental attributions of amplitude and duration of C uptake revealed in this study are helpful to better understand the mechanisms underlying the trend and IAV of land C uptake. Our findings also suggest the critical roles of grassland and croplands in the NH in contributing to the trend and IAV of land C uptake.

  14. Net ecosystem exchange over heterogeneous Arctic tundra: Scaling between chamber and eddy covariance measurements

    NASA Astrophysics Data System (ADS)

    Fox, Andrew M.; Huntley, Brian; Lloyd, Colin R.; Williams, Mathew; Baxter, Robert

    2008-06-01

    Net ecosystem exchange (NEE) was estimated for an area of tundra near Abisko using both eddy covariance (EC) data and chamber measurements. This area of tundra is heterogeneous with six principal elements forming a landscape mosaic. Chamber measurements in patches of the individual mosaic elements were used to model NEE as a function of irradiance and temperature. The area around the EC mast was mapped, and a footprint model was used to simulate the varying source fraction attributable to each mosaic element. Various upscaling approaches were used to estimate NEE for comparison with NEE calculated from the EC observations. The results showed that EC measurements made for such a heterogeneous site are robust to the variations in NEE between mosaic elements that also vary substantially in their source fractions. However, they also revealed a large (˜60%) bias in the absolute magnitude of the cumulative negative NEE for a 40-day study period simulated by various upscaling approaches when compared to the value calculated from the EC observations. The magnitude of this bias, if applied to estimates for the entire tundra region, is substantial in relation to other components of the global carbon budget. Various hypotheses to account for this bias are discussed and, where possible, evaluated. A need is identified for more systematic sampling strategies when performing chamber measurements in order to assess the extent to which subjectivity of chamber location may account for much of the observed bias. If this is the origin of the bias, then upscaling approaches using chamber measurements may generally overestimate CO2 uptake.

  15. Recent variations in Amazon carbon balance driven by climate anomalies

    NASA Astrophysics Data System (ADS)

    Miller, J. B.

    2015-12-01

    Understanding tropical rainforest response to heat and drought is critical for quantifying the effects of climate change on tropical ecosystems, including global climate-carbon feedbacks. Of particular importance for the global carbon budget is net ecosystem exchange of CO2 with the atmosphere (NEE), a metric that represents the total integrated signal of carbon fluxes into and out of ecosystems. Sub-annual and sub-basin NEE estimates have previously been derived from process-based biosphere models, despite often disagreeing with plot-scale observations. Our analysis of airborne CO2 and CO measurements reveals monthly, sub-Basin scale (~106 km2) NEE variations in a framework that is largely independent of bottom-up estimates. As such, our approach provides new insights about tropical forest response to climate. We find acute sensitivity of NEE to daily and monthly climate extremes. In particular, increased central-Amazon NEE was associated with wet-season heat and dry-season drought in 2010. We analyze satellite proxies for photosynthesis and find that suppression of photosynthesis may have contributed to increased carbon loss in the 2010 drought, consistent with recent analysis of plot-scale measurements. In the eastern Amazon, pulses of increased NEE (i.e. net respiration) persisted through 2011, suggesting legacy effects of the drought that occurred in 2010. Regional differences in post-drought recovery in 2011 and 2012 appear related to long-term water availability. These results provide novel evidence of the vulnerability of Amazon carbon stocks to short-term temperature and moisture extremes.

  16. Inter-annual variability in the biosphere-atmosphere exchange of carbon dioxide and water vapor in adjacent pine and hardwood forests: links to drought, disturbance, and seasonality

    NASA Astrophysics Data System (ADS)

    Novick, K. A.; Ward, E. J.; Oishi, A. C.; Stoy, P. C.

    2012-12-01

    Understanding the variation in long-term biosphere-atmosphere fluxes of carbon dioxide and water vapor is necessary to characterize the benefits and services of terrestrial ecosystems, including the highly productive forests of the Southeastern United States. This study quantifies flux variability at inter-annual times scales using eight-year eddy covariance records from two co-located ecosystems in the Duke Forest (North Carolina, USA): a hardwood deciduous forest (HW) and a pine plantation (PP), which together represent the dominant forest types in the region. When averaged across the study period, annual net ecosystem exchange of CO2 (NEE) was similar in PP and HW (NEE = -560 and -520 g C m-2 y-1 in PP and HW, respectively). Variation in annual NEE was high in both ecosystems, but higher in the pine site (CV = 0.38) as compared to the hardwood site (CV = 0.23). Gross ecosystem productivity (GEP) and ecosystem respiration (RE), which together represent the primary components of NEE, were not necessarily more variable in the pine site; however, the coupling between annual GEP and RE was weaker in PP as compared to HW, contributing to higher overall variability in PP NEE. Our results identify at least two factors contributing to this decoupling: 1) an ice storm event, which reduced PP GEP while increasing or having no effect on PP RE, and 2) two severe drought events, which cause large reductions in PP GEP but not RE. Additionally, in both ecosystems, variability in GEP and NEE is strongly related to the length of the active season (r2 = 0.60 - 0.93), a variable reflecting the seasonality of carbon assimilation that is largely independent from patterns of leaf area development.

  17. Response of carbon dioxide exchange to grazing intensity over typical steppes in a semi-arid area of Inner Mongolia

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Liu, Huizhi; Bernhofer, Christian

    2017-05-01

    The eddy covariance technique was used to measure the CO2 flux over four differently grazed Leymus chinensis steppe ecosystems (ungrazed since 1979 (UG79), winter grazed (WG), continuously grazed (CG), and heavily grazed (HG) sites) during four growing seasons (May to September) from 2005 to 2008, to investigate the response of the net ecosystem exchange (NEE) over grassland ecosystems to meteorological factors and grazing intensity. At UG79, the optimal air temperature for the half-hourly NEE occurred between 17 and 20 °C, which was relatively low for semi-arid grasslands. The saturated NEE (NEEsat) and temperature sensitivity coefficient ( Q 10) of ecosystem respiration (RE) exhibited clear seasonal and interannual variations, which increased with canopy development and the soil water content (SWC, at 5 cm). The total NEE values for the growing seasons from 2005 to 2008 were -32.0, -41.5, -66.1, and -89.8 g C m-2, respectively. Both the amounts and distribution of precipitation during the growing season affected the NEE. The effects of grazing on the CO2 flux increased with the grazing intensity. During the peak growth stage, heavy grazing and winter grazing decreased NEEsat and gross primary production (45 % for HG and 34 % for WG) due to leaf area removal. Both RE and Q 10 were clearly reduced by heavy grazing. Heavy grazing changed the ecosystem from a CO2 sink into a CO2 source, and winter grazing reduced the total CO2 uptake by 79 %. In the early growing season, there was no difference in the NEE between CG and UG79. In addition to the grazing intensity, the effects of grazing on the CO2 flux also varied with the vegetation growth stages and SWC.

  18. Fabrication of nanoelectrode ensembles by electrodepositon of Au nanoparticles on single-layer graphene oxide sheets

    NASA Astrophysics Data System (ADS)

    Wang, Zhijuan; Zhang, Juan; Yin, Zongyou; Wu, Shixin; Mandler, Daniel; Zhang, Hua

    2012-03-01

    Nanoelectrode ensembles (NEEs) have been fabricated by the electrodeposition of Au nanoparticles (AuNPs) on single-layer graphene oxide (GO) sheets coated on a glassy carbon electrode (GCE). The fabricated NEEs show a typical sigmoidal shaped voltammetric profile, arising from the low coverage density of AuNPs on GCE and large distance among them, which can be easily controlled by varying the electrodeposition time. As a proof of concept, after the probe HS-DNA is immobilized on the NEEs through the Au-S bonding, the target DNA is detected with the methylene blue intercalator. Our results show that the target DNA can be detected as low as 100 fM, i.e. 0.5 amol DNA in 5 μL solution.Nanoelectrode ensembles (NEEs) have been fabricated by the electrodeposition of Au nanoparticles (AuNPs) on single-layer graphene oxide (GO) sheets coated on a glassy carbon electrode (GCE). The fabricated NEEs show a typical sigmoidal shaped voltammetric profile, arising from the low coverage density of AuNPs on GCE and large distance among them, which can be easily controlled by varying the electrodeposition time. As a proof of concept, after the probe HS-DNA is immobilized on the NEEs through the Au-S bonding, the target DNA is detected with the methylene blue intercalator. Our results show that the target DNA can be detected as low as 100 fM, i.e. 0.5 amol DNA in 5 μL solution. Electronic supplementary information (ESI) available: The results of Raman, XPS, SEM and other electrochemical characterization are provided. See DOI: 10.1039/c2nr30142c

  19. Colonization of a Deglaciated Moraine: Contrasting Patterns of Carbon Uptake and Release from C3 and CAM Plants.

    PubMed

    Varolo, Elisa; Zanotelli, Damiano; Montagnani, Leonardo; Tagliavini, Massimo; Zerbe, Stefan

    2016-01-01

    Current glacier retreat makes vast mountain ranges available for vegetation establishment and growth. As a result, carbon (C) is accumulated in the soil, in a negative feedback to climate change. Little is known about the effective C budget of these new ecosystems and how the presence of different vegetation communities influences CO2 fluxes. On the Matsch glacier forefield (Alps, Italy) we measured over two growing seasons the Net Ecosystem Exchange (NEE) of a typical grassland, dominated by the C3 Festuca halleri All., and a community dominated by the CAM rosettes Sempervivum montanum L. Using transparent and opaque chambers, with air temperature as the driver, we partitioned NEE to calculate Ecosystem Respiration (Reco) and Gross Ecosystem Exchange (GEE). In addition, soil and vegetation samples were collected from the same sites to estimate the Net Ecosystem Carbon Balance (NECB). The two communities showed contrasting GEE but similar Reco patterns, and as a result they were significantly different in NEE during the period measured. The grassland acted as a C sink, with a total cumulated value of -46.4±35.5 g C m-2 NEE, while the plots dominated by the CAM rosettes acted as a source, with 31.9±22.4 g C m-2. In spite of the different NEE, soil analysis did not reveal significant differences in carbon accumulation of the two plant communities (1770±130 for F. halleri and 2080±230 g C m-2 for S. montanum), suggesting that processes often neglected, like lateral flows and winter respiration, can have a similar relevance as NEE in the determination of the Net Ecosystem Carbon Balance.

  20. Colonization of a Deglaciated Moraine: Contrasting Patterns of Carbon Uptake and Release from C3 and CAM Plants

    PubMed Central

    Tagliavini, Massimo; Zerbe, Stefan

    2016-01-01

    Introduction Current glacier retreat makes vast mountain ranges available for vegetation establishment and growth. As a result, carbon (C) is accumulated in the soil, in a negative feedback to climate change. Little is known about the effective C budget of these new ecosystems and how the presence of different vegetation communities influences CO2 fluxes. Methods On the Matsch glacier forefield (Alps, Italy) we measured over two growing seasons the Net Ecosystem Exchange (NEE) of a typical grassland, dominated by the C3 Festuca halleri All., and a community dominated by the CAM rosettes Sempervivum montanum L. Using transparent and opaque chambers, with air temperature as the driver, we partitioned NEE to calculate Ecosystem Respiration (Reco) and Gross Ecosystem Exchange (GEE). In addition, soil and vegetation samples were collected from the same sites to estimate the Net Ecosystem Carbon Balance (NECB). Results The two communities showed contrasting GEE but similar Reco patterns, and as a result they were significantly different in NEE during the period measured. The grassland acted as a C sink, with a total cumulated value of -46.4±35.5 g C m-2 NEE, while the plots dominated by the CAM rosettes acted as a source, with 31.9±22.4 g C m-2. In spite of the different NEE, soil analysis did not reveal significant differences in carbon accumulation of the two plant communities (1770±130 for F. halleri and 2080±230 g C m-2 for S. montanum), suggesting that processes often neglected, like lateral flows and winter respiration, can have a similar relevance as NEE in the determination of the Net Ecosystem Carbon Balance. PMID:28033605

  1. Wall Analyses of Lophocolea Seta Cells (Bryophyta) Before and After Elongation 1

    PubMed Central

    Thomas, Robert J.

    1977-01-01

    Lophocolea heterophylla (Schrad.) Dum. (a leafy liverwort) produces sporophytes with seta cells that elongate 50-fold in 3 to 4 days. Wall components of these cells have been characterized by microscopic histochemistry, colorimetry, and gas chromatography of neutral sugars. Seta cell walls are qualitatively similar to primary cell walls of higher plants. The pectic fraction, however, responds differently to standard histochemical staining and extraction. Quantitatively, mannose, fucose, and rhamnose are in higher percentage, and arabinose and xylose are lower than typically found in vascular plants. Hexuronic acids increase on a percentage basis during elongation; pentoses decrease slightly, while hexose levels remain about the same. Increase in total wall carbohydrate after 2,400% elongation of setae was 1.8-fold. Images PMID:16659846

  2. Behavioral Response of Nothanguina phyllobia to Selected Plant Species

    PubMed Central

    Robinson, A. F.; Orr, C. C.; Abernathy, J. R.

    1979-01-01

    The silver-leaf nightshade nenmtode, Nothanguina phyllobia, is a promising biological control agent for its only reported host, Solanum elaeagnifolium Cav. When infective larvae of N. phyllobia and stem tissue of 39 econmnically important plant species were suspended in 0.5% water agar, nematodes aggregated about S. elaeagnifolium, Solanum carolinense L., Solanum melongena L., Solanum tuberosum L., and Prunus caroliniana (Mill.) Ait. Nematodes responded to Solanum spp. via positive chemotaxis and/or klinokinesis, but aggregated near tissue of P. caroliniana as a result of orthokinetic effects. Nematodes aggregated away from tissue of Hibiscus esculentus L., Triticum aestivum L., Santolina sp., Rosa sp., and Kochia scoparia (L.) Schrad. in the absence of orthokinetic effects. Experiments that excluded light and maintained relative humidity at 100% showed N. phyllobia to ascend the stems of 35 plant species to a height of > 9 cm within 12 h. Differences in stem ascension were not attributable to stem surface characteristics. PMID:19305532

  3. Behavioral Response of Nothanguina phyllobia to Selected Plant Species.

    PubMed

    Robinson, A F; Orr, C C; Abernathy, J R

    1979-01-01

    The silver-leaf nightshade nenmtode, Nothanguina phyllobia, is a promising biological control agent for its only reported host, Solanum elaeagnifolium Cav. When infective larvae of N. phyllobia and stem tissue of 39 econmnically important plant species were suspended in 0.5% water agar, nematodes aggregated about S. elaeagnifolium, Solanum carolinense L., Solanum melongena L., Solanum tuberosum L., and Prunus caroliniana (Mill.) Ait. Nematodes responded to Solanum spp. via positive chemotaxis and/or klinokinesis, but aggregated near tissue of P. caroliniana as a result of orthokinetic effects. Nematodes aggregated away from tissue of Hibiscus esculentus L., Triticum aestivum L., Santolina sp., Rosa sp., and Kochia scoparia (L.) Schrad. in the absence of orthokinetic effects. Experiments that excluded light and maintained relative humidity at 100% showed N. phyllobia to ascend the stems of 35 plant species to a height of > 9 cm within 12 h. Differences in stem ascension were not attributable to stem surface characteristics.

  4. Morpho-histological studies in the aromatic species of Chenopodium from Argentina.

    PubMed

    Bonzani, N E; Barboza, G E; Bugatti, M A; Ariza Espinar, L

    2003-04-01

    A morpho-histological study of the vegetative organs (stem and leaf) of the aromatic species of Chenopodium L. from Argentina [C. ambrosioides L., C. burkartii (Aellen) Vorosch., C. carinatum R. Br., C. chilense Schrad., C. graveolens Willd. var. bangii (Murr) Aellen, C. haumanii Ulbr., C. multifidum L., C. oblanceolatum (Speg.) Giusti, C. pumilio R. Br., C. retusum (Moq.) Moq., and C. venturii (Aellen) Cabrera] was carried out. Classifications for the glandular and non-glandular trichomes are established and their presence among species is presented. A variant in both the dorsiventral and isobilateral mesophyll is reported; some data are valuable for systematic purposes and for the identification of dried and smashed material used as vegetal drug.

  5. Estimation of Ecosystem Parameters of the Community Land Model with DREAM: Evaluation of the Potential for Upscaling Net Ecosystem Exchange

    NASA Astrophysics Data System (ADS)

    Hendricks Franssen, H. J.; Post, H.; Vrugt, J. A.; Fox, A. M.; Baatz, R.; Kumbhar, P.; Vereecken, H.

    2015-12-01

    Estimation of net ecosystem exchange (NEE) by land surface models is strongly affected by uncertain ecosystem parameters and initial conditions. A possible approach is the estimation of plant functional type (PFT) specific parameters for sites with measurement data like NEE and application of the parameters at other sites with the same PFT and no measurements. This upscaling strategy was evaluated in this work for sites in Germany and France. Ecosystem parameters and initial conditions were estimated with NEE-time series of one year length, or a time series of only one season. The DREAM(zs) algorithm was used for the estimation of parameters and initial conditions. DREAM(zs) is not limited to Gaussian distributions and can condition to large time series of measurement data simultaneously. DREAM(zs) was used in combination with the Community Land Model (CLM) v4.5. Parameter estimates were evaluated by model predictions at the same site for an independent verification period. In addition, the parameter estimates were evaluated at other, independent sites situated >500km away with the same PFT. The main conclusions are: i) simulations with estimated parameters reproduced better the NEE measurement data in the verification periods, including the annual NEE-sum (23% improvement), annual NEE-cycle and average diurnal NEE course (error reduction by factor 1,6); ii) estimated parameters based on seasonal NEE-data outperformed estimated parameters based on yearly data; iii) in addition, those seasonal parameters were often also significantly different from their yearly equivalents; iv) estimated parameters were significantly different if initial conditions were estimated together with the parameters. We conclude that estimated PFT-specific parameters improve land surface model predictions significantly at independent verification sites and for independent verification periods so that their potential for upscaling is demonstrated. However, simulation results also indicate

  6. Ecosystem CO2 exchange during the snow-covered season in a boreal peatland, Sweden

    NASA Astrophysics Data System (ADS)

    Zhao, Junbin; Peichl, Matthias; Nilsson, Mats

    2014-05-01

    In high latitude areas, ecosystem CO2 emission in the snow-covered season (SCS) is a crucial part of annual carbon budget, which may account for 33-90% of the summer uptake. As snow pack development is sensitive to the warming climate, the change of CO2 flux in SCS is widely concerned, which, however, is still poorly understood. We used the 12-year CO2 exchange data (2001-2012) from an eddy covariance system in a minerogenic mire in Sweden, where the snow-covered season lasts for about 6 months in a year, to evaluate inter-annual change of CO2 flux in SCS and explore the underlying environmental controllers. Sum of net ecosystem CO2 exchange (NEE) in SCS varied from 8.19 to 32.13 gC m-2 (CO2 release), which accounted for 11-41% of the net CO2 uptake during non-snow-covered period of each year. Over the studied years, the NEE during SCS performed a trend of decline (-1.58 gC m-2 year-1), which was attributed to the decreased daily NEE rather than the variation in the duration of SCS. However, we found no single environmental factor that was responsible for the trend. Over the whole SCS, snow depth did not show direct impact on the day-to-day variation of NEE but acted as an important role in insulating the environment below snow pack from the atmosphere. Daily NEE during the period with a deep snow cover (i.e. snow depth >30cm) was relatively lower and was not affected by air or soil temperature. In contrast, the period with a shallow snow cover (i.e. snow depth < 30cm), which was usually shorter, emitted more CO2 and the NEE was influenced by both air and soil temperatures as well as photosynthetically active radiation. At the end of SCS, snow melt usually lasted for about a month and during this period, NEE was jointly driven by air temperature and photosynthetically active radiation. Given a trend of CO2 emission decline in SCS over 2001-2012 and the influence of temperature on day-to-day NEE variation, our results suggest that winter time CO2 flux is an

  7. Diurnal and Seasonal Variations in the Net Ecosystem CO2 Exchange of a Pasture in the Three-River Source Region of the Qinghai−Tibetan Plateau

    PubMed Central

    Wang, Bin; Jin, Haiyan; Li, Qi; Chen, Dongdong; Zhao, Liang; Tang, Yanhong; Kato, Tomomichi; Gu, Song

    2017-01-01

    Carbon dioxide (CO2) exchange between the atmosphere and grassland ecosystems is very important for the global carbon balance. To assess the CO2 flux and its relationship to environmental factors, the eddy covariance method was used to evaluate the diurnal cycle and seasonal pattern of the net ecosystem CO2 exchange (NEE) of a cultivated pasture in the Three-River Source Region (TRSR) on the Qinghai−Tibetan Plateau from January 1 to December 31, 2008. The diurnal variations in the NEE and ecosystem respiration (Re) during the growing season exhibited single-peak patterns, the maximum and minimum CO2 uptake observed during the noon hours and night; and the maximum and minimum Re took place in the afternoon and early morning, respectively. The minimum hourly NEE rate and the maximum hourly Re rate were −7.89 and 5.03 μmol CO2 m−2 s−1, respectively. The NEE and Re showed clear seasonal variations, with lower values in winter and higher values in the peak growth period. The highest daily values for C uptake and Re were observed on August 12 (−2.91 g C m−2 d−1) and July 28 (5.04 g C m−2 day−1), respectively. The annual total NEE and Re were −140.01 and 403.57 g C m−2 year−1, respectively. The apparent quantum yield (α) was −0.0275 μmol μmol−1 for the entire growing period, and the α values for the pasture’s light response curve varied with the leaf area index (LAI), air temperature (Ta), soil water content (SWC) and vapor pressure deficit (VPD). Piecewise regression results indicated that the optimum Ta and VPD for the daytime NEE were 14.1°C and 0.65 kPa, respectively. The daytime NEE decreased with increasing SWC, and the temperature sensitivity of respiration (Q10) was 3.0 during the growing season, which was controlled by the SWC conditions. Path analysis suggested that the soil temperature at a depth of 5 cm (Tsoil) was the most important environmental factor affecting daily variations in NEE during the growing season, and the

  8. BOREAS TGB-3 Plant Species Composition Data over the NSA Fen

    NASA Technical Reports Server (NTRS)

    Bubier, Jill L.; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor)

    2000-01-01

    The BOReal Ecosystem-Atmosphere Study Trace Gas Biogeochemistry (BOREAS TGB-3) team collected several data sets that contributed to understanding the measured trace gas fluxes over sites in the Northern Study Area (NSA). This data set contains information about the composition of plant species that were within the collars used to measure Net Ecosystem Exchange of CO2 (NEE). The species composition was identified to understand the differences in NEE among the various plant communities in the NSA fen. The data were collected in July of 1994 and 1996. The data are contained in comma-delimited, ASCII files.

  9. Net ecosystem exchange of CO2 with rapidly changing high Arctic landscapes.

    PubMed

    Emmerton, Craig A; St Louis, Vincent L; Humphreys, Elyn R; Gamon, John A; Barker, Joel D; Pastorello, Gilberto Z

    2016-03-01

    High Arctic landscapes are expansive and changing rapidly. However, our understanding of their functional responses and potential to mitigate or enhance anthropogenic climate change is limited by few measurements. We collected eddy covariance measurements to quantify the net ecosystem exchange (NEE) of CO2 with polar semidesert and meadow wetland landscapes at the highest latitude location measured to date (82°N). We coupled these rare data with ground and satellite vegetation production measurements (Normalized Difference Vegetation Index; NDVI) to evaluate the effectiveness of upscaling local to regional NEE. During the growing season, the dry polar semidesert landscape was a near-zero sink of atmospheric CO2 (NEE: -0.3 ± 13.5 g C m(-2) ). A nearby meadow wetland accumulated over 300 times more carbon (NEE: -79.3 ± 20.0 g C m(-2) ) than the polar semidesert landscape, and was similar to meadow wetland NEE at much more southerly latitudes. Polar semidesert NEE was most influenced by moisture, with wetter surface soils resulting in greater soil respiration and CO2 emissions. At the meadow wetland, soil heating enhanced plant growth, which in turn increased CO2 uptake. Our upscaling assessment found that polar semidesert NDVI measured on-site was low (mean: 0.120-0.157) and similar to satellite measurements (mean: 0.155-0.163). However, weak plant growth resulted in poor satellite NDVI-NEE relationships and created challenges for remotely detecting changes in the cycling of carbon on the polar semidesert landscape. The meadow wetland appeared more suitable to assess plant production and NEE via remote sensing; however, high Arctic wetland extent is constrained by topography to small areas that may be difficult to resolve with large satellite pixels. We predict that until summer precipitation and humidity increases enough to offset poor soil moisture retention, climate-related changes to productivity on polar semideserts may be restricted. © 2015 John

  10. Effects of drought - altered seasonality and low rainfall - in net ecosystem carbon exchange of three contrasting Mediterranean ecosystems

    NASA Astrophysics Data System (ADS)

    Pereira, J. S.; Mateus, J. A.; Aires, L. M.; Pita, G.; Pio, C.; Andrade, V.; Banza, J.; David, T. S.; Rodrigues, A.; David, J. S.

    2007-06-01

    Droughts cause reductions in gross primary production (GPP) and also in net ecosystem exchange (NEE), contributing to most of the inter-annual variability in terrestrial carbon sequestration. In seasonally dry climates (Mediterranean) droughts result from reductions in annual rainfall and from changes in rain seasonality. In western Iberia, the hydrological-year (i.e., from October to September) of 2004-2005 was extremely dry, with precipitation 50% below the long-term mean (691 mm in 1961-1990), but 2005-2006 was normal. We compared the carbon fluxes measured by the eddy covariance technique from three contrasting ecosystems in southern Portugal: an evergreen oak woodland (savannah-like) with ca. 21% tree cover; a Mediterranean C3/C4 grassland; and a coppiced eucalyptus plantation. During the dry hydrological-year of 2004-2005, NEE was lowest, the highest sink strength was in the eucalypt plantation (NEE = -399 g C m -2 year-1) as compared to the oak woodland (NEE = -88 g C m -2 year-1), and the grassland (NEE = +49 g C m -2 year -1). The latter was a source of carbon dioxide. The NEE values of the dry year were, however, much lower than those for wetter years, e.g. NEE = -861 g C m-2 year -1 in 2002-2003 in the eucalypt plantation. The NEE of the grassland and the oak savannah in the 2005-2006 hydrological-year, with annual precipitation above the long term mean, were -190 and -120 g C m -2 year-1, respectively. All ecosystems studied increased their rain-use efficiency (GPP per unit of rain volume) increased in dry years. In the case of annual vegetation - grassland and low tree density woodland, however &ndash, rain-use efficiency decreased with severe drought. However, this was more pronounced in the eucalypt plantation due to greater GPP and the use of deep soil water resources. Although both calendar years of 2004 and 2005 had equally low rainfall, the effect of drought on the eucalypt plantation was delayed until the second dry year. This suggests that the

  11. Diurnal and Seasonal Variations in the Net Ecosystem CO2 Exchange of a Pasture in the Three-River Source Region of the Qinghai-Tibetan Plateau.

    PubMed

    Wang, Bin; Jin, Haiyan; Li, Qi; Chen, Dongdong; Zhao, Liang; Tang, Yanhong; Kato, Tomomichi; Gu, Song

    2017-01-01

    Carbon dioxide (CO2) exchange between the atmosphere and grassland ecosystems is very important for the global carbon balance. To assess the CO2 flux and its relationship to environmental factors, the eddy covariance method was used to evaluate the diurnal cycle and seasonal pattern of the net ecosystem CO2 exchange (NEE) of a cultivated pasture in the Three-River Source Region (TRSR) on the Qinghai-Tibetan Plateau from January 1 to December 31, 2008. The diurnal variations in the NEE and ecosystem respiration (Re) during the growing season exhibited single-peak patterns, the maximum and minimum CO2 uptake observed during the noon hours and night; and the maximum and minimum Re took place in the afternoon and early morning, respectively. The minimum hourly NEE rate and the maximum hourly Re rate were -7.89 and 5.03 μmol CO2 m-2 s-1, respectively. The NEE and Re showed clear seasonal variations, with lower values in winter and higher values in the peak growth period. The highest daily values for C uptake and Re were observed on August 12 (-2.91 g C m-2 d-1) and July 28 (5.04 g C m-2 day-1), respectively. The annual total NEE and Re were -140.01 and 403.57 g C m-2 year-1, respectively. The apparent quantum yield (α) was -0.0275 μmol μmol-1 for the entire growing period, and the α values for the pasture's light response curve varied with the leaf area index (LAI), air temperature (Ta), soil water content (SWC) and vapor pressure deficit (VPD). Piecewise regression results indicated that the optimum Ta and VPD for the daytime NEE were 14.1°C and 0.65 kPa, respectively. The daytime NEE decreased with increasing SWC, and the temperature sensitivity of respiration (Q10) was 3.0 during the growing season, which was controlled by the SWC conditions. Path analysis suggested that the soil temperature at a depth of 5 cm (Tsoil) was the most important environmental factor affecting daily variations in NEE during the growing season, and the photosynthetic photon flux

  12. Conceptontwerp nieuwe slaapmatten (Concept Design of Sleeping Mattresses)

    DTIC Science & Technology

    2008-11-01

    gaven geen antwoord op deze vraag. Vraag 13) Is het slaapmatje ooit stuk gegaan tijdens operationeel gebruik? Aantal Ja 25 nee 13 Vraag 14) Hoe...matje stuk is, wordt deze geruild. valt weinig aan te repareren. - Kapot is inleveren en ruilen voor nieuw. Vraag 19) U mag de cijfers 1, 2, 3, 4 en 5...nl.: TNO-rapport | TNO-DV 2008 A486 Bijlage B | 6/9 vraag 14) Is het slaapmatje ooit stuk gegaan tijdens operationeel gebruik? Oja O nee vraag 15

  13. PRESENT; PREScription of Enteral Nutrition in pediaTric Crohn's disease in Spain.

    PubMed

    Navas-López, Victor Manuel; Martín-de-Carpi, Javier; Segarra, Oscar; García-Burriel, José Ignacio; Díaz-Martín, Juan José; Rodríguez, Alejandro; Medina, Enrique; Juste, Mercedes

    2014-03-01

    Objetivos: La nutrición enteral exclusiva (NEE) es una de las estrategias terapéuticas empleadas para inducir la remisión en niños con enfermedad de Crohn (EC). Pese a que la NEE se recomienda en las guías de práctica clínica y en los documentos de consenso, la frecuencia real de su empleo en España es desconocida. Métodos: Encuesta compuesta por 70-items (PRESENT: PREScription of Enteral Nutrition in pediaTric Crohn’s disease in Spain) que se distribuyó a través de la lista de distribución de Sociedad Española de Gastroenterología, Hepatología y Nutrición Pediátrica (SEGHNP). Resultados: Se recibieron los datos de 51 unidades de Gastroenterología Pediátrica del territorio español. De los 287 pacientes recién diagnosticados de EC durante los años 2011-12 en esos centros (139 en 2011 y 148 en 20212), 182 (63%) recibieron NEE (58% en 2011 y 68% en 2012). El 26% de los pacientes que recibieron NEE estaban en recaída. Todos los facultativos que respondieron pensaban que la NEE es efectiva para inducir la remisión clínica en los brotes leves-moderados. El 24,5% no emplean la NEE durante las recaídas. Las formulas enterales empleadas más frecuentemente fueron las específicas para EC (70,6%), la vía oral fue la más utilizada, el 60,8% utilizaron saborizantes y el 9,8% de las unidades permitían un porcentaje variable de calorías en forma de otros alimentos durante el periodo de NEE. El 65% emplearon 5-ASA junto con la NEE, el 69% antibióticos y hasta un 95% inmunomoduladores. La duración de la NEE fue de 8 semanas en el 47,1% de los casos, la transición hacia una dieta normal se realizó de forma secuencial. En relación a las barreras y factores limitantes encontrados por los respondedores para instaurar la NEE destacaban la falta de aceptación por el paciente y/o la familia (71%), falta de tiempo o de personal auxiliar (69%) y la dificultad para convencer al paciente o su familia de la idoneidad del tratamiento (43%). Conclusiones

  14. Inter-annual variability in Alaskan net ecosystem CO2 exchange

    NASA Astrophysics Data System (ADS)

    Luus, Kristina; Lindaas, Jakob; Commane, Roisin; Euskirchen, Eugenie; Oechel, Walter; Zona, Donatella; Chang, Rachel; Kelly, Richard; Miller, Charles; Wofsy, Steven; Lin, John

    2015-04-01

    The high-latitude biospheric carbon cycle's responses to climate change are predicted to have an important role in determining future atmospheric concentrations of CO2. In response to warming soil and air temperatures, Arctic wetlands have been observed to increase rates of both soil C efflux and vegetation C uptake through photosynthesis. However, insights into the regional-scale consequences of these processes for net C uptake have been limited by the large uncertainties existing in process-based model estimates of Arctic net ecosystem CO2 exchange (NEE). The Polar Vegetation Photosynthesis and Respiration Model (PolarVPRM) instead provides data-driven, satellite-based estimates of high-latitude NEE, using a framework which specifically accounts for polar influences on NEE. PolarVPRM calculates NEE as the sum of respiration (R) and gross ecosystem exchange (GEE), where GEE refers to the light-dependent portion of NEE: NEE= -GEE + R. Meteorological inputs for PolarVPRM are provided by the North American Regional Reanalysis (NARR), and land surface inputs are acquired from the Moderate Resolution Imaging Spectroradiometer (MODIS). Growing season R is calculated from air temperature, and subnivean R is calculated according to soil temperature. GEE is calculated according to shortwave radiation, air temperature, and MODIS-derived estimates of soil moisture and vegetation biomass. Previously, model validation has indicated that PolarVPRM showed reasonably good agreement with eddy covariance observations at nine North American Arctic sites, of which three were used for calibration purposes. For this project, PolarVPRM NEE was calculated year-round across Alaska at a three-hourly temporal resolution and a spatial resolution of 1 6°×1 4° (latitude × longitude). The objective of this work was to gain insight into inter-annual variability in Alaskan NEE, R and GEE, and an understanding of which meteorological and land surface drivers account for these observed patterns

  15. Interactive state-parameter estimation of a crop carbon mass balance model through the assimilation of observed winter wheat carbon flux and stock data

    NASA Astrophysics Data System (ADS)

    Sus, O.; Williams, M. D.; Gruenwald, T.

    2010-12-01

    Next to the consideration of land management practises, modelling the carbon balance of croplands requires a crop carbon budget model that realistically simulates photosynthesis, ecosystem respiration, soil carbon dynamics, and phenology dependant on crop-specific parameters and carbon allocation patterns. A crop carbon mass balance model is a tool which can aid to answer questions related to cropland carbon sequestration potential, best-practise recommendations, seasonal patterns and amplitude of net carbon exchange (NEE), and prediction of biomass growth and crop yield. However, land management complicates modelling of cropland NEE by largely determining the onset and length of the growing season of agricultural areas. Human decision making on crop cultivars, sowing and harvest dates, and management practices is difficult to simulate, and corresponding reliable data for larger spatial and temporal scales is still sparse. Crop carbon budget models require a specific set of parameters, some of which are poorly understood and are thus of empirical rather than mechanistic nature. Here, we present a study that deals with the assimilation of observations of both carbon flux and stock data into a crop C budget model (SPAc). Our data assimilation procedure (the Ensemble Kalman Filter, EnKF) aims at updating both model states and parameters, so that we will gain insight into optimized parameter values and carbon stock/flux estimates within quantified confidence limits. We obtained measured data of NEE, LAI, and leaf, root, stem, and storage organ dry mass for a winter wheat season in 2005/2006 from the CarboEurope Fluxnet site at Klingenberg/Germany. We conducted several model experiments, for each of which we assimilated a unique combination of data sources. We find that the assimilation of NEE data leads to reduced model error (observed vs. modelled NEE) compared to a model run without data assimilation (a reduction of ~15-20% of RMSE). The assimilated dry mass data on

  16. Detecting management and fertilization effects on the carbon balance of winter oilseed rape with manual closed chamber measurements: Can we outrange gap-filling uncertainty and spatiotemporal variability?

    NASA Astrophysics Data System (ADS)

    Huth, Vytas; Moffat, Antje Maria; Calmet, Anna; Andres, Monique; Laufer, Judit; Pehle, Natalia; Rach, Bernd; Gundlach, Laura; Augustin, Jürgen

    2017-04-01

    Winter oilseed rape is the dominant biofuel crop in the young moraine landscape in North-Eastern Germany. However, studies on the effect of rapeseed cropping on net ecosystem exchange of CO2 (NEE) and the soil carbon (SC) balance are scarce. SC balance estimates are usually derived from long-term soil sampling field trials where rapeseed is part of different crop rotations. The estimated annual differences linked to rapeseed cropping are rather small (varying between losses of 40 g C m-2 and gains of up to 100 g C m-2). Testing management effects on the NEE and SC balance of cropping systems is best done by comparing plots with different treatments at the same site under the same climate. The soil sampling approach is in the need of field trials that run over decades, which has the disadvantage that management strategies of practical farming may have already changed when the results are derived. Continuous eddy covariance measurements of NEE would require large fields in flat terrain for each of the treatments, which is especially complicated in the heterogeneous landscapes of glacigenic origin of North-Eastern Germany. The common approach of using the chamber technique to derive NEE, however, is subject to the local soil and plant stand heterogeneities due to its tiny footprint. This technique might also disturb the ecosystem, the measurements are usually discontinuous requiring elaborate gap-filling techniques, and it has mostly been used on organic soils where large respiratory C losses occur. Therefore, our aim was to answer, if a combined approach of the eddy covariance and the chamber technique can detect the relatively small NEE and SC differences of rapeseed cropping on mineral soils within a shorter period of time than conventional soil sampling field trials can. We tested the new experimental design taking the advantages of both techniques into account: The eddy covariance tower measuring the NEE dynamics during the year; the chamber measurements to

  17. Stimulation of Mojave Desert net ecosystem CO2 uptake after winter precipitation with the opposite effect after summer rains based on 7 years of flux data

    NASA Astrophysics Data System (ADS)

    Jasoni, Richard; Arnone, John; Fenstermaker, Lynn; Wohlfahrt, Georg

    2014-05-01

    Eddy covariance measurements of net ecosystem CO2 exchange (NEE) in the Mojave Desert (Jasoni et al. 2005-Global Change Biology 11:749-756; Wohlfahrt et al. 2008-Global Change Biology 14:1475-1487), and in other deserts of the world (e.g., Hastings et al. 2005- Global Change Biology 14:927-939, indicate greater rates of net CO2 uptake (more negative NEE values) and net ecosystem productivity (NEP) than would have been expected for deserts (as high as -120 g C m-2 year-1). We continue to observe high rates of NEE and NEP and seek explanations for these findings at interannual, seasonal, and sub-seasonal time scales. Because moisture availability most strongly constrains biological activity in deserts, responses to rains probably play a significant role in defining components of NEE-namely net primary productivity (NPP, or roughly net photosynthesis by vascular and non-vascular plants) and heterotrophic respiration (Rh, mainly by soil microorganisms). Most precipitation in the Mojave Desert falls from October through April and periodically in the summer as convective storms. The main objective of this study was to quantify the extent to which NEE and the net flux of CO2 from/to biological soil crust (BSC) covered soil surfaces respond to rain pulses occurring during cool/cold and warm/hot times of the year. Flux data from 7 years (2005-2011) of measurements at our shub land desert site (average 150 mm rain per year) located 120 km northwest of Las Vegas showed a range in NEP from -111±34 to -47±28 g C m-2 year-1. Cool season rains usually stimulated NEE (more negative NEE values or net CO2 uptake) while warm season rains reversed this effect and led to positive NEE values (net ecosystem CO2 efflux. Cool season stimulation of NEE often occurred in the absence of green leaves on vascular plants, suggesting that photosynthesis of BSCs (up to 70% of soil surface covered by cyanobacteria, mosses, and lichens) were responsible for this net uptake. At other times during

  18. Indigenous Educational Models for Contemporary Practice: In Our Mother's Voice. Sociocultural, Political, and Historical Studies in Education.

    ERIC Educational Resources Information Center

    Nee-Benham, Maenette Kape'ahiokalani Padeken Ah, Ed.

    This book presents a collection of papers on the rights of indigenous students to an equal education. The 15 chapters include: (1) "Gathering Together To Travel to the Source: A Vision for a Language and Culture-Based Educational Model" (Maenette Kape'ahiokalani Padeken Ah Nee-Benham and Joanne Elizabeth Cooper); (2) "Building a Child-Centered…

  19. The EV-1 airborne microwave observatory of subcanopy and subsurface (AirMOSS) investigation

    USDA-ARS?s Scientific Manuscript database

    AirMOSS is one of the five Earth Venture-1 investigations selected in May 2010, with the goal of improving the estimates of the North American net ecosystem exchange (NEE) through high-resolution observations of root zone soil moisture (RZSM). The 5-year AirMOSS investigation is deigned to overlap w...

  20. Large interannual variability in net ecosystem carbon dioxide exchange of a disturbed temperate peatland.

    PubMed

    Aslan-Sungur, Guler; Lee, Xuhui; Evrendilek, Fatih; Karakaya, Nusret

    2016-06-01

    Peatland ecosystems play an important role in the global carbon (C) cycle as significant C sinks. However, human-induced disturbances can turn these sinks into sources of atmospheric CO2. Long-term measurements are needed to understand seasonal and interannual variability of net ecosystem CO2 exchange (NEE) and effects of hydrological conditions and their disturbances on C fluxes. Continuous eddy-covariance measurements of NEE were conducted between August 2010 and April 2014 at Yenicaga temperate peatland (Turkey), which was drained for agricultural usage and for peat mining until 2009. Annual NEE during the three full years of measurement indicated that the peatland acted as a CO2 source with large interannual variability, at rates of 246, 244 and 663 g Cm(-2)yr(-1) for 2011, 2012, and 2013 respectively, except for June 2011, and May to July 2012. The emission strengths were comparable to those found for severely disturbed tropical peatlands. The peak CO2 emissions occurred in the dry summer of 2013 when water table level (WTL) was below a threshold value of -60 cm and soil water content (SCW) below a threshold value of 70% by volume. Water availability index was found to have a stronger explanatory power for variations in monthly ecosystem respiration (ER) than the traditional water status indicators (SCW and WTL). Air temperature, evapotranspiration and vapor pressure deficient were the most significant variables strongly correlated with NEE and its component fluxes of gross primary production and ER.

  1. Addressable nanoelectrode membrane arrays: fabrication and steady-state behavior.

    PubMed

    Zoski, Cynthia G; Yang, Nianjun; He, Peixin; Berdondini, Luca; Koudelka-Hep, Milena

    2007-02-15

    An addressable nanoelectrode membrane array (ANEMA) based on a Au-filled track-etched polycarbonate membrane was fabricated. The Au-filled membrane was secured to a lithographically fabricated addressable ultramicroelectrode (UME) array patterned with 25 regularly spaced (100 microm center to center spacing), 10 microm diameter recessed Pt UMEs to create 25 microregions of 10 microm diameter nanoelectrode ensembles (NEEs) on the membrane. The steady-state voltammetric behavior of 1.0 mM Ru(NH(3))(6)Cl(3) and 1.0 mM ferrocene methanol in 0.1 M KCl on each of the micro NEEs resulted in sigmoidal-shaped voltammograms which were reproducible across the ANEMA. This reproducibility of the steady-state current was attributed to the overlapping hemispherical diffusion layers at the Au-filled nanopores of each 10 microm diameter NEE of a ANEMA. The track-etched polycarbonate membranes were filled using a gold electroless deposition procedure into the 30 nm diameter pores in the membrane. Electrical connection between the Au-filled template array and the lithographic UME platform array was achieved by potentiostatic electrodeposition of Cu from an acidic copper solution into each of the 25 recessed Pt UMEs on the UME array platform. A multiplexer unit capable of addressing 64 individual micro NEEs on an ANEMA is described. ANEMAs have advantages of high reproducibility, facile fabrication, multitime reuse of lithographically fabricated UME arrays, and purely steady-state behavior.

  2. Effects of alpha adrenoceptor blockade on renal nerve stimulation-induced norepinephrine release and vasoconstriction in the dog kidney.

    PubMed

    Hisa, H; Araki, S; Tomura, Y; Hayashi, Y; Satoh, S

    1989-02-01

    Effects of alpha-antagonists on renal norepinephrine (NE) release and vasoconstriction induced by renal nerve stimulation (RNS) were examined in pentobarbital-anesthetized dogs. RNS at 1,2 and 3 Hz (1 msec duration, 10-20 V) for 1 min decreased renal blood flow (RBF) and increased both the renal venous NE concentration (NEC) and calculated renal NE efflux (NEE). The RBF responses to 2 and 3 Hz RNS and NEC responses to 1, 2 and 3 Hz RNS during intrarenal arterial infusion of yohimbine (1.0 micrograms/kg/min) were greater than those observed during the control period. The NEE responses to 1 and 2 Hz RNS, but not to 3 Hz RNS, were also potentiated by the yohimbine infusion. Prazosin treatment (0.2 mg/kg i.v.) attenuated the RBF responses. Subsequent infusion of yohimbine potentiated both the NEC and NEE responses to 1, 2 and 3 Hz RNS in this alpha-1 adrenoceptor-blocked state. These results suggest that an alpha-2 adrenoceptor-mediated inhibitory mechanism of neural NE release exists in the dog kidney, which can be activated by endogenously released catecholamines to modulate the neural control of renal hemodynamics. Alpha-1 adrenoceptor-mediated renal vasoconstriction may affect the evaluation of neural NE release by NEE when high-frequency RNS is applied during inhibition of the alpha-2 adrenoceptor-mediated mechanism.

  3. New bactericide derived from Isatin for treating oilfield reinjection water

    PubMed Central

    2012-01-01

    Isatin, an extract from Strobilanthes cusia (Nees) Kuntze, was the base for synthesizing derivatives that were screened for antibacterial activity against oilfield water-borne bacteria. The bacterial groups are sulfate reducing, iron and total. The derivatives were characterized by spectrums and they showed good to moderate activity against sulfate reducing bacteria. PMID:22929650

  4. Nutritional Needs

    USDA-ARS?s Scientific Manuscript database

    The dramatic growth of infants during the 1st yr of life (a 3-fold increase in weight; a 50% increase in length) and continued growth, albeit at lower rates, from 1 yr of age through adolescence impose unique nutritional needs. The needs for growth are superimposed on relatively high maintenance nee...

  5. 76 FR 11821 - Submission for OMB Review; Comment Request Survey of Principal Investigators on Earthquake...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-03

    ... Submission for OMB Review; Comment Request Survey of Principal Investigators on Earthquake Engineering... Investigators on Earthquake Engineering Research Awards Made by the National Science Foundation, 2003-2009. Type... George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES). The purpose of the proposed...

  6. Carbon dioxide and water vapor exchange in a warm temperate grassland

    Treesearch

    K.A. Novick; P.C. Stoy; G.G. Katul; D.S. Ellsworth; M.B.S. Siqueira; J. Juang; R. Oren

    2004-01-01

    Grasslands cover about 40% of the ice-free global terrestrial surface, but their contribution to local and regional water and carbon fluxes and sensitivity to climatic perturbations such as drought remains uncertain. Here, we assess the direction and magnitude of net ecosystem carbon exchange (NEE) and it components, ecosystem carbon assimilation (Ac...

  7. ELEVATED CO2 AND TEMPERATURE ALTER THE ECOSYSTEM C EXCHANGE IN A YOUNG DOUGLAS FIR MESOCOSM EXPERIMENT

    EPA Science Inventory

    We investigated the effects of elevated CO2 (EC) [ambient CO2 (AC) + 190 ppm] and elevated temperature (ET) [ambient temperature (AT) + 3.6 °C] on net ecosystem exchange (NEE) of seedling Douglas fir (Pseudotsuga menziesii) mesocosms. As the study utilized seedlings in reconstruc...

  8. Mass timber rocking panel retrofit of a four-story soft-story building with full-scale shake table validation

    Treesearch

    Pouria Bahmani; John van de Lindt; Asif Iqbal; Douglas Rammer

    2017-01-01

    Soft-story wood-frame buildings have been recognized as a disaster preparedness problem for decades. There are tens of thousands of these multi-family three- and four-story structures throughout California and the United States. The majority were constructed between 1920 and 1970, with many being prevalent in the San Francisco Bay Area in California. The NEES Soft...

  9. Analysis of isotopic labeling in peptide fragments by tandem mass spectrometry

    USDA-ARS?s Scientific Manuscript database

    The cellular phenotype is the consequence of dynamic metabolic events that occur in a spacially dependent fashion. This spatial and temporal complexity presents challenges for investigating primary metabolism and improved methods to probe biochemical events such as amino acid biosynthesis may be nee...

  10. Implementing Strategic Management of Producibility in Military Hardware Design

    DTIC Science & Technology

    1985-05-01

    production life. Maximum producibility can not be reached unless it is nee Figura 5 considered prior to commencing production. The cost savings...from your publica ion will be greatfully acknowledged in my thesis and any possible follow on journal articles or presentations. Si ncer’el y. -12

  11. First report of laurel wilt, caused by Raffaelea lauricola , on Sassafras ( Sassafras albidum ) in Arkansas

    Treesearch

    Rabiu Olatinwo; C. Barton; Stephen Fraedrich; W. Johnson; J. Hwang

    2016-01-01

    Laurel wilt, caused by Raffaelea lauricola T.C. Harrin., Aghayeva & Fraedrich, is a lethal disease that affects members of the laurel family (Lauraceae) including avocado (Persea americana Mill), redbay (Persea borbonia [L.] Spreng., Nees), and sassafras (Sassafras albidum [Nutt.]). The fungus is a symbiont of an exotic ambrosia beetle (Xyleborus glabratus...

  12. Do plant population and planting date make a difference in corn production?

    USDA-ARS?s Scientific Manuscript database

    One management practice that can positively or negatively impact corn yield is plant population. Yield potential can also be influenced by the date of planting, which is strongly linked to the at-planting and in-season weather and climatic conditions. Even when considering management changes, we nee...

  13. Women in History--Mary Seacole

    ERIC Educational Resources Information Center

    Harmer, Bonnie

    2005-01-01

    Born in Jamaica in 1805, Mary Seacole (nee Grant), was the daughter of a Black Creole boarding house owner and a Scottish Army officer. Like many Creole doctress women, Seacole was taught African herbal medicine arts from her mother. In addition to understanding traditional herbal medicine, she gleaned an understanding of Western medicine from the…

  14. MaizeGDB: everything old is new again! [abstract

    USDA-ARS?s Scientific Manuscript database

    The focus of genetic, genomic, and breeding research evolves over time, making it necessary to continually redefine the paradigm for data access and data analysis tools. Here we report the reinvention of MaizeGDB, the maize genetics and genomics database, to meet maize researchers’ ever changing nee...

  15. Trichotillomania (Hair-Pulling Disorder)

    MedlinePlus

    Trichotillomania (hair-pulling disorder) Overview Trichotillomania (trik-o-til-o-MAY-nee-uh), also called hair-pulling disorder, is a mental disorder that involves recurrent, irresistible urges to pull out hair from your scalp, eyebrows or other areas of ...

  16. Modeling Net Ecosystem Carbon Exchange of Alpine Grasslands with a Satellite-Driven Model

    PubMed Central

    Zhao, Yuping; Zhang, Xianzhou; Fan, Yuzhi; Shi, Peili; He, Yongtao; Yu, Guirui; Li, Yingnian

    2015-01-01

    Estimate of net ecosystem carbon exchange (NEE) between the atmosphere and terrestrial ecosystems, the balance of gross primary productivity (GPP) and ecosystem respiration (Reco) has significant importance for studying the regional and global carbon cycles. Using models driven by satellite data and climatic data is a promising approach to estimate NEE at regional scales. For this purpose, we proposed a semi-empirical model to estimate NEE in this study. In our model, the component GPP was estimated with a light response curve of a rectangular hyperbola. The component Reco was estimated with an exponential function of soil temperature. To test the feasibility of applying our model at regional scales, the temporal variations in the model parameters derived from NEE observations in an alpine grassland ecosystem on Tibetan Plateau were investigated. The results indicated that all the inverted parameters exhibit apparent seasonality, which is in accordance with air temperature and canopy phenology. In addition, all the parameters have significant correlations with the remote sensed vegetation indexes or environment temperature. With parameters estimated with these correlations, the model illustrated fair accuracy both in the validation years and at another alpine grassland ecosystem on Tibetan Plateau. Our results also indicated that the model prediction was less accurate in drought years, implying that soil moisture is an important factor affecting the model performance. Incorporating soil water content into the model would be a critical step for the improvement of the model. PMID:25849325

  17. Quantum Cascade Lasers

    DTIC Science & Technology

    2007-11-02

    predicted small linewidth enhancement factor of QC lasers was measured in outside collaboration ( Prof . Shun-Lien Chuang at UIUC) and confirmed to be...Gmachl, Michael C. Wanke, Federico Capasso, Albert L. Hutchinson, Deborah L. Sivco, Sung- Nee G. Chu, and Alfred Y. Cho “Surface plasmon quantum cascade

  18. Estimating Pan Arctic Net Ecosystem Exchange using Functional Relationships with Air temperature, Leaf Area Index and Photosynthetic Active Radiation

    NASA Astrophysics Data System (ADS)

    Mbufong, H.; Kusbach, A.; Lund, M.; Persson, A.; Christensen, T. R.; Tamstorf, M. P.; Connolly, J.

    2015-12-01

    The high variability in Arctic tundra net ecosystem exchange (NEE) of carbon (C) is often attributed to the high spatial heterogeneity of Arctic tundra. Current models of carbon exchange thus handle the Arctic as either a single or few ecosystems, responding to environmental change in the same manner. In this study, we developed and tested a simple NEE model using the Misterlich light response curve (LRC) function with photosynthetic photon flux density (PPFD) as the main driving variable. Model calibration was carried out with eddy covariance carbon dioxide data from 12 Arctic tundra sites. The model input parameters (fcsat, Rd and α) were estimated as a function of air temperature and leaf area index (LAI) and represent specific characteristics of the NEE-PPFD relationship. They describe the saturation flux, dark respiration and initial light use efficiency, respectively. While remotely sensed LAI is readily available as a MODIS Terra product (MCD15A3), air temperature was estimated from a direct relationship with MODIS land surface temperature (MOD11A2, LST). Therefore, no specific knowledge of the vegetation type is required. Preliminary results show the model captures the spatial heterogeneity of the Arctic tundra but so far, overestimates NEE on all 17 test sites which include heaths, bogs, fens, and tussock tundra vegetation. The final updated results and error assessment will be presented at the conference in December.

  19. Indicators and Methods for Constructing a U.S. Human Well-being Index (HWBI) for Ecosystem Services Research

    EPA Science Inventory

    Humans are dependent upon the services provided by nature, and unless we effectively account for the range of values from ecosystems in our efforts to protect the environment, we cannot sustain human well-being. In light of this dependence, a national measure of well-being is nee...

  20. Comparing simple respiration models for eddy flux and dynamic chamber data

    Treesearch

    Andrew D. Richardson; Bobby H. Braswell; David Y. Hollinger; Prabir Burman; Eric A. Davidson; Robert S. Evans; Lawrence B. Flanagan; J. William Munger; Kathleen Savage; Shawn P. Urbanski; Steven C. Wofsy

    2006-01-01

    Selection of an appropriate model for respiration (R) is important for accurate gap-filling of CO2 flux data, and for partitioning measurements of net ecosystem exchange (NEE) to respiration and gross ecosystem exchange (GEE). Using cross-validation methods and a version of Akaike's Information Criterion (AIC), we evaluate a wide range of...

  1. Progestogens to Prevent Preterm Birth: A Review of the Research about Progestogens for Women at Risk

    MedlinePlus

    Progestogens To Prevent Preterm Birth A Review of the Research About Progestogens for Women at Risk Is This Information Right for Me? Yes, if: At ... is called “spontaneous (spon-TAY-nee-us) preterm birth.” An example is if your “water broke” before ...

  2. CARBON FLUXES ON NORTH AMERICAN RANGELANDS

    USDA-ARS?s Scientific Manuscript database

    Seasonal patterns of growth and thus carbon uptake are relevant to both scientists who study ecosystem properties and managers who strive to maintain rangeland productivity. We studied seasonal patterns of net ecosystem exchange of carbon (NEE) on 11 US rangelands over a 6-year period. All sites w...

  3. ELEVATED CO2 AND TEMPERATURE ALTER THE ECOSYSTEM C EXCHANGE IN A YOUNG DOUGLAS FIR MESOCOSM EXPERIMENT

    EPA Science Inventory

    We investigated the effects of elevated CO2 (EC) [ambient CO2 (AC) + 190 ppm] and elevated temperature (ET) [ambient temperature (AT) + 3.6 °C] on net ecosystem exchange (NEE) of seedling Douglas fir (Pseudotsuga menziesii) mesocosms. As the study utilized seedlings in reconstruc...

  4. Estimating photosynthetic 13C discrimination in terrestrial CO2 exchange from canopy to regional scales.

    Treesearch

    Chun-Ta Lai; James R. Ehleringer; Pieter Tans; Steven C. Wofsy; Shawn P. Urbanski; David Y. Hollinger

    2004-01-01

    We determined δ13C values associated with canopy gross and net C02 fluxes from four U.S. sites sampled between 2001 and 2002. Annual mean, flux-weighted δ13C values of net ecosystem C02 exchange (NEE) were estimated for four contrasting ecosystems (three...

  5. Evaluation of Growing Season Milestones, Using Eddy Covariance Time-Series of Net Ecosystem Exchange

    NASA Astrophysics Data System (ADS)

    Pastorello, G.; Faybishenko, B.; Poindexter, C.; Menzer, O.; Agarwal, D.; Papale, D.; Baldocchi, D. D.

    2014-12-01

    Common methods for determining timing of plants' developmental events, such as direct observation and remote sensing of NDVI, usually produce data of temporal resolution on the order of one week or more. This limitation can make observing subtle trends across years difficult. The goal of this presentation is to demonstrate a conceptual approach and a computational technique to quantify seasonal, annual and long-term phenological indices and patterns, based on continuous eddy covariance measurements of net ecosystem exchange (NEE) measured at eddy covariance towers in the AmeriFlux network. Using a comprehensive time series analysis of NEE fluxes in different climatic zones, we determined multiple characteristics (and their confidence intervals) of the growing season including: the initiation day—the day when canopy photosynthesis development starts, the photosynthesis stabilization day - the day when the development process of canopy photosynthesis starts to slow down and gradually moves toward stabilization, and the growing season effective termination day. We also determined the spring photosynthetic development velocity and the fall photosynthetic development velocity. The results of calculations using NEE were compared with those from temperature and precipitation data measured at the same AmeriFlux tower stations, as well as with the in-situ directly observed phenological records. The results of calculations of phenological indices from the NEE time-series collected at AmeriFlux sites can be used to constrain the application of other time- and labor-intensive sensing methods and to reduce the uncertainty in identifying trends in the timing of phenological indices.

  6. Carbon isotope ratios document that the elytra of western corn rootworm reflects adult versus larval feeding and later instar larvae prefer Bt corn to alternate hosts

    USDA-ARS?s Scientific Manuscript database

    The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is a major pest of maize, Zea mays L., worldwide. While exploring conventional approaches to management and more recently bioengineering, extended research has been conducted on ways to manage its root-feeding larvae. The nee...

  7. Net ecosystem CO2 exchange of a primary tropical peat swamp forest in Sarawak, Malaysia

    NASA Astrophysics Data System (ADS)

    Tang Che Ing, A.; Stoy, P. C.; Melling, L.

    2014-12-01

    Tropical peat swamp forests are widely recognized as one of the world's most efficient ecosystems for the sequestration and storage of carbon through both their aboveground biomass and underlying thick deposits of peat. As the peat characteristics exhibit high spatial and temporal variability as well as the structural and functional complexity of forests, tropical peat ecosystems can act naturally as both carbon sinks and sources over their life cycles. Nonetheless, few reports of studies on the ecosystem-scale CO2 exchange of tropical peat swamp forests are available to-date and their present roles in the global carbon cycle remain uncertain. To quantify CO2 exchange and unravel the prevailing factors and potential underlying mechanism regulating net CO2 fluxes, an eddy covariance tower was erected in a tropical peat swamp forest in Sarawak, Malaysia. We observed that the diurnal and seasonal patterns of net ecosystem CO2 exchange (NEE) and its components (gross primary productivity (GPP) and ecosystem respiration (RE)) varied between seasons and years. Rates of NEE declined in the wet season relative to the dry season. Conversely, both the gross primary productivity (GPP) and ecosystem respiration (RE) were found to be higher during the wet season than the dry season, in which GPP was strongly negatively correlated with NEE. The average annual NEE was 385 ± 74 g C m-2 yr-1, indicating the primary peat swamp forest functioned as net source of CO2 to the atmosphere over the observation period.

  8. Estimating parameters of a forest ecosystem C model with measurements of stocks and fluxes as joint constraints

    Treesearch

    Andrew D. Richardson; Mathew Williams; David Y. Hollinger; David J.P. Moore; D. Bryan Dail; Eric A. Davidson; Neal A. Scott; Robert S. Evans; Holly. Hughes

    2010-01-01

    We conducted an inverse modeling analysis, using a variety of data streams (tower-based eddy covariance measurements of net ecosystem exchange, NEE, of CO2, chamber-based measurements of soil respiration, and ancillary ecological measurements of leaf area index, litterfall, and woody biomass increment) to estimate parameters and initial carbon (C...

  9. Role of Neurotensin in Radiation-Induced Hypothermia in Rats

    DTIC Science & Technology

    1991-01-01

    or in the prew-nee of 100 ng ignfctlicraeaungheeeseohsame (0). 300 nig ().•) or 5W0 nig (0) DSCG . Each point re•ets the mean ± SE from mast cells...ofdsodium cromoglycate B. M. PATERSON. and H. J. WELCH. Neur. ternsin stimulates exocyto- ( DSCG ) and antihistamines on postirradiation cereomal blood flow

  10. Compensatory water effects link yearly global land CO2 sink changes to temperature

    NASA Astrophysics Data System (ADS)

    Jung, Martin; Reichstein, Markus; Schwalm, Christopher R.; Huntingford, Chris; Sitch, Stephen; Ahlström, Anders; Arneth, Almut; Camps-Valls, Gustau; Ciais, Philippe; Friedlingstein, Pierre; Gans, Fabian; Ichii, Kazuhito; Jain, Atul K.; Kato, Etsushi; Papale, Dario; Poulter, Ben; Raduly, Botond; Rödenbeck, Christian; Tramontana, Gianluca; Viovy, Nicolas; Wang, Ying-Ping; Weber, Ulrich; Zaehle, Sönke; Zeng, Ning

    2017-01-01

    Large interannual variations in the measured growth rate of atmospheric carbon dioxide (CO2) originate primarily from fluctuations in carbon uptake by land ecosystems. It remains uncertain, however, to what extent temperature and water availability control the carbon balance of land ecosystems across spatial and temporal scales. Here we use empirical models based on eddy covariance data and process-based models to investigate the effect of changes in temperature and water availability on gross primary productivity (GPP), terrestrial ecosystem respiration (TER) and net ecosystem exchange (NEE) at local and global scales. We find that water availability is the dominant driver of the local interannual variability in GPP and TER. To a lesser extent this is true also for NEE at the local scale, but when integrated globally, temporal NEE variability is mostly driven by temperature fluctuations. We suggest that this apparent paradox can be explained by two compensatory water effects. Temporal water-driven GPP and TER variations compensate locally, dampening water-driven NEE variability. Spatial water availability anomalies also compensate, leaving a dominant temperature signal in the year-to-year fluctuations of the land carbon sink. These findings help to reconcile seemingly contradictory reports regarding the importance of temperature and water in controlling the interannual variability of the terrestrial carbon balance. Our study indicates that spatial climate covariation drives the global carbon cycle response.

  11. Linda S. Gottfredson

    ERIC Educational Resources Information Center

    Wainer, Howard; Robinson, Daniel H.

    2009-01-01

    This article presents an interview with Linda Gottfredson (nee Howarth), who obtained her BA (psychology, Phi Beta Kappa) from UC Berkeley in 1969, served in the Peace Corps in the Malaysian Health Service from 1969 to 1972, and received her PhD (sociology) from Johns Hopkins University (JHU) in 1976. She was Research Scientist at JHU's Center for…

  12. Satellite-based modeling of gross primary production in an evergreen needleleaf forest

    Treesearch

    Xiangming Xiao; David Hollinger; John Aber; Mike Goltz; Eric A. Davidson; Qingyuan Zhang; Berrien Moore III

    2004-01-01

    The eddy covariance technique provides valuable information on net ecosystem exchange (NEE) of CO2, between the atmosphere and terrestrial ecosystems, ecosystem respiration, and gross primary production (GPP) at a variety of C02 eddy flux tower sites. In this paper, we develop a new, satellite-based Vegetation Photosynthesis Model (VPM) to estimate the seasonal dynamcs...

  13. Estimation of net ecosystem carbon exchange for the conterminous United States by combining MODIS and AmeriFlux data

    Treesearch

    Jingfeng Xiao; Qianlai Zhuang; Dennis D. Baldocchi; Beverly E. Law; Andrew D. Richardson; Jiquan Chen; Ram Oren; Gegory Starr; Asko Noormets; Siyan Ma; Sashi B. Verma; Sonia Wharton; Steven C. Wofsy; Paul V. Bolstad; Sean P. Burns; David R. Cook; Peter S. Curtis; Bert G. Drake; Matthias Falk; MArc L. Fischer; David R. Foster; Lianhong Gu; Julian L. Hadley; David Y. Hollinger; Gabriel G. Katul; Marcy Litvak; Timothy Martin; Roser Matamala; Steve McNulty; Tilden P. Meyers; Russell K. Monson; J. William Munger; Walter C. Oechel; Kyaw Tha Paw U; Hans Peter Schmid; Russell L. Scott; Ge Sun; Andrew E. Suyker; Margaret S. Torn

    2008-01-01

    Eddy covariance flux towers provide continuous measurements of net ecosystem carbon exchange (NEE) for a wide range of climate and biome types. However, these measurements only represent the carbon fluxes at the scale of the tower footprint. To quantify the net exchange of carbon dioxide between the terrestrial biosphere and the atmosphere for regions or continents,...

  14. Nanoelectrode ensembles as recognition platform for electrochemical immunosensors.

    PubMed

    Mucelli, S Pozzi; Zamuner, M; Tormen, M; Stanta, G; Ugo, P

    2008-07-15

    In this study we demonstrate the possibility to prepare highly sensitive nanostructured electrochemical immunosensors by immobilizing biorecognition elements on nanoelectrode ensembles (NEEs) prepared in track-etch polycarbonate membranes. The gold nanodisk electrodes act as electrochemical transducers while the surrounding polycarbonate binds the antibody-based biorecognition layer. The interaction between target protein and antibody is detected by suitable secondary antibodies labelled with a redox enzyme. A redox mediator, added to the sample solution, shuttles electrons from the nanoelectrodes to the biorecognition layer, so generating an electrocatalytic signal. This allows one to fully exploit the highly improved signal-to-background current ratio, typical of NEEs. In particular, the receptor protein HER2 was studied as the target analyte. HER2 detection allows the identification of breast cancer that can be treated with the monoclonal antibody trastuzumab. NEEs were functionalized with trastuzumab which interacts specifically with HER2. The biorecognition process was completed by adding a primary antibody and a secondary antibody labelled with horseradish peroxidase. Hydrogen peroxide was added to modulate the label electroactivity; methylene blue was the redox mediator generating voltammetric signals. NEEs functionalized with trastuzumab were tested to detect small amounts of HER2 in diluted cell lysates and tumour lysates.

  15. FACILITATING ADVANCED URBAN METEOROLOGY AND AIR QUALITY MODELING CAPABILITIES WITH HIGH RESOLUTION URBAN DATABASE AND ACCESS PORTAL TOOLS

    EPA Science Inventory

    Information of urban morphological features at high resolution is needed to properly model and characterize the meteorological and air quality fields in urban areas. We describe a new project called National Urban Database with Access Portal Tool, (NUDAPT) that addresses this nee...

  16. Women in History--Mary Seacole

    ERIC Educational Resources Information Center

    Harmer, Bonnie

    2005-01-01

    Born in Jamaica in 1805, Mary Seacole (nee Grant), was the daughter of a Black Creole boarding house owner and a Scottish Army officer. Like many Creole doctress women, Seacole was taught African herbal medicine arts from her mother. In addition to understanding traditional herbal medicine, she gleaned an understanding of Western medicine from the…

  17. Peritoneal Dialysis

    MedlinePlus

    Peritoneal dialysis Overview By Mayo Clinic Staff Peritoneal dialysis (per-ih-toe-NEE-ul die-AL-uh-sis) is a way to remove waste products from your blood when your kidneys can no longer do the job adequately. A cleansing fluid flows through a tube (catheter) into part of your abdomen and filters waste ...

  18. Climatic controls of interannual variability in regional carbon fluxes from top-down and bottom-up perspectives

    NASA Astrophysics Data System (ADS)

    Desai, Ankur R.; Helliker, Brent R.; Moorcroft, Paul R.; Andrews, Arlyn E.; Berry, Joseph A.

    2010-06-01

    Observations of regional net ecosystem exchange (NEE) of CO2 for 1997-2007 were analyzed for climatic controls on interannual variability (IAV). Quantifying IAV of regional (104-106 km2) NEE over long time periods is key to understanding potential feedbacks between climate and the carbon cycle. Four independent techniques estimated monthly regional NEE for 104 km2 in a spatially heterogeneous temperate-boreal transition region of the north central United States, centered on the Park Falls, Wisconsin, United States, National Oceanic and Atmospheric Administration tall tower site. These techniques included two bottom-up methods, based on flux tower upscaling and forest inventory based demographic modeling, respectively, and two top-down methods, based on tall tower equilibrium boundary layer budgets and tracer-transport inversion, respectively. While all four methods revealed a moderate carbon sink, they diverged significantly in magnitude. Coherence of relative magnitude and variability of NEE anomalies was strong across the methods. The strongest coherence was a trend of declining carbon sink since 2002. Most climatic controls were not strongly correlated with IAV. Significant controls on IAV were those related to hydrology, such as water table depth, and atmospheric CO2. Weaker relationships were found with phenological controls such as autumn soil temperature. Hydrologic relationships were strongest with a 1 year lag, potentially highlighting a previously unrecognized predictor of IAV in this region. These results highlight a need for continued development of techniques to estimate regional IAV and incorporation of hydrologic cycling into couple carbon-climate models.

  19. Elevated carbon dioxide alters impacts of precipitation pulses on ecosystem photosynthesis and respiration in a semi-arid grassland

    USDA-ARS?s Scientific Manuscript database

    Predicting net carbon (C) balance under future global change scenarios requires a comprehensive understanding of photosynthetic (GPP) and ecosystem respiration (Re) responses to atmospheric CO2 concentration and water availability. We measured net ecosystem exchange of CO2 (NEE), GPP and Re prior to...

  20. Continuum estimates of rotational dielectric friction and polar solvation

    SciTech Connect

    Maroncelli, M.

    1997-01-01

    Dynamical solvation data recently obtained with the probe solute coumarin 153 are used to test the reliability of dielectric continuum models for estimating dielectric friction effects. In particular, the predictions of the Nee{endash}Zwanzig theory of rotational dielectric friction are examined in some detail. The analysis undertaken here uncovers an error made in virtually all previous applications of the Nee{endash}Zwanzig formalism. The error involves neglect of the solvent{close_quote}s electronic polarizability when calculating dielectric friction constants. In highly polar solvents the effect of this neglect is shown to be minor, so that the results of past studies should not be appreciably altered. However, in weakly polar and especially in nondipolar solvents, the proper inclusion of electronic polarizability terms is essential. The equivalence between the Nee{endash}Zwanzig theory of dielectric friction and more general continuum treatments of polar solvation dynamics is also demonstrated. This equivalence enables the use of solvation data to test the reliability of the Nee{endash}Zwanzig description of electrical interactions between a solute and solvent that form the core of this and related continuum theories of dielectric friction. Comparisons to experimental data show that, with the important exception of nondipolar solvents, such continuum treatments provide reasonably accurate ({plus_minus}40{percent}) predictors of time-dependent solvation and/or dielectric friction. {copyright} {ital 1997 American Institute of Physics.}

  1. Climatic versus biotic constraints on carbon and water fluxes in seasonally drought-affected ponderosa pine ecosystems

    NASA Astrophysics Data System (ADS)

    Schwarz, P. A.; Law, B. E.; Williams, M.; Irvine, J.; Kurpius, M.; Moore, D.

    2004-12-01

    We investigated the relative importance of climatic versus biotic controls on gross primary production (GPP) and water vapor fluxes in seasonally drought-affected ponderosa pine forests. The study was conducted in young (YS), mature (MS), and old stands (OS) over 4 years at the AmeriFlux Metolius sites. Model simulations showed that interannual variation of GPP did not follow the same trends as precipitation, and effects of climatic variation were smallest at the OS (<10%), largest at the MS (>50%), and intermediate at the YS (<20%). In the young, developing stand, interannual variation in leaf area has larger effects on fluxes than climate, although leaf area is a function of climate in that climate can interact with age-related shifts in carbon allocation and affect whole-tree hydraulic conductance. Older forests, with well-established root systems, appear to be better buffered from effects of seasonal drought and interannual climatic variation. Interannual variation of net ecosystem exchange (NEE) was also lowest at the OS, where NEE is controlled more by interannual variation of ecosystem respiration, 70% of which is from soil, than by the variation of GPP, whereas variation in GPP is the primary reason for interannual changes in NEE at the YS and MS. Across spatially heterogeneous landscapes with high frequency of younger stands resulting from natural and anthropogenic disturbances, interannual climatic variation and change in leaf area are likely to result in large interannual variation in GPP and NEE.

  2. 75 FR 74036 - Combined Notice of Filings #1

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-30

    ...-001. Applicants: The Trustees of the University of Pennsylvania. Description: McNees Wallace & Nurick LLC council to The Trustees of the University of PA, a PA Non-Profit Corp requests a shortened.... Docket Numbers: ER11-2157-000. Applicants: EWO Marketing, Inc. Description: EWO Marketing, Inc....

  3. Reply to DJ Millward

    USDA-ARS?s Scientific Manuscript database

    The objective of this Letter to the Editor was to clarify the tenets underlying a mathematical model of energy flux characterizing the obesity epidemic. 1. The obesity epidemic is attributed to an increase in energy intake, since the drop in physical activity energy expenditure (PAEE) that would nee...

  4. Blood Tests

    MedlinePlus

    ... as the kidneys, liver, thyroid, and heart—are working Diagnose diseases and conditions such as cancer, HIV/AIDS, diabetes, anemia (uh-NEE-me-eh), and coronary heart disease Find out whether you have risk factors ... taking are working Assess how well your blood is clotting Overview ...

  5. Insect pests and diseases in bioenergy crops

    USDA-ARS?s Scientific Manuscript database

    Louisiana sugarcane, Saccharum spp., and other grassy crops (e.g., grain sorghum, Sorghum bicolor (L.) Moench, and hybrids involving sugarcane; sorghum; sudangrass, Sorghum bicolor ssp. drummondii (Nees ex Steud.) de Wet and Harlan, and others) with potential for bioenergy production are susceptible...

  6. Root expression from a Beta vulgaris promoter in transgenic Arabidopsis plants

    USDA-ARS?s Scientific Manuscript database

    Tighter control of gene expression can be achieved by using promoters for expressing genes in a tissue-specific and temporal manner without imparting deleterious effects on non-target tissue. Inducible gene promoters that are specifically activated by pathogen invasion or insect pest attack are nee...

  7. Effects of rodent-induced land degradation on ecosytem carbon fluxes in alpine meadow in the Qinghai-Tibet Plateau, China

    NASA Astrophysics Data System (ADS)

    Peng, F.; Quangang, Y.; Xue, X.; Guo, J.; Wang, T.

    2014-10-01

    Land degradation induced by rodent activities is extensively occurred in alpine meadow ecosystem in the Qinghai-Tibet Plateau that would affect the ecosystem carbon (C) balance. We conducted a field experiment with six levels of land degradation (D1-D6, degradation aggravates from D1 to D6) to investigate the effects of land degradation on ecosystem C fluxes. Soil respiration (Rs), net ecosystem exchange (NEE), ecosystem respiration (ER) and gross ecosystem production (GEP) were measured from June to September 2012. Soil respiration, ER, GEP and above-ground biomass (AGB) was significantly higher in slightly degraded (D3 and D6) than in severely degraded land (D1, D2, D4 and D5). Positive averages of NEE in the growing season indicate that alpine meadow ecosystem is a weak C sink during the growing season. Net ecosystem exchange had no significant difference among different degraded levels, but the average NEE in slightly degraded group was 33.6% higher than in severely degraded group. Soil respiration, ER and NEE were positively correlated with AGB whereas soil organic C, labile soil C, total nitrogen (N) and inorganic nitrogen were associated with root biomass (RB). Our results highlight the decline of vegetation C storage of alpine meadow ecosystem with increasing number of rodent holes and suggest the control of AGB on ecosystem C fluxes, and the control of RB on soil C and N with development of land degradation.

  8. Age-dependent changes in ecosystem carbon fluxes in managed forests in Northern Wisconsin, USA

    Treesearch

    Asko Noormets; Jiquan Chen; Thomas R. Crow

    2007-01-01

    The age-dependent variability of ecosystem carbon (C) fluxes was assessed by measuring the net ecosystem exchange of C (NEE) in five managed forest stands in northern Wisconsin, USA. The study sites ranged in age from 3-year-old clearcut to mature stands (65 years). All stands, except the clearcut, accumulated C over the study period from May to October 2002. Seasonal...

  9. Relationship between field resistance to Phytophthora ramorum and constitutive phenolic chemistry of coast live oak

    Treesearch

    A.M. Nagle; B.A. McPherson; D.L. Wood; M. Garbelotto; A.O. Conrad; S. Opiyo; P. Bonello

    2012-01-01

    Sudden oak death, caused by Phytophthora ramorum, has resulted in high levels of coast live oak (Quercus agrifolia Nee (CLO) mortality. However, some CLO survive in areas with high disease pressure and may thus be resistant. We tested the hypothesis that such field resistant trees contain constitutively higher levels of...

  10. Consequences of cool-season drought induced plant mortality to Chihuahuan Desert grassland ecosystem and soil respiration dynamics

    USDA-ARS?s Scientific Manuscript database

    Global climate change is predicted to increase the severity and frequency of cool-season drought across the arid Southwest US. We quantified net ecosystem carbon dioxide exchange (NEE), ecosystem respiration (Reco), and gross ecosystem photosynthesis (GEP) in response to interannual seasonal precip...

  11. Riparian valley oak (Quercus lobata) forest restoration on the middle Sacramento River, California

    Treesearch

    F. Thomas Griggs; Gregory H. Golet

    2002-01-01

    In 1989 The Nature Conservancy initiated a riparian horticultural restoration program on the floodplain of the middle Sacramento River, California. At nearly all restoration sites Valley oak (Quercus lobata Nee) comprised a major component of the planting design. Valley oaks are a keystone tree species of lowland floodplain habitats in California...

  12. Antioxidant Effect of Nanoemulsions Containing Extract of Achyrocline satureioides (Lam) D.C.-Asteraceae.

    PubMed

    Zorzi, Giovanni Konat; Caregnato, Fernanda; Moreira, José Cláudio Fonseca; Teixeira, Helder Ferreira; Carvalho, Edison Luis Santana

    2016-08-01

    Ethanolic extracts of Achyrocline satureioides have pronounced antioxidant activity mainly due to the presence of the flavonoid quercetin. However, direct topical application of the extract is not possible due to the presence of high amounts of ethanol. In this sense, nanoemulsions arise as an alternative for topical formulation associating molecules with limited aqueous solubility. This article describes the development of topical nanoemulsions containing either A. satureioides extract or one of its most abundant flavonoid, quercetin. Nanoemulsions composed of octyldodecanol, egg lecithin, water and extract (NEE), or quercetin (NEQ) were prepared by spontaneous emulsification. This process led to monodisperse nanoemulsions presenting a mean droplet size of approximately 200-300 nm, negative zeta potential, and high association efficiency. A study of quercetin skin retention using porcine skin which was performed using a Franz diffusion cell revealed a higher accumulation of quercetin in skin for NEE when compared to NEQ. Finally, the antioxidant activity of formulations was measured by thiobarbituric acid-reactive species and the APPH model. A lower lipoperoxidation for the extract in respect to quercetin solution was observed. However, no difference between NEQ and NEE lipoperoxidation could be seen. The protection against lipoperoxidation by the formulations was also measured in the skin, where lower formation of reactive species was observed after treatment with NEE. In conclusion, this study shows the formulation effect on the physicochemical properties of nanoemulsions as well as on the skin retention and antioxidant activity of quercetin.

  13. Electrochemical immunosensor based on ensemble of nanoelectrodes for immunoglobulin IgY detection: application to identify hen's egg yolk in tempera paintings.

    PubMed

    Bottari, Fabio; Oliveri, Paolo; Ugo, Paolo

    2014-02-15

    A nanostructured electrochemical biosensor for detecting proteins of interest in work of art, in particular in tempera paintings, is presented. To determine egg yolk we focus here on the determination of immunoglobulin IgY. The transducers are nanoelectrode ensembles (NEEs), prepared via membrane templated electroless deposition of gold. Because of their geometrical and diffusion characteristics, NEEs are characterized by significantly low detection limits, moreover they display the capability of capturing proteins by interaction with the polycarbonate membrane of the NEE. At first, the proteic component of the paint is extracted by ultrasonication in an aqueous buffer, then IgY is captured by incubation on the NEE. The immunoglobulin is detected by treatment with anti-IgY labeled with horse radish peroxidase (Anti-IgY-HRP). The binding of the Anti-IgY-HRP is detected by recording the electrocatalytic signal caused by addition of H2O2 and methylene blue. The sensor detection capabilities are tested by analyzing both paint models, prepared in the lab, and real samples, from paintings of the XVIII-XX century. Multivariate exploratory analysis is applied to classify the voltammetric patterns, confirming the capability to differentiate egg-yolk tempera from other kind of tempera binders as well as from acrylic or oil paints.

  14. Thermal adaptation of net ecosystem exchange

    USDA-ARS?s Scientific Manuscript database

    Thermal adaptation of gross primary production and ecosystem respiration has been well documented over broad thermal gradients. However, no study has examined their interaction as a function of temperature, i.e. the thermal responses of net ecosystem exchange of carbon (NEE). In this study, we const...

  15. The soil moisture active passive validation experiment 2012 (SMAPVEX12): pre-launch calibration and validation of the SMAP satellite

    USDA-ARS?s Scientific Manuscript database

    The National Aeronautics and Space Administration (NASA) Soil Moisture Active Passive (SMAP) satellite is scheduled for launch in November 2014. In order to develop robust soil moisture retrieval algorithms that fully exploit the unique capabilities of SMAP, algorithm developers had identified a nee...

  16. Linda S. Gottfredson

    ERIC Educational Resources Information Center

    Wainer, Howard; Robinson, Daniel H.

    2009-01-01

    This article presents an interview with Linda Gottfredson (nee Howarth), who obtained her BA (psychology, Phi Beta Kappa) from UC Berkeley in 1969, served in the Peace Corps in the Malaysian Health Service from 1969 to 1972, and received her PhD (sociology) from Johns Hopkins University (JHU) in 1976. She was Research Scientist at JHU's Center for…

  17. First report of Laurel Wilt caused by Rafffaelea lauricola on sassafras in Mississippi

    Treesearch

    J.J. Riggins; S.W. Fraedrich; T.C. Harrington

    2011-01-01

    Laurel wilt is caused by the fungus Raffaelea lauricola T.C. Harrin., Aghayeva & Fraedrich and is lethal to redbay (Persea borbonia (L.) Spreng.), sassafras (Sassafras albidum (Nutt.) Nees), and other species in the Lauraceae (1). The fungus is carried by the redbay ambrosia beetle (Xyleborus glabratus Eichh.), which is native to Asia.

  18. Biomedical Cost of Low Level Flight in a Hot Environment

    DTIC Science & Technology

    1975-01-01

    orining almilistrative duties oil the ground. Flights were nected , ia breakawkay plug to a signal conditioner in the classified as low% level if they had...bsr\\L1101gW0 dinlo Edgar Williams and ’I’Sgi David 1-reeze assisted with) the chemi- itdtsc obcrscd intng \\’ ~s lurng ot cal airlyses Mr kiehard Mc.Nee

  19. Insect-oak interactions with coast live oak (Quercus agrifolia) and Engelmann oak (Q. engelmannii) at the acorn and seedling stage

    Treesearch

    Connell E. Dunning; Timothy D. Paine; Richard A. Redak

    2002-01-01

    We determined the impact of insects on both acorns and seedlings of coast live oak (Quercus agrifolia Nee) and Engelmann oak (Quercus engelmannii E. Greene). Our goals were to (1) identify insects feeding on acorns and levels of insect damage, and (2) measure performance and preference of a generalist leaf-feeding insect herbivore...

  20. Compensatory water effects link yearly global land CO2 sink changes to temperature.

    PubMed

    Jung, Martin; Reichstein, Markus; Schwalm, Christopher R; Huntingford, Chris; Sitch, Stephen; Ahlström, Anders; Arneth, Almut; Camps-Valls, Gustau; Ciais, Philippe; Friedlingstein, Pierre; Gans, Fabian; Ichii, Kazuhito; Jain, Atul K; Kato, Etsushi; Papale, Dario; Poulter, Ben; Raduly, Botond; Rödenbeck, Christian; Tramontana, Gianluca; Viovy, Nicolas; Wang, Ying-Ping; Weber, Ulrich; Zaehle, Sönke; Zeng, Ning

    2017-01-26

    Large interannual variations in the measured growth rate of atmospheric carbon dioxide (CO2) originate primarily from fluctuations in carbon uptake by land ecosystems. It remains uncertain, however, to what extent temperature and water availability control the carbon balance of land ecosystems across spatial and temporal scales. Here we use empirical models based on eddy covariance data and process-based models to investigate the effect of changes in temperature and water availability on gross primary productivity (GPP), terrestrial ecosystem respiration (TER) and net ecosystem exchange (NEE) at local and global scales. We find that water availability is the dominant driver of the local interannual variability in GPP and TER. To a lesser extent this is true also for NEE at the local scale, but when integrated globally, temporal NEE variability is mostly driven by temperature fluctuations. We suggest that this apparent paradox can be explained by two compensatory water effects. Temporal water-driven GPP and TER variations compensate locally, dampening water-driven NEE variability. Spatial water availability anomalies also compensate, leaving a dominant temperature signal in the year-to-year fluctuations of the land carbon sink. These findings help to reconcile seemingly contradictory reports regarding the importance of temperature and water in controlling the interannual variability of the terrestrial carbon balance. Our study indicates that spatial climate covariation drives the global carbon cycle response.

  1. Use of Glyphosate and Imazapyr for Cogongrass (Imperata cylindrica) management in southern pine forests

    Treesearch

    Patrick J. Minogue; James H. Miller; Dwight K. Lauer

    2012-01-01

    Cogongrass (Imperata cylindrica [L.] P. Beauv. var. major [Nees] C.E. Hubb) is one of the most invasive perennial grasses worldwide and has progressively infested managed and natural habitats in the mid-South over the past 100 years. To extend past research toward the goal of eradication on forested sites, we tested the most effective herbicides (glyphosate and...

  2. 76 FR 42750 - National Science Board: Sunshine Act Meetings; Notice

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-19

    ... Information Item: iPlant Annual Report on Award Progress NSB Information Item: National Ecological Observatory Network (NEON) Update NSB Information Item: Network for Earthquake Engineering Simulation (NEES) Update... visitors must report to the NSF visitor desk at the 9th and N. Stuart Streets entrance to receive a...

  3. Compensatory Water Effects Link Yearly Global Land CO2 Sink Changes to Temperature

    NASA Technical Reports Server (NTRS)

    Jung, Martin; Reichstein, Markus; Tramontana, Gianluca; Viovy, Nicolas; Schwalm, Christopher R.; Wang, Ying-Ping; Weber, Ulrich; Weber, Ulrich; Zaehle, Soenke; Zeng, Ning; hide

    2017-01-01

    Large interannual variations in the measured growth rate of atmospheric carbon dioxide (CO2) originate primarily from fluctuations in carbon uptake by land ecosystems13. It remains uncertain, however, to what extent temperature and water availability control the carbon balance of land ecosystems across spatial and temporal scales314. Here we use empirical models based on eddy covariance data15 and process-based models16,17 to investigate the effect of changes in temperature and water availability on gross primary productivity (GPP), terrestrial ecosystem respiration (TER) and net ecosystem exchange (NEE) at local and global scales. We find that water availability is the dominant driver of the local interannual variability in GPP and TER. To a lesser extent this is true also for NEE at the local scale, but when integrated globally, temporal NEE variability is mostly driven by temperature fluctuations. We suggest that this apparent paradox can be explained by two compensatory water effects. Temporal water-driven GPP and TER variations compensate locally, dampening water-driven NEE variability. Spatial water availability anomalies also compensate, leaving a dominant temperature signal in the year-to-year fluctuations of the land carbon sink. These findings help to reconcile seemingly contradictory reports regarding the importance of temperature and water in controlling the interannual variability of the terrestrial carbon balance36,9,11,12,14. Our study indicates that spatial climate covariation drives the global carbon cycle response.

  4. Modelling the limits on the response of net carbon exchange to fertilization in a south-eastern pine forest

    Treesearch

    Chun-Tai. Lai; G. Katul; J. Butnor; M. Siqueira; D. Ellsworth; C. Maier; Kurt Johnsen; S. Mickeand; R. Oren

    2002-01-01

    Using a combination of model simulations and detailed measurements at a hierarchy of scales conducted at a sandhills forest site, the effect of fertilization on net ecosystem exchange (NEE) and its components in 6-year-old Pinus taeda stands was quantified. The detailed measurements, collected over a 20-d period in September and October, included gas...

  5. EPA DETERMINATION STUDIES ON THE CONTROL OF TOXIC AIR POLLUTION EMISSIONS FROM ELECTRIC UTILITY BOILERS

    EPA Science Inventory

    The U. S. Environmental Protection Agency (EPA) is to determine whether the regulation of hazardous air pollution (HAP) emissions from electric utility generating plants is necessary. This determination is to be made on or before December 15, 2000. It focuses primarily on the nee...

  6. Carbon dioxide and water vapour exchange in a tropical dry forest as influenced by the North American Monsoon System (NAMS)

    USDA-ARS?s Scientific Manuscript database

    To better understand the effects and relationship between precipitation, net ecosystem carbon dioxide (NEE) and water vapor exchange (ET), we report a study conducted in the tropical dry forest (TDF) in the northwest of Mexico. Ecosystem gas exchange was measured using the eddy correlation technique...

  7. Rh Incompatibility

    MedlinePlus

    ... attack the baby's red blood cells. This can lead to hemolytic anemia (HEE-moh-lit-ick uh-NEE-me-uh) ... baby won't get enough oxygen. This can lead to serious problems. Severe hemolytic anemia may even be fatal to the child. Outlook ...

  8. Complex conductivity response to silver nanoparticles in partially saturated sand columns

    EPA Science Inventory

    The increase in the use of nanoscale materials in consumer products has resulted in a growing concern of their potential hazard to ecosystems and public health from their accidental or intentional introduction to the environment. Key environmental, health, and safety research nee...

  9. Dynamic evolution of precise regulatory encodings creates the clustered site signature of enhancers

    PubMed Central

    Crocker, Justin; Potter, Nathan; Erives, Albert

    2010-01-01

    Concentration gradients of morphogenic proteins pattern the embryonic axes of Drosophila by activating different genes at different concentrations. The neurogenic ectoderm enhancers (NEEs) activate different genes at different threshold levels of the Dorsal (Dl) morphogen, which patterns the dorsal/ventral axis. NEEs share a unique arrangement of highly constrained DNA-binding sites for Dl, Twist (Twi), Snail (Sna) and Suppressor of Hairless (Su(H)), and encode the threshold variable in the precise length of DNA that separates one well-defined Dl element from a Twi element. However, NEEs also possess dense clusters of variant Dl sites. Here, we show that these increasingly variant sites are eclipsed relic elements, which were superseded by more recently evolved threshold encodings. Given the divergence in egg size during Drosophila lineage evolution, the observed characteristic clusters of divergent sites indicate a history of frequent selection for changes in threshold responses to the Dl morphogen gradient and confirm the NEE structure/function model. PMID:20981027

  10. Contrasting effects of invasive insects and fire on ecosystem water use efficiency

    Treesearch

    K.L. Clark; N.S. Skowronski; M.R. Gallagher; H. Renninger; K.V.R. Schäfer

    2014-01-01

    We used eddy covariance and meteorological measurements to estimate net ecosystem exchange of CO2 (NEE), gross ecosystem production (GEP), evapotranspiration (Et), and ecosystem water use efficiency (WUEe; calculated as GEP / Et during dry canopy conditions) in three upland forests in the New Jersey Pinelands, USA, that were defoliated by gypsy...

  11. Indicators and Methods for Constructing a U.S. Human Well-being Index (HWBI) for Ecosystem Services Research

    EPA Science Inventory

    Humans are dependent upon the services provided by nature, and unless we effectively account for the range of values from ecosystems in our efforts to protect the environment, we cannot sustain human well-being. In light of this dependence, a national measure of well-being is nee...

  12. Complex conductivity response to silver nanoparticles in partially saturated sand columns

    EPA Science Inventory

    The increase in the use of nanoscale materials in consumer products has resulted in a growing concern of their potential hazard to ecosystems and public health from their accidental or intentional introduction to the environment. Key environmental, health, and safety research nee...

  13. Exploring the Adolescent's Creative Pathways: Mindfulness, Role Fluidity, Story, and the Dramatic Curriculum

    ERIC Educational Resources Information Center

    McNees, David

    2015-01-01

    David McNees' deep foray into creativity theory and drama begins with mindfulness as a preparation for adolescent focus. This article discusses role incarnation, the correlation of the three-period lesson to Landy's role theory, the creation and re-creation of personal story and identity, archetypal heroes, and how the adaptability learned in…

  14. Splinter Protection for Airbase Firefighting Resources

    DTIC Science & Technology

    1989-12-01

    Hardened Construction, Shotcret , Corrugated Steel Pipe, Ccnventional Weapons. - 19.IVSTRACT (Continue on reverse if nee.•sry and identify by block...structure with a concrete floor and the other con- sisted of a reinforced concrete ( shotcrete ) arch. A suggested test plan is included for field testing the...13 5. Cost ........................................... 14 G. SHOTCRETE ARCH .................................... 14 1. Constructibility

  15. Lemongrass productivity oil content and composition as a function of nitrogen sulfur and harvest time

    USDA-ARS?s Scientific Manuscript database

    Lemongrass [Cymbopogon flexuosus (Steud.) Wats, (syn. Andropogon nardus var. flexuosus Hack; A. flexuosus Nees)] is one of the most widely grown essential oil plants in the world. Field experiments were conducted at Verona and Poplarville, Mississippi, to evaluate the effects of N (0, 40, 80, and 16...

  16. A new Gonatocerus (Hymenoptera:Mymaridae) from Argentina, with taxonomic notes and molecular data on the G. tuberculifemur species complex

    USDA-ARS?s Scientific Manuscript database

    Gonatocerus deleoni Triapitsyn, Logarzo & Virla sp. n., reared from sentinel eggs of Tapajosa rubromarginata (Signoret) (Cicadellidae: Cicadellinae: Proconiini) on citrus plants, a new member of the ater species group of Gonatocerus Nees (Mymaridae), is described from the state of Mendoza, Argentina...

  17. A new species of Gonatocerus (Hymenoptera: Mymaridae) from Argentina, an egg parasitoid of Tapajosa rubromarginata (Hemiptera: Cleadellidae)

    USDA-ARS?s Scientific Manuscript database

    A new species from the ater species group of Gonatocerus Nees (Mymaridae) is described from Argentina. Specimens of G. virlai S. Triapitsyn, Logarzo & de León sp. n. were reared mostly from wild-collected and sentinel eggs of the proconiine sharpshooter Tapajosa rubromarginata (Signoret) (Cicadelli...

  18. A new Gonatocerus (Hymenoptera: Mymaridae) from Argentina, with taxonomic notes and molecular data on the G. tuberculifemur species complex

    USDA-ARS?s Scientific Manuscript database

    A new member of the ater species group of Gonatocerus Nees (Mymaridae) is described from the state of Mendoza in Argentina. Specimens of G. deleoni Triapitsyn, Logarzo & Virla sp. n. were first reared in San Rafael from sentinel eggs of the proconiine sharpshooter Tapajosa rubromarginata (Signoret) ...

  19. Registration of N614, A3N615, N616, and N617 Shattercane Genetic Stocks with cytoplasmic or nuclear male-sterility and juicy or dry midribs

    USDA-ARS?s Scientific Manuscript database

    Four shattercane [Sorghum bicolor subsp. drummondii (Nees ex Steud) de Wet & Harlan] genetic stocks, N614, A3N615, N616, N617 (Reg. No. XXX, PI 665683 to 665686), with A3 cytoplasmic male-sterility or nuclear male-sterility gene ms3 containing either juicy (dd) or dry (DD) culms were developed joint...

  20. Collection and seed production of Allium acuminatum

    USDA-ARS?s Scientific Manuscript database

    As a component of Greater Sage-Grouse and Southern Idaho Ground Squirrel habitat, Allium acuminatum Hook. (Taper-tip onion) has been targeted for use in restoration projects and conservation. Before a native plant can be used in large or small projects in the landscape quantities of propagules nee...

  1. Comparing Simulated and Observed Gross Primary Productivity

    NASA Astrophysics Data System (ADS)

    Schaefer, K.

    2009-12-01

    As part of the North American Carbon Program (NACP) Site-level Interim Synthesis, we compare simulated and observed Gross Primary Productivity (GPP) from 21 models at 36 eddy covariance flux towers. Evaluation of terrestrial carbon models typically include comparison of simulated and observed Net Ecosystem Exchange (NEE) at eddy covariance Flux towers, but such comparisons rarely include ecosystem respiration (Re) and GPP because they are not directly measured and must be estimated from observed NEE. All 21 models participating in the NACP Site-Level Interim Synthesis ran simulations at each tower using a standard simulation protocol with gap-filled observed weather. The observed NEE at all 36 towers are partitioned into Re and GPP using a standard procedure. The gap-filled observed NEE, Re, and GPP include estimated uncertainties at multiple time scales due to random variability, gap-filling technique, friction velocity filtering, and flux partitioning. We quantify each model’s performance in reproducing the estimated GPP using uncertainty weighted cost functions, root-mean-square error (bias), correlations, and Taylor diagrams at the diurnal, seasonal, and annual time scales. We relate model performance to model characteristics, such as the type of photosynthesis model (light use efficiency vs. stomatal conductance), phenology (diagnostic vs. prognostic), values of common parameters, and representation of the physical environment (soil temperature, soil moisture, and vapor pressure deficit).

  2. The fundamental equation of eddy covariance and its application in flux measurements

    Treesearch

    Lianhong Gu; William J. Massman; Ray Leuning; Stephen G. Pallardy; Tilden Meyers; Paul J. Hanson; Jeffery S. Riggs; Kevin P. Hosman; Bai Yang

    2012-01-01

    A fundamental equation of eddy covariance (FQEC) is derived that allows the net ecosystem exchange (NEE) Ns of a specified atmospheric constituent s to be measured with the constraint of conservation of any other atmospheric constituent (e.g. N2, argon, or dry air). It is shown that if the condition [equation, see PDF] is true, the conservation of mass can be applied...

  3. Climatic Versus Biotic Constraints on Carbon and Water Fluxes in Seasonally Drought-affected Ponderosa Pine Ecosystems. Chapter 2

    NASA Technical Reports Server (NTRS)

    Schwarz, P. A.; Law, B. E.; Williams, M.; Irvine, J.; Kurpius, M.; Moore, D.

    2005-01-01

    We investigated the relative importance of climatic versus biotic controls on gross primary production (GPP) and water vapor fluxes in seasonally drought-affected ponderosa pine forests. The study was conducted in young (YS), mature (MS), and old stands (OS) over 4 years at the AmeriFlux Metolius sites. Model simulations showed that interannual variation of GPP did not follow the same trends as precipitation, and effects of climatic variation were smallest at the OS (50%), and intermediate at the YS (<20%). In the young, developing stand, interannual variation in leaf area has larger effects on fluxes than climate, although leaf area is a function of climate in that climate can interact with age-related shifts in carbon allocation and affect whole-tree hydraulic conductance. Older forests, with well-established root systems, appear to be better buffered from effects of seasonal drought and interannual climatic variation. Interannual variation of net ecosystem exchange (NEE) was also lowest at the OS, where NEE is controlled more by interannual variation of ecosystem respiration, 70% of which is from soil, than by the variation of GPP, whereas variation in GPP is the primary reason for interannual changes in NEE at the YS and MS. Across spatially heterogeneous landscapes with high frequency of younger stands resulting from natural and anthropogenic disturbances, interannual climatic variation and change in leaf area are likely to result in large interannual variation in GPP and NEE.

  4. [Net carbon exchange and its environmental affecting factors in a forest plantation in Badaling, Beijing of China].

    PubMed

    Tang, Xiang; Chen, Wen-Jing; Li, Chun-Yi; Zha, Tian-Shan; Wu, Bin; Wang, Xiao-Ping; Jia, Xin

    2013-11-01

    By using eddy covariance technique, a year-round (November, 2011-October, 2012) continuous measurement of net ecosystem carbon dioxide exchange (NEE) was conducted in a 4-year old mixed forest plantation in Badaling of Beijing. The forest plantation ecosystem was a net carbon sink in July and August, but a carbon source in the rest months. The monthly net carbon loss and uptake were the largest in April and July, respectively. The annual net ecosystem productivity was (-256 +/- 21) g C x m(-2) x a(-1), in which, the ecosystem respiration was (950 +/- 36) g C x m(-2) x a(-1), and the gross ecosystem productivity was (694 +/- 17) g C x m(-2) x a(-1). The nighttime NEE increased exponentially with the soil temperature at 10 cm depth, with the estimated temperature sensitivity of ecosystem respiration (Q10 ) being 2.2. During the growth season (May-September), the daytime NEE increased with photosynthetically active radiation (PAR) as described by the Michaelis-Menten rectangular hyperbola. The ecosystem quantum yield varied seasonally, ranging from 0.0219 micromol CO2 x micromol(-1) in May to 0.0506 micromol CO2 x micromol(-1) in July. The maximum carbon assimilation rate and the average daytime respiration followed the seasonal trends of PAR and air temperature. In July and August, vapor pressure deficit and soil moisture played a significant role in determining daytime NEE.

  5. A process-level evaluation of the spatiotemporal variability of CO2 fluxes predicted by terrestrial biosphere models using atmospheric data

    NASA Astrophysics Data System (ADS)

    Fang, Y.; Michalak, A. M.; Shiga, Y. P.; Yadav, V.

    2013-12-01

    Terrestrial biosphere models (TBMs) are used to extrapolate local observations and process-level understanding of land-atmosphere carbon exchange to larger regions, and can serve as a predictive tool for examining carbon-climate interactions and global change. Understanding and improving the performance of TBMs is thus crucial to the carbon cycle research community. In this work, we evaluate the spatiotemporal patterns of net ecosystem exchange (NEE) simulated by TBMs using atmospheric CO2 observations and a Geostatistical Inverse Modeling (GIM) framework. The evaluation methodology is based on the ability (or inability) of the spatiotemporal patterns in NEE estimates to explain the variability observed in atmospheric CO2 distribution. More simply, we examine whether the spatiotemporal patterns of NEE simulated by TBMs (including CASA-GFED, ORCHIDEE, VEGAS2 and SiB3) are consistent with the variations observed in the atmosphere. A similar GIM methodology is also applied using environmental variables (such as water availability, temperature, radiation, etc.) rather than TBMs, to explore the environmental processes associated with the variability of NEE, and determine which processes are associated with good/poor performance in TBMs. We find that NEE simulated by TBMs is consistent with that seen by atmospheric measurements more often during growing season months (Apr-Sept) than during the non-growing season. Over Temperate Broadleaf and Mixed Forests, Temperate Coniferous Forests and Temperate Grasslands, Savannas and Shrublands, atmospheric measurements are sufficiently sensitive to NEE fluxes to constrain the evaluation of model performance during the majority of the year (about 7-8 months in a year, mostly in growing season). For these regions and months, at least one of the TBMs is found to be able to reproduce the observed variability, but the most representative TBM varies by region and month. For the remaining months, none of the TBMs are able to reproduce

  6. Variation in Factors Regulating Net Greenhouse Gas Exchange Across Different Vegetation Types at Cape Bounty, Melville Island, Nunavut

    NASA Astrophysics Data System (ADS)

    Scott, N. A.; Blaser, A.; Buckley, E.; Humphreys, E.; Treitz, P.

    2015-12-01

    Global-scale climate simulations predict significant changes both in temperature and moisture regimes in the high Arctic. This could lead to changes in vegetation community distribution, as vegetation communities are distributed along moisture gradients often determined by snowfall patterns across the landscape. Furthermore, changes in soil moisture and temperature could alter fluxes of greenhouse gases such as carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), and the impacts of changes in these controlling factors could vary by vegetation type.We measured both spatial and temporal variation in CO2 fluxes using combinations of eddy covariance, auto-chamber, and static chamber techniques at the Cape Bounty Arctic Watershed Observatory (CBAWO). Measurements were performed in three major plant community types: polar semi-desert (PSD), mid-moisture tundra (MM) and wet sedge meadow (WS). Based on our auto-chamber data collected in all vegetation types, ecosystem respiration (ER) related positively to air temperature, and correlated more strongly with air temperature than soil temperature. Modeled ER based on eddy covariance data and air temperature over MM agreed well with measured ER in the same vegetation type. In the WS community, average net ecosystem exchange (NEE) in 2014 measured by static chambers differed in spectrally separable 'wet' and 'dry' sedge areas (-0.33 and 0.01 µmol m-2 s-1, respectively; p<0.001). Rates of ER also varied across this moisture gradient (p<0.05). Over the entire growing season and multiple years, NEE correlated poorly with air and soil temperature, suggesting that ER is not the dominant processes driving NEE. This can vary, however, over the growing season. In PSD communities measured in 2013, air temperature related positively to NEE early in the growing season, but not during the latter part of the season, when PAR (photosynthesis) became the key factor controlling NEE. Not surprisingly, NEE related strongly (0.93) to

  7. Isotopic air sampling in a tallgrass prairie to partition net ecosystem CO2 exchange

    NASA Astrophysics Data System (ADS)

    Lai, Chun-Ta; Schauer, Andrew J.; Owensby, Clenton; Ham, Jay M.; Ehleringer, James R.

    2003-09-01

    Stable isotope ratios of various ecosystem components and net ecosystem exchange (NEE) CO2 fluxes were measured in a C3-C4 mixture tallgrass prairie near Manhattan, Kansas. The July 2002 study period was chosen because of contrasting soil moisture contents, which allowed us to address the effects of drought on photosynthetic CO2 uptake and isotopic discrimination. Significantly higher NEE fluxes were observed for both daytime uptake and nighttime respiration during well-watered conditions when compared to a drought period. Given these differences, we investigated two carbon-flux partitioning questions: (1) What proportions of NEE were contributed by C3 versus C4 species? (2) What proportions of NEE fluxes resulted from canopy assimilation versus ecosystem respiration? To evaluate these questions, air samples were collected every 2 hours during daytime for 3 consecutive days at the same height as the eddy covariance system. These air samples were analyzed for both carbon isotope ratios and CO2 concentrations to establish an empirical relationship for isoflux calculations. An automated air sampling system was used to collect nighttime air samples to estimate the carbon isotope ratios of ecosystem respiration (δR) at weekly intervals for the entire growing season. Models of C3 and C4 photosynthesis were employed to estimate bulk canopy intercellular CO2 concentration in order to calculate photosynthetic discrimination against 13C. Our isotope/NEE results showed that for this grassland, C4 vegetation contributed ˜80% of the NEE fluxes during the drought period and later ˜100% of the NEE fluxes in response to an impulse of intense precipitation. For the entire growing season, the C4 contribution ranged from ˜68% early in the spring to nearly 100% in the late summer. Using an isotopic approach, the calculated partitioned respiratory fluxes were slightly greater than chamber-measured estimates during midday under well-watered conditions. In addition, time series

  8. Development of an Implementation Plan for Atmospheric Carbon Monitoring in California

    SciTech Connect

    Fischer, Marc L.; Riley, William J.; Tonse, Shaheen

    2004-10-01

    This report describes the design of atmospheric CO{sub 2} concentration measurements that, in combination with other measurements and models, would be used to quantify regionally distributed CO{sub 2} exchanges from California's terrestrial ecosystems and CO{sub 2} emissions from fossil fuel combustion. Using models of net ecosystem CO{sub 2} exchange (NEE), fossil fuel CO{sub 2} emissions, and regional meteorology, we predict CO{sub 2} concentration ''signals'' in the atmosphere. The predictions of NEE exhibit spatial and temporal variations that are controlled by land cover and climate. Fossil fuel CO{sub 2} emissions from metropolitan areas are the strongest localized sources of CO{sub 2} while weaker but spatially extensive fossil emissions are present throughout the Central Valley. We subdivide the CO{sub 2} sources into four components: NEE inside and outside CA, and fossil fuel CO{sub 2} inside and outside CA. Maps of predicted atmospheric CO{sub 2} concentration signals from these four sources largely mirror the instantaneous emissions near strong sources but plumes of CO{sub 2} enriched or depleted air are predicted to advect far from their sources. We then identify a baseline set of observing stations from existing and possible future sites that could be used to characterize in-state and out-of-state ecosystem and fossil fuel contributions to atmospheric CO{sub 2} concentrations. For each of the stations we calculate mean midday concentration signals with standard deviation for each month and source. We also calculate the covariance of the signal due to NEE inside CA with each of the other signals to quantify how much of the signal from NEE inside CA might be readily separable from the other signals. On the basis of these predictions, we identify new observing stations and a measurement protocol that, in combination with existing stations, would provide data to estimate NEE within CA. Although beyond the scope of this project, future work should estimate

  9. What drives the interannual variations in carbon fluxes and balance in a tropical rainforest of French Guiana?

    NASA Astrophysics Data System (ADS)

    Aguilos, M. M.; Burban, B.; Wagner, F. H.; Hérault, B.; Bonal, D.

    2016-12-01

    Amazon rainforest - a major contributor to the global carbon sink, is not on steady state and this affects terrestrial carbon pools. Yet, information on the effect of climatic extremes to long-term carbon fluxes is lacking. Thus, using an 11-year eddy covariance data, we examined the carbon fluxes and net carbon uptake in French Guiana's tropical rainforest to determine the interannual and seasonal variations in gross primary production (GPP), ecosystem respiration (RE) and net ecosystem exchange (NEE), so with climatic drivers influencing such changes from 2004 - 2014. GPP varies from 3394.9 g C m‒2 yr‒1 to 4054.5 g C m‒2 yr‒1. RE is more varied than GPP (3057.4 g C m‒2 yr‒1 - 3425.9 g C m‒2 yr‒1. NEE has large interannual variability from ‒68.2 g C m‒2 yr‒1 to ‒596.2 g C m‒2 yr‒1. NEE during wet seasons had higher sink strength than in dry periods. The sudden drop of RE during wet period in 2007 - 2009 may help explain this as it almost doubled the net uptake while GPP had slighter declines. The pattern of NEE appears to be driven by higher rate of increase in RE during dry season with less comparable rise in GPP. This suggests that over 11 years, the ecosystem did not suffer any extreme dry condition strong enough to induce severe decrease in RE. Annually, global radiation (Rg) explains 49% (P<0.0001) for GPP, 42% (P<0.0001) for RE, and 21% (P<0.0001) for NEE. During the wet season, Rg still controls GPP (r2 = 0.45; P <0.0001), RE (r2 = 0.30; P<0.0001;) and NEE (r2 = 0.31; P<0.0001). However, relative extractable water (REW) manifested more strongly during the dry period explaining mainly the variations of GPP (r2 = 0.20; P < 0.0001), RE (r2 = 0.33; P < 0.0001) and NEE (r2 = 0.25; P < 0.0001). Deep rooting system of trees may have caused GPP unsuppressed despite low soil moisture. Therefore, modeling studies must consider incorporating soil water measurements in deeper soils as most tropical trees are dependent on deep soil moisture

  10. Net ecosystem production in a Little Ice Age moraine: the role of plant functional traits

    NASA Astrophysics Data System (ADS)

    Varolo, E.; Zanotelli, D.; Tagliavini, M.; Zerbe, S.; Montagnani, L.

    2015-07-01

    Current glacier retreat allows vast mountain ranges available for vegetation establishment and growth. Little is known about the effective carbon (C) budget of these new ecosystems and how the presence of different vegetation communities, characterized by their specific physiology and life forms influences C fluxes. In this study, using a comparative analysis of the C fluxes of two contrasting vegetation types, we intend to evaluate if the different physiologies of the main species have an effect on Ecosystem Respiration (Reco), Gross Primary Production (GPP), annual cumulated Net Ecosystem Exchange (NEE), and long-term carbon accumulation in soil. The NEE of two plant communities present on a Little Ice Age moraine in the Matsch glacier forefield (Alps, Italy) was measured over two growing seasons. They are a typical C3 grassland, dominated by Festuca halleri All. and a community dominated by CAM rosettes Sempervivum montanum L. on rocky soils. Using transparent and opaque chambers, we extrapolated the ecophysiological responses to the main environmental drivers and performed the partition of NEE into Reco and GPP. Soil samples were collected from the same site to measure long-term C accumulation in the ecosystem. The two communities showed contrasting GPP but similar Reco patterns and as a result significantly different in NEE. The grassland acted mainly as a carbon sink with a total cumulated value of -46.4 ± 35.5 g C m-2 NEE while the plots dominated by the CAM rosettes acted as a source with 31.9 ± 22.4 g C m-2. In spite of the NEE being different in the two plant communities, soil analysis did not reveal significant differences in carbon accumulation. Grasslands showed 1.76 ± 0.12 kg C m-2, while CAM rosettes showed 2.06 ± 0.23 kg C m-2. This study demonstrates that carbon dynamics of two vegetation communities can be distinct even though the growing environment is similar. The physiological traits of the dominant species determine large differences in

  11. Year-round measurements of net ecosystem CO2 flux over a montane larch forest in Mongolia

    NASA Astrophysics Data System (ADS)

    Li, Sheng-Gong; Asanuma, Jun; Kotani, Ayumi; Eugster, Werner; Davaa, Gombo; Oyunbaatar, Dambaravjaa; Sugita, Michiaki

    2005-05-01

    Mongolian boreal forest merits special attention since it is located in the transitional area between the southern Siberian boreal forest and the Asian steppe zone, a vulnerable region being potentially affected by global warming and anthropogenic activities. This paper presents the first full-year-long continuous measurements of net ecosystem CO2 flux (NEE) made over a montane larch (Larix sibirica Ledeb.) forest in Mongolia from 25 March 2003 to 24 March 2004 (366 days) using the eddy covariance technique. The hourly maximum uptake was -10.1 μmol m-2 s-1. The maximum daily uptake of -4.0 g C m-2 d-1 (negative NEE values denote net carbon uptake by the canopy from the atmosphere) occurred in July. The annual cumulative NEE was -85 g C m-2, indicating that the forest acted as a net sink of CO2. We examined the responses of NEE to environmental conditions in the growing season from May to September. Both daytime 30-min mean and daily integrated NEE responded to incident photosynthetically active radiation (PAR) in a rectangular hyperbolic fashion. Model results show that the apparent quantum yield (α) was -0.0133 ± 0.0011 μmol CO2 per μmol of photons, and the bulk light use efficiency (LUE) on the daily basis was -6.7 mmol CO2 per mole of PAR photons over the entire growing season for this forest. Additionally, daily integrated NEE was also a linear function of the normalized difference vegetation index (NDVI), a linear function of mean daily air temperature (Ta), and a quadratic polynomial function of daily means of the atmospheric water vapor pressure deficit (VPD). Among these factors, LAI (as measured by NDVI) was dominant in affecting the dynamics of NEE, followed by Ta. Lower Ta was limiting the growth rate of this montane larch forest. As daily means of VPD exceeded 1.2 kPa, net CO2 uptake by the canopy declined. Nevertheless, water stress was not observed as a problem for the forest growth.

  12. Climate Effects on Carbon and Water Exchange of Young and Intermediate-growth Ponderosa Pine Ecosystems in Central Oregon

    NASA Astrophysics Data System (ADS)

    Kurpius, M. R.; Irvine, J.; Law, B. E.; Unsworth, M. H.

    2002-12-01

    Carbon and water fluxes were measured continuously by eddy covariance above young- and intermediate-aged ponderosa pine (Pinus ponderosa Dougl. Ex P. and C. Laws.) stands in a seasonally semiarid environment in central Oregon. Ecophysiological measurements of processes contributing to fluxes were also made (soil CO2 effluxes, transpiration). The young stand (YS) is ~17 years old, and has a total LAI of 1.5, with 40% of the leaf area in understory shrubs. The intermediate stand (IS), ~1.5 km from the YS, is ~56 years old, with total LAI ~3.1 (5% in understory shrubs). Our goal was to examine how seasonal weather patterns and age-related site characteristics affect CO2 and H2O exchange at these sites. Throughout the measurement period, water vapor exchange for both sites was similar in magnitude and trend. Net ecosystem exchange (NEE) was similar in magnitude (-1 to +1 mmol m-2 s-1) for both sites from January 2002 through March. As the rainy season ended, carbon uptake at both sites increased in April, and reached a maximum in early June. Early summer daytime mean NEE was greater at the IS (-6 to -8 mmol m-2 s-1) than at the YS (-3 to -4 mmol m-2 s-1). While the YS had higher summer soil CO2 efflux during this period, NEE remained higher at the IS due to higher GEP. Air temperature, vapor pressure deficit (VPD), and incident PAR were similar at both sites, but greater snow cover at the IS resulted in twice the soil moisture of the YS until July, when both sites reached low values (12% and 9%, respectively). A combination of higher leaf area and soil moisture likely accounts for higher early summer carbon uptake at the IS. NEE became strongly correlated with VPD in June as soil moisture levels were rapidly declining. VPD caused lowered NEE at both sites but the IS decreased more substantially than the YS and by mid-July NEE at both sites was -2 to -4 mmol m-2 s-1. Even with the diminished carbon uptake at the IS due to the strong coupling between VPD and NEE, we

  13. Net ecosystem carbon exchange of a dry temperate eucalypt forest

    NASA Astrophysics Data System (ADS)

    Hinko-Najera, Nina; Isaac, Peter; Beringer, Jason; van Gorsel, Eva; Ewenz, Cacilia; McHugh, Ian; Exbrayat, Jean-François; Livesley, Stephen J.; Arndt, Stefan K.

    2017-08-01

    Forest ecosystems play a crucial role in the global carbon cycle by sequestering a considerable fraction of anthropogenic CO2, thereby contributing to climate change mitigation. However, there is a gap in our understanding about the carbon dynamics of eucalypt (broadleaf evergreen) forests in temperate climates, which might differ from temperate evergreen coniferous or deciduous broadleaved forests given their fundamental differences in physiology, phenology and growth dynamics. To address this gap we undertook a 3-year study (2010-2012) of eddy covariance measurements in a dry temperate eucalypt forest in southeastern Australia. We determined the annual net carbon balance and investigated the temporal (seasonal and inter-annual) variability in and environmental controls of net ecosystem carbon exchange (NEE), gross primary productivity (GPP) and ecosystem respiration (ER). The forest was a large and constant carbon sink throughout the study period, even in winter, with an overall mean NEE of -1234 ± 109 (SE) g C m-2 yr-1. Estimated annual ER was similar for 2010 and 2011 but decreased in 2012 ranging from 1603 to 1346 g C m-2 yr-1, whereas GPP showed no significant inter-annual variability, with a mean annual estimate of 2728 ± 39 g C m-2 yr-1. All ecosystem carbon fluxes had a pronounced seasonality, with GPP being greatest during spring and summer and ER being highest during summer, whereas peaks in NEE occurred in early spring and again in summer. High NEE in spring was likely caused by a delayed increase in ER due to low temperatures. A strong seasonal pattern in environmental controls of daytime and night-time NEE was revealed. Daytime NEE was equally explained by incoming solar radiation and air temperature, whereas air temperature was the main environmental driver of night-time NEE. The forest experienced unusual above-average annual rainfall during the first 2 years of this 3-year period so that soil water content remained relatively high and the forest

  14. Turbulence Considerations for Comparing Ecosystem Exchange over Old-Growth and Clear-Cut Stands For Limited Fetch and Complex Canopy Flow Conditions

    SciTech Connect

    Wharton, S; Schroeder, M; Paw U, K T; Falk, M; Bible, K

    2009-01-08

    Carbon dioxide, water vapor and energy fluxes were measured using eddy covariance (EC) methodology over three adjacent forests in southern Washington State to identify stand-level age-effects on ecosystem exchange. The sites represent Douglas-fir forest ecosystems at two contrasting successional stages: old-growth (OG) and early seral (ES). Here we present eddy flux and meteorological data from two early seral stands and the Wind River AmeriFlux old-growth forest during the growing season (March-October) in 2006 and 2007. We show an alternative approach to the usual friction velocity (u*) method for determining periods of adequate atmospheric boundary layer (ABL) mixing based on the ratio of mean horizontal ({bar u}) and vertical ({bar w}) wind flow to a modified turbulent kinetic energy scale (uTKE). This new parameter in addition to footprint modeling showed that daytime CO{sub 2} fluxes (F{sub NEE}) in small clear-cuts (< 10 hectares) can be measured accurately with EC if micrometeorological conditions are carefully evaluated. Peak midday CO{sub 2} fluxes (F{sub NEE} = -14.0 to -12.3 {micro}mol m{sup -2} s{sup -1}) at OG were measured in April in both 2006 and 2007 before bud break when air and soil temperatures and vapor pressure deficit were relatively low, and soil moisture and light levels were favorable for photosynthesis. At the early seral stands, peak midday CO{sub 2} fluxes (F{sub NEE} = -11.0 to -8.7 {micro}mol m{sup -2} s{sup -1}) were measured in June and July while spring-time CO{sub 2} fluxes were much smaller (F{sub NEE} = -3.8 to -3.6 {micro}mol m{sup -2} s{sup -1}). Overall, we measured lower evapotranspiration (OG = 230 mm; ES = 297 mm) higher midday F{sub NEE} (OG F{sub NEE} = -9.0 {micro}mol m{sup -2} s{sup -1}; ES F{sub NEE} = -7.3 {micro}mol m{sup -2} s{sup -1}) and higher Bowen ratios (OG {beta} = 2.0. ES {beta} = 1.2) at the old-growth forest than at the ES sites during the summer months (May-August). Eddy covariance studies such as ours

  15. Prolonged suppression of ecosystem carbon dioxide uptake after an anomalously warm year.

    PubMed

    Arnone, John A; Verburg, Paul S J; Johnson, Dale W; Larsen, Jessica D; Jasoni, Richard L; Lucchesi, Annmarie J; Batts, Candace M; von Nagy, Christopher; Coulombe, William G; Schorran, David E; Buck, Paul E; Braswell, Bobby H; Coleman, James S; Sherry, Rebecca A; Wallace, Linda L; Luo, Yiqi; Schimel, David S

    2008-09-18

    Terrestrial ecosystems control carbon dioxide fluxes to and from the atmosphere through photosynthesis and respiration, a balance between net primary productivity and heterotrophic respiration, that determines whether an ecosystem is sequestering carbon or releasing it to the atmosphere. Global and site-specific data sets have demonstrated that climate and climate variability influence biogeochemical processes that determine net ecosystem carbon dioxide exchange (NEE) at multiple timescales. Experimental data necessary to quantify impacts of a single climate variable, such as temperature anomalies, on NEE and carbon sequestration of ecosystems at interannual timescales have been lacking. This derives from an inability of field studies to avoid the confounding effects of natural intra-annual and interannual variability in temperature and precipitation. Here we present results from a four-year study using replicate 12,000-kg intact tallgrass prairie monoliths located in four 184-m(3) enclosed lysimeters. We exposed 6 of 12 monoliths to an anomalously warm year in the second year of the study and continuously quantified rates of ecosystem processes, including NEE. We find that warming decreases NEE in both the extreme year and the following year by inducing drought that suppresses net primary productivity in the extreme year and by stimulating heterotrophic respiration of soil biota in the subsequent year. Our data indicate that two years are required for NEE in the previously warmed experimental ecosystems to recover to levels measured in the control ecosystems. This time lag caused net ecosystem carbon sequestration in previously warmed ecosystems to be decreased threefold over the study period, compared with control ecosystems. Our findings suggest that more frequent anomalously warm years, a possible consequence of increasing anthropogenic carbon dioxide levels, may lead to a sustained decrease in carbon dioxide uptake by terrestrial ecosystems.

  16. Using Airborne Microwave Remotely Sensed Root-Zone Soil Moisture and Flux Measurements to Improve Regional Predictions of Carbon Fluxes in a Terrestrial Biosphere Model

    NASA Astrophysics Data System (ADS)

    Zhang, K.; Antonarakis, A. S.; Medvigy, D.; Burgin, M. S.; Crow, W. T.; Milak, S.; Jaruwatanadilok, S.; Truong-Loi, M.; Moghaddam, M.; Saatchi, S. S.; Cuenca, R. H.; Moorcroft, P. R.

    2013-12-01

    North American ecosystems are critical components of the global carbon cycle, exchanging large amounts of carbon dioxide and other gases with the atmosphere. Net ecosystem exchange (NEE) of CO2 between atmosphere and ecosystems quantifies these carbon fluxes, but current continental-scale estimates contain high levels of uncertainty. Root-zone soil moisture (RZSM) and its spatial and temporal heterogeneity influences NEE and improved estimates can help reduce uncertainty in NEE estimates. We used the RZSM measurements from the Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS) mission, and the carbon, water and energy fluxes observed by the eddy-covariance flux towers to constrain the Ecosystem Demography Model 2.2 (ED2.2) to improve its predictions of carbon fluxes. The parameters of the ED2.2 model were first optimized at seven flux tower sites in North America, which represent six different biomes, by constraining the model against a suite of flux measurements and forest inventory measurements through a Bayesian Markov-Chain Monte Carlo framework. We further applied the AirMOSS RZSM products to constrain the ED2.2 model to achieve better estimates of regional NEE. Evaluation against flux tower measurements and forest dynamics measurements shows that the constrained ED2.2 model produces improved predictions of monthly to annual carbon fluxes. The remote sensing based RZSM can further help improve the spatial patterns and temporal variations of model NEE. The results demonstrate that model-data fusion can substantially improve model performance and highlight the important role of RZSM in regulating the spatial and temporal heterogeneities of carbon fluxes.

  17. Seasonal Carbon Dioxide Exchange of a Grazed Grassland in California

    NASA Astrophysics Data System (ADS)

    Xu, L.; Baldocchi, D. D.

    2001-12-01

    An new Ameriflux site was established in late 2000 to study the exchange of carbon dioxide over an oak/grass savanna and a nearby grazed grassland at the foothill of Sierra Nevada in California. Only data from the grazed grassland will be presented here. The flux measurement, along with measurements of meteorological and soil parameters, were start at the end of October 2000. Results from almost one year's data indicated that most of variance of the CO2 flux can be explained by changes in soil water content and leaf area index (LAI). The grass started to growth around middle of October after receiving substantial rainfall. Midday net ecosystem CO2 exchange (NEE) increased slowly from near zero in early November to about -10 μ mol m-2 s-1 (downward flux is negative) in the middle of March. While the nighttime NEE was around 1 to 3 μ mol m-2 s-1. In the spring, there was a peak growth period when photosynthesis and respiration both accelerated. The maximum LAI was 2.0, reached at this peak period. Midday NEE reached a maximum value of -18 μ mol m-2 s-1, and averaged nighttime NEE ranged from 2 to 5 μ mol m-2 s-1. Then as the soil dried out in the early summer, both daytime photosynthesis and night respiration plummeted to near zero. In the dry summer, small value of soil CO2 efflux during daytime only was observed. From almost one season's data, we found that nighttime ecosystem respiration followed closely to the daytime photosynthetic rate, indicating the importance of photosynthetic assimilates allocation for respiration. Annual integrated carbon exchange over this grazed grassland was estimated to be around -120 g C m-2. Results also show that the seasonality of NEE and growth of grasses are quite different from those mid-western grasslands.

  18. Separating the influence of temperature, drought, and fire on interannual variability in atmospheric CO2

    PubMed Central

    Keppel-Aleks, Gretchen; Wolf, Aaron S; Mu, Mingquan; Doney, Scott C; Morton, Douglas C; Kasibhatla, Prasad S; Miller, John B; Dlugokencky, Edward J; Randerson, James T

    2014-01-01

    The response of the carbon cycle in prognostic Earth system models (ESMs) contributes significant uncertainty to projections of global climate change. Quantifying contributions of known drivers of interannual variability in the growth rate of atmospheric carbon dioxide (CO2) is important for improving the representation of terrestrial ecosystem processes in these ESMs. Several recent studies have identified the temperature dependence of tropical net ecosystem exchange (NEE) as a primary driver of this variability by analyzing a single, globally averaged time series of CO2 anomalies. Here we examined how the temporal evolution of CO2 in different latitude bands may be used to separate contributions from temperature stress, drought stress, and fire emissions to CO2 variability. We developed atmospheric CO2 patterns from each of these mechanisms during 1997–2011 using an atmospheric transport model. NEE responses to temperature, NEE responses to drought, and fire emissions all contributed significantly to CO2 variability in each latitude band, suggesting that no single mechanism was the dominant driver. We found that the sum of drought and fire contributions to CO2 variability exceeded direct NEE responses to temperature in both the Northern and Southern Hemispheres. Additional sensitivity tests revealed that these contributions are masked by temporal and spatial smoothing of CO2 observations. Accounting for fires, the sensitivity of tropical NEE to temperature stress decreased by 25% to 2.9 ± 0.4 Pg C yr−1 K−1. These results underscore the need for accurate attribution of the drivers of CO2 variability prior to using contemporary observations to constrain long-term ESM responses. PMID:26074665

  19. Contrasting responses of growing season ecosystem CO2 exchange to variation in temperature and water table depth in two peatlands in northern Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Adkinson, Angela C.; Syed, Kamran H.; Flanagan, Lawrence B.

    2011-03-01

    The large belowground carbon stocks in northern peatland ecosystems are potentially susceptible to release because of the expected differential responses of photosynthesis and respiration to climate change. This study compared net ecosystem CO2 exchange (NEE) measured using the eddy covariance technique at two peatland sites in northern Alberta, Canada, over three growing seasons (May-October). We observed distinct differences between the poor fen (Sphagnum moss dominated) and extreme-rich fen (Carex sedge dominated) sites for their responses of NEE to interannual variation in temperature and water table depth. The rates of growing season cumulative NEE at the poor fen were very similar among the three study years with an average (± standard deviation) of -110.1 ± 0.5 g C m-2 period-1. By contrast, the growing season cumulative NEE at the extreme-rich fen varied substantially among years (-34.5, -153.5, and -41.8 g C m-2 period-1 in 2004, 2005, and 2006, respectively), and net uptake of CO2 was lower (on average) than at the poor fen. Consistent with the eddy covariance measurements, analysis of 210Pb-dated peat cores also showed higher recent net rates of carbon accumulation in the poor fen than in the rich fen. Warm spring temperatures and sufficient water availability during the growing season resulted in the highest-magnitude ecosystem photosynthesis and NEE at the extreme-rich fen in 2005. Cool spring temperatures limited photosynthesis at the extreme-rich fen in 2004, while reduced water availability (lower water table) in 2006 constrained photosynthetic capacity relative to 2005, despite the warmer spring and summer temperatures in 2006. The combination of contrasting plant functional types and different peat water table features at our two study sites meant that the poor fen showed a reduced response of ecosystem CO2 exchange to environmental variation compared to the extreme-rich fen.

  20. Ecosystem CO2/H2O fluxes are explained by hydraulically limited gas exchange during tree mortality from spruce bark beetles

    NASA Astrophysics Data System (ADS)

    Frank, John M.; Massman, William J.; Ewers, Brent E.; Huckaby, Laurie S.; Negrón, José F.

    2014-06-01

    Disturbances are increasing globally due to anthropogenic changes in land use and climate. This study determines whether a disturbance that affects the physiology of individual trees can be used to predict the response of the ecosystem by weighing two competing hypothesis at annual time scales: (a) changes in ecosystem fluxes are proportional to observable patterns of mortality or (b) to explain ecosystem fluxes the physiology of dying trees must also be incorporated. We evaluate these hypotheses by analyzing 6 years of eddy covariance flux data collected throughout the progression of a spruce beetle (Dendroctonus rufipennis) epidemic in a Wyoming Engelmann spruce (Picea engelmannii)-subalpine fir (Abies lasiocarpa) forest and testing for changes in canopy conductance (gc), evapotranspiration (ET), and net ecosystem exchange (NEE) of CO2. We predict from these hypotheses that (a) gc, ET, and NEE all diminish (decrease in absolute magnitude) as trees die or (b) that (1) gc and ET decline as trees are attacked (hydraulic failure from beetle-associated blue-stain fungi) and (2) NEE diminishes both as trees are attacked (restricted gas exchange) and when they die. Ecosystem fluxes declined as the outbreak progressed and the epidemic was best described as two phases: (I) hydraulic failure caused restricted gc, ET (28 ± 4% decline, Bayesian posterior mean ± standard deviation), and gas exchange (NEE diminished 13 ± 6%) and (II) trees died (NEE diminished 51 ± 3% with minimal further change in ET to 36 ± 4%). These results support hypothesis b and suggest that model predictions of ecosystem fluxes following massive disturbances must be modified to account for changes in tree physiological controls and not simply observed mortality.

  1. Seasonal effects of irrigation on land-atmosphere latent heat, sensible heat, and carbon fluxes in semiarid basin

    NASA Astrophysics Data System (ADS)

    Zeng, Yujin; Xie, Zhenghui; Liu, Shuang

    2017-02-01

    Irrigation, which constitutes ˜ 70 % of the total amount of freshwater consumed by the human population, is significantly impacting land-atmosphere fluxes. In this study, using the improved Community Land Model version 4.5 (CLM4.5) with an active crop model, two high-resolution (˜ 1 km) simulations investigating the effects of irrigation on latent heat (LH), sensible heat (SH), and carbon fluxes (or net ecosystem exchange, NEE) from land to atmosphere in the Heihe River basin in northwestern China were conducted using a high-quality irrigation dataset compiled from 1981 to 2013. The model output and measurements from remote sensing demonstrated the capacity of the developed models to reproduce ecological and hydrological processes. The results revealed that the effects of irrigation on LH and SH are strongest during summer, with a LH increase of ˜ 100 W m-2 and a SH decrease of ˜ 60 W m-2 over intensely irrigated areas. However, the reactions are much weaker during spring and autumn when there is much less irrigation. When the irrigation rate is below 5 mm day-1, the LH generally increases, whereas the SH decreases with growing irrigation rates. However, when the irrigation threshold is in excess of 5 mm day-1, there is no accrued effect of irrigation on the LH and SH. Irrigation produces opposite effects to the NEE during spring and summer. During the spring, irrigation yields more discharged carbon from the land to the atmosphere, increasing the NEE value by 0.4-0.8 gC m-2 day-1, while the summer irrigation favors crop fixing of carbon from atmospheric CO2, decreasing the NEE value by ˜ 0.8 gC m-2 day-1. The repercussions of irrigation on land-atmosphere fluxes are not solely linked to the irrigation amount, and other parameters (especially the temperature) also control the effects of irrigation on LH, SH, and NEE.

  2. Carbon and energy fluxes in cropland ecosystems: a model-data comparison

    USGS Publications Warehouse

    Lokupitiya, E.; Denning, A.S.; Schaefer, K.; Ricciuto, D.; Anderson, R.; Arain, M. A.; Baker, I.; Barr, A. G.; Chen, G.; Chen, J.M.; Ciais, P.; Cook, D.R.; Dietze, M.C.; El Maayar, M.; Fischer, M.; Grant, R.; Hollinger, D.; Izaurralde, C.; Jain, A.; Kucharik, C.J.; Li, Z.; Liu, S.; Li, L.; Matamala, R.; Peylin, P.; Price, D.; Running, S. W.; Sahoo, A.; Sprintsin, M.; Suyker, A.E.; Tian, H.; Tonitto, C.; Torn, M.S.; Verbeeck, Hans; Verma, S.B.; Xue, Y.

    2016-01-01

    Croplands are highly productive ecosystems that contribute to land–atmosphere exchange of carbon, energy, and water during their short growing seasons. We evaluated and compared net ecosystem exchange (NEE), latent heat flux (LE), and sensible heat flux (H) simulated by a suite of ecosystem models at five agricultural eddy covariance flux tower sites in the central United States as part of the North American Carbon Program Site Synthesis project. Most of the models overestimated H and underestimated LE during the growing season, leading to overall higher Bowen ratios compared to the observations. Most models systematically under predicted NEE, especially at rain-fed sites. Certain crop-specific models that were developed considering the high productivity and associated physiological changes in specific crops better predicted the NEE and LE at both rain-fed and irrigated sites. Models with specific parameterization for different crops better simulated the inter-annual variability of NEE for maize-soybean rotation compared to those models with a single generic crop type. Stratification according to basic model formulation and phenological methodology did not explain significant variation in model performance across these sites and crops. The under prediction of NEE and LE and over prediction of H by most of the models suggests that models developed and parameterized for natural ecosystems cannot accurately predict the more robust physiology of highly bred and intensively managed crop ecosystems. When coupled in Earth System Models, it is likely that the excessive physiological stress simulated in many land surface component models leads to overestimation of temperature and atmospheric boundary layer depth, and underestimation of humidity and CO2 seasonal uptake over agricultural regions.

  3. Effects of rodent-induced land degradation on ecosystem carbon fluxes in an alpine meadow in the Qinghai-Tibet Plateau, China

    NASA Astrophysics Data System (ADS)

    Peng, F.; Quangang, Y.; Xue, X.; Guo, J.; Wang, T.

    2015-03-01

    The widespread land degradation in an alpine meadow ecosystem would affect ecosystem carbon (C) balance. Biomass, soil chemical properties and carbon dioxide (CO2) of six levels of degraded lands (D1-D6, according to the number of rodent holes and coverage) were investigated to examine the effects of rodent-induced land degradation on an alpine meadow ecosystem. Soil organic carbon (SOC), labile soil carbon (LC), total nitrogen (TN) and inorganic nitrogen (N) were obtained by chemical analysis. Soil respiration (Rs), net ecosystem exchange (NEE) and ecosystem respiration (ER) were measured by a Li-Cor 6400XT. Gross ecosystem production (GEP) was the sum of NEE and ER. Aboveground biomass (AGB) was based on a linear regression with coverage and plant height as independent variables. Root biomass (RB) was obtained by using a core method. Soil respiration, ER, GEP and AGB were significantly higher in slightly degraded (D3 and D6, group I) than in severely degraded land (D1, D2, D4 and D5, group II). Positive values of NEE average indicate that the alpine meadow ecosystem is a weak C sink during the growing season. The only significant difference was in ER among different degradation levels. Rs, ER and GEP were 38.2, 44.3 and 46.5% higher in group I than in group II, respectively. Similar difference of ER and GEP between the two groups resulted in an insignificant difference of NEE. Positive correlations of AGB with ER, NEE and GEP, and relatively small AGB and lower CO2 fluxes in group II, suggest the control of AGB on ecosystem CO2 fluxes. Correlations of RB with SOC, LC, TN and inorganic N indicate the regulation of RB on soil C and N with increasing number of rodent holes in an alpine meadow ecosystem in the permafrost region of the Qinghai-Tibet Plateau (QTP).

  4. Biophysical Controls on Light Response of Net CO2 Exchange in a Winter Wheat Field in the North China Plain

    PubMed Central

    Tong, Xiaojuan; Li, Jun; Yu, Qiang; Lin, Zhonghui

    2014-01-01

    To investigate the impacts of biophysical factors on light response of net ecosystem exchange (NEE), CO2 flux was measured using the eddy covariance technique in a winter wheat field in the North China Plain from 2003 to 2006. A rectangular hyperbolic function was used to describe NEE light response. Maximum photosynthetic capacity (Pmax) was 46.6±4.0 µmol CO2 m−2 s−1 and initial light use efficiency (α) 0.059±0.006 µmol µmol−1 in April−May, two or three times as high as those in March. Stepwise multiple linear regressions showed that Pmax increased with the increase in leaf area index (LAI), canopy conductance (gc) and air temperature (Ta) but declined with increasing vapor pressure deficit (VPD) (P<0.001). The factors influencing Pmax were sorted as LAI, gc, Ta and VPD. α was proportional to ln(LAI), gc, Ta and VPD (P<0.001). The effects of LAI, gc and Ta on α were larger than that of VPD. When Ta>25°C or VPD>1.1−1.3 kPa, NEE residual increased with the increase in Ta and VPD (P<0.001), indicating that temperature and water stress occurred. When gc was more than 14 mm s−1 in March and May and 26 mm s−1 in April, the NEE residuals decline disappeared, or even turned into an increase in gc (P<0.01), implying shifts from stomatal limitation to non-stomatal limitation on NEE. Although the differences between sunny and cloudy sky conditions were unremarkable for light response parameters, simulated net CO2 uptake under the same radiation intensity averaged 18% higher in cloudy days than in sunny days during the year 2003−2006. It is necessary to include these effects in relevant carbon cycle models to improve our estimation of carbon balance at regional and global scales. PMID:24586800

  5. Cyclic occurrence of fire and its role in carbon dynamics along an edaphic moisture gradient in longleaf pine ecosystems.

    PubMed

    Whelan, Andrew; Mitchell, Robert; Staudhammer, Christina; Starr, Gregory

    2013-01-01

    Fire regulates the structure and function of savanna ecosystems, yet we lack understanding of how cyclic fire affects savanna carbon dynamics. Furthermore, it is largely unknown how predicted changes in climate may impact the interaction between fire and carbon cycling in these ecosystems. This study utilizes a novel combination of prescribed fire, eddy covariance (EC) and statistical techniques to investigate carbon dynamics in frequently burned longleaf pine savannas along a gradient of soil moisture availability (mesic, intermediate and xeric). This research approach allowed us to investigate the complex interactions between carbon exchange and cyclic fire along the ecological amplitude of longleaf pine. Over three years of EC measurement of net ecosystem exchange (NEE) show that the mesic site was a net carbon sink (NEE = -2.48 tonnes C ha(-1)), while intermediate and xeric sites were net carbon sources (NEE = 1.57 and 1.46 tonnes C ha(-1), respectively), but when carbon losses due to fuel consumption were taken into account, all three sites were carbon sources (10.78, 7.95 and 9.69 tonnes C ha(-1) at the mesic, intermediate and xeric sites, respectively). Nonetheless, rates of NEE returned to pre-fire levels 1-2 months following fire. Consumption of leaf area by prescribed fire was associated with reduction in NEE post-fire, and the system quickly recovered its carbon uptake capacity 30-60 days post fire. While losses due to fire affected carbon balances on short time scales (instantaneous to a few months), drought conditions over the final two years of the study were a more important driver of net carbon loss on yearly to multi-year time scales. However, longer-term observations over greater environmental variability and additional fire cycles would help to more precisely examine interactions between fire and climate and make future predictions about carbon dynamics in these systems.

  6. Does Terrestrial Drought Explain Global CO2 Flux Anomalies Induced by El Nino?

    NASA Technical Reports Server (NTRS)

    Schwalm. C. R.; Williams, C. A.; Schaefer, K.; Baker, I.; Collatz, G. J.; Roedenbeck, C.

    2011-01-01

    The El Nino Southern Oscillation is the dominant year-to-year mode of global climate variability. El Nino effects on terrestrial carbon cycling are mediated by associated climate anomalies, primarily drought, influencing fire emissions and biotic net ecosystem exchange (NEE). Here we evaluate whether El Nino produces a consistent response from the global carbon cycle. We apply a novel bottom-up approach to estimating global NEE anomalies based on FLUXNET data using land cover maps and weather reanalysis. We analyze 13 years (1997-2009) of globally gridded observational NEE anomalies derived from eddy covariance flux data, remotely-sensed fire emissions at the monthly time step, and NEE estimated from an atmospheric transport inversion. We evaluate the overall consistency of biospheric response to El Nino and, more generally, the link between global CO2 flux anomalies and El Nino-induced drought. Our findings, which are robust relative to uncertainty in both methods and time-lags in response, indicate that each event has a different spatial signature with only limited spatial coherence in Amazonia, Australia and southern Africa. For most regions, the sign of response changed across El Nino events. Biotic NEE anomalies, across 5 El Nino events, ranged from -1.34 to +0.98 Pg Cyr(exp -1, whereas fire emissions anomalies were generally smaller in magnitude (ranging from -0.49 to +0.53 Pg C yr(exp -1). Overall drought does not appear to impose consistent terrestrial CO2 flux anomalies during El Ninos, finding large variation in globally integrated responses from 11.15 to +0.49 Pg Cyr(exp -1). Despite the significant correlation between the CO2 flux and El Nino indices, we find that El Nino events have, when globally integrated, both enhanced and weakened terrestrial sink strength, with no consistent response across events

  7. Diurnal and seasonal variations of CO2 fluxes and their climate controlling factors for a subtropical forest in Ningxiang

    NASA Astrophysics Data System (ADS)

    Jia, Binghao; Xie, Zhenghui; Zeng, Yujin; Wang, Linying; Wang, Yuanyuan; Xie, Jinbo; Xie, Zhipeng

    2015-04-01

    In this study, the diurnal and seasonal variations of CO2 fluxes in a subtropical mixed evergreen forest in Ningxiang of Hunan Province, part of the East Asian monsoon region, were quantified for the first time. The fluxes were based on eddy covariance measurements from a newly initiated flux tower. The relationship between the CO2 fluxes and climate factors was also analyzed. The results showed that the target ecosystem appeared to be a clear carbon sink in 2013, with integrated net ecosystem CO2 exchange (NEE), ecosystem respiration (RE), and gross ecosystem productivity (GEP) of -428.8, 1534.8 and 1963.6 g C m-2yr-1, respectively. The net carbon uptake (i.e. the -NEE), RE and GEP showed obvious seasonal variability, and were lower in winter and under drought conditions and higher in the growing season. The minimum NEE occurred on 12 June (-7.4 g C m-2 d-1), due mainly to strong radiation, adequate moisture, and moderate temperature; while a very low net CO2 uptake occurred in August (9 g C m-2 month-1), attributable to extreme summer drought. In addition, the NEE and GEP showed obvious diurnal variability that changed with the seasons. In winter, solar radiation and temperature were the main controlling factors for GEP, while the soil water content and vapor pressure deficit were the controlling factors in summer. Furthermore, the daytime NEE was mainly limited by the water-stress effect under dry and warm atmospheric conditions, rather than by the direct temperature-stress effect.

  8. Land use affects the net ecosystem CO(2) exchange and its components in mountain grasslands.

    PubMed

    Schmitt, M; Bahn, M; Wohlfahrt, G; Tappeiner, U; Cernusca, A

    2010-08-01

    Changes in land use and management have been strongly affecting mountain grassland, however, their effects on the net ecosystem exchange of CO(2) (NEE) and its components have not yet been well documented. We analysed chamber-based estimates of NEE, gross primary productivity (GPP), ecosystem respiration (R) and light use efficiency (LUE) of six mountain grasslands differing in land use and management, and thus site fertility, for the growing seasons of 2002 to 2008. The main findings of the study are that: (1) land use and management affected seasonal NEE, GPP and R, which all decreased from managed to unmanaged grasslands; (2) these changes were explained by differences in leaf area index (LAI), biomass and leaf-area-independent changes that were likely related to photosynthetic physiology; (3) diurnal variations of NEE were primarily controlled by photosynthetically active photon flux density and soil and air temperature; seasonal variations were associated with changes in LAI; (4) parameters of light response curves were generally closely related to each other, and the ratio of R at a reference temperature/ maximum GPP was nearly constant across the sites; (5) similarly to our study, maximum GPP and R for other grasslands on the globe decreased with decreasing land use intensity, while their ratio remained remarkably constant. We conclude that decreasing intensity of management and, in particular, abandonment of mountain grassland lead to a decrease in NEE and its component processes. While GPP and R are generally closely coupled during most of the growing season, GPP is more immediately and strongly affected by land management (mowing, grazing) and season. This suggests that management and growing season length, as well as their possible future changes, may play an important role for the annual C balance of mountain grassland.

  9. Nonlinear CO2 flux response to 7 years of experimentally induced permafrost thaw.

    PubMed

    Mauritz, Marguerite; Bracho, Rosvel; Celis, Gerardo; Hutchings, Jack; Natali, Susan M; Pegoraro, Elaine; Salmon, Verity G; Schädel, Christina; Webb, Elizabeth E; Schuur, Edward A G

    2017-02-16

    Rapid Arctic warming is expected to increase global greenhouse gas concentrations as permafrost thaw exposes immense stores of frozen carbon (C) to microbial decomposition. Permafrost thaw also stimulates plant growth, which could offset C loss. Using data from 7 years of experimental Air and Soil warming in moist acidic tundra, we show that Soil warming had a much stronger effect on CO2 flux than Air warming. Soil warming caused rapid permafrost thaw and increased ecosystem respiration (Reco ), gross primary productivity (GPP), and net summer CO2 storage (NEE). Over 7 years Reco , GPP, and NEE also increased in Control (i.e., ambient plots), but this change could be explained by slow thaw in Control areas. In the initial stages of thaw, Reco , GPP, and NEE increased linearly with thaw across all treatments, despite different rates of thaw. As thaw in Soil warming continued to increase linearly, ground surface subsidence created saturated microsites and suppressed Reco , GPP, and NEE. However Reco and GPP remained high in areas with large Eriophorum vaginatum biomass. In general NEE increased with thaw, but was more strongly correlated with plant biomass than thaw, indicating that higher Reco in deeply thawed areas during summer months was balanced by GPP. Summer CO2 flux across treatments fit a single quadratic relationship that captured the functional response of CO2 flux to thaw, water table depth, and plant biomass. These results demonstrate the importance of indirect thaw effects on CO2 flux: plant growth and water table dynamics. Nonsummer Reco models estimated that the area was an annual CO2 source during all years of observation. Nonsummer CO2 loss in warmer, more deeply thawed soils exceeded the increases in summer GPP, and thawed tundra was a net annual CO2 source.

  10. Detecting Disturbance and its Impact on Ecosystem Carbon Balance from Global to Regional Scales

    NASA Astrophysics Data System (ADS)

    Ballantyne, A.; Jacobson, A. R.; Anderegg, W.; Poulter, B.; Cooper, L. A.; Smith, W. K.; Miller, J. B.

    2015-12-01

    One of the most vital ecosystem services currently provided by the terrestrial biosphere is the removal of approximately one quarter of the anthropogenic CO2 emitted to the atmosphere. However, as patterns of temperature and precipitation change so is the frequency and intensity of ecosystem disturbance. Despite evidence that ecosystem disturbance regimes have shifted leading to widespread forest mortality, the net effect of disturbance on the carbon (C) balance of forest ecosystems remains uncertain. We will use satellite and atmospheric observations to deconvolve net carbon exchange (NEE) into its component fluxes of gross primary productivity and total respiration (e.g. NEE= GPP - R) at global to regional scales. At the global scale we find that NEE has increased over the last 50 years and appears to have accelerated as a result of diminished R over the last 15 years. However the variance in global NEE has also increased perhaps due to inter-annual variability in R, especially within semi-arid ecosystems. These global trends are not necessarily consistent with regional patterns in the net carbon balance, especially across the western US. Atmospheric mass balance suggests that ecosystems of North America have shifted from a net C sink to a net C source. While prolonged drought across the Western US has likely caused this shift in continental scale NEE, attributing this shift in the net C balance to any one mechanism of disturbance (e.g. drought, insect infestation, and fire) or their interactions is challenging. Lastly, we will evaluate existing observing networks, such as NOAA/ESRL and Ameriflux, and how they can be combined with nascent networks, such as NEON, EarthNetworks, and OCO-2, to identify regional disturbance processes that may be causing increasing variance in the global C cycle.

  11. New data-driven estimation of terrestrial CO2 fluxes in Asia using a standardized database of eddy covariance measurements, remote sensing data, and support vector regression

    NASA Astrophysics Data System (ADS)

    Ichii, Kazuhito; Ueyama, Masahito; Kondo, Masayuki; Saigusa, Nobuko; Kim, Joon; Alberto, Ma. Carmelita; Ardö, Jonas; Euskirchen, Eugénie S.; Kang, Minseok; Hirano, Takashi; Joiner, Joanna; Kobayashi, Hideki; Marchesini, Luca Belelli; Merbold, Lutz; Miyata, Akira; Saitoh, Taku M.; Takagi, Kentaro; Varlagin, Andrej; Bret-Harte, M. Syndonia; Kitamura, Kenzo; Kosugi, Yoshiko; Kotani, Ayumi; Kumar, Kireet; Li, Sheng-Gong; Machimura, Takashi; Matsuura, Yojiro; Mizoguchi, Yasuko; Ohta, Takeshi; Mukherjee, Sandipan; Yanagi, Yuji; Yasuda, Yukio; Zhang, Yiping; Zhao, Fenghua

    2017-04-01

    The lack of a standardized database of eddy covariance observations has been an obstacle for data-driven estimation of terrestrial CO2 fluxes in Asia. In this study, we developed such a standardized database using 54 sites from various databases by applying consistent postprocessing for data-driven estimation of gross primary productivity (GPP) and net ecosystem CO2 exchange (NEE). Data-driven estimation was conducted by using a machine learning algorithm: support vector regression (SVR), with remote sensing data for 2000 to 2015 period. Site-level evaluation of the estimated CO2 fluxes shows that although performance varies in different vegetation and climate classifications, GPP and NEE at 8 days are reproduced (e.g., r2 = 0.73 and 0.42 for 8 day GPP and NEE). Evaluation of spatially estimated GPP with Global Ozone Monitoring Experiment 2 sensor-based Sun-induced chlorophyll fluorescence shows that monthly GPP variations at subcontinental scale were reproduced by SVR (r2 = 1.00, 0.94, 0.91, and 0.89 for Siberia, East Asia, South Asia, and Southeast Asia, respectively). Evaluation of spatially estimated NEE with net atmosphere-land CO2 fluxes of Greenhouse Gases Observing Satellite (GOSAT) Level 4A product shows that monthly variations of these data were consistent in Siberia and East Asia; meanwhile, inconsistency was found in South Asia and Southeast Asia. Furthermore, differences in the land CO2 fluxes from SVR-NEE and GOSAT Level 4A were partially explained by accounting for the differences in the definition of land CO2 fluxes. These data-driven estimates can provide a new opportunity to assess CO2 fluxes in Asia and evaluate and constrain terrestrial ecosystem models.

  12. Nonlinear CO2 flux response to 7 years of experimentally induced permafrost thaw

    DOE PAGES

    Mauritz, Marguerite; Bracho, Rosvel; Celis, Gerardo; ...

    2017-02-16

    Rapid Arctic warming is expected to increase global greenhouse gas concentrations as permafrost thaw exposes immense stores of frozen carbon (C) to microbial decomposition. Permafrost thaw also stimulates plant growth, which could offset C loss. Using data from 7 years of experimental Air and Soil warming in moist acidic tundra, we show that Soil warming had a much stronger effect on CO2 flux than Air warming. Soil warming caused rapid permafrost thaw and increased ecosystem respiration (Reco), gross primary productivity (GPP), and net summer CO2 storage (NEE). Over 7 years Reco, GPP, and NEE also increased in Control (i.e., ambientmore » plots), but this change could be explained by slow thaw in Control areas. In the initial stages of thaw, Reco, GPP, and NEE increased linearly with thaw across all treatments, despite different rates of thaw. As thaw in Soil warming continued to increase linearly, ground surface subsidence created saturated microsites and suppressed Reco, GPP, and NEE. However Reco and GPP remained high in areas with large Eriophorum vaginatum biomass. In general NEE increased with thaw, but was more strongly correlated with plant biomass than thaw, indicating that higher Reco in deeply thawed areas during summer months was balanced by GPP. Summer CO2 flux across treatments fit a single quadratic relationship that captured the functional response of CO2 flux to thaw, water table depth, and plant biomass. These results demonstrate the importance of indirect thaw effects on CO2 flux: plant growth and water table dynamics. Nonsummer Reco models estimated that the area was an annual CO2 source during all years of observation. As a result, nonsummer CO2 loss in warmer, more deeply thawed soils exceeded the increases in summer GPP, and thawed tundra was a net annual CO2 source.« less

  13. Evaluate the seasonal cycle and interannual variability of carbon fluxes and the associated uncertainties using modeled and observed data

    NASA Astrophysics Data System (ADS)

    Zeng, F.; Collatz, G. J.; Ivanoff, A.

    2013-12-01

    We assessed the performance of the Carnegie-Ames-Stanford Approach - Global Fire Emissions Database (CASA-GFED3) terrestrial carbon cycle model in simulating seasonal cycle and interannual variability (IAV) of global and regional carbon fluxes and uncertainties associated with model parameterization. Key model parameters were identified from sensitivity analyses and their uncertainties were propagated through model processes using the Monte Carlo approach to estimate the uncertainties in carbon fluxes and pool sizes. Three independent flux data sets, the global gross primary productivity (GPP) upscaled from eddy covariance flux measurements by Jung et al. (2011), the net ecosystem exchange (NEE) estimated by CarbonTracker, and the eddy covariance flux observations, were used to evaluate modeled fluxes and the uncertainties. Modeled fluxes agree well with both Jung's GPP and CarbonTracker NEE in the amplitude and phase of seasonal cycle, except in the case of GPP in tropical regions where Jung et al. (2011) showed larger fluxes and seasonal amplitude. Modeled GPP IAV is positively correlated (p < 0.1) with Jung's GPP IAV except in the tropics and temperate South America. The correlations between modeled NEE IAV and CarbonTracker NEE IAV are weak at regional to continental scales but stronger when fluxes are aggregated to >40°N latitude. At regional to continental scales flux uncertainties were larger than the IAV in the fluxes for both Jung's GPP and CarbonTracker NEE. Comparisons with eddy covariance flux observations are focused on sites within regions and years of recorded large-scale climate anomalies. We also evaluated modeled biomass using other independent continental biomass estimates and found good agreement. From the comparisons we identify the strengths and weaknesses of the model to capture the seasonal cycle and IAV of carbon fluxes and highlight ways to improve model performance.

  14. Competition is constitutional: Four fallacies in the argument that transmission access constitutes a taking

    SciTech Connect

    Schotland, S.D.

    1996-11-01

    New transmission regulations may cause a change in property value or property access, however, this alone does not constitute a regulatory taking. In an industry with a long history of regulation and some degree of shared transmission access, the utilities are going to be hard pressed to show that recent open access mandates are in violation of the Takings Clause of the Fifth Amendment. In a recent article, John Rowe and Paige Graening of the NEES Companies argued that transmission access is the twentieth century equivalent of {open_quotes}piracy{close_quotes} - forcing utilities to provide transmission access to third parties violates the Taking Clause of the Fifth Amendment. The authors stated that transmission access represents a permanent physical invasion of property - which is unconstitutional without {open_quotes}just compensation.{close_quotes} The same arguments have been raised by Michigan utilities in a pending court challenge to the retail wheeling experiment ordered by the Michigan Public Service Commission. Rowe and Graening complain that {open_quotes}under the Jolly Roger of open competition{close_quotes} regulators will limit utilities to {open_quotes}mere embedded costs,{close_quotes} thereby committing an act of {open_quotes}piracy.{close_quotes} Contrary to Rowe and Graening`s claim, the flag of competition is better represented by the Stars and Stripes, since orders to provide transmission access at the cost of service do not result in a regulatory taking. Four fallacies led NEES down the gangplank: (1) The authors argued that reductions in the value of an investment are necessarily takings. Regulatory impairment of property value is a fact of life. (2) Contrary to NEES, transmission access does not effect a permanent physical invasion of property. (3) NEES claimed that transmission access defeats reasonable investment expectations. (4) NEES relied on case law that affords utilities the opportunity to realize a profit.

  15. Increasing Seasonal CO2 Fluxes and the Potential Role of Changing Plant Functional Types

    NASA Astrophysics Data System (ADS)

    Welp, L. R.; Graven, H. D.; Keeling, R. F.; Piper, S. C.; Patra, P. K.; Roedenbeck, C.

    2014-12-01

    Previous work by Graven et al. (Science, 2013) has shown that the seasonal cycle of CO2 has increased throughout the troposphere by 50% north of 45°N since the 1950s. This suggests large-scale ecological changes centered on the boreal and temperate forests, and a contribution from the Arctic. Graven et al. indicated a comparable 30-50% increase in seasonal net ecosystem exchange (NEE) fluxes is required to explain the observed change in CO2 amplitude. We examine changes in NEE fluxes in boreal and Arctic regions for the period 1986-2012 using two time-varying atmospheric inversions, RIGC and Jena. The inversions show that, over the last few decades, the largest percent increases in seasonal NEE occur between 50-70°N. They also provide evidence that larger summertime uptake is the main driver of CO2 amplitude increases. One way that summer uptake may have increased is by changes in plant functional type (PFT), away from evergreen toward more deciduous forest coverage. Eddy covariance NEE measurements are helpful in determining the seasonality of net CO2 exchange for different PFTs. The seasonal amplitude in net CO2 uptake by deciduous boreal forests can easily be twice as large as for evergreen forests. In this presentation we will explore the relative influence of deciduous and evergreen plant functional types on the seasonal cycle of CO2 using FluxNet data and atmospheric transport modeling, and the potential effect of changing forest composition on CO2 amplitude trends. Understanding the processes affecting the seasonal cycle of NEE fluxes will allow better predictions of the net carbon-uptake or release in this climatically sensitive region.

  16. Separating the influence of temperature, drought, and fire on interannual variability in atmospheric CO2.

    PubMed

    Keppel-Aleks, Gretchen; Wolf, Aaron S; Mu, Mingquan; Doney, Scott C; Morton, Douglas C; Kasibhatla, Prasad S; Miller, John B; Dlugokencky, Edward J; Randerson, James T

    2014-11-01

    The response of the carbon cycle in prognostic Earth system models (ESMs) contributes significant uncertainty to projections of global climate change. Quantifying contributions of known drivers of interannual variability in the growth rate of atmospheric carbon dioxide (CO2) is important for improving the representation of terrestrial ecosystem processes in these ESMs. Several recent studies have identified the temperature dependence of tropical net ecosystem exchange (NEE) as a primary driver of this variability by analyzing a single, globally averaged time series of CO2 anomalies. Here we examined how the temporal evolution of CO2 in different latitude bands may be used to separate contributions from temperature stress, drought stress, and fire emissions to CO2 variability. We developed atmospheric CO2 patterns from each of these mechanisms during 1997-2011 using an atmospheric transport model. NEE responses to temperature, NEE responses to drought, and fire emissions all contributed significantly to CO2 variability in each latitude band, suggesting that no single mechanism was the dominant driver. We found that the sum of drought and fire contributions to CO2 variability exceeded direct NEE responses to temperature in both the Northern and Southern Hemispheres. Additional sensitivity tests revealed that these contributions are masked by temporal and spatial smoothing of CO2 observations. Accounting for fires, the sensitivity of tropical NEE to temperature stress decreased by 25% to 2.9 ± 0.4 Pg C yr(-1) K(-1). These results underscore the need for accurate attribution of the drivers of CO2 variability prior to using contemporary observations to constrain long-term ESM responses.

  17. Evaluation of the DayCent model to predict carbon fluxes in French crop sites

    NASA Astrophysics Data System (ADS)

    Fujisaki, Kenji; Martin, Manuel P.; Zhang, Yao; Bernoux, Martial; Chapuis-Lardy, Lydie

    2017-04-01

    Croplands in temperate regions are an important component of the carbon balance and can act as a sink or a source of carbon, depending on pedoclimatic conditions and management practices. Therefore the evaluation of carbon fluxes in croplands by modelling approach is relevant in the context of global change. This study was part of the Comete-Global project funded by the multi-Partner call FACCE JPI. Carbon fluxes, net ecosystem exchange (NEE), leaf area index (LAI), biomass, and grain production were simulated at the site level in three French crop experiments from the CarboEurope project. Several crops were studied, like winter wheat, rapeseed, barley, maize, and sunflower. Daily NEE was measured with eddy covariance and could be partitioned between gross primary production (GPP) and total ecosystem respiration (TER). Measurements were compared to DayCent simulations, a process-based model predicting plant production and soil organic matter turnover at daily time step. We compared two versions of the model: the original one with a simplified plant module and a newer version that simulates LAI. Input data for modelling were soil properties, climate, and management practices. Simulations of grain yields and biomass production were acceptable when using optimized crop parameters. Simulation of NEE was also acceptable. GPP predictions were improved with the newer version of the model, eliminating temporal shifts that could be observed with the original model. TER was underestimated by the model. Predicted NEE was more sensitive to soil tillage and nitrogen applications than measured NEE. DayCent was therefore a relevant tool to predict carbon fluxes in French crops at the site level. The introduction of LAI in the model improved its performance.

  18. Comparing the carbonyl sulfide (COS) method with two carbon flux based methods of flux partitioning at a freshwater marsh

    NASA Astrophysics Data System (ADS)

    Sun, W.; Maseyk, K. S.; Lett, C.; Pesqueira, A.; Seibt, U.

    2016-12-01

    Carbonyl sulfide (COS) has emerged as a novel photosynthetic tracer for partitioning net ecosystem exchange (NEE), because leaf uptake of COS is coupled to CO2 uptake due to their shared diffusional pathway and similar hydrolytic reactions. At a freshwater marsh site in southern California (AmeriFlux: US-SJ1), we measured COS and CO2 ecosystem fluxes, leaf-scale fluxes, and ground fluxes during the 2013 growing season. Here we compare the COS-based partitioning of NEE with two widely used partitioning methods that rely on carbon flux measurements only: the nighttime respiration method and light response curve method. The measurements covered two distinct periods: one with inundated surface, and the other with drained surface. In the inundated period, ground COS emissions were small ( 4 pmol m-2 s-1) and CO2 emissions were minimal (< 1 µmol m-2 s-1). After the surface water had drained, mean CO2 emission increased by almost an order of magnitude while mean COS emission increased about 20%. The two periods with different ground emissions offer suitable conditions for testing partitioning methods. We calculated canopy COS to CO2 relative uptake ratios by scaling up leaf relative uptake ratios (LRU) using canopy light profiles, and obtained GPP estimates from the net canopy COS uptake. The COS-based GPP estimates are in general consistent with those derived from the light response curve method. In contrast, the nighttime respiration method did not work due to low turbulence conditions and poor correlation between respiration and temperature. Although NEE changed between the inundated and drained periods, GPP estimates from COS measurements and light response curves remained similar, indicating NEE changes were mainly driven by changes in ground emissions consistent with our surface measurements. Our results indicate that the COS method and the light response curve method both perform well in partitioning NEE at this freshwater marsh ecosystem.

  19. Retrieval of average CO2 fluxes by combining in situ CO2 measurements and backscatter lidar information

    NASA Astrophysics Data System (ADS)

    Gibert, Fabien; Schmidt, Martina; Cuesta, Juan; Ciais, Philippe; Ramonet, Michel; Xueref, IrèNe; Larmanou, Eric; Flamant, Pierre Henri

    2007-05-01

    The present paper deals with a boundary layer budgeting method which makes use of observations from various in situ and remote sensing instruments to infer regional average net ecosystem exchange (NEE) of CO2. Measurements of CO2 within and above the atmospheric boundary layer (ABL) by in situ sensors, in conjunction with a precise knowledge of the change in ABL height by lidar and radiosoundings, enable to infer diurnal and seasonal NEE variations. Near-ground in situ CO measurements are used to discriminate natural and anthropogenic contributions of CO2 diurnal variations in the ABL. The method yields mean NEE that amounts to 5 μmol m-2 s-1 during the night and -20 μmol m-2 s-1 in the middle of the day between May and July. A good agreement is found with the expected NEE accounting for a mixed wheat field and forest area during winter season, representative of the mesoscale ecosystems in the Paris area according to the trajectory of an air column crossing the landscape. Daytime NEE is seen to follow the vegetation growth and the change in the ratio diffuse/direct radiation. The CO2 vertical mixing flux during the rise of the atmospheric boundary layer is also estimated and seems to be the main cause of the large decrease of CO2 mixing ratio in the morning. The outcomes on CO2 flux estimate are compared to eddy-covariance measurements on a barley field. The importance of various sources of error and uncertainty on the retrieval is discussed. These errors are estimated to be less than 15%; the main error resulted from anthropogenic emissions.

  20. Climate and Biological Controls of Carbon Fluxes along latitudinal gradients

    NASA Astrophysics Data System (ADS)

    Luo, Y.; Yuan, J.; Niu, S.

    2012-12-01

    It has not been carefully examined whether relative importance of climate and biological controls of carbon fluxes is similar among various ecosystem types along latitudinal gradients from the tropical to polar region. We hypothesize that except tropical regions, there is a consistent pattern of climate and biological controls of carbon fluxes across all the other ecosystems. We tested the hypothesis by analyzing data of net ecosystem exchange (NEE) from nearly 200 eddy-flux towers distributed worldwide and simulated gross primary production (GPP) from the Australian Community Atmosphere Land Exchange (CABLE) model. Specifically, we estimated yearly NEE (i.e., NEP), carbon uptake period (CUP) and seasonal maximum of NEE (NEE¬_max) from eddy-flux data. Similarly, we estimated CUP, GPP_max, seasonal maximum leaf area index (LAI_max), and Vcmax from the model across the globe. Our regression analysis indicates that NEP is very tightly correlated with the product of CUP and NEE_max cross all sites. Similarly, simulated GPP is highly correlated with the product of CUP and GPP_max over the globe in the CABLE model. CUP is related to phenology and represents climate control of carbon fluxes while NEE_max or GPP_max is determined by biological processes and thus represents biological control of carbon processes. We further analyzed relationships of GPP_max with LAI_max and Vcmax individually or in combination. GPP_max is highly correlated with them. This talk will present results of our analysis and explain our hypothesis test regarding relative importance of biological and climate controls of carbon fluxes along the latitudinal gradients.

  1. Carbon dioxide exchange in a semidesert grassland through drought-induced vegetation change

    NASA Astrophysics Data System (ADS)

    Scott, Russell L.; Hamerlynck, Erik P.; Jenerette, G. Darrel; Moran, M. Susan; Barron-Gafford, Greg A.

    2010-09-01

    Global warming may intensify the hydrological cycle and lead to increased drought severity and duration, which could alter plant community structure and subsequent ecosystem water and carbon dioxide cycling. We report on the net ecosystem exchange of carbon dioxide (NEE) of a semidesert grassland through a severe drought which drove succession from native bunchgrasses to forbs and to eventual dominance by an exotic bunchgrass. We monitored NEE and energy fluxes using eddy covariance coupled with meteorological and soil moisture variables for 6 years at a grassland site in southeastern Arizona, USA. Seasonal NEE typically showed a springtime carbon uptake after winter-spring periods of average rainfall followed by much stronger sink activity during the summer rainy season. The two severe drought years (2004 and 2005) resulted in a net release of carbon dioxide (25 g C m-2) and widespread mortality of native perennial bunchgrasses. Above average summer rains in 2006 alleviated drought conditions, resulting in a large flush of broad-leaved forbs and negative total NEE (-55 g C m-2 year-1). Starting in 2007 and continuing through 2009, the ecosystem became increasingly dominated by the exotic grass, Eragrostis lehmanniana, and was a net carbon sink (-47 to -98 g C m-2 year-1) but with distinct annual patterns in NEE. Rainfall mediated by soils was the key driver to water and carbon fluxes. Seasonal respiration and photosynthesis were strongly dependent on precipitation, but photosynthesis was more sensitive to rainfall variation. Respiration normalized by evapotranspiration showed no interannual variation, while normalized gross ecosystem production (i.e., water use efficiency) was low during drought years and then increased as the rains returned and the E. lehmanniana invasion progressed. Thus, when dry summer conditions returned in 2009, the potential for ecosystem carbon accumulation was increased and the ecosystem remained a net sink unlike similar dry years when

  2. Estimating Large-Scale Carbon Fluxes from Remotely-Sensed Biomass and Vegetation Indices

    NASA Astrophysics Data System (ADS)

    Bloom, A. A.; Williams, M. D.

    2012-12-01

    Large uncertainties are associated with net ecosystem exchange (NEE) estimates across continental scales. The assimilation of satellite-derived biometric data into carbon cycle (C) models can lead to an improved understanding of ecosystem C fluxes and ultimately to a reduction of estimated NEE uncertainty. We implement a Monte Carlo model-data fusion approach to assimilate MODIS LAI and GLAS-derived canopy height into the Data Assimilation Linked Ecosystem Carbon (DALEC) model, in order to estimate ecosystem C allocation and the magnitude of C fluxes. In particular, we test a broad reality check in the assimilation cost-function: we discard ``unrealistic'' combinations of randomly sampled allocation parameters and C pool dynamics in DALEC, without discarding non-equilibrium states. We first test our approach on two forested eddy-covariance flux tower sites with well characterised C pools (Hesse, France and Loobos, Netherlands). When assimilating satellite-derived products without reality constraints we are unable to adequately describe NEE and C pool magnitudes. However, when we also implement the reality check we find (a) a >99% reduction in viable parameter combinations (b) significant reductions in NEE and parameter uncertainties (c) a convergence in NEE estimates (r2 = 0.59 -- 0.79, |NEEbias | ≤ 0.44 gC m2 day-1) and (d) strong inter-relationships between C allocation parameters and C pools. We apply this approach on larger spatial scales, and we discuss the sensitivity of our results to uncertainties associated with the assimilated data-streams. We conclude that our approach is an important step in bridging the gap between remotely-sensed biometric data and the full ecosystem C cycle.

  3. Carbon and energy fluxes in cropland ecosystems: a model-data comparison

    SciTech Connect

    Lokupitiya, E.; Denning, A. S.; Schaefer, K.; Ricciuto, D.; Anderson, R.; Arain, M. A.; Baker, I.; Barr, A. G.; Chen, G.; Chen, J. M.; Ciais, P.; Cook, D. R.; Dietze, M.; El Maayar, M.; Fischer, M.; Grant, R.; Hollinger, D.; Izaurralde, C.; Jain, A.; Kucharik, C.; Li, Z.; Liu, S.; Li, L.; Matamala, R.; Peylin, P.; Price, D.; Running, S. W.; Sahoo, A.; Sprintsin, M.; Suyker, A. E.; Tian, H.; Tonitto, C.; Torn, M.; Verbeeck, Hans; Verma, S. B.; Xue, Y.

    2016-06-03

    Croplands are highly productive ecosystems that contribute to land–atmosphere exchange of carbon, energy, and water during their short growing seasons. We evaluated and compared net ecosystem exchange (NEE), latent heat flux (LE), and sensible heat flux (H) simulated by a suite of ecosystem models at five agricultural eddy covariance flux tower sites in the central United States as part of the North American Carbon Program Site Synthesis project. Most of the models overestimated H and underestimated LE during the growing season, leading to overall higher Bowen ratios compared to the observations. Most models systematically under predicted NEE, especially at rain-fed sites. Certain crop-specific models that were developed considering the high productivity and associated physiological changes in specific crops better predicted the NEE and LE at both rain-fed and irrigated sites. Models with specific parameterization for different crops better simulated the inter-annual variability of NEE for maize-soybean rotation compared to those models with a single generic crop type. Stratification according to basic model formulation and phenological methodology did not explain significant variation in model performance across these sites and crops. The under prediction of NEE and LE and over prediction of H by most of the models suggests that models developed and parameterized for natural ecosystems cannot accurately predict the more robust physiology of highly bred and intensively managed crop ecosystems. When coupled in Earth System Models, it is likely that the excessive physiological stress simulated in many land surface component models leads to overestimation of temperature and atmospheric boundary layer depth, and underestimation of humidity and CO2 seasonal uptake over agricultural regions.

  4. The behavior of multiple independent managers and ecological traits interact to determine prevalence of weeds.

    PubMed

    Coutts, Shaun R; Yokomizo, Hiroyuki; Buckley, Yvonne M

    2013-04-01

    Management of damaging invasive plants is often undertaken by multiple decision makers, each managing only a small part of the invader's population. As weeds can move between properties and re-infest eradicated sites from unmanaged sources, the dynamics of multiple decision makers plays a significant role in weed prevalence and invasion risk at the landscape scale. We used a spatially explicit agent-based simulation to determine how individual agent behavior, in concert with weed population ecology, determined weed prevalence. We compared two invasive grass species that differ in ecology, control methods, and costs: Nassella trichotoma (serrated tussock) and Eragrostis curvula (African love grass). The way decision makers reacted to the benefit of management had a large effect on the extent of a weed. If benefits of weed control outweighed the costs, and either net benefit was very large or all agents were very sensitive to net benefits, then agents tended to act synchronously, reducing the pool of infested agents available to spread the weed. As N. trichotoma was more damaging than E. curvula and had more effective control methods, agents chose to manage it more often, which resulted in lower prevalence of N. trichotoma. A relatively low number of agents who were intrinsically less motivated to control weeds led to increased prevalence of both species. This was particularly apparent when long-distance dispersal meant each infested agent increased the invasion risk for a large portion of the landscape. In this case, a small proportion of land mangers reluctant to control, regardless of costs and benefits, could lead to the whole landscape being infested, even when local control stopped new infestations. Social pressure was important, but only if it was independent of weed prevalence, suggesting that early access to information, and incentives to act on that information, may be crucial in stopping a weed from infesting large areas. The response of our model to both

  5. An African grassland responds similarly to long-term fertilization to the Park Grass experiment.

    PubMed

    Ward, David; Kirkman, Kevin; Tsvuura, Zivanai

    2017-01-01

    We compared the results of a long-term (65 years) experiment in a South African grassland with the world's longest-running ecological experiment, the Park Grass study at Rothamsted, U.K. The climate is warm and humid in South Africa and cool and temperate in England. The African grassland has been fertilized with two forms of nitrogen applied at four levels, phosphorus and lime in a crossed design in 96 plots. In 1951, about 84% of plant cover consisted of Themeda triandra, Tristachya leucothrix and Setaria nigrirostris. Currently, the dominant species are Panicum maximum, Setaria sphacelata and Eragrostis curvula, making up 71% of total biomass. As in the Park Grass experiment, we found a significant (additive) interaction effect on ANPP of nitrogen and phosphorus, and a (marginally significant) negative correlation between ANPP and species richness. Unlike the Park Grass experiment, there was no correlation between ANPP and species richness when pH was included as a covariate. There was also a significant negative effect of nitrogen amount and nitrogen form and a positive effect of lime on species richness and species diversity. Soil pH had an important effect on species richness. Liming was insufficient to balance the negative effects on species richness of nitrogen fertilization. There was a significant effect of pH on biomass of three abundant species. There were also significant effects of light on the biomass of four species, with only Panicum maximum having a negative response to light. In all of the abundant species, adding total species richness and ANPP to the model increased the amount of variance explained. The biomass of Eragrostis curvula and P. maximum were negatively correlated with species richness while three other abundant species increased with species richness, suggesting that competition and facilitation were active. Consistent with the results from the Park Grass and other long-term fertilization experiments of grasslands, we found a

  6. An African grassland responds similarly to long-term fertilization to the Park Grass experiment

    PubMed Central

    Kirkman, Kevin; Tsvuura, Zivanai

    2017-01-01

    We compared the results of a long-term (65 years) experiment in a South African grassland with the world’s longest-running ecological experiment, the Park Grass study at Rothamsted, U.K. The climate is warm and humid in South Africa and cool and temperate in England. The African grassland has been fertilized with two forms of nitrogen applied at four levels, phosphorus and lime in a crossed design in 96 plots. In 1951, about 84% of plant cover consisted of Themeda triandra, Tristachya leucothrix and Setaria nigrirostris. Currently, the dominant species are Panicum maximum, Setaria sphacelata and Eragrostis curvula, making up 71% of total biomass. As in the Park Grass experiment, we found a significant (additive) interaction effect on ANPP of nitrogen and phosphorus, and a (marginally significant) negative correlation between ANPP and species richness. Unlike the Park Grass experiment, there was no correlation between ANPP and species richness when pH was included as a covariate. There was also a significant negative effect of nitrogen amount and nitrogen form and a positive effect of lime on species richness and species diversity. Soil pH had an important effect on species richness. Liming was insufficient to balance the negative effects on species richness of nitrogen fertilization. There was a significant effect of pH on biomass of three abundant species. There were also significant effects of light on the biomass of four species, with only Panicum maximum having a negative response to light. In all of the abundant species, adding total species richness and ANPP to the model increased the amount of variance explained. The biomass of Eragrostis curvula and P. maximum were negatively correlated with species richness while three other abundant species increased with species richness, suggesting that competition and facilitation were active. Consistent with the results from the Park Grass and other long-term fertilization experiments of grasslands, we found a

  7. Variability of annual CO2 exchange from Dutch grasslands

    NASA Astrophysics Data System (ADS)

    Jacobs, C. M. J.; Jacobs, A. F. G.; Bosveld, F. C.; Hendriks, D. M. D.; Hensen, A.; Kroon, P. S.; Moors, E. J.; Nol, L.; Schrier-Uijl, A.; Veenendaal, E. M.

    2007-10-01

    An intercomparison is made of the Net Ecosystem Exchange of CO2, NEE, for eight Dutch grassland sites: four natural grasslands, two production grasslands and two meteorological stations within a rotational grassland region. At all sites the NEE was determined during at least 10 months per site, using the eddy-covariance (EC) technique, but in different years. The NEE does not include any import or export other than CO2. The photosynthesis-light response analysis technique is used along with the respiration-temperature response technique to partition NEE into Gross Primary Production (GPP) and Ecosystem Respiration (Re) and to obtain the eco-physiological characteristics of the sites at the field scale. Annual sums of NEE, GPP and Re are then estimated using the fitted response curves with observed radiation and air temperature from a meteorological site in the centre of The Netherlands as drivers. These calculations are carried out for four years (2002-2005). Land use and management histories are not considered. The estimated annual Re for all individual sites is more or less constant per site and the average for all sites amounts to 1390±30 gC m-2 a-1. The narrow uncertainty band (±2%) reflects the small differences in the mean annual air temperature. The mean annual GPP was estimated to be 1325 g C m-2 a-1, and displays a much higher standard deviation, of ±110 gC m-2 a-1 (8%), which reflects the relatively large variation in annual solar radiation. The mean annual NEE amounts to -65±85 gC m-2 a-1. From two sites, four-year records of CO2 flux were available and analyzed (2002-2005). Using the weather record of 2005 with optimizations from the other years, the standard deviation of annual GPP was estimated to be 171-206 gC m-2 a-1 (8-14%), of annual Re 227-247 gC m-2 a-1 (14-16%) and of annual NEE 176-276 gC m-2 a-1. The inter-site standard deviation was higher for GPP and Re, 534 gC m-2 a-1 (37.3%) and 486 gC m-2 a-1 (34.8%), respectively. However, the inter

  8. Analysis of the influence of climatic and physiological parameters on the net ecosystem carbon exchange of an apple orchard

    NASA Astrophysics Data System (ADS)

    Zanotelli, Damiano; Montagnani, Leonardo; Scandellari, Francesca; Tagliavini, Massimo

    2013-04-01

    Net ecosystem carbon exchange (NEE) of an apple orchard located in South Tyrol (Caldaro, Bolzano, Italy) was monitored continuously since March 2009 via eddy covariance technique. Contemporary measurements of the main environmental parameters (temperature, photosynthetic active photon flux density, soil water content, vapor pressure deficit) were taken at the same field site. Leaf Area Index was also determined biometrically starting from spring 2010. Objectives of this work were (i) to assess the influence of these environmental and physiological parameters on NEE, (ii) to set up a model capable to fill large gap occurring in the dataset and (iii) predict inter-annual variability of fluxes based on the measurements of the selected explanatory variables. Daily cumulated values of the response variable (NEE, g C d-1) and mean daily value of the five explanatory variables considered (air T, ° C; SWC, m3m-3; PPFD, μmol m-2s-1; VPD, hPa, LAI m2m-2) were used in this analysis. The complex interactions between the explanatory variables and NEE were analyzed with the tree model approach which draws a picture of the complexity of data structure and highlights the explanatory variable that explain the greater amount of deviance of the response variable. NEE variability was mostly explained by LAI and PPFD. The most positive values of NEE occurred below the LAI threshold of 1.16 m2m-2 while above that LAI threshold and with an average daily PPFD above 13.2 μmol m-2s-1, the orchard resulted always a sink of carbon (negative daily NEE). On half of the available data (only alternate months of the considered period were considered), a stepwise multiple regression approach was used to model NEE using the variables indicated above. Simplification by deletion of the non-significant terms was carried out until all parameters where highly significant (p < 0.05) and a significant increase in deviance was observed when deleting further variables. Since heteroscedasticity and non

  9. Combining tower mixing ratio and community model data to estimate regional-scale net ecosystem carbon exchange by boundary layer inversion over four flux towers in the United States

    NASA Astrophysics Data System (ADS)

    Dang, Xuerui; Lai, Chun-Ta; Hollinger, David Y.; Schauer, Andrew J.; Xiao, Jingfeng; Munger, J. William; Owensby, Clenton; Ehleringer, James R.

    2011-09-01

    We evaluated an idealized boundary layer (BL) model with simple parameterizations using vertical transport information from community model outputs (NCAR/NCEP Reanalysis and ECMWF Interim Analysis) to estimate regional-scale net CO2 fluxes from 2002 to 2007 at three forest and one grassland flux sites in the United States. The BL modeling approach builds on a mixed-layer model to infer monthly average net CO2 fluxes using high-precision mixing ratio measurements taken on flux towers. We compared BL model net ecosystem exchange (NEE) with estimates from two independent approaches. First, we compared modeled NEE with tower eddy covariance measurements. The second approach (EC-MOD) was a data-driven method that upscaled EC fluxes from towers to regions using MODIS data streams. Comparisons between modeled CO2 and tower NEE fluxes showed that modeled regional CO2 fluxes displayed interannual and intra-annual variations similar to the tower NEE fluxes at the Rannells Prairie and Wind River Forest sites, but model predictions were frequently different from NEE observations at the Harvard Forest and Howland Forest sites. At the Howland Forest site, modeled CO2 fluxes showed a lag in the onset of growing season uptake by 2 months behind that of tower measurements. At the Harvard Forest site, modeled CO2 fluxes agreed with the timing of growing season uptake but underestimated the magnitude of observed NEE seasonal fluctuation. This modeling inconsistency among sites can be partially attributed to the likely misrepresentation of atmospheric transport and/or CO2 gradients between ABL and the free troposphere in the idealized BL model. EC-MOD fluxes showed that spatial heterogeneity in land use and cover very likely explained the majority of the data-model inconsistency. We show a site-dependent atmospheric rectifier effect that appears to have had the largest impact on ABL CO2 inversion in the North American Great Plains. We conclude that a systematic BL modeling approach

  10. Phenological control over ecosystem-atmosphere carbon exchange (Invited)

    NASA Astrophysics Data System (ADS)

    Monson, R. K.; Moore, D. J.; Scott-Denton, L.; Burns, S. P.

    2010-12-01

    Our understanding of ecosystem-atmosphere carbon fluxes has been improved over the past decade in large part due to the maturation of observational records from networks of flux towers and the development of model-data assimilation techniques from which insight into carbon cycle processes can be extracted. Some of the earliest analyses of the observation record revealed that interannual phenological variation in forest ecosystems has a significant influence on the annual cumulative net rate of CO2 uptake from the atmosphere. In winter-deciduous forest ecosystems, phenological variability in the timing of bud break in the spring, and the early-season rate at which the forest reaches its seasonal maximum leaf area index, have large effects on the ultimate annual sum for net ecosystem CO2 exchange (NEE). In snow-controlled evergreen forests, the timing at which snow melt or soil thaw occurs, and liquid water becomes available to drive diurnal increases in stomatal conductance, the spring 'phenological switch-on' can be abrupt and the capacity for the forest to reach its seasonal maximum NEE can occur within a few days. The relatively high sensitivity of ecosystem carbon budgets to variability in phenology renders it difficult to accurately model system dynamics, especially for evergreen forests. Recent model-data assimilation studies have found large errors in the ability of the models to replicate observations of NEE at the seasonal-to-annual time scales, in large part due to inadequacies in how they capture spring and fall phenology thresholds and early- and late-season dynamics in the state of the photosynthetic apparatus. In our own studies of interannual variation in NEE in the evergreen subalpine forest at Niwot Ridge, Colorado, we have not been able to accurately represent spring phenology dynamics and their influence on annual NEE using the Simple Evapotranspiration and Net Photosynthesis (SIPNET) model without explicit consideration of snowmelt dynamics. In

  11. Individual rain events decrease long-term boreal peatland net CO2 uptake through reduced light availability

    NASA Astrophysics Data System (ADS)

    Nijp, Jelmer; Limpens, Juul; Metselaar, Klaas; Peichl, Matthias; Nilsson, Mats B.; van der Zee, Sjoerd; Berendse, Frank

    2016-04-01

    Northern peatlands sequester enormous quantities of carbon, suggesting these wetland ecosystems are of fundamental importance for the global carbon cycle. The long-term carbon storage of these wetland ecosystems depends on wet surface conditions, and is prone to drought. Future climate predictions indicate that most of the northern hemisphere is projected to become wetter, but that precipitation will fall in less frequent but more intense events. How such fine-scale climatic changes will affect long-term future net ecosystem exchange (NEE) of northern peatlands remains unknown. In this study we explored the short-term peatland NEE response to day time rain events during the growing season, how timing and characteristics of individual events and environmental conditions modify this response, and the impact of NEE responses to individual rain events for the longer-term (annual) carbon uptake. We used an 11-year time series of half-hourly eddy covariance and meteorological measurements from Degerö Stormyr, a peatland in northern Sweden. Our study shows daytime precipitation events systematically decreased the sink strength for atmospheric CO2. An individual daytime precipitation event reduced net ecosystem CO2 uptake by 0.23-0.54 gC m-2 on average. This reduction was best explained by the reduction in light associated with precipitation events, rather than by precipitation characteristics, timing of events, or drought length. On an annual basis, this reduction of net CO2 uptake corresponds to 24% of the annual net CO2 uptake (NEE) of the study site, equivalent to a 4.4% reduction of gross primary production (GPP) during the growing season. We conclude that accounting for the short-term response of NEE to individual rain events is crucial in determining climate change impacts on long-term sink strength of peatlands to atmospheric CO2. Moreover, reduced light availability associated with rain events is more important in explaining the NEE response to rain events than

  12. Arctic ecosystem responses to changes in water table and surface warming

    NASA Astrophysics Data System (ADS)

    Olivas, P. C.; Oberbauer, S. F.; Tweedie, C. E.; Oechel, W. C.

    2009-12-01

    Although low in productivity, arctic ecosystems store close to 20% of the global soil carbon as a result of low decomposition rates enhanced by high soil moisture availability and low temperatures. Expected global climatic changes are likely to significantly increase the temperature in the Arctic, disturbing surface soil moisture patterns and potentially increasing turnover of soil organic matter, thus reversing the role of the Arctic as a carbon sink. Our goal was to determine the short-term ecosystem CO2 exchange response to drying, flooding, and warming, and understand the potential effects that climatic changes could have on the long-term carbon balance of the Arctic. We carried out this study during the growing seasons from 2006 to 2008 on the coastal plain near Barrow, Alaska. We used a 62 ha thawed lake, divided into three sections: drained, flooded and intermediate treatments. Temperature treated plots were replicated within each water treatment category using open top chambers. We assessed ecosystem responses to water and temperature treatments as: ecosystem respiration (ER), gross primary photosynthesis (GPP) and net ecosystem balance (NEE) using chamber-based measurements. We found a strong CO2 exchange response to changes in water table and surface temperature. However, the magnitude of the response differed among carbon flux components. Although flooding increased NEE, the increase was more a result of a decrease in ER rather than an increase in GPP. High water tables can also reduce GPP by submerging leaf area, especially that of mosses. Drying increased ER and GPP, however, species composition and microtopography position affected the magnitude of the changes ultimately affecting NEE. Areas dominated by mosses experienced a reduction of sink capacity, whereas areas dominated by vascular plants experienced an increase in NEE regardless of the drying of the moss layer. Warming affected all CO2 flux components. GPP increased in all treatments except in

  13. Invasive C4 Perennial Grass Alters Net Ecosystem Exchange in Mixed C3/C4 Savanna Grassland

    NASA Astrophysics Data System (ADS)

    Basham, T. S.; Litvak, M.

    2006-12-01

    The invasion of ecosystems by non-native plants that differ from native plants in physiological characteristics and phenology has the potential to alter ecosystem function. In Texas and other regions of the southern central plains of the United States, the introduced C4 perennial grass, Bothriochloa ischaemum, invades C3/C4 mixed grasslands and savannas, resulting in decreased plant community diversity (Gabbard 2003; Harmoney et al 2004). The objective of this study was to quantify how the conversion of these mixed grass communities to C4 dominated, B. ischaemum monocultures impacts carbon cycling and sequestration. Seasonal measurements of Net Ecosystem Exchange (NEE) of CO2, leaf level gas exchange and soil respiration were compared between savanna grassland plots composed of either naturally occurring B. ischaemum monocultures or native mixed grasses (n=16). NEE was measured using a closed system chamber that attached to permanently installed stainless steel bases. Temperature, soil moisture, aerial percent species cover and leaf area index were also monitored in plots to explain variability in measured responses. Results showed that NEE differed seasonally between invaded and native plots due to 1) greater leaf surface area per unit ground area in invaded plots, 2) differences in phenological patterns of plant activity and 3) differences in responses to water limitation between invaded and native plots. Cold season and summer drought NEE were driven primarily by belowground respiration in both plot types, however spring uptake activity commenced two months later in invaded plots. This later start in invaded plots was compensated for by greater uptake throughout the growing season and in particular during the drier summer months. Differences in NEE between plot types were not due to differences in soil respiration nor were they due to greater leaf level photosynthetic capabilities of B. ischaemum relative to the dominant native grasses. NEE, soil respiration and

  14. Environmental Control of Net Ecosystem Carbon Dioxide Exchange in Contrasting Peatlands in northern Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Syed, K. H.; Carlson, P. J.; Glenn, A. J.; Flanagan, L. B.

    2004-12-01

    Peatlands cover about 21 per cent of the landscape and contain about 80 per cent of the soil carbon stock in western Canada. However, the current rates of carbon accumulation and the environmental controls on ecosystem photosynthesis and respiration in peatland ecosystems is poorly understood. As part of Fluxnet-Canada, we continuously measured net ecosystem carbon dioxide exchange (NEE) using the eddy covariance technique in a treed fen (main site) dominated by stunted black spruce and larch trees during August 2003 through July 2004. Additional NEE measurements were made at two auxiliary sites during intervals in the active growing season (May through September 2004). One auxiliary site was dominated by Sphagnum moss, while the dominant species at other site were Carex and brown mosses. The NEE measurements were used to develop statistical models to assess temporal variation in physiological parameters for ecosystem photosynthesis and respiration. Large seasonal changes occurred in maximum photosynthetic capacity and standardized ecosystem respiration rate at 10 degrees C (R10). The mid-day NEE uptake rate during July averaged 10 μ mol m-2 s-1 at the main site, while lower values of approximately 6 μ mol m-2 s-1 were observed at the two auxiliary sites. No photosynthetic activity was observed during mid-November through mid-March. On an annual basis R10 varied from less than 0.5 μ mol m-2 s-1 in the winter to approximately 3 μ mol m-2 s-1 during August at the main site. During much of the growing season, a distinct hysteresis was observed in the light (photon flux density, PFD) response curves for NEE between morning and afternoon periods. This was caused by large diurnal changes in temperature, which at times resulted in the light compensation point for NEE shifting from a PFD of 100 μ mol m-2 s-1 in the morning to 350 μ mol m-2 s-1 in the afternoon. The main site recorded a net annual gain of 160 g C m-2 yr-1, the result of a difference between gross

  15. Early Season Goose Grazing Has a Greater Effect Than Advancement of the Growing Season on Net Ecosystem Exchange in a Sub-Arctic Coastal Wetland of Western Alaska

    NASA Astrophysics Data System (ADS)

    Leffler, A. J.; Choi, R. T.; Beard, K. H.; Schmutz, J. A.; Welker, J. M.

    2014-12-01

    The wetlands of the Yukon-Kuskokwim Delta in western Alaska are important breeding areas for geese and are experiencing rapid climate change. Growing seasons now begin earlier but geese have not advanced their breeding enough to match the advancement of spring. Consequently, geese enter a greener system that may be less nutritious than in the past because grasses and sedges have highest nutrient density shortly following emergence. One consequence of this changing phenology is that vegetation consumed by geese and returned as feces may have a different carbon to nitrogen ratio than in the past, which may influence net ecosystem exchange (NEE). We examine the effect of the advancement of the growing season and different arrival times by Brant Geese on NEE. Our study consists of six experimental blocks, each with nine plots. Half of the plots are warmed to advance the growing season. Two plots each receive early, mid, and late season grazing; the remaining two plots are not grazed and there is one control plot. In one block, we monitor NEE hourly with an automatic gas exchange system. In the other blocks, survey measurements of NEE and ecosystem respiration (ER) are made periodically with a portable system. Geese remove considerable vegetation from the system and maintain "grazing lawns" <1 cm tall of high quality forage. Plots grazed in the early summer were net sources of C to the atmosphere, releasing ca. 2-4 g m-2 d-1. Non-grazed plots were C sinks of similar magnitude. Grazing had little effect on ER but an advanced growing season enhanced ER in the plots by ca. 0.5 μmol m-2 s-1. We observed a similar advanced growing season effect on NEE that we attribute to enhanced ER. Consequently, the larger influence on NEE in the system is grazing and this influence is through removal of photosynthetic tissue. Grazing by Brant Geese shifts large areas of this coastal wetland to a C source while advanced growing season only reduces the strength of the C sink.

  16. Ecohydrological and Biophysical Controls on Carbon Cycling in Two Seasonally Snow-covered Forests

    NASA Astrophysics Data System (ADS)

    Chan, A. M.; Brooks, P. D.; Burns, S. P.; Litvak, M. E.; Blanken, P.; Bowling, D. R.

    2014-12-01

    In many seasonally snow-covered forests, the snowpack is the primary water resource. The snowpack also serves as an insulating layer over the soil, warming soil throughout the winter and preserving moisture conditions from the preceding fall. Therefore, the total amount of water in the snowpack as well as the timing and duration of the snow-covered season are likely to have a strong influence on forest productivity through the regulation of the biophysical environment. We investigated how interannual variation in the amount and timing of seasonal snow cover affect winter carbon efflux and growing season carbon uptake at the Niwot Ridge AmeriFlux site (NWT) in Colorado (3050m a.s.l.; 40˚N) and the Valles Caldera Mixed-Conifer AmeriFlux site (VC) in New Mexico (3003m a.s.l.; 36˚N). The tree species composition at NWT is dominated by Abies lasiocarpa, Picea engelmannii, and Pinus contorta. At VC, the dominant tree species are Pseudotsuga menziesii, Abies concolor, Picea pungens, Pinus strobiformis, Pinus flexilis, Pinus ponderosa, and Populus tremuloides. We used net ecosystem exchange (NEE) and climate data from 1999-2012 at NWT and 2007-2012 at VC to divide each year into the growing season, when NEE is negative, and the winter, when NEE is positive. Snow water equivalent (SWE), precipitation, and duration of snow cover data were obtained from USDA/NRCS SNOTEL sites near each forest. At both sites, the start of the growing season was strongly controlled by air temperature, but growing season NEE was not dependent on the length of the growing season. At NWT, total winter carbon efflux was strongly influenced by both the amount and duration of the snowpack, measured as SWE integrated over time. Years with higher integrated SWE had higher winter carbon efflux and also had warmer soil under the snowpack. These patterns were not seen at VC. However, peak SWE amount was positively correlated with growing season NEE at VC, but not at NWT. These results suggest that

  17. Weed-cover versus weed-removal management in olive orchards: influence on the carbon balance at the ecosystem scale

    NASA Astrophysics Data System (ADS)

    Chamizo, Sonia; Serrano-Ortiz, Penélope; Vicente-Vicente, José Luis; Sánchez-Cañete, Enrique P.; López-Ballesteros, Ana; Kowalski, Andrew S.

    2016-04-01

    Agriculture plays an important role in the C budget at the global scale. Traditional practices based on soil tillage and applying herbicides to remove weeds have caused damage to soils and led to important losses of soil organic C and increased CO2 emissions to the atmosphere. Changing trends from traditional agriculture to conservation agriculture practices may have an important role in both C and water budgets and the transformation of agriculture from C source to C sink. The objective of this study was to analyse the effect of two treatments, weed removal by herbicides versus weed cover conservation, on the C balance in an irrigated olive orchard in SE Spain. Measurements of CO2 exchange were made from October 2014 to September 2015 using two eddy covariance towers, one for each olive crop treatment. Results show that CO2 fluxes at the ecosystem scale were similar in the two treatments during initial conditions, prior to weed growth in the soils without herbicide application (October). During the first week, daily net ecosystem exchange (NEE) was close to zero in both treatments, with values ranging from 1.06 to -0.41 g C m-2 in the weed cover treatment, and from 0.76 to -0.69 g C m-2 in the weed removal treatment. As weed growth increased, higher net CO2 assimilation was found in the treatment with weed cover. In both treatments, maximum net CO2 assimilation was found in March, with a monthly NEE of -72 and -28 g C m-2 in the treatment with and without weed cover, respectively. In May, after the weeds were cut and left on the soil, a strong increase was observed in NEE in the treatment with weed cover due to decreased CO2 assimilation and increased respiration compared to the treatment without weed cover. Therefore, soil chamber measurements showed average respiration rates of 2.57 and 1.57 μmol m-2 s-2 in the weed cover and weed removal treatment, respectively. Finally, the highest monthly NEE was registered during July, with both treatments showing a similar

  18. Temporal patterns of net CO2 exchange for a tropical semideciduous forest of the southern Amazon Basin

    NASA Astrophysics Data System (ADS)

    Vourlitis, George L.; de Almeida Lobo, Francisco; Zeilhofer, Peter; de Souza Nogueira, José

    2011-09-01

    The carbon cycling of tropical ecosystems has received considerable attention over the last 1-2 decades; however, interactions between climate variation and tropical forest net ecosystem CO2 exchange (NEE) are still uncertain. To reduce this uncertainty, and assess the biophysical controls on NEE, we used the eddy covariance method over a 3 year period (2005-2008) to measure the CO2 flux and energy balance for a 25-28 m tall, mature tropical semideciduous forest located near Sinop Mato Grosso, Brazil. The study period encompassed warm-dry, cool-wet, and cool-dry climate conditions, and based on previous research, we hypothesized that the net CO2 accumulation of the semideciduous forest would be lower during periods of drought. Using time series of the enhanced vegetation index (EVI), a NEE-light-use model, and path analysis, we found that the estimated quantum yield (a', μmol CO2μmol photons-1) was directly affected by temporal variations in the EVI, precipitation, and photosynthetically active radiation (PAR), while the optimal rate of gross primary production (FGPP,opt, μmol m-2 s-1) was directly affected by the EVI and PAR. However, indirect effects of precipitation on the a' and FGPP,opt were stronger than direct effects because variations in precipitation also lead to variations in the EVI and the atmospheric vapor pressure deficit (VPD). Daytime ecosystem respiration (FRE,day, μmol m-2 s-1) was directly affected by temporal variations in temperature and VPD and indirect effects of other variables were of lesser importance. Net ecosystem CO2 uptake was often higher in the dry season than the wet season, not because of a dry season "green-up" but because rates of ecosystem respiration declined relatively more than rates of canopy photosynthesis. Over interannual timescales, average daily NEE increased over the 3 year study period and was highest in 2007-2008, which was also the driest year in terms of rainfall. However, 2007-2008 was also the coolest year

  19. Measurement-based upscaling of Pan Arctic Net Ecosystem Exchange: the PANEEx project

    NASA Astrophysics Data System (ADS)

    Njuabe Mbufong, Herbert; Kusbach, Antonin; Lund, Magnus; Persson, Andreas; Christensen, Torben R.; Tamstorf, Mikkel P.; Connolly, John

    2016-04-01

    The high variability in Arctic tundra net ecosystem exchange (NEE) of carbon (C) can be attributed to the high spatial heterogeneity of Arctic tundra due to the complex topography. Current models of C exchange handle the Arctic as either a single or few ecosystems, responding to environmental change in the same manner. In this study, we developed and tested a simple pan Arctic NEE (PANEEx) model using the Misterlich light response curve (LRC) function with photosynthetic photon flux density (PPFD) as the main driving variable. Model calibration was carried out with eddy covariance carbon dioxide (CO2) data from 12 Arctic tundra sites. The model input parameters (Fcsat, Rd and α) were estimated as a function of air temperature (AirT) and leaf area index (LAI) and represent specific characteristics of the NEE-PPFD relationship, including the saturation flux, dark respiration and initial light use efficiency, respectively. LAI and air temperature were respectively estimated from empirical relationships with remotely sensed normalized difference vegetation index (NDVI) and land surface temperature (LST). These are available as MODIS Terra product MOD13Q1 and MOD11A1 respectively. Therefore, no specific knowledge of the vegetation type is required. The PANEEx model captures the spatial heterogeneity of the Arctic tundra and was effective in simulating 77% of the measured fluxes (r2 = 0.72, p < 0.001) at the 12 sites used in the calibration of the model. Further, the model effectively estimates NEE in three disparate Alaskan ecosystems (heath, tussock and fen) with an estimation ranging between 10 - 36% of the measured fluxes. We suggest that the poor agreement between the measured and modeled NEE may result from the disparity between ground-based measured LAI (used in model calibration) and remotely sensed LAI (estimated from NDVI and used in NEE estimation). Moreover, our results suggests that using simple linear regressions may be inadequate as parameters estimated

  20. Unmasking the effect of a precipitation pulse on the biological processes composing Net Ecosystem Carbon Exchange

    NASA Astrophysics Data System (ADS)

    Lopez-Ballesteros, Ana; Sanchez-Cañete, Enrique P.; Serrano-Ortiz, Penelope; Oyonarte, Cecilio; Kowalski, Andrew S.; Perez-Priego, Oscar; Domingo, Francisco

    2015-04-01

    Drylands occupy 47.2% of the global terrestrial area and are key ecosystems that significantly determine the inter-annual variability of the global carbon balance. However, it is still necessary to delve into the functional behavior of arid and semiarid ecosystems due to the complexity of drivers and interactions between underpinning processes (whether biological or abiotic) that modulate net ecosystem CO2 exchange (NEE). In this context, water inputs are crucial to biological organisms survival in arid ecosystems and frequently arrive via rain events that are commonly stochastic and unpredictable (i.e. precipitation pulses) and strongly control arid land ecosystem structure and function. The eddy covariance technique can be used to investigate the effect of precipitation pulses on NEE, but provide limited understanding of what exactly happens after a rain event. The chief reasons are that, firstly, we cannot measure separately autotrophic and heterotrophic components, and secondly, the partitioning techniques widely utilized to separate Gross Primary Production and Total Ecosystem Respiration, do not work properly in these water-limited ecosystems, resulting in biased estimations of plant and soil processes. Consequently, it is essential to combine eddy covariance measurements with other techniques to disentangle the different biological processes composing NEE that are activated by a precipitation pulse. Accordingly, the main objectives of this work were: (i) to quantify the contribution of precipitation pulse events to annual NEE using the eddy covariance technique in a semiarid steppe located in Almería (Spain), and (ii) to simulate a realistic precipitation pulse in order to understand its effect on the ecosystem, soil and plant CO2 exchanges by using a transitory-state closed canopy chamber, soil respiration chambers and continuous monitoring CO2 sensors inserted in the subsoil. Preliminary results showed, as expected, a delay between soil and plant

  1. Growing season variability in carbon dioxide exchange of irrigated and rainfed soybean in the southern United States.

    PubMed

    Wagle, Pradeep; Gowda, Prasanna H; Anapalli, Saseendran S; Reddy, Krishna N; Northup, Brian K

    2017-09-01

    Measurement of carbon dynamics of soybean (Glycine max L.) ecosystems outside Corn Belt of the United States (U.S.) is lacking. This study examines the seasonal variability of net ecosystem CO2 exchange (NEE) and its components (gross primary production, GPP and ecosystem respiration, ER), and relevant controlling environmental factors between rainfed (El Reno, Oklahoma) and irrigated (Stoneville, Mississippi) soybean fields in the southern U.S. during the 2016 growing season. Grain yield was about 1.6tha(-1) for rainfed soybean and 4.9tha(-1) for irrigated soybean. The magnitudes of diurnal NEE (~2-weeks average) reached seasonal peak values of -23.18 and -34.78μmolm(-2)s(-1) in rainfed and irrigated soybean, respectively, approximately two months after planting (i.e., during peak growth). Similar thresholds of air temperature (Ta, slightly over 30°C) and vapor pressure deficit (VPD, ~2.5kPa) for NEE were observed at both sites. Daily (7-day average) NEE, GPP, and ER reached seasonal peak values of -4.55, 13.54, and 9.95gCm(-2)d(-1) in rainfed soybean and -7.48, 18.13, and 14.93gCm(-2)d(-1) in irrigated soybean, respectively. The growing season (DOY 132-243) NEE, GPP, and ER totals were -54, 783, and 729gCm(-2), respectively, in rainfed soybean. Similarly, cumulative NEE, GPP, and ER totals for DOY 163-256 (flux measurement was initiated on DOY 163, missing first 45days after planting) were -291, 1239, and 948gCm(-2), respectively, in irrigated soybean. Rainfed soybean was a net carbon sink for only two months, while irrigated soybean appeared to be a net carbon sink for about three months. However, grain yield and the magnitudes and seasonal sums of CO2 fluxes for irrigated soybean in this study were comparable to those for soybean in the U.S. Corn Belt, but they were lower for rainfed soybean. Published by Elsevier B.V.

  2. Identifying Signatures of Climatic Influence on Forest Net Carbon Exchange From 20 years of Observations at Harvard Forest

    NASA Astrophysics Data System (ADS)

    Munger, J. W.; Wofsy, S. C.; Lindaas, J.; Keenan, T. F.

    2012-12-01

    A major goal of carbon cycle science has been to understand the influence of climate on the carbon budgets of important ecosystems. Climate will influence ecosystems both through shifts in the mean state and changes in frequency and intensity of extreme events. The components of net ecosystem carbon exchange (NEE), photosynthesis and respiration, may respond independently and separately to climatic controls. This complicates attribution of NEE variations directly to climatic control.. The 20 year carbon flux record at Harvard Forest is an ideal data set to examine the climatic influence on NEE because it is long enough that changes in mean climate are detectable, and it includes multiple incidents of different extreme events. Our approach determines a mean functional response to environmental variables and uses this response to generate a predicted response to direct climate forcing. The difference between observations and this prediction (Figure 1) can be examined to identify changes in ecosystem function associated with climate anomalies and extreme events. An important observation from this analysis is that direct climate forcing by temperature and light does not account for interannual variability and long-term trends in NEE. Whether the mean response is defined by statistical fitting, or a process-based ecosystem model the predictions capture hourly variations driven by diel cycles, and annual seasonality, but do not reproduce the patterns observed at longer time scales. Warmer mean temperatures have extended the frost-free season and we observe earlier onset of net carbon uptake in the spring and continuation of net carbon uptake later into the fall. Extreme events, which have left detectable evidence of change in ecosystem structure, include severe ice storms, tropical storms, short-term droughts, and a wide variation in winter temperatures and depth of snow. Weather anomalies, however, tend to be short and influence particular seasons rather than affecting

  3. Sensitivity of the boreal forest-mire ecotone CO2, CH4, and N2O global warming potential to rainy and dry weather

    NASA Astrophysics Data System (ADS)

    Ťupek, Boris; Minkkinen, Kari; Vesala, Timo; Nikinmaa, Eero

    2015-04-01

    In a mosaic of well drained forests and poorly drained mires of boreal landscape the weather events such as drought and rainy control greenhouse gas dynamics and ecosystem global warming potential (GWP). In forest-mire ecotone especially in ecosystems where CO2 sink is nearly balanced with CO2 source, it's fairly unknown whether the net warming effect of emissions of gases with strong radiative forcing (CH4 and N2O) could offset the net cooling effect of CO2 sequestration. We compared the net ecosystem CO2 exchange (NEE) estimated from the carbon sequestrations of forest stands and forest floor CO2 fluxes against CH4 and N2O fluxes of nine forest/mire site types along the soil moisture gradient in Finland. The ground water of nine sites changed between 10 m in upland forests and 0.1 m in mires, and weather during three years ranged between exceptionally wet and dry for the local climate. The NEE of upland forests was typically a sink of CO2, regardless the weather. Though, xeric pine forest was estimated to be a source of CO2 during wet and intermediate year and became a weak sink only in dry year. The NEE of forest-mire transitions ranged between a sink in dry year, while increased stand carbon sequestration could offset the reduced forest floor CO2 emission, and a source in wet year. The NEE of two sparsely forested mires strongly differed. The lawn type mire was balanced around zero and the hummock type mire was relatively strong NEE sink, regardless the weather. Generally, nearly zero N2O emission could not offset the cooling effect of net CH4 sink and net CO2 sink of upland forest and forest-mire transitions. However in sparsely forested mires, with N2O emission also nearly zero, the CH4 emission during wet and intermediate year played important role in turning the net cooling effect of NEE into a net warming. When evaluating GWP of boreal landscapes, undisturbed forest-mire transitions should be regarded as net cooling ecosystems instead of hotspots of net

  4. Establishment of three new genera in the family Geminiviridae: Becurtovirus, Eragrovirus and Turncurtovirus.

    PubMed

    Varsani, Arvind; Navas-Castillo, Jesús; Moriones, Enrique; Hernández-Zepeda, Cecilia; Idris, Ali; Brown, Judith K; Murilo Zerbini, F; Martin, Darren P

    2014-08-01

    The family Geminiviridae includes plant-infecting circular single-stranded DNA viruses that have geminate particle morphology. Members of this family infect both monocotyledonous and dicotyledonous plants and have a nearly global distribution. With the advent of new molecular tools and low-cost sequencing, there has been a significant increase in the discovery of new geminiviruses in various cultivated and non-cultivated plants. In this communication, we highlight the establishment of three new genera (Becurtovirus, Eragrovirus and Turncurtovirus) to accommodate various recently discovered geminiviruses that are highly divergent and, in some cases, have unique genome architectures. The genus Becurtovirus has two viral species, Beet curly top Iran virus (28 isolates; leafhopper vector Circulifer haematoceps) and Spinach curly top Arizona virus (1 isolate; unknown vector), whereas the genera Eragrovirus and Turncurtovirus each have a single assigned species: Eragrostis curvula streak virus (6 isolates; unknown vector) and Turnip curly top virus (20 isolates; leafhopper vector Circulifer haematoceps), respectively. Based on analysis of all of the genome sequences available in public databases for each of the three new genera, we provide guidelines and protocols for species and strain classification within these three new genera.

  5. Germination characteristics of Andropogon virginicus L

    SciTech Connect

    Farmer, R.E. Jr.; Cunningham, M.; Brown, J.E.

    1980-12-01

    The natural occurrence of broomsedge (Andropogon virginicus L.) as a pioneer species on orphan strip mines with acid soils (pH 3.0-4.0) and other areas of low fertility suggests that it may have value in revegetation systems for disturbed sites. This study was conducted to delineate seed dormancy and germination characteristics important to developing seeding procedures. Freshly collected seed from east Tennessee germinated to about 50 percent under light at 20-30/sup 0/C, but did not germinate at lower temperatures. If stored in a low-humidity, low-temperature environment, seed developed a deeper dormancy, which was broken by moist chilling. This chilling first enabled germination at high temperatures and in light; as chilling time increased, seed developed a capability for germination in the dark and at low temperatures. In a preliminary seeding trial on an acid (pH 4.0) minesoil, broomsedge survived and grew better than commonly used species such as Festuca arundinacea and Eragrostis curvula.

  6. A highly divergent South African geminivirus species illuminates the ancient evolutionary history of this family

    PubMed Central

    Varsani, Arvind; Shepherd, Dionne N; Dent, Kyle; Monjane, Aderito L; Rybicki, Edward P; Martin, Darren P

    2009-01-01

    Background We have characterised a new highly divergent geminivirus species, Eragrostis curvula streak virus (ECSV), found infecting a hardy perennial South African wild grass. ECSV represents a new genus-level geminivirus lineage, and has a mixture of features normally associated with other specific geminivirus genera. Results Whereas the ECSV genome is predicted to express a replication associated protein (Rep) from an unspliced complementary strand transcript that is most similar to those of begomoviruses, curtoviruses and topocuviruses, its Rep also contains what is apparently a canonical retinoblastoma related protein interaction motif such as that found in mastreviruses. Similarly, while ECSV has the same unusual TAAGATTCC virion strand replication origin nonanucleotide found in another recently described divergent geminivirus, Beet curly top Iran virus (BCTIV), the rest of the transcription and replication origin is structurally more similar to those found in begomoviruses and curtoviruses than it is to those found in BCTIV and mastreviruses. ECSV also has what might be a homologue of the begomovirus transcription activator protein gene found in begomoviruses, a mastrevirus-like coat protein gene and two intergenic regions. Conclusion Although it superficially resembles a chimaera of geminiviruses from different genera, the ECSV genome is not obviously recombinant, implying that the features it shares with other geminiviruses are those that were probably present within the last common ancestor of these viruses. In addition to inferring how the ancestral geminivirus genome may have looked, we use the discovery of ECSV to refine various hypotheses regarding the recombinant origins of the major geminivirus lineages. PMID:19321000

  7. Identification, cloning, and characterization of PWL2, a gene for host species specificity in the rice blast fungus.

    PubMed Central

    Sweigard, J A; Carroll, A M; Kang, S; Farrall, L; Chumley, F G; Valent, B

    1995-01-01

    Genetic analysis of host specificity in the rice blast fungus (Magnaporthe grisea) identified a single gene, PWL2 (for Pathogenicity toward Weeping Lovegrass), that exerts a major effect on the ability of this fungus to infect weeping lovegrass (Eragrostis curvula). The allele of the PWL2 gene conferring nonpathogenicity was genetically unstable, with the frequent appearance of spontaneous pathogenic mutants. PWL2 was cloned based on its map position. Large deletions detected in pathogenic mutants guided the gene cloning efforts. Transformants harboring the cloned PWL2 gene lost pathogenicity toward weeping lovegrass but remained fully pathogenic toward other host plants. Thus, the PWL2 host species specificity gene has properties analogous to classical avirulence genes, which function to prevent infection of certain cultivars of a particular host species. The PWL2 gene encodes a glycine-rich, hydrophilic protein (16 kD) with a putative secretion signal sequence. The pathogenic allele segregating in the mapping population, pwl2-2, differed from PWL2 by a single base pair substitution that resulted in a loss of function. The PWL2 locus is highly polymorphic among rice pathogens from diverse geographic locations. PMID:7549480

  8. High diversity of fungi may mitigate the impact of pollution on plant litter decomposition in streams.

    PubMed

    Duarte, Sofia; Pascoal, Cláudia; Cássio, Fernanda

    2008-11-01

    We investigated how a community of microbial decomposers adapted to a reference site responds to a sudden decrease in the water quality. For that, we assessed the activity and diversity of fungi and bacteria on decomposing leaves that were transplanted from a reference (E1) to a polluted site (E2), and results were compared to those from decomposing leaves either at E1 or E2. The two sites had contrasting concentrations of organic and inorganic nutrients and heavy metals in the stream water. At E2, leaf decomposition rates, fungal biomass, and sporulation were reduced, while bacterial biomass was stimulated. Fungal diversity was four times lower at the polluted site. The structure of fungal community on leaves decomposing at E2 significantly differed from that decomposing at E1, as indicated by the principal response curves analysis. Articulospora tetracladia, Anguillospora filiformis, and Lunulospora curvula were dominant species on leaves decomposing at E1 and were the most negatively affected by the transfer to the polluted site. The transfer of leaves colonized at the reference site to the polluted site reduced fungal diversity and sporulation but not fungal biomass and leaf decomposition. Overall, results suggest that the high diversity on leaves from the upstream site might have mitigated the impact of anthropogenic stress on microbial decomposition of leaves transplanted to the polluted site.

  9. Leaf Barriers to Fungal Colonization and Shredders (Tipula lateralis) Consumption of Decomposing Eucalyptus globulus.

    PubMed

    Canhoto; Graça

    1999-04-01

    > Abstract Herein we assess the importance of leaf cuticle, polyphenolic, and essential oils contents of Eucalyptus globulus leaves to hyphomycete colonization and shredder consumption. Optical and electron microscopy revealed that, at least during the first 5 weeks of conditioning, the cuticle remains virtually intact. Stomata provide the main access for hyphae to internal leaf tissues and, eventually, for spore release. We suggest that in E. globulus leaves, fungal decomposition progresses predominantly in and from the eucalyptus leaf mesophyll to the outside. Malt extract agar media supplemented with either eucalyptus essential oils or tannic acid completely inhibited (Articulospora tetracladia, Lemonniera aquatica, and Tricladium gracile) or depressed (Heliscus lugdunensis, Lunulospora curvula, and Tricladium angulatum) aquatic hyphomycetes growth. The transference of both secondary compounds to alder leaves induced similar and significant reduction in Tipula lateralis larval consumption. Results consistently indicate that eucalyptus oils are stronger deterrents than polyphenols. The waxy cuticle of E. globulus appears to be a key physical factor delaying fungal colonization during decomposition. We hypothesize that the relative influence of leaf phenols and essential oils to aquatic hyphomycetes and shredders may be related to three main factors: (a) initial distribution of such compounds in the leaves; (b) possibility of their decrease through decomposition; and (c) consumption strategies of detritivores.

  10. Aquatic hyphomycete communities as potential bioindicators for assessing anthropogenic stress.

    PubMed

    Solé, M; Fetzer, I; Wennrich, R; Sridhar, K R; Harms, H; Krauss, G

    2008-01-25

    With a profound knowledge of how physico-chemical parameters affect these communities, microbial communities could be used as indicators for environmental changes and for risk assessment studies. We studied aquatic hyphomycete communities in rivers and aquifers from sites shaped by intense mining activities (namely the "Mansfeld region") and chemical industry (cities of Halle and Bitterfeld) in Central Germany. Environmental stress factors such as high concentrations of heavy metals, sulphate, and nitrate as well as low concentrations of oxygen significantly reduced the diversity and biomass of hyphomycetes in the investigated samples. Redundancy analysis (RDA) indicates that variations in water chemistry cause a significant proportion of the change in fungal community structure (86.2%). Fungi were negatively correlated with high metal and nutrient concentrations. RDA also showed a strong influence of organic matter on individual species, with Anguillospora longissima (Sacc. et Syd.), Clavatospora longibrachiata (Ingold), Clavariopsis aquatica (De Wild), Flagellospora curvula (Ingold), Heliscus lugdunensis (Sacc. et Thérry), Tumularia aquatica (Ingold) and Lemonniera aquatica (De Wild) being most sensitive. We propose that aquatic hyphomycete communities can be used as sensitive and integrative indicators for freshwater quality.

  11. Classifying increaser species as an indicator of different levels of rangeland degradation using WorldView-2 imagery

    NASA Astrophysics Data System (ADS)

    Mansour, Khalid; Mutanga, Onisimo

    2012-01-01

    The development of new multispectral sensors with unique band settings is critical for mapping the spatial distribution of increaser vegetation species in disturbed rangelands. The objective of this study was to evaluate the potential of WorldView-2 imagery for spectral classification of four increaser species, namely Hyparrhenia hirta, Eragrostis curvula, Sporobolus africanus, and Aristida diffusa, in the Okhombe communal rangelands of South Africa. The 8-bands were extracted from the WorldView-2 image, and 24 of the most widely used vegetation indices in estimating grassland biophysical parameters were calculated. The random forest algorithm and forward variable method were applied to identify the optimal variables (WorldView-2 spectral bands, vegetation indices, and a combination of bands and indices) for classifying the species. The random forest algorithm could classify species with an overall accuracy of 82.6% (KHAT[an estimate of κ]=0.76) using six of the WorldView-2 spectral bands and an overall accuracy of 90% (KHAT=0.87) using a subset of vegetation indices (n=9). Three bands selected were located at the new WorldView-2 spectral regions of coastal blue, yellow, and the red-edge. There was no significant improvement in increaser species classification by using a combination of bands and indices. Overall, the study demonstrated the potential of the WorldView-2 data for improving increaser separability at species level.

  12. Discriminating indicator grass species for rangeland degradation assessment using hyperspectral data resampled to AISA Eagle resolution

    NASA Astrophysics Data System (ADS)

    Mansour, Khalid; Mutanga, Onisimo; Everson, Terry; Adam, Elhadi

    2012-06-01

    The development of techniques to estimate and map increaser grass species is critical for better understanding the condition of the rangeland and levels of rangeland degradation. This paper investigates whether canopy reflectance spectra, resampled to AISA Eagle resolution can discriminate among four increaser species representing different levels of rangeland degradation. Canopy spectral measurements were taken from the four indicator species: Hyparrhenia hirta (HH), Eragrostis curvula (EC), Sporobolus africanus (SA), and Aristida diffusa (AD). The random forest algorithm and a forward variable selection technique were used to identify optimal wavelengths for discriminating the species. Results revealed that the optimal number of wavelengths (n = 8) that yielded the lowest OOB error (11.36%) in discriminating among the four increaser species are located in 966.7, 877.6, 691.9, 718.7, 902.7, 854.8, 674.1 and 703 nm. These wavelengths are located in the visible, red-edge and near-infrared regions of the electromagnetic spectrum. The random forest algorithm can accurately discriminate species with an overall accuracy of 88.64% and a KHAT value of 0.85. The study demonstrated the possibility to upscale the method to airborne sensors such as AISA Eagle for mapping indicator species of rangeland degradation. A rotational grazing management plan should be considered as a way to create sustainable rangeland management in degraded areas.

  13. Preliminary Insights into the Phylogeography of Six Aquatic Hyphomycete Species

    PubMed Central

    Duarte, Sofia; Seena, Sahadevan; Bärlocher, Felix; Cássio, Fernanda; Pascoal, Cláudia

    2012-01-01

    Aquatic hyphomycetes occur worldwide on a wide range of plant substrates decomposing in freshwaters, and are known to play a key role in organic matter turnover. The presumed worldwide distribution of many aquatic hyphomycete species has been based on morphology-based taxonomy and identification, which may overlook cryptic species, and mask global-scale biogeographical patterns. This might be circumvented by using DNA sequence data. The internal transcribed spacer (ITS) region from rDNA was recently designated as the most suitable barcode for fungal identification. In this study, we generated ITS barcodes of 130 isolates belonging to 6 aquatic hyphomycete species (Anguillospora filiformis, Flagellospora penicillioides, Geniculospora grandis, Lunulospora curvula, Tetrachaetum elegans and Tricladium chaetocladium), and collected from streams of Southwest Europe (86 isolates) and East Australia (44 isolates). European and Australian populations of 4 species (A. filiformis, F. penicillioides, G. grandis and T. elegans) grouped into different clades, and molecular diversity indices supported significant differentiation. Continents did not share haplotypes, except for T. chaetocladium. Overall results show substantial population diversity for all tested species and suggests that the biogeography of aquatic hyphomycetes may be species-specific. PMID:23028909

  14. New species of Solanum (Solanaceae) from Peru and Ecuador

    PubMed Central

    Knapp, Sandra

    2010-01-01

    Abstract Three new species of “non-spiny" Solanum are described from Peru and Ecuador, and a revised description for Solanum verecundum M. Nee is presented. Solanum kulliwaita S. Knapp, sp. nov. (Dulcamaroid clade) is endemic to the Department of Cuzco in southern Peru, and is most similar to the recently described Solanum sanchez-vegae S. Knapp of northern Peru. Solanum dillonii S. Knapp, sp. nov. (Brevantherum clade) is found in southern Ecuador and northern Peru in the Amotape-Huancabamba phytogeographic zone, and is morphologically similar to the widespread Solanum riparium Ruiz & Pav. Solanum oxapampense S. Knapp, sp. nov., (also of the Brevantherum clade) is endemic to the Oxapampa region (Department of Pasco) of central Peru, and is similar to and segregated from Solanum verecundum M. Nee of Peru and Ecuador. Complete descriptions, distributions and preliminary conservation assessments of all new species are given. PMID:22171167

  15. Effect of selected antiasthmatic plant constituents against micro organism causing upper respiratory tract infection.

    PubMed

    Nilani, P; Duraisamy, B; Dhamodaran, P; Ravichandran, S; Elango, K

    2010-01-01

    Most exacerbations of asthma can be proven to be associated with bacterial infections and there is scientific evidence that frequent respiratory infections particularly bacterial infections provoke asthma attack. Considering these facts different plant extracts and phytoconstituents with proven anti asthmatic property had been selected for screening anti microbial activity in in-vitro models. In the present study, Coleus forskohlii Willd. extract (10% Forskolin), Piper Longum L. Extract (20% Piperine), Adathoda vasica Nees. extract (30% Vasicinone), Curcuma longa L. extract (60% Curcumin) were screened for the antibacterial activity against human pathogens causing upper respiratory infection namely Haemophilus influenzae , Streptococcus pneumoniae , Streptococcus pyrogene and Staphylococcus aureus, by taking Gentamycin, Optochin, Bacitracin and Amoxicillin as reference standards. Except for Adathoda vasica Nees. extract, all the other selected plant extracts exhibited a moderate activity antibacterial activity against selected strains.

  16. Two new non-spiny Solanum species from the Bolivian Andes (Morelloid Clade)

    PubMed Central

    Särkinen, Tiina; Knapp, Sandra; Nee, Michael

    2015-01-01

    Abstract Two new Bolivian species are described from the Morelloid clade of Solanum (section Solanum in the traditional sense). Solanum alliariifolium M.Nee & Särkinen, sp. nov. is found in montane forests between 1,900 and 3,200 m and is morphologically most similar to Solanum leptocaulon Van Heurck & Müll.Arg., also from montane forests in southern Peru and Bolivia. Solanum rhizomatum Särkinen & M.Nee, sp. nov. is found in seasonally dry forests and matorral vegetation in lower elevations between 1,300 and 2,900 m and is most similar to Solanum pygmaeum Cav., a species native to sub-tropical Argentina but introduced in subtropical and temperate areas worldwide. PMID:25878556

  17. On the potential of the ICOS atmospheric CO2 measurement network for estimating the biogenic CO2 budget of Europe

    NASA Astrophysics Data System (ADS)

    Kadygrov, N.; Broquet, G.; Chevallier, F.; Rivier, L.; Gerbig, C.; Ciais, P.

    2015-11-01

    We present a performance assessment of the European Integrated Carbon Observing System (ICOS) atmospheric network for constraining European biogenic CO2 fluxes (hereafter net ecosystem exchange, NEE). The performance of the network is assessed in terms of uncertainty in the fluxes, using a state-of-the-art mesoscale variational atmospheric inversion system assimilating hourly averages of atmospheric data to solve for NEE at 6 h and 0.5° resolution. The performance of the ICOS atmospheric network is also assessed in terms of uncertainty reduction compared to typical uncertainties in the flux estimates from ecosystem models, which are used as prior information by the inversion. The uncertainty in inverted fluxes is computed for two typical periods representative of northern summer and winter conditions in July and in December 2007, respectively. These computations are based on a observing system simulation experiment (OSSE) framework. We analyzed the uncertainty in a 2-week-mean NEE as a function of the spatial scale with a focus on the model native grid scale (0.5°), the country scale and the European scale (including western Russia and Turkey). Several network configurations, going from 23 to 66 sites, and different configurations of the prior uncertainties and atmospheric model transport errors are tested in order to assess and compare the improvements that can be expected in the future from the extension of the network, from improved prior information or transport models. Assimilating data from 23 sites (a network comparable to present-day capability) with errors estimated from the present prior information and transport models, the uncertainty reduction on a 2-week-mean NEE should range between 20 and 50 % for 0.5° resolution grid cells in the best sampled area encompassing eastern France and western Germany. At the European scale, the prior uncertainty in a 2-week-mean NEE is reduced by 50 % (66 %), down to ~ 43 Tg C month-1 (26 Tg C month-1) in July

  18. Modeling surface roughness scattering in metallic nanowires

    SciTech Connect

    Moors, Kristof; Sorée, Bart; Magnus, Wim

    2015-09-28

    Ando's model provides a rigorous quantum-mechanical framework for electron-surface roughness scattering, based on the detailed roughness structure. We apply this method to metallic nanowires and improve the model introducing surface roughness distribution functions on a finite domain with analytical expressions for the average surface roughness matrix elements. This approach is valid for any roughness size and extends beyond the commonly used Prange-Nee approximation. The resistivity scaling is obtained from the self-consistent relaxation time solution of the Boltzmann transport equation and is compared to Prange-Nee's approach and other known methods. The results show that a substantial drop in resistivity can be obtained for certain diameters by achieving a large momentum gap between Fermi level states with positive and negative momentum in the transport direction.

  19. Variability of annual CO2 exchange from Dutch Grasslands

    NASA Astrophysics Data System (ADS)

    Jacobs, C. M. J.; Jacobs, A. F. G.; Bosveld, F. C.; Hendriks, D. M. D.; Hensen, A.; Kroon, P. S.; Moors, E. J.; Nol, L.; Schrier-Uijl, A.; Veenendaal, E. M.

    2007-05-01

    An intercomparison is made of the Net Ecosystem Exchange of CO2, NEE, for eight Dutch grassland sites; four natural grasslands, two production grasslands and two meteorological stations within a rotational grassland region. At all sites the NEE was determined during at least 10 months per site, using the eddy-covariance (EC) technique, but in different years. The photosynthesis-light response analysis technique is used along with the respiration-temperature response technique to partition NEE among Gross Primary Production (GPP) and Ecosystem Respiration (Re) and to obtain the eco-physiological characteristics of the sites at the field scale. Annual sums of NEE, GPP and Re are then estimated using the fitted response curves with observed radiation and air temperature from a meteorological site in the centre of The Netherlands as drivers. These calculations are carried out for four years (2002-2005). The estimated annual Re for all individual sites is more or less constant per site and the average for all sites amounts to 1390±30 gC m-2 a-1. The narrow uncertainty band (±2%) reflects the small differences in the mean annual air temperature. The mean annual GPP was estimated to be 1325 g C m-2 a-1, and displays a much higher standard deviation, of ±100 gC m-2 a-1 (8%), which reflects the relatively large variation in annual solar radiation. The mean annual NEE amounts to -65±85 gC m-2 a-1, which implies that on average the grasslands act as a source, with a relatively large standard deviation. From two sites, four-year records of CO2 flux were available and analyzed (2002-2005). Using the weather record of 2005 with optimizations from the other years, standard deviation of annual GPP was estimated to be 171-206 gC m-2 a-1 (8-14%), of annual Re 227-247 gC m-2 a-1 (14-16%) and of annual NEE 176-276 gC m-2 a-1. The inter-site standard deviation was higher for GPP and Re, 534 gC m-2 a-1 (37.3%) and 486 gC m-2 a-1 (34.8%), respectively. However, the inter

  20. The Aquatic Communities Inhabiting Internodes of Two Sympatric Bamboos in Argentinean Subtropical Forest

    PubMed Central

    Campos, Raúl E.

    2013-01-01

    In order to determine if phytotelmata in sympatric bamboos of the genus Guadua might be colonized by different types of arthropods and contain communities of different complexities, the following objectives were formulated: (1) to analyze the structure and species richness of the aquatic macroinvertebrate communities, (2) to comparatively analyze co-occurrences; and (3) to identify the main predators. Field studies were conducted in a subtropical forest in Argentina, where 80 water-filled bamboo internodes of Guadua chacoensis (Rojas Acosta) Londoño and Peterson (Poales: Poaceae) and G. trinii (Nees) Nees and Rupr. were sampled. Morphological measurements indicated that G. chacoensis held more fluid than G. trinii. The communities differed between Guadua species, but many macroinvertebrate species used both bamboo species. The phytotelmata were mainly colonized by Diptera of the families Culicidae and Ceratopogonidae. PMID:24224775

  1. Optimizing Photosynthetic and Respiratory Parameters Based on the Seasonal Variation Pattern in Regional Net Ecosystem Productivity Obtained from Atmospheric Inversion

    NASA Astrophysics Data System (ADS)

    Chen, Z.; Chen, J.; Zheng, X.; Jiang, F.; Zhang, S.; Ju, W.; Yuan, W.; Mo, G.

    2014-12-01

    In this study, we explore the feasibility of optimizing ecosystem photosynthetic and respiratory parameters from the seasonal variation pattern of the net carbon flux. An optimization scheme is proposed to estimate two key parameters (Vcmax and Q10) by exploiting the seasonal variation in the net ecosystem carbon flux retrieved by an atmospheric inversion system. This scheme is implemented to estimate Vcmax and Q10 of the Boreal Ecosystem Productivity Simulator (BEPS) to improve its NEP simulation in the Boreal North America (BNA) region. Simultaneously, in-situ NEE observations at six eddy covariance sites are used to evaluate the NEE simulations. The results show that the performance of the optimized BEPS is superior to that of the BEPS with the default parameter values. These results have the implication on using atmospheric CO2 data for optimizing ecosystem parameters through atmospheric inversion or data assimilation techniques.

  2. Soliton-like solutions for a (2+1) -dimensional nonintegrable KdV equation and a variable-coefficient KdV equation

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Li, B.

    2003-08-01

    Based on a Riccati equation and a symbolic computation system--Maple, a generalized Riccati equation expansion method is presented for constructing soliton-like solutions and periodic form solutions for some nonlinear evolution equations (NEEs) or NEEs with variable coefficients. Compared with most of the existing tanh methods, the extended tanh-function method, the modified extended tanh-function method and the generalized hyperbolic-function method, the proposed method is more powerful. We study a (2+1)-dimensional general nonintegrable KdV equation, a KdV equation with variable coefficients. As a result, rich new families of exact solutions, including the non-travelling wave's and coefficient functions' soliton-like solutions, singular soliton-like solutions, periodic form solutions, are obtained. When setting the arbitrary functions in some solutions be equal to special constants or special functions, the solitary wave solutions can be recovered.

  3. Two new non-spiny Solanum species from the Bolivian Andes (Morelloid Clade).

    PubMed

    Särkinen, Tiina; Knapp, Sandra; Nee, Michael

    2015-01-01

    Two new Bolivian species are described from the Morelloid clade of Solanum (section Solanum in the traditional sense). Solanumalliariifolium M.Nee & Särkinen, sp. nov. is found in montane forests between 1,900 and 3,200 m and is morphologically most similar to Solanumleptocaulon Van Heurck & Müll.Arg., also from montane forests in southern Peru and Bolivia. Solanumrhizomatum Särkinen & M.Nee, sp. nov. is found in seasonally dry forests and matorral vegetation in lower elevations between 1,300 and 2,900 m and is most similar to Solanumpygmaeum Cav., a species native to sub-tropical Argentina but introduced in subtropical and temperate areas worldwide.

  4. Reduced uncertainty of regional scale CLM predictions of net carbon fluxes and leaf area indices with estimated plant-specific parameters

    NASA Astrophysics Data System (ADS)

    Post, Hanna; Hendricks Franssen, Harrie-Jan; Han, Xujun; Baatz, Roland; Montzka, Carsten; Schmidt, Marius; Vereecken, Harry

    2016-04-01

    Reliable estimates of carbon fluxes and states at regional scales are required to reduce uncertainties in regional carbon balance estimates and to support decision making in environmental politics. In this work the Community Land Model version 4.5 (CLM4.5-BGC) was applied at a high spatial resolution (1 km2) for the Rur catchment in western Germany. In order to improve the model-data consistency of net ecosystem exchange (NEE) and leaf area index (LAI) for this study area, five plant functional type (PFT)-specific CLM4.5-BGC parameters were estimated with time series of half-hourly NEE data for one year in 2011/2012, using the DiffeRential Evolution Adaptive Metropolis (DREAM) algorithm, a Markov Chain Monte Carlo (MCMC) approach. The parameters were estimated separately for four different plant functional types (needleleaf evergreen temperate tree, broadleaf deciduous temperate tree, C3-grass and C3-crop) at four different sites. The four sites are located inside or close to the Rur catchment. We evaluated modeled NEE for one year in 2012/2013 with NEE measured at seven eddy covariance sites in the catchment, including the four parameter estimation sites. Modeled LAI was evaluated by means of LAI derived from remotely sensed RapidEye images of about 18 days in 2011/2012. Performance indices were based on a comparison between measurements and (i) a reference run with CLM default parameters, and (ii) a 60 instance CLM ensemble with parameters sampled from the DREAM posterior probability density functions (pdfs). The difference between the observed and simulated NEE sum reduced 23% if estimated parameters instead of default parameters were used as input. The mean absolute difference between modeled and measured LAI was reduced by 59% on average. Simulated LAI was not only improved in terms of the absolute value but in some cases also in terms of the timing (beginning of vegetation onset), which was directly related to a substantial improvement of the NEE estimates in

  5. Analytical studies on the LAOS behaviors of some popularly used viscoelastic constitutive equations with a new insight on stress decomposition of normal stresses

    NASA Astrophysics Data System (ADS)

    Bae, Jung-Eun; Cho, Kwang Soo

    2017-09-01

    Shear stress of Large Amplitude Oscillatory Shear (LAOS) is known to be decomposed to elastic and viscous stresses. According to the parity of normal stress with respect to shear strain and shear rate, it also can be mathematically decomposed into two parts: NEE (even symmetry part for both strain and strain rate) and NOO (odd symmetry part for both shear strain and shear rate). However, the physical meaning of the decomposed normal stress is questionable. This paper is to prove the conjecture that NEE is elastic and NOO is viscous under the condition of time-strain separability. For the purpose of the proof, we developed mathematical tools for the analytical solutions of LAOS. We applied the mathematical methods to some popularly used constitutive equations such as the convected Maxwell models, the separable Kaye-Bernstein-Kearsley-Zepas (K-BKZ) model, the Giesekus model, and the Phan-Thien and Tanner model.

  6. Study of the genus Bracon Fabricius, 1804 (Hymenoptera: Braconidae) of Southern Iran with description of a new species.

    PubMed

    Ameri, Ali; Talebi, Ali Asghar; Beyarslan, Ahmet; Kamali, Karim; Rakhshani, Ehsan

    2014-01-16

    A survey on the genus Bracon Fabricius, 1804 was conducted in Hormozgan province, Southern Iran, during February 2011-July 2012. In all, 19 species belonging to seven subgenera were collected and identified, of which seven species and the subgenus Asiabracon Tobias, 1957 are recorded for first time from Iran. Bracon (Orthobracon) persiangulfensis Ameri, Beyarslan & Talebi sp. n. is newly described and illustrated from the Queshm island of Persian Gulf. Morphological characters of the new species were compared with the congeneric species. The newly recorded species from Iran were as follow: B. (Asiabracon) quardrimaculatus Telenga, 1936; B. (Bracon) kozak Telenga, 1936; B. (Glabrobracon) immutator Nees; B. (Habrobracon) telengai (Mulyarskaya, 1955); B. (Habrobracon) variegator Spinola, 1808; B. (Orthobracon) epitriptus Marshall, 1885 and B. (Orthobracon) exhilarator Nees, 1834. A key is presented for identification of Bracon species collected in Hormozgan province as well as an updated checklist of all Bracon species occurring in Iran.

  7. kwayask e-ki-pe-kiskinowapahtihicik = Their Example Showed Me the Way: A Cree Woman's Life Shaped by Two Cultures.

    ERIC Educational Resources Information Center

    Minde, Emma; Ahenakew, Freda, Ed.; Wolfart, H. C., Ed.

    Emma Minde (nee Memnook)was born in 1907 in Saddle Lake, Alberta. In 1927 she was given by her father in an arranged marriage to Joe Minde, who lived in Hobbema, Alberta. In this recorded autobiography taped in 1988 when she was 81 years old, little is said about her parents and her life as a child other than that she spent 7 years at a…

  8. Effects of Pre-industrial and Future Atmospheric CO2 concentration on Net Ecosystem Exchange on Arid and Semi-Arid Ecosystems

    NASA Astrophysics Data System (ADS)

    Kalhori, A. A. M.; Deutschman, D.; Cheng, Y.; Oechel, W. C.

    2014-12-01

    Ecosystem carbon dioxide flux was studied between 1997 and 2000 under six different CO2 concentrations (250 ppm, 350 ppm, 450 ppm, 550 ppm, 650 ppm, and 750 ppm) using CO2 LT (CO2 controlled, naturally Lit, Temperature controlled) null balance chambers in Southern California chaparral dominated by Adenostoma fasciculatum. The purpose of this study is to evaluate possible effects of altered levels of atmospheric CO2 concentrations on carbon fluxes in a natural chaparral ecosystem. Here we present that the increase of CO2 from near pre-industrial levels of around 250 ppm to recent past CO2 levels of 350 ppm are sufficient to increase NEE. These data indicate that chaparral ecosystems will increase carbon sequestration under elevated CO2 levels and that under elevated atmospheric CO2 there will be greater sink or reduced source of ecosystem CO2 to the atmosphere as a result of improved moisture status. The effect of elevated CO2 on increasing NEE was greatest during the warm and dry season versus the cold and wet season. Further, it appears that increasing atmospheric CO2 will have greater relative effects in areas of increasing water stress as CO2 treatment effects on NEE were greater in modestly dry years and with longer periods of drought. The daily maximum NEE difference between the lowest (250 ppm) and the highest (750 ppm) CO2 concentrations treatments for January was -0.127gC m-2 h-1, but for June was -0.267 gC m-2 h-1 in this study, which was a 210 percent increase. The differences between the lower treatments and higher treatments were greater in the later years indicating there was an accumulative effect. Cumulative of net ecosystem exchange (gC m-2) between 1/1/1997 and 1/1/2001 under six different CO2 concentration is presented in the figure attached.

  9. Effects of experimental nitrogen deposition on peatland carbon pools and fluxes: a modelling analysis

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Blodau, C.; Moore, T. R.; Bubier, J.; Juutinen, S.; Larmola, T.

    2015-01-01

    Nitrogen (N) pollution of peatlands alters their carbon (C) balances, yet long-term effects and controls are poorly understood. We applied the model PEATBOG to explore impacts of long-term nitrogen (N) fertilization on C cycling in an ombrotrophic bog. Simulations of summer gross ecosystem production (GEP), ecosystem respiration (ER) and net ecosystem exchange (NEE) were evaluated against 8 years of observations and extrapolated for 80 years to identify potential effects of N fertilization and factors influencing model behaviour. The model successfully simulated moss decline and raised GEP, ER and NEE on fertilized plots. GEP was systematically overestimated in the model compared to the field data due to factors that can be related to differences in vegetation distribution (e.g. shrubs vs. graminoid vegetation) and to high tolerance of vascular plants to N deposition in the model. Model performance regarding the 8-year response of GEP and NEE to N input was improved by introducing an N content threshold shifting the response of photosynthetic capacity (GEPmax) to N content in shrubs and graminoids from positive to negative at high N contents. Such changes also eliminated the competitive advantages of vascular species and led to resilience of mosses in the long-term. Regardless of the large changes of C fluxes over the short-term, the simulated GEP, ER and NEE after 80 years depended on whether a graminoid- or shrub-dominated system evolved. When the peatland remained shrub-Sphagnum-dominated, it shifted to a C source after only 10 years of fertilization at 6.4 g N m-2 yr-1, whereas this was not the case when it became graminoid-dominated. The modelling results thus highlight the importance of ecosystem adaptation and reaction of plant functional types to N deposition, when predicting the future C balance of N-polluted cool temperate bogs.

  10. Effects of experimental nitrogen deposition on peatland carbon pools and fluxes: a modeling analysis

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Blodau, C.; Moore, T. R.; Bubier, J. L.; Juutinen, S.; Larmola, T.

    2014-07-01

    Nitrogen (N) pollution of peatlands alters their carbon (C) balances, yet long-term effects and controls are poorly understood. We applied the model PEATBOG to analyze impacts of long-term nitrogen (N) fertilization on C cycling in an ombrotrophic bog. Simulations of summer gross ecosystem production (GEP), ecosystem respiration (ER) and net ecosystem exchange (NEE) were evaluated against 8 years of observations and extrapolated for 80 years to identify potential effects of N fertilization and factors influencing model behavior. The model successfully simulated moss decline and raised GEP, ER and NEE on fertilized plots. GEP was systematically overestimated in the model compared to the field data due to high tolerance of Sphagnum to N deposition in the model. Model performance regarding the 8 year response of GEP and NEE to N was improved by introducing an N content threshold shifting the response of photosynthesis capacity to N content in shrubs and graminoids from positive to negative at high N contents. Such changes also eliminated the competitive advantages of vascular species and led to resilience of mosses in the long-term. Regardless of the large changes of C fluxes over the short-term, the simulated GEP, ER and NEE after 80 years depended on whether a graminoid- or shrub-dominated system evolved. When the peatland remained shrub-Sphagnum dominated, it shifted to a C source after only 10 years of fertilization at 6.4 g N m-2 yr-1, whereas this was not the case when it became graminoid-dominated. The modeling results thus highlight the importance of ecosystem adaptation and reaction of plant functional types to N deposition, when predicting the future C balance of N-polluted cool temperate bogs.

  11. Electrodiagnostic approach to patients with weakness.

    PubMed

    Dillingham, Timothy R

    2003-05-01

    Electrodiagnosis has a key role in the evaluation of patients presenting with weakness. The electrodiagnostician should maintain a broad inclusive differential diagnosis and tailor the examination using a sound conceptual framework. A clear understanding of what is normal provides the proper foundation upon which to judge electrodiagnostic findings. Many peripheral neuromuscular conditions manifest themselves in characteristic ways on NEE and nerve conduction testing, making them identifiable to the skilled electrodiagnostic medicine consultant.

  12. The Way the Wind Blows Matters to Ecosystem Water Use Efficiency

    NASA Astrophysics Data System (ADS)

    Montaldo, N.; Oren, R.

    2015-12-01

    In many regions, atmospheric conditions change frequently with shifts of wind direction, extending maritime influences far inland or continental influences to coastal ecosystems. Climate models predict changes in both wind direction and velocity; these changes could potentially impact ecosystems mass and energy exchanges with the atmosphere. Using climate and ecosystem-scale eddy-covariance data from Sardinia, we evaluated whether the frequency of certain wind characteristics, potentially improving ecosystem CO2 uptake, have changed over five decades, and whether these characteristics are indeed linked to ecosystem gas-exchange responses of the studied ecosystem. The analyses shows that days dominated by summer Mistral winds decreased on average 3% per decade, and that wind direction affects biosphere-atmosphere exchange of carbon but not water. High velocity cool Mistral winds from continental Europe treble vapor pressure deficit (D) as they cross the island. In contrast, arriving with a similar D, lower velocity, warmer Saharan Sirocco winds heat up, thus increasing D five-fold only 50 km inland. Over a mixed ecosystem (grass-wild olive), while soil moisture was low and constant, daytime net carbon exchange (NEE) averaged 2.3-fold higher in Mistral than Sirocco days, largely reflecting the theoretically expected response of canopy conductance (gc) to variation of D. Because the product of gc and D encodes the key ecosystem compensatory mechanism, the reciprocal gc-D response maintained similar ecosystem evapotranspiration (E). Thus, summertime ecosystem water-use efficiency (W=NEE/E), was ~66% higher during Mistral than other days. The historical decrease of Mistral frequency reduced the estimated summertime NEE >30 %. The analyses demonstrate that alteration of dominance of air masses predicted with future climate will amplify or negate the positive effect of increased atmospheric [CO2] on W, and should be considered when assessing climate change impact on NEE.

  13. Assessment of DoD Job Skill Enhancement Programs.

    DTIC Science & Technology

    1991-03-01

    ru(pon., irnducng the Onto for rew-ovng insatca so . searchitg *,WONg data sources. 9gatnng and mantaining Ole data nees and -rompi.ng and r-v ng Ol...that dealt only with military-specific equipment or procedures, course management tools without accompanying training packages, and non-training...November-December, 14-23. U.S. Congress, Office of Technology Assessment (1989). Power on! New tools for teaching and learning. (No. OTA-SET-379

  14. Carbon Sequestration at United States Marine Corps Installations West

    DTIC Science & Technology

    2014-05-20

    levels that inhibit leaf stomatal conductance (e.g., Oren 1993; Bunce et al. 1984; Körner 1994) and photosynthesis (Arnone et al. 2008). It appears that...layers of the soil, stimulating Rh more than plant photosynthesis . The larger negative NEE values (net CO2 uptake) and faster accumulation of ecosystem...C sequestration values because of a greater stimulation of plant photosynthesis . Results indicate that arid shrublands similar to those found at

  15. Reconciling estimates of the contemporary North American carbon balance among terrestrial biosphere models, atmospheric inversions, and a new approach for estimating net ecosystem exchange from inventory-based data

    USGS Publications Warehouse

    Hayes, Daniel J.; Turner, David P.; Stinson, Graham; McGuire, A. David; Wei, Yaxing; West, Tristram O.; Heath, Linda S.; de Jong, Bernardus; McConkey, Brian G.; Birdsey, Richard A.; Kurz, Werner A.; Jacobson, Andrew R.; Huntzinger, Deborah N.; Pan, Yude; Post, W. Mac; Cook, Robert B.

    2012-01-01

    We develop an approach for estimating net ecosystem exchange (NEE) using inventory-based information over North America (NA) for a recent 7-year period (ca. 2000–2006). The approach notably retains information on the spatial distribution of NEE, or the vertical exchange between land and atmosphere of all non-fossil fuel sources and sinks of CO2, while accounting for lateral transfers of forest and crop products as well as their eventual emissions. The total NEE estimate of a -327 ± 252 TgC yr-1 sink for NA was driven primarily by CO2 uptake in the Forest Lands sector (-248 TgC yr-1), largely in the Northwest and Southeast regions of the US, and in the Crop Lands sector (-297 TgC yr-1), predominantly in the Midwest US states. These sinks are counteracted by the carbon source estimated for the Other Lands sector (+218 TgC yr-1), where much of the forest and crop products are assumed to be returned to the atmosphere (through livestock and human consumption). The ecosystems of Mexico are estimated to be a small net source (+18 TgC yr-1) due to land use change between 1993 and 2002. We compare these inventory-based estimates with results from a suite of terrestrial biosphere and atmospheric inversion models, where the mean continental-scale NEE estimate for each ensemble is -511 TgC yr-1 and -931 TgC yr-1, respectively. In the modeling approaches, all sectors, including Other Lands, were generally estimated to be a carbon sink, driven in part by assumed CO2 fertilization and/or lack of consideration of carbon sources from disturbances and product emissions. Additional fluxes not measured by the inventories, although highly uncertain, could add an additional -239 TgC yr-1 to the inventory-based NA sink estimate, thus suggesting some convergence with the modeling approaches.

  16. Adaptive data-driven models for estimating carbon fluxes in the Northern Great Plains

    USGS Publications Warehouse

    Wylie, B.K.; Fosnight, E.A.; Gilmanov, T.G.; Frank, A.B.; Morgan, J.A.; Haferkamp, Marshall R.; Meyers, T.P.

    2007-01-01

    Rangeland carbon fluxes are highly variable in both space and time. Given the expansive areas of rangelands, how rangelands respond to climatic variation, management, and soil potential is important to understanding carbon dynamics. Rangeland carbon fluxes associated with Net Ecosystem Exchange (NEE) were measured from multiple year data sets at five flux tower locations in the Northern Great Plains. These flux tower measurements were combined with 1-km2 spatial data sets of Photosynthetically Active Radiation (PAR), Normalized Difference Vegetation Index (NDVI), temperature, precipitation, seasonal NDVI metrics, and soil characteristics. Flux tower measurements were used to train and select variables for a rule-based piece-wise regression model. The accuracy and stability of the model were assessed through random cross-validation and cross-validation by site and year. Estimates of NEE were produced for each 10-day period during each growing season from 1998 to 2001. Growing season carbon flux estimates were combined with winter flux estimates to derive and map annual estimates of NEE. The rule-based piece-wise regression model is a dynamic, adaptive model that captures the relationships of the spatial data to NEE as conditions evolve throughout the growing season. The carbon dynamics in the Northern Great Plains proved to be in near equilibrium, serving as a small carbon sink in 1999 and as a small carbon source in 1998, 2000, and 2001. Patterns of carbon sinks and sources are very complex, with the carbon dynamics tilting toward sources in the drier west and toward sinks in the east and near the mountains in the extreme west. Significant local variability exists, which initial investigations suggest are likely related to local climate variability, soil properties, and management.

  17. Twelve year interannual and seasonal variability of stream carbon export from a boreal peatland catchment

    NASA Astrophysics Data System (ADS)

    Leach, J. A.; Larsson, A.; Wallin, M. B.; Nilsson, M. B.; Laudon, H.

    2016-07-01

    Understanding stream carbon export dynamics is needed to accurately predict how the carbon balance of peatland catchments will respond to climatic and environmental change. We used a 12 year record (2003-2014) of continuous streamflow and manual spot measurements of total organic carbon (TOC), dissolved inorganic carbon (DIC), methane (CH4), and organic carbon quality (carbon-specific ultraviolet absorbance at 254 nm per dissolved organic carbon) to assess interannual and seasonal variability in stream carbon export for a peatland catchment (70% mire and 30% forest cover) in northern Sweden. Mean annual total carbon export for the 12 year period was 12.2 gCm-2 yr-1, but individual years ranged between 6 and 18 gCm-2 yr-1. TOC, which was primarily composed of dissolved organic carbon (>99%), was the dominant form of carbon being exported, comprising 63% to 79% of total annual exports, and DIC contributed between 19% and 33%. CH4 made up less than 5% of total export. When compared to previously published annual net ecosystem exchange (NEE) for the studied peatland system, stream carbon export typically accounted for 12 to 50% of NEE for most years. However, in 2006 stream carbon export accounted for 63 to 90% (estimated uncertainty range) of NEE due to a dry summer which suppressed NEE, followed by a wet autumn that resulted in considerable stream export. Runoff exerted a primary control on stream carbon export from this catchment; however, our findings suggest that seasonal variations in biologic and hydrologic processes responsible for production and transport of carbon within the peatland were secondary influences on stream carbon export. Consideration of these seasonal dynamics is needed when predicting stream carbon export response to environmental change.

  18. Predicting landscape-scale CO2 flux at a pasture and rice paddy with long-term hyperspectral canopy reflectance measurements

    NASA Astrophysics Data System (ADS)

    Matthes, J. H.; Knox, S. H.; Sturtevant, C.; Sonnentag, O.; Verfaillie, J.; Baldocchi, D.

    2015-08-01

    Measurements of hyperspectral canopy reflectance provide a detailed snapshot of information regarding canopy biochemistry, structure and physiology. In this study, we collected 5 years of repeated canopy hyperspectral reflectance measurements for a total of over 100 site visits within the flux footprints of two eddy covariance towers at a pasture and rice paddy in northern California. The vegetation at both sites exhibited dynamic phenology, with significant interannual variability in the timing of seasonal patterns that propagated into interannual variability in measured hyperspectral reflectance. We used partial least-squares regression (PLSR) modeling to leverage the information contained within the entire canopy reflectance spectra (400-900 nm) in order to investigate questions regarding the connection between measured hyperspectral reflectance and landscape-scale fluxes of net ecosystem exchange (NEE) and gross primary productivity (GPP) across multiple timescales, from instantaneous flux to monthly integrated flux. With the PLSR models developed from this large data set we achieved a high level of predictability for both NEE and GPP flux in these two ecosystems, where the R2 of prediction with an independent validation data set ranged from 0.24 to 0.69. The PLSR models achieved the highest skill at predicting the integrated GPP flux for the week prior to the hyperspectral canopy reflectance collection, whereas the NEE flux often achieved the same high predictive power at daily to monthly integrated flux timescales. The high level of predictability achieved by PLSR in this study demonstrated the potential for using repeated hyperspectral canopy reflectance measurements to help partition NEE into its component fluxes, GPP and ecosystem respiration, and for using quasi-continuous hyperspectral reflectance measurements to model regional carbon flux in future analyses.

  19. Predicting landscape-scale CO2 flux at a pasture and rice paddy with long-term hyperspectral canopy reflectance measurements

    NASA Astrophysics Data System (ADS)

    Matthes, J. H.; Knox, S. H.; Sturtevant, C.; Sonnentag, O.; Verfaillie, J.; Baldocchi, D.

    2015-03-01

    Measurements of hyperspectral canopy reflectance provide a detailed snapshot of information regarding canopy biochemistry, structure and physiology. In this study, we collected five years of repeated canopy hyperspectral reflectance measurements for a total of over 100 site visits within the flux footprints of two eddy covariance towers at a pasture and rice paddy in Northern California. The vegetation at both sites exhibited dynamic phenology, with significant inter-annual variability in the timing of seasonal patterns that propagated into inter-annual variability in measured hyperspectral reflectance. We used partial least-squares regression (PLSR) modeling to leverage the information contained within the entire continuous canopy reflectance spectra (400-900 nm) in order to investigate questions regarding the connection between measured hyperspectral reflectance and landscape-scale fluxes of net ecosystem exchange (NEE) and gross primary productivity (GPP) across multiple timescales, from instantaneous flux to monthly-integrated flux. With the PLSR models developed from this large dataset we achieved a high level of predictability for both NEE and GPP flux in these two ecosystems, where the R2 of prediction with an independent validation dataset ranged from 0.24 to 0.69. The PLSR models achieved the highest skill at predicting the integrated GPP flux for the week prior to the hyperspectral canopy reflectance collection, whereas the NEE flux often achieved the same high predictive power at the daily- through monthly-integrated flux timescales. The high level of predictability achieved by PLSR regression in this study demonstrated the potential for using repeated hyperspectral canopy reflectance measurements to help partition NEE measurements into its component fluxes, GPP and ecosystem respiration, and for using continuous hyperspectral reflectance measurements to model regional carbon flux in future analyses.

  20. Block Plan Construction from a Deltahedron Based Adjacency Graph.

    DTIC Science & Technology

    1986-01-01

    shown below: - Assiston ’rofessor of Industria En neeDate Industrial Engineering * y* ACKNOWLEDGEMENTS I would like to thank Dr. John W. Giffin for his...was written in BASICA on an IBM Personal Computer. Due to the amount of memoru available in BASICA , the problem size is somewhat limited however; 11...Figure 4.13. Example III Block Plan with 3 facilities not included To provide a complete block plan, the BREAK feature of BASICA is used. Before

  1. Handbook of the Statistics of Various Terrain and Water (Ice) Backgrounds from Selected U.S. Locations

    DTIC Science & Technology

    1980-01-01

    operations necessary for the successful completion of the analyses. Dr. J. Robert Maxwell was the initial Project Manager and has contributed invaluably to...the histograms provide estimates of how the detection probability and false alarm rate vary with threshold setting. However, today there is a nee.d for...alarm rates V iwith today’s sensor and processor technology. The statistics developed are the probabilities that regions (of various sizes, shapes, and

  2. Implementation of the Department of Defense Small Business Innovation Research Commercialization Pilot Program: Be All You Can Be?

    DTIC Science & Technology

    2011-04-30

    and Related SBIR/STTR Reforms: Be All You Can Be? Prof . Max V. Kidalov, J.D., LL.M., Naval Postgraduate School, Monterey, CA Kevin Hettinger...bilit t f t ll h t i po c an nee s e a y o ore e w a s going to happen tomorrow, next week, next month and next year And to have the ability, . afterwards to explain why it didn’t happen.” – Sir Winston Churchill 47

  3. Implementation of DOD SBIR Commercialization Pilot Program and Related SBIR/STTR Reforms: Be All You Can Be?

    DTIC Science & Technology

    2011-05-12

    Implementation of DOD SBIR Commercialization Pilot Program and Related SBIR/STTR Reforms: Be All You Can Be? Prof . Max V. Kidalov, J.D...an nee s e a y o ore el w a s going to happen tomorrow, next week, next month and next year And to have the ability, . afterwards to explain why it didn’t happen.” – Sir Winston Churchill 47

  4. Dynamic Models Including Uncertainty

    DTIC Science & Technology

    2009-01-22

    least in part with this grant) • H.T. Banks, Prof ., North Carolina State University • G. M. Kepler, Res. Assoc, North Carolina State University • S...8217W- C -( ( »II 2 »P] i=i i’=i - N m nEE d 2{a2p) 2tttid^y ’tax dei N N EE WP) (4.19) 4.2.9 Finite Difference Scheme for Fokker

  5. Evaluating the Significance of CDK2-PELP1 Axis in Tumorigenesis and Hormone Therapy Resistance

    DTIC Science & Technology

    2011-02-01

    Rambabu Challa1, Bramanandam Manavathi3, nee Yew2, Rakesh Kumar4, Rajeshwar Rao Tekmal1, and Ratna K. Vadlamudi1ract Estr influen recept cancer genesi the...coregulator PELP1/MNAR. Nucl Recept Signal 7;5:e004. jhans R, Nair S, Holden AH, Kumar R, Tekmal RR, Vadlamudi RK. cogenic potential of the nuclear...done to elucidate the role of ILK1 in metastatic prostate, cervical and endometrial cancers. A recent study using prostate cancer cell lines

  6. A downward CO2 flux seems to have nowhere to go

    NASA Astrophysics Data System (ADS)

    Ma, J.; Liu, R.; Tang, L.-S.; Lan, Z.-D.; Li, Y.

    2014-11-01

    Recent studies have suggested that deserts, which are a long-neglected region in global carbon budgeting, have strong downward CO2 fluxes and might be a significant carbon sink. This finding, however, has been strongly challenged because neither the reliability of the flux measurements nor the exact location of the fixed carbon has been determined. This paper shows, with a full chain of evidence, that there is indeed strong carbon flux into saline/alkaline land in arid regions. Based on continuous measurement of net ecosystem CO2 exchange (NEE) from 2002 to 2012 (except for 2003), the saline desert in western China was a carbon sink for 9 out of 10 years, and the average yearly NEE for the 10 years was -25.00 ± 12.70 g C m-2 year-1. Supporting evidence for the validity of these NEE estimates comes from the close agreement of NEE values obtained from the chamber and eddy-covariance methods. After ruling out the possibility of changes in C stored in plant biomass or soils, the C uptake was found to be leached downwards into the groundwater body in the process of groundwater fluctuation: rising groundwater absorbs soil dissolved inorganic carbon (DIC), and falling groundwater transports the DIC downward. Horizontal groundwater flow may send this DIC farther away and prevent it from being observed locally. This process has been called "passive leaching" of DIC, in comparison with the active DIC leaching that occurs during groundwater recharge. This passive leaching significantly expands the area where DIC leaching occurs and creates a literally "hidden" carbon sink process under the desert. This study tells us that when a downward CO2 flux is observed, but seems to have nowhere to go, it does not necessarily mean that the flux measurement is unreliable. By looking deeper and farther away, a place and a process may be found "hidden" underground.

  7. Parametric Blade Study Test Report Rotor Configuration. Number 2

    DTIC Science & Technology

    1988-11-01

    by block number) FIELD GROUP SUB. GR. Axial compressor 01 -Gas Turbine t Aircraft Turbine Engine . 19, BSTRACT (Continue on reverse if nee..ary and...AFWAL-TR-88-41108 00 PARAMETRIC BLADE STUDY TEST REPORT 00 ROTOR CONFIGURATION NO. 2 N C. Herbert Law Steven L. Puterbaugh Technology Branch Turbine ...Technology Branch Technology Branch Turbine Engine Division FOR THE COMMANDER THOMAS J. IMS, Director Turbinengine Division Aero P opulsion Laboratory If

  8. Atmospheric observations inform CO2 flux responses to enviroclimatic drivers

    NASA Astrophysics Data System (ADS)

    Fang, Yuanyuan; Michalak, Anna M.

    2015-05-01

    Understanding the response of the terrestrial biospheric carbon cycle to variability in enviroclimatic drivers is critical for predicting climate-carbon interactions. Here we apply an atmospheric-inversion-based framework to assess the relationships between the spatiotemporal patterns of net ecosystem CO2 exchange (NEE) and those of enviroclimatic drivers. We show that those relationships can be directly observed at 1° × 1° 3-hourly resolution from atmospheric CO2 measurements for four of seven large biomes in North America, namely, (i) boreal forests and taiga; (ii) temperate coniferous forests; (iii) temperate grasslands, savannas, and shrublands; and (iv) temperate broadleaf and mixed forests. We find that shortwave radiation plays a dominant role during the growing season over all four biomes. Specific humidity and precipitation also play key roles and are associated with decreased CO2 uptake (or increased release). The explanatory power of specific humidity is especially strong during transition seasons, while that of precipitation appears during both the growing and dormant seasons. We further find that the ability of four prototypical terrestrial biospheric models (TBMs) to represent the spatiotemporal variability of NEE improves as the influence of radiation becomes more dominant, implying that TBMs have a better skill in representing the impact of radiation relative to other drivers. Even so, we show that TBMs underestimate the strength of the relationship to radiation and do not fully capture its seasonality. Furthermore, the TBMs appear to misrepresent the relationship to precipitation and specific humidity at the examined scales, with relationships that are not consistent in terms of sign, seasonality, or significance relative to observations. More broadly, we demonstrate the feasibility of directly probing relationships between NEE and enviroclimatic drivers at scales with no direct measurements of NEE, opening the door to the study of emergent

  9. Upscaling key ecosystem functions across the conterminous United States by a water‐centric ecosystem model

    Treesearch

    Ge Sun; Peter Caldwell; Asko Noormets; Steven G. McNulty; Erika Cohen; al. et.

    2011-01-01

    We developed a water‐centric monthly scale simulation model (WaSSI‐C) by integrating empirical water and carbon flux measurements from the FLUXNET network and an existing water supply and demand accounting model (WaSSI). The WaSSI‐C model was evaluated with basin‐scale evapotranspiration (ET), gross ecosystem productivity (GEP), and net ecosystem exchange (NEE)...

  10. Rain events decrease boreal peatland net CO2 uptake through reduced light availability.

    PubMed

    Nijp, Jelmer J; Limpens, Juul; Metselaar, Klaas; Peichl, Matthias; Nilsson, Mats B; van der Zee, Sjoerd E A T M; Berendse, Frank

    2015-06-01

    Boreal peatlands store large amounts of carbon, reflecting their important role in the global carbon cycle. The short-term exchange and the long-term storage of atmospheric carbon dioxide (CO2 ) in these ecosystems are closely associated with the permanently wet surface conditions and are susceptible to drought. Especially, the single most important peat forming plant genus, Sphagnum, depends heavily on surface wetness for its primary production. Changes in rainfall patterns are expected to affect surface wetness, but how this transient rewetting affects net ecosystem exchange of CO2 (NEE) remains unknown. This study explores how the timing and characteristics of rain events during photosynthetic active periods, that is daytime, affect peatland NEE and whether rain event associated changes in environmental conditions modify this response (e.g. water table, radiation, vapour pressure deficit, temperature). We analysed an 11-year time series of half-hourly eddy covariance and meteorological measurements from Degerö Stormyr, a boreal peatland in northern Sweden. Our results show that daytime rain events systematically decreased the sink strength of peatlands for atmospheric CO2 . The decrease was best explained by rain associated reduction in light, rather than by rain characteristics or drought length. An average daytime growing season rain event reduced net ecosystem CO2 uptake by 0.23-0.54 gC m(-2) . On an annual basis, this reduction of net CO2 uptake corresponds to 24% of the annual net CO2 uptake (NEE) of the study site, equivalent to a 4.4% reduction of gross primary production (GPP) during the growing season. We conclude that reduced light availability associated with rain events is more important in explaining the NEE response to rain events than rain characteristics and changes in water availability. This suggests that peatland CO2 uptake is highly sensitive to changes in cloud cover formation and to altered rainfall regimes, a process hitherto largely

  11. Combining multiple ecosystem productivity measurements to constrain carbon uptake estimates in semiarid grasslands and shrublands

    NASA Astrophysics Data System (ADS)

    Maurer, G. E.; Krofcheck, D. J.; Collins, S. L.; Litvak, M. E.

    2016-12-01

    Recent observational and modeling studies have indicated that semiarid ecosystems are more dynamic contributors to the global carbon budget than once thought. Semiarid carbon fluxes, however, are generally small, with high interannual and spatial variability, which suggests that validating their global significance may depend on examining multiple productivity measures and their associated uncertainties and inconsistencies. We examined ecosystem productivity from eddy covariance (NEE), harvest (NPP), and terrestrial biome models (NEPm) at two very similar grassland sites and one creosote shrubland site in the Sevilleta National Wildlife Refuge of central New Mexico, USA. Our goal was to assess site and methodological correspondence in annual carbon uptake, patterns of interannual variability, and measurement uncertainty. One grassland site was a perennial carbon source losing 30 g C m-2 per year on average, while the other two sites were carbon sources or sinks depending on the year, with average net uptake of 5 and 25 g C m-2 per year at the grassland and shrubland site, respectively. Uncertainty values for cumulative annual NEE overlapped between the three sites in most years. When combined, aboveground and belowground annual NPP measurements were 15% higher than annual NEE values and did not confirm a loss of carbon at any site in any year. Despite differences in mean site carbon balance, year-to-year changes in cumulative annual NEE and NPP were similar at all sites with years 2010 and 2013 being favorable for carbon uptake and 2011 and 2012 being unfavorable at all sites. Modeled NEPm data for a number of nearby grid cells reproduced only a fraction of the observed range in carbon uptake and its interannual variability. These three sites are highly similar in location and climate and multiple carbon flux measurements confirm the high interannual variability in carbon flux. The exact magnitude of these fluxes, however, remains difficult to discern.

  12. Intra-seasonal mapping of CO2 flux in rangelands of northern Kazakhstan at one-kilometer resolution

    USGS Publications Warehouse

    Wylie, B.K.; Gilmanov, T.G.; Johnson, D.A.; Saliendra, Nicanor Z.; Akshalov, K.; Tieszen, L.L.; Reed, B.C.; Laca, Emilio

    2004-01-01

    Algorithms that establish relationships between variables obtained through remote sensing and geographic information system (GIS) technologies are needed to allow the scaling up of site-specific CO2 flux measurements to regional levels. We obtained Bowen ratio-energy balance (BREB) flux tower measurements during the growing seasons of 1998-2000 above a grassland steppe in Kazakhstan. These BREB data were analyzed using ecosystem light-curve equations to quantify 10-day CO2 fluxes associated with gross primary production (GPP) and total respiration (R). Remotely sensed, temporally smoothed normalized difference vegetation index (NDVIsm) and environmental variables were used to develop multiple regression models for the mapping of 10-day CO2 fluxes for the Kazakh steppe. Ten-day GPP was estimated (R 2 = 0.72) by day of year (DOY) and NDVIsm, and 10-day R was estimated (R2 = 0.48) with the estimated GPP and estimated 10-day photosynthetically active radiation (PAR). Regression tree analysis estimated 10-day PAR from latitude, NDVIsm, DOY, and precipitation (R2 = 0.81). Fivefold cross-validation indicated that these algorithms were reasonably robust. GPP, R, and resulting net ecosystem exchange (NEE) were mapped for the Kazakh steppe grassland every 10 days and summed to produce regional growing season estimates of GPP, R, and NEE. Estimates of 10-day NEE agreed well with BREB observations in 2000, showing a slight underestimation in the late summer. Growing season (May to October) mean NEE for Kazakh steppe grasslands was 1.27 Mg C/ha in 2000. Winter flux data were collected during the winter of 2001-2002 and are being analyzed to close the annual carbon budget for the Kazakh steppe. ?? 2004 Springer-Verlag New York, LLC.

  13. Reconciling estimates of the contemporary North American carbon balance among terrestrial biosphere models, atmospheric inversions and a new approach for estimating net ecosystem exchange from inventory-based data

    SciTech Connect

    Hayes, Daniel J; Turner, David P; Stinson, Graham; Mcguire, David; Wei, Yaxing; West, Tristram O.; Heath, Linda S.; De Jong, Bernardus; McConkey, Brian G.; Birdsey, Richard A.; Kurz, Werner; Jacobson, Andrew; Huntzinger, Deborah; Pan, Yude; Post, Wilfred M; Cook, Robert B

    2012-01-01

    We develop an approach for estimating net ecosystem exchange (NEE) using inventory-based information over North America (NA) for a recent 7-year period (ca. 2000 2006). The approach notably retains information on the spatial distribution of NEE, or the vertical exchange between land and atmosphere of all non-fossil fuel sources and sinks of CO2, while accounting for lateral transfers of forest and crop products as well as their eventual emissions. The total NEE estimate of a 327 252 TgC yr1 sink for NA was driven primarily by CO2 uptake in the Forest Lands sector (248 TgC yr1), largely in the Northwest and Southeast regions of the US, and in the Crop Lands sector (297 TgC yr1), predominantly in the Midwest US states. These sinks are counteracted by the carbon source estimated for the Other Lands sector (+218 TgC yr1), where much of the forest and crop products are assumed to be returned to the atmosphere (through livestock and human consumption). The ecosystems of Mexico are estimated tobe a small net source (+18 TgC yr1) due to land use change between 1993 and 2002. We compare these inventorybased estimates with results from a suite of terrestrial biosphere and atmospheric inversion models, where the mean continental-scale NEE estimate for each ensemble is 511 TgC yr1 and 931 TgC yr1, respectively. In the modeling approaches, all sectors, including Other Lands, were generally estimated to be a carbon sink, driven in part by assumed CO2 fertilization and/or lack of consideration of carbon sources from disturbances and product emissions. Additional fluxes not measured by the inventories, although highly uncertain, could add an additional 239 TgC yr1 to the inventory-based NA sink estimate, thus suggesting some convergence with the modeling approaches.

  14. Naval Training Equipment Center Index of Technical Reports,

    DTIC Science & Technology

    1982-09-01

    BETWEEN A VISUAL AND AN AD- 657 472 AUDITORY SIGNAL.MEASUREMENT AD- 657 623 GEOMETRIC FORMS An Equal Discriminability Scale, Aesthetic Preference for...8217L’, :"’ i • I UNCLASSIFIED ATTITUDES(PSYCHOLOGY)/ Navy’s Tactical Aircrew Training AD-AO39 456 Aesthetic frefer nE:e for System (TACTS...RATE OF SPEAKING: I. NATURAL FREQUENCY, DURATION, AND MONITORING METER AS A COMPONENT IN RELATIONSHIP BETWEEN ORIGINAL AND INTENSITY OF VOWELS IN READING

  15. Initial shifts in nitrogen impact on ecosystem carbon fluxes in an alpine meadow: Patterns and causes

    NASA Astrophysics Data System (ADS)

    Song, Bing

    2017-04-01

    It is proposed that rising nitrogen (N) deposition could increase ecosystem net carbon (C) sequestration. However, as a direct measure of ecosystem net C sequestration, how net ecosystem CO2 exchange (NEE) and its different components respond to rising N deposition is still far from clear. Using an N addition gradient experiment (six levels: 0, 2, 4, 8, 16, 32 gN m-2 year-1) in an alpine meadow in the Tibetan Plateau, we explored the responses of different ecosystem C cycle processes to increasing N loading gradient and revealed mechanisms underlying response dynamics. Results showed that NEE, ecosystem respiration (ER), and gross ecosystem production (GEP) all increased linearly with N addition rates in the first year of treatment, but shifted to N saturation responses in the second year with the highest NEE (-7.77 ± 0.48 µmol m-2 s-1) occurring under N addition rate of 8 gN m-2 year-1. The saturation responses of NEE and GEP were caused by N-induced accumulation of standing litter, which limited light availability for plant growth under high N addition. The saturation response of ER was mainly due to decreases in aboveground plant respiration and soil microbial respiration under high N addition, while the N-induced reduction in soil pH caused declines in soil microbial respiration. We also found that various components of ER, including aboveground plant respiration, soil respiration, root respiration, and microbial respiration, responded differentially to the N addition gradient. The results reveal temporal dynamics of N impacts and the rapid shift of ecosystem C cycle from N limitation to N saturation. These findings are helpful for better understanding and model projection of future terrestrial C sequestration under rising N deposition.

  16. Sky with Ocean Joined, Presented at Proceedings of the Sesquicentennial Symposia Held at Washington, DC on 5-8 December 1980

    DTIC Science & Technology

    1983-12-01

    nal % with publications principally by Lewis Boss, the editor, and individual pieces by G. W. Hill and Seth C. Chandler .22 First, Boss raised the...Communication," Astronomical Journal, 19 (April 14, 1898), 4-5. Sec also. Scth C. Chandler . "The Aberra- tion-Constant of the French Con fere nee...34 Astronomical Journal, 18 (February 10, 1898), 149-152: in this article. Chandler used essentially (he same arguments that Ncwcomb employed at the

  17. A Concept for Quantifying the Readiness Contribution of Proposed Army Facilities.

    DTIC Science & Technology

    1982-04-01

    PROGRAM IPROGRA SIZE OF EEC. EC. FACTORS AT RESPECTIVE MERGE LEVELS IFACILITY FACILITY FACILITYI USING DELPHI INEEDS-- NEES-- NEEDS-- PROCESS IDCSLOGI...OBJECTIVES (MISSIONS) USING DELPHI PROCESS ll~ll~ SIS’ANOARD OBJECTIVES HIERARCHY r, ,------------ EXPERTS SCOpt I I FUNCTIONAL I DETERMINE I SIGNIFICANCEI...RELATIVE L--------J L....-J WORTH OF r r-- - ENTITIES I INTENSITY I IOPERATIONALI USING DELPHI 9 OF NEED ISIGNIFICANCE PROCESS Ir - 1 REL.ATION T TE

  18. Physics and Applications of Defects in Advanced Semiconductors. Materials Research Society Symposium Proceedings. Volume 325

    DTIC Science & Technology

    1994-01-01

    325). Includes bibliographical references and index. ISBN: 1-55899-224-3 1. Semiconductors-Defects--Congresses. 2. Quantum wells -Congresses. 3...John D. Dow, Jun Sben, Shang Yusn Ren, and William E. Packard *OPTICAL SPECTROSCOPY OF DEFECTS IN GauAIGaAs MULTIPLE QUANTUM WELLS ...EFFECTS OF DEFECTS IN GaAs/AIGaAs QUANTUM WELLS ................... 43 O.L. Rusto, V. Rehn, T.W. Nee, and K.A. Dumas *EFFECTS OF IMPURITIES ON THE

  19. Flux frequency analysis of seasonally dry ecosystem fluxes in two unique biomes of Sonora Mexico

    NASA Astrophysics Data System (ADS)

    Verduzco, V. S.; Yepez, E. A.; Robles-Morua, A.; Garatuza, J.; Rodriguez, J. C.; Watts, C.

    2013-05-01

    Complex dynamics from the interactions of ecosystems processes makes difficult to model the behavior of ecosystems fluxes of carbon and water in response to the variation of environmental and biological drivers. Although process oriented ecosystem models are critical tools for studying land-atmosphere fluxes, its validity depends on the appropriate parameterization of equations describing temporal and spatial changes of model state variables and their interactions. This constraint often leads to discrepancies between model simulations and observed data that reduce models reliability especially in arid and semiarid ecosystems. In the semiarid north western Mexico, ecosystem processes are fundamentally controlled by the seasonality of water and the intermittence of rain pulses which are conditions that require calibration of specific fitting functions to describe the response of ecosystem variables (i.e. NEE, GPP, ET, respiration) to these wetting and drying periods. The goal is to find functions that describe the magnitude of ecosystem fluxes during individual rain pulses and the seasonality of the ecosystem. Relaying on five years of eddy covariance flux data of a tropical dry forest and a subtropical shrubland we present a flux frequency analysis that describe the variation of net ecosystem exchange (NEE) of CO2 to highlight the relevance of pulse driven dynamics controlling this flux. Preliminary results of flux frequency analysis of NEE indicate that these ecosystems are strongly controlled by the frequency distribution of rain. Also, the output of fitting functions for NEE, GPP, ET and respiration using semi-empirical functions applied at specific rain pulses compared with season-long statistically generated simulations do not agree. Seasonality and the intrinsic nature of individual pulses have different effects on ecosystem flux responses. This suggests that relationships between the nature of seasonality and individual pulses can help improve the

  20. An Investigation of Constitutive Models for Predicting Viscoplastic Response during Cyclic Loading.

    DTIC Science & Technology

    1988-06-01

    1485 NEE TGTINOh CNTIIE OELSRPE DEIETN I lflfllfllfllflfflfflf I EfLlllfffflllfff ’., 11111l . - 2-8 L 0 * 12V 1-25~ Woo 0 -U I IDTIC ~ JUN 23 98 OF AN...progressive error when performing cre.ep predictions using corn ipiter sNvsteins whose accu - - racy is less than that of ti, \\ \\X II 7,0 N 24 00 000 I